Introduce a fast path for the ASTReader's name lookup within a
DeclContext. When the DeclContext is of a kind that can only be
defined once and never updated, we limit the search to the module file
that conatins the lookup table. Provides a 15% speedup in one
modules-heavy source file.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173050 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/ASTCommon.cpp b/lib/Serialization/ASTCommon.cpp
index bf1e25a..df87165 100644
--- a/lib/Serialization/ASTCommon.cpp
+++ b/lib/Serialization/ASTCommon.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "ASTCommon.h"
+#include "clang/AST/DeclObjC.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Serialization/ASTDeserializationListener.h"
#include "llvm/ADT/StringExtras.h"
@@ -85,3 +86,60 @@
R = llvm::HashString(II->getName(), R);
return R;
}
+
+const Decl *serialization::getDefinitiveDeclContext(const DeclContext *DC) {
+ switch (DC->getDeclKind()) {
+ // These entities may have multiple definitions.
+ case Decl::TranslationUnit:
+ case Decl::Namespace:
+ case Decl::LinkageSpec:
+ return 0;
+
+ // C/C++ tag types can only be defined in one place.
+ case Decl::Enum:
+ case Decl::Record:
+ if (const TagDecl *Def = cast<TagDecl>(DC)->getDefinition())
+ return Def;
+ break;
+
+ // FIXME: These can be defined in one place... except special member
+ // functions and out-of-line definitions.
+ case Decl::CXXRecord:
+ case Decl::ClassTemplateSpecialization:
+ case Decl::ClassTemplatePartialSpecialization:
+ return 0;
+
+ // Each function, method, and block declaration is its own DeclContext.
+ case Decl::Function:
+ case Decl::CXXMethod:
+ case Decl::CXXConstructor:
+ case Decl::CXXDestructor:
+ case Decl::CXXConversion:
+ case Decl::ObjCMethod:
+ case Decl::Block:
+ // Objective C categories, category implementations, and class
+ // implementations can only be defined in one place.
+ case Decl::ObjCCategory:
+ case Decl::ObjCCategoryImpl:
+ case Decl::ObjCImplementation:
+ return cast<Decl>(DC);
+
+ case Decl::ObjCProtocol:
+ if (const ObjCProtocolDecl *Def
+ = cast<ObjCProtocolDecl>(DC)->getDefinition())
+ return Def;
+ break;
+
+ // FIXME: These are defined in one place, but properties in class extensions
+ // end up being back-patched into the main interface. See
+ // Sema::HandlePropertyInClassExtension for the offending code.
+ case Decl::ObjCInterface:
+ break;
+
+ default:
+ llvm_unreachable("Unhandled DeclContext in AST reader");
+ }
+
+ return 0;
+
+}