r350920 - [Sema] Make canPassInRegisters return true if the CXXRecordDecl passed

[Akira Hatanaka via cfe-commits]

Author: ahatanak
Date: Thu Jan 10 23:06:38 2019
New Revision: 350920

URL: http://llvm.org/viewvc/llvm-project?rev=350920&view=rev
Log:
[Sema] Make canPassInRegisters return true if the CXXRecordDecl passed
to it is a trivial_abi class.

A class that has all of its copy and move constructors deleted can still
be passed or returned in registers if the class is annotated with
trivial_abi.

This fixes PR39683.

Modified:
    cfe/trunk/lib/Sema/SemaDeclCXX.cpp
    cfe/trunk/test/CodeGenCXX/trivial_abi.cpp

Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=350920&r1=350919&r2=350920&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Thu Jan 10 23:06:38 2019
@@ -5886,6 +5886,9 @@ static bool canPassInRegisters(Sema &S,
   if (D->isDependentType() || D->isInvalidDecl())
     return false;
 
+  if (D->hasAttr<TrivialABIAttr>())
+    return true;
+
   // Clang <= 4 used the pre-C++11 rule, which ignores move operations.
   // The PS4 platform ABI follows the behavior of Clang 3.2.
   if (CCK == TargetInfo::CCK_ClangABI4OrPS4)

Modified: cfe/trunk/test/CodeGenCXX/trivial_abi.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/trivial_abi.cpp?rev=350920&r1=350919&r2=350920&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/trivial_abi.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/trivial_abi.cpp Thu Jan 10 23:06:38 2019
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fcxx-exceptions -fexceptions -emit-llvm -o - %s | FileCheck %s
-// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fcxx-exceptions -fexceptions -fclang-abi-compat=4.0 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++17 -fcxx-exceptions -fexceptions -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++17 -fcxx-exceptions -fexceptions -fclang-abi-compat=4.0 -emit-llvm -o - %s | FileCheck %s
 
 // CHECK: %[[STRUCT_SMALL:.*]] = type { i32* }
 // CHECK: %[[STRUCT_LARGE:.*]] = type { i32*, [128 x i32] }
@@ -43,6 +43,13 @@ struct HasNonTrivial {
   NonTrivial m;
 };
 
+struct __attribute__((trivial_abi)) CopyMoveDeleted {
+  CopyMoveDeleted(int);
+  CopyMoveDeleted(const CopyMoveDeleted &) = delete;
+  CopyMoveDeleted(CopyMoveDeleted &&) = delete;
+  int a;
+};
+
 // CHECK: define void @_Z14testParamSmall5Small(i64 %[[A_COERCE:.*]])
 // CHECK: %[[A:.*]] = alloca %[[STRUCT_SMALL]], align 8
 // CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_SMALL]], %[[STRUCT_SMALL]]* %[[A]], i32 0, i32 0
@@ -237,3 +244,11 @@ void calleeExceptionLarge(Large, Large);
 void testExceptionLarge() {
   calleeExceptionLarge(Large(), Large());
 }
+
+// A class with deleted copy and move constructors can still be passed or
+// returned in registers if the class is annotated with trivial_abi.
+
+// CHECK: define i64 @_Z19testCopyMoveDeletedi(i32 %
+CopyMoveDeleted testCopyMoveDeleted(int a) {
+  return a;
+}