Allow resolving headers from a PCH even after headers+PCH were moved to another path.

Store in PCH the directory that the PCH was originally created in.
If a header file is not found at the path that we expect it to be and the PCH file
was moved from its original location, try to resolve the file by assuming that
header+PCH were moved together and the header is in the same place relative to the PCH.

llvm-svn: 125576

2 files changed, 10 insertions, 5 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 00902e810c2..0370c2e125b 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -653,7 +653,7 @@ public:
   PrecompilePreambleConsumer(ASTUnit &Unit,
                              const Preprocessor &PP, bool Chaining,
                              const char *isysroot, llvm::raw_ostream *Out)
-    : PCHGenerator(PP, Chaining, isysroot, Out), Unit(Unit) { }
+    : PCHGenerator(PP, "", Chaining, isysroot, Out), Unit(Unit) { }
 
   virtual void HandleTopLevelDecl(DeclGroupRef D) {
     for (DeclGroupRef::iterator it = D.begin(), ie = D.end(); it != ie; ++it) {
@@ -700,9 +700,11 @@ public:
   virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
                                          llvm::StringRef InFile) {
     std::string Sysroot;
+    std::string OutputFile;
     llvm::raw_ostream *OS = 0;
     bool Chaining;
-    if (GeneratePCHAction::ComputeASTConsumerArguments(CI, InFile, Sysroot, 
+    if (GeneratePCHAction::ComputeASTConsumerArguments(CI, InFile, Sysroot,
+                                                       OutputFile,
                                                        OS, Chaining))
       return 0;
     
@@ -2008,7 +2010,7 @@ bool ASTUnit::Save(llvm::StringRef File) {
   std::vector<unsigned char> Buffer;
   llvm::BitstreamWriter Stream(Buffer);
   ASTWriter Writer(Stream);
-  Writer.WriteAST(getSema(), 0, 0);
+  Writer.WriteAST(getSema(), 0, std::string(), 0);
   
   // Write the generated bitstream to "Out".
   if (!Buffer.empty())
diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index 0ffea201cd4..e454321c0cc 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -83,19 +83,21 @@ ASTConsumer *DeclContextPrintAction::CreateASTConsumer(CompilerInstance &CI,
 ASTConsumer *GeneratePCHAction::CreateASTConsumer(CompilerInstance &CI,
                                                   llvm::StringRef InFile) {
   std::string Sysroot;
+  std::string OutputFile;
   llvm::raw_ostream *OS = 0;
   bool Chaining;
-  if (ComputeASTConsumerArguments(CI, InFile, Sysroot, OS, Chaining))
+  if (ComputeASTConsumerArguments(CI, InFile, Sysroot, OutputFile, OS, Chaining))
     return 0;
 
   const char *isysroot = CI.getFrontendOpts().RelocatablePCH ?
                              Sysroot.c_str() : 0;  
-  return new PCHGenerator(CI.getPreprocessor(), Chaining, isysroot, OS);
+  return new PCHGenerator(CI.getPreprocessor(), OutputFile, Chaining, isysroot, OS);
 }
 
 bool GeneratePCHAction::ComputeASTConsumerArguments(CompilerInstance &CI,
                                                     llvm::StringRef InFile,
                                                     std::string &Sysroot,
+                                                    std::string &OutputFile,
                                                     llvm::raw_ostream *&OS,
                                                     bool &Chaining) {
   Sysroot = CI.getHeaderSearchOpts().Sysroot;
@@ -111,6 +113,7 @@ bool GeneratePCHAction::ComputeASTConsumerArguments(CompilerInstance &CI,
   if (!OS)
     return true;
 
+  OutputFile = CI.getFrontendOpts().OutputFile;
   Chaining = CI.getInvocation().getFrontendOpts().ChainedPCH &&
              !CI.getPreprocessorOpts().ImplicitPCHInclude.empty();
   return false;