From e408cba84f8a9471bb26deca8d9aac049a924847 Mon Sep 17 00:00:00 2001
From: Zequan Wu <zequanwu@google.com>
Date: Wed, 10 Jun 2020 09:37:58 -0700
Subject: [PATCH] [AST] Mangle LambdaContextDecl for top level decl

Summary:

Bug filed here: https://bugs.llvm.org/show_bug.cgi?id=45213

To resolve it, we let the checks for mangling LambdaContextDecl to be analogous to ItaniumMangle strategy: https://github.com/llvm/llvm-project/blob/master/clang/lib/AST/ItaniumMangle.cpp#L1829

Differential Revision: https://reviews.llvm.org/D80153
---
 clang/lib/AST/MicrosoftMangle.cpp         | 6 +++---
 clang/test/CodeGenCXX/mangle-ms-cxx17.cpp | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index ca628b3..529f301 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -947,12 +947,12 @@ void MicrosoftCXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
 
           mangleSourceName(Name);
 
-          // If the context of a closure type is an initializer for a class
-          // member (static or nonstatic), it is encoded in a qualified name.
+          // If the context is a variable or a class member and not a parameter,
+          // it is encoded in a qualified name.
           if (LambdaManglingNumber && LambdaContextDecl) {
             if ((isa<VarDecl>(LambdaContextDecl) ||
                  isa<FieldDecl>(LambdaContextDecl)) &&
-                LambdaContextDecl->getDeclContext()->isRecord()) {
+                !isa<ParmVarDecl>(LambdaContextDecl)) {
               mangleUnqualifiedName(cast<NamedDecl>(LambdaContextDecl));
             }
           }
diff --git a/clang/test/CodeGenCXX/mangle-ms-cxx17.cpp b/clang/test/CodeGenCXX/mangle-ms-cxx17.cpp
index 897f0d6..751fcc4 100644
--- a/clang/test/CodeGenCXX/mangle-ms-cxx17.cpp
+++ b/clang/test/CodeGenCXX/mangle-ms-cxx17.cpp
@@ -19,3 +19,11 @@ double b;
 
 // CHECK-DAG: "?$S4@@3US@@B"
 const auto [x2, y2] = f();
+
+// CHECK-DAG: "?i1@@3V<lambda_1>@0@B"
+inline const auto i1 = [](auto x) { return 0; };
+// CHECK-DAG: "?i2@@3V<lambda_1>@0@B"
+inline const auto i2 = [](auto x) { return 1; };
+// CHECK-DAG: "??$?RH@<lambda_1>@i1@@QBE?A?<auto>@@H@Z"
+// CHECK-DAG: "??$?RH@<lambda_1>@i2@@QBE?A?<auto>@@H@Z"
+int g() {return i1(1) + i2(1); }
-- 
2.7.4