Fix template class debug info for Visual Studio visualizers

An earlier change eliminated spaces between the close brackets of nested
template lists.  Unfortunately that prevents the Windows debuggers from
matching some types to their corresponding visualizers (e.g., std::map).

This selects the SeparateTemplateClosers flag when generating CodeView.
Note that we were already making formatting adjustments under similar
circumstances for similar reasons.

This wasn't caught by existing tests because they were using only
-std=c++98.

Differential Revision: https://reviews.llvm.org/D79274
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index f92b21d..88ddb44 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -231,9 +231,12 @@
   // If we're emitting codeview, it's important to try to match MSVC's naming so
   // that visualizers written for MSVC will trigger for our class names. In
   // particular, we can't have spaces between arguments of standard templates
-  // like basic_string and vector.
-  if (CGM.getCodeGenOpts().EmitCodeView)
+  // like basic_string and vector, but we must have spaces between consecutive
+  // angle brackets that close nested template argument lists.
+  if (CGM.getCodeGenOpts().EmitCodeView) {
     PP.MSVCFormatting = true;
+    PP.SplitTemplateClosers = true;
+  }
 
   // Apply -fdebug-prefix-map.
   PP.Callbacks = &PrintCB;
diff --git a/clang/test/CodeGenCXX/debug-info-codeview-display-name.cpp b/clang/test/CodeGenCXX/debug-info-codeview-display-name.cpp
index ab3344b..15f625d 100644
--- a/clang/test/CodeGenCXX/debug-info-codeview-display-name.cpp
+++ b/clang/test/CodeGenCXX/debug-info-codeview-display-name.cpp
@@ -1,11 +1,19 @@
 // RUN: %clang_cc1 -fblocks -debug-info-kind=limited -gcodeview -emit-llvm %s \
-// RUN:       -o - -triple=x86_64-pc-win32 -std=c++98 | \
+// RUN:       -o - -triple=x86_64-pc-win32 -Wno-new-returns-null -std=c++98 | \
 // RUN:    grep -E 'DISubprogram|DICompositeType' | 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:       -o - -triple=x86_64-pc-win32 -Wno-new-returns-null -std=c++98 | \
 // RUN:    grep 'DISubprogram' | sed -e 's/.*name: "\([^"]*\)".*/"\1"/' | \
 // RUN:    FileCheck %s --check-prefix=CHECK --check-prefix=QUAL
+// RUN: %clang_cc1 -fblocks -debug-info-kind=limited -gcodeview -emit-llvm %s \
+// RUN:       -o - -triple=x86_64-pc-win32 -Wno-new-returns-null -std=c++11 | \
+// RUN:    grep -E 'DISubprogram|DICompositeType' | sed -e 's/.*name: "\([^"]*\)".*/"\1"/' | \
+// RUN:    FileCheck %s --check-prefix=CHECK --check-prefix=UNQUAL
+// RUN: %clang_cc1 -fblocks -debug-info-kind=limited -gcodeview -emit-llvm %s \
+// RUN:       -o - -triple=x86_64-pc-win32 -Wno-new-returns-null | \
+// RUN:    grep -E 'DISubprogram|DICompositeType' | sed -e 's/.*name: "\([^"]*\)".*/"\1"/' | \
+// RUN:    FileCheck %s --check-prefix=CHECK --check-prefix=UNQUAL
 
 void freefunc() { }
 // CHECK-DAG: "freefunc"
@@ -94,5 +102,7 @@
 
 template <typename A, typename B, typename C> struct ClassTemplate { A a; B b; C c; };
 ClassTemplate<char, short, ClassTemplate<int, int, int> > f;
-// This will only show up in normal debug builds.
+// This will only show up in normal debug builds.  The space in `> >` is
+// important for compatibility with Windows debuggers, so it should always be
+// there when generating CodeView.
 // UNQUAL-DAG: "ClassTemplate<char,short,ClassTemplate<int,int,int> >"