IRGen: Always eliminate frame pointers of leaf functions

rdar://20933449

Author: aschwaighofer

lib/IRGen/IRGenModule.cpp

@@ -988,7 +988,7 @@ bool swift::irgen::shouldRemoveTargetFeature(StringRef feature) {
 
 void IRGenModule::setHasFramePointer(llvm::AttrBuilder &Attrs,
                                      bool HasFramePointer) {
-  Attrs.addAttribute("frame-pointer", HasFramePointer ? "all" : "none");
+  Attrs.addAttribute("frame-pointer", HasFramePointer ? "non-leaf" : "none");
 }
 
 void IRGenModule::setHasFramePointer(llvm::Function *F,

test/IRGen/c_globals.swift

@@ -32,4 +32,4 @@ public func testCaptureGlobal() {
 }
 
 // CHECK-DAG: attributes [[CLANG_FUNC_ATTR]] = { noinline nounwind {{.*}}"frame-pointer"="all"{{.*}}
-// CHECK-DAG: attributes [[SWIFT_FUNC_ATTR]] = { {{.*}}"frame-pointer"="all" {{.*}}"target-cpu"
+// CHECK-DAG: attributes [[SWIFT_FUNC_ATTR]] = { {{.*}}"frame-pointer"="non-leaf" {{.*}}"target-cpu"

test/IRGen/framepointer.sil

@@ -0,0 +1,48 @@
+// RUN: %target-swift-frontend -primary-file %s -emit-ir | %FileCheck %s --check-prefix=CHECK
+// RUN: %target-swift-frontend -primary-file %s -S | %FileCheck %s  --check-prefix=CHECKASM --check-prefix=CHECKASM-%target-os-%target-cpu
+
+sil_stage canonical
+
+import Swift
+
+sil @leaf_function_no_frame_pointer : $@convention(thin) (Int32) -> Int32 {
+entry(%i : $Int32):
+  return %i : $Int32
+}
+
+sil @non_leaf_function_with_frame_pointer : $@convention(thin) (Int32) -> Int32 {
+entry(%i : $Int32):
+  %f = function_ref @leaf_function_no_frame_pointer : $@convention(thin) (Int32) -> Int32
+  %r = apply %f(%i) : $@convention(thin) (Int32) -> Int32
+  return %r : $Int32
+}
+
+// CHECK: define{{.*}} swiftcc i32 @leaf_function_no_frame_pointer(i32 %0) [[ATTR:#.*]] {
+// CHECK: entry:
+// CHECK:   ret i32 %0
+// CHECK: }
+
+// CHECK: define{{.*}} swiftcc i32 @non_leaf_function_with_frame_pointer(i32 %0) [[ATTR]] {
+// CHECK: entry:
+// CHECK:   %1 = call swiftcc i32 @leaf_function_no_frame_pointer(i32 %0)
+// CHECK:   ret i32 %1
+// CHECK: }
+
+// CHECK: attributes [[ATTR]] = {{{.*}}"frame-pointer"="non-leaf"
+
+// Silence other os-archs.
+// CHECKASM: {{.*}}
+
+// CHECKASM-macosx-x86_64-LABEL: _leaf_function_no_frame_pointer:
+// CHECKASM-macosx-x86_64-NOT: push
+// CHECKASM-macosx-x86_64: movl    %edi, %eax
+// CHECKASM-macosx-x86_64-NOT: pop
+// CHECKASM-macosx-x86_64: ret
+
+
+// CHECKASM-macosx-x86_64-LABEL: _non_leaf_function_with_frame_pointer:
+// CHECKASM-macosx-x86_64:   pushq %rbp
+// CHECKASM-macosx-x86_64:   movq %rsp, %rbp
+// CHECKASM-macosx-x86_64:   callq _leaf_function_no_frame_pointer
+// CHECKASM-macosx-x86_64:   popq %rbp
+// CHECKASM-macosx-x86_64:   ret

test/Misc/tbi.sil

@@ -19,19 +19,13 @@
 
 // NO_TBI-LABEL: .globl  _testTBI
 // NO_TBI: _testTBI
-// NO_TBI-NEXT: stp
-// NO_TBI-NEXT: mov
 // NO_TBI-NEXT: and
 // NO_TBI-NEXT: ldr
-// NO_TBI-NEXT: ldp
 // NO_TBI-NEXT: ret
 
 // TBI-LABEL: .globl  _testTBI
 // TBI: _testTBI:
-// TBI-NEXT: stp
-// TBI-NEXT: mov
 // TBI-NEXT: ldr
-// TBI-NEXT: ldp
 // TBI-NEXT: ret
 
 sil_stage canonical