Implement -fno-validate-pch at the -cc1 level, which suppresses most

of the usual consistency checks used to determine when a precompiled
header is incompatible with the translation unit it's being loaded
into.

Enable this option when loading a precompiled preamble, because the
preamble loader will be performing all of this checking itself. Enable
the preamble-based test now that it's working.

This option is also useful for debugging Clang's PCH
(<rdar://problem/7532213>).

llvm-svn: 109475

5 files changed, 33 insertions, 18 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 7ff3cdc5b9a..0463db18dc0 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -394,6 +394,7 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
     PreprocessorOpts.PrecompiledPreambleBytes.second
                                                     = PreambleEndsAtStartOfLine;
     PreprocessorOpts.ImplicitPCHInclude = PreambleFile.str();
+    PreprocessorOpts.DisablePCHValidation = true;
   }
   
   llvm::OwningPtr<TopLevelDeclTrackerAction> Act;
@@ -415,9 +416,11 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
   Act->EndSourceFile();
 
   // Remove the overridden buffer we used for the preamble.
-  if (OverrideMainBuffer)
+  if (OverrideMainBuffer) {
     PreprocessorOpts.eraseRemappedFile(
                                PreprocessorOpts.remapped_file_buffer_end() - 1);
+    PreprocessorOpts.DisablePCHValidation = true;
+  }
   
   Clang.takeDiagnosticClient();
   
@@ -426,9 +429,11 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
   
 error:
   // Remove the overridden buffer we used for the preamble.
-  if (OverrideMainBuffer)
+  if (OverrideMainBuffer) {
     PreprocessorOpts.eraseRemappedFile(
                                PreprocessorOpts.remapped_file_buffer_end() - 1);
+    PreprocessorOpts.DisablePCHValidation = true;
+  }
   
   Clang.takeSourceManager();
   Clang.takeFileManager();
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 0b1041f8412..ea295687aa0 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -250,9 +250,11 @@ void CompilerInstance::createASTContext() {
 
 // ExternalASTSource
 
-void CompilerInstance::createPCHExternalASTSource(llvm::StringRef Path) {
+void CompilerInstance::createPCHExternalASTSource(llvm::StringRef Path,
+                                                  bool DisablePCHValidation) {
   llvm::OwningPtr<ExternalASTSource> Source;
   Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
+                                          DisablePCHValidation,
                                           getPreprocessor(), getASTContext()));
   // Remember the PCHReader, but in a non-owning way.
   Reader = static_cast<PCHReader*>(Source.get());
@@ -262,11 +264,13 @@ void CompilerInstance::createPCHExternalASTSource(llvm::StringRef Path) {
 ExternalASTSource *
 CompilerInstance::createPCHExternalASTSource(llvm::StringRef Path,
                                              const std::string &Sysroot,
+                                             bool DisablePCHValidation,
                                              Preprocessor &PP,
                                              ASTContext &Context) {
   llvm::OwningPtr<PCHReader> Reader;
   Reader.reset(new PCHReader(PP, &Context,
-                             Sysroot.empty() ? 0 : Sysroot.c_str()));
+                             Sysroot.empty() ? 0 : Sysroot.c_str(),
+                             DisablePCHValidation));
 
   switch (Reader->ReadPCH(Path)) {
   case PCHReader::Success:
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 68703c22fb4..0ae4739b410 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1353,7 +1353,8 @@ static void ParsePreprocessorArgs(PreprocessorOptions &Opts, ArgList &Args,
     Opts.TokenCache = Opts.ImplicitPTHInclude;
   Opts.UsePredefines = !Args.hasArg(OPT_undef);
   Opts.DetailedRecord = Args.hasArg(OPT_detailed_preprocessing_record);
-  
+  Opts.DisablePCHValidation = Args.hasArg(OPT_fno_validate_pch);
+
   if (const Arg *A = Args.getLastArg(OPT_preamble_bytes_EQ)) {
     llvm::StringRef Value(A->getValue(Args));
     size_t Comma = Value.find(',');
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index dbbf69c8b12..9efa8c61db8 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -118,7 +118,8 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
       assert(hasPCHSupport() && "This action does not have PCH support!");
       CI.createPCHExternalASTSource(
-        CI.getPreprocessorOpts().ImplicitPCHInclude);
+                                CI.getPreprocessorOpts().ImplicitPCHInclude,
+                                CI.getPreprocessorOpts().DisablePCHValidation);
       if (!CI.getASTContext().getExternalSource())
         goto failure;
     }
diff --git a/clang/lib/Frontend/PCHReader.cpp b/clang/lib/Frontend/PCHReader.cpp
index f454477c50a..37e11249f88 100644
--- a/clang/lib/Frontend/PCHReader.cpp
+++ b/clang/lib/Frontend/PCHReader.cpp
@@ -414,13 +414,14 @@ void PCHValidator::ReadCounter(unsigned Value) {
 //===----------------------------------------------------------------------===//
 
 PCHReader::PCHReader(Preprocessor &PP, ASTContext *Context,
-                     const char *isysroot)
+                     const char *isysroot, bool DisableValidation)
   : Listener(new PCHValidator(PP, *this)), DeserializationListener(0),
     SourceMgr(PP.getSourceManager()), FileMgr(PP.getFileManager()),
     Diags(PP.getDiagnostics()), SemaObj(0), PP(&PP), Context(Context),
     Consumer(0), MethodPoolLookupTable(0), MethodPoolLookupTableData(0),
     TotalSelectorsInMethodPool(0), SelectorOffsets(0),
-    TotalNumSelectors(0),  isysroot(isysroot), NumStatHits(0), NumStatMisses(0),
+    TotalNumSelectors(0),  isysroot(isysroot), 
+    DisableValidation(DisableValidation), NumStatHits(0), NumStatMisses(0),
     NumSLocEntriesRead(0), TotalNumSLocEntries(0), NumStatementsRead(0),
     TotalNumStatements(0), NumMacrosRead(0), NumMethodPoolSelectorsRead(0),
     NumMethodPoolMisses(0), TotalNumMacros(0), NumLexicalDeclContextsRead(0),
@@ -430,12 +431,14 @@ PCHReader::PCHReader(Preprocessor &PP, ASTContext *Context,
 }
 
 PCHReader::PCHReader(SourceManager &SourceMgr, FileManager &FileMgr,
-                     Diagnostic &Diags, const char *isysroot)
+                     Diagnostic &Diags, const char *isysroot,
+                     bool DisableValidation)
   : DeserializationListener(0), SourceMgr(SourceMgr), FileMgr(FileMgr),
     Diags(Diags), SemaObj(0), PP(0), Context(0), Consumer(0),
     MethodPoolLookupTable(0), MethodPoolLookupTableData(0),
     TotalSelectorsInMethodPool(0), SelectorOffsets(0),
-    TotalNumSelectors(0), isysroot(isysroot), NumStatHits(0), NumStatMisses(0),
+    TotalNumSelectors(0), isysroot(isysroot), 
+    DisableValidation(DisableValidation), NumStatHits(0), NumStatMisses(0),
     NumSLocEntriesRead(0), TotalNumSLocEntries(0), NumStatementsRead(0),
     TotalNumStatements(0), NumMacrosRead(0), NumMethodPoolSelectorsRead(0),
     NumMethodPoolMisses(0), TotalNumMacros(0), NumLexicalDeclContextsRead(0),
@@ -1019,14 +1022,15 @@ PCHReader::PCHReadResult PCHReader::ReadSLocEntryRecord(unsigned ID) {
       return Failure;
     }
 
-    if ((off_t)Record[4] != File->getSize()
+    if (!DisableValidation &&
+        ((off_t)Record[4] != File->getSize()
 #if !defined(LLVM_ON_WIN32)
         // In our regression testing, the Windows file system seems to
         // have inconsistent modification times that sometimes
         // erroneously trigger this error-handling path.
-        || (time_t)Record[5] != File->getModificationTime()
+         || (time_t)Record[5] != File->getModificationTime()
 #endif
-        ) {
+        )) {
       Diag(diag::err_fe_pch_file_modified)
         << Filename;
       return Failure;
@@ -1481,7 +1485,7 @@ PCHReader::ReadPCHBlock(PerFileData &F) {
       break;
 
     case pch::METADATA: {
-      if (Record[0] != pch::VERSION_MAJOR) {
+      if (Record[0] != pch::VERSION_MAJOR && !DisableValidation) {
         Diag(Record[0] < pch::VERSION_MAJOR? diag::warn_pch_version_too_old
                                            : diag::warn_pch_version_too_new);
         return IgnorePCH;
@@ -1501,7 +1505,7 @@ PCHReader::ReadPCHBlock(PerFileData &F) {
         Error("CHAINED_METADATA is not first record in block");
         return Failure;
       }
-      if (Record[0] != pch::VERSION_MAJOR) {
+      if (Record[0] != pch::VERSION_MAJOR && !DisableValidation) {
         Diag(Record[0] < pch::VERSION_MAJOR? diag::warn_pch_version_too_old
                                            : diag::warn_pch_version_too_new);
         return IgnorePCH;
@@ -1536,7 +1540,7 @@ PCHReader::ReadPCHBlock(PerFileData &F) {
       break;
 
     case pch::LANGUAGE_OPTIONS:
-      if (ParseLanguageOptions(Record))
+      if (ParseLanguageOptions(Record) && !DisableValidation)
         return IgnorePCH;
       break;
 
@@ -1704,7 +1708,7 @@ PCHReader::ReadPCHBlock(PerFileData &F) {
     case pch::VERSION_CONTROL_BRANCH_REVISION: {
       const std::string &CurBranch = getClangFullRepositoryVersion();
       llvm::StringRef PCHBranch(BlobStart, BlobLen);
-      if (llvm::StringRef(CurBranch) != PCHBranch) {
+      if (llvm::StringRef(CurBranch) != PCHBranch && !DisableValidation) {
         Diag(diag::warn_pch_different_branch) << PCHBranch << CurBranch;
         return IgnorePCH;
       }
@@ -1759,7 +1763,7 @@ PCHReader::PCHReadResult PCHReader::ReadPCH(const std::string &FileName) {
   }
 
   // Check the predefines buffers.
-  if (CheckPredefinesBuffers())
+  if (!DisableValidation && CheckPredefinesBuffers())
     return IgnorePCH;
 
   if (PP) {