Add caching when looking up coroutine_traits

Summary:
Currently clang looks up the coroutine_traits ClassTemplateDecl
everytime it looks up the promise type. This is unnecessary
as coroutine_traits doesn't change between promise type lookups.

This diff caches the coroutine_traits lookup.

Patch by Tanoy Sinha!

Test Plan:
I added log statements in the new lookupCoroutineTraits function
to ensure that LookupQualifiedName was only called once even
when multiple coroutines existed in the source file.

Reviewers: modocache, GorNishanov

Reviewed By: modocache

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D48981

llvm-svn: 337103

1 files changed, 3 insertions, 3 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index b26cf3c0432..55000e3e350 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -131,9 +131,9 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
       IsBuildingRecoveryCallExpr(false), Cleanup{}, LateTemplateParser(nullptr),
       LateTemplateParserCleanup(nullptr), OpaqueParser(nullptr), IdResolver(pp),
       StdExperimentalNamespaceCache(nullptr), StdInitializerList(nullptr),
-      CXXTypeInfoDecl(nullptr), MSVCGuidDecl(nullptr), NSNumberDecl(nullptr),
-      NSValueDecl(nullptr), NSStringDecl(nullptr),
-      StringWithUTF8StringMethod(nullptr),
+      StdCoroutineTraitsCache(nullptr), CXXTypeInfoDecl(nullptr),
+      MSVCGuidDecl(nullptr), NSNumberDecl(nullptr), NSValueDecl(nullptr),
+      NSStringDecl(nullptr), StringWithUTF8StringMethod(nullptr),
       ValueWithBytesObjCTypeMethod(nullptr), NSArrayDecl(nullptr),
       ArrayWithObjectsMethod(nullptr), NSDictionaryDecl(nullptr),
       DictionaryWithObjectsMethod(nullptr), GlobalNewDeleteDeclared(false),