Add no_instrument_function attribute to Objective C methods as well

[hiraditya]

Summary

There are functions where we do not want function instrumentation which is why we have __attribute__((no_instrument_function)). Extending this functionality to disable instrumentation for Objective-C methods as well. Objective C methods like +load run premain and having instrumentation on them causes runtime errors depending on the implementation of __cyg_profile_func_enter etc. functions

[hiraditya]

Still working on adding the testcase.

[hiraditya]

Testcase ready.

[rjmccall]

LGTM

[aaron.ballman]

CI is currently broken, so there's a test here that needs updating: https://reviews.llvm.org/harbormaster/unit/view/1389113/

Also, this should have at least one SemaObjC test to demonstrate that we no longer diagnose this as an unknown attribute in that case.

[hiraditya]

Added SemaObjc test case.

[aaron.ballman]

LGTM, thanks!

[hiraditya]

clang-format

clang/include/clang/Basic/Attr.td

 def NoReturn : InheritableAttr {
   let Spellings = [GCC<"noreturn">, Declspec<"noreturn">];
   // FIXME: Does GCC allow this on the function instead?
   let Documentation = [Undocumented];
 }
 
 def NoInstrumentFunction : InheritableAttr {
   let Spellings = [GCC<"no_instrument_function">];
-  let Subjects = SubjectList<[Function]>;
+  let Subjects = SubjectList<[Function, ObjCMethod]>;
   let Documentation = [Undocumented];
   let SimpleHandler = 1;
 }
 
 def NoProfileFunction : InheritableAttr {
   let Spellings = [GCC<"no_profile_instrument_function">];
   let Subjects = SubjectList<[Function]>;
   let Documentation = [NoProfileInstrumentFunctionDocs];

clang/test/CodeGen/instrument-objc-method.m

+// RUN: %clang_cc1 -S -triple x86_64-apple-darwin10 -debug-info-kind=standalone -emit-llvm -o - %s -finstrument-functions | FileCheck %s
+// RUN: %clang_cc1 -S -triple x86_64-apple-darwin10 -debug-info-kind=standalone -emit-llvm -o - %s -finstrument-function-entry-bare | FileCheck -check-prefix=BARE %s
+
+@interface ObjCClass
+@end
+
+@implementation ObjCClass
+
+// CHECK: @"\01+[ObjCClass initialize]"
+// CHECK: call void @__cyg_profile_func_enter
+// CHECK: call void @__cyg_profile_func_exit
+// BARE: @"\01+[ObjCClass initialize]"
+// BARE: call void @__cyg_profile_func_enter
++ (void)initialize {
+}
+
+// CHECK: @"\01+[ObjCClass load]"
+// CHECK-NOT: call void @__cyg_profile_func_enter
+// BARE: @"\01+[ObjCClass load]"
+// BARE-NOT: call void @__cyg_profile_func_enter
++ (void)load __attribute__((no_instrument_function)) {
+}
+
+// CHECK: @"\01-[ObjCClass dealloc]"
+// CHECK-NOT: call void @__cyg_profile_func_enter
+// BARE: @"\01-[ObjCClass dealloc]"
+// BARE-NOT: call void @__cyg_profile_func_enter
+- (void)dealloc __attribute__((no_instrument_function)) {
+}
+
+// CHECK: declare void @__cyg_profile_func_enter(i8*, i8*)
+// CHECK: declare void @__cyg_profile_func_exit(i8*, i8*)
+// BARE: declare void @__cyg_profile_func_enter_bare
+@end

clang/test/Misc/pragma-attribute-supported-attributes-list.test

 // CHECK-NEXT: Naked (SubjectMatchRule_function)
 // CHECK-NEXT: NoBuiltin (SubjectMatchRule_function)
 // CHECK-NEXT: NoCommon (SubjectMatchRule_variable)
 // CHECK-NEXT: NoDebug (SubjectMatchRule_type_alias, SubjectMatchRule_hasType_functionType, SubjectMatchRule_objc_method, SubjectMatchRule_variable_not_is_parameter)
 // CHECK-NEXT: NoDestroy (SubjectMatchRule_variable)
 // CHECK-NEXT: NoDuplicate (SubjectMatchRule_function)
 // CHECK-NEXT: NoEscape (SubjectMatchRule_variable_is_parameter)
 // CHECK-NEXT: NoInline (SubjectMatchRule_function)
-// CHECK-NEXT: NoInstrumentFunction (SubjectMatchRule_function)
+// CHECK-NEXT: NoInstrumentFunction (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: NoMerge (SubjectMatchRule_function)
 // CHECK-NEXT: NoMicroMips (SubjectMatchRule_function)
 // CHECK-NEXT: NoMips16 (SubjectMatchRule_function)
 // CHECK-NEXT: NoProfileFunction (SubjectMatchRule_function)
 // CHECK-NEXT: NoSanitize (SubjectMatchRule_function, SubjectMatchRule_objc_method, SubjectMatchRule_variable_is_global)
 // CHECK-NEXT: NoSanitizeSpecific (SubjectMatchRule_function, SubjectMatchRule_variable_is_global)
 // CHECK-NEXT: NoSpeculativeLoadHardening (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: NoSplitStack (SubjectMatchRule_function)

clang/test/SemaObjC/attr-noinstrument.m

+// RUN: %clang_cc1 -fsyntax-only -triple x86_64-apple-darwin10.4 -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1 -x objective-c++ -fsyntax-only -triple x86_64-apple-darwin10.4 -verify -Wno-objc-root-class %s
+
+// expected-no-diagnostics
+@interface A
++ (void)F __attribute__((no_instrument_function)); // no warning
+- (void)f __attribute__((objc_direct, no_instrument_function));
+- (void)g;
+@end
+
+@implementation A
++ (void)F __attribute__((no_instrument_function)) {
+  [self F];
+}
+
+- (void)f {
+  [self g];
+}
+
+- (void)g {
+}
+@end