From 9bd6b77ac66fddadc50ca99ca327f1b7f9b0d6e4 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard@metafoo.co.uk>
Date: Tue, 14 Apr 2020 23:35:35 -0700
Subject: [PATCH] Don't print `&` as part of reference template arguments.

In passing, also generalize the mechanism used to allow Decl's printName
functions to override qualified name printing.
---
 clang/lib/AST/Decl.cpp                        | 15 ++++++++++++---
 clang/lib/AST/TemplateBase.cpp                | 10 +++-------
 clang/test/CodeGenCXX/debug-info-template.cpp |  4 +---
 3 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 1eb8547..8d98e1f 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -1542,10 +1542,19 @@ void NamedDecl::printQualifiedName(raw_ostream &OS,
     return;
   }
   printNestedNameSpecifier(OS, P);
-  if (getDeclName() || isa<DecompositionDecl>(this))
+  if (getDeclName())
     OS << *this;
-  else
-    OS << "(anonymous)";
+  else {
+    // Give the printName override a chance to pick a different name before we
+    // fall back to "(anonymous)".
+    SmallString<64> NameBuffer;
+    llvm::raw_svector_ostream NameOS(NameBuffer);
+    printName(NameOS);
+    if (NameBuffer.empty())
+      OS << "(anonymous)";
+    else
+      OS << NameBuffer;
+  }
 }
 
 void NamedDecl::printNestedNameSpecifier(raw_ostream &OS) const {
diff --git a/clang/lib/AST/TemplateBase.cpp b/clang/lib/AST/TemplateBase.cpp
index c122213..6a3d2b3 100644
--- a/clang/lib/AST/TemplateBase.cpp
+++ b/clang/lib/AST/TemplateBase.cpp
@@ -352,13 +352,9 @@ void TemplateArgument::print(const PrintingPolicy &Policy,
 
   case Declaration: {
     NamedDecl *ND = getAsDecl();
-    Out << '&';
-    if (ND->getDeclName()) {
-      // FIXME: distinguish between pointer and reference args?
-      ND->printQualifiedName(Out);
-    } else {
-      Out << "(anonymous)";
-    }
+    if (!getParamTypeForDecl()->isReferenceType())
+      Out << '&';
+    ND->printQualifiedName(Out);
     break;
   }
 
diff --git a/clang/test/CodeGenCXX/debug-info-template.cpp b/clang/test/CodeGenCXX/debug-info-template.cpp
index 4b330a0..a07222a 100644
--- a/clang/test/CodeGenCXX/debug-info-template.cpp
+++ b/clang/test/CodeGenCXX/debug-info-template.cpp
@@ -129,9 +129,7 @@ struct NN {
 // CHECK: [[NNV]] = distinct !DIGlobalVariable(name: "nn"
 // CHECK-SAME:                                 type: ![[NNT:[0-9]+]]
 
-// FIXME: these parameters should probably be rendered as 'glb' rather than
-// '&glb', since they're references, not pointers.
-// CHECK: ![[NNT]] ={{.*}}!DICompositeType(tag: DW_TAG_structure_type, name: "NN<tmpl_impl, &glb, &glb>",
+// CHECK: ![[NNT]] ={{.*}}!DICompositeType(tag: DW_TAG_structure_type, name: "NN<tmpl_impl, glb, glb>",
 // CHECK-SAME:             templateParams: [[NNARGS:![0-9]*]]
 // CHECK-SAME:             identifier:
 // CHECK: [[NNARGS]] = !{[[NNARG1:![0-9]*]], [[NNARG2:![0-9]*]], [[NNARG3:![0-9]*]]}
-- 
2.7.4