[clang][frontend] Support applying the annotate attribute to statements

clang/include/clang/AST/Attr.h

@@ -197,6 +197,23 @@ class InheritableParamAttr : public InheritableAttr {
   }
 };
 
+class InheritableParamOrStmtAttr : public InheritableParamAttr {
+protected:
+  InheritableParamOrStmtAttr(ASTContext &Context,
+                             const AttributeCommonInfo &CommonInfo,
+                             attr::Kind AK, bool IsLateParsed,
+                             bool InheritEvenIfAlreadyPresent)
+      : InheritableParamAttr(Context, CommonInfo, AK, IsLateParsed,
+                             InheritEvenIfAlreadyPresent) {}
+
+public:
+  // Implement isa/cast/dyncast/etc.
+  static bool classof(const Attr *A) {
+    return A->getKind() >= attr::FirstInheritableParamOrStmtAttr &&
+           A->getKind() <= attr::LastInheritableParamOrStmtAttr;
+  }
+};
+
 class HLSLAnnotationAttr : public InheritableAttr {
 protected:
   HLSLAnnotationAttr(ASTContext &Context, const AttributeCommonInfo &CommonInfo,

clang/include/clang/Basic/Attr.td

@@ -759,6 +759,11 @@ class TargetSpecificAttr<TargetSpec target> {
 /// redeclarations, even when it's written on a parameter.
 class InheritableParamAttr : InheritableAttr;
 
+/// A attribute that is either a declaration attribute or a statement attribute,
+/// and if used as a declaration attribute, is inherited by later
+/// redeclarations, even when it's written on a parameter.
+class InheritableParamOrStmtAttr : InheritableParamAttr;
+
 /// An attribute which changes the ABI rules for a specific parameter.
 class ParameterABIAttr : InheritableParamAttr {
   let Subjects = SubjectList<[ParmVar]>;
@@ -928,7 +933,7 @@ def AnalyzerNoReturn : InheritableAttr {
   let Documentation = [Undocumented];
 }
 
-def Annotate : InheritableParamAttr {
+def Annotate : InheritableParamOrStmtAttr {
   let Spellings = [Clang<"annotate">];
   let Args = [StringArgument<"Annotation">, VariadicExprArgument<"Args">];
   // Ensure that the annotate attribute can be used with

clang/lib/Sema/SemaStmtAttr.cpp

@@ -242,6 +242,24 @@ static Attr *handleNoConvergentAttr(Sema &S, Stmt *St, const ParsedAttr &A,
   return ::new (S.Context) NoConvergentAttr(S.Context, A);
 }
 
+static Attr *handleAnnotateAttr(Sema &S, Stmt *St, const ParsedAttr &A,
+                                SourceRange Range) {
+  // Make sure that there is a string literal as the annotation's first
+  // argument.
+  StringRef Str;
+  if (!S.checkStringLiteralArgumentAttr(A, 0, Str))
+    return nullptr;
+
+  llvm::SmallVector<Expr *, 4> Args;
+  Args.reserve(A.getNumArgs() - 1);
+  for (unsigned Idx = 1; Idx < A.getNumArgs(); Idx++) {
+    assert(!A.isArgIdent(Idx));
+    Args.push_back(A.getArgAsExpr(Idx));
+  }
+
+  return AnnotateAttr::Create(S.Context, Str, Args.data(), Args.size(), A);
+}
+
 template <typename OtherAttr, int DiagIdx>
 static bool CheckStmtInlineAttr(Sema &SemaRef, const Stmt *OrigSt,
                                 const Stmt *CurSt,
@@ -679,6 +697,8 @@ static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A,
     return handleMSConstexprAttr(S, St, A, Range);
   case ParsedAttr::AT_NoConvergent:
     return handleNoConvergentAttr(S, St, A, Range);
+  case ParsedAttr::AT_Annotate:
+    return handleAnnotateAttr(S, St, A, Range);
   default:
     // N.B., ClangAttrEmitter.cpp emits a diagnostic helper that ensures a
     // declaration attribute is not written on a statement, but this code is

clang/lib/Sema/SemaTemplateInstantiate.cpp

@@ -1537,6 +1537,7 @@ namespace {
                           NamedDecl *FirstQualifierInScope = nullptr,
                           bool AllowInjectedClassName = false);
 
+    const AnnotateAttr *TransformAnnotateAttr(const AnnotateAttr *AA);
     const CXXAssumeAttr *TransformCXXAssumeAttr(const CXXAssumeAttr *AA);
     const LoopHintAttr *TransformLoopHintAttr(const LoopHintAttr *LH);
     const NoInlineAttr *TransformStmtNoInlineAttr(const Stmt *OrigS,
@@ -2125,6 +2126,19 @@ TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
                                          Arg, PackIndex);
 }
 
+const AnnotateAttr *
+TemplateInstantiator::TransformAnnotateAttr(const AnnotateAttr *AA) {
+  SmallVector<Expr *> Args;
+  for (Expr *Arg : AA->args()) {
+    ExprResult Res = getDerived().TransformExpr(Arg);
+    if (!Res.isUsable())
+      return AA;
+    Args.push_back(Res.get());
+  }
+  return AnnotateAttr::CreateImplicit(getSema().Context, AA->getAnnotation(),
+                                      Args.data(), Args.size(), AA->getRange());
+}
+
 const CXXAssumeAttr *
 TemplateInstantiator::TransformCXXAssumeAttr(const CXXAssumeAttr *AA) {
   ExprResult Res = getDerived().TransformExpr(AA->getAssumption());

clang/test/AST/attr-print-emit.cpp

@@ -78,6 +78,9 @@ class C {
 ANNOTATE_ATTR int annotated_attr ANNOTATE_ATTR = 0;
 // CHECK: __attribute__((annotate("Annotated"))) int annotated_attr __attribute__((annotate("Annotated"))) = 0;
 
+void increment() { [[clang::annotate("Annotated")]] annotated_attr++; }
+// CHECK: {{\[\[}}clang::annotate("Annotated")]] annotated_attr++;
+
 // FIXME: We do not print the attribute as written after the type specifier.
 int ANNOTATE_ATTR annotated_attr_fixme = 0;
 // CHECK: __attribute__((annotate("Annotated"))) int annotated_attr_fixme = 0;

clang/test/Sema/annotate.c

@@ -3,10 +3,12 @@
 void __attribute__((annotate("foo"))) foo(float *a) {
   __attribute__((annotate("bar"))) int x;
   [[clang::annotate("bar")]] int x2;
+  [[clang::annotate("bar")]] x2 += 1;
   __attribute__((annotate(1))) int y; // expected-error {{expected string literal as argument of 'annotate' attribute}}
   [[clang::annotate(1)]] int y2; // expected-error {{expected string literal as argument of 'annotate' attribute}}
   __attribute__((annotate("bar", 1))) int z;
   [[clang::annotate("bar", 1)]] int z2;
+  [[clang::annotate("bar", 1)]] z2 += 1;
 
   int u = __builtin_annotation(z, (char*) 0); // expected-error {{second argument to __builtin_annotation must be a non-wide string constant}}
   int v = __builtin_annotation(z, (char*) L"bar"); // expected-error {{second argument to __builtin_annotation must be a non-wide string constant}}
@@ -15,4 +17,5 @@ void __attribute__((annotate("foo"))) foo(float *a) {
 
   __attribute__((annotate())) int c; // expected-error {{'annotate' attribute takes at least 1 argument}}
   [[clang::annotate()]] int c2;      // expected-error {{'annotate' attribute takes at least 1 argument}}
+  [[clang::annotate()]] c2 += 1;     // expected-error {{'annotate' attribute takes at least 1 argument}}
 }

clang/test/SemaTemplate/attributes.cpp

@@ -65,6 +65,17 @@ namespace attribute_annotate {
 template<typename T> [[clang::annotate("ANNOTATE_FOO"), clang::annotate("ANNOTATE_BAR")]] void HasAnnotations();
 void UseAnnotations() { HasAnnotations<int>(); }
 
+// CHECK: FunctionTemplateDecl {{.*}} HasStmtAnnotations
+// CHECK:   AnnotateAttr {{.*}} "ANNOTATE_BAZ"
+// CHECK: FunctionDecl {{.*}} HasStmtAnnotations
+// CHECK:   TemplateArgument type 'int'
+// CHECK:   AnnotateAttr {{.*}} "ANNOTATE_BAZ"
+template<typename T> void HasStmtAnnotations() {
+  int x = 0;
+  [[clang::annotate("ANNOTATE_BAZ")]] x++;
+}
+void UseStmtAnnotations() { HasStmtAnnotations<int>(); }
+
 // CHECK:      FunctionTemplateDecl {{.*}} HasPackAnnotations
 // CHECK-NEXT:   NonTypeTemplateParmDecl {{.*}} referenced 'int' depth 0 index 0 ... Is
 // CHECK-NEXT:   FunctionDecl {{.*}} HasPackAnnotations 'void ()'
@@ -95,6 +106,33 @@ void UseAnnotations() { HasAnnotations<int>(); }
 template <int... Is> [[clang::annotate("ANNOTATE_BAZ", Is...)]] void HasPackAnnotations();
 void UsePackAnnotations() { HasPackAnnotations<1, 2, 3>(); }
 
+// CHECK:      FunctionTemplateDecl {{.*}} HasStmtPackAnnotations
+// CHECK-NEXT:   NonTypeTemplateParmDecl {{.*}} referenced 'int' depth 0 index 0 ... Is
+// CHECK-NEXT:   FunctionDecl {{.*}} HasStmtPackAnnotations 'void ()'
+// CHECK:          AttributedStmt {{.*}}
+// CHECK-NEXT:       AnnotateAttr {{.*}} "ANNOTATE_QUUX"
+// CHECK-NEXT:         PackExpansionExpr {{.*}} '<dependent type>'
+// CHECK-NEXT:           DeclRefExpr {{.*}} 'int' NonTypeTemplateParm {{.*}} 'Is' 'int'
+// CHECK:        FunctionDecl {{.*}} used HasStmtPackAnnotations 'void ()'
+// CHECK-NEXT:     TemplateArgument{{.*}} pack
+// CHECK-NEXT:       TemplateArgument{{.*}} integral '1'
+// CHECK-NEXT:       TemplateArgument{{.*}} integral '2'
+// CHECK-NEXT:       TemplateArgument{{.*}} integral '3'
+// CHECK:          AttributedStmt {{.*}}
+// CHECK-NEXT:       AnnotateAttr {{.*}} "ANNOTATE_QUUX"
+// CHECK-NEXT:         PackExpansionExpr {{.*}}
+// CHECK-NEXT:         SubstNonTypeTemplateParmPackExpr {{.*}}
+// CHECK-NEXT:         NonTypeTemplateParmDecl {{.*}} referenced 'int' depth 0 index 0 ... Is
+// CHECK-NEXT:           TemplateArgument pack '<1, 2, 3>'
+// CHECK-NEXT:             TemplateArgument integral '1'
+// CHECK-NEXT:             TemplateArgument integral '2'
+// CHECK-NEXT:             TemplateArgument integral '3'
+template <int... Is> void HasStmtPackAnnotations() {
+  int x = 0;
+  [[clang::annotate("ANNOTATE_QUUX", Is...)]] x++;
+}
+void UseStmtPackAnnotations() { HasStmtPackAnnotations<1, 2, 3>(); }
+
 template <int... Is> [[clang::annotate(Is...)]] void HasOnlyPackAnnotation() {} // expected-error {{expected string literal as argument of 'annotate' attribute}}
 
 void UseOnlyPackAnnotations() {

clang/utils/TableGen/ClangAttrEmitter.cpp

@@ -3295,6 +3295,7 @@ static const AttrClassDescriptor AttrClassDescriptors[] = {
   { "INHERITABLE_ATTR", "InheritableAttr" },
   { "DECL_OR_TYPE_ATTR", "DeclOrTypeAttr" },
   { "INHERITABLE_PARAM_ATTR", "InheritableParamAttr" },
+  { "INHERITABLE_PARAM_OR_STMT_ATTR", "InheritableParamOrStmtAttr" },
   { "PARAMETER_ABI_ATTR", "ParameterABIAttr" },
   { "HLSL_ANNOTATION_ATTR", "HLSLAnnotationAttr"}
 };
@@ -4328,10 +4329,12 @@ static void GenerateMutualExclusionsChecks(const Record &Attr,
 
   // This means the attribute is either a statement attribute, a decl
   // attribute, or both; find out which.
-  bool CurAttrIsStmtAttr =
-      Attr.isSubClassOf("StmtAttr") || Attr.isSubClassOf("DeclOrStmtAttr");
-  bool CurAttrIsDeclAttr =
-      !CurAttrIsStmtAttr || Attr.isSubClassOf("DeclOrStmtAttr");
+  bool CurAttrIsStmtAttr = Attr.isSubClassOf("StmtAttr") ||
+                           Attr.isSubClassOf("DeclOrStmtAttr") ||
+                           Attr.isSubClassOf("InheritableParamOrStmtAttr");
+  bool CurAttrIsDeclAttr = !CurAttrIsStmtAttr ||
+                           Attr.isSubClassOf("DeclOrStmtAttr") ||
+                           Attr.isSubClassOf("InheritableParamOrStmtAttr");
 
   std::vector<std::string> DeclAttrs, StmtAttrs;