Emit a proper diagnostic when attempting to forward inalloca arguments

The previous assertion was relatively easy to trigger, and likely will
be easy to trigger going forward. EmitDelegateCallArg is relatively
popular.

This cleanly diagnoses PR28299 while I work on a proper solution.

llvm-svn: 348991

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 4757cd2ffae622e22fdab8b4ed0d59aa3dd4df59..b2c1eba06647fd271d1005604f6c8d08cc383c63 100644 (file)
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -3076,8 +3076,9 @@ void CodeGenFunction::EmitDelegateCallArg(CallArgList &args,
 
   QualType type = param->getType();
 
-  assert(!isInAllocaArgument(CGM.getCXXABI(), type) &&
-         "cannot emit delegate call arguments for inalloca arguments!");
+  if (isInAllocaArgument(CGM.getCXXABI(), type)) {
+    CGM.ErrorUnsupported(param, "forwarded non-trivially copyable parameter");
+  }
 
   // GetAddrOfLocalVar returns a pointer-to-pointer for references,
   // but the argument needs to be the original pointer.

diff --git a/clang/test/CodeGenCXX/inalloca-lambda.cpp b/clang/test/CodeGenCXX/inalloca-lambda.cpp
new file mode 100644 (file)
index 0000000..ac85ee1
--- /dev/null
+++ b/clang/test/CodeGenCXX/inalloca-lambda.cpp
@@ -0,0 +1,11 @@
+// RUN: not %clang_cc1 -triple i686-windows-msvc -emit-llvm -o /dev/null %s  2>&1 | FileCheck %s
+
+// PR28299
+// CHECK: error: cannot compile this forwarded non-trivially copyable parameter yet
+
+class A {
+  A(const A &);
+};
+typedef void (*fptr_t)(A);
+fptr_t fn1() { return [](A) {}; }
+