From: David Blaikie <dblaikie@gmail.com>
Date: Thu, 1 Aug 2013 20:57:40 +0000 (+0000)
Subject: DebugInfo: Don't prefer declarations over definitions in -flimit-debug-info in C
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=79af384d72355dca4174e5a9ee391d38226896bc;p=platform%2Fupstream%2Fllvm.git

DebugInfo: Don't prefer declarations over definitions in -flimit-debug-info in C

Without an ODR, the -flimit-debug-info debug info size optimization of
emitting declarations for fully defined types when only a declaration is
needed by the TU, is incorrect. Emit the full definition whenever it's
available in non-C++.

llvm-svn: 187611
---

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 0e3b98d..c903a2c 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1422,7 +1422,7 @@ llvm::DIType CGDebugInfo::CreateType(const RecordType *Ty, bool Declaration) {
   // Limited debug info should only remove struct definitions that can
   // safely be replaced by a forward declaration in the source code.
   if (DebugKind <= CodeGenOptions::LimitedDebugInfo && Declaration &&
-      !RD->isCompleteDefinitionRequired()) {
+      !RD->isCompleteDefinitionRequired() && CGM.getLangOpts().CPlusPlus) {
     // FIXME: This implementation is problematic; there are some test
     // cases where we violate the above principle, such as
     // test/CodeGen/debug-info-records.c .
@@ -1951,7 +1951,8 @@ llvm::DIType CGDebugInfo::getCompletedTypeOrNull(QualType Ty) {
 void CGDebugInfo::completeFwdDecl(const RecordDecl &RD) {
   // In limited debug info we only want to do this if the complete type was
   // required.
-  if (DebugKind <= CodeGenOptions::LimitedDebugInfo)
+  if (DebugKind <= CodeGenOptions::LimitedDebugInfo &&
+      CGM.getLangOpts().CPlusPlus)
     return;
 
   QualType QTy = CGM.getContext().getRecordType(&RD);
diff --git a/clang/test/CodeGen/debug-info-limited.c b/clang/test/CodeGen/debug-info-limited.c
new file mode 100644
index 0000000..7333452
--- /dev/null
+++ b/clang/test/CodeGen/debug-info-limited.c
@@ -0,0 +1,11 @@
+// RUN: %clang -flimit-debug-info -emit-llvm -g -S %s -o - | FileCheck %s
+
+// Ensure we emit the full definition of 'foo' even though only its declaration
+// is needed, since C has no ODR to ensure that the definition will be the same
+// in whatever TU actually uses/requires the definition of 'foo'.
+// CHECK: ; [ DW_TAG_structure_type ] [foo] {{.*}} [def]
+
+struct foo {
+};
+
+struct foo *f;
diff --git a/clang/test/CodeGenCXX/debug-info-limited.cpp b/clang/test/CodeGenCXX/debug-info-limited.cpp
index f15dce5..12c9c04 100644
--- a/clang/test/CodeGenCXX/debug-info-limited.cpp
+++ b/clang/test/CodeGenCXX/debug-info-limited.cpp
@@ -1,7 +1,6 @@
-// RUN: %clang  -emit-llvm -g -S %s -o - | FileCheck %s
+// RUN: %clang -flimit-debug-info -emit-llvm -g -S %s -o - | FileCheck %s
 
-// TAG_member is used to encode debug info for 'z' in A.
-// CHECK: TAG_member
+// CHECK: ; [ DW_TAG_class_type ] [A] {{.*}} [def]
 class A {
 public:
   int z;
@@ -13,8 +12,7 @@ A *foo (A* x) {
 }
 
 // Verify that we're not emitting a full definition of B in limit debug mode.
-// RUN: %clang -emit-llvm -g -flimit-debug-info -S %s -o - | FileCheck %s
-// CHECK-NOT: TAG_member
+// CHECK: ; [ DW_TAG_class_type ] [B] {{.*}} [decl]
 
 class B {
 public: