From d27858932960f74bf05223bf63d398f1143a8830 Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Sun, 18 Aug 2013 17:36:19 +0000
Subject: [PATCH] DebugInfo: Avoid duplicating types that may be created during
 the process of creating their context

A partner to r188639, this is a somewhat heavy-handed fix to the general
issue, since even after that prior change the issue does still
unavoidably arise with template parameters (see test case).

There are other ways we could consider addressing this (see FIXME).

llvm-svn: 188640
---
 clang/lib/CodeGen/CGDebugInfo.cpp                  | 13 ++++++++++
 .../test/CodeGenCXX/debug-info-template-member.cpp | 28 ++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 3142283..7ffaf7d 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2183,6 +2183,19 @@ llvm::DIType CGDebugInfo::CreateLimitedType(const RecordType *Ty) {
   else
     RDContext = getContextDescriptor(cast<Decl>(RD->getDeclContext()));
 
+  // If we ended up creating the type during the context chain construction,
+  // just return that.
+  // FIXME: this could be dealt with better if the type was recorded as
+  // completed before we started this (see the CompletedTypeCache usage in
+  // CGDebugInfo::CreateTypeDefinition(const RecordType*) - that would need to
+  // be pushed to before context creation, but after it was known to be
+  // destined for completion (might still have an issue if this caller only
+  // required a declaration but the context construction ended up creating a
+  // definition)
+  if (llvm::DIType T = getTypeOrNull(CGM.getContext().getRecordType(RD)))
+    if (!T.isForwardDecl() || !RD->getDefinition())
+      return T;
+
   // If this is just a forward declaration, construct an appropriately
   // marked node and just return it.
   if (!RD->getDefinition())
diff --git a/clang/test/CodeGenCXX/debug-info-template-member.cpp b/clang/test/CodeGenCXX/debug-info-template-member.cpp
index 2354a1a..0e702ac 100644
--- a/clang/test/CodeGenCXX/debug-info-template-member.cpp
+++ b/clang/test/CodeGenCXX/debug-info-template-member.cpp
@@ -17,3 +17,31 @@ inline int add3(int x) {
 // CHECK: metadata [[C_MEM:![0-9]*]], i32 0, null, null} ; [ DW_TAG_structure_type ] [MyClass]
 // CHECK: [[C_MEM]] = metadata !{metadata [[C_TEMP:![0-9]*]]}
 // CHECK: [[C_TEMP]] = {{.*}} ; [ DW_TAG_subprogram ] [line 4] [add<2>]
+
+template<typename T>
+struct outer {
+  struct inner {
+    int i;
+  };
+};
+
+struct foo {
+  void func(outer<foo>::inner);
+};
+
+inline void func() {
+  // require 'foo' to be complete before the emission of 'inner' so that, when
+  // constructing the context chain for 'x' we emit the full definition of
+  // 'foo', which requires the definition of 'inner' again
+  foo f;
+}
+
+outer<foo>::inner x;
+
+// CHECK: metadata [[OUTER_FOO_INNER:![0-9]*]], i32 {{[0-9]*}}, i32 {{[0-9]*}}, %"struct.outer<foo>::inner"* @x, {{.*}} ; [ DW_TAG_variable ] [x]
+// CHECK: [[OUTER_FOO_INNER]] = {{.*}} ; [ DW_TAG_structure_type ] [inner]
+// CHECK: [[FOO_MEM:![0-9]*]], i32 0, null, null} ; [ DW_TAG_structure_type ] [foo]
+// CHECK: [[FOO_MEM]] = metadata !{metadata [[FOO_FUNC:![0-9]*]]}
+// CHECK: [[FOO_FUNC]] = {{.*}}, metadata !"_ZN3foo4funcEN5outerIS_E5innerE", i32 {{[0-9]*}}, metadata [[FOO_FUNC_TYPE:![0-9]*]], {{.*}} ; [ DW_TAG_subprogram ] {{.*}} [func]
+// CHECK: [[FOO_FUNC_TYPE]] = {{.*}}, metadata [[FOO_FUNC_PARAMS:![0-9]*]], i32 0, i32 0} ; [ DW_TAG_subroutine_type ]
+// CHECK: [[FOO_FUNC_PARAMS]] = metadata !{null, metadata !{{[0-9]*}}, metadata [[OUTER_FOO_INNER]]}
-- 
2.7.4