r274246 - [codeview] Emit qualified display names if -gline-tables-only is on

[Reid Kleckner via cfe-commits]

Author: rnk
Date: Thu Jun 30 12:41:31 2016
New Revision: 274246

URL: http://llvm.org/viewvc/llvm-project?rev=274246&view=rev
Log:
[codeview] Emit qualified display names if -gline-tables-only is on

When -gmlt is on, we don't emit namespace or class scope information,
and the CodeView emission code in LLVM can't compute the fully qualified
name. If we know LLVM won't be able to get the name right, go ahead and
emit the qualified name in the frontend.

We could change our -gmlt emission strategy to include those scopes when
emitting codeview, but that would increase memory usage and slow down
LTO and add more complexity to debug info emission.

The same problem exists when you debug a -gmlt binary with GDB, so we
should consider removing '&& EmitCodeView' from the condition here at
some point in the future after evaluating the impact on object file
size.

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

Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.cpp?rev=274246&r1=274245&r2=274246&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp Thu Jun 30 12:41:31 2016
@@ -185,17 +185,27 @@ StringRef CGDebugInfo::getFunctionName(c
   FunctionTemplateSpecializationInfo *Info =
       FD->getTemplateSpecializationInfo();
 
-  if (!Info && FII)
+  // Emit the unqualified name in normal operation. LLVM and the debugger can
+  // compute the fully qualified name from the scope chain. If we're only
+  // emitting line table info, there won't be any scope chains, so emit the
+  // fully qualified name here so that stack traces are more accurate.
+  // FIXME: Do this when emitting DWARF as well as when emitting CodeView after
+  // evaluating the size impact.
+  bool UseQualifiedName = DebugKind == codegenoptions::DebugLineTablesOnly &&
+                          CGM.getCodeGenOpts().EmitCodeView;
+
+  if (!Info && FII && !UseQualifiedName)
     return FII->getName();
 
-  // Otherwise construct human readable name for debug info.
   SmallString<128> NS;
   llvm::raw_svector_ostream OS(NS);
   PrintingPolicy Policy(CGM.getLangOpts());
   Policy.MSVCFormatting = CGM.getCodeGenOpts().EmitCodeView;
+  if (!UseQualifiedName)
+    FD->printName(OS);
+  else
+    FD->printQualifiedName(OS, Policy);
 
-  // Print the unqualified name with some template arguments.
-  FD->printName(OS);
   // Add any template specialization args.
   if (Info) {
     const TemplateArgumentList *TArgs = Info->TemplateArguments;

Modified: cfe/trunk/test/CodeGenCXX/debug-info-codeview-display-name.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/debug-info-codeview-display-name.cpp?rev=274246&r1=274245&r2=274246&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/debug-info-codeview-display-name.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/debug-info-codeview-display-name.cpp Thu Jun 30 12:41:31 2016
@@ -1,14 +1,22 @@
-// RUN: %clang_cc1 -fblocks -debug-info-kind=limited -gcodeview -emit-llvm %s -o - -triple=x86_64-pc-win32 -std=c++98 | \
-// RUN:  grep 'DISubprogram' | sed -e 's/.*name: "\([^"]*\)".*/"\1"/' | FileCheck %s
+// RUN: %clang_cc1 -fblocks -debug-info-kind=limited -gcodeview -emit-llvm %s \
+// RUN:       -o - -triple=x86_64-pc-win32 -std=c++98 | \
+// RUN:    grep 'DISubprogram' | sed -e 's/.*name: "\([^"]*\)".*/"\1"/' | \
+// RUN:    FileCheck %s --check-prefix=CHECK --check-prefix=UNQUAL
+// RUN: %clang_cc1 -fblocks -debug-info-kind=line-tables-only -gcodeview -emit-llvm %s \
+// RUN:       -o - -triple=x86_64-pc-win32 -std=c++98 | \
+// RUN:    grep 'DISubprogram' | sed -e 's/.*name: "\([^"]*\)".*/"\1"/' | \
+// RUN:    FileCheck %s --check-prefix=CHECK --check-prefix=QUAL
 
 void freefunc() { }
 // CHECK-DAG: "freefunc"
 
 namespace N {
   int b() { return 0; }
-// CHECK-DAG: "b"
+// UNQUAL-DAG: "b"
+// QUAL-DAG: "N::b"
   namespace { void func() { } }
-// CHECK-DAG: "func"
+// UNQUAL-DAG: "func"
+// QUAL-DAG: "N::`anonymous namespace'::func"
 }
 
 void _c(void) {
@@ -19,19 +27,24 @@ void _c(void) {
 struct foo {
   int operator+(int);
   foo(){}
-// CHECK-DAG: "foo"
+// UNQUAL-DAG: "foo"
+// QUAL-DAG: "foo::foo"
 
   ~foo(){}
-// CHECK-DAG: "~foo"
+// UNQUAL-DAG: "~foo"
+// QUAL-DAG: "foo::~foo"
 
   foo(int i){}
-// CHECK-DAG: "foo"
+// UNQUAL-DAG: "foo"
+// QUAL-DAG: "foo::foo"
 
   foo(char *q){}
-// CHECK-DAG: "foo"
+// UNQUAL-DAG: "foo"
+// QUAL-DAG: "foo::foo"
 
   static foo* static_method() { return 0; }
-// CHECK-DAG: "static_method"
+// UNQUAL-DAG: "static_method"
+// QUAL-DAG: "foo::static_method"
 
 };
 
@@ -40,7 +53,8 @@ void use_foo() {
   foo::static_method();
 }
 
-// CHECK-DAG: "operator+"
+// UNQUAL-DAG: "operator+"
+// QUAL-DAG: "foo::operator+"
 int foo::operator+(int a) { return a; }
 
 // PR17371
@@ -60,11 +74,17 @@ void OverloadedNewDelete::operator delet
 void OverloadedNewDelete::operator delete[](void *) { }
 int OverloadedNewDelete::operator+(int x) { return x; };
 
-// CHECK-DAG: "operator new"
-// CHECK-DAG: "operator new[]"
-// CHECK-DAG: "operator delete"
-// CHECK-DAG: "operator delete[]"
-// CHECK-DAG: "operator+"
+// UNQUAL-DAG: "operator new"
+// UNQUAL-DAG: "operator new[]"
+// UNQUAL-DAG: "operator delete"
+// UNQUAL-DAG: "operator delete[]"
+// UNQUAL-DAG: "operator+"
+// QUAL-DAG: "OverloadedNewDelete::operator new"
+// QUAL-DAG: "OverloadedNewDelete::operator new[]"
+// QUAL-DAG: "OverloadedNewDelete::operator delete"
+// QUAL-DAG: "OverloadedNewDelete::operator delete[]"
+// QUAL-DAG: "OverloadedNewDelete::operator+"
+
 
 template <typename T, void (*)(void)>
 void fn_tmpl() {}