Introduce the ASTUnit class.
ASTUnit is a helper class to allow easy loading of an ASTContext from a PCH file. No users for now.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@73819 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
new file mode 100644
index 0000000..6ed8fbd
--- /dev/null
+++ b/lib/Frontend/ASTUnit.cpp
@@ -0,0 +1,146 @@
+#include "clang/Frontend/ASTUnit.h"
+#include "clang/Frontend/PCHReader.h"
+#include "clang/Frontend/TextDiagnosticBuffer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclVisitor.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/Basic/Diagnostic.h"
+#include "llvm/Support/Compiler.h"
+
+using namespace clang;
+
+ASTUnit::ASTUnit() { }
+ASTUnit::~ASTUnit() { }
+
+namespace {
+
+/// \brief Gathers information from PCHReader that will be used to initialize
+/// a Preprocessor.
+class VISIBILITY_HIDDEN PCHInfoCollector : public PCHReaderListener {
+ LangOptions &LangOpt;
+ HeaderSearch &HSI;
+ std::string &TargetTriple;
+ std::string &Predefines;
+ unsigned &Counter;
+
+ unsigned NumHeaderInfos;
+
+public:
+ PCHInfoCollector(LangOptions &LangOpt, HeaderSearch &HSI,
+ std::string &TargetTriple, std::string &Predefines,
+ unsigned &Counter)
+ : LangOpt(LangOpt), HSI(HSI), TargetTriple(TargetTriple),
+ Predefines(Predefines), Counter(Counter), NumHeaderInfos(0) {}
+
+ virtual bool ReadLanguageOptions(const LangOptions &LangOpts) {
+ LangOpt = LangOpts;
+ return false;
+ }
+
+ virtual bool ReadTargetTriple(const std::string &Triple) {
+ TargetTriple = Triple;
+ return false;
+ }
+
+ virtual bool ReadPredefinesBuffer(const char *PCHPredef,
+ unsigned PCHPredefLen,
+ FileID PCHBufferID,
+ std::string &SuggestedPredefines) {
+ Predefines = PCHPredef;
+ return false;
+ }
+
+ virtual void ReadHeaderFileInfo(const HeaderFileInfo &HFI) {
+ HSI.setHeaderFileInfoForUID(HFI, NumHeaderInfos++);
+ }
+
+ virtual void ReadCounter(unsigned Value) {
+ Counter = Value;
+ }
+};
+
+} // anonymous namespace
+
+
+ASTUnit *ASTUnit::LoadFromPCHFile(const std::string &Filename,
+ FileManager &FileMgr,
+ std::string *ErrMsg) {
+
+ llvm::OwningPtr<ASTUnit> AST(new ASTUnit());
+
+ AST->DiagClient.reset(new TextDiagnosticBuffer());
+ AST->Diags.reset(new Diagnostic(AST->DiagClient.get()));
+
+ AST->HeaderInfo.reset(new HeaderSearch(FileMgr));
+ AST->SourceMgr.reset(new SourceManager());
+
+ Diagnostic &Diags = *AST->Diags.get();
+ SourceManager &SourceMgr = *AST->SourceMgr.get();
+
+ // Gather Info for preprocessor construction later on.
+
+ LangOptions LangInfo;
+ HeaderSearch &HeaderInfo = *AST->HeaderInfo.get();
+ std::string TargetTriple;
+ std::string Predefines;
+ unsigned Counter;
+
+ llvm::OwningPtr<PCHReader> Reader;
+ llvm::OwningPtr<ExternalASTSource> Source;
+
+ Reader.reset(new PCHReader(SourceMgr, FileMgr, Diags));
+ Reader->setListener(new PCHInfoCollector(LangInfo, HeaderInfo, TargetTriple,
+ Predefines, Counter));
+
+ switch (Reader->ReadPCH(Filename)) {
+ case PCHReader::Success:
+ break;
+
+ case PCHReader::Failure:
+ // Unrecoverable failure: don't even try to process the input
+ // file.
+ if (ErrMsg)
+ *ErrMsg = "Could not load PCH file";
+ return NULL;
+
+ case PCHReader::IgnorePCH:
+ assert(0 && "Is there a validation that should not have happened ?");
+ }
+
+ // PCH loaded successfully. Now create the preprocessor.
+
+ // Get information about the target being compiled for.
+ AST->Target.reset(TargetInfo::CreateTargetInfo(TargetTriple));
+ AST->PP.reset(new Preprocessor(Diags, LangInfo, *AST->Target.get(),
+ SourceMgr, HeaderInfo));
+ Preprocessor &PP = *AST->PP.get();
+
+ PP.setPredefines(Predefines);
+ PP.setCounterValue(Counter);
+ Reader->setPreprocessor(PP);
+
+ // Create and initialize the ASTContext.
+
+ AST->Ctx.reset(new ASTContext(LangInfo,
+ SourceMgr,
+ *AST->Target.get(),
+ PP.getIdentifierTable(),
+ PP.getSelectorTable(),
+ PP.getBuiltinInfo(),
+ /* FreeMemory = */ true,
+ /* size_reserve = */0));
+ ASTContext &Context = *AST->Ctx.get();
+
+ Reader->InitializeContext(Context);
+
+ // Attach the PCH reader to the AST context as an external AST
+ // source, so that declarations will be deserialized from the
+ // PCH file as needed.
+ Source.reset(Reader.take());
+ Context.setExternalSource(Source);
+
+ return AST.take();
+}