Eliminate excessive PCH deserialization caused by the search for

__cxxabiv1::__fundamental_type_info in every translation
unit. Previously, we would perform name lookup for
__cxxabiv1::__fundamental_type_info at the end of IRGen for a each
translation unit, to determine whether it was present. If so, we we
produce type information for all of the fundamental types. However,
this name lookup causes PCH deserialization of a significant part of the
translation unit, which has a woeful impact on performance.

With this change, we now look at each record type after we've
generated its vtable to see if it is
__cxxabiv1::__fundamental_type_info. If so, we generate type info for
all of the fundamental types. This works because
__cxxabiv1::__fundamental_type_info should always have a key function
(typically the virtual destructor), that will be defined once in the
support library. The fundamental type information will end up there.

Fixes <rdar://problem/7840011>.

llvm-svn: 100772

1 files changed, 3 insertions, 1 deletions

diff --git a/clang/test/CodeGenCXX/rtti-fundamental.cpp b/clang/test/CodeGenCXX/rtti-fundamental.cpp
index 473f48db67a..6826321cd5e 100644
--- a/clang/test/CodeGenCXX/rtti-fundamental.cpp
+++ b/clang/test/CodeGenCXX/rtti-fundamental.cpp
@@ -8,8 +8,10 @@ std::type_info foo() {
 
 namespace __cxxabiv1 {
   struct __fundamental_type_info {
-    virtual ~__fundamental_type_info() {}
+    virtual ~__fundamental_type_info();
   };
+
+  __fundamental_type_info::~__fundamental_type_info() { }
 }
 
 // CHECK: @_ZTIv = weak_odr constant