LLVM 18.0.0git
MachOObject.cpp
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1//===- MachOObject.cpp - Mach-O object file model ---------------*- 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#include "MachOObject.h"
11#include <unordered_set>
12
13using namespace llvm;
14using namespace llvm::objcopy::macho;
15
17 : Segname(SegName), Sectname(SectName),
18 CanonicalName((Twine(SegName) + Twine(',') + SectName).str()) {}
19
21 : Segname(SegName), Sectname(SectName),
22 CanonicalName((Twine(SegName) + Twine(',') + SectName).str()),
24
26 assert(Index < Symbols.size() && "invalid symbol index");
27 return Symbols[Index].get();
28}
29
31 return const_cast<SymbolEntry *>(
32 static_cast<const SymbolTable *>(this)->getSymbolByIndex(Index));
33}
34
36 function_ref<bool(const std::unique_ptr<SymbolEntry> &)> ToRemove) {
38}
39
41 static constexpr char TextSegmentName[] = "__TEXT";
42 // Update indices of special load commands
43 for (size_t Index = 0, Size = LoadCommands.size(); Index < Size; ++Index) {
45 switch (LC.MachOLoadCommand.load_command_data.cmd) {
46 case MachO::LC_CODE_SIGNATURE:
48 break;
49 case MachO::LC_SEGMENT:
50 if (StringRef(LC.MachOLoadCommand.segment_command_data.segname) ==
51 TextSegmentName)
53 break;
54 case MachO::LC_SEGMENT_64:
55 if (StringRef(LC.MachOLoadCommand.segment_command_64_data.segname) ==
56 TextSegmentName)
58 break;
59 case MachO::LC_SYMTAB:
61 break;
62 case MachO::LC_DYSYMTAB:
64 break;
65 case MachO::LC_DYLD_INFO:
66 case MachO::LC_DYLD_INFO_ONLY:
68 break;
69 case MachO::LC_DATA_IN_CODE:
71 break;
72 case MachO::LC_LINKER_OPTIMIZATION_HINT:
74 break;
75 case MachO::LC_FUNCTION_STARTS:
77 break;
78 case MachO::LC_DYLIB_CODE_SIGN_DRS:
80 break;
81 case MachO::LC_DYLD_CHAINED_FIXUPS:
83 break;
84 case MachO::LC_DYLD_EXPORTS_TRIE:
86 break;
87 }
88 }
89}
90
92 function_ref<bool(const LoadCommand &)> ToRemove) {
93 auto It = std::stable_partition(
94 LoadCommands.begin(), LoadCommands.end(),
95 [&](const LoadCommand &LC) { return !ToRemove(LC); });
96 LoadCommands.erase(It, LoadCommands.end());
97
99 return Error::success();
100}
101
103 function_ref<bool(const std::unique_ptr<Section> &)> ToRemove) {
104 DenseMap<uint32_t, const Section *> OldIndexToSection;
105 uint32_t NextSectionIndex = 1;
106 for (LoadCommand &LC : LoadCommands) {
107 auto It = std::stable_partition(
108 std::begin(LC.Sections), std::end(LC.Sections),
109 [&](const std::unique_ptr<Section> &Sec) { return !ToRemove(Sec); });
110 for (auto I = LC.Sections.begin(), End = It; I != End; ++I) {
111 OldIndexToSection[(*I)->Index] = I->get();
112 (*I)->Index = NextSectionIndex++;
113 }
114 LC.Sections.erase(It, LC.Sections.end());
115 }
116
117 auto IsDead = [&](const std::unique_ptr<SymbolEntry> &S) -> bool {
118 std::optional<uint32_t> Section = S->section();
119 return (Section && !OldIndexToSection.count(*Section));
120 };
121
123 for (const std::unique_ptr<SymbolEntry> &Sym : SymTable.Symbols)
124 if (IsDead(Sym))
125 DeadSymbols.insert(Sym.get());
126
127 for (const LoadCommand &LC : LoadCommands)
128 for (const std::unique_ptr<Section> &Sec : LC.Sections)
129 for (const RelocationInfo &R : Sec->Relocations)
130 if (R.Symbol && *R.Symbol && DeadSymbols.count(*R.Symbol))
131 return createStringError(std::errc::invalid_argument,
132 "symbol '%s' defined in section with index "
133 "'%u' cannot be removed because it is "
134 "referenced by a relocation in section '%s'",
135 (*R.Symbol)->Name.c_str(),
136 *((*R.Symbol)->section()),
137 Sec->CanonicalName.c_str());
139 for (std::unique_ptr<SymbolEntry> &S : SymTable.Symbols)
140 if (S->section())
141 S->n_sect = OldIndexToSection[S->n_sect]->Index;
142 return Error::success();
143}
144
146 uint64_t HeaderSize =
148 uint64_t Addr = HeaderSize + Header.SizeOfCmds;
149 for (const LoadCommand &LC : LoadCommands) {
150 const MachO::macho_load_command &MLC = LC.MachOLoadCommand;
151 switch (MLC.load_command_data.cmd) {
152 case MachO::LC_SEGMENT:
153 Addr = std::max(Addr,
154 static_cast<uint64_t>(MLC.segment_command_data.vmaddr) +
155 MLC.segment_command_data.vmsize);
156 break;
157 case MachO::LC_SEGMENT_64:
158 Addr = std::max(Addr, MLC.segment_command_64_data.vmaddr +
159 MLC.segment_command_64_data.vmsize);
160 break;
161 default:
162 continue;
163 }
164 }
165 return Addr;
166}
167
168template <typename SegmentType>
169static void
171 StringRef SegName, uint64_t SegVMAddr, uint64_t SegVMSize) {
172 assert(SegName.size() <= sizeof(Seg.segname) && "too long segment name");
173 memset(&Seg, 0, sizeof(SegmentType));
174 Seg.cmd = CmdType;
175 strncpy(Seg.segname, SegName.data(), SegName.size());
176 Seg.maxprot |=
178 Seg.initprot |=
180 Seg.vmaddr = SegVMAddr;
181 Seg.vmsize = SegVMSize;
182}
183
185 LoadCommand LC;
186 const uint64_t SegVMAddr = nextAvailableSegmentAddress();
187 if (is64Bit())
188 constructSegment(LC.MachOLoadCommand.segment_command_64_data,
189 MachO::LC_SEGMENT_64, SegName, SegVMAddr, SegVMSize);
190 else
191 constructSegment(LC.MachOLoadCommand.segment_command_data,
192 MachO::LC_SEGMENT, SegName, SegVMAddr, SegVMSize);
193
194 LoadCommands.push_back(std::move(LC));
195 return LoadCommands.back();
196}
197
198/// Extracts a segment name from a string which is possibly non-null-terminated.
199static StringRef extractSegmentName(const char *SegName) {
200 return StringRef(SegName,
201 strnlen(SegName, sizeof(MachO::segment_command::segname)));
202}
203
204std::optional<StringRef> LoadCommand::getSegmentName() const {
206 switch (MLC.load_command_data.cmd) {
207 case MachO::LC_SEGMENT:
208 return extractSegmentName(MLC.segment_command_data.segname);
209 case MachO::LC_SEGMENT_64:
210 return extractSegmentName(MLC.segment_command_64_data.segname);
211 default:
212 return std::nullopt;
213 }
214}
215
216std::optional<uint64_t> LoadCommand::getSegmentVMAddr() const {
218 switch (MLC.load_command_data.cmd) {
219 case MachO::LC_SEGMENT:
220 return MLC.segment_command_data.vmaddr;
221 case MachO::LC_SEGMENT_64:
222 return MLC.segment_command_64_data.vmaddr;
223 default:
224 return std::nullopt;
225 }
226}
ReachingDefAnalysis InstSet & ToRemove
T Content
uint64_t Addr
uint64_t Size
bool End
Definition: ELF_riscv.cpp:469
Symbol * Sym
Definition: ELF_riscv.cpp:468
#define I(x, y, z)
Definition: MD5.cpp:58
static void constructSegment(SegmentType &Seg, llvm::MachO::LoadCommandType CmdType, StringRef SegName, uint64_t SegVMAddr, uint64_t SegVMSize)
static StringRef extractSegmentName(const char *SegName)
Extracts a segment name from a string which is possibly non-null-terminated.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
bool IsDead
This file defines the SmallPtrSet class.
size_type count(const_arg_type_t< KeyT > Val) const
Return 1 if the specified key is in the map, 0 otherwise.
Definition: DenseMap.h:151
Lightweight error class with error context and mandatory checking.
Definition: Error.h:160
static ErrorSuccess success()
Create a success value.
Definition: Error.h:334
size_type count(ConstPtrType Ptr) const
count - Return 1 if the specified pointer is in the set, 0 otherwise.
Definition: SmallPtrSet.h:384
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
Definition: SmallPtrSet.h:366
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements.
Definition: SmallPtrSet.h:451
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
constexpr size_t size() const
size - Get the string size.
Definition: StringRef.h:137
const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:131
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
An efficient, type-erasing, non-owning reference to a callable.
@ VM_PROT_EXECUTE
Definition: MachO.h:496
@ VM_PROT_READ
Definition: MachO.h:496
@ VM_PROT_WRITE
Definition: MachO.h:496
LoadCommandType
Definition: MachO.h:98
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Error createStringError(std::error_code EC, char const *Fmt, const Ts &... Vals)
Create formatted StringError object.
Definition: Error.h:1244
void erase_if(Container &C, UnaryPredicate P)
Provide a container algorithm similar to C++ Library Fundamentals v2's erase_if which is equivalent t...
Definition: STLExtras.h:2021
MachO::macho_load_command MachOLoadCommand
Definition: MachOObject.h:82
std::optional< StringRef > getSegmentName() const
std::optional< uint64_t > getSegmentVMAddr() const
std::optional< size_t > FunctionStartsCommandIndex
The index LC_FUNCTION_STARTS load command if present.
Definition: MachOObject.h:335
Error removeLoadCommands(function_ref< bool(const LoadCommand &)> ToRemove)
Definition: MachOObject.cpp:91
std::optional< size_t > ChainedFixupsCommandIndex
The index LC_DYLD_CHAINED_FIXUPS load command if present.
Definition: MachOObject.h:337
std::optional< size_t > ExportsTrieCommandIndex
The index LC_DYLD_EXPORTS_TRIE load command if present.
Definition: MachOObject.h:339
Error removeSections(function_ref< bool(const std::unique_ptr< Section > &)> ToRemove)
std::optional< size_t > DylibCodeSignDRsIndex
The index of LC_DYLIB_CODE_SIGN_DRS load command if present.
Definition: MachOObject.h:323
std::optional< size_t > SymTabCommandIndex
The index of LC_SYMTAB load command if present.
Definition: MachOObject.h:325
std::optional< size_t > DyLdInfoCommandIndex
The index of LC_DYLD_INFO or LC_DYLD_INFO_ONLY load command if present.
Definition: MachOObject.h:327
std::vector< LoadCommand > LoadCommands
Definition: MachOObject.h:300
std::optional< size_t > DataInCodeCommandIndex
The index LC_DATA_IN_CODE load command if present.
Definition: MachOObject.h:331
std::optional< size_t > DySymTabCommandIndex
The index LC_DYSYMTAB load command if present.
Definition: MachOObject.h:329
std::optional< size_t > TextSegmentCommandIndex
The index of the LC_SEGMENT or LC_SEGMENT_64 load command corresponding to the __TEXT segment.
Definition: MachOObject.h:342
uint64_t nextAvailableSegmentAddress() const
std::optional< size_t > CodeSignatureCommandIndex
The index of LC_CODE_SIGNATURE load command if present.
Definition: MachOObject.h:321
LoadCommand & addSegment(StringRef SegName, uint64_t SegVMSize)
Creates a new segment load command in the object and returns a reference to the newly created load co...
std::optional< size_t > LinkerOptimizationHintCommandIndex
The index of LC_LINKER_OPTIMIZATIN_HINT load command if present.
Definition: MachOObject.h:333
Section(StringRef SegName, StringRef SectName)
Definition: MachOObject.cpp:16
The location of the symbol table inside the binary is described by LC_SYMTAB load command.
Definition: MachOObject.h:134
const SymbolEntry * getSymbolByIndex(uint32_t Index) const
Definition: MachOObject.cpp:25
std::vector< std::unique_ptr< SymbolEntry > > Symbols
Definition: MachOObject.h:135
void removeSymbols(function_ref< bool(const std::unique_ptr< SymbolEntry > &)> ToRemove)
Definition: MachOObject.cpp:35