/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h

Bug Summary

File:	include/llvm/Support/Error.h
Warning:	line 200, column 5 Potential leak of memory pointed to by 'Payload._M_t._M_head_impl'

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ELF.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-9/lib/clang/9.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/lib/Object -I /build/llvm-toolchain-snapshot-9~svn362543/lib/Object -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/include -I /build/llvm-toolchain-snapshot-9~svn362543/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/9.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-9/lib/clang/9.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/lib/Object -fdebug-prefix-map=/build/llvm-toolchain-snapshot-9~svn362543=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2019-06-05-060531-1271-1 -x c++ /build/llvm-toolchain-snapshot-9~svn362543/lib/Object/ELF.cpp -faddrsig

/build/llvm-toolchain-snapshot-9~svn362543/lib/Object/ELF.cpp

→

1//===- ELF.cpp - ELF object file implementation ---------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//

9#include "llvm/Object/ELF.h"
10#include "llvm/BinaryFormat/ELF.h"
11#include "llvm/Support/LEB128.h"

13using namespace llvm;
14using namespace object;

16#define STRINGIFY_ENUM_CASE(ns, name)case ns::name: return "name";                                          \
case ns::name:                                                               \
  return #name;

20#define ELF_RELOC(name, value) STRINGIFY_ENUM_CASE(ELF, name)case ELF::name: return "name";

22StringRef llvm::object::getELFRelocationTypeName(uint32_t Machine,
                                               uint32_t Type) {
switch (Machine) {
case ELF::EM_X86_64:
  switch (Type) {
27#include "llvm/BinaryFormat/ELFRelocs/x86_64.def"
  default:
    break;
  }
  break;
case ELF::EM_386:
case ELF::EM_IAMCU:
  switch (Type) {
35#include "llvm/BinaryFormat/ELFRelocs/i386.def"
  default:
    break;
  }
  break;
case ELF::EM_MIPS:
  switch (Type) {
42#include "llvm/BinaryFormat/ELFRelocs/Mips.def"
  default:
    break;
  }
  break;
case ELF::EM_AARCH64:
  switch (Type) {
49#include "llvm/BinaryFormat/ELFRelocs/AArch64.def"
  default:
    break;
  }
  break;
case ELF::EM_ARM:
  switch (Type) {
56#include "llvm/BinaryFormat/ELFRelocs/ARM.def"
  default:
    break;
  }
  break;
case ELF::EM_ARC_COMPACT:
case ELF::EM_ARC_COMPACT2:
  switch (Type) {
64#include "llvm/BinaryFormat/ELFRelocs/ARC.def"
  default:
    break;
  }
  break;
case ELF::EM_AVR:
  switch (Type) {
71#include "llvm/BinaryFormat/ELFRelocs/AVR.def"
  default:
    break;
  }
  break;
case ELF::EM_HEXAGON:
  switch (Type) {
78#include "llvm/BinaryFormat/ELFRelocs/Hexagon.def"
  default:
    break;
  }
  break;
case ELF::EM_LANAI:
  switch (Type) {
85#include "llvm/BinaryFormat/ELFRelocs/Lanai.def"
  default:
    break;
  }
  break;
case ELF::EM_PPC:
  switch (Type) {
92#include "llvm/BinaryFormat/ELFRelocs/PowerPC.def"
  default:
    break;
  }
  break;
case ELF::EM_PPC64:
  switch (Type) {
99#include "llvm/BinaryFormat/ELFRelocs/PowerPC64.def"
  default:
    break;
  }
  break;
case ELF::EM_RISCV:
  switch (Type) {
106#include "llvm/BinaryFormat/ELFRelocs/RISCV.def"
  default:
    break;
  }
  break;
case ELF::EM_S390:
  switch (Type) {
113#include "llvm/BinaryFormat/ELFRelocs/SystemZ.def"
  default:
    break;
  }
  break;
case ELF::EM_SPARC:
case ELF::EM_SPARC32PLUS:
case ELF::EM_SPARCV9:
  switch (Type) {
122#include "llvm/BinaryFormat/ELFRelocs/Sparc.def"
  default:
    break;
  }
  break;
case ELF::EM_AMDGPU:
  switch (Type) {
129#include "llvm/BinaryFormat/ELFRelocs/AMDGPU.def"
  default:
    break;
  }
  break;
case ELF::EM_BPF:
  switch (Type) {
136#include "llvm/BinaryFormat/ELFRelocs/BPF.def"
  default:
    break;
  }
  break;
case ELF::EM_MSP430:
  switch (Type) {
143#include "llvm/BinaryFormat/ELFRelocs/MSP430.def"
  default:
    break;
  }
  break;
default:
  break;
}
return "Unknown";
152}

154#undef ELF_RELOC

156uint32_t llvm::object::getELFRelativeRelocationType(uint32_t Machine) {
switch (Machine) {
case ELF::EM_X86_64:
  return ELF::R_X86_64_RELATIVE;
case ELF::EM_386:
case ELF::EM_IAMCU:
  return ELF::R_386_RELATIVE;
case ELF::EM_MIPS:
  break;
case ELF::EM_AARCH64:
  return ELF::R_AARCH64_RELATIVE;
case ELF::EM_ARM:
  return ELF::R_ARM_RELATIVE;
case ELF::EM_ARC_COMPACT:
case ELF::EM_ARC_COMPACT2:
  return ELF::R_ARC_RELATIVE;
case ELF::EM_AVR:
  break;
case ELF::EM_HEXAGON:
  return ELF::R_HEX_RELATIVE;
case ELF::EM_LANAI:
  break;
case ELF::EM_PPC:
  break;
case ELF::EM_PPC64:
  return ELF::R_PPC64_RELATIVE;
case ELF::EM_RISCV:
  return ELF::R_RISCV_RELATIVE;
case ELF::EM_S390:
  return ELF::R_390_RELATIVE;
case ELF::EM_SPARC:
case ELF::EM_SPARC32PLUS:
case ELF::EM_SPARCV9:
  return ELF::R_SPARC_RELATIVE;
case ELF::EM_AMDGPU:
  break;
case ELF::EM_BPF:
  break;
default:
  break;
}
return 0;
198}

200StringRef llvm::object::getELFSectionTypeName(uint32_t Machine, unsigned Type) {
switch (Machine) {
case ELF::EM_ARM:
  switch (Type) {
    STRINGIFY_ENUM_CASE(ELF, SHT_ARM_EXIDX)case ELF::SHT_ARM_EXIDX: return "SHT_ARM_EXIDX";;
    STRINGIFY_ENUM_CASE(ELF, SHT_ARM_PREEMPTMAP)case ELF::SHT_ARM_PREEMPTMAP: return "SHT_ARM_PREEMPTMAP";;
    STRINGIFY_ENUM_CASE(ELF, SHT_ARM_ATTRIBUTES)case ELF::SHT_ARM_ATTRIBUTES: return "SHT_ARM_ATTRIBUTES";;
    STRINGIFY_ENUM_CASE(ELF, SHT_ARM_DEBUGOVERLAY)case ELF::SHT_ARM_DEBUGOVERLAY: return "SHT_ARM_DEBUGOVERLAY"
;;
    STRINGIFY_ENUM_CASE(ELF, SHT_ARM_OVERLAYSECTION)case ELF::SHT_ARM_OVERLAYSECTION: return "SHT_ARM_OVERLAYSECTION"
;;
  }
  break;
case ELF::EM_HEXAGON:
  switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_HEX_ORDERED)case ELF::SHT_HEX_ORDERED: return "SHT_HEX_ORDERED";; }
  break;
case ELF::EM_X86_64:
  switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_X86_64_UNWIND)case ELF::SHT_X86_64_UNWIND: return "SHT_X86_64_UNWIND";; }
  break;
case ELF::EM_MIPS:
case ELF::EM_MIPS_RS3_LE:
  switch (Type) {
    STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_REGINFO)case ELF::SHT_MIPS_REGINFO: return "SHT_MIPS_REGINFO";;
    STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_OPTIONS)case ELF::SHT_MIPS_OPTIONS: return "SHT_MIPS_OPTIONS";;
    STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_DWARF)case ELF::SHT_MIPS_DWARF: return "SHT_MIPS_DWARF";;
    STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_ABIFLAGS)case ELF::SHT_MIPS_ABIFLAGS: return "SHT_MIPS_ABIFLAGS";;
  }
  break;
default:
  break;
}

switch (Type) {
  STRINGIFY_ENUM_CASE(ELF, SHT_NULL)case ELF::SHT_NULL: return "SHT_NULL";;
  STRINGIFY_ENUM_CASE(ELF, SHT_PROGBITS)case ELF::SHT_PROGBITS: return "SHT_PROGBITS";;
  STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB)case ELF::SHT_SYMTAB: return "SHT_SYMTAB";;
  STRINGIFY_ENUM_CASE(ELF, SHT_STRTAB)case ELF::SHT_STRTAB: return "SHT_STRTAB";;
  STRINGIFY_ENUM_CASE(ELF, SHT_RELA)case ELF::SHT_RELA: return "SHT_RELA";;
  STRINGIFY_ENUM_CASE(ELF, SHT_HASH)case ELF::SHT_HASH: return "SHT_HASH";;
  STRINGIFY_ENUM_CASE(ELF, SHT_DYNAMIC)case ELF::SHT_DYNAMIC: return "SHT_DYNAMIC";;
  STRINGIFY_ENUM_CASE(ELF, SHT_NOTE)case ELF::SHT_NOTE: return "SHT_NOTE";;
  STRINGIFY_ENUM_CASE(ELF, SHT_NOBITS)case ELF::SHT_NOBITS: return "SHT_NOBITS";;
  STRINGIFY_ENUM_CASE(ELF, SHT_REL)case ELF::SHT_REL: return "SHT_REL";;
  STRINGIFY_ENUM_CASE(ELF, SHT_SHLIB)case ELF::SHT_SHLIB: return "SHT_SHLIB";;
  STRINGIFY_ENUM_CASE(ELF, SHT_DYNSYM)case ELF::SHT_DYNSYM: return "SHT_DYNSYM";;
  STRINGIFY_ENUM_CASE(ELF, SHT_INIT_ARRAY)case ELF::SHT_INIT_ARRAY: return "SHT_INIT_ARRAY";;
  STRINGIFY_ENUM_CASE(ELF, SHT_FINI_ARRAY)case ELF::SHT_FINI_ARRAY: return "SHT_FINI_ARRAY";;
  STRINGIFY_ENUM_CASE(ELF, SHT_PREINIT_ARRAY)case ELF::SHT_PREINIT_ARRAY: return "SHT_PREINIT_ARRAY";;
  STRINGIFY_ENUM_CASE(ELF, SHT_GROUP)case ELF::SHT_GROUP: return "SHT_GROUP";;
  STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB_SHNDX)case ELF::SHT_SYMTAB_SHNDX: return "SHT_SYMTAB_SHNDX";;
  STRINGIFY_ENUM_CASE(ELF, SHT_RELR)case ELF::SHT_RELR: return "SHT_RELR";;
  STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_REL)case ELF::SHT_ANDROID_REL: return "SHT_ANDROID_REL";;
  STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELA)case ELF::SHT_ANDROID_RELA: return "SHT_ANDROID_RELA";;
  STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELR)case ELF::SHT_ANDROID_RELR: return "SHT_ANDROID_RELR";;
  STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ODRTAB)case ELF::SHT_LLVM_ODRTAB: return "SHT_LLVM_ODRTAB";;
  STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_LINKER_OPTIONS)case ELF::SHT_LLVM_LINKER_OPTIONS: return "SHT_LLVM_LINKER_OPTIONS"
;;
  STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CALL_GRAPH_PROFILE)case ELF::SHT_LLVM_CALL_GRAPH_PROFILE: return "SHT_LLVM_CALL_GRAPH_PROFILE"
;;
  STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ADDRSIG)case ELF::SHT_LLVM_ADDRSIG: return "SHT_LLVM_ADDRSIG";;
  STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_DEPENDENT_LIBRARIES)case ELF::SHT_LLVM_DEPENDENT_LIBRARIES: return "SHT_LLVM_DEPENDENT_LIBRARIES"
;;
  STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_SYMPART)case ELF::SHT_LLVM_SYMPART: return "SHT_LLVM_SYMPART";;
  STRINGIFY_ENUM_CASE(ELF, SHT_GNU_ATTRIBUTES)case ELF::SHT_GNU_ATTRIBUTES: return "SHT_GNU_ATTRIBUTES";;
  STRINGIFY_ENUM_CASE(ELF, SHT_GNU_HASH)case ELF::SHT_GNU_HASH: return "SHT_GNU_HASH";;
  STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verdef)case ELF::SHT_GNU_verdef: return "SHT_GNU_verdef";;
  STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verneed)case ELF::SHT_GNU_verneed: return "SHT_GNU_verneed";;
  STRINGIFY_ENUM_CASE(ELF, SHT_GNU_versym)case ELF::SHT_GNU_versym: return "SHT_GNU_versym";;
default:
  return "Unknown";
}
266}

268template <class ELFT>
269Expected<std::vector<typename ELFT::Rela>>
270ELFFile<ELFT>::decode_relrs(Elf_Relr_Range relrs) const {
// This function decodes the contents of an SHT_RELR packed relocation
// section.
//
// Proposal for adding SHT_RELR sections to generic-abi is here:
//   https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
//
// The encoded sequence of Elf64_Relr entries in a SHT_RELR section looks
// like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
//
// i.e. start with an address, followed by any number of bitmaps. The address
// entry encodes 1 relocation. The subsequent bitmap entries encode up to 63
// relocations each, at subsequent offsets following the last address entry.
//
// The bitmap entries must have 1 in the least significant bit. The assumption
// here is that an address cannot have 1 in lsb. Odd addresses are not
// supported.
//
// Excluding the least significant bit in the bitmap, each non-zero bit in
// the bitmap represents a relocation to be applied to a corresponding machine
// word that follows the base address word. The second least significant bit
// represents the machine word immediately following the initial address, and
// each bit that follows represents the next word, in linear order. As such,
// a single bitmap can encode up to 31 relocations in a 32-bit object, and
// 63 relocations in a 64-bit object.
//
// This encoding has a couple of interesting properties:
// 1. Looking at any entry, it is clear whether it's an address or a bitmap:
//    even means address, odd means bitmap.
// 2. Just a simple list of addresses is a valid encoding.

Elf_Rela Rela;
Rela.r_info = 0;
Rela.r_addend = 0;
Rela.setType(getRelativeRelocationType(), false);
std::vector<Elf_Rela> Relocs;

// Word type: uint32_t for Elf32, and uint64_t for Elf64.
typedef typename ELFT::uint Word;

// Word size in number of bytes.
const size_t WordSize = sizeof(Word);

// Number of bits used for the relocation offsets bitmap.
// These many relative relocations can be encoded in a single entry.
const size_t NBits = 8*WordSize - 1;

Word Base = 0;
for (const Elf_Relr &R : relrs) {
  Word Entry = R;
  if ((Entry&1) == 0) {
    // Even entry: encodes the offset for next relocation.
    Rela.r_offset = Entry;
    Relocs.push_back(Rela);
    // Set base offset for subsequent bitmap entries.
    Base = Entry + WordSize;
    continue;
  }

  // Odd entry: encodes bitmap for relocations starting at base.
  Word Offset = Base;
  while (Entry != 0) {
    Entry >>= 1;
    if ((Entry&1) != 0) {
      Rela.r_offset = Offset;
      Relocs.push_back(Rela);
    }
    Offset += WordSize;
  }

  // Advance base offset by NBits words.
  Base += NBits * WordSize;
}

return Relocs;
345}

347template <class ELFT>
348Expected<std::vector<typename ELFT::Rela>>
349ELFFile<ELFT>::android_relas(const Elf_Shdr *Sec) const {
// This function reads relocations in Android's packed relocation format,
// which is based on SLEB128 and delta encoding.
Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec);
1
Calling 'ELFFile::getSectionContents'→
if (!ContentsOrErr)
  return ContentsOrErr.takeError();
const uint8_t *Cur = ContentsOrErr->begin();
const uint8_t *End = ContentsOrErr->end();
if (ContentsOrErr->size() < 4 || Cur[0] != 'A' || Cur[1] != 'P' ||
    Cur[2] != 'S' || Cur[3] != '2')
  return createError("invalid packed relocation header");
Cur += 4;

const char *ErrStr = nullptr;
auto ReadSLEB = [&]() -> int64_t {
  if (ErrStr)
    return 0;
  unsigned Len;
  int64_t Result = decodeSLEB128(Cur, &Len, End, &ErrStr);
  Cur += Len;
  return Result;
};

uint64_t NumRelocs = ReadSLEB();
uint64_t Offset = ReadSLEB();
uint64_t Addend = 0;

if (ErrStr)
  return createError(ErrStr);

std::vector<Elf_Rela> Relocs;
Relocs.reserve(NumRelocs);
while (NumRelocs) {
  uint64_t NumRelocsInGroup = ReadSLEB();
  if (NumRelocsInGroup > NumRelocs)
    return createError("relocation group unexpectedly large");
  NumRelocs -= NumRelocsInGroup;

  uint64_t GroupFlags = ReadSLEB();
  bool GroupedByInfo = GroupFlags & ELF::RELOCATION_GROUPED_BY_INFO_FLAG;
  bool GroupedByOffsetDelta = GroupFlags & ELF::RELOCATION_GROUPED_BY_OFFSET_DELTA_FLAG;
  bool GroupedByAddend = GroupFlags & ELF::RELOCATION_GROUPED_BY_ADDEND_FLAG;
  bool GroupHasAddend = GroupFlags & ELF::RELOCATION_GROUP_HAS_ADDEND_FLAG;

  uint64_t GroupOffsetDelta;
  if (GroupedByOffsetDelta)
    GroupOffsetDelta = ReadSLEB();

  uint64_t GroupRInfo;
  if (GroupedByInfo)
    GroupRInfo = ReadSLEB();

  if (GroupedByAddend && GroupHasAddend)
    Addend += ReadSLEB();

  if (!GroupHasAddend)
    Addend = 0;

  for (uint64_t I = 0; I != NumRelocsInGroup; ++I) {
    Elf_Rela R;
    Offset += GroupedByOffsetDelta ? GroupOffsetDelta : ReadSLEB();
    R.r_offset = Offset;
    R.r_info = GroupedByInfo ? GroupRInfo : ReadSLEB();
    if (GroupHasAddend && !GroupedByAddend)
      Addend += ReadSLEB();
    R.r_addend = Addend;
    Relocs.push_back(R);

    if (ErrStr)
      return createError(ErrStr);
  }

  if (ErrStr)
    return createError(ErrStr);
}

return Relocs;
426}

428template <class ELFT>
429std::string ELFFile<ELFT>::getDynamicTagAsString(unsigned Arch,
                                               uint64_t Type) const {
431#define DYNAMIC_STRINGIFY_ENUM(tag, value)                                     \
case value:                                                                  \
  return #tag;

435#define DYNAMIC_TAG(n, v)
switch (Arch) {
case ELF::EM_AARCH64:
  switch (Type) {
439#define AARCH64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
440#include "llvm/BinaryFormat/DynamicTags.def"
441#undef AARCH64_DYNAMIC_TAG
  }
  break;

case ELF::EM_HEXAGON:
  switch (Type) {
447#define HEXAGON_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
448#include "llvm/BinaryFormat/DynamicTags.def"
449#undef HEXAGON_DYNAMIC_TAG
  }
  break;

case ELF::EM_MIPS:
  switch (Type) {
455#define MIPS_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
456#include "llvm/BinaryFormat/DynamicTags.def"
457#undef MIPS_DYNAMIC_TAG
  }
  break;

case ELF::EM_PPC64:
  switch (Type) {
463#define PPC64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
464#include "llvm/BinaryFormat/DynamicTags.def"
465#undef PPC64_DYNAMIC_TAG
  }
  break;
}
469#undef DYNAMIC_TAG
switch (Type) {
471// Now handle all dynamic tags except the architecture specific ones
472#define AARCH64_DYNAMIC_TAG(name, value)
473#define MIPS_DYNAMIC_TAG(name, value)
474#define HEXAGON_DYNAMIC_TAG(name, value)
475#define PPC64_DYNAMIC_TAG(name, value)
476// Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
477#define DYNAMIC_TAG_MARKER(name, value)
478#define DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
479#include "llvm/BinaryFormat/DynamicTags.def"
480#undef DYNAMIC_TAG
481#undef AARCH64_DYNAMIC_TAG
482#undef MIPS_DYNAMIC_TAG
483#undef HEXAGON_DYNAMIC_TAG
484#undef PPC64_DYNAMIC_TAG
485#undef DYNAMIC_TAG_MARKER
486#undef DYNAMIC_STRINGIFY_ENUM
default:
  return "<unknown:>0x" + utohexstr(Type, true);
}
490}

492template <class ELFT>
493std::string ELFFile<ELFT>::getDynamicTagAsString(uint64_t Type) const {
return getDynamicTagAsString(getHeader()->e_machine, Type);
495}

497template <class ELFT>
498Expected<typename ELFT::DynRange> ELFFile<ELFT>::dynamicEntries() const {
ArrayRef<Elf_Dyn> Dyn;
size_t DynSecSize = 0;

auto ProgramHeadersOrError = program_headers();
if (!ProgramHeadersOrError)
  return ProgramHeadersOrError.takeError();

for (const Elf_Phdr &Phdr : *ProgramHeadersOrError) {
  if (Phdr.p_type == ELF::PT_DYNAMIC) {
    Dyn = makeArrayRef(
        reinterpret_cast<const Elf_Dyn *>(base() + Phdr.p_offset),
        Phdr.p_filesz / sizeof(Elf_Dyn));
    DynSecSize = Phdr.p_filesz;
    break;
  }
}

// If we can't find the dynamic section in the program headers, we just fall
// back on the sections.
if (Dyn.empty()) {
  auto SectionsOrError = sections();
  if (!SectionsOrError)
    return SectionsOrError.takeError();

  for (const Elf_Shdr &Sec : *SectionsOrError) {
    if (Sec.sh_type == ELF::SHT_DYNAMIC) {
      Expected<ArrayRef<Elf_Dyn>> DynOrError =
          getSectionContentsAsArray<Elf_Dyn>(&Sec);
      if (!DynOrError)
        return DynOrError.takeError();
      Dyn = *DynOrError;
      DynSecSize = Sec.sh_size;
      break;
    }
  }

  if (!Dyn.data())
    return ArrayRef<Elf_Dyn>();
}

if (Dyn.empty())
  return createError("invalid empty dynamic section");

if (DynSecSize % sizeof(Elf_Dyn) != 0)
  return createError("malformed dynamic section");

if (Dyn.back().d_tag != ELF::DT_NULL)
  return createError("dynamic sections must be DT_NULL terminated");

return Dyn;
549}

551template <class ELFT>
552Expected<const uint8_t *> ELFFile<ELFT>::toMappedAddr(uint64_t VAddr) const {
auto ProgramHeadersOrError = program_headers();
if (!ProgramHeadersOrError)
  return ProgramHeadersOrError.takeError();

llvm::SmallVector<Elf_Phdr *, 4> LoadSegments;

for (const Elf_Phdr &Phdr : *ProgramHeadersOrError)
  if (Phdr.p_type == ELF::PT_LOAD)
    LoadSegments.push_back(const_cast<Elf_Phdr *>(&Phdr));

const Elf_Phdr *const *I =
    std::upper_bound(LoadSegments.begin(), LoadSegments.end(), VAddr,
                     [](uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
                       return VAddr < Phdr->p_vaddr;
                     });

if (I == LoadSegments.begin())
  return createError("Virtual address is not in any segment");
--I;
const Elf_Phdr &Phdr = **I;
uint64_t Delta = VAddr - Phdr.p_vaddr;
if (Delta >= Phdr.p_filesz)
  return createError("Virtual address is not in any segment");
return base() + Phdr.p_offset + Delta;
577}

579template class llvm::object::ELFFile<ELF32LE>;
580template class llvm::object::ELFFile<ELF32BE>;
581template class llvm::object::ELFFile<ELF64LE>;
582template class llvm::object::ELFFile<ELF64BE>;

←

/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Object/ELF.h

→

1//===- ELF.h - ELF object file implementation -------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file declares the ELFFile template class.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_OBJECT_ELF_H
14#define LLVM_OBJECT_ELF_H

16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/SmallVector.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/BinaryFormat/ELF.h"
20#include "llvm/Object/ELFTypes.h"
21#include "llvm/Object/Error.h"
22#include "llvm/Support/Endian.h"
23#include "llvm/Support/Error.h"
24#include <cassert>
25#include <cstddef>
26#include <cstdint>
27#include <limits>
28#include <utility>

30namespace llvm {
31namespace object {

33StringRef getELFRelocationTypeName(uint32_t Machine, uint32_t Type);
34uint32_t getELFRelativeRelocationType(uint32_t Machine);
35StringRef getELFSectionTypeName(uint32_t Machine, uint32_t Type);

37// Subclasses of ELFFile may need this for template instantiation
38inline std::pair<unsigned char, unsigned char>
39getElfArchType(StringRef Object) {
if (Object.size() < ELF::EI_NIDENT)
  return std::make_pair((uint8_t)ELF::ELFCLASSNONE,
                        (uint8_t)ELF::ELFDATANONE);
return std::make_pair((uint8_t)Object[ELF::EI_CLASS],
                      (uint8_t)Object[ELF::EI_DATA]);
45}

47static inline Error createError(StringRef Err) {
return make_error<StringError>(Err, object_error::parse_failed);
7
←
Calling 'make_error<llvm::StringError, llvm::StringRef &, llvm::object::object_error>'→
49}

51template <class ELFT>
52class ELFFile {
53public:
LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)using Elf_Addr = typename ELFT::Addr; using Elf_Off = typename
 ELFT::Off; using Elf_Half = typename ELFT::Half; using Elf_Word
 = typename ELFT::Word; using Elf_Sword = typename ELFT::Sword
; using Elf_Xword = typename ELFT::Xword; using Elf_Sxword = typename
 ELFT::Sxword;
using uintX_t = typename ELFT::uint;
using Elf_Ehdr = typename ELFT::Ehdr;
using Elf_Shdr = typename ELFT::Shdr;
using Elf_Sym = typename ELFT::Sym;
using Elf_Dyn = typename ELFT::Dyn;
using Elf_Phdr = typename ELFT::Phdr;
using Elf_Rel = typename ELFT::Rel;
using Elf_Rela = typename ELFT::Rela;
using Elf_Relr = typename ELFT::Relr;
using Elf_Verdef = typename ELFT::Verdef;
using Elf_Verdaux = typename ELFT::Verdaux;
using Elf_Verneed = typename ELFT::Verneed;
using Elf_Vernaux = typename ELFT::Vernaux;
using Elf_Versym = typename ELFT::Versym;
using Elf_Hash = typename ELFT::Hash;
using Elf_GnuHash = typename ELFT::GnuHash;
using Elf_Nhdr = typename ELFT::Nhdr;
using Elf_Note = typename ELFT::Note;
using Elf_Note_Iterator = typename ELFT::NoteIterator;
using Elf_Dyn_Range = typename ELFT::DynRange;
using Elf_Shdr_Range = typename ELFT::ShdrRange;
using Elf_Sym_Range = typename ELFT::SymRange;
using Elf_Rel_Range = typename ELFT::RelRange;
using Elf_Rela_Range = typename ELFT::RelaRange;
using Elf_Relr_Range = typename ELFT::RelrRange;
using Elf_Phdr_Range = typename ELFT::PhdrRange;

const uint8_t *base() const { return Buf.bytes_begin(); }

size_t getBufSize() const { return Buf.size(); }

86private:
StringRef Buf;

ELFFile(StringRef Object);

91public:
const Elf_Ehdr *getHeader() const {
  return reinterpret_cast<const Elf_Ehdr *>(base());
}

template <typename T>
Expected<const T *> getEntry(uint32_t Section, uint32_t Entry) const;
template <typename T>
Expected<const T *> getEntry(const Elf_Shdr *Section, uint32_t Entry) const;

Expected<StringRef> getStringTable(const Elf_Shdr *Section) const;
Expected<StringRef> getStringTableForSymtab(const Elf_Shdr &Section) const;
Expected<StringRef> getStringTableForSymtab(const Elf_Shdr &Section,
                                            Elf_Shdr_Range Sections) const;

Expected<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section) const;
Expected<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section,
                                           Elf_Shdr_Range Sections) const;

StringRef getRelocationTypeName(uint32_t Type) const;
void getRelocationTypeName(uint32_t Type,
                           SmallVectorImpl<char> &Result) const;
uint32_t getRelativeRelocationType() const;

std::string getDynamicTagAsString(unsigned Arch, uint64_t Type) const;
std::string getDynamicTagAsString(uint64_t Type) const;

/// Get the symbol for a given relocation.
Expected<const Elf_Sym *> getRelocationSymbol(const Elf_Rel *Rel,
                                              const Elf_Shdr *SymTab) const;

static Expected<ELFFile> create(StringRef Object);

bool isMipsELF64() const {
  return getHeader()->e_machine == ELF::EM_MIPS &&
         getHeader()->getFileClass() == ELF::ELFCLASS64;
}

bool isMips64EL() const {
  return isMipsELF64() &&
         getHeader()->getDataEncoding() == ELF::ELFDATA2LSB;
}

Expected<Elf_Shdr_Range> sections() const;

Expected<Elf_Dyn_Range> dynamicEntries() const;

Expected<const uint8_t *> toMappedAddr(uint64_t VAddr) const;

Expected<Elf_Sym_Range> symbols(const Elf_Shdr *Sec) const {
  if (!Sec)
    return makeArrayRef<Elf_Sym>(nullptr, nullptr);
  return getSectionContentsAsArray<Elf_Sym>(Sec);
}

Expected<Elf_Rela_Range> relas(const Elf_Shdr *Sec) const {
  return getSectionContentsAsArray<Elf_Rela>(Sec);
}

Expected<Elf_Rel_Range> rels(const Elf_Shdr *Sec) const {
  return getSectionContentsAsArray<Elf_Rel>(Sec);
}

Expected<Elf_Relr_Range> relrs(const Elf_Shdr *Sec) const {
  return getSectionContentsAsArray<Elf_Relr>(Sec);
}

Expected<std::vector<Elf_Rela>> decode_relrs(Elf_Relr_Range relrs) const;

Expected<std::vector<Elf_Rela>> android_relas(const Elf_Shdr *Sec) const;

/// Iterate over program header table.
Expected<Elf_Phdr_Range> program_headers() const {
  if (getHeader()->e_phnum && getHeader()->e_phentsize != sizeof(Elf_Phdr))
    return createError("invalid e_phentsize");
  if (getHeader()->e_phoff +
          (getHeader()->e_phnum * getHeader()->e_phentsize) >
      getBufSize())
    return createError("program headers longer than binary");
  auto *Begin =
      reinterpret_cast<const Elf_Phdr *>(base() + getHeader()->e_phoff);
  return makeArrayRef(Begin, Begin + getHeader()->e_phnum);
}

/// Get an iterator over notes in a program header.
///
/// The program header must be of type \c PT_NOTE.
///
/// \param Phdr the program header to iterate over.
/// \param Err [out] an error to support fallible iteration, which should
///  be checked after iteration ends.
Elf_Note_Iterator notes_begin(const Elf_Phdr &Phdr, Error &Err) const {
  if (Phdr.p_type != ELF::PT_NOTE) {
    Err = createError("attempt to iterate notes of non-note program header");
    return Elf_Note_Iterator(Err);
  }
  if (Phdr.p_offset + Phdr.p_filesz > getBufSize()) {
    Err = createError("invalid program header offset/size");
    return Elf_Note_Iterator(Err);
  }
  return Elf_Note_Iterator(base() + Phdr.p_offset, Phdr.p_filesz, Err);
}

/// Get an iterator over notes in a section.
///
/// The section must be of type \c SHT_NOTE.
///
/// \param Shdr the section to iterate over.
/// \param Err [out] an error to support fallible iteration, which should
///  be checked after iteration ends.
Elf_Note_Iterator notes_begin(const Elf_Shdr &Shdr, Error &Err) const {
  if (Shdr.sh_type != ELF::SHT_NOTE) {
    Err = createError("attempt to iterate notes of non-note section");
    return Elf_Note_Iterator(Err);
  }
  if (Shdr.sh_offset + Shdr.sh_size > getBufSize()) {
    Err = createError("invalid section offset/size");
    return Elf_Note_Iterator(Err);
  }
  return Elf_Note_Iterator(base() + Shdr.sh_offset, Shdr.sh_size, Err);
}

/// Get the end iterator for notes.
Elf_Note_Iterator notes_end() const {
  return Elf_Note_Iterator();
}

/// Get an iterator range over notes of a program header.
///
/// The program header must be of type \c PT_NOTE.
///
/// \param Phdr the program header to iterate over.
/// \param Err [out] an error to support fallible iteration, which should
///  be checked after iteration ends.
iterator_range<Elf_Note_Iterator> notes(const Elf_Phdr &Phdr,
                                        Error &Err) const {
  return make_range(notes_begin(Phdr, Err), notes_end());
}

/// Get an iterator range over notes of a section.
///
/// The section must be of type \c SHT_NOTE.
///
/// \param Shdr the section to iterate over.
/// \param Err [out] an error to support fallible iteration, which should
///  be checked after iteration ends.
iterator_range<Elf_Note_Iterator> notes(const Elf_Shdr &Shdr,
                                        Error &Err) const {
  return make_range(notes_begin(Shdr, Err), notes_end());
}

Expected<StringRef> getSectionStringTable(Elf_Shdr_Range Sections) const;
Expected<uint32_t> getSectionIndex(const Elf_Sym *Sym, Elf_Sym_Range Syms,
                                   ArrayRef<Elf_Word> ShndxTable) const;
Expected<const Elf_Shdr *> getSection(const Elf_Sym *Sym,
                                      const Elf_Shdr *SymTab,
                                      ArrayRef<Elf_Word> ShndxTable) const;
Expected<const Elf_Shdr *> getSection(const Elf_Sym *Sym,
                                      Elf_Sym_Range Symtab,
                                      ArrayRef<Elf_Word> ShndxTable) const;
Expected<const Elf_Shdr *> getSection(uint32_t Index) const;
Expected<const Elf_Shdr *> getSection(const StringRef SectionName) const;

Expected<const Elf_Sym *> getSymbol(const Elf_Shdr *Sec,
                                    uint32_t Index) const;

Expected<StringRef> getSectionName(const Elf_Shdr *Section) const;
Expected<StringRef> getSectionName(const Elf_Shdr *Section,
                                   StringRef DotShstrtab) const;
template <typename T>
Expected<ArrayRef<T>> getSectionContentsAsArray(const Elf_Shdr *Sec) const;
Expected<ArrayRef<uint8_t>> getSectionContents(const Elf_Shdr *Sec) const;
263};

265using ELF32LEFile = ELFFile<ELF32LE>;
266using ELF64LEFile = ELFFile<ELF64LE>;
267using ELF32BEFile = ELFFile<ELF32BE>;
268using ELF64BEFile = ELFFile<ELF64BE>;

270template <class ELFT>
271inline Expected<const typename ELFT::Shdr *>
272getSection(typename ELFT::ShdrRange Sections, uint32_t Index) {
if (Index >= Sections.size())
  return createError("invalid section index");
return &Sections[Index];
276}

278template <class ELFT>
279inline Expected<uint32_t>
280getExtendedSymbolTableIndex(const typename ELFT::Sym *Sym,
                          const typename ELFT::Sym *FirstSym,
                          ArrayRef<typename ELFT::Word> ShndxTable) {
assert(Sym->st_shndx == ELF::SHN_XINDEX)((Sym->st_shndx == ELF::SHN_XINDEX) ? static_cast<void>
 (0) : __assert_fail ("Sym->st_shndx == ELF::SHN_XINDEX", "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Object/ELF.h"
, 283, __PRETTY_FUNCTION__));
unsigned Index = Sym - FirstSym;
if (Index >= ShndxTable.size())
  return createError("index past the end of the symbol table");

// The size of the table was checked in getSHNDXTable.
return ShndxTable[Index];
290}

292template <class ELFT>
293Expected<uint32_t>
294ELFFile<ELFT>::getSectionIndex(const Elf_Sym *Sym, Elf_Sym_Range Syms,
                             ArrayRef<Elf_Word> ShndxTable) const {
uint32_t Index = Sym->st_shndx;
if (Index == ELF::SHN_XINDEX) {
  auto ErrorOrIndex = getExtendedSymbolTableIndex<ELFT>(
      Sym, Syms.begin(), ShndxTable);
  if (!ErrorOrIndex)
    return ErrorOrIndex.takeError();
  return *ErrorOrIndex;
}
if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
  return 0;
return Index;
307}

309template <class ELFT>
310Expected<const typename ELFT::Shdr *>
311ELFFile<ELFT>::getSection(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
                        ArrayRef<Elf_Word> ShndxTable) const {
auto SymsOrErr = symbols(SymTab);
if (!SymsOrErr)
  return SymsOrErr.takeError();
return getSection(Sym, *SymsOrErr, ShndxTable);
317}

319template <class ELFT>
320Expected<const typename ELFT::Shdr *>
321ELFFile<ELFT>::getSection(const Elf_Sym *Sym, Elf_Sym_Range Symbols,
                        ArrayRef<Elf_Word> ShndxTable) const {
auto IndexOrErr = getSectionIndex(Sym, Symbols, ShndxTable);
if (!IndexOrErr)
  return IndexOrErr.takeError();
uint32_t Index = *IndexOrErr;
if (Index == 0)
  return nullptr;
return getSection(Index);
330}

332template <class ELFT>
333inline Expected<const typename ELFT::Sym *>
334getSymbol(typename ELFT::SymRange Symbols, uint32_t Index) {
if (Index >= Symbols.size())
  return createError("invalid symbol index");
return &Symbols[Index];
338}

340template <class ELFT>
341Expected<const typename ELFT::Sym *>
342ELFFile<ELFT>::getSymbol(const Elf_Shdr *Sec, uint32_t Index) const {
auto SymtabOrErr = symbols(Sec);
if (!SymtabOrErr)
  return SymtabOrErr.takeError();
return object::getSymbol<ELFT>(*SymtabOrErr, Index);
347}

349template <class ELFT>
350template <typename T>
351Expected<ArrayRef<T>>
352ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr *Sec) const {
if (Sec->sh_entsize != sizeof(T) && sizeof(T) != 1)
3
←
Assuming the condition is false→
  return createError("invalid sh_entsize");

uintX_t Offset = Sec->sh_offset;
uintX_t Size = Sec->sh_size;

if (Size % sizeof(T))
4
←
Taking false branch→
  return createError("size is not a multiple of sh_entsize");
if ((std::numeric_limits<uintX_t>::max() - Offset < Size) ||
5
←
Assuming the condition is true→
    Offset + Size > Buf.size())
  return createError("invalid section offset");
6
←
Calling 'createError'→

if (Offset % alignof(T))
  return createError("unaligned data");

const T *Start = reinterpret_cast<const T *>(base() + Offset);
return makeArrayRef(Start, Size / sizeof(T));
370}

372template <class ELFT>
373Expected<ArrayRef<uint8_t>>
374ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
return getSectionContentsAsArray<uint8_t>(Sec);
2
←
Calling 'ELFFile::getSectionContentsAsArray'→
376}

378template <class ELFT>
379StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
return getELFRelocationTypeName(getHeader()->e_machine, Type);
381}

383template <class ELFT>
384void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
                                        SmallVectorImpl<char> &Result) const {
if (!isMipsELF64()) {
  StringRef Name = getRelocationTypeName(Type);
  Result.append(Name.begin(), Name.end());
} else {
  // The Mips N64 ABI allows up to three operations to be specified per
  // relocation record. Unfortunately there's no easy way to test for the
  // presence of N64 ELFs as they have no special flag that identifies them
  // as being N64. We can safely assume at the moment that all Mips
  // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
  // information to disambiguate between old vs new ABIs.
  uint8_t Type1 = (Type >> 0) & 0xFF;
  uint8_t Type2 = (Type >> 8) & 0xFF;
  uint8_t Type3 = (Type >> 16) & 0xFF;

  // Concat all three relocation type names.
  StringRef Name = getRelocationTypeName(Type1);
  Result.append(Name.begin(), Name.end());

  Name = getRelocationTypeName(Type2);
  Result.append(1, '/');
  Result.append(Name.begin(), Name.end());

  Name = getRelocationTypeName(Type3);
  Result.append(1, '/');
  Result.append(Name.begin(), Name.end());
}
412}

414template <class ELFT>
415uint32_t ELFFile<ELFT>::getRelativeRelocationType() const {
return getELFRelativeRelocationType(getHeader()->e_machine);
417}

419template <class ELFT>
420Expected<const typename ELFT::Sym *>
421ELFFile<ELFT>::getRelocationSymbol(const Elf_Rel *Rel,
                                 const Elf_Shdr *SymTab) const {
uint32_t Index = Rel->getSymbol(isMips64EL());
if (Index == 0)
  return nullptr;
return getEntry<Elf_Sym>(SymTab, Index);
427}

429template <class ELFT>
430Expected<StringRef>
431ELFFile<ELFT>::getSectionStringTable(Elf_Shdr_Range Sections) const {
uint32_t Index = getHeader()->e_shstrndx;
if (Index == ELF::SHN_XINDEX)
  Index = Sections[0].sh_link;

if (!Index) // no section string table.
  return "";
if (Index >= Sections.size())
  return createError("invalid section index");
return getStringTable(&Sections[Index]);
441}

443template <class ELFT> ELFFile<ELFT>::ELFFile(StringRef Object) : Buf(Object) {}

445template <class ELFT>
446Expected<ELFFile<ELFT>> ELFFile<ELFT>::create(StringRef Object) {
if (sizeof(Elf_Ehdr) > Object.size())
  return createError("Invalid buffer");
return ELFFile(Object);
450}

452template <class ELFT>
453Expected<typename ELFT::ShdrRange> ELFFile<ELFT>::sections() const {
const uintX_t SectionTableOffset = getHeader()->e_shoff;
if (SectionTableOffset == 0)
  return ArrayRef<Elf_Shdr>();

if (getHeader()->e_shentsize != sizeof(Elf_Shdr))
  return createError(
      "invalid section header entry size (e_shentsize) in ELF header");

const uint64_t FileSize = Buf.size();

if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize)
  return createError("section header table goes past the end of the file");

// Invalid address alignment of section headers
if (SectionTableOffset & (alignof(Elf_Shdr) - 1))
  return createError("invalid alignment of section headers");

const Elf_Shdr *First =
    reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);

uintX_t NumSections = getHeader()->e_shnum;
if (NumSections == 0)
  NumSections = First->sh_size;

if (NumSections > UINT64_MAX(18446744073709551615UL) / sizeof(Elf_Shdr))
  return createError("section table goes past the end of file");

const uint64_t SectionTableSize = NumSections * sizeof(Elf_Shdr);

// Section table goes past end of file!
if (SectionTableOffset + SectionTableSize > FileSize)
  return createError("section table goes past the end of file");

return makeArrayRef(First, NumSections);
488}

490template <class ELFT>
491template <typename T>
492Expected<const T *> ELFFile<ELFT>::getEntry(uint32_t Section,
                                          uint32_t Entry) const {
auto SecOrErr = getSection(Section);
if (!SecOrErr)
  return SecOrErr.takeError();
return getEntry<T>(*SecOrErr, Entry);
498}

500template <class ELFT>
501template <typename T>
502Expected<const T *> ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
                                          uint32_t Entry) const {
if (sizeof(T) != Section->sh_entsize)
  return createError("invalid sh_entsize");
size_t Pos = Section->sh_offset + Entry * sizeof(T);
if (Pos + sizeof(T) > Buf.size())
  return createError("invalid section offset");
return reinterpret_cast<const T *>(base() + Pos);
510}

512template <class ELFT>
513Expected<const typename ELFT::Shdr *>
514ELFFile<ELFT>::getSection(uint32_t Index) const {
auto TableOrErr = sections();
if (!TableOrErr)
  return TableOrErr.takeError();
return object::getSection<ELFT>(*TableOrErr, Index);
519}

521template <class ELFT>
522Expected<const typename ELFT::Shdr *>
523ELFFile<ELFT>::getSection(const StringRef SectionName) const {
auto TableOrErr = sections();
if (!TableOrErr)
  return TableOrErr.takeError();
for (auto &Sec : *TableOrErr) {
  auto SecNameOrErr = getSectionName(&Sec);
  if (!SecNameOrErr)
    return SecNameOrErr.takeError();
  if (*SecNameOrErr == SectionName)
    return &Sec;
}
return createError("invalid section name");
535}

537template <class ELFT>
538Expected<StringRef>
539ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
if (Section->sh_type != ELF::SHT_STRTAB)
  return createError("invalid sh_type for string table, expected SHT_STRTAB");
auto V = getSectionContentsAsArray<char>(Section);
if (!V)
  return V.takeError();
ArrayRef<char> Data = *V;
if (Data.empty())
  return createError("empty string table");
if (Data.back() != '\0')
  return createError("string table non-null terminated");
return StringRef(Data.begin(), Data.size());
551}

553template <class ELFT>
554Expected<ArrayRef<typename ELFT::Word>>
555ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const {
auto SectionsOrErr = sections();
if (!SectionsOrErr)
  return SectionsOrErr.takeError();
return getSHNDXTable(Section, *SectionsOrErr);
560}

562template <class ELFT>
563Expected<ArrayRef<typename ELFT::Word>>
564ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section,
                           Elf_Shdr_Range Sections) const {
assert(Section.sh_type == ELF::SHT_SYMTAB_SHNDX)((Section.sh_type == ELF::SHT_SYMTAB_SHNDX) ? static_cast<
void> (0) : __assert_fail ("Section.sh_type == ELF::SHT_SYMTAB_SHNDX"
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Object/ELF.h"
, 566, __PRETTY_FUNCTION__));
auto VOrErr = getSectionContentsAsArray<Elf_Word>(&Section);
if (!VOrErr)
  return VOrErr.takeError();
ArrayRef<Elf_Word> V = *VOrErr;
auto SymTableOrErr = object::getSection<ELFT>(Sections, Section.sh_link);
if (!SymTableOrErr)
  return SymTableOrErr.takeError();
const Elf_Shdr &SymTable = **SymTableOrErr;
if (SymTable.sh_type != ELF::SHT_SYMTAB &&
    SymTable.sh_type != ELF::SHT_DYNSYM)
  return createError("invalid sh_type");
if (V.size() != (SymTable.sh_size / sizeof(Elf_Sym)))
  return createError("invalid section contents size");
return V;
581}

583template <class ELFT>
584Expected<StringRef>
585ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const {
auto SectionsOrErr = sections();
if (!SectionsOrErr)
  return SectionsOrErr.takeError();
return getStringTableForSymtab(Sec, *SectionsOrErr);
590}

592template <class ELFT>
593Expected<StringRef>
594ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec,
                                     Elf_Shdr_Range Sections) const {

if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM)
  return createError(
      "invalid sh_type for symbol table, expected SHT_SYMTAB or SHT_DYNSYM");
auto SectionOrErr = object::getSection<ELFT>(Sections, Sec.sh_link);
if (!SectionOrErr)
  return SectionOrErr.takeError();
return getStringTable(*SectionOrErr);
604}

606template <class ELFT>
607Expected<StringRef>
608ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
auto SectionsOrErr = sections();
if (!SectionsOrErr)
  return SectionsOrErr.takeError();
auto Table = getSectionStringTable(*SectionsOrErr);
if (!Table)
  return Table.takeError();
return getSectionName(Section, *Table);
616}

618template <class ELFT>
619Expected<StringRef> ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section,
                                                StringRef DotShstrtab) const {
uint32_t Offset = Section->sh_name;
if (Offset == 0)
  return StringRef();
if (Offset >= DotShstrtab.size())
  return createError("invalid string offset");
return StringRef(DotShstrtab.data() + Offset);
627}

629/// This function returns the hash value for a symbol in the .dynsym section
630/// Name of the API remains consistent as specified in the libelf
631/// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
632inline unsigned hashSysV(StringRef SymbolName) {
unsigned h = 0, g;
for (char C : SymbolName) {
  h = (h << 4) + C;
  g = h & 0xf0000000L;
  if (g != 0)
    h ^= g >> 24;
  h &= ~g;
}
return h;
642}

644} // end namespace object
645} // end namespace llvm

647#endif // LLVM_OBJECT_ELF_H

←

/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h

→

1//===- llvm/Support/Error.h - Recoverable error handling --------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines an API used to report recoverable errors.
10//
11//===----------------------------------------------------------------------===//
12 
13#ifndef LLVM_SUPPORT_ERROR_H
14#define LLVM_SUPPORT_ERROR_H
15 
16#include "llvm-c/Error.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/StringExtras.h"
20#include "llvm/ADT/Twine.h"
21#include "llvm/Config/abi-breaking.h"
22#include "llvm/Support/AlignOf.h"
23#include "llvm/Support/Compiler.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/ErrorHandling.h"
26#include "llvm/Support/ErrorOr.h"
27#include "llvm/Support/Format.h"
28#include "llvm/Support/raw_ostream.h"
29#include <algorithm>
30#include <cassert>
31#include <cstdint>
32#include <cstdlib>
33#include <functional>
34#include <memory>
35#include <new>
36#include <string>
37#include <system_error>
38#include <type_traits>
39#include <utility>
40#include <vector>
41 
42namespace llvm {
43 
44class ErrorSuccess;
45 
46/// Base class for error info classes. Do not extend this directly: Extend
47/// the ErrorInfo template subclass instead.
48class ErrorInfoBase {
49public:
50  virtual ~ErrorInfoBase() = default;
51 
52  /// Print an error message to an output stream.
53  virtual void log(raw_ostream &OS) const = 0;
54 
55  /// Return the error message as a string.
56  virtual std::string message() const {
57    std::string Msg;
58    raw_string_ostream OS(Msg);
59    log(OS);
60    return OS.str();
61  }
62 
63  /// Convert this error to a std::error_code.
64  ///
65  /// This is a temporary crutch to enable interaction with code still
66  /// using std::error_code. It will be removed in the future.
67  virtual std::error_code convertToErrorCode() const = 0;
68 
69  // Returns the class ID for this type.
70  static const void *classID() { return &ID; }
71 
72  // Returns the class ID for the dynamic type of this ErrorInfoBase instance.
73  virtual const void *dynamicClassID() const = 0;
74 
75  // Check whether this instance is a subclass of the class identified by
76  // ClassID.
77  virtual bool isA(const void *const ClassID) const {
78    return ClassID == classID();
79  }
80 
81  // Check whether this instance is a subclass of ErrorInfoT.
82  template <typename ErrorInfoT> bool isA() const {
83    return isA(ErrorInfoT::classID());
84  }
85 
86private:
87  virtual void anchor();
88 
89  static char ID;
90};
91 
92/// Lightweight error class with error context and mandatory checking.
93///
94/// Instances of this class wrap a ErrorInfoBase pointer. Failure states
95/// are represented by setting the pointer to a ErrorInfoBase subclass
96/// instance containing information describing the failure. Success is
97/// represented by a null pointer value.
98///
99/// Instances of Error also contains a 'Checked' flag, which must be set
100/// before the destructor is called, otherwise the destructor will trigger a
101/// runtime error. This enforces at runtime the requirement that all Error
102/// instances be checked or returned to the caller.
103///
104/// There are two ways to set the checked flag, depending on what state the
105/// Error instance is in. For Error instances indicating success, it
106/// is sufficient to invoke the boolean conversion operator. E.g.:
107///
108///   @code{.cpp}
109///   Error foo(<...>);
110///
111///   if (auto E = foo(<...>))
112///     return E; // <- Return E if it is in the error state.
113///   // We have verified that E was in the success state. It can now be safely
114///   // destroyed.
115///   @endcode
116///
117/// A success value *can not* be dropped. For example, just calling 'foo(<...>)'
118/// without testing the return value will raise a runtime error, even if foo
119/// returns success.
120///
121/// For Error instances representing failure, you must use either the
122/// handleErrors or handleAllErrors function with a typed handler. E.g.:
123///
124///   @code{.cpp}
125///   class MyErrorInfo : public ErrorInfo<MyErrorInfo> {
126///     // Custom error info.
127///   };
128///
129///   Error foo(<...>) { return make_error<MyErrorInfo>(...); }
130///
131///   auto E = foo(<...>); // <- foo returns failure with MyErrorInfo.
132///   auto NewE =
133///     handleErrors(E,
134///       [](const MyErrorInfo &M) {
135///         // Deal with the error.
136///       },
137///       [](std::unique_ptr<OtherError> M) -> Error {
138///         if (canHandle(*M)) {
139///           // handle error.
140///           return Error::success();
141///         }
142///         // Couldn't handle this error instance. Pass it up the stack.
143///         return Error(std::move(M));
144///       );
145///   // Note - we must check or return NewE in case any of the handlers
146///   // returned a new error.
147///   @endcode
148///
149/// The handleAllErrors function is identical to handleErrors, except
150/// that it has a void return type, and requires all errors to be handled and
151/// no new errors be returned. It prevents errors (assuming they can all be
152/// handled) from having to be bubbled all the way to the top-level.
153///
154/// *All* Error instances must be checked before destruction, even if
155/// they're moved-assigned or constructed from Success values that have already
156/// been checked. This enforces checking through all levels of the call stack.
157class LLVM_NODISCARD[[clang::warn_unused_result]] Error {
158  // Both ErrorList and FileError need to be able to yank ErrorInfoBase
159  // pointers out of this class to add to the error list.
160  friend class ErrorList;
161  friend class FileError;
162 
163  // handleErrors needs to be able to set the Checked flag.
164  template <typename... HandlerTs>
165  friend Error handleErrors(Error E, HandlerTs &&... Handlers);
166 
167  // Expected<T> needs to be able to steal the payload when constructed from an
168  // error.
169  template <typename T> friend class Expected;
170 
171  // wrap needs to be able to steal the payload.
172  friend LLVMErrorRef wrap(Error);
173 
174protected:
175  /// Create a success value. Prefer using 'Error::success()' for readability
176  Error() {
177    setPtr(nullptr);
178    setChecked(false);
179  }
180 
181public:
182  /// Create a success value.
183  static ErrorSuccess success();
184 
185  // Errors are not copy-constructable.
186  Error(const Error &Other) = delete;
187 
188  /// Move-construct an error value. The newly constructed error is considered
189  /// unchecked, even if the source error had been checked. The original error
190  /// becomes a checked Success value, regardless of its original state.
191  Error(Error &&Other) {
192    setChecked(true);
193    *this = std::move(Other);
194  }
195 
196  /// Create an error value. Prefer using the 'make_error' function, but
197  /// this constructor can be useful when "re-throwing" errors from handlers.
198  Error(std::unique_ptr<ErrorInfoBase> Payload) {
199    setPtr(Payload.release());
200    setChecked(false);
12
←
Potential leak of memory pointed to by 'Payload._M_t._M_head_impl'
201  }
202 
203  // Errors are not copy-assignable.
204  Error &operator=(const Error &Other) = delete;
205 
206  /// Move-assign an error value. The current error must represent success, you
207  /// you cannot overwrite an unhandled error. The current error is then
208  /// considered unchecked. The source error becomes a checked success value,
209  /// regardless of its original state.
210  Error &operator=(Error &&Other) {
211    // Don't allow overwriting of unchecked values.
212    assertIsChecked();
213    setPtr(Other.getPtr());
214 
215    // This Error is unchecked, even if the source error was checked.
216    setChecked(false);
217 
218    // Null out Other's payload and set its checked bit.
219    Other.setPtr(nullptr);
220    Other.setChecked(true);
221 
222    return *this;
223  }
224 
225  /// Destroy a Error. Fails with a call to abort() if the error is
226  /// unchecked.
227  ~Error() {
228    assertIsChecked();
229    delete getPtr();
230  }
231 
232  /// Bool conversion. Returns true if this Error is in a failure state,
233  /// and false if it is in an accept state. If the error is in a Success state
234  /// it will be considered checked.
235  explicit operator bool() {
236    setChecked(getPtr() == nullptr);
237    return getPtr() != nullptr;
238  }
239 
240  /// Check whether one error is a subclass of another.
241  template <typename ErrT> bool isA() const {
242    return getPtr() && getPtr()->isA(ErrT::classID());
243  }
244 
245  /// Returns the dynamic class id of this error, or null if this is a success
246  /// value.
247  const void* dynamicClassID() const {
248    if (!getPtr())
249      return nullptr;
250    return getPtr()->dynamicClassID();
251  }
252 
253private:
254#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
255  // assertIsChecked() happens very frequently, but under normal circumstances
256  // is supposed to be a no-op.  So we want it to be inlined, but having a bunch
257  // of debug prints can cause the function to be too large for inlining.  So
258  // it's important that we define this function out of line so that it can't be
259  // inlined.
260  LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
261  void fatalUncheckedError() const;
262#endif
263 
264  void assertIsChecked() {
265#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
266    if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false))
267      fatalUncheckedError();
268#endif
269  }
270 
271  ErrorInfoBase *getPtr() const {
272    return reinterpret_cast<ErrorInfoBase*>(
273             reinterpret_cast<uintptr_t>(Payload) &
274             ~static_cast<uintptr_t>(0x1));
275  }
276 
277  void setPtr(ErrorInfoBase *EI) {
278#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
279    Payload = reinterpret_cast<ErrorInfoBase*>(
280                (reinterpret_cast<uintptr_t>(EI) &
281                 ~static_cast<uintptr_t>(0x1)) |
282                (reinterpret_cast<uintptr_t>(Payload) & 0x1));
283#else
284    Payload = EI;
285#endif
286  }
287 
288  bool getChecked() const {
289#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
290    return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0;
291#else
292    return true;
293#endif
294  }
295 
296  void setChecked(bool V) {
297    Payload = reinterpret_cast<ErrorInfoBase*>(
298                (reinterpret_cast<uintptr_t>(Payload) &
299                  ~static_cast<uintptr_t>(0x1)) |
300                  (V ? 0 : 1));
301  }
302 
303  std::unique_ptr<ErrorInfoBase> takePayload() {
304    std::unique_ptr<ErrorInfoBase> Tmp(getPtr());
305    setPtr(nullptr);
306    setChecked(true);
307    return Tmp;
308  }
309 
310  friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) {
311    if (auto P = E.getPtr())
312      P->log(OS);
313    else
314      OS << "success";
315    return OS;
316  }
317 
318  ErrorInfoBase *Payload = nullptr;
319};
320 
321/// Subclass of Error for the sole purpose of identifying the success path in
322/// the type system. This allows to catch invalid conversion to Expected<T> at
323/// compile time.
324class ErrorSuccess final : public Error {};
325 
326inline ErrorSuccess Error::success() { return ErrorSuccess(); }
327 
328/// Make a Error instance representing failure using the given error info
329/// type.
330template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) {
331  return Error(llvm::make_unique<ErrT>(std::forward<ArgTs>(Args)...));
8
←
Calling 'make_unique<llvm::StringError, llvm::StringRef &, llvm::object::object_error>'→
10
←
Returned allocated memory→
11
←
Calling constructor for 'Error'→
332}
333 
334/// Base class for user error types. Users should declare their error types
335/// like:
336///
337/// class MyError : public ErrorInfo<MyError> {
338///   ....
339/// };
340///
341/// This class provides an implementation of the ErrorInfoBase::kind
342/// method, which is used by the Error RTTI system.
343template <typename ThisErrT, typename ParentErrT = ErrorInfoBase>
344class ErrorInfo : public ParentErrT {
345public:
346  using ParentErrT::ParentErrT; // inherit constructors
347 
348  static const void *classID() { return &ThisErrT::ID; }
349 
350  const void *dynamicClassID() const override { return &ThisErrT::ID; }
351 
352  bool isA(const void *const ClassID) const override {
353    return ClassID == classID() || ParentErrT::isA(ClassID);
354  }
355};
356 
357/// Special ErrorInfo subclass representing a list of ErrorInfos.
358/// Instances of this class are constructed by joinError.
359class ErrorList final : public ErrorInfo<ErrorList> {
360  // handleErrors needs to be able to iterate the payload list of an
361  // ErrorList.
362  template <typename... HandlerTs>
363  friend Error handleErrors(Error E, HandlerTs &&... Handlers);
364 
365  // joinErrors is implemented in terms of join.
366  friend Error joinErrors(Error, Error);
367 
368public:
369  void log(raw_ostream &OS) const override {
370    OS << "Multiple errors:\n";
371    for (auto &ErrPayload : Payloads) {
372      ErrPayload->log(OS);
373      OS << "\n";
374    }
375  }
376 
377  std::error_code convertToErrorCode() const override;
378 
379  // Used by ErrorInfo::classID.
380  static char ID;
381 
382private:
383  ErrorList(std::unique_ptr<ErrorInfoBase> Payload1,
384            std::unique_ptr<ErrorInfoBase> Payload2) {
385    assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 386, __PRETTY_FUNCTION__))
386           "ErrorList constructor payloads should be singleton errors")((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 386, __PRETTY_FUNCTION__));
387    Payloads.push_back(std::move(Payload1));
388    Payloads.push_back(std::move(Payload2));
389  }
390 
391  static Error join(Error E1, Error E2) {
392    if (!E1)
393      return E2;
394    if (!E2)
395      return E1;
396    if (E1.isA<ErrorList>()) {
397      auto &E1List = static_cast<ErrorList &>(*E1.getPtr());
398      if (E2.isA<ErrorList>()) {
399        auto E2Payload = E2.takePayload();
400        auto &E2List = static_cast<ErrorList &>(*E2Payload);
401        for (auto &Payload : E2List.Payloads)
402          E1List.Payloads.push_back(std::move(Payload));
403      } else
404        E1List.Payloads.push_back(E2.takePayload());
405 
406      return E1;
407    }
408    if (E2.isA<ErrorList>()) {
409      auto &E2List = static_cast<ErrorList &>(*E2.getPtr());
410      E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload());
411      return E2;
412    }
413    return Error(std::unique_ptr<ErrorList>(
414        new ErrorList(E1.takePayload(), E2.takePayload())));
415  }
416 
417  std::vector<std::unique_ptr<ErrorInfoBase>> Payloads;
418};
419 
420/// Concatenate errors. The resulting Error is unchecked, and contains the
421/// ErrorInfo(s), if any, contained in E1, followed by the
422/// ErrorInfo(s), if any, contained in E2.
423inline Error joinErrors(Error E1, Error E2) {
424  return ErrorList::join(std::move(E1), std::move(E2));
425}
426 
427/// Tagged union holding either a T or a Error.
428///
429/// This class parallels ErrorOr, but replaces error_code with Error. Since
430/// Error cannot be copied, this class replaces getError() with
431/// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the
432/// error class type.
433template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected {
434  template <class T1> friend class ExpectedAsOutParameter;
435  template <class OtherT> friend class Expected;
436 
437  static const bool isRef = std::is_reference<T>::value;
438 
439  using wrap = std::reference_wrapper<typename std::remove_reference<T>::type>;
440 
441  using error_type = std::unique_ptr<ErrorInfoBase>;
442 
443public:
444  using storage_type = typename std::conditional<isRef, wrap, T>::type;
445  using value_type = T;
446 
447private:
448  using reference = typename std::remove_reference<T>::type &;
449  using const_reference = const typename std::remove_reference<T>::type &;
450  using pointer = typename std::remove_reference<T>::type *;
451  using const_pointer = const typename std::remove_reference<T>::type *;
452 
453public:
454  /// Create an Expected<T> error value from the given Error.
455  Expected(Error Err)
456      : HasError(true)
457#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
458        // Expected is unchecked upon construction in Debug builds.
459        , Unchecked(true)
460#endif
461  {
462    assert(Err && "Cannot create Expected<T> from Error success value.")((Err && "Cannot create Expected<T> from Error success value."
) ? static_cast<void> (0) : __assert_fail ("Err && \"Cannot create Expected<T> from Error success value.\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 462, __PRETTY_FUNCTION__));
463    new (getErrorStorage()) error_type(Err.takePayload());
464  }
465 
466  /// Forbid to convert from Error::success() implicitly, this avoids having
467  /// Expected<T> foo() { return Error::success(); } which compiles otherwise
468  /// but triggers the assertion above.
469  Expected(ErrorSuccess) = delete;
470 
471  /// Create an Expected<T> success value from the given OtherT value, which
472  /// must be convertible to T.
473  template <typename OtherT>
474  Expected(OtherT &&Val,
475           typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
476               * = nullptr)
477      : HasError(false)
478#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
479        // Expected is unchecked upon construction in Debug builds.
480        , Unchecked(true)
481#endif
482  {
483    new (getStorage()) storage_type(std::forward<OtherT>(Val));
484  }
485 
486  /// Move construct an Expected<T> value.
487  Expected(Expected &&Other) { moveConstruct(std::move(Other)); }
488 
489  /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
490  /// must be convertible to T.
491  template <class OtherT>
492  Expected(Expected<OtherT> &&Other,
493           typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
494               * = nullptr) {
495    moveConstruct(std::move(Other));
496  }
497 
498  /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
499  /// isn't convertible to T.
500  template <class OtherT>
501  explicit Expected(
502      Expected<OtherT> &&Other,
503      typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * =
504          nullptr) {
505    moveConstruct(std::move(Other));
506  }
507 
508  /// Move-assign from another Expected<T>.
509  Expected &operator=(Expected &&Other) {
510    moveAssign(std::move(Other));
511    return *this;
512  }
513 
514  /// Destroy an Expected<T>.
515  ~Expected() {
516    assertIsChecked();
517    if (!HasError)
518      getStorage()->~storage_type();
519    else
520      getErrorStorage()->~error_type();
521  }
522 
523  /// Return false if there is an error.
524  explicit operator bool() {
525#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
526    Unchecked = HasError;
527#endif
528    return !HasError;
529  }
530 
531  /// Returns a reference to the stored T value.
532  reference get() {
533    assertIsChecked();
534    return *getStorage();
535  }
536 
537  /// Returns a const reference to the stored T value.
538  const_reference get() const {
539    assertIsChecked();
540    return const_cast<Expected<T> *>(this)->get();
541  }
542 
543  /// Check that this Expected<T> is an error of type ErrT.
544  template <typename ErrT> bool errorIsA() const {
545    return HasError && (*getErrorStorage())->template isA<ErrT>();
546  }
547 
548  /// Take ownership of the stored error.
549  /// After calling this the Expected<T> is in an indeterminate state that can
550  /// only be safely destructed. No further calls (beside the destructor) should
551  /// be made on the Expected<T> vaule.
552  Error takeError() {
553#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
554    Unchecked = false;
555#endif
556    return HasError ? Error(std::move(*getErrorStorage())) : Error::success();
557  }
558 
559  /// Returns a pointer to the stored T value.
560  pointer operator->() {
561    assertIsChecked();
562    return toPointer(getStorage());
563  }
564 
565  /// Returns a const pointer to the stored T value.
566  const_pointer operator->() const {
567    assertIsChecked();
568    return toPointer(getStorage());
569  }
570 
571  /// Returns a reference to the stored T value.
572  reference operator*() {
573    assertIsChecked();
574    return *getStorage();
575  }
576 
577  /// Returns a const reference to the stored T value.
578  const_reference operator*() const {
579    assertIsChecked();
580    return *getStorage();
581  }
582 
583private:
584  template <class T1>
585  static bool compareThisIfSameType(const T1 &a, const T1 &b) {
586    return &a == &b;
587  }
588 
589  template <class T1, class T2>
590  static bool compareThisIfSameType(const T1 &a, const T2 &b) {
591    return false;
592  }
593 
594  template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) {
595    HasError = Other.HasError;
596#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
597    Unchecked = true;
598    Other.Unchecked = false;
599#endif
600 
601    if (!HasError)
602      new (getStorage()) storage_type(std::move(*Other.getStorage()));
603    else
604      new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage()));
605  }
606 
607  template <class OtherT> void moveAssign(Expected<OtherT> &&Other) {
608    assertIsChecked();
609 
610    if (compareThisIfSameType(*this, Other))
611      return;
612 
613    this->~Expected();
614    new (this) Expected(std::move(Other));
615  }
616 
617  pointer toPointer(pointer Val) { return Val; }
618 
619  const_pointer toPointer(const_pointer Val) const { return Val; }
620 
621  pointer toPointer(wrap *Val) { return &Val->get(); }
622 
623  const_pointer toPointer(const wrap *Val) const { return &Val->get(); }
624 
625  storage_type *getStorage() {
626    assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 626, __PRETTY_FUNCTION__));
627    return reinterpret_cast<storage_type *>(TStorage.buffer);
628  }
629 
630  const storage_type *getStorage() const {
631    assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 631, __PRETTY_FUNCTION__));
632    return reinterpret_cast<const storage_type *>(TStorage.buffer);
633  }
634 
635  error_type *getErrorStorage() {
636    assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 636, __PRETTY_FUNCTION__));
637    return reinterpret_cast<error_type *>(ErrorStorage.buffer);
638  }
639 
640  const error_type *getErrorStorage() const {
641    assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 641, __PRETTY_FUNCTION__));
642    return reinterpret_cast<const error_type *>(ErrorStorage.buffer);
643  }
644 
645  // Used by ExpectedAsOutParameter to reset the checked flag.
646  void setUnchecked() {
647#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
648    Unchecked = true;
649#endif
650  }
651 
652#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
653  LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
654  LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline))
655  void fatalUncheckedExpected() const {
656    dbgs() << "Expected<T> must be checked before access or destruction.\n";
657    if (HasError) {
658      dbgs() << "Unchecked Expected<T> contained error:\n";
659      (*getErrorStorage())->log(dbgs());
660    } else
661      dbgs() << "Expected<T> value was in success state. (Note: Expected<T> "
662                "values in success mode must still be checked prior to being "
663                "destroyed).\n";
664    abort();
665  }
666#endif
667 
668  void assertIsChecked() {
669#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
670    if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false))
671      fatalUncheckedExpected();
672#endif
673  }
674 
675  union {
676    AlignedCharArrayUnion<storage_type> TStorage;
677    AlignedCharArrayUnion<error_type> ErrorStorage;
678  };
679  bool HasError : 1;
680#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
681  bool Unchecked : 1;
682#endif
683};
684 
685/// Report a serious error, calling any installed error handler. See
686/// ErrorHandling.h.
687LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) void report_fatal_error(Error Err,
688                                                bool gen_crash_diag = true);
689 
690/// Report a fatal error if Err is a failure value.
691///
692/// This function can be used to wrap calls to fallible functions ONLY when it
693/// is known that the Error will always be a success value. E.g.
694///
695///   @code{.cpp}
696///   // foo only attempts the fallible operation if DoFallibleOperation is
697///   // true. If DoFallibleOperation is false then foo always returns
698///   // Error::success().
699///   Error foo(bool DoFallibleOperation);
700///
701///   cantFail(foo(false));
702///   @endcode
703inline void cantFail(Error Err, const char *Msg = nullptr) {
704  if (Err) {
705    if (!Msg)
706      Msg = "Failure value returned from cantFail wrapped call";
707    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 707);
708  }
709}
710 
711/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
712/// returns the contained value.
713///
714/// This function can be used to wrap calls to fallible functions ONLY when it
715/// is known that the Error will always be a success value. E.g.
716///
717///   @code{.cpp}
718///   // foo only attempts the fallible operation if DoFallibleOperation is
719///   // true. If DoFallibleOperation is false then foo always returns an int.
720///   Expected<int> foo(bool DoFallibleOperation);
721///
722///   int X = cantFail(foo(false));
723///   @endcode
724template <typename T>
725T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) {
726  if (ValOrErr)
727    return std::move(*ValOrErr);
728  else {
729    if (!Msg)
730      Msg = "Failure value returned from cantFail wrapped call";
731    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 731);
732  }
733}
734 
735/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
736/// returns the contained reference.
737///
738/// This function can be used to wrap calls to fallible functions ONLY when it
739/// is known that the Error will always be a success value. E.g.
740///
741///   @code{.cpp}
742///   // foo only attempts the fallible operation if DoFallibleOperation is
743///   // true. If DoFallibleOperation is false then foo always returns a Bar&.
744///   Expected<Bar&> foo(bool DoFallibleOperation);
745///
746///   Bar &X = cantFail(foo(false));
747///   @endcode
748template <typename T>
749T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) {
750  if (ValOrErr)
751    return *ValOrErr;
752  else {
753    if (!Msg)
754      Msg = "Failure value returned from cantFail wrapped call";
755    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 755);
756  }
757}
758 
759/// Helper for testing applicability of, and applying, handlers for
760/// ErrorInfo types.
761template <typename HandlerT>
762class ErrorHandlerTraits
763    : public ErrorHandlerTraits<decltype(
764          &std::remove_reference<HandlerT>::type::operator())> {};
765 
766// Specialization functions of the form 'Error (const ErrT&)'.
767template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> {
768public:
769  static bool appliesTo(const ErrorInfoBase &E) {
770    return E.template isA<ErrT>();
771  }
772 
773  template <typename HandlerT>
774  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
775    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 775, __PRETTY_FUNCTION__));
776    return H(static_cast<ErrT &>(*E));
777  }
778};
779 
780// Specialization functions of the form 'void (const ErrT&)'.
781template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> {
782public:
783  static bool appliesTo(const ErrorInfoBase &E) {
784    return E.template isA<ErrT>();
785  }
786 
787  template <typename HandlerT>
788  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
789    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 789, __PRETTY_FUNCTION__));
790    H(static_cast<ErrT &>(*E));
791    return Error::success();
792  }
793};
794 
795/// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'.
796template <typename ErrT>
797class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> {
798public:
799  static bool appliesTo(const ErrorInfoBase &E) {
800    return E.template isA<ErrT>();
801  }
802 
803  template <typename HandlerT>
804  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
805    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 805, __PRETTY_FUNCTION__));
806    std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
807    return H(std::move(SubE));
808  }
809};
810 
811/// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'.
812template <typename ErrT>
813class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> {
814public:
815  static bool appliesTo(const ErrorInfoBase &E) {
816    return E.template isA<ErrT>();
817  }
818 
819  template <typename HandlerT>
820  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
821    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 821, __PRETTY_FUNCTION__));
822    std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
823    H(std::move(SubE));
824    return Error::success();
825  }
826};
827 
828// Specialization for member functions of the form 'RetT (const ErrT&)'.
829template <typename C, typename RetT, typename ErrT>
830class ErrorHandlerTraits<RetT (C::*)(ErrT &)>
831    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
832 
833// Specialization for member functions of the form 'RetT (const ErrT&) const'.
834template <typename C, typename RetT, typename ErrT>
835class ErrorHandlerTraits<RetT (C::*)(ErrT &) const>
836    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
837 
838// Specialization for member functions of the form 'RetT (const ErrT&)'.
839template <typename C, typename RetT, typename ErrT>
840class ErrorHandlerTraits<RetT (C::*)(const ErrT &)>
841    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
842 
843// Specialization for member functions of the form 'RetT (const ErrT&) const'.
844template <typename C, typename RetT, typename ErrT>
845class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const>
846    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
847 
848/// Specialization for member functions of the form
849/// 'RetT (std::unique_ptr<ErrT>)'.
850template <typename C, typename RetT, typename ErrT>
851class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)>
852    : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
853 
854/// Specialization for member functions of the form
855/// 'RetT (std::unique_ptr<ErrT>) const'.
856template <typename C, typename RetT, typename ErrT>
857class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const>
858    : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
859 
860inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) {
861  return Error(std::move(Payload));
862}
863 
864template <typename HandlerT, typename... HandlerTs>
865Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload,
866                      HandlerT &&Handler, HandlerTs &&... Handlers) {
867  if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload))
868    return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler),
869                                               std::move(Payload));
870  return handleErrorImpl(std::move(Payload),
871                         std::forward<HandlerTs>(Handlers)...);
872}
873 
874/// Pass the ErrorInfo(s) contained in E to their respective handlers. Any
875/// unhandled errors (or Errors returned by handlers) are re-concatenated and
876/// returned.
877/// Because this function returns an error, its result must also be checked
878/// or returned. If you intend to handle all errors use handleAllErrors
879/// (which returns void, and will abort() on unhandled errors) instead.
880template <typename... HandlerTs>
881Error handleErrors(Error E, HandlerTs &&... Hs) {
882  if (!E)
883    return Error::success();
884 
885  std::unique_ptr<ErrorInfoBase> Payload = E.takePayload();
886 
887  if (Payload->isA<ErrorList>()) {
888    ErrorList &List = static_cast<ErrorList &>(*Payload);
889    Error R;
890    for (auto &P : List.Payloads)
891      R = ErrorList::join(
892          std::move(R),
893          handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...));
894    return R;
895  }
896 
897  return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...);
898}
899 
900/// Behaves the same as handleErrors, except that by contract all errors
901/// *must* be handled by the given handlers (i.e. there must be no remaining
902/// errors after running the handlers, or llvm_unreachable is called).
903template <typename... HandlerTs>
904void handleAllErrors(Error E, HandlerTs &&... Handlers) {
905  cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...));
906}
907 
908/// Check that E is a non-error, then drop it.
909/// If E is an error, llvm_unreachable will be called.
910inline void handleAllErrors(Error E) {
911  cantFail(std::move(E));
912}
913 
914/// Handle any errors (if present) in an Expected<T>, then try a recovery path.
915///
916/// If the incoming value is a success value it is returned unmodified. If it
917/// is a failure value then it the contained error is passed to handleErrors.
918/// If handleErrors is able to handle the error then the RecoveryPath functor
919/// is called to supply the final result. If handleErrors is not able to
920/// handle all errors then the unhandled errors are returned.
921///
922/// This utility enables the follow pattern:
923///
924///   @code{.cpp}
925///   enum FooStrategy { Aggressive, Conservative };
926///   Expected<Foo> foo(FooStrategy S);
927///
928///   auto ResultOrErr =
929///     handleExpected(
930///       foo(Aggressive),
931///       []() { return foo(Conservative); },
932///       [](AggressiveStrategyError&) {
933///         // Implicitly conusme this - we'll recover by using a conservative
934///         // strategy.
935///       });
936///
937///   @endcode
938template <typename T, typename RecoveryFtor, typename... HandlerTs>
939Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath,
940                           HandlerTs &&... Handlers) {
941  if (ValOrErr)
942    return ValOrErr;
943 
944  if (auto Err = handleErrors(ValOrErr.takeError(),
945                              std::forward<HandlerTs>(Handlers)...))
946    return std::move(Err);
947 
948  return RecoveryPath();
949}
950 
951/// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner
952/// will be printed before the first one is logged. A newline will be printed
953/// after each error.
954///
955/// This function is compatible with the helpers from Support/WithColor.h. You
956/// can pass any of them as the OS. Please consider using them instead of
957/// including 'error: ' in the ErrorBanner.
958///
959/// This is useful in the base level of your program to allow clean termination
960/// (allowing clean deallocation of resources, etc.), while reporting error
961/// information to the user.
962void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {});
963 
964/// Write all error messages (if any) in E to a string. The newline character
965/// is used to separate error messages.
966inline std::string toString(Error E) {
967  SmallVector<std::string, 2> Errors;
968  handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) {
969    Errors.push_back(EI.message());
970  });
971  return join(Errors.begin(), Errors.end(), "\n");
972}
973 
974/// Consume a Error without doing anything. This method should be used
975/// only where an error can be considered a reasonable and expected return
976/// value.
977///
978/// Uses of this method are potentially indicative of design problems: If it's
979/// legitimate to do nothing while processing an "error", the error-producer
980/// might be more clearly refactored to return an Optional<T>.
981inline void consumeError(Error Err) {
982  handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {});
983}
984 
985/// Helper for converting an Error to a bool.
986///
987/// This method returns true if Err is in an error state, or false if it is
988/// in a success state.  Puts Err in a checked state in both cases (unlike
989/// Error::operator bool(), which only does this for success states).
990inline bool errorToBool(Error Err) {
991  bool IsError = static_cast<bool>(Err);
992  if (IsError)
993    consumeError(std::move(Err));
994  return IsError;
995}
996 
997/// Helper for Errors used as out-parameters.
998///
999/// This helper is for use with the Error-as-out-parameter idiom, where an error
1000/// is passed to a function or method by reference, rather than being returned.
1001/// In such cases it is helpful to set the checked bit on entry to the function
1002/// so that the error can be written to (unchecked Errors abort on assignment)
1003/// and clear the checked bit on exit so that clients cannot accidentally forget
1004/// to check the result. This helper performs these actions automatically using
1005/// RAII:
1006///
1007///   @code{.cpp}
1008///   Result foo(Error &Err) {
1009///     ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set
1010///     // <body of foo>
1011///     // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed.
1012///   }
1013///   @endcode
1014///
1015/// ErrorAsOutParameter takes an Error* rather than Error& so that it can be
1016/// used with optional Errors (Error pointers that are allowed to be null). If
1017/// ErrorAsOutParameter took an Error reference, an instance would have to be
1018/// created inside every condition that verified that Error was non-null. By
1019/// taking an Error pointer we can just create one instance at the top of the
1020/// function.
1021class ErrorAsOutParameter {
1022public:
1023  ErrorAsOutParameter(Error *Err) : Err(Err) {
1024    // Raise the checked bit if Err is success.
1025    if (Err)
1026      (void)!!*Err;
1027  }
1028 
1029  ~ErrorAsOutParameter() {
1030    // Clear the checked bit.
1031    if (Err && !*Err)
1032      *Err = Error::success();
1033  }
1034 
1035private:
1036  Error *Err;
1037};
1038 
1039/// Helper for Expected<T>s used as out-parameters.
1040///
1041/// See ErrorAsOutParameter.
1042template <typename T>
1043class ExpectedAsOutParameter {
1044public:
1045  ExpectedAsOutParameter(Expected<T> *ValOrErr)
1046    : ValOrErr(ValOrErr) {
1047    if (ValOrErr)
1048      (void)!!*ValOrErr;
1049  }
1050 
1051  ~ExpectedAsOutParameter() {
1052    if (ValOrErr)
1053      ValOrErr->setUnchecked();
1054  }
1055 
1056private:
1057  Expected<T> *ValOrErr;
1058};
1059 
1060/// This class wraps a std::error_code in a Error.
1061///
1062/// This is useful if you're writing an interface that returns a Error
1063/// (or Expected) and you want to call code that still returns
1064/// std::error_codes.
1065class ECError : public ErrorInfo<ECError> {
1066  friend Error errorCodeToError(std::error_code);
1067 
1068  virtual void anchor() override;
1069 
1070public:
1071  void setErrorCode(std::error_code EC) { this->EC = EC; }
1072  std::error_code convertToErrorCode() const override { return EC; }
1073  void log(raw_ostream &OS) const override { OS << EC.message(); }
1074 
1075  // Used by ErrorInfo::classID.
1076  static char ID;
1077 
1078protected:
1079  ECError() = default;
1080  ECError(std::error_code EC) : EC(EC) {}
1081 
1082  std::error_code EC;
1083};
1084 
1085/// The value returned by this function can be returned from convertToErrorCode
1086/// for Error values where no sensible translation to std::error_code exists.
1087/// It should only be used in this situation, and should never be used where a
1088/// sensible conversion to std::error_code is available, as attempts to convert
1089/// to/from this error will result in a fatal error. (i.e. it is a programmatic
1090///error to try to convert such a value).
1091std::error_code inconvertibleErrorCode();
1092 
1093/// Helper for converting an std::error_code to a Error.
1094Error errorCodeToError(std::error_code EC);
1095 
1096/// Helper for converting an ECError to a std::error_code.
1097///
1098/// This method requires that Err be Error() or an ECError, otherwise it
1099/// will trigger a call to abort().
1100std::error_code errorToErrorCode(Error Err);
1101 
1102/// Convert an ErrorOr<T> to an Expected<T>.
1103template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) {
1104  if (auto EC = EO.getError())
1105    return errorCodeToError(EC);
1106  return std::move(*EO);
1107}
1108 
1109/// Convert an Expected<T> to an ErrorOr<T>.
1110template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) {
1111  if (auto Err = E.takeError())
1112    return errorToErrorCode(std::move(Err));
1113  return std::move(*E);
1114}
1115 
1116/// This class wraps a string in an Error.
1117///
1118/// StringError is useful in cases where the client is not expected to be able
1119/// to consume the specific error message programmatically (for example, if the
1120/// error message is to be presented to the user).
1121///
1122/// StringError can also be used when additional information is to be printed
1123/// along with a error_code message. Depending on the constructor called, this
1124/// class can either display:
1125///    1. the error_code message (ECError behavior)
1126///    2. a string
1127///    3. the error_code message and a string
1128///
1129/// These behaviors are useful when subtyping is required; for example, when a
1130/// specific library needs an explicit error type. In the example below,
1131/// PDBError is derived from StringError:
1132///
1133///   @code{.cpp}
1134///   Expected<int> foo() {
1135///      return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading,
1136///                                        "Additional information");
1137///   }
1138///   @endcode
1139///
1140class StringError : public ErrorInfo<StringError> {
1141public:
1142  static char ID;
1143 
1144  // Prints EC + S and converts to EC
1145  StringError(std::error_code EC, const Twine &S = Twine());
1146 
1147  // Prints S and converts to EC
1148  StringError(const Twine &S, std::error_code EC);
1149 
1150  void log(raw_ostream &OS) const override;
1151  std::error_code convertToErrorCode() const override;
1152 
1153  const std::string &getMessage() const { return Msg; }
1154 
1155private:
1156  std::string Msg;
1157  std::error_code EC;
1158  const bool PrintMsgOnly = false;
1159};
1160 
1161/// Create formatted StringError object.
1162template <typename... Ts>
1163Error createStringError(std::error_code EC, char const *Fmt,
1164                        const Ts &... Vals) {
1165  std::string Buffer;
1166  raw_string_ostream Stream(Buffer);
1167  Stream << format(Fmt, Vals...);
1168  return make_error<StringError>(Stream.str(), EC);
1169}
1170 
1171Error createStringError(std::error_code EC, char const *Msg);
1172 
1173/// This class wraps a filename and another Error.
1174///
1175/// In some cases, an error needs to live along a 'source' name, in order to
1176/// show more detailed information to the user.
1177class FileError final : public ErrorInfo<FileError> {
1178 
1179  friend Error createFileError(const Twine &, Error);
1180  friend Error createFileError(const Twine &, size_t, Error);
1181 
1182public:
1183  void log(raw_ostream &OS) const override {
1184    assert(Err && !FileName.empty() && "Trying to log after takeError().")((Err && !FileName.empty() && "Trying to log after takeError()."
) ? static_cast<void> (0) : __assert_fail ("Err && !FileName.empty() && \"Trying to log after takeError().\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 1184, __PRETTY_FUNCTION__));
1185    OS << "'" << FileName << "': ";
1186    if (Line.hasValue())
1187      OS << "line " << Line.getValue() << ": ";
1188    Err->log(OS);
1189  }
1190 
1191  Error takeError() { return Error(std::move(Err)); }
1192 
1193  std::error_code convertToErrorCode() const override;
1194 
1195  // Used by ErrorInfo::classID.
1196  static char ID;
1197 
1198private:
1199  FileError(const Twine &F, Optional<size_t> LineNum,
1200            std::unique_ptr<ErrorInfoBase> E) {
1201    assert(E && "Cannot create FileError from Error success value.")((E && "Cannot create FileError from Error success value."
) ? static_cast<void> (0) : __assert_fail ("E && \"Cannot create FileError from Error success value.\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 1201, __PRETTY_FUNCTION__));
1202    assert(!F.isTriviallyEmpty() &&((!F.isTriviallyEmpty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.isTriviallyEmpty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 1203, __PRETTY_FUNCTION__))
1203           "The file name provided to FileError must not be empty.")((!F.isTriviallyEmpty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.isTriviallyEmpty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/Support/Error.h"
, 1203, __PRETTY_FUNCTION__));
1204    FileName = F.str();
1205    Err = std::move(E);
1206    Line = std::move(LineNum);
1207  }
1208 
1209  static Error build(const Twine &F, Optional<size_t> Line, Error E) {
1210    return Error(
1211        std::unique_ptr<FileError>(new FileError(F, Line, E.takePayload())));
1212  }
1213 
1214  std::string FileName;
1215  Optional<size_t> Line;
1216  std::unique_ptr<ErrorInfoBase> Err;
1217};
1218 
1219/// Concatenate a source file path and/or name with an Error. The resulting
1220/// Error is unchecked.
1221inline Error createFileError(const Twine &F, Error E) {
1222  return FileError::build(F, Optional<size_t>(), std::move(E));
1223}
1224 
1225/// Concatenate a source file path and/or name with line number and an Error.
1226/// The resulting Error is unchecked.
1227inline Error createFileError(const Twine &F, size_t Line, Error E) {
1228  return FileError::build(F, Optional<size_t>(Line), std::move(E));
1229}
1230 
1231/// Concatenate a source file path and/or name with a std::error_code 
1232/// to form an Error object.
1233inline Error createFileError(const Twine &F, std::error_code EC) {
1234  return createFileError(F, errorCodeToError(EC));
1235}
1236 
1237/// Concatenate a source file path and/or name with line number and
1238/// std::error_code to form an Error object.
1239inline Error createFileError(const Twine &F, size_t Line, std::error_code EC) {
1240  return createFileError(F, Line, errorCodeToError(EC));
1241}
1242 
1243Error createFileError(const Twine &F, ErrorSuccess) = delete;
1244 
1245/// Helper for check-and-exit error handling.
1246///
1247/// For tool use only. NOT FOR USE IN LIBRARY CODE.
1248///
1249class ExitOnError {
1250public:
1251  /// Create an error on exit helper.
1252  ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1)
1253      : Banner(std::move(Banner)),
1254        GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {}
1255 
1256  /// Set the banner string for any errors caught by operator().
1257  void setBanner(std::string Banner) { this->Banner = std::move(Banner); }
1258 
1259  /// Set the exit-code mapper function.
1260  void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) {
1261    this->GetExitCode = std::move(GetExitCode);
1262  }
1263 
1264  /// Check Err. If it's in a failure state log the error(s) and exit.
1265  void operator()(Error Err) const { checkError(std::move(Err)); }
1266 
1267  /// Check E. If it's in a success state then return the contained value. If
1268  /// it's in a failure state log the error(s) and exit.
1269  template <typename T> T operator()(Expected<T> &&E) const {
1270    checkError(E.takeError());
1271    return std::move(*E);
1272  }
1273 
1274  /// Check E. If it's in a success state then return the contained reference. If
1275  /// it's in a failure state log the error(s) and exit.
1276  template <typename T> T& operator()(Expected<T&> &&E) const {
1277    checkError(E.takeError());
1278    return *E;
1279  }
1280 
1281private:
1282  void checkError(Error Err) const {
1283    if (Err) {
1284      int ExitCode = GetExitCode(Err);
1285      logAllUnhandledErrors(std::move(Err), errs(), Banner);
1286      exit(ExitCode);
1287    }
1288  }
1289 
1290  std::string Banner;
1291  std::function<int(const Error &)> GetExitCode;
1292};
1293 
1294/// Conversion from Error to LLVMErrorRef for C error bindings.
1295inline LLVMErrorRef wrap(Error Err) {
1296  return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release());
1297}
1298 
1299/// Conversion from LLVMErrorRef to Error for C error bindings.
1300inline Error unwrap(LLVMErrorRef ErrRef) {
1301  return Error(std::unique_ptr<ErrorInfoBase>(
1302      reinterpret_cast<ErrorInfoBase *>(ErrRef)));
1303}
1304 
1305} // end namespace llvm
1306 
1307#endif // LLVM_SUPPORT_ERROR_H

←

/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h

1//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains some templates that are useful if you are working with the
10// STL at all.
11//
12// No library is required when using these functions.
13//
14//===----------------------------------------------------------------------===//
15 
16#ifndef LLVM_ADT_STLEXTRAS_H
17#define LLVM_ADT_STLEXTRAS_H
18 
19#include "llvm/ADT/Optional.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/ADT/iterator.h"
22#include "llvm/ADT/iterator_range.h"
23#include "llvm/Config/abi-breaking.h"
24#include "llvm/Support/ErrorHandling.h"
25#include <algorithm>
26#include <cassert>
27#include <cstddef>
28#include <cstdint>
29#include <cstdlib>
30#include <functional>
31#include <initializer_list>
32#include <iterator>
33#include <limits>
34#include <memory>
35#include <tuple>
36#include <type_traits>
37#include <utility>
38 
39#ifdef EXPENSIVE_CHECKS
40#include <random> // for std::mt19937
41#endif
42 
43namespace llvm {
44 
45// Only used by compiler if both template types are the same.  Useful when
46// using SFINAE to test for the existence of member functions.
47template <typename T, T> struct SameType;
48 
49namespace detail {
50 
51template <typename RangeT>
52using IterOfRange = decltype(std::begin(std::declval<RangeT &>()));
53 
54template <typename RangeT>
55using ValueOfRange = typename std::remove_reference<decltype(
56    *std::begin(std::declval<RangeT &>()))>::type;
57 
58} // end namespace detail
59 
60//===----------------------------------------------------------------------===//
61//     Extra additions to <type_traits>
62//===----------------------------------------------------------------------===//
63 
64template <typename T>
65struct negation : std::integral_constant<bool, !bool(T::value)> {};
66 
67template <typename...> struct conjunction : std::true_type {};
68template <typename B1> struct conjunction<B1> : B1 {};
69template <typename B1, typename... Bn>
70struct conjunction<B1, Bn...>
71    : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
72 
73template <typename T> struct make_const_ptr {
74  using type =
75      typename std::add_pointer<typename std::add_const<T>::type>::type;
76};
77 
78template <typename T> struct make_const_ref {
79  using type = typename std::add_lvalue_reference<
80      typename std::add_const<T>::type>::type;
81};
82 
83//===----------------------------------------------------------------------===//
84//     Extra additions to <functional>
85//===----------------------------------------------------------------------===//
86 
87template <class Ty> struct identity {
88  using argument_type = Ty;
89 
90  Ty &operator()(Ty &self) const {
91    return self;
92  }
93  const Ty &operator()(const Ty &self) const {
94    return self;
95  }
96};
97 
98template <class Ty> struct less_ptr {
99  bool operator()(const Ty* left, const Ty* right) const {
100    return *left < *right;
101  }
102};
103 
104template <class Ty> struct greater_ptr {
105  bool operator()(const Ty* left, const Ty* right) const {
106    return *right < *left;
107  }
108};
109 
110/// An efficient, type-erasing, non-owning reference to a callable. This is
111/// intended for use as the type of a function parameter that is not used
112/// after the function in question returns.
113///
114/// This class does not own the callable, so it is not in general safe to store
115/// a function_ref.
116template<typename Fn> class function_ref;
117 
118template<typename Ret, typename ...Params>
119class function_ref<Ret(Params...)> {
120  Ret (*callback)(intptr_t callable, Params ...params) = nullptr;
121  intptr_t callable;
122 
123  template<typename Callable>
124  static Ret callback_fn(intptr_t callable, Params ...params) {
125    return (*reinterpret_cast<Callable*>(callable))(
126        std::forward<Params>(params)...);
127  }
128 
129public:
130  function_ref() = default;
131  function_ref(std::nullptr_t) {}
132 
133  template <typename Callable>
134  function_ref(Callable &&callable,
135               typename std::enable_if<
136                   !std::is_same<typename std::remove_reference<Callable>::type,
137                                 function_ref>::value>::type * = nullptr)
138      : callback(callback_fn<typename std::remove_reference<Callable>::type>),
139        callable(reinterpret_cast<intptr_t>(&callable)) {}
140 
141  Ret operator()(Params ...params) const {
142    return callback(callable, std::forward<Params>(params)...);
143  }
144 
145  operator bool() const { return callback; }
146};
147 
148// deleter - Very very very simple method that is used to invoke operator
149// delete on something.  It is used like this:
150//
151//   for_each(V.begin(), B.end(), deleter<Interval>);
152template <class T>
153inline void deleter(T *Ptr) {
154  delete Ptr;
155}
156 
157//===----------------------------------------------------------------------===//
158//     Extra additions to <iterator>
159//===----------------------------------------------------------------------===//
160 
161namespace adl_detail {
162 
163using std::begin;
164 
165template <typename ContainerTy>
166auto adl_begin(ContainerTy &&container)
167    -> decltype(begin(std::forward<ContainerTy>(container))) {
168  return begin(std::forward<ContainerTy>(container));
169}
170 
171using std::end;
172 
173template <typename ContainerTy>
174auto adl_end(ContainerTy &&container)
175    -> decltype(end(std::forward<ContainerTy>(container))) {
176  return end(std::forward<ContainerTy>(container));
177}
178 
179using std::swap;
180 
181template <typename T>
182void adl_swap(T &&lhs, T &&rhs) noexcept(noexcept(swap(std::declval<T>(),
183                                                       std::declval<T>()))) {
184  swap(std::forward<T>(lhs), std::forward<T>(rhs));
185}
186 
187} // end namespace adl_detail
188 
189template <typename ContainerTy>
190auto adl_begin(ContainerTy &&container)
191    -> decltype(adl_detail::adl_begin(std::forward<ContainerTy>(container))) {
192  return adl_detail::adl_begin(std::forward<ContainerTy>(container));
193}
194 
195template <typename ContainerTy>
196auto adl_end(ContainerTy &&container)
197    -> decltype(adl_detail::adl_end(std::forward<ContainerTy>(container))) {
198  return adl_detail::adl_end(std::forward<ContainerTy>(container));
199}
200 
201template <typename T>
202void adl_swap(T &&lhs, T &&rhs) noexcept(
203    noexcept(adl_detail::adl_swap(std::declval<T>(), std::declval<T>()))) {
204  adl_detail::adl_swap(std::forward<T>(lhs), std::forward<T>(rhs));
205}
206 
207/// Test whether \p RangeOrContainer is empty. Similar to C++17 std::empty.
208template <typename T>
209constexpr bool empty(const T &RangeOrContainer) {
210  return adl_begin(RangeOrContainer) == adl_end(RangeOrContainer);
211}
212 
213// mapped_iterator - This is a simple iterator adapter that causes a function to
214// be applied whenever operator* is invoked on the iterator.
215 
216template <typename ItTy, typename FuncTy,
217          typename FuncReturnTy =
218            decltype(std::declval<FuncTy>()(*std::declval<ItTy>()))>
219class mapped_iterator
220    : public iterator_adaptor_base<
221             mapped_iterator<ItTy, FuncTy>, ItTy,
222             typename std::iterator_traits<ItTy>::iterator_category,
223             typename std::remove_reference<FuncReturnTy>::type> {
224public:
225  mapped_iterator(ItTy U, FuncTy F)
226    : mapped_iterator::iterator_adaptor_base(std::move(U)), F(std::move(F)) {}
227 
228  ItTy getCurrent() { return this->I; }
229 
230  FuncReturnTy operator*() { return F(*this->I); }
231 
232private:
233  FuncTy F;
234};
235 
236// map_iterator - Provide a convenient way to create mapped_iterators, just like
237// make_pair is useful for creating pairs...
238template <class ItTy, class FuncTy>
239inline mapped_iterator<ItTy, FuncTy> map_iterator(ItTy I, FuncTy F) {
240  return mapped_iterator<ItTy, FuncTy>(std::move(I), std::move(F));
241}
242 
243/// Helper to determine if type T has a member called rbegin().
244template <typename Ty> class has_rbegin_impl {
245  using yes = char[1];
246  using no = char[2];
247 
248  template <typename Inner>
249  static yes& test(Inner *I, decltype(I->rbegin()) * = nullptr);
250 
251  template <typename>
252  static no& test(...);
253 
254public:
255  static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes);
256};
257 
258/// Metafunction to determine if T& or T has a member called rbegin().
259template <typename Ty>
260struct has_rbegin : has_rbegin_impl<typename std::remove_reference<Ty>::type> {
261};
262 
263// Returns an iterator_range over the given container which iterates in reverse.
264// Note that the container must have rbegin()/rend() methods for this to work.
265template <typename ContainerTy>
266auto reverse(ContainerTy &&C,
267             typename std::enable_if<has_rbegin<ContainerTy>::value>::type * =
268                 nullptr) -> decltype(make_range(C.rbegin(), C.rend())) {
269  return make_range(C.rbegin(), C.rend());
270}
271 
272// Returns a std::reverse_iterator wrapped around the given iterator.
273template <typename IteratorTy>
274std::reverse_iterator<IteratorTy> make_reverse_iterator(IteratorTy It) {
275  return std::reverse_iterator<IteratorTy>(It);
276}
277 
278// Returns an iterator_range over the given container which iterates in reverse.
279// Note that the container must have begin()/end() methods which return
280// bidirectional iterators for this to work.
281template <typename ContainerTy>
282auto reverse(
283    ContainerTy &&C,
284    typename std::enable_if<!has_rbegin<ContainerTy>::value>::type * = nullptr)
285    -> decltype(make_range(llvm::make_reverse_iterator(std::end(C)),
286                           llvm::make_reverse_iterator(std::begin(C)))) {
287  return make_range(llvm::make_reverse_iterator(std::end(C)),
288                    llvm::make_reverse_iterator(std::begin(C)));
289}
290 
291/// An iterator adaptor that filters the elements of given inner iterators.
292///
293/// The predicate parameter should be a callable object that accepts the wrapped
294/// iterator's reference type and returns a bool. When incrementing or
295/// decrementing the iterator, it will call the predicate on each element and
296/// skip any where it returns false.
297///
298/// \code
299///   int A[] = { 1, 2, 3, 4 };
300///   auto R = make_filter_range(A, [](int N) { return N % 2 == 1; });
301///   // R contains { 1, 3 }.
302/// \endcode
303///
304/// Note: filter_iterator_base implements support for forward iteration.
305/// filter_iterator_impl exists to provide support for bidirectional iteration,
306/// conditional on whether the wrapped iterator supports it.
307template <typename WrappedIteratorT, typename PredicateT, typename IterTag>
308class filter_iterator_base
309    : public iterator_adaptor_base<
310          filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
311          WrappedIteratorT,
312          typename std::common_type<
313              IterTag, typename std::iterator_traits<
314                           WrappedIteratorT>::iterator_category>::type> {
315  using BaseT = iterator_adaptor_base<
316      filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
317      WrappedIteratorT,
318      typename std::common_type<
319          IterTag, typename std::iterator_traits<
320                       WrappedIteratorT>::iterator_category>::type>;
321 
322protected:
323  WrappedIteratorT End;
324  PredicateT Pred;
325 
326  void findNextValid() {
327    while (this->I != End && !Pred(*this->I))
328      BaseT::operator++();
329  }
330 
331  // Construct the iterator. The begin iterator needs to know where the end
332  // is, so that it can properly stop when it gets there. The end iterator only
333  // needs the predicate to support bidirectional iteration.
334  filter_iterator_base(WrappedIteratorT Begin, WrappedIteratorT End,
335                       PredicateT Pred)
336      : BaseT(Begin), End(End), Pred(Pred) {
337    findNextValid();
338  }
339 
340public:
341  using BaseT::operator++;
342 
343  filter_iterator_base &operator++() {
344    BaseT::operator++();
345    findNextValid();
346    return *this;
347  }
348};
349 
350/// Specialization of filter_iterator_base for forward iteration only.
351template <typename WrappedIteratorT, typename PredicateT,
352          typename IterTag = std::forward_iterator_tag>
353class filter_iterator_impl
354    : public filter_iterator_base<WrappedIteratorT, PredicateT, IterTag> {
355  using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>;
356 
357public:
358  filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
359                       PredicateT Pred)
360      : BaseT(Begin, End, Pred) {}
361};
362 
363/// Specialization of filter_iterator_base for bidirectional iteration.
364template <typename WrappedIteratorT, typename PredicateT>
365class filter_iterator_impl<WrappedIteratorT, PredicateT,
366                           std::bidirectional_iterator_tag>
367    : public filter_iterator_base<WrappedIteratorT, PredicateT,
368                                  std::bidirectional_iterator_tag> {
369  using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT,
370                                     std::bidirectional_iterator_tag>;
371  void findPrevValid() {
372    while (!this->Pred(*this->I))
373      BaseT::operator--();
374  }
375 
376public:
377  using BaseT::operator--;
378 
379  filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
380                       PredicateT Pred)
381      : BaseT(Begin, End, Pred) {}
382 
383  filter_iterator_impl &operator--() {
384    BaseT::operator--();
385    findPrevValid();
386    return *this;
387  }
388};
389 
390namespace detail {
391 
392template <bool is_bidirectional> struct fwd_or_bidi_tag_impl {
393  using type = std::forward_iterator_tag;
394};
395 
396template <> struct fwd_or_bidi_tag_impl<true> {
397  using type = std::bidirectional_iterator_tag;
398};
399 
400/// Helper which sets its type member to forward_iterator_tag if the category
401/// of \p IterT does not derive from bidirectional_iterator_tag, and to
402/// bidirectional_iterator_tag otherwise.
403template <typename IterT> struct fwd_or_bidi_tag {
404  using type = typename fwd_or_bidi_tag_impl<std::is_base_of<
405      std::bidirectional_iterator_tag,
406      typename std::iterator_traits<IterT>::iterator_category>::value>::type;
407};
408 
409} // namespace detail
410 
411/// Defines filter_iterator to a suitable specialization of
412/// filter_iterator_impl, based on the underlying iterator's category.
413template <typename WrappedIteratorT, typename PredicateT>
414using filter_iterator = filter_iterator_impl<
415    WrappedIteratorT, PredicateT,
416    typename detail::fwd_or_bidi_tag<WrappedIteratorT>::type>;
417 
418/// Convenience function that takes a range of elements and a predicate,
419/// and return a new filter_iterator range.
420///
421/// FIXME: Currently if RangeT && is a rvalue reference to a temporary, the
422/// lifetime of that temporary is not kept by the returned range object, and the
423/// temporary is going to be dropped on the floor after the make_iterator_range
424/// full expression that contains this function call.
425template <typename RangeT, typename PredicateT>
426iterator_range<filter_iterator<detail::IterOfRange<RangeT>, PredicateT>>
427make_filter_range(RangeT &&Range, PredicateT Pred) {
428  using FilterIteratorT =
429      filter_iterator<detail::IterOfRange<RangeT>, PredicateT>;
430  return make_range(
431      FilterIteratorT(std::begin(std::forward<RangeT>(Range)),
432                      std::end(std::forward<RangeT>(Range)), Pred),
433      FilterIteratorT(std::end(std::forward<RangeT>(Range)),
434                      std::end(std::forward<RangeT>(Range)), Pred));
435}
436 
437/// A pseudo-iterator adaptor that is designed to implement "early increment"
438/// style loops.
439///
440/// This is *not a normal iterator* and should almost never be used directly. It
441/// is intended primarily to be used with range based for loops and some range
442/// algorithms.
443///
444/// The iterator isn't quite an `OutputIterator` or an `InputIterator` but
445/// somewhere between them. The constraints of these iterators are:
446///
447/// - On construction or after being incremented, it is comparable and
448///   dereferencable. It is *not* incrementable.
449/// - After being dereferenced, it is neither comparable nor dereferencable, it
450///   is only incrementable.
451///
452/// This means you can only dereference the iterator once, and you can only
453/// increment it once between dereferences.
454template <typename WrappedIteratorT>
455class early_inc_iterator_impl
456    : public iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>,
457                                   WrappedIteratorT, std::input_iterator_tag> {
458  using BaseT =
459      iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>,
460                            WrappedIteratorT, std::input_iterator_tag>;
461 
462  using PointerT = typename std::iterator_traits<WrappedIteratorT>::pointer;
463 
464protected:
465#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
466  bool IsEarlyIncremented = false;
467#endif
468 
469public:
470  early_inc_iterator_impl(WrappedIteratorT I) : BaseT(I) {}
471 
472  using BaseT::operator*;
473  typename BaseT::reference operator*() {
474#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
475    assert(!IsEarlyIncremented && "Cannot dereference twice!")((!IsEarlyIncremented && "Cannot dereference twice!")
 ? static_cast<void> (0) : __assert_fail ("!IsEarlyIncremented && \"Cannot dereference twice!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 475, __PRETTY_FUNCTION__));
476    IsEarlyIncremented = true;
477#endif
478    return *(this->I)++;
479  }
480 
481  using BaseT::operator++;
482  early_inc_iterator_impl &operator++() {
483#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
484    assert(IsEarlyIncremented && "Cannot increment before dereferencing!")((IsEarlyIncremented && "Cannot increment before dereferencing!"
) ? static_cast<void> (0) : __assert_fail ("IsEarlyIncremented && \"Cannot increment before dereferencing!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 484, __PRETTY_FUNCTION__));
485    IsEarlyIncremented = false;
486#endif
487    return *this;
488  }
489 
490  using BaseT::operator==;
491  bool operator==(const early_inc_iterator_impl &RHS) const {
492#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
493    assert(!IsEarlyIncremented && "Cannot compare after dereferencing!")((!IsEarlyIncremented && "Cannot compare after dereferencing!"
) ? static_cast<void> (0) : __assert_fail ("!IsEarlyIncremented && \"Cannot compare after dereferencing!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 493, __PRETTY_FUNCTION__));
494#endif
495    return BaseT::operator==(RHS);
496  }
497};
498 
499/// Make a range that does early increment to allow mutation of the underlying
500/// range without disrupting iteration.
501///
502/// The underlying iterator will be incremented immediately after it is
503/// dereferenced, allowing deletion of the current node or insertion of nodes to
504/// not disrupt iteration provided they do not invalidate the *next* iterator --
505/// the current iterator can be invalidated.
506///
507/// This requires a very exact pattern of use that is only really suitable to
508/// range based for loops and other range algorithms that explicitly guarantee
509/// to dereference exactly once each element, and to increment exactly once each
510/// element.
511template <typename RangeT>
512iterator_range<early_inc_iterator_impl<detail::IterOfRange<RangeT>>>
513make_early_inc_range(RangeT &&Range) {
514  using EarlyIncIteratorT =
515      early_inc_iterator_impl<detail::IterOfRange<RangeT>>;
516  return make_range(EarlyIncIteratorT(std::begin(std::forward<RangeT>(Range))),
517                    EarlyIncIteratorT(std::end(std::forward<RangeT>(Range))));
518}
519 
520// forward declarations required by zip_shortest/zip_first/zip_longest
521template <typename R, typename UnaryPredicate>
522bool all_of(R &&range, UnaryPredicate P);
523template <typename R, typename UnaryPredicate>
524bool any_of(R &&range, UnaryPredicate P);
525 
526template <size_t... I> struct index_sequence;
527 
528template <class... Ts> struct index_sequence_for;
529 
530namespace detail {
531 
532using std::declval;
533 
534// We have to alias this since inlining the actual type at the usage site
535// in the parameter list of iterator_facade_base<> below ICEs MSVC 2017.
536template<typename... Iters> struct ZipTupleType {
537  using type = std::tuple<decltype(*declval<Iters>())...>;
538};
539 
540template <typename ZipType, typename... Iters>
541using zip_traits = iterator_facade_base<
542    ZipType, typename std::common_type<std::bidirectional_iterator_tag,
543                                       typename std::iterator_traits<
544                                           Iters>::iterator_category...>::type,
545    // ^ TODO: Implement random access methods.
546    typename ZipTupleType<Iters...>::type,
547    typename std::iterator_traits<typename std::tuple_element<
548        0, std::tuple<Iters...>>::type>::difference_type,
549    // ^ FIXME: This follows boost::make_zip_iterator's assumption that all
550    // inner iterators have the same difference_type. It would fail if, for
551    // instance, the second field's difference_type were non-numeric while the
552    // first is.
553    typename ZipTupleType<Iters...>::type *,
554    typename ZipTupleType<Iters...>::type>;
555 
556template <typename ZipType, typename... Iters>
557struct zip_common : public zip_traits<ZipType, Iters...> {
558  using Base = zip_traits<ZipType, Iters...>;
559  using value_type = typename Base::value_type;
560 
561  std::tuple<Iters...> iterators;
562 
563protected:
564  template <size_t... Ns> value_type deref(index_sequence<Ns...>) const {
565    return value_type(*std::get<Ns>(iterators)...);
566  }
567 
568  template <size_t... Ns>
569  decltype(iterators) tup_inc(index_sequence<Ns...>) const {
570    return std::tuple<Iters...>(std::next(std::get<Ns>(iterators))...);
571  }
572 
573  template <size_t... Ns>
574  decltype(iterators) tup_dec(index_sequence<Ns...>) const {
575    return std::tuple<Iters...>(std::prev(std::get<Ns>(iterators))...);
576  }
577 
578public:
579  zip_common(Iters &&... ts) : iterators(std::forward<Iters>(ts)...) {}
580 
581  value_type operator*() { return deref(index_sequence_for<Iters...>{}); }
582 
583  const value_type operator*() const {
584    return deref(index_sequence_for<Iters...>{});
585  }
586 
587  ZipType &operator++() {
588    iterators = tup_inc(index_sequence_for<Iters...>{});
589    return *reinterpret_cast<ZipType *>(this);
590  }
591 
592  ZipType &operator--() {
593    static_assert(Base::IsBidirectional,
594                  "All inner iterators must be at least bidirectional.");
595    iterators = tup_dec(index_sequence_for<Iters...>{});
596    return *reinterpret_cast<ZipType *>(this);
597  }
598};
599 
600template <typename... Iters>
601struct zip_first : public zip_common<zip_first<Iters...>, Iters...> {
602  using Base = zip_common<zip_first<Iters...>, Iters...>;
603 
604  bool operator==(const zip_first<Iters...> &other) const {
605    return std::get<0>(this->iterators) == std::get<0>(other.iterators);
606  }
607 
608  zip_first(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
609};
610 
611template <typename... Iters>
612class zip_shortest : public zip_common<zip_shortest<Iters...>, Iters...> {
613  template <size_t... Ns>
614  bool test(const zip_shortest<Iters...> &other, index_sequence<Ns...>) const {
615    return all_of(std::initializer_list<bool>{std::get<Ns>(this->iterators) !=
616                                              std::get<Ns>(other.iterators)...},
617                  identity<bool>{});
618  }
619 
620public:
621  using Base = zip_common<zip_shortest<Iters...>, Iters...>;
622 
623  zip_shortest(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
624 
625  bool operator==(const zip_shortest<Iters...> &other) const {
626    return !test(other, index_sequence_for<Iters...>{});
627  }
628};
629 
630template <template <typename...> class ItType, typename... Args> class zippy {
631public:
632  using iterator = ItType<decltype(std::begin(std::declval<Args>()))...>;
633  using iterator_category = typename iterator::iterator_category;
634  using value_type = typename iterator::value_type;
635  using difference_type = typename iterator::difference_type;
636  using pointer = typename iterator::pointer;
637  using reference = typename iterator::reference;
638 
639private:
640  std::tuple<Args...> ts;
641 
642  template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) const {
643    return iterator(std::begin(std::get<Ns>(ts))...);
644  }
645  template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) const {
646    return iterator(std::end(std::get<Ns>(ts))...);
647  }
648 
649public:
650  zippy(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {}
651 
652  iterator begin() const { return begin_impl(index_sequence_for<Args...>{}); }
653  iterator end() const { return end_impl(index_sequence_for<Args...>{}); }
654};
655 
656} // end namespace detail
657 
658/// zip iterator for two or more iteratable types.
659template <typename T, typename U, typename... Args>
660detail::zippy<detail::zip_shortest, T, U, Args...> zip(T &&t, U &&u,
661                                                       Args &&... args) {
662  return detail::zippy<detail::zip_shortest, T, U, Args...>(
663      std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
664}
665 
666/// zip iterator that, for the sake of efficiency, assumes the first iteratee to
667/// be the shortest.
668template <typename T, typename U, typename... Args>
669detail::zippy<detail::zip_first, T, U, Args...> zip_first(T &&t, U &&u,
670                                                          Args &&... args) {
671  return detail::zippy<detail::zip_first, T, U, Args...>(
672      std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
673}
674 
675namespace detail {
676template <typename Iter>
677static Iter next_or_end(const Iter &I, const Iter &End) {
678  if (I == End)
679    return End;
680  return std::next(I);
681}
682 
683template <typename Iter>
684static auto deref_or_none(const Iter &I, const Iter &End)
685    -> llvm::Optional<typename std::remove_const<
686        typename std::remove_reference<decltype(*I)>::type>::type> {
687  if (I == End)
688    return None;
689  return *I;
690}
691 
692template <typename Iter> struct ZipLongestItemType {
693  using type =
694      llvm::Optional<typename std::remove_const<typename std::remove_reference<
695          decltype(*std::declval<Iter>())>::type>::type>;
696};
697 
698template <typename... Iters> struct ZipLongestTupleType {
699  using type = std::tuple<typename ZipLongestItemType<Iters>::type...>;
700};
701 
702template <typename... Iters>
703class zip_longest_iterator
704    : public iterator_facade_base<
705          zip_longest_iterator<Iters...>,
706          typename std::common_type<
707              std::forward_iterator_tag,
708              typename std::iterator_traits<Iters>::iterator_category...>::type,
709          typename ZipLongestTupleType<Iters...>::type,
710          typename std::iterator_traits<typename std::tuple_element<
711              0, std::tuple<Iters...>>::type>::difference_type,
712          typename ZipLongestTupleType<Iters...>::type *,
713          typename ZipLongestTupleType<Iters...>::type> {
714public:
715  using value_type = typename ZipLongestTupleType<Iters...>::type;
716 
717private:
718  std::tuple<Iters...> iterators;
719  std::tuple<Iters...> end_iterators;
720 
721  template <size_t... Ns>
722  bool test(const zip_longest_iterator<Iters...> &other,
723            index_sequence<Ns...>) const {
724    return llvm::any_of(
725        std::initializer_list<bool>{std::get<Ns>(this->iterators) !=
726                                    std::get<Ns>(other.iterators)...},
727        identity<bool>{});
728  }
729 
730  template <size_t... Ns> value_type deref(index_sequence<Ns...>) const {
731    return value_type(
732        deref_or_none(std::get<Ns>(iterators), std::get<Ns>(end_iterators))...);
733  }
734 
735  template <size_t... Ns>
736  decltype(iterators) tup_inc(index_sequence<Ns...>) const {
737    return std::tuple<Iters...>(
738        next_or_end(std::get<Ns>(iterators), std::get<Ns>(end_iterators))...);
739  }
740 
741public:
742  zip_longest_iterator(std::pair<Iters &&, Iters &&>... ts)
743      : iterators(std::forward<Iters>(ts.first)...),
744        end_iterators(std::forward<Iters>(ts.second)...) {}
745 
746  value_type operator*() { return deref(index_sequence_for<Iters...>{}); }
747 
748  value_type operator*() const { return deref(index_sequence_for<Iters...>{}); }
749 
750  zip_longest_iterator<Iters...> &operator++() {
751    iterators = tup_inc(index_sequence_for<Iters...>{});
752    return *this;
753  }
754 
755  bool operator==(const zip_longest_iterator<Iters...> &other) const {
756    return !test(other, index_sequence_for<Iters...>{});
757  }
758};
759 
760template <typename... Args> class zip_longest_range {
761public:
762  using iterator =
763      zip_longest_iterator<decltype(adl_begin(std::declval<Args>()))...>;
764  using iterator_category = typename iterator::iterator_category;
765  using value_type = typename iterator::value_type;
766  using difference_type = typename iterator::difference_type;
767  using pointer = typename iterator::pointer;
768  using reference = typename iterator::reference;
769 
770private:
771  std::tuple<Args...> ts;
772 
773  template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) const {
774    return iterator(std::make_pair(adl_begin(std::get<Ns>(ts)),
775                                   adl_end(std::get<Ns>(ts)))...);
776  }
777 
778  template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) const {
779    return iterator(std::make_pair(adl_end(std::get<Ns>(ts)),
780                                   adl_end(std::get<Ns>(ts)))...);
781  }
782 
783public:
784  zip_longest_range(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {}
785 
786  iterator begin() const { return begin_impl(index_sequence_for<Args...>{}); }
787  iterator end() const { return end_impl(index_sequence_for<Args...>{}); }
788};
789} // namespace detail
790 
791/// Iterate over two or more iterators at the same time. Iteration continues
792/// until all iterators reach the end. The llvm::Optional only contains a value
793/// if the iterator has not reached the end.
794template <typename T, typename U, typename... Args>
795detail::zip_longest_range<T, U, Args...> zip_longest(T &&t, U &&u,
796                                                     Args &&... args) {
797  return detail::zip_longest_range<T, U, Args...>(
798      std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
799}
800 
801/// Iterator wrapper that concatenates sequences together.
802///
803/// This can concatenate different iterators, even with different types, into
804/// a single iterator provided the value types of all the concatenated
805/// iterators expose `reference` and `pointer` types that can be converted to
806/// `ValueT &` and `ValueT *` respectively. It doesn't support more
807/// interesting/customized pointer or reference types.
808///
809/// Currently this only supports forward or higher iterator categories as
810/// inputs and always exposes a forward iterator interface.
811template <typename ValueT, typename... IterTs>
812class concat_iterator
813    : public iterator_facade_base<concat_iterator<ValueT, IterTs...>,
814                                  std::forward_iterator_tag, ValueT> {
815  using BaseT = typename concat_iterator::iterator_facade_base;
816 
817  /// We store both the current and end iterators for each concatenated
818  /// sequence in a tuple of pairs.
819  ///
820  /// Note that something like iterator_range seems nice at first here, but the
821  /// range properties are of little benefit and end up getting in the way
822  /// because we need to do mutation on the current iterators.
823  std::tuple<IterTs...> Begins;
824  std::tuple<IterTs...> Ends;
825 
826  /// Attempts to increment a specific iterator.
827  ///
828  /// Returns true if it was able to increment the iterator. Returns false if
829  /// the iterator is already at the end iterator.
830  template <size_t Index> bool incrementHelper() {
831    auto &Begin = std::get<Index>(Begins);
832    auto &End = std::get<Index>(Ends);
833    if (Begin == End)
834      return false;
835 
836    ++Begin;
837    return true;
838  }
839 
840  /// Increments the first non-end iterator.
841  ///
842  /// It is an error to call this with all iterators at the end.
843  template <size_t... Ns> void increment(index_sequence<Ns...>) {
844    // Build a sequence of functions to increment each iterator if possible.
845    bool (concat_iterator::*IncrementHelperFns[])() = {
846        &concat_iterator::incrementHelper<Ns>...};
847 
848    // Loop over them, and stop as soon as we succeed at incrementing one.
849    for (auto &IncrementHelperFn : IncrementHelperFns)
850      if ((this->*IncrementHelperFn)())
851        return;
852 
853    llvm_unreachable("Attempted to increment an end concat iterator!")::llvm::llvm_unreachable_internal("Attempted to increment an end concat iterator!"
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 853);
854  }
855 
856  /// Returns null if the specified iterator is at the end. Otherwise,
857  /// dereferences the iterator and returns the address of the resulting
858  /// reference.
859  template <size_t Index> ValueT *getHelper() const {
860    auto &Begin = std::get<Index>(Begins);
861    auto &End = std::get<Index>(Ends);
862    if (Begin == End)
863      return nullptr;
864 
865    return &*Begin;
866  }
867 
868  /// Finds the first non-end iterator, dereferences, and returns the resulting
869  /// reference.
870  ///
871  /// It is an error to call this with all iterators at the end.
872  template <size_t... Ns> ValueT &get(index_sequence<Ns...>) const {
873    // Build a sequence of functions to get from iterator if possible.
874    ValueT *(concat_iterator::*GetHelperFns[])() const = {
875        &concat_iterator::getHelper<Ns>...};
876 
877    // Loop over them, and return the first result we find.
878    for (auto &GetHelperFn : GetHelperFns)
879      if (ValueT *P = (this->*GetHelperFn)())
880        return *P;
881 
882    llvm_unreachable("Attempted to get a pointer from an end concat iterator!")::llvm::llvm_unreachable_internal("Attempted to get a pointer from an end concat iterator!"
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 882);
883  }
884 
885public:
886  /// Constructs an iterator from a squence of ranges.
887  ///
888  /// We need the full range to know how to switch between each of the
889  /// iterators.
890  template <typename... RangeTs>
891  explicit concat_iterator(RangeTs &&... Ranges)
892      : Begins(std::begin(Ranges)...), Ends(std::end(Ranges)...) {}
893 
894  using BaseT::operator++;
895 
896  concat_iterator &operator++() {
897    increment(index_sequence_for<IterTs...>());
898    return *this;
899  }
900 
901  ValueT &operator*() const { return get(index_sequence_for<IterTs...>()); }
902 
903  bool operator==(const concat_iterator &RHS) const {
904    return Begins == RHS.Begins && Ends == RHS.Ends;
905  }
906};
907 
908namespace detail {
909 
910/// Helper to store a sequence of ranges being concatenated and access them.
911///
912/// This is designed to facilitate providing actual storage when temporaries
913/// are passed into the constructor such that we can use it as part of range
914/// based for loops.
915template <typename ValueT, typename... RangeTs> class concat_range {
916public:
917  using iterator =
918      concat_iterator<ValueT,
919                      decltype(std::begin(std::declval<RangeTs &>()))...>;
920 
921private:
922  std::tuple<RangeTs...> Ranges;
923 
924  template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) {
925    return iterator(std::get<Ns>(Ranges)...);
926  }
927  template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) {
928    return iterator(make_range(std::end(std::get<Ns>(Ranges)),
929                               std::end(std::get<Ns>(Ranges)))...);
930  }
931 
932public:
933  concat_range(RangeTs &&... Ranges)
934      : Ranges(std::forward<RangeTs>(Ranges)...) {}
935 
936  iterator begin() { return begin_impl(index_sequence_for<RangeTs...>{}); }
937  iterator end() { return end_impl(index_sequence_for<RangeTs...>{}); }
938};
939 
940} // end namespace detail
941 
942/// Concatenated range across two or more ranges.
943///
944/// The desired value type must be explicitly specified.
945template <typename ValueT, typename... RangeTs>
946detail::concat_range<ValueT, RangeTs...> concat(RangeTs &&... Ranges) {
947  static_assert(sizeof...(RangeTs) > 1,
948                "Need more than one range to concatenate!");
949  return detail::concat_range<ValueT, RangeTs...>(
950      std::forward<RangeTs>(Ranges)...);
951}
952 
953//===----------------------------------------------------------------------===//
954//     Extra additions to <utility>
955//===----------------------------------------------------------------------===//
956 
957/// Function object to check whether the first component of a std::pair
958/// compares less than the first component of another std::pair.
959struct less_first {
960  template <typename T> bool operator()(const T &lhs, const T &rhs) const {
961    return lhs.first < rhs.first;
962  }
963};
964 
965/// Function object to check whether the second component of a std::pair
966/// compares less than the second component of another std::pair.
967struct less_second {
968  template <typename T> bool operator()(const T &lhs, const T &rhs) const {
969    return lhs.second < rhs.second;
970  }
971};
972 
973/// \brief Function object to apply a binary function to the first component of
974/// a std::pair.
975template<typename FuncTy>
976struct on_first {
977  FuncTy func;
978 
979  template <typename T>
980  auto operator()(const T &lhs, const T &rhs) const
981      -> decltype(func(lhs.first, rhs.first)) {
982    return func(lhs.first, rhs.first);
983  }
984};
985 
986// A subset of N3658. More stuff can be added as-needed.
987 
988/// Represents a compile-time sequence of integers.
989template <class T, T... I> struct integer_sequence {
990  using value_type = T;
991 
992  static constexpr size_t size() { return sizeof...(I); }
993};
994 
995/// Alias for the common case of a sequence of size_ts.
996template <size_t... I>
997struct index_sequence : integer_sequence<std::size_t, I...> {};
998 
999template <std::size_t N, std::size_t... I>
1000struct build_index_impl : build_index_impl<N - 1, N - 1, I...> {};
1001template <std::size_t... I>
1002struct build_index_impl<0, I...> : index_sequence<I...> {};
1003 
1004/// Creates a compile-time integer sequence for a parameter pack.
1005template <class... Ts>
1006struct index_sequence_for : build_index_impl<sizeof...(Ts)> {};
1007 
1008/// Utility type to build an inheritance chain that makes it easy to rank
1009/// overload candidates.
1010template <int N> struct rank : rank<N - 1> {};
1011template <> struct rank<0> {};
1012 
1013/// traits class for checking whether type T is one of any of the given
1014/// types in the variadic list.
1015template <typename T, typename... Ts> struct is_one_of {
1016  static const bool value = false;
1017};
1018 
1019template <typename T, typename U, typename... Ts>
1020struct is_one_of<T, U, Ts...> {
1021  static const bool value =
1022      std::is_same<T, U>::value || is_one_of<T, Ts...>::value;
1023};
1024 
1025/// traits class for checking whether type T is a base class for all
1026///  the given types in the variadic list.
1027template <typename T, typename... Ts> struct are_base_of {
1028  static const bool value = true;
1029};
1030 
1031template <typename T, typename U, typename... Ts>
1032struct are_base_of<T, U, Ts...> {
1033  static const bool value =
1034      std::is_base_of<T, U>::value && are_base_of<T, Ts...>::value;
1035};
1036 
1037//===----------------------------------------------------------------------===//
1038//     Extra additions for arrays
1039//===----------------------------------------------------------------------===//
1040 
1041/// Find the length of an array.
1042template <class T, std::size_t N>
1043constexpr inline size_t array_lengthof(T (&)[N]) {
1044  return N;
1045}
1046 
1047/// Adapt std::less<T> for array_pod_sort.
1048template<typename T>
1049inline int array_pod_sort_comparator(const void *P1, const void *P2) {
1050  if (std::less<T>()(*reinterpret_cast<const T*>(P1),
1051                     *reinterpret_cast<const T*>(P2)))
1052    return -1;
1053  if (std::less<T>()(*reinterpret_cast<const T*>(P2),
1054                     *reinterpret_cast<const T*>(P1)))
1055    return 1;
1056  return 0;
1057}
1058 
1059/// get_array_pod_sort_comparator - This is an internal helper function used to
1060/// get type deduction of T right.
1061template<typename T>
1062inline int (*get_array_pod_sort_comparator(const T &))
1063             (const void*, const void*) {
1064  return array_pod_sort_comparator<T>;
1065}
1066 
1067/// array_pod_sort - This sorts an array with the specified start and end
1068/// extent.  This is just like std::sort, except that it calls qsort instead of
1069/// using an inlined template.  qsort is slightly slower than std::sort, but
1070/// most sorts are not performance critical in LLVM and std::sort has to be
1071/// template instantiated for each type, leading to significant measured code
1072/// bloat.  This function should generally be used instead of std::sort where
1073/// possible.
1074///
1075/// This function assumes that you have simple POD-like types that can be
1076/// compared with std::less and can be moved with memcpy.  If this isn't true,
1077/// you should use std::sort.
1078///
1079/// NOTE: If qsort_r were portable, we could allow a custom comparator and
1080/// default to std::less.
1081template<class IteratorTy>
1082inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
1083  // Don't inefficiently call qsort with one element or trigger undefined
1084  // behavior with an empty sequence.
1085  auto NElts = End - Start;
1086  if (NElts <= 1) return;
1087#ifdef EXPENSIVE_CHECKS
1088  std::mt19937 Generator(std::random_device{}());
1089  std::shuffle(Start, End, Generator);
1090#endif
1091  qsort(&*Start, NElts, sizeof(*Start), get_array_pod_sort_comparator(*Start));
1092}
1093 
1094template <class IteratorTy>
1095inline void array_pod_sort(
1096    IteratorTy Start, IteratorTy End,
1097    int (*Compare)(
1098        const typename std::iterator_traits<IteratorTy>::value_type *,
1099        const typename std::iterator_traits<IteratorTy>::value_type *)) {
1100  // Don't inefficiently call qsort with one element or trigger undefined
1101  // behavior with an empty sequence.
1102  auto NElts = End - Start;
1103  if (NElts <= 1) return;
1104#ifdef EXPENSIVE_CHECKS
1105  std::mt19937 Generator(std::random_device{}());
1106  std::shuffle(Start, End, Generator);
1107#endif
1108  qsort(&*Start, NElts, sizeof(*Start),
1109        reinterpret_cast<int (*)(const void *, const void *)>(Compare));
1110}
1111 
1112// Provide wrappers to std::sort which shuffle the elements before sorting
1113// to help uncover non-deterministic behavior (PR35135).
1114template <typename IteratorTy>
1115inline void sort(IteratorTy Start, IteratorTy End) {
1116#ifdef EXPENSIVE_CHECKS
1117  std::mt19937 Generator(std::random_device{}());
1118  std::shuffle(Start, End, Generator);
1119#endif
1120  std::sort(Start, End);
1121}
1122 
1123template <typename Container> inline void sort(Container &&C) {
1124  llvm::sort(adl_begin(C), adl_end(C));
1125}
1126 
1127template <typename IteratorTy, typename Compare>
1128inline void sort(IteratorTy Start, IteratorTy End, Compare Comp) {
1129#ifdef EXPENSIVE_CHECKS
1130  std::mt19937 Generator(std::random_device{}());
1131  std::shuffle(Start, End, Generator);
1132#endif
1133  std::sort(Start, End, Comp);
1134}
1135 
1136template <typename Container, typename Compare>
1137inline void sort(Container &&C, Compare Comp) {
1138  llvm::sort(adl_begin(C), adl_end(C), Comp);
1139}
1140 
1141//===----------------------------------------------------------------------===//
1142//     Extra additions to <algorithm>
1143//===----------------------------------------------------------------------===//
1144 
1145/// For a container of pointers, deletes the pointers and then clears the
1146/// container.
1147template<typename Container>
1148void DeleteContainerPointers(Container &C) {
1149  for (auto V : C)
1150    delete V;
1151  C.clear();
1152}
1153 
1154/// In a container of pairs (usually a map) whose second element is a pointer,
1155/// deletes the second elements and then clears the container.
1156template<typename Container>
1157void DeleteContainerSeconds(Container &C) {
1158  for (auto &V : C)
1159    delete V.second;
1160  C.clear();
1161}
1162 
1163/// Get the size of a range. This is a wrapper function around std::distance
1164/// which is only enabled when the operation is O(1).
1165template <typename R>
1166auto size(R &&Range, typename std::enable_if<
1167                         std::is_same<typename std::iterator_traits<decltype(
1168                                          Range.begin())>::iterator_category,
1169                                      std::random_access_iterator_tag>::value,
1170                         void>::type * = nullptr)
1171    -> decltype(std::distance(Range.begin(), Range.end())) {
1172  return std::distance(Range.begin(), Range.end());
1173}
1174 
1175/// Provide wrappers to std::for_each which take ranges instead of having to
1176/// pass begin/end explicitly.
1177template <typename R, typename UnaryPredicate>
1178UnaryPredicate for_each(R &&Range, UnaryPredicate P) {
1179  return std::for_each(adl_begin(Range), adl_end(Range), P);
1180}
1181 
1182/// Provide wrappers to std::all_of which take ranges instead of having to pass
1183/// begin/end explicitly.
1184template <typename R, typename UnaryPredicate>
1185bool all_of(R &&Range, UnaryPredicate P) {
1186  return std::all_of(adl_begin(Range), adl_end(Range), P);
1187}
1188 
1189/// Provide wrappers to std::any_of which take ranges instead of having to pass
1190/// begin/end explicitly.
1191template <typename R, typename UnaryPredicate>
1192bool any_of(R &&Range, UnaryPredicate P) {
1193  return std::any_of(adl_begin(Range), adl_end(Range), P);
1194}
1195 
1196/// Provide wrappers to std::none_of which take ranges instead of having to pass
1197/// begin/end explicitly.
1198template <typename R, typename UnaryPredicate>
1199bool none_of(R &&Range, UnaryPredicate P) {
1200  return std::none_of(adl_begin(Range), adl_end(Range), P);
1201}
1202 
1203/// Provide wrappers to std::find which take ranges instead of having to pass
1204/// begin/end explicitly.
1205template <typename R, typename T>
1206auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range)) {
1207  return std::find(adl_begin(Range), adl_end(Range), Val);
1208}
1209 
1210/// Provide wrappers to std::find_if which take ranges instead of having to pass
1211/// begin/end explicitly.
1212template <typename R, typename UnaryPredicate>
1213auto find_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1214  return std::find_if(adl_begin(Range), adl_end(Range), P);
1215}
1216 
1217template <typename R, typename UnaryPredicate>
1218auto find_if_not(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1219  return std::find_if_not(adl_begin(Range), adl_end(Range), P);
1220}
1221 
1222/// Provide wrappers to std::remove_if which take ranges instead of having to
1223/// pass begin/end explicitly.
1224template <typename R, typename UnaryPredicate>
1225auto remove_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1226  return std::remove_if(adl_begin(Range), adl_end(Range), P);
1227}
1228 
1229/// Provide wrappers to std::copy_if which take ranges instead of having to
1230/// pass begin/end explicitly.
1231template <typename R, typename OutputIt, typename UnaryPredicate>
1232OutputIt copy_if(R &&Range, OutputIt Out, UnaryPredicate P) {
1233  return std::copy_if(adl_begin(Range), adl_end(Range), Out, P);
1234}
1235 
1236template <typename R, typename OutputIt>
1237OutputIt copy(R &&Range, OutputIt Out) {
1238  return std::copy(adl_begin(Range), adl_end(Range), Out);
1239}
1240 
1241/// Wrapper function around std::find to detect if an element exists
1242/// in a container.
1243template <typename R, typename E>
1244bool is_contained(R &&Range, const E &Element) {
1245  return std::find(adl_begin(Range), adl_end(Range), Element) != adl_end(Range);
1246}
1247 
1248/// Wrapper function around std::count to count the number of times an element
1249/// \p Element occurs in the given range \p Range.
1250template <typename R, typename E>
1251auto count(R &&Range, const E &Element) ->
1252    typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
1253  return std::count(adl_begin(Range), adl_end(Range), Element);
1254}
1255 
1256/// Wrapper function around std::count_if to count the number of times an
1257/// element satisfying a given predicate occurs in a range.
1258template <typename R, typename UnaryPredicate>
1259auto count_if(R &&Range, UnaryPredicate P) ->
1260    typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
1261  return std::count_if(adl_begin(Range), adl_end(Range), P);
1262}
1263 
1264/// Wrapper function around std::transform to apply a function to a range and
1265/// store the result elsewhere.
1266template <typename R, typename OutputIt, typename UnaryPredicate>
1267OutputIt transform(R &&Range, OutputIt d_first, UnaryPredicate P) {
1268  return std::transform(adl_begin(Range), adl_end(Range), d_first, P);
1269}
1270 
1271/// Provide wrappers to std::partition which take ranges instead of having to
1272/// pass begin/end explicitly.
1273template <typename R, typename UnaryPredicate>
1274auto partition(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1275  return std::partition(adl_begin(Range), adl_end(Range), P);
1276}
1277 
1278/// Provide wrappers to std::lower_bound which take ranges instead of having to
1279/// pass begin/end explicitly.
1280template <typename R, typename T>
1281auto lower_bound(R &&Range, T &&Value) -> decltype(adl_begin(Range)) {
1282  return std::lower_bound(adl_begin(Range), adl_end(Range),
1283                          std::forward<T>(Value));
1284}
1285 
1286template <typename R, typename T, typename Compare>
1287auto lower_bound(R &&Range, T &&Value, Compare C)
1288    -> decltype(adl_begin(Range)) {
1289  return std::lower_bound(adl_begin(Range), adl_end(Range),
1290                          std::forward<T>(Value), C);
1291}
1292 
1293/// Provide wrappers to std::upper_bound which take ranges instead of having to
1294/// pass begin/end explicitly.
1295template <typename R, typename T>
1296auto upper_bound(R &&Range, T &&Value) -> decltype(adl_begin(Range)) {
1297  return std::upper_bound(adl_begin(Range), adl_end(Range),
1298                          std::forward<T>(Value));
1299}
1300 
1301template <typename R, typename T, typename Compare>
1302auto upper_bound(R &&Range, T &&Value, Compare C)
1303    -> decltype(adl_begin(Range)) {
1304  return std::upper_bound(adl_begin(Range), adl_end(Range),
1305                          std::forward<T>(Value), C);
1306}
1307 
1308template <typename R>
1309void stable_sort(R &&Range) {
1310  std::stable_sort(adl_begin(Range), adl_end(Range));
1311}
1312 
1313template <typename R, typename Compare>
1314void stable_sort(R &&Range, Compare C) {
1315  std::stable_sort(adl_begin(Range), adl_end(Range), C);
1316}
1317 
1318/// Binary search for the first index where a predicate is true.
1319/// Returns the first I in [Lo, Hi) where C(I) is true, or Hi if it never is.
1320/// Requires that C is always false below some limit, and always true above it.
1321///
1322/// Example:
1323///   size_t DawnModernEra = bsearch(1776, 2050, [](size_t Year){
1324///     return Presidents.for(Year).twitterHandle() != None;
1325///   });
1326///
1327/// Note the return value differs from std::binary_search!
1328template <typename Predicate>
1329size_t bsearch(size_t Lo, size_t Hi, Predicate P) {
1330  while (Lo != Hi) {
1331    assert(Hi > Lo)((Hi > Lo) ? static_cast<void> (0) : __assert_fail (
"Hi > Lo", "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 1331, __PRETTY_FUNCTION__));
1332    size_t Mid = Lo + (Hi - Lo) / 2;
1333    if (P(Mid))
1334      Hi = Mid;
1335    else
1336      Lo = Mid + 1;
1337  }
1338  return Hi;
1339}
1340 
1341/// Binary search for the first iterator where a predicate is true.
1342/// Returns the first I in [Lo, Hi) where C(*I) is true, or Hi if it never is.
1343/// Requires that C is always false below some limit, and always true above it.
1344template <typename It, typename Predicate,
1345          typename Val = decltype(*std::declval<It>())>
1346It bsearch(It Lo, It Hi, Predicate P) {
1347  return std::lower_bound(Lo, Hi, 0u,
1348                          [&](const Val &V, unsigned) { return !P(V); });
1349}
1350 
1351/// Binary search for the first iterator in a range where a predicate is true.
1352/// Requires that C is always false below some limit, and always true above it.
1353template <typename R, typename Predicate>
1354auto bsearch(R &&Range, Predicate P) -> decltype(adl_begin(Range)) {
1355  return bsearch(adl_begin(Range), adl_end(Range), P);
1356}
1357 
1358/// Wrapper function around std::equal to detect if all elements
1359/// in a container are same.
1360template <typename R>
1361bool is_splat(R &&Range) {
1362  size_t range_size = size(Range);
1363  return range_size != 0 && (range_size == 1 ||
1364         std::equal(adl_begin(Range) + 1, adl_end(Range), adl_begin(Range)));
1365}
1366 
1367/// Given a range of type R, iterate the entire range and return a
1368/// SmallVector with elements of the vector.  This is useful, for example,
1369/// when you want to iterate a range and then sort the results.
1370template <unsigned Size, typename R>
1371SmallVector<typename std::remove_const<detail::ValueOfRange<R>>::type, Size>
1372to_vector(R &&Range) {
1373  return {adl_begin(Range), adl_end(Range)};
1374}
1375 
1376/// Provide a container algorithm similar to C++ Library Fundamentals v2's
1377/// `erase_if` which is equivalent to:
1378///
1379///   C.erase(remove_if(C, pred), C.end());
1380///
1381/// This version works for any container with an erase method call accepting
1382/// two iterators.
1383template <typename Container, typename UnaryPredicate>
1384void erase_if(Container &C, UnaryPredicate P) {
1385  C.erase(remove_if(C, P), C.end());
1386}
1387 
1388//===----------------------------------------------------------------------===//
1389//     Extra additions to <memory>
1390//===----------------------------------------------------------------------===//
1391 
1392// Implement make_unique according to N3656.
1393 
1394/// Constructs a `new T()` with the given args and returns a
1395///        `unique_ptr<T>` which owns the object.
1396///
1397/// Example:
1398///
1399///     auto p = make_unique<int>();
1400///     auto p = make_unique<std::tuple<int, int>>(0, 1);
1401template <class T, class... Args>
1402typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
1403make_unique(Args &&... args) {
1404  return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
9
←
Memory is allocated→
1405}
1406 
1407/// Constructs a `new T[n]` with the given args and returns a
1408///        `unique_ptr<T[]>` which owns the object.
1409///
1410/// \param n size of the new array.
1411///
1412/// Example:
1413///
1414///     auto p = make_unique<int[]>(2); // value-initializes the array with 0's.
1415template <class T>
1416typename std::enable_if<std::is_array<T>::value && std::extent<T>::value == 0,
1417                        std::unique_ptr<T>>::type
1418make_unique(size_t n) {
1419  return std::unique_ptr<T>(new typename std::remove_extent<T>::type[n]());
1420}
1421 
1422/// This function isn't used and is only here to provide better compile errors.
1423template <class T, class... Args>
1424typename std::enable_if<std::extent<T>::value != 0>::type
1425make_unique(Args &&...) = delete;
1426 
1427struct FreeDeleter {
1428  void operator()(void* v) {
1429    ::free(v);
1430  }
1431};
1432 
1433template<typename First, typename Second>
1434struct pair_hash {
1435  size_t operator()(const std::pair<First, Second> &P) const {
1436    return std::hash<First>()(P.first) * 31 + std::hash<Second>()(P.second);
1437  }
1438};
1439 
1440/// A functor like C++14's std::less<void> in its absence.
1441struct less {
1442  template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1443    return std::forward<A>(a) < std::forward<B>(b);
1444  }
1445};
1446 
1447/// A functor like C++14's std::equal<void> in its absence.
1448struct equal {
1449  template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1450    return std::forward<A>(a) == std::forward<B>(b);
1451  }
1452};
1453 
1454/// Binary functor that adapts to any other binary functor after dereferencing
1455/// operands.
1456template <typename T> struct deref {
1457  T func;
1458 
1459  // Could be further improved to cope with non-derivable functors and
1460  // non-binary functors (should be a variadic template member function
1461  // operator()).
1462  template <typename A, typename B>
1463  auto operator()(A &lhs, B &rhs) const -> decltype(func(*lhs, *rhs)) {
1464    assert(lhs)((lhs) ? static_cast<void> (0) : __assert_fail ("lhs", "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 1464, __PRETTY_FUNCTION__));
1465    assert(rhs)((rhs) ? static_cast<void> (0) : __assert_fail ("rhs", "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 1465, __PRETTY_FUNCTION__));
1466    return func(*lhs, *rhs);
1467  }
1468};
1469 
1470namespace detail {
1471 
1472template <typename R> class enumerator_iter;
1473 
1474template <typename R> struct result_pair {
1475  friend class enumerator_iter<R>;
1476 
1477  result_pair() = default;
1478  result_pair(std::size_t Index, IterOfRange<R> Iter)
1479      : Index(Index), Iter(Iter) {}
1480 
1481  result_pair<R> &operator=(const result_pair<R> &Other) {
1482    Index = Other.Index;
1483    Iter = Other.Iter;
1484    return *this;
1485  }
1486 
1487  std::size_t index() const { return Index; }
1488  const ValueOfRange<R> &value() const { return *Iter; }
1489  ValueOfRange<R> &value() { return *Iter; }
1490 
1491private:
1492  std::size_t Index = std::numeric_limits<std::size_t>::max();
1493  IterOfRange<R> Iter;
1494};
1495 
1496template <typename R>
1497class enumerator_iter
1498    : public iterator_facade_base<
1499          enumerator_iter<R>, std::forward_iterator_tag, result_pair<R>,
1500          typename std::iterator_traits<IterOfRange<R>>::difference_type,
1501          typename std::iterator_traits<IterOfRange<R>>::pointer,
1502          typename std::iterator_traits<IterOfRange<R>>::reference> {
1503  using result_type = result_pair<R>;
1504 
1505public:
1506  explicit enumerator_iter(IterOfRange<R> EndIter)
1507      : Result(std::numeric_limits<size_t>::max(), EndIter) {}
1508 
1509  enumerator_iter(std::size_t Index, IterOfRange<R> Iter)
1510      : Result(Index, Iter) {}
1511 
1512  result_type &operator*() { return Result; }
1513  const result_type &operator*() const { return Result; }
1514 
1515  enumerator_iter<R> &operator++() {
1516    assert(Result.Index != std::numeric_limits<size_t>::max())((Result.Index != std::numeric_limits<size_t>::max()) ?
 static_cast<void> (0) : __assert_fail ("Result.Index != std::numeric_limits<size_t>::max()"
, "/build/llvm-toolchain-snapshot-9~svn362543/include/llvm/ADT/STLExtras.h"
, 1516, __PRETTY_FUNCTION__));
1517    ++Result.Iter;
1518    ++Result.Index;
1519    return *this;
1520  }
1521 
1522  bool operator==(const enumerator_iter<R> &RHS) const {
1523    // Don't compare indices here, only iterators.  It's possible for an end
1524    // iterator to have different indices depending on whether it was created
1525    // by calling std::end() versus incrementing a valid iterator.
1526    return Result.Iter == RHS.Result.Iter;
1527  }
1528 
1529  enumerator_iter<R> &operator=(const enumerator_iter<R> &Other) {
1530    Result = Other.Result;
1531    return *this;
1532  }
1533 
1534private:
1535  result_type Result;
1536};
1537 
1538template <typename R> class enumerator {
1539public:
1540  explicit enumerator(R &&Range) : TheRange(std::forward<R>(Range)) {}
1541 
1542  enumerator_iter<R> begin() {
1543    return enumerator_iter<R>(0, std::begin(TheRange));
1544  }
1545 
1546  enumerator_iter<R> end() {
1547    return enumerator_iter<R>(std::end(TheRange));
1548  }
1549 
1550private:
1551  R TheRange;
1552};
1553 
1554} // end namespace detail
1555 
1556/// Given an input range, returns a new range whose values are are pair (A,B)
1557/// such that A is the 0-based index of the item in the sequence, and B is
1558/// the value from the original sequence.  Example:
1559///
1560/// std::vector<char> Items = {'A', 'B', 'C', 'D'};
1561/// for (auto X : enumerate(Items)) {
1562///   printf("Item %d - %c\n", X.index(), X.value());
1563/// }
1564///
1565/// Output:
1566///   Item 0 - A
1567///   Item 1 - B
1568///   Item 2 - C
1569///   Item 3 - D
1570///
1571template <typename R> detail::enumerator<R> enumerate(R &&TheRange) {
1572  return detail::enumerator<R>(std::forward<R>(TheRange));
1573}
1574 
1575namespace detail {
1576 
1577template <typename F, typename Tuple, std::size_t... I>
1578auto apply_tuple_impl(F &&f, Tuple &&t, index_sequence<I...>)
1579    -> decltype(std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...)) {
1580  return std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...);
1581}
1582 
1583} // end namespace detail
1584 
1585/// Given an input tuple (a1, a2, ..., an), pass the arguments of the
1586/// tuple variadically to f as if by calling f(a1, a2, ..., an) and
1587/// return the result.
1588template <typename F, typename Tuple>
1589auto apply_tuple(F &&f, Tuple &&t) -> decltype(detail::apply_tuple_impl(
1590    std::forward<F>(f), std::forward<Tuple>(t),
1591    build_index_impl<
1592        std::tuple_size<typename std::decay<Tuple>::type>::value>{})) {
1593  using Indices = build_index_impl<
1594      std::tuple_size<typename std::decay<Tuple>::type>::value>;
1595 
1596  return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t),
1597                                  Indices{});
1598}
1599 
1600/// Return true if the sequence [Begin, End) has exactly N items. Runs in O(N)
1601/// time. Not meant for use with random-access iterators.
1602template <typename IterTy>
1603bool hasNItems(
1604    IterTy &&Begin, IterTy &&End, unsigned N,
1605    typename std::enable_if<
1606        !std::is_same<
1607            typename std::iterator_traits<typename std::remove_reference<
1608                decltype(Begin)>::type>::iterator_category,
1609            std::random_access_iterator_tag>::value,
1610        void>::type * = nullptr) {
1611  for (; N; --N, ++Begin)
1612    if (Begin == End)
1613      return false; // Too few.
1614  return Begin == End;
1615}
1616 
1617/// Return true if the sequence [Begin, End) has N or more items. Runs in O(N)
1618/// time. Not meant for use with random-access iterators.
1619template <typename IterTy>
1620bool hasNItemsOrMore(
1621    IterTy &&Begin, IterTy &&End, unsigned N,
1622    typename std::enable_if<
1623        !std::is_same<
1624            typename std::iterator_traits<typename std::remove_reference<
1625                decltype(Begin)>::type>::iterator_category,
1626            std::random_access_iterator_tag>::value,
1627        void>::type * = nullptr) {
1628  for (; N; --N, ++Begin)
1629    if (Begin == End)
1630      return false; // Too few.
1631  return true;
1632}
1633 
1634/// Returns a raw pointer that represents the same address as the argument.
1635///
1636/// The late bound return should be removed once we move to C++14 to better
1637/// align with the C++20 declaration. Also, this implementation can be removed
1638/// once we move to C++20 where it's defined as std::to_addres()
1639///
1640/// The std::pointer_traits<>::to_address(p) variations of these overloads has
1641/// not been implemented.
1642template <class Ptr> auto to_address(const Ptr &P) -> decltype(P.operator->()) {
1643  return P.operator->();
1644}
1645template <class T> constexpr T *to_address(T *P) { return P; }
1646 
1647} // end namespace llvm
1648 
1649#endif // LLVM_ADT_STLEXTRAS_H