From 906cfe1bf36df2d0efbea663dcc91f9e36e2e097 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Fri, 20 Jul 2018 20:55:00 +0000
Subject: [PATCH] [codeview] Don't emit variable templates as class members

MSVC doesn't, so neither should we.

Fixes PR38004, which is a crash that happens when we try to emit debug
info for a still-dependent partial variable template specialization.

As a follow-up, we should review what we're doing for function and class
member templates. It looks like we don't filter those out, but I can't
seem to get clang to emit any.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@337616 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGDebugInfo.cpp                   | 15 +++++---
 .../debug-info-codeview-var-templates.cpp     | 35 +++++++++++++++++++
 2 files changed, 45 insertions(+), 5 deletions(-)
 create mode 100644 test/CodeGenCXX/debug-info-codeview-var-templates.cpp

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 08447f895e..10fc22a098 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -1298,10 +1298,6 @@ void CGDebugInfo::CollectRecordFields(
   else {
     const ASTRecordLayout &layout = CGM.getContext().getASTRecordLayout(record);
 
-    // Debug info for nested types is included in the member list only for
-    // CodeView.
-    bool IncludeNestedTypes = CGM.getCodeGenOpts().EmitCodeView;
-
     // Field number for non-static fields.
     unsigned fieldNo = 0;
 
@@ -1311,6 +1307,13 @@ void CGDebugInfo::CollectRecordFields(
       if (const auto *V = dyn_cast<VarDecl>(I)) {
         if (V->hasAttr<NoDebugAttr>())
           continue;
+
+        // Skip variable template specializations when emitting CodeView. MSVC
+        // doesn't emit them.
+        if (CGM.getCodeGenOpts().EmitCodeView &&
+            isa<VarTemplateSpecializationDecl>(V))
+          continue;
+
         // Reuse the existing static member declaration if one exists
         auto MI = StaticDataMemberCache.find(V->getCanonicalDecl());
         if (MI != StaticDataMemberCache.end()) {
@@ -1327,7 +1330,9 @@ void CGDebugInfo::CollectRecordFields(
 
         // Bump field number for next field.
         ++fieldNo;
-      } else if (IncludeNestedTypes) {
+      } else if (CGM.getCodeGenOpts().EmitCodeView) {
+        // Debug info for nested types is included in the member list only for
+        // CodeView.
         if (const auto *nestedType = dyn_cast<TypeDecl>(I))
           if (!nestedType->isImplicit() &&
               nestedType->getDeclContext() == record)
diff --git a/test/CodeGenCXX/debug-info-codeview-var-templates.cpp b/test/CodeGenCXX/debug-info-codeview-var-templates.cpp
new file mode 100644
index 0000000000..0470c13368
--- /dev/null
+++ b/test/CodeGenCXX/debug-info-codeview-var-templates.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 %s -std=c++14 -triple=i686-pc-windows-msvc -debug-info-kind=limited -gcodeview -emit-llvm -o - | FileCheck %s
+
+// Don't emit static data member debug info for variable templates.
+// PR38004
+
+struct TestImplicit {
+  template <typename T>
+  static const __SIZE_TYPE__ size_var = sizeof(T);
+};
+int instantiate_test1() { return TestImplicit::size_var<int> + TestImplicit::size_var<TestImplicit>; }
+TestImplicit gv1;
+
+// CHECK: ![[empty:[0-9]+]] = !{}
+
+// CHECK: ![[A:[^ ]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "TestImplicit",
+// CHECK-SAME: elements: ![[empty]]
+
+template <typename T> bool vtpl;
+struct TestSpecialization {
+  template <typename T, typename U> static const auto sdm = vtpl<T>;
+  template <> static const auto sdm<int, int> = false;
+} gv2;
+
+// CHECK: ![[A:[^ ]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "TestSpecialization",
+// CHECK-SAME: elements: ![[empty]]
+
+template <class> bool a;
+template <typename> struct b;
+struct TestPartial {
+  template <typename... e> static auto d = a<e...>;
+  template <typename... e> static auto d<b<e...>> = d<e...>;
+} c;
+
+// CHECK: ![[A:[^ ]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "TestPartial",
+// CHECK-SAME: elements: ![[empty]]
-- 
2.50.1