[MS ABI] Don't crash while mangling recursive lambdas

We might get into bad situations where we try to embed the signature of
an inner lambda into an outer lambda which cannot work: the inner lambda
wants to embed the name of the outer lambda!

Instead, omit the return type for lambdas.

This fixes PR26105.

N.B.  While we are here, make lambdas nested within functions use an
artificial scope so that they can get demangled.

llvm-svn: 258003

1 files changed, 13 insertions, 6 deletions

diff --git a/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp b/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
index 999def87fc5..99384440a18 100644
--- a/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
+++ b/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
@@ -166,14 +166,14 @@ inline int define_lambda() {
   static auto lambda = [] { static int local; ++local; return local; };
 // First, we have the static local variable of type "<lambda_1>" inside of
 // "define_lambda".
-// CHECK-DAG: @"\01?lambda@?1??define_lambda@@YAHXZ@4V<lambda_1>@?1@YAHXZ@A"
+// CHECK-DAG: @"\01?lambda@?1??define_lambda@@YAHXZ@4V<lambda_1>@?0??1@YAHXZ@A"
 // Next, we have the "operator()" for "<lambda_1>" which is inside of
 // "define_lambda".
-// CHECK-DAG: @"\01??R<lambda_1>@?define_lambda@@YAHXZ@QBEHXZ"
+// CHECK-DAG: @"\01??R<lambda_1>@?0??define_lambda@@YAHXZ@QBE@XZ"
 // Finally, we have the local which is inside of "<lambda_1>" which is inside of
 // "define_lambda". Hooray.
-// MSVC2013-DAG: @"\01?local@?2???R<lambda_1>@?define_lambda@@YAHXZ@QBEHXZ@4HA"
-// MSVC2015-DAG: @"\01?local@?1???R<lambda_1>@?define_lambda@@YAHXZ@QBEHXZ@4HA"
+// MSVC2013-DAG: @"\01?local@?2???R<lambda_1>@?0??define_lambda@@YAHXZ@QBE@XZ@4HA"
+// MSVC2015-DAG: @"\01?local@?1???R<lambda_1>@?0??define_lambda@@YAHXZ@QBE@XZ@4HA"
   return lambda();
 }
 
@@ -182,12 +182,12 @@ void use_lambda_arg(T) {}
 
 inline void call_with_lambda_arg1() {
   use_lambda_arg([]{});
-  // CHECK-DAG: @"\01??$use_lambda_arg@V<lambda_1>@?call_with_lambda_arg1@@YAXXZ@@@YAXV<lambda_1>@?call_with_lambda_arg1@@YAXXZ@@Z"
+  // CHECK-DAG: @"\01??$use_lambda_arg@V<lambda_1>@?0??call_with_lambda_arg1@@YAXXZ@@@YAXV<lambda_1>@?0??call_with_lambda_arg1@@YAXXZ@@Z"
 }
 
 inline void call_with_lambda_arg2() {
   use_lambda_arg([]{});
-  // CHECK-DAG: @"\01??$use_lambda_arg@V<lambda_1>@?call_with_lambda_arg2@@YAXXZ@@@YAXV<lambda_1>@?call_with_lambda_arg2@@YAXXZ@@Z"
+  // CHECK-DAG: @"\01??$use_lambda_arg@V<lambda_1>@?0??call_with_lambda_arg2@@YAXXZ@@@YAXV<lambda_1>@?0??call_with_lambda_arg2@@YAXXZ@@Z"
 }
 
 int call_lambda() {
@@ -286,3 +286,10 @@ static union {
 };
 // CHECK-DAG: @"\01??$f@T<unnamed-type-$S1>@PR18204@@@PR18204@@YAHPAT<unnamed-type-$S1>@0@@Z"
 }
+
+int PR26105() {
+  auto add = [](int x) { return ([x](int y) { return x + y; }); };
+  return add(3)(4);
+}
+// CHECK-DAG: @"\01??R<lambda_0>@?0??PR26105@@YAHXZ@QBE@H@Z"
+// CHECK-DAG: @"\01??R<lambda_1>@?0???R<lambda_0>@?0??PR26105@@YAHXZ@QBE@H@Z@QBE@H@Z"