[clang] inheritance fix for nomerge attribute

[xbolva00]

Summary

Discussed here: https://reviews.llvm.org/D119061#3310822

[aaron.ballman]

It looks like the precommit CI caught a few more places where we need to add quotes in the diagnostic.

clang/test/Sema/attr-nomerge-ast.cpp

9–17

Might as well drop the line and column info (then we can update the test easier and not have to worry about also updating those values; they're not what's under test anyway).

clang/test/Sema/attr-nomerge.cpp

11

I dug out the standard and stared at it, I no longer think this behavior in incorrect.

https://eel.is/c++draft/stmt.stmt#stmt.label-1.sentence-2

(The attribute is on the label decl level, not on the label statement level. As best I can tell, there is no way to write an attribute on a label statement.)

C2x follows suit with their grammar as well.

The things I learn about these languages... :-D

[xbolva00]

Addressed review feedback

[xbolva00]

clang/test/Sema/attr-nomerge.cpp

11

Ah, yeah, right

C++ standard is always cool to read = )

[aaron.ballman]

LGTM, thank you!

clang/include/clang/Basic/Attr.td

def Unlikely : StmtAttr {
   let Spellings = [CXX11<"", "unlikely", 201803>, C2x<"clang", "unlikely">];
   let Documentation = [LikelihoodDocs];
 }
 def : MutualExclusions<[Likely, Unlikely]>;
 
 def NoMerge : DeclOrStmtAttr {
   let Spellings = [Clang<"nomerge">];
   let Documentation = [NoMergeDocs];
-  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Function, Stmt], ErrorDiag,
                              "functions and statements">;
   let SimpleHandler = 1;
 }
 
 def MustTail : StmtAttr {
   let Spellings = [Clang<"musttail">];
   let Documentation = [MustTailDocs];

clang/lib/Sema/SemaStmtAttr.cpp

 
 static Attr *handleNoMergeAttr(Sema &S, Stmt *St, const ParsedAttr &A,
                                SourceRange Range) {
   NoMergeAttr NMA(S.Context, A);
   CallExprFinder CEF(S, St);
 
   if (!CEF.foundCallExpr()) {
     S.Diag(St->getBeginLoc(), diag::warn_nomerge_attribute_ignored_in_stmt)
-        << NMA.getSpelling();
+        << A;
     return nullptr;
   }
 
   return ::new (S.Context) NoMergeAttr(S.Context, A);
 }
 
 static Attr *handleMustTailAttr(Sema &S, Stmt *St, const ParsedAttr &A,
                                 SourceRange Range) {

clang/test/Parser/stmt-attributes.c

 
 void foobar(void) {
   __attribute__((nomerge)) bar();
   __attribute__(()) bar();                // expected-error {{expected identifier or '('}}
   __attribute__((unused, nomerge)) bar(); // expected-error {{expected identifier or '('}}
   __attribute__((nomerge, unused)) bar(); // expected-error {{expected identifier or '('}}
   __attribute__((nomerge(1, 2))) bar();   // expected-error {{'nomerge' attribute takes no arguments}}
   int x;
-  __attribute__((nomerge)) x = 10; // expected-warning {{nomerge attribute is ignored because there exists no call expression inside the statement}}
+  __attribute__((nomerge)) x = 10; // expected-warning {{'nomerge' attribute is ignored because there exists no call expression inside the statement}}
 
   __attribute__((nomerge)) label : bar(); // expected-error {{'nomerge' attribute only applies to functions and statements}}
 }
 
 int f(void);
 
 __attribute__((nomerge)) static int i; // expected-error {{'nomerge' attribute only applies to functions and statements}}

clang/test/Parser/stmt-attributes.m

 
 - (void)bar {
   __attribute__(()) [self foo];
   // expected-error@-1 {{missing '[' at start of message send expression}}
   // expected-error@-2 {{expected ']'}}
   // expected-error@-3 {{expected identifier or '('}}
   // expected-note@-4 {{to match this '['}}
   __attribute__((nomerge)) [self foo];
-  // expected-warning@-1 {{nomerge attribute is ignored because there exists no call expression inside the statement}}
+  // expected-warning@-1 {{'nomerge' attribute is ignored because there exists no call expression inside the statement}}
   __attribute__((nomerge)) [getTest() foo];
 
   __attribute__(()) ^{};
   // expected-error@-1 {{expected identifier or '('}}
   __attribute__((nomerge)) ^{};
-  // expected-warning@-1 {{nomerge attribute is ignored because there exists no call expression inside the statement}}
+  // expected-warning@-1 {{'nomerge' attribute is ignored because there exists no call expression inside the statement}}
   __attribute__((nomerge)) ^{ [self foo]; }();
 
   __attribute__(()) @try {
     [self foo];
   } @finally {
   }
 
   __attribute__((nomerge)) @try {
     [getTest() foo];
   } @finally {
   }
 
   __attribute__((nomerge)) (__bridge void *)self;
-  // expected-warning@-1 {{nomerge attribute is ignored because there exists no call expression inside the statement}}
+  // expected-warning@-1 {{'nomerge' attribute is ignored because there exists no call expression inside the statement}}
 
   __attribute__((nomerge)) self.hasFoobar;
-  // expected-warning@-1 {{nomerge attribute is ignored because there exists no call expression inside the statement}}
+  // expected-warning@-1 {{'nomerge' attribute is ignored because there exists no call expression inside the statement}}
 }
 @end

clang/test/Sema/attr-nomerge-ast.cpp

+// RUN: %clang_cc1 -ast-dump %s 2>&1 | FileCheck %s
+
+[[clang::nomerge]] void func();
+[[clang::nomerge]] void func();
+void func();
+[[clang::nomerge]] void func() {}
+
+// CHECK: FunctionDecl {{.*}} func 'void ()'
+// CHECK-NEXT: NoMergeAttr
+// CHECK-NEXT: FunctionDecl {{.*}} func 'void ()'
+// CHECK-NEXT: NoMergeAttr
+// CHECK-NEXT: FunctionDecl {{.*}} func 'void ()'
+// CHECK-NEXT: NoMergeAttr {{.*}} Inherited
+// CHECK-NEXT: FunctionDecl {{.*}} func 'void ()'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: NoMergeAttr

clang/test/Sema/attr-nomerge.cpp

 // RUN: %clang_cc1 -verify -fsyntax-only %s
 
 void bar();
 
 void foo() {
   [[clang::nomerge]] bar();
   [[clang::nomerge(1, 2)]] bar(); // expected-error {{'nomerge' attribute takes no arguments}}
   int x;
-  [[clang::nomerge]] x = 10; // expected-warning {{nomerge attribute is ignored because there exists no call expression inside the statement}}
+  [[clang::nomerge]] x = 10; // expected-warning {{'nomerge' attribute is ignored because there exists no call expression inside the statement}}
 
   [[clang::nomerge]] label: bar(); // expected-error {{'nomerge' attribute only applies to functions and statements}}
 
 }
 
 [[clang::nomerge]] int f();
 
 [[clang::nomerge]] static int i = f(); // expected-error {{'nomerge' attribute only applies to functions and statements}}