mboehme created this revision.
mboehme added a project: clang.
Herald added a reviewer: aaron.ballman.
mboehme requested review of this revision.
Herald added a subscriber: cfe-commits.
This is an analog to the `annotate` attribute but for types. The intent is to
allow adding arbitrary annotations to types for use in static analysis tools.
DO NOT REVIEW YET
I'm uploading this for discussion on cfe-dev. Will remove this note once the
change is ready for review.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D111548
Files:
clang/include/clang/Basic/Attr.td
clang/include/clang/Sema/Sema.h
clang/lib/AST/TypePrinter.cpp
clang/lib/Sema/SemaAttr.cpp
clang/lib/Sema/SemaDeclAttr.cpp
clang/lib/Sema/SemaType.cpp
clang/test/Sema/annotate-type.c
Index: clang/test/Sema/annotate-type.c
===================================================================
--- /dev/null
+++ clang/test/Sema/annotate-type.c
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 %s -fsyntax-only -fdouble-square-bracket-attributes -verify
+
+void foo(float *__attribute__((annotate_type("foo"))) a) {
+ // Only the GNU spelling of the attribute can be applied to decl specifiers.
+ int __attribute__((annotate_type("bar"))) w;
+ int [[clang::annotate_type("bar")]] w2; // expected-error {{'annotate_type' attribute cannot be applied to types}}
+
+ int *__attribute__((annotate_type("bar"))) x;
+ int *[[clang::annotate_type("bar")]] x2;
+
+ int *__attribute__((annotate_type(1))) y; // expected-error {{'annotate_type' attribute requires a string}}
+ int *[[clang::annotate_type(1)]] y2; // expected-error {{'annotate_type' attribute requires a string}}
+
+ int *__attribute__((annotate_type("bar", 1))) z;
+ int *[[clang::annotate_type("bar", 1)]] z2;
+}
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -8036,6 +8036,30 @@
CurType = T;
}
+static void HandleAnnotateTypeAttr(TypeProcessingState &State,
+ QualType &CurType, const ParsedAttr &Attr) {
+ Sema &S = State.getSema();
+
+ // Make sure that there is a string literal as the annotation's first
+ // argument.
+ StringRef Str;
+ if (!S.checkStringLiteralArgumentAttr(Attr, 0, Str))
+ return;
+
+ llvm::SmallVector<Expr *, 4> Args;
+ Args.reserve(Attr.getNumArgs() - 1);
+ for (unsigned Idx = 1; Idx < Attr.getNumArgs(); Idx++) {
+ assert(!Attr.isArgIdent(Idx));
+ Args.push_back(Attr.getArgAsExpr(Idx));
+ }
+ if (!S.ConstantFoldAttrArgs(Attr, Args)) {
+ return;
+ }
+ auto *AnnotateTypeAttr =
+ AnnotateTypeAttr::Create(S.Context, Str, Args.data(), Args.size(), Attr);
+ CurType = State.getAttributedType(AnnotateTypeAttr, CurType, CurType);
+}
+
static void HandleLifetimeBoundAttr(TypeProcessingState &State,
QualType &CurType,
ParsedAttr &Attr) {
@@ -8298,6 +8322,11 @@
attr.setUsedAsTypeAttr();
break;
}
+ case ParsedAttr::AT_AnnotateType: {
+ HandleAnnotateTypeAttr(state, type, attr);
+ attr.setUsedAsTypeAttr();
+ break;
+ }
}
// Handle attributes that are defined in a macro. We do not want this to be
Index: clang/lib/Sema/SemaDeclAttr.cpp
===================================================================
--- clang/lib/Sema/SemaDeclAttr.cpp
+++ clang/lib/Sema/SemaDeclAttr.cpp
@@ -3863,48 +3863,10 @@
void Sema::AddAnnotationAttr(Decl *D, const AttributeCommonInfo &CI,
StringRef Str, MutableArrayRef<Expr *> Args) {
auto *Attr = AnnotateAttr::Create(Context, Str, Args.data(), Args.size(), CI);
- llvm::SmallVector<PartialDiagnosticAt, 8> Notes;
- for (unsigned Idx = 0; Idx < Attr->args_size(); Idx++) {
- Expr *&E = Attr->args_begin()[Idx];
- assert(E && "error are handled before");
- if (E->isValueDependent() || E->isTypeDependent())
- continue;
-
- if (E->getType()->isArrayType())
- E = ImpCastExprToType(E, Context.getPointerType(E->getType()),
- clang::CK_ArrayToPointerDecay)
- .get();
- if (E->getType()->isFunctionType())
- E = ImplicitCastExpr::Create(Context,
- Context.getPointerType(E->getType()),
- clang::CK_FunctionToPointerDecay, E, nullptr,
- VK_PRValue, FPOptionsOverride());
- if (E->isLValue())
- E = ImplicitCastExpr::Create(Context, E->getType().getNonReferenceType(),
- clang::CK_LValueToRValue, E, nullptr,
- VK_PRValue, FPOptionsOverride());
-
- Expr::EvalResult Eval;
- Notes.clear();
- Eval.Diag = &Notes;
-
- bool Result =
- E->EvaluateAsConstantExpr(Eval, Context);
-
- /// Result means the expression can be folded to a constant.
- /// Note.empty() means the expression is a valid constant expression in the
- /// current language mode.
- if (!Result || !Notes.empty()) {
- Diag(E->getBeginLoc(), diag::err_attribute_argument_n_type)
- << CI << (Idx + 1) << AANT_ArgumentConstantExpr;
- for (auto &Note : Notes)
- Diag(Note.first, Note.second);
- return;
- }
- assert(Eval.Val.hasValue());
- E = ConstantExpr::Create(Context, E, Eval.Val);
+ if (ConstantFoldAttrArgs(
+ CI, MutableArrayRef<Expr *>(Attr->args_begin(), Attr->args_end()))) {
+ D->addAttr(Attr);
}
- D->addAttr(Attr);
}
static void handleAnnotateAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
Index: clang/lib/Sema/SemaAttr.cpp
===================================================================
--- clang/lib/Sema/SemaAttr.cpp
+++ clang/lib/Sema/SemaAttr.cpp
@@ -384,6 +384,52 @@
AlignPackStack.Act(PragmaLoc, Action, SlotLabel, Info);
}
+bool Sema::ConstantFoldAttrArgs(const AttributeCommonInfo &CI,
+ MutableArrayRef<Expr *> Args) {
+ llvm::SmallVector<PartialDiagnosticAt, 8> Notes;
+ for (unsigned Idx = 0; Idx < Args.size(); Idx++) {
+ Expr *&E = Args.begin()[Idx];
+ assert(E && "error are handled before");
+ if (E->isValueDependent() || E->isTypeDependent())
+ continue;
+
+ if (E->getType()->isArrayType())
+ E = ImpCastExprToType(E, Context.getPointerType(E->getType()),
+ clang::CK_ArrayToPointerDecay)
+ .get();
+ if (E->getType()->isFunctionType())
+ E = ImplicitCastExpr::Create(Context,
+ Context.getPointerType(E->getType()),
+ clang::CK_FunctionToPointerDecay, E, nullptr,
+ VK_PRValue, FPOptionsOverride());
+ if (E->isLValue())
+ E = ImplicitCastExpr::Create(Context, E->getType().getNonReferenceType(),
+ clang::CK_LValueToRValue, E, nullptr,
+ VK_PRValue, FPOptionsOverride());
+
+ Expr::EvalResult Eval;
+ Notes.clear();
+ Eval.Diag = &Notes;
+
+ bool Result = E->EvaluateAsConstantExpr(Eval, Context);
+
+ /// Result means the expression can be folded to a constant.
+ /// Note.empty() means the expression is a valid constant expression in the
+ /// current language mode.
+ if (!Result || !Notes.empty()) {
+ Diag(E->getBeginLoc(), diag::err_attribute_argument_n_type)
+ << CI << (Idx + 1) << AANT_ArgumentConstantExpr;
+ for (auto &Note : Notes)
+ Diag(Note.first, Note.second);
+ return false;
+ }
+ assert(Eval.Val.hasValue());
+ E = ConstantExpr::Create(Context, E, Eval.Val);
+ }
+
+ return true;
+}
+
void Sema::DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
SourceLocation IncludeLoc) {
if (Kind == PragmaAlignPackDiagnoseKind::NonDefaultStateAtInclude) {
Index: clang/lib/AST/TypePrinter.cpp
===================================================================
--- clang/lib/AST/TypePrinter.cpp
+++ clang/lib/AST/TypePrinter.cpp
@@ -1670,6 +1670,11 @@
if (T->getAttrKind() == attr::AddressSpace)
return;
+ // We have no way to meaningfully print annotate_type attributes because that
+ // would require retrieving the attribute arguments, which we don't have here.
+ if (T->getAttrKind() == attr::AnnotateType)
+ return;
+
OS << " __attribute__((";
switch (T->getAttrKind()) {
#define TYPE_ATTR(NAME)
@@ -1705,6 +1710,7 @@
case attr::AddressSpace:
case attr::CmseNSCall:
case attr::BTFTag:
+ case attr::AnnotateType:
llvm_unreachable("This attribute should have been handled already");
case attr::NSReturnsRetained:
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -10217,6 +10217,13 @@
void AddAnnotationAttr(Decl *D, const AttributeCommonInfo &CI,
StringRef Annot, MutableArrayRef<Expr *> Args);
+ /// ConstantFoldAttrArgs - Folds attribute arguments into ConstantExprs
+ /// (unless they are value dependent or type dependent). Returns false
+ /// and emits a diagnostic if one or more of the arguments could not be
+ /// folded into a constant.
+ bool ConstantFoldAttrArgs(const AttributeCommonInfo &CI,
+ MutableArrayRef<Expr *> Args);
+
/// AddLaunchBoundsAttr - Adds a launch_bounds attribute to a particular
/// declaration.
void AddLaunchBoundsAttr(Decl *D, const AttributeCommonInfo &CI,
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -787,6 +787,12 @@
let Documentation = [Undocumented];
}
+def AnnotateType : TypeAttr {
+ let Spellings = [Clang<"annotate_type">];
+ let Args = [StringArgument<"Annotation">, VariadicExprArgument<"Args">];
+ let Documentation = [Undocumented];
+}
+
def ARMInterrupt : InheritableAttr, TargetSpecificAttr<TargetARM> {
// NOTE: If you add any additional spellings, M68kInterrupt's,
// MSP430Interrupt's, MipsInterrupt's and AnyX86Interrupt's spellings
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