LLVM 19.0.0git
PublicsStream.cpp
Go to the documentation of this file.
1//===- PublicsStream.cpp - PDB Public Symbol Stream -----------------------===//
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// The data structures defined in this file are based on the reference
10// implementation which is available at
11// https://github.com/Microsoft/microsoft-pdb/blob/master/PDB/dbi/gsi.h
12//
13// When you are reading the reference source code, you'd find the
14// information below useful.
15//
16// - ppdb1->m_fMinimalDbgInfo seems to be always true.
17// - SMALLBUCKETS macro is defined.
18//
19// The reference doesn't compile, so I learned just by reading code.
20// It's not guaranteed to be correct.
21//
22//===----------------------------------------------------------------------===//
23
29#include "llvm/Support/Error.h"
30#include <cstdint>
31
32using namespace llvm;
33using namespace llvm::msf;
34using namespace llvm::support;
35using namespace llvm::pdb;
36
37PublicsStream::PublicsStream(std::unique_ptr<MappedBlockStream> Stream)
38 : Stream(std::move(Stream)) {}
39
41
42uint32_t PublicsStream::getSymHash() const { return Header->SymHash; }
44 return Header->ISectThunkTable;
45}
47 return Header->OffThunkTable;
48}
49
50// Publics stream contains fixed-size headers and a serialized hash table.
51// This implementation is not complete yet. It reads till the end of the
52// stream so that we verify the stream is at least not corrupted. However,
53// we skip over the hash table which we believe contains information about
54// public symbols.
56 BinaryStreamReader Reader(*Stream);
57
58 // Check stream size.
59 if (Reader.bytesRemaining() <
60 sizeof(PublicsStreamHeader) + sizeof(GSIHashHeader))
61 return make_error<RawError>(raw_error_code::corrupt_file,
62 "Publics Stream does not contain a header.");
63
64 // Read PSGSIHDR struct.
65 if (Reader.readObject(Header))
66 return make_error<RawError>(raw_error_code::corrupt_file,
67 "Publics Stream does not contain a header.");
68
69 // Read the hash table.
70 if (auto E = PublicsTable.read(Reader))
71 return E;
72
73 // Something called "address map" follows.
74 uint32_t NumAddressMapEntries = Header->AddrMap / sizeof(uint32_t);
75 if (auto EC = Reader.readArray(AddressMap, NumAddressMapEntries))
76 return joinErrors(std::move(EC),
77 make_error<RawError>(raw_error_code::corrupt_file,
78 "Could not read an address map."));
79
80 // Something called "thunk map" follows.
81 if (auto EC = Reader.readArray(ThunkMap, Header->NumThunks))
82 return joinErrors(std::move(EC),
83 make_error<RawError>(raw_error_code::corrupt_file,
84 "Could not read a thunk map."));
85
86 // Something called "section map" follows.
87 if (Reader.bytesRemaining() > 0) {
88 if (auto EC = Reader.readArray(SectionOffsets, Header->NumSections))
89 return joinErrors(std::move(EC),
90 make_error<RawError>(raw_error_code::corrupt_file,
91 "Could not read a section map."));
92 }
93
94 if (Reader.bytesRemaining() > 0)
95 return make_error<RawError>(raw_error_code::corrupt_file,
96 "Corrupted publics stream.");
97 return Error::success();
98}
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
Provides read only access to a subclass of BinaryStream.
Error readObject(const T *&Dest)
Get a pointer to an object of type T from the underlying stream, as if by memcpy, and store the resul...
uint64_t bytesRemaining() const
Error readArray(ArrayRef< T > &Array, uint32_t NumElements)
Get a reference to a NumElements element array of objects of type T from the underlying stream as if ...
Lightweight error class with error context and mandatory checking.
Definition: Error.h:160
static ErrorSuccess success()
Create a success value.
Definition: Error.h:334
Error read(BinaryStreamReader &Reader)
uint32_t getSymHash() const
uint32_t getThunkTableOffset() const
PublicsStream(std::unique_ptr< msf::MappedBlockStream > Stream)
uint16_t getThunkTableSection() const
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Error joinErrors(Error E1, Error E2)
Concatenate errors.
Definition: Error.h:431
OutputIt move(R &&Range, OutputIt Out)
Provide wrappers to std::move which take ranges instead of having to pass begin/end explicitly.
Definition: STLExtras.h:1858
Implement std::hash so that hash_code can be used in STL containers.
Definition: BitVector.h:858
Header of the hash tables found in the globals and publics sections.
Definition: RawTypes.h:28
support::ulittle32_t OffThunkTable
Definition: RawTypes.h:271
support::ulittle32_t AddrMap
Definition: RawTypes.h:266
support::ulittle32_t NumThunks
Definition: RawTypes.h:267
support::ulittle32_t SymHash
Definition: RawTypes.h:265
support::ulittle16_t ISectThunkTable
Definition: RawTypes.h:269
support::ulittle32_t NumSections
Definition: RawTypes.h:272