jansvoboda11 updated this revision to Diff 552897.
jansvoboda11 added a comment.
Early return.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D158573/new/
https://reviews.llvm.org/D158573
Files:
clang/include/clang/Basic/Module.h
clang/include/clang/Serialization/ASTBitCodes.h
clang/include/clang/Serialization/ASTWriter.h
clang/lib/Serialization/ASTReader.cpp
clang/lib/Serialization/ASTWriter.cpp
clang/lib/Serialization/GlobalModuleIndex.cpp
clang/test/Modules/ASTSignature.c
Index: clang/test/Modules/ASTSignature.c
===================================================================
--- clang/test/Modules/ASTSignature.c
+++ clang/test/Modules/ASTSignature.c
@@ -1,6 +1,6 @@
// RUN: rm -rf %t
-// RUN: %clang_cc1 -iquote %S/Inputs/ASTHash/ -fsyntax-only -fmodules \
-// RUN: -fimplicit-module-maps -fmodules-strict-context-hash \
+// RUN: %clang_cc1 -iquote %S/Inputs/ASTHash/ -fsyntax-only \
+// RUN: -fmodules -fimplicit-module-maps -fmodules-strict-context-hash \
// RUN: -fmodules-cache-path=%t -fdisable-module-hash %s
// RUN: cp %t/MyHeader2.pcm %t1.pcm
// RUN: rm -rf %t
@@ -8,17 +8,18 @@
// RUN: -fmodules -fimplicit-module-maps -fmodules-strict-context-hash \
// RUN: -fmodules-cache-path=%t -fdisable-module-hash %s
// RUN: cp %t/MyHeader2.pcm %t2.pcm
-// RUN: llvm-bcanalyzer --dump --disable-histogram %t1.pcm > %t1.dump
-// RUN: llvm-bcanalyzer --dump --disable-histogram %t2.pcm > %t2.dump
+// RUN: llvm-bcanalyzer --dump --disable-histogram --show-binary-blobs %t1.pcm > %t1.dump
+// RUN: llvm-bcanalyzer --dump --disable-histogram --show-binary-blobs %t2.pcm > %t2.dump
// RUN: cat %t1.dump %t2.dump | FileCheck %s
#include "my_header_2.h"
my_int var = 42;
-// CHECK: [[AST_BLOCK_HASH:<AST_BLOCK_HASH .*>]]
-// CHECK: [[SIGNATURE:<SIGNATURE .*>]]
-// CHECK: [[AST_BLOCK_HASH]]
-// CHECK-NOT: [[SIGNATURE]]
-// The modules built by this test are designed to yield the same AST. If this
-// test fails, it means that the AST block is has become non-relocatable.
+// CHECK: <AST_BLOCK_HASH abbrevid={{[0-9]+}}/> blob data = '[[AST_BLOCK_HASH:.*]]'
+// CHECK: <SIGNATURE abbrevid={{[0-9]+}}/> blob data = '[[SIGNATURE:.*]]'
+// CHECK: <AST_BLOCK_HASH abbrevid={{[0-9]+}}/> blob data = '[[AST_BLOCK_HASH]]'
+// CHECK-NOT: <SIGNATURE abbrevid={{[0-9]+}}/> blob data = '[[SIGNATURE]]'
+// The modules built by this test are designed to yield the same AST but distinct AST files.
+// If this test fails, it means that either the AST block has become non-relocatable,
+// or the file signature stopped hashing some parts of the AST file.
Index: clang/lib/Serialization/GlobalModuleIndex.cpp
===================================================================
--- clang/lib/Serialization/GlobalModuleIndex.cpp
+++ clang/lib/Serialization/GlobalModuleIndex.cpp
@@ -15,6 +15,7 @@
#include "clang/Basic/FileManager.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Serialization/ASTBitCodes.h"
+#include "clang/Serialization/ASTReader.h"
#include "clang/Serialization/ModuleFile.h"
#include "clang/Serialization/PCHContainerOperations.h"
#include "llvm/ADT/DenseMap.h"
@@ -697,9 +698,12 @@
}
// Get Signature.
- if (State == DiagnosticOptionsBlock && Code == SIGNATURE)
- getModuleFileInfo(File).Signature = ASTFileSignature::create(
- Record.begin(), Record.begin() + ASTFileSignature::size);
+ if (State == DiagnosticOptionsBlock && Code == SIGNATURE) {
+ auto Signature = ASTFileSignature::create(Blob.begin(), Blob.end());
+ assert(Signature != ASTFileSignature::createDummy() &&
+ "Dummy AST file signature not backpatched in ASTWriter.");
+ getModuleFileInfo(File).Signature = Signature;
+ }
// We don't care about this record.
}
Index: clang/lib/Serialization/ASTWriter.cpp
===================================================================
--- clang/lib/Serialization/ASTWriter.cpp
+++ clang/lib/Serialization/ASTWriter.cpp
@@ -1120,50 +1120,96 @@
}
std::pair<ASTFileSignature, ASTFileSignature>
-ASTWriter::createSignature(StringRef AllBytes, StringRef ASTBlockBytes) {
+ASTWriter::createSignature() const {
+ StringRef AllBytes(Buffer.data(), Buffer.size());
+
llvm::SHA1 Hasher;
- Hasher.update(ASTBlockBytes);
+ Hasher.update(AllBytes.slice(ASTBlockRange.first, ASTBlockRange.second));
ASTFileSignature ASTBlockHash = ASTFileSignature::create(Hasher.result());
- // Add the remaining bytes (i.e. bytes before the unhashed control block that
- // are not part of the AST block).
- Hasher.update(
- AllBytes.take_front(ASTBlockBytes.bytes_end() - AllBytes.bytes_begin()));
+ // Add the remaining bytes:
+ // 1. Before the unhashed control block.
+ Hasher.update(AllBytes.slice(0, UnhashedControlBlockRange.first));
+ // 2. Between the unhashed control block and the AST block.
Hasher.update(
- AllBytes.take_back(AllBytes.bytes_end() - ASTBlockBytes.bytes_end()));
+ AllBytes.slice(UnhashedControlBlockRange.second, ASTBlockRange.first));
+ // 3. After the AST block.
+ Hasher.update(AllBytes.slice(ASTBlockRange.second, StringRef::npos));
ASTFileSignature Signature = ASTFileSignature::create(Hasher.result());
return std::make_pair(ASTBlockHash, Signature);
}
-ASTFileSignature ASTWriter::writeUnhashedControlBlock(Preprocessor &PP,
- ASTContext &Context) {
+ASTFileSignature ASTWriter::backpatchSignature() {
+ if (!WritingModule ||
+ !PP->getHeaderSearchInfo().getHeaderSearchOpts().ModulesHashContent)
+ return {};
+
+ // For implicit modules, write the hash of the PCM as its signature.
+ ASTFileSignature Signature;
+ auto BackpatchSignatureAt = [&](const ASTFileSignature &S, uint64_t BitNo) {
+ using WordT = unsigned;
+ std::array<WordT, sizeof(ASTFileSignature) / sizeof(WordT)> Words;
+ static_assert(sizeof(Words) == sizeof(S));
+ std::memcpy(Words.data(), S.data(), sizeof(ASTFileSignature));
+ for (WordT Word : Words) {
+ Stream.BackpatchWord(BitNo, Word);
+ BitNo += sizeof(WordT) * 8;
+ }
+ };
+
+ ASTFileSignature ASTBlockHash;
+ std::tie(ASTBlockHash, Signature) = createSignature();
+
+ BackpatchSignatureAt(ASTBlockHash, ASTBlockHashOffset);
+ BackpatchSignatureAt(Signature, SignatureOffset);
+
+ return Signature;
+}
+
+void ASTWriter::writeUnhashedControlBlock(Preprocessor &PP,
+ ASTContext &Context) {
using namespace llvm;
// Flush first to prepare the PCM hash (signature).
Stream.FlushToWord();
- auto StartOfUnhashedControl = Stream.GetCurrentBitNo() >> 3;
+ UnhashedControlBlockRange.first = Stream.GetCurrentBitNo() >> 3;
// Enter the block and prepare to write records.
RecordData Record;
Stream.EnterSubblock(UNHASHED_CONTROL_BLOCK_ID, 5);
// For implicit modules, write the hash of the PCM as its signature.
- ASTFileSignature Signature;
if (WritingModule &&
PP.getHeaderSearchInfo().getHeaderSearchOpts().ModulesHashContent) {
- ASTFileSignature ASTBlockHash;
- auto ASTBlockStartByte = ASTBlockRange.first >> 3;
- auto ASTBlockByteLength = (ASTBlockRange.second >> 3) - ASTBlockStartByte;
- std::tie(ASTBlockHash, Signature) = createSignature(
- StringRef(Buffer.begin(), StartOfUnhashedControl),
- StringRef(Buffer.begin() + ASTBlockStartByte, ASTBlockByteLength));
-
- Record.append(ASTBlockHash.begin(), ASTBlockHash.end());
- Stream.EmitRecord(AST_BLOCK_HASH, Record);
+ // At this point, we don't know the actual signature of the file or the AST
+ // block - we're only able to compute those at the end of the serialization
+ // process. Let's store dummy signatures for now, and replace them with the
+ // real ones later on.
+ // The bitstream VBR-encodes record elements, which makes backpatching them
+ // really difficult. Let's store the signatures as blobs instead - they are
+ // guaranteed to be word-aligned, and we control their format/encoding.
+ auto Dummy = ASTFileSignature::createDummy();
+ SmallString<128> Blob{Dummy.begin(), Dummy.end()};
+
+ auto Abbrev = std::make_shared<BitCodeAbbrev>();
+ Abbrev->Add(BitCodeAbbrevOp(AST_BLOCK_HASH));
+ Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
+ unsigned ASTBlockHashAbbrev = Stream.EmitAbbrev(std::move(Abbrev));
+
+ Abbrev = std::make_shared<BitCodeAbbrev>();
+ Abbrev->Add(BitCodeAbbrevOp(SIGNATURE));
+ Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
+ unsigned SignatureAbbrev = Stream.EmitAbbrev(std::move(Abbrev));
+
+ Record.push_back(AST_BLOCK_HASH);
+ Stream.EmitRecordWithBlob(ASTBlockHashAbbrev, Record, Blob);
+ ASTBlockHashOffset = Stream.GetCurrentBitNo() - Blob.size() * 8;
Record.clear();
- Record.append(Signature.begin(), Signature.end());
- Stream.EmitRecord(SIGNATURE, Record);
+
+ Record.push_back(SIGNATURE);
+ Stream.EmitRecordWithBlob(SignatureAbbrev, Record, Blob);
+ SignatureOffset = Stream.GetCurrentBitNo() - Blob.size() * 8;
Record.clear();
}
@@ -1232,7 +1278,7 @@
// Leave the options block.
Stream.ExitBlock();
- return Signature;
+ UnhashedControlBlockRange.second = Stream.GetCurrentBitNo() >> 3;
}
/// Write the control block.
@@ -4690,6 +4736,7 @@
ASTContext &Context = SemaRef.Context;
Preprocessor &PP = SemaRef.PP;
+ writeUnhashedControlBlock(PP, Context);
collectNonAffectingInputFiles();
@@ -4838,7 +4885,7 @@
// Write the remaining AST contents.
Stream.FlushToWord();
- ASTBlockRange.first = Stream.GetCurrentBitNo();
+ ASTBlockRange.first = Stream.GetCurrentBitNo() >> 3;
Stream.EnterSubblock(AST_BLOCK_ID, 5);
ASTBlockStartOffset = Stream.GetCurrentBitNo();
@@ -5191,13 +5238,13 @@
Stream.EmitRecord(STATISTICS, Record);
Stream.ExitBlock();
Stream.FlushToWord();
- ASTBlockRange.second = Stream.GetCurrentBitNo();
+ ASTBlockRange.second = Stream.GetCurrentBitNo() >> 3;
// Write the module file extension blocks.
for (const auto &ExtWriter : ModuleFileExtensionWriters)
WriteModuleFileExtension(SemaRef, *ExtWriter);
- return writeUnhashedControlBlock(PP, Context);
+ return backpatchSignature();
}
void ASTWriter::WriteDeclUpdatesBlocks(RecordDataImpl &OffsetsRecord) {
Index: clang/lib/Serialization/ASTReader.cpp
===================================================================
--- clang/lib/Serialization/ASTReader.cpp
+++ clang/lib/Serialization/ASTReader.cpp
@@ -4734,12 +4734,6 @@
ShouldFinalizePCM = true;
return Success;
- case UNHASHED_CONTROL_BLOCK_ID:
- // This block is handled using look-ahead during ReadControlBlock. We
- // shouldn't get here!
- Error("malformed block record in AST file");
- return Failure;
-
default:
if (llvm::Error Err = Stream.SkipBlock()) {
Error(std::move(Err));
@@ -4859,13 +4853,18 @@
}
switch ((UnhashedControlBlockRecordTypes)MaybeRecordType.get()) {
case SIGNATURE:
- if (F)
- F->Signature = ASTFileSignature::create(Record.begin(), Record.end());
+ if (F) {
+ F->Signature = ASTFileSignature::create(Blob.begin(), Blob.end());
+ assert(F->Signature != ASTFileSignature::createDummy() &&
+ "Dummy AST file signature not backpatched in ASTWriter.");
+ }
break;
case AST_BLOCK_HASH:
- if (F)
- F->ASTBlockHash =
- ASTFileSignature::create(Record.begin(), Record.end());
+ if (F) {
+ F->ASTBlockHash = ASTFileSignature::create(Blob.begin(), Blob.end());
+ assert(F->ASTBlockHash != ASTFileSignature::createDummy() &&
+ "Dummy AST block hash not backpatched in ASTWriter.");
+ }
break;
case DIAGNOSTIC_OPTIONS: {
bool Complain = (ClientLoadCapabilities & ARR_OutOfDate) == 0;
@@ -5167,9 +5166,12 @@
consumeError(MaybeRecord.takeError());
return ASTFileSignature();
}
- if (SIGNATURE == MaybeRecord.get())
- return ASTFileSignature::create(Record.begin(),
- Record.begin() + ASTFileSignature::size);
+ if (SIGNATURE == MaybeRecord.get()) {
+ auto Signature = ASTFileSignature::create(Blob.begin(), Blob.end());
+ assert(Signature != ASTFileSignature::createDummy() &&
+ "Dummy AST file signature not backpatched in ASTWriter.");
+ return Signature;
+ }
}
}
Index: clang/include/clang/Serialization/ASTWriter.h
===================================================================
--- clang/include/clang/Serialization/ASTWriter.h
+++ clang/include/clang/Serialization/ASTWriter.h
@@ -128,10 +128,17 @@
/// The module we're currently writing, if any.
Module *WritingModule = nullptr;
- /// The offset of the first bit inside the AST_BLOCK.
+ /// The byte range representing all the UNHASHED_CONTROL_BLOCK.
+ std::pair<uint64_t, uint64_t> UnhashedControlBlockRange;
+ /// The bit offset of the AST block hash blob.
+ uint64_t ASTBlockHashOffset = 0;
+ /// The bit offset of the signature blob.
+ uint64_t SignatureOffset = 0;
+
+ /// The bit offset of the first bit inside the AST_BLOCK.
uint64_t ASTBlockStartOffset = 0;
- /// The range representing all the AST_BLOCK.
+ /// The byte range representing all the AST_BLOCK.
std::pair<uint64_t, uint64_t> ASTBlockRange;
/// The base directory for any relative paths we emit.
@@ -495,12 +502,11 @@
StringRef isysroot);
/// Write out the signature and diagnostic options, and return the signature.
- ASTFileSignature writeUnhashedControlBlock(Preprocessor &PP,
- ASTContext &Context);
+ void writeUnhashedControlBlock(Preprocessor &PP, ASTContext &Context);
+ ASTFileSignature backpatchSignature();
/// Calculate hash of the pcm content.
- static std::pair<ASTFileSignature, ASTFileSignature>
- createSignature(StringRef AllBytes, StringRef ASTBlockBytes);
+ std::pair<ASTFileSignature, ASTFileSignature> createSignature() const;
void WriteInputFiles(SourceManager &SourceMgr, HeaderSearchOptions &HSOpts);
void WriteSourceManagerBlock(SourceManager &SourceMgr,
Index: clang/include/clang/Serialization/ASTBitCodes.h
===================================================================
--- clang/include/clang/Serialization/ASTBitCodes.h
+++ clang/include/clang/Serialization/ASTBitCodes.h
@@ -41,7 +41,7 @@
/// Version 4 of AST files also requires that the version control branch and
/// revision match exactly, since there is no backward compatibility of
/// AST files at this time.
-const unsigned VERSION_MAJOR = 28;
+const unsigned VERSION_MAJOR = 29;
/// AST file minor version number supported by this version of
/// Clang.
Index: clang/include/clang/Basic/Module.h
===================================================================
--- clang/include/clang/Basic/Module.h
+++ clang/include/clang/Basic/Module.h
@@ -58,7 +58,7 @@
static constexpr size_t size = std::tuple_size<BaseT>::value;
- ASTFileSignature(BaseT S = {{0}}) : BaseT(std::move(S)) {}
+ constexpr ASTFileSignature(BaseT S = {{0}}) : BaseT(std::move(S)) {}
explicit operator bool() const { return *this != BaseT({{0}}); }
@@ -81,6 +81,12 @@
return Sentinel;
}
+ static ASTFileSignature createDummy() {
+ ASTFileSignature Dummy;
+ Dummy.fill(0x00);
+ return Dummy;
+ }
+
template <typename InputIt>
static ASTFileSignature create(InputIt First, InputIt Last) {
assert(std::distance(First, Last) == size &&
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