From 205ca68b8db35f3f6037aac8006d8cf29be2701a Mon Sep 17 00:00:00 2001 From: Nico Weber Date: Sat, 15 Sep 2018 18:35:51 +0000 Subject: [PATCH] Give InfoStreamBuilder an opt-in method to write a hash of the PDB as GUID. Naively computing the hash after the PDB data has been generated is in practice as fast as other approaches I tried. I also tried online-computing the hash as parts of the PDB were written out (https://reviews.llvm.org/D51887; that's also where all the measuring data is) and computing the hash in parallel (https://reviews.llvm.org/D51957). This approach here is simplest, without being slower. Differential Revision: https://reviews.llvm.org/D51956 llvm-svn: 342333 --- .../llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h | 11 +++++++- .../llvm/DebugInfo/PDB/Native/PDBFileBuilder.h | 4 ++- .../lib/DebugInfo/PDB/Native/InfoStreamBuilder.cpp | 11 ++++++-- llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp | 33 +++++++++++++++++----- llvm/tools/llvm-pdbutil/llvm-pdbutil.cpp | 7 +++-- 5 files changed, 52 insertions(+), 14 deletions(-) diff --git a/llvm/include/llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h b/llvm/include/llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h index 419e8ad..101127a 100644 --- a/llvm/include/llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h +++ b/llvm/include/llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h @@ -35,11 +35,18 @@ public: InfoStreamBuilder &operator=(const InfoStreamBuilder &) = delete; void setVersion(PdbRaw_ImplVer V); + void addFeature(PdbRaw_FeatureSig Sig); + + // If this is true, the PDB contents are hashed and this hash is used as + // PDB GUID and as Signature. The age is always 1. + void setHashPDBContentsToGUID(bool B); + + // These only have an effect if hashPDBContentsToGUID() is false. void setSignature(uint32_t S); void setAge(uint32_t A); void setGuid(codeview::GUID G); - void addFeature(PdbRaw_FeatureSig Sig); + bool hashPDBContentsToGUID() const { return HashPDBContentsToGUID; } uint32_t getAge() const { return Age; } codeview::GUID getGuid() const { return Guid; } Optional getSignature() const { return Signature; } @@ -60,6 +67,8 @@ private: Optional Signature; codeview::GUID Guid; + bool HashPDBContentsToGUID = false; + NamedStreamMap &NamedStreams; }; } diff --git a/llvm/include/llvm/DebugInfo/PDB/Native/PDBFileBuilder.h b/llvm/include/llvm/DebugInfo/PDB/Native/PDBFileBuilder.h index 7f9c4cf..3745874 100644 --- a/llvm/include/llvm/DebugInfo/PDB/Native/PDBFileBuilder.h +++ b/llvm/include/llvm/DebugInfo/PDB/Native/PDBFileBuilder.h @@ -53,7 +53,9 @@ public: PDBStringTableBuilder &getStringTableBuilder(); GSIStreamBuilder &getGsiBuilder(); - Error commit(StringRef Filename); + // If HashPDBContentsToGUID is true on the InfoStreamBuilder, Guid is filled + // with the computed PDB GUID on return. + Error commit(StringRef Filename, codeview::GUID *Guid); Expected getNamedStreamIndex(StringRef Name) const; Error addNamedStream(StringRef Name, StringRef Data); diff --git a/llvm/lib/DebugInfo/PDB/Native/InfoStreamBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/InfoStreamBuilder.cpp index 54d6835..3b5a2ac 100644 --- a/llvm/lib/DebugInfo/PDB/Native/InfoStreamBuilder.cpp +++ b/llvm/lib/DebugInfo/PDB/Native/InfoStreamBuilder.cpp @@ -32,15 +32,20 @@ InfoStreamBuilder::InfoStreamBuilder(msf::MSFBuilder &Msf, void InfoStreamBuilder::setVersion(PdbRaw_ImplVer V) { Ver = V; } +void InfoStreamBuilder::addFeature(PdbRaw_FeatureSig Sig) { + Features.push_back(Sig); +} + +void InfoStreamBuilder::setHashPDBContentsToGUID(bool B) { + HashPDBContentsToGUID = B; +} + void InfoStreamBuilder::setAge(uint32_t A) { Age = A; } void InfoStreamBuilder::setSignature(uint32_t S) { Signature = S; } void InfoStreamBuilder::setGuid(GUID G) { Guid = G; } -void InfoStreamBuilder::addFeature(PdbRaw_FeatureSig Sig) { - Features.push_back(Sig); -} Error InfoStreamBuilder::finalizeMsfLayout() { uint32_t Length = sizeof(InfoStreamHeader) + diff --git a/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp index 1612d74e..e0ceb74 100644 --- a/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp +++ b/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp @@ -25,6 +25,7 @@ #include "llvm/Support/BinaryStreamWriter.h" #include "llvm/Support/JamCRC.h" #include "llvm/Support/Path.h" +#include "llvm/Support/xxhash.h" using namespace llvm; using namespace llvm::codeview; @@ -261,13 +262,14 @@ void PDBFileBuilder::commitInjectedSources(WritableBinaryStream &MsfBuffer, } } -Error PDBFileBuilder::commit(StringRef Filename) { +Error PDBFileBuilder::commit(StringRef Filename, codeview::GUID *Guid) { assert(!Filename.empty()); if (auto EC = finalizeMsfLayout()) return EC; MSFLayout Layout; - auto ExpectedMsfBuffer = Msf->commit(Filename, Layout); + Expected ExpectedMsfBuffer = + Msf->commit(Filename, Layout); if (!ExpectedMsfBuffer) return ExpectedMsfBuffer.takeError(); FileBufferByteStream Buffer = std::move(*ExpectedMsfBuffer); @@ -329,11 +331,28 @@ Error PDBFileBuilder::commit(StringRef Filename) { // Set the build id at the very end, after every other byte of the PDB // has been written. - // FIXME: Use a hash of the PDB rather than time(nullptr) for the signature. - H->Age = Info->getAge(); - H->Guid = Info->getGuid(); - Optional Sig = Info->getSignature(); - H->Signature = Sig.hasValue() ? *Sig : time(nullptr); + if (Info->hashPDBContentsToGUID()) { + // Compute a hash of all sections of the output file. + uint64_t Digest = + xxHash64({Buffer.getBufferStart(), Buffer.getBufferEnd()}); + + H->Age = 1; + + memcpy(H->Guid.Guid, &Digest, 8); + // xxhash only gives us 8 bytes, so put some fixed data in the other half. + memcpy(H->Guid.Guid + 8, "LLD PDB.", 8); + + // Put the hash in the Signature field too. + H->Signature = static_cast(Digest); + + // Return GUID to caller. + memcpy(Guid, H->Guid.Guid, 16); + } else { + H->Age = Info->getAge(); + H->Guid = Info->getGuid(); + Optional Sig = Info->getSignature(); + H->Signature = Sig.hasValue() ? *Sig : time(nullptr); + } return Buffer.commit(); } diff --git a/llvm/tools/llvm-pdbutil/llvm-pdbutil.cpp b/llvm/tools/llvm-pdbutil/llvm-pdbutil.cpp index 7c34cc6..f2adacd 100644 --- a/llvm/tools/llvm-pdbutil/llvm-pdbutil.cpp +++ b/llvm/tools/llvm-pdbutil/llvm-pdbutil.cpp @@ -803,7 +803,8 @@ static void yamlToPdb(StringRef Path) { Builder.getStringTableBuilder().setStrings(*Strings.strings()); - ExitOnErr(Builder.commit(opts::yaml2pdb::YamlPdbOutputFile)); + codeview::GUID IgnoredOutGuid; + ExitOnErr(Builder.commit(opts::yaml2pdb::YamlPdbOutputFile, &IgnoredOutGuid)); } static PDBFile &loadPDB(StringRef Path, std::unique_ptr &Session) { @@ -1263,7 +1264,9 @@ static void mergePdbs() { OutFile = opts::merge::InputFilenames[0]; llvm::sys::path::replace_extension(OutFile, "merged.pdb"); } - ExitOnErr(Builder.commit(OutFile)); + + codeview::GUID IgnoredOutGuid; + ExitOnErr(Builder.commit(OutFile, &IgnoredOutGuid)); } static void explain() { -- 2.7.4