Replace Sema's map of locally-scoped extern "C" declarations with a DeclContext

of extern "C" declarations. This is simpler and vastly more efficient for
modules builds (we no longer need to load *all* extern "C" declarations to
determine if we have a redeclaration).

No functionality change intended.

llvm-svn: 231538

1 files changed, 9 insertions, 1 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 9cfc97b926d..20d2aa68187 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -738,7 +738,8 @@ ASTContext::ASTContext(LangOptions &LOpts, SourceManager &SM,
       FILEDecl(nullptr), jmp_bufDecl(nullptr), sigjmp_bufDecl(nullptr),
       ucontext_tDecl(nullptr), BlockDescriptorType(nullptr),
       BlockDescriptorExtendedType(nullptr), cudaConfigureCallDecl(nullptr),
-      FirstLocalImport(), LastLocalImport(), SourceMgr(SM), LangOpts(LOpts),
+      FirstLocalImport(), LastLocalImport(), ExternCContext(nullptr),
+      SourceMgr(SM), LangOpts(LOpts),
       SanitizerBL(new SanitizerBlacklist(LangOpts.SanitizerBlacklistFiles, SM)),
       AddrSpaceMap(nullptr), Target(nullptr), PrintingPolicy(LOpts),
       Idents(idents), Selectors(sels), BuiltinInfo(builtins),
@@ -865,6 +866,13 @@ void ASTContext::PrintStats() const {
   BumpAlloc.PrintStats();
 }
 
+ExternCContextDecl *ASTContext::getExternCContextDecl() const {
+  if (!ExternCContext)
+    ExternCContext = ExternCContextDecl::Create(*this, getTranslationUnitDecl());
+
+  return ExternCContext;
+}
+
 RecordDecl *ASTContext::buildImplicitRecord(StringRef Name,
                                             RecordDecl::TagKind TK) const {
   SourceLocation Loc;