Convert some ObjC msgSends to runtime calls.

It is faster to directly call the ObjC runtime for methods such as alloc/allocWithZone instead of sending a message to those functions.

This patch adds support for converting messages to alloc/allocWithZone to their equivalent runtime calls.

Tests included for the positive case of applying this transformation, negative tests that we ensure we only convert "alloc" to objc_alloc, not "alloc2", and also a driver test to ensure we enable this only for supported runtime versions.

Reviewed By: rjmccall

https://reviews.llvm.org/D55349

llvm-svn: 348687

2 files changed, 87 insertions, 0 deletions

diff --git a/clang/test/CodeGenObjC/convert-messages-to-runtime-calls.m b/clang/test/CodeGenObjC/convert-messages-to-runtime-calls.m
new file mode 100644
index 00000000000..0a018204f3d
--- /dev/null
+++ b/clang/test/CodeGenObjC/convert-messages-to-runtime-calls.m
@@ -0,0 +1,80 @@
+// RUN: %clang_cc1 -fobjc-runtime=macosx-10.10.0 -emit-llvm -o - %s -fno-objc-convert-messages-to-runtime-calls | FileCheck %s --check-prefix=MSGS
+// RUN: %clang_cc1 -fobjc-runtime=macosx-10.10.0 -emit-llvm -o - %s | FileCheck %s --check-prefix=CALLS
+// RUN: %clang_cc1 -fobjc-runtime=macosx-10.9.0 -emit-llvm -o - %s | FileCheck %s --check-prefix=MSGS
+// RUN: %clang_cc1 -fobjc-runtime=macosx-fragile-10.10.0 -emit-llvm -o - %s | FileCheck %s --check-prefix=MSGS
+// RUN: %clang_cc1 -fobjc-runtime=ios-8.0 -emit-llvm -o - %s | FileCheck %s --check-prefix=CALLS
+// RUN: %clang_cc1 -fobjc-runtime=ios-7.0 -emit-llvm -o - %s | FileCheck %s --check-prefix=MSGS
+// Note: This line below is for tvos for which the driver passes through to use the ios9.0 runtime.
+// RUN: %clang_cc1 -fobjc-runtime=ios-9.0 -emit-llvm -o - %s | FileCheck %s --check-prefix=CALLS
+// RUN: %clang_cc1 -fobjc-runtime=watchos-2.0 -emit-llvm -o - %s | FileCheck %s --check-prefix=CALLS
+
+#define nil (id)0
+
+@interface NSObject
++ (id)alloc;
++ (id)allocWithZone:(void*)zone;
++ (id)alloc2;
+@end
+
+// CHECK-LABEL: define {{.*}}void @test1
+void test1(id x) {
+  // MSGS: {{call.*@objc_msgSend}}
+  // MSGS: {{call.*@objc_msgSend}}
+  // CALLS: {{call.*@objc_alloc}}
+  // CALLS: {{call.*@objc_allocWithZone}}
+  [NSObject alloc];
+  [NSObject allocWithZone:nil];
+}
+
+// CHECK-LABEL: define {{.*}}void @test2
+void test2(void* x) {
+  // MSGS: {{call.*@objc_msgSend}}
+  // MSGS: {{call.*@objc_msgSend}}
+  // MSGS: {{call.*@objc_msgSend}}
+  // CALLS: {{call.*@objc_msgSend}}
+  // CALLS: {{call.*@objc_msgSend}}
+  // CALLS: {{call.*@objc_msgSend}}
+  [NSObject alloc2];
+  [NSObject allocWithZone:(void*)-1];
+  [NSObject allocWithZone:x];
+}
+
+@class A;
+@interface B
++ (A*) alloc;
++ (A*)allocWithZone:(void*)zone;
+@end
+
+// Make sure we get a bitcast on the return type as the
+// call will return i8* which we have to cast to A*
+// CHECK-LABEL: define {{.*}}void @test_alloc_class_ptr
+A* test_alloc_class_ptr() {
+  // CALLS: {{call.*@objc_alloc}}
+  // CALLS-NEXT: bitcast i8*
+  // CALLS-NEXT: ret
+  return [B alloc];
+}
+
+// Make sure we get a bitcast on the return type as the
+// call will return i8* which we have to cast to A*
+// CHECK-LABEL: define {{.*}}void @test_alloc_class_ptr
+A* test_allocWithZone_class_ptr() {
+  // CALLS: {{call.*@objc_allocWithZone}}
+  // CALLS-NEXT: bitcast i8*
+  // CALLS-NEXT: ret
+  return [B allocWithZone:nil];
+}
+
+
+@interface C
++ (id)allocWithZone:(int)intArg;
+@end
+
+// Make sure we only accept pointer types
+// CHECK-LABEL: define {{.*}}void @test_allocWithZone_int
+C* test_allocWithZone_int() {
+  // MSGS: {{call.*@objc_msgSend}}
+  // CALLS: {{call.*@objc_msgSend}}
+  return [C allocWithZone:3];
+}
+
diff --git a/clang/test/Driver/objc-convert-messages-to-runtime-calls.m b/clang/test/Driver/objc-convert-messages-to-runtime-calls.m
new file mode 100644
index 00000000000..ed7be571eb5
--- /dev/null
+++ b/clang/test/Driver/objc-convert-messages-to-runtime-calls.m
@@ -0,0 +1,7 @@
+// RUN: %clang %s -### -o %t.o 2>&1 -fsyntax-only -fobjc-convert-messages-to-runtime-calls -fno-objc-convert-messages-to-runtime-calls -target x86_64-apple-macosx10.10.0 | FileCheck  %s --check-prefix=DISABLE
+// RUN: %clang %s -### -o %t.o 2>&1 -fsyntax-only -fno-objc-convert-messages-to-runtime-calls -fobjc-convert-messages-to-runtime-calls -target x86_64-apple-macosx10.10.0 | FileCheck  %s --check-prefix=ENABLE
+
+// Check that we pass fobjc-convert-messages-to-runtime-calls only when supported, and not explicitly disabled.
+
+// DISABLE: "-fno-objc-convert-messages-to-runtime-calls"
+// ENABLE-NOT: "-fno-objc-convert-messages-to-runtime-calls"