r205651 - DebugInfo: PR19298: function local const variables duplicated in the root scope

[David Blaikie]

Author: dblaikie
Date: Fri Apr  4 15:56:17 2014
New Revision: 205651

URL: http://llvm.org/viewvc/llvm-project?rev=205651&view=rev
Log:
DebugInfo: PR19298: function local const variables duplicated in the root scope

See the comment for CodeGenFunction::tryEmitAsConstant that describes
how in some contexts (lambdas) we must not emit references to the
variable, but instead use the constant directly - because of this we end
up emitting a constant for the variable, as well as emitting the
variable itself.

Should we just skip putting the variable on the stack at all and omit
the debug info for the constant? It's not clear to me - what if the
address of the local is taken?

Modified:
    cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
    cfe/trunk/test/CodeGenCXX/debug-info.cpp

Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.cpp?rev=205651&r1=205650&r2=205651&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp Fri Apr  4 15:56:17 2014
@@ -3227,6 +3227,9 @@ void CGDebugInfo::EmitGlobalVariable(con
   // Do not use DIGlobalVariable for enums.
   if (Ty.getTag() == llvm::dwarf::DW_TAG_enumeration_type)
     return;
+  // Do not emit separate definitions for function local const/statics.
+  if (isa<FunctionDecl>(VD->getDeclContext()))
+    return;
   llvm::DIGlobalVariable GV = DBuilder.createStaticVariable(
       Unit, Name, Name, Unit, getLineNumber(VD->getLocation()), Ty, true, Init,
       getOrCreateStaticDataMemberDeclarationOrNull(cast<VarDecl>(VD)));

Modified: cfe/trunk/test/CodeGenCXX/debug-info.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/debug-info.cpp?rev=205651&r1=205650&r2=205651&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/debug-info.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/debug-info.cpp Fri Apr  4 15:56:17 2014
@@ -51,11 +51,6 @@ namespace VirtualBase {
   }
 }
 
-void foo() {
-  const wchar_t c = L'x';
-  wchar_t d = c;
-}
-
 namespace b5249287 {
 template <typename T> class A {
   struct B;
@@ -88,6 +83,13 @@ foo func(foo f) {
 // CHECK: [[FUNC:![0-9]*]] = {{.*}} metadata !"_ZN7pr147634funcENS_3fooE", i32 {{[0-9]*}}, metadata [[FUNC_TYPE:![0-9]*]], {{.*}} ; [ DW_TAG_subprogram ] {{.*}} [def] [func]
 }
 
+void foo() {
+  const wchar_t c = L'x';
+  wchar_t d = c;
+}
+
+// CHECK-NOT: ; [ DW_TAG_variable ] [c]
+
 namespace pr9608 { // also pr9600
 struct incomplete;
 incomplete (*x)[3];
@@ -96,9 +98,11 @@ incomplete (*x)[3];
 // CHECK: [[INCARRAY]] = {{.*}}metadata !"_ZTSN6pr960810incompleteE", metadata {{![0-9]*}}, i32 0, null, null, null} ; [ DW_TAG_array_type ] [line 0, size 0, align 0, offset 0] [from _ZTSN6pr960810incompleteE]
 }
 
-// For some reason the argument for PR14763 ended up all the way down here
+// For some reason function arguments ended up down here
 // CHECK: = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], {{.*}}, metadata !"[[FOO]]", i32 8192, i32 0} ; [ DW_TAG_arg_variable ] [f]
 
+// CHECK: ; [ DW_TAG_auto_variable ] [c]
+
 namespace pr16214 {
 struct a {
   int i;