Revamp the SourceManager to separate the representation of parsed

source locations from source locations loaded from an AST/PCH file.

Previously, loading an AST/PCH file involved carefully pre-allocating
space at the beginning of the source manager for the source locations
and FileIDs that correspond to the prefix, and then appending the
source locations/FileIDs used for parsing the remaining translation
unit. This design forced us into loading PCH files early, as a prefix,
whic has become a rather significant limitation.

This patch splits the SourceManager space into two parts: for source
location "addresses", the lower values (growing upward) are used to
describe parsed code, while upper values (growing downward) are used
for source locations loaded from AST/PCH files. Similarly, positive
FileIDs are used to describe parsed code while negative FileIDs are
used to file/macro locations loaded from AST/PCH files. As a result,
we can load PCH/AST files even during parsing, making various
improvemnts in the future possible, e.g., teaching #include <foo.h> to
look for and load <foo.h.gch> if it happens to be already available.

This patch was originally written by Sebastian Redl, then brought
forward to the modern age by Jonathan Turner, and finally
polished/finished by me to be committed.




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135484 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 2 deletions

diff --git a/include/clang/Frontend/CompilerInstance.h b/include/clang/Frontend/CompilerInstance.h
index 004c8896e2..b2c877ac40 100644
--- a/include/clang/Frontend/CompilerInstance.h
+++ b/include/clang/Frontend/CompilerInstance.h
@@ -27,13 +27,13 @@ class Timer;
 namespace clang {
 class ASTContext;
 class ASTConsumer;
+class ASTReader;
 class CodeCompleteConsumer;
 class Diagnostic;
 class DiagnosticClient;
 class ExternalASTSource;
 class FileManager;
 class FrontendAction;
-class ASTReader;
 class Preprocessor;
 class Sema;
 class SourceManager;
@@ -88,9 +88,12 @@ class CompilerInstance {
   /// \brief The semantic analysis object.
   llvm::OwningPtr<Sema> TheSema;
   
-  /// The frontend timer
+  /// \brief The frontend timer
   llvm::OwningPtr<llvm::Timer> FrontendTimer;
 
+  /// \brief Non-owning reference to the ASTReader, if one exists.
+  ASTReader *ModuleManager;
+
   /// \brief Holds information about the output file.
   ///
   /// If TempFilename is not empty we must rename it to Filename at the end.
@@ -388,6 +391,12 @@ public:
   Sema *takeSema() { return TheSema.take(); }
   
   /// }
+  /// @name Module Management
+  /// {
+
+  ASTReader *getModuleManager() const { return ModuleManager; }
+
+  /// }
   /// @name Code Completion
   /// {