From a4c29b6e55c9d4ef44a51c45c6785e8b4fe9deed Mon Sep 17 00:00:00 2001 From: Argyrios Kyrtzidis Date: Mon, 20 Feb 2012 23:58:07 +0000 Subject: [PATCH] [PCH] Recover gracefully if the ASTReader detects that a file is different from the one stored in the PCH/AST, while trying to load a SLocEntry. We verify that all files of the PCH did not change before loading it but this is not enough because: - The AST may have been 1) kept around, 2) to do queries on it. - We may have 1) verified the PCH and 2) started parsing. Between 1) and 2) files may change and we are going to have crashes because the rest of clang cannot deal with the ASTReader failing to read a SLocEntry. Handle this by recovering gracefully in such a case, by initializing the SLocEntry with the info from the PCH/AST as well as reporting failure by the ASTReader. rdar://10888929 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151004 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/clang/Basic/SourceManager.h | 18 ++++++++++----- lib/Basic/SourceManager.cpp | 35 ++++++++++++++++++++++++++++- lib/Serialization/ASTReader.cpp | 9 +++++++- 3 files changed, 54 insertions(+), 8 deletions(-) diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h index 685e318143..bcb2d561a4 100644 --- a/include/clang/Basic/SourceManager.h +++ b/include/clang/Basic/SourceManager.h @@ -519,7 +519,7 @@ class SourceManager : public RefCountedBase { /// /// Negative FileIDs are indexes into this table. To get from ID to an index, /// use (-ID - 2). - std::vector LoadedSLocEntryTable; + mutable std::vector LoadedSLocEntryTable; /// \brief The starting offset of the next local SLocEntry. /// @@ -576,6 +576,8 @@ class SourceManager : public RefCountedBase { // Cache for the "fake" buffer used for error-recovery purposes. mutable llvm::MemoryBuffer *FakeBufferForRecovery; + mutable SrcMgr::ContentCache *FakeContentCacheForRecovery; + /// \brief Lazily computed map of macro argument chunks to their expanded /// source location. typedef std::map MacroArgsMap; @@ -1260,9 +1262,9 @@ public: const SrcMgr::SLocEntry &getLoadedSLocEntry(unsigned Index, bool *Invalid = 0) const { assert(Index < LoadedSLocEntryTable.size() && "Invalid index"); - if (!SLocEntryLoaded[Index]) - ExternalSLocEntries->ReadSLocEntry(-(static_cast(Index) + 2)); - return LoadedSLocEntryTable[Index]; + if (SLocEntryLoaded[Index]) + return LoadedSLocEntryTable[Index]; + return loadSLocEntry(Index, Invalid); } const SrcMgr::SLocEntry &getSLocEntry(FileID FID, bool *Invalid = 0) const { @@ -1313,6 +1315,9 @@ public: private: const llvm::MemoryBuffer *getFakeBufferForRecovery() const; + const SrcMgr::ContentCache *getFakeContentCacheForRecovery() const; + + const SrcMgr::SLocEntry &loadSLocEntry(unsigned Index, bool *Invalid) const; /// \brief Get the entry with the given unwrapped FileID. const SrcMgr::SLocEntry &getSLocEntryByID(int ID) const { @@ -1322,8 +1327,9 @@ private: return getLocalSLocEntry(static_cast(ID)); } - const SrcMgr::SLocEntry &getLoadedSLocEntryByID(int ID) const { - return getLoadedSLocEntry(static_cast(-ID - 2)); + const SrcMgr::SLocEntry &getLoadedSLocEntryByID(int ID, + bool *Invalid = 0) const { + return getLoadedSLocEntry(static_cast(-ID - 2), Invalid); } /// createExpansionLoc - Implements the common elements of storing an diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp index 61f4e86652..a2540bc18a 100644 --- a/lib/Basic/SourceManager.cpp +++ b/lib/Basic/SourceManager.cpp @@ -370,7 +370,8 @@ LineTableInfo &SourceManager::getLineTable() { SourceManager::SourceManager(DiagnosticsEngine &Diag, FileManager &FileMgr) : Diag(Diag), FileMgr(FileMgr), OverridenFilesKeepOriginalName(true), ExternalSLocEntries(0), LineTable(0), NumLinearScans(0), - NumBinaryProbes(0), FakeBufferForRecovery(0) { + NumBinaryProbes(0), FakeBufferForRecovery(0), + FakeContentCacheForRecovery(0) { clearIDTables(); Diag.setSourceManager(this); } @@ -396,6 +397,7 @@ SourceManager::~SourceManager() { } delete FakeBufferForRecovery; + delete FakeContentCacheForRecovery; for (llvm::DenseMap::iterator I = MacroArgsCacheMap.begin(),E = MacroArgsCacheMap.end(); I!=E; ++I) { @@ -469,6 +471,25 @@ SourceManager::createMemBufferContentCache(const MemoryBuffer *Buffer) { return Entry; } +const SrcMgr::SLocEntry &SourceManager::loadSLocEntry(unsigned Index, + bool *Invalid) const { + assert(!SLocEntryLoaded[Index]); + if (ExternalSLocEntries->ReadSLocEntry(-(static_cast(Index) + 2))) { + if (Invalid) + *Invalid = true; + // If the file of the SLocEntry changed we could still have loaded it. + if (!SLocEntryLoaded[Index]) { + // Try to recover; create a SLocEntry so the rest of clang can handle it. + LoadedSLocEntryTable[Index] = SLocEntry::get(0, + FileInfo::get(SourceLocation(), + getFakeContentCacheForRecovery(), + SrcMgr::C_User)); + } + } + + return LoadedSLocEntryTable[Index]; +} + std::pair SourceManager::AllocateLoadedSLocEntries(unsigned NumSLocEntries, unsigned TotalSize) { @@ -491,6 +512,18 @@ const llvm::MemoryBuffer *SourceManager::getFakeBufferForRecovery() const { return FakeBufferForRecovery; } +/// \brief As part of recovering from missing or changed content, produce a +/// fake content cache. +const SrcMgr::ContentCache * +SourceManager::getFakeContentCacheForRecovery() const { + if (!FakeContentCacheForRecovery) { + FakeContentCacheForRecovery = new ContentCache(); + FakeContentCacheForRecovery->replaceBuffer(getFakeBufferForRecovery(), + /*DoNotFree=*/true); + } + return FakeContentCacheForRecovery; +} + //===----------------------------------------------------------------------===// // Methods to create new FileID's and macro expansions. //===----------------------------------------------------------------------===// diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp index 75b5d68ce6..dde54d6b79 100644 --- a/lib/Serialization/ASTReader.cpp +++ b/lib/Serialization/ASTReader.cpp @@ -1111,6 +1111,10 @@ ASTReader::ASTReadResult ASTReader::ReadSLocEntryRecord(int ID) { return Failure; } + // We will detect whether a file changed and return 'Failure' for it, but + // we will also try to fail gracefully by setting up the SLocEntry. + ASTReader::ASTReadResult Result = Success; + bool OverriddenBuffer = Record[6]; std::string OrigFilename(BlobStart, BlobStart + BlobLen); @@ -1149,7 +1153,7 @@ ASTReader::ASTReadResult ASTReader::ReadSLocEntryRecord(int ID) { #endif )) { Error(diag::err_fe_pch_file_modified, Filename); - return Failure; + Result = Failure; } SourceLocation IncludeLoc = ReadSourceLocation(*F, Record[1]); @@ -1193,6 +1197,9 @@ ASTReader::ASTReadResult ASTReader::ReadSLocEntryRecord(int ID) { Filename); SourceMgr.overrideFileContents(File, Buffer); } + + if (Result == Failure) + return Failure; break; } -- 2.40.0