[clang] [BoundsSafety] Allow 'counted_by' attribute on pointers in structs in C (PR #90786)
Dan Liew via cfe-commits
cfe-commits at lists.llvm.org
Fri May 3 13:27:08 PDT 2024
https://github.com/delcypher updated https://github.com/llvm/llvm-project/pull/90786
>From 1f4d924768409d6bc61d160c6161e6acebf62b60 Mon Sep 17 00:00:00 2001
From: Dan Liew <dan at su-root.co.uk>
Date: Wed, 1 May 2024 13:56:52 -0700
Subject: [PATCH 1/3] [BoundsSafety] Allow 'counted_by' attribute on pointers
in structs in C
Previously the attribute was only allowed on flexible array members.
This patch patch changes this to also allow the attribute on pointer
fields in structs and also allows late parsing of the attribute in some
contexts.
For example this previously wasn't allowed:
```
struct BufferTypeDeclAttributePosition {
size_t count;
char* buffer __counted_by(count); // Now allowed
}
```
Note the attribute is prevented on pointee types where the size isn't
known at compile time. In particular pointee types that are:
* Incomplete (e.g. `void`) and sizeless types
* Function types (e.g. the pointee of a function pointer)
* Struct types with a flexible array member
This patch also introduces late parsing of the attribute when used
in the declaration attribute position. For example
```
struct BufferTypeDeclAttributePosition {
char* buffer __counted_by(count); // Now allowed
size_t count;
}
```
is now allowed but **only** when passing
`-fexperimental-late-parse-attributes`. The motivation for using late
parsing here is to avoid breaking the data layout of structs in existing
code that want to use the `counted_by` attribute. This patch is the
first use of `LateAttrParseExperimentalExt` in `Attr.td` that was
introduced in a previous patch.
Note by allowing the attribute on struct member pointers this now allows
the possiblity of writing the attribute in the type attribute position.
For example:
```
struct BufferTypeAttributePosition {
size_t count;
char *__counted_by(count) buffer; // Now allowed
}
```
However, the attribute in this position is still currently parsed
immediately rather than late parsed. So this will not parse currently:
```
struct BufferTypeAttributePosition {
char *__counted_by(count) buffer; // Fails to parse
size_t count;
}
```
The intention is to lift this restriction in future patches. It has not
been done in this patch to keep this size of this commit small.
There are also several other follow up changes that will need to be
addressed in future patches:
* Make late parsing working with anonymous structs (see
`on_pointer_anon_buf` in `attr-counted-by-late-parsed-struct-ptrs.c`).
* Allow `counted_by` on more subjedts (e.g. parameters, returns types)
when `-fbounds-safety` is enabled.
* Make use of the attribute on pointer types in code gen (e.g.
for `_builtin_dynamic_object_size` and UBSan's array-bounds checks).
This work is heavily based on a patch originally written by Yeoul Na.
rdar://125400257
---
clang/docs/ReleaseNotes.rst | 19 +-
clang/include/clang/AST/Type.h | 1 +
clang/include/clang/Basic/Attr.td | 3 +-
.../clang/Basic/DiagnosticSemaKinds.td | 15 +-
clang/include/clang/Parse/Parser.h | 7 +-
clang/include/clang/Sema/Sema.h | 3 +-
clang/lib/AST/Type.cpp | 12 ++
clang/lib/Parse/ParseDecl.cpp | 104 +++++++++-
clang/lib/Parse/ParseObjc.cpp | 10 +-
clang/lib/Sema/SemaDeclAttr.cpp | 71 +++++--
clang/lib/Sema/SemaType.cpp | 6 +-
clang/lib/Sema/TreeTransform.h | 2 +-
.../attr-counted-by-late-parsed-struct-ptrs.c | 45 ++++
clang/test/AST/attr-counted-by-struct-ptrs.c | 117 +++++++++++
.../Sema/attr-counted-by-late-parsed-off.c | 26 +++
.../attr-counted-by-late-parsed-struct-ptrs.c | 192 ++++++++++++++++++
...tr-counted-by-struct-ptrs-sizeless-types.c | 17 ++
clang/test/Sema/attr-counted-by-struct-ptrs.c | 170 ++++++++++++++++
clang/test/Sema/attr-counted-by.c | 5 +-
19 files changed, 787 insertions(+), 38 deletions(-)
create mode 100644 clang/test/AST/attr-counted-by-late-parsed-struct-ptrs.c
create mode 100644 clang/test/AST/attr-counted-by-struct-ptrs.c
create mode 100644 clang/test/Sema/attr-counted-by-late-parsed-off.c
create mode 100644 clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c
create mode 100644 clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c
create mode 100644 clang/test/Sema/attr-counted-by-struct-ptrs.c
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 4c0fe5bcf6b122..81d0a89b294878 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -258,7 +258,8 @@ New Compiler Flags
- ``-fexperimental-late-parse-attributes`` enables an experimental feature to
allow late parsing certain attributes in specific contexts where they would
- not normally be late parsed.
+ not normally be late parsed. Currently this allows late parsing the
+ `counted_by` attribute in C. See `Attribute Changes in Clang`_.
Deprecated Compiler Flags
-------------------------
@@ -335,6 +336,22 @@ Attribute Changes in Clang
- Clang now warns that the ``exclude_from_explicit_instantiation`` attribute
is ignored when applied to a local class or a member thereof.
+- The ``counted_by`` attribute can now be late parsed in C when
+ ``-fexperimental-late-parse-attributes`` is passed but only when attribute is
+ used in the declaration attribute position. This allows using the
+ attribute on existing code where it previously impossible to do so without
+ re-ordering struct field declarations would break ABI as shown below.
+
+ .. code-block:: c
+
+ struct BufferTy {
+ /* Refering to `count` requires late parsing */
+ char* buffer __counted_by(count);
+ /* Swapping `buffer` and `count` to avoid late parsing would break ABI */
+ size_t count;
+ };
+
+
Improvements to Clang's diagnostics
-----------------------------------
- Clang now applies syntax highlighting to the code snippets it
diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
index e6643469e0b334..e982a565413751 100644
--- a/clang/include/clang/AST/Type.h
+++ b/clang/include/clang/AST/Type.h
@@ -2515,6 +2515,7 @@ class alignas(TypeAlignment) Type : public ExtQualsTypeCommonBase {
bool isRecordType() const;
bool isClassType() const;
bool isStructureType() const;
+ bool isStructureTypeWithFlexibleArrayMember() const;
bool isObjCBoxableRecordType() const;
bool isInterfaceType() const;
bool isStructureOrClassType() const;
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 0225598cbbe8ad..ef08d2a274a907 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2229,7 +2229,8 @@ def TypeNullUnspecified : TypeAttr {
def CountedBy : DeclOrTypeAttr {
let Spellings = [Clang<"counted_by">];
let Subjects = SubjectList<[Field], ErrorDiag>;
- let Args = [ExprArgument<"Count">, IntArgument<"NestedLevel">];
+ let Args = [ExprArgument<"Count">, IntArgument<"NestedLevel", 1>];
+ let LateParsed = LateAttrParseExperimentalExt;
let ParseArgumentsAsUnevaluated = 1;
let Documentation = [CountedByDocs];
let LangOpts = [COnly];
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index f72d5c252b863e..0ab2a96c7b464b 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6518,8 +6518,10 @@ def warn_superclass_variable_sized_type_not_at_end : Warning<
def err_flexible_array_count_not_in_same_struct : Error<
"'counted_by' field %0 isn't within the same struct as the flexible array">;
-def err_counted_by_attr_not_on_flexible_array_member : Error<
- "'counted_by' only applies to C99 flexible array members">;
+def err_counted_by_attr_not_on_ptr_or_flexible_array_member : Error<
+ "'counted_by' only applies to pointers or C99 flexible array members">;
+def err_counted_by_attr_on_array_not_flexible_array_member : Error<
+ "'counted_by' on arrays only applies to C99 flexible array members">;
def err_counted_by_attr_refer_to_itself : Error<
"'counted_by' cannot refer to the flexible array member %0">;
def err_counted_by_must_be_in_structure : Error<
@@ -6534,6 +6536,15 @@ def err_counted_by_attr_refer_to_union : Error<
"'counted_by' argument cannot refer to a union member">;
def note_flexible_array_counted_by_attr_field : Note<
"field %0 declared here">;
+def err_counted_by_attr_pointee_unknown_size : Error<
+ "'counted_by' cannot be applied a pointer with pointee with unknown size "
+ "because %0 is %select{"
+ "an incomplete type|" // CountedByInvalidPointeeTypeKind::INCOMPLETE
+ "a sizeless type|" // CountedByInvalidPointeeTypeKind::SIZELESS
+ "a function type|" // CountedByInvalidPointeeTypeKind::FUNCTION
+ // CountedByInvalidPointeeTypeKind::FLEXIBLE_ARRAY_MEMBER
+ "a struct type with a flexible array member"
+ "}1">;
let CategoryName = "ARC Semantic Issue" in {
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 81aab8c888ab65..0f2ba17aadaf2d 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -1643,6 +1643,8 @@ class Parser : public CodeCompletionHandler {
bool EnterScope, bool OnDefinition);
void ParseLexedAttribute(LateParsedAttribute &LA,
bool EnterScope, bool OnDefinition);
+ void ParseLexedCAttribute(LateParsedAttribute &LA,
+ ParsedAttributes *OutAttrs = nullptr);
void ParseLexedMethodDeclarations(ParsingClass &Class);
void ParseLexedMethodDeclaration(LateParsedMethodDeclaration &LM);
void ParseLexedMethodDefs(ParsingClass &Class);
@@ -2530,7 +2532,8 @@ class Parser : public CodeCompletionHandler {
void ParseStructDeclaration(
ParsingDeclSpec &DS,
- llvm::function_ref<void(ParsingFieldDeclarator &)> FieldsCallback);
+ llvm::function_ref<Decl *(ParsingFieldDeclarator &)> FieldsCallback,
+ LateParsedAttrList *LateFieldAttrs = nullptr);
DeclGroupPtrTy ParseTopLevelStmtDecl();
@@ -3107,6 +3110,8 @@ class Parser : public CodeCompletionHandler {
SourceLocation ScopeLoc,
ParsedAttr::Form Form);
+ void DistributeCLateParsedAttrs(Decl *Dcl, LateParsedAttrList *LateAttrs);
+
void ParseBoundsAttribute(IdentifierInfo &AttrName,
SourceLocation AttrNameLoc, ParsedAttributes &Attrs,
IdentifierInfo *ScopeName, SourceLocation ScopeLoc,
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 1ca523ec88c2f9..f1e1be24f4fd2f 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -11509,7 +11509,8 @@ class Sema final : public SemaBase {
QualType BuildMatrixType(QualType T, Expr *NumRows, Expr *NumColumns,
SourceLocation AttrLoc);
- QualType BuildCountAttributedArrayType(QualType WrappedTy, Expr *CountExpr);
+ QualType BuildCountAttributedArrayOrPointerType(QualType WrappedTy,
+ Expr *CountExpr);
QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
SourceLocation AttrLoc);
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index 68e81f45b4c28e..316d70e0b79ecf 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -631,6 +631,18 @@ bool Type::isStructureType() const {
return false;
}
+bool Type::isStructureTypeWithFlexibleArrayMember() const {
+ const auto *RT = getAs<RecordType>();
+ if (!RT)
+ return false;
+ const auto *Decl = RT->getDecl();
+ if (!Decl->isStruct())
+ return false;
+ if (!Decl->hasFlexibleArrayMember())
+ return false;
+ return true;
+}
+
bool Type::isObjCBoxableRecordType() const {
if (const auto *RT = getAs<RecordType>())
return RT->getDecl()->hasAttr<ObjCBoxableAttr>();
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 7431c256d2c135..470d26fb3d73be 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3282,6 +3282,19 @@ void Parser::ParseAlignmentSpecifier(ParsedAttributes &Attrs,
}
}
+void Parser::DistributeCLateParsedAttrs(Decl *Dcl,
+ LateParsedAttrList *LateAttrs) {
+ assert(Dcl);
+
+ if (!LateAttrs)
+ return;
+
+ for (auto *LateAttr : *LateAttrs) {
+ if (LateAttr->Decls.empty())
+ LateAttr->addDecl(Dcl);
+ }
+}
+
/// Bounds attributes (e.g., counted_by):
/// AttrName '(' expression ')'
void Parser::ParseBoundsAttribute(IdentifierInfo &AttrName,
@@ -4815,13 +4828,14 @@ static void DiagnoseCountAttributedTypeInUnnamedAnon(ParsingDeclSpec &DS,
///
void Parser::ParseStructDeclaration(
ParsingDeclSpec &DS,
- llvm::function_ref<void(ParsingFieldDeclarator &)> FieldsCallback) {
+ llvm::function_ref<Decl *(ParsingFieldDeclarator &)> FieldsCallback,
+ LateParsedAttrList *LateFieldAttrs) {
if (Tok.is(tok::kw___extension__)) {
// __extension__ silences extension warnings in the subexpression.
ExtensionRAIIObject O(Diags); // Use RAII to do this.
ConsumeToken();
- return ParseStructDeclaration(DS, FieldsCallback);
+ return ParseStructDeclaration(DS, FieldsCallback, LateFieldAttrs);
}
// Parse leading attributes.
@@ -4886,10 +4900,12 @@ void Parser::ParseStructDeclaration(
}
// If attributes exist after the declarator, parse them.
- MaybeParseGNUAttributes(DeclaratorInfo.D);
+ MaybeParseGNUAttributes(DeclaratorInfo.D, LateFieldAttrs);
// We're done with this declarator; invoke the callback.
- FieldsCallback(DeclaratorInfo);
+ Decl *Field = FieldsCallback(DeclaratorInfo);
+ if (Field)
+ DistributeCLateParsedAttrs(Field, LateFieldAttrs);
// If we don't have a comma, it is either the end of the list (a ';')
// or an error, bail out.
@@ -4900,6 +4916,69 @@ void Parser::ParseStructDeclaration(
}
}
+/// Finish parsing an attribute for which parsing was delayed.
+/// This will be called at the end of parsing a class declaration
+/// for each LateParsedAttribute. We consume the saved tokens and
+/// create an attribute with the arguments filled in. We add this
+/// to the Attribute list for the decl.
+void Parser::ParseLexedCAttribute(LateParsedAttribute &LA,
+ ParsedAttributes *OutAttrs) {
+ // Create a fake EOF so that attribute parsing won't go off the end of the
+ // attribute.
+ Token AttrEnd;
+ AttrEnd.startToken();
+ AttrEnd.setKind(tok::eof);
+ AttrEnd.setLocation(Tok.getLocation());
+ AttrEnd.setEofData(LA.Toks.data());
+ LA.Toks.push_back(AttrEnd);
+
+ // Append the current token at the end of the new token stream so that it
+ // doesn't get lost.
+ LA.Toks.push_back(Tok);
+ PP.EnterTokenStream(LA.Toks, /*DisableMacroExpansion=*/true,
+ /*IsReinject=*/true);
+ // Drop the current token and bring the first cached one. It's the same token
+ // as when we entered this function.
+ ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
+
+ ParsedAttributes Attrs(AttrFactory);
+
+ assert(LA.Decls.size() <= 1 &&
+ "late field attribute expects to have at most one declaration.");
+
+ // Dispatch based on the attribute and parse it
+ const AttributeCommonInfo::Form ParsedForm = ParsedAttr::Form::GNU();
+ IdentifierInfo *ScopeName = nullptr;
+ const ParsedAttr::Kind AttrKind =
+ ParsedAttr::getParsedKind(&LA.AttrName, /*ScopeName=*/ScopeName,
+ /*SyntaxUsed=*/ParsedForm.getSyntax());
+ switch (AttrKind) {
+ case ParsedAttr::Kind::AT_CountedBy:
+ ParseBoundsAttribute(LA.AttrName, LA.AttrNameLoc, Attrs,
+ /*ScopeName=*/ScopeName, SourceLocation(),
+ /*Form=*/ParsedForm);
+ break;
+ default:
+ llvm_unreachable("Unhandled late parsed attribute");
+ }
+
+ for (auto *D : LA.Decls)
+ Actions.ActOnFinishDelayedAttribute(getCurScope(), D, Attrs);
+
+ // Due to a parsing error, we either went over the cached tokens or
+ // there are still cached tokens left, so we skip the leftover tokens.
+ while (Tok.isNot(tok::eof))
+ ConsumeAnyToken();
+
+ // Consume the fake EOF token if it's there
+ if (Tok.is(tok::eof) && Tok.getEofData() == AttrEnd.getEofData())
+ ConsumeAnyToken();
+
+ if (OutAttrs) {
+ OutAttrs->takeAllFrom(Attrs);
+ }
+}
+
/// ParseStructUnionBody
/// struct-contents:
/// struct-declaration-list
@@ -4923,6 +5002,11 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
ParseScope StructScope(this, Scope::ClassScope|Scope::DeclScope);
Actions.ActOnTagStartDefinition(getCurScope(), TagDecl);
+ // `LateAttrParseExperimentalExtOnly=true` requests that only attributes
+ // marked with `LateAttrParseExperimentalExt` are late parsed.
+ LateParsedAttrList LateFieldAttrs(/*PSoon=*/false,
+ /*LateAttrParseExperimentalExtOnly=*/true);
+
// While we still have something to read, read the declarations in the struct.
while (!tryParseMisplacedModuleImport() && Tok.isNot(tok::r_brace) &&
Tok.isNot(tok::eof)) {
@@ -4973,18 +5057,19 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
}
if (!Tok.is(tok::at)) {
- auto CFieldCallback = [&](ParsingFieldDeclarator &FD) {
+ auto CFieldCallback = [&](ParsingFieldDeclarator &FD) -> Decl * {
// Install the declarator into the current TagDecl.
Decl *Field =
Actions.ActOnField(getCurScope(), TagDecl,
FD.D.getDeclSpec().getSourceRange().getBegin(),
FD.D, FD.BitfieldSize);
FD.complete(Field);
+ return Field;
};
// Parse all the comma separated declarators.
ParsingDeclSpec DS(*this);
- ParseStructDeclaration(DS, CFieldCallback);
+ ParseStructDeclaration(DS, CFieldCallback, &LateFieldAttrs);
} else { // Handle @defs
ConsumeToken();
if (!Tok.isObjCAtKeyword(tok::objc_defs)) {
@@ -5025,7 +5110,12 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
ParsedAttributes attrs(AttrFactory);
// If attributes exist after struct contents, parse them.
- MaybeParseGNUAttributes(attrs);
+ MaybeParseGNUAttributes(attrs, &LateFieldAttrs);
+
+ // Late parse field attributes if necessary.
+ assert(!getLangOpts().CPlusPlus);
+ for (auto *LateAttr : LateFieldAttrs)
+ ParseLexedCAttribute(*LateAttr);
SmallVector<Decl *, 32> FieldDecls(TagDecl->fields());
diff --git a/clang/lib/Parse/ParseObjc.cpp b/clang/lib/Parse/ParseObjc.cpp
index 8e54fe012c55d7..2eaeff38a24a6f 100644
--- a/clang/lib/Parse/ParseObjc.cpp
+++ b/clang/lib/Parse/ParseObjc.cpp
@@ -778,16 +778,16 @@ void Parser::ParseObjCInterfaceDeclList(tok::ObjCKeywordKind contextKey,
}
bool addedToDeclSpec = false;
- auto ObjCPropertyCallback = [&](ParsingFieldDeclarator &FD) {
+ auto ObjCPropertyCallback = [&](ParsingFieldDeclarator &FD) -> Decl * {
if (FD.D.getIdentifier() == nullptr) {
Diag(AtLoc, diag::err_objc_property_requires_field_name)
<< FD.D.getSourceRange();
- return;
+ return nullptr;
}
if (FD.BitfieldSize) {
Diag(AtLoc, diag::err_objc_property_bitfield)
<< FD.D.getSourceRange();
- return;
+ return nullptr;
}
// Map a nullability property attribute to a context-sensitive keyword
@@ -816,6 +816,7 @@ void Parser::ParseObjCInterfaceDeclList(tok::ObjCKeywordKind contextKey,
MethodImplKind);
FD.complete(Property);
+ return Property;
};
// Parse all the comma separated declarators.
@@ -2024,7 +2025,7 @@ void Parser::ParseObjCClassInstanceVariables(ObjCContainerDecl *interfaceDecl,
continue;
}
- auto ObjCIvarCallback = [&](ParsingFieldDeclarator &FD) {
+ auto ObjCIvarCallback = [&](ParsingFieldDeclarator &FD) -> Decl * {
assert(getObjCDeclContext() == interfaceDecl &&
"Ivar should have interfaceDecl as its decl context");
// Install the declarator into the interface decl.
@@ -2035,6 +2036,7 @@ void Parser::ParseObjCClassInstanceVariables(ObjCContainerDecl *interfaceDecl,
if (Field)
AllIvarDecls.push_back(Field);
FD.complete(Field);
+ return Field;
};
// Parse all the comma separated declarators.
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 363ae93cb62df1..7ae1e09c7a5dcd 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -8588,31 +8588,71 @@ static const RecordDecl *GetEnclosingNamedOrTopAnonRecord(const FieldDecl *FD) {
return RD;
}
-static bool
-CheckCountExpr(Sema &S, FieldDecl *FD, Expr *E,
- llvm::SmallVectorImpl<TypeCoupledDeclRefInfo> &Decls) {
+enum class CountedByInvalidPointeeTypeKind {
+ INCOMPLETE,
+ SIZELESS,
+ FUNCTION,
+ FLEXIBLE_ARRAY_MEMBER,
+ VALID,
+};
+
+static bool CheckCountedByAttrOnField(
+ Sema &S, FieldDecl *FD, Expr *E,
+ llvm::SmallVectorImpl<TypeCoupledDeclRefInfo> &Decls) {
+ // Check the context the attribute is used in
+
if (FD->getParent()->isUnion()) {
S.Diag(FD->getBeginLoc(), diag::err_counted_by_attr_in_union)
<< FD->getSourceRange();
return true;
}
- if (!E->getType()->isIntegerType() || E->getType()->isBooleanType()) {
- S.Diag(E->getBeginLoc(), diag::err_counted_by_attr_argument_not_integer)
- << E->getSourceRange();
+ const auto FieldTy = FD->getType();
+ if (!FieldTy->isArrayType() && !FieldTy->isPointerType()) {
+ S.Diag(FD->getBeginLoc(),
+ diag::err_counted_by_attr_not_on_ptr_or_flexible_array_member)
+ << FD->getLocation();
return true;
}
LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel =
LangOptions::StrictFlexArraysLevelKind::IncompleteOnly;
-
- if (!Decl::isFlexibleArrayMemberLike(S.getASTContext(), FD, FD->getType(),
+ if (FieldTy->isArrayType() &&
+ !Decl::isFlexibleArrayMemberLike(S.getASTContext(), FD, FieldTy,
StrictFlexArraysLevel, true)) {
- // The "counted_by" attribute must be on a flexible array member.
- SourceRange SR = FD->getLocation();
- S.Diag(SR.getBegin(),
- diag::err_counted_by_attr_not_on_flexible_array_member)
- << SR;
+ S.Diag(FD->getBeginLoc(),
+ diag::err_counted_by_attr_on_array_not_flexible_array_member)
+ << FD->getLocation();
+ return true;
+ }
+
+ if (FieldTy->isPointerType()) {
+ CountedByInvalidPointeeTypeKind InvalidTypeKind =
+ CountedByInvalidPointeeTypeKind::VALID;
+ const auto PointeeTy = FieldTy->getPointeeType();
+ if (PointeeTy->isIncompleteType()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::INCOMPLETE;
+ } else if (PointeeTy->isSizelessType()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::SIZELESS;
+ } else if (PointeeTy->isFunctionType()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::FUNCTION;
+ } else if (PointeeTy->isStructureTypeWithFlexibleArrayMember()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::FLEXIBLE_ARRAY_MEMBER;
+ }
+
+ if (InvalidTypeKind != CountedByInvalidPointeeTypeKind::VALID) {
+ S.Diag(FD->getBeginLoc(), diag::err_counted_by_attr_pointee_unknown_size)
+ << FieldTy->getPointeeType() << (int)InvalidTypeKind
+ << FD->getSourceRange();
+ return true;
+ }
+ }
+
+ // Check the expression
+
+ if (!E->getType()->isIntegerType() || E->getType()->isBooleanType()) {
+ S.Diag(E->getBeginLoc(), diag::err_counted_by_attr_argument_not_integer)
+ << E->getSourceRange();
return true;
}
@@ -8675,10 +8715,11 @@ static void handleCountedByAttrField(Sema &S, Decl *D, const ParsedAttr &AL) {
return;
llvm::SmallVector<TypeCoupledDeclRefInfo, 1> Decls;
- if (CheckCountExpr(S, FD, CountExpr, Decls))
+ if (CheckCountedByAttrOnField(S, FD, CountExpr, Decls))
return;
- QualType CAT = S.BuildCountAttributedArrayType(FD->getType(), CountExpr);
+ QualType CAT =
+ S.BuildCountAttributedArrayOrPointerType(FD->getType(), CountExpr);
FD->setType(CAT);
}
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index fddc3545ecb61c..29e9700959cf51 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -9790,9 +9790,9 @@ BuildTypeCoupledDecls(Expr *E,
Decls.push_back(TypeCoupledDeclRefInfo(CountDecl, /*IsDref*/ false));
}
-QualType Sema::BuildCountAttributedArrayType(QualType WrappedTy,
- Expr *CountExpr) {
- assert(WrappedTy->isIncompleteArrayType());
+QualType Sema::BuildCountAttributedArrayOrPointerType(QualType WrappedTy,
+ Expr *CountExpr) {
+ assert(WrappedTy->isIncompleteArrayType() || WrappedTy->isPointerType());
llvm::SmallVector<TypeCoupledDeclRefInfo, 1> Decls;
BuildTypeCoupledDecls(CountExpr, Decls);
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index f47bc219e6fa32..7c37066e6b6152 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -7337,7 +7337,7 @@ QualType TreeTransform<Derived>::TransformCountAttributedType(
if (getDerived().AlwaysRebuild() || InnerTy != OldTy->desugar() ||
OldCount != NewCount) {
// Currently, CountAttributedType can only wrap incomplete array types.
- Result = SemaRef.BuildCountAttributedArrayType(InnerTy, NewCount);
+ Result = SemaRef.BuildCountAttributedArrayOrPointerType(InnerTy, NewCount);
}
TLB.push<CountAttributedTypeLoc>(Result);
diff --git a/clang/test/AST/attr-counted-by-late-parsed-struct-ptrs.c b/clang/test/AST/attr-counted-by-late-parsed-struct-ptrs.c
new file mode 100644
index 00000000000000..a585a45eeff03d
--- /dev/null
+++ b/clang/test/AST/attr-counted-by-late-parsed-struct-ptrs.c
@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -fexperimental-late-parse-attributes %s -ast-dump | FileCheck %s
+
+#define __counted_by(f) __attribute__((counted_by(f)))
+
+struct size_known {
+ int field;
+};
+
+//==============================================================================
+// __counted_by on struct member pointer in decl attribute position
+//==============================================================================
+
+struct on_member_pointer_complete_ty {
+ struct size_known *buf __counted_by(count);
+ int count;
+};
+// CHECK-LABEL: struct on_member_pointer_complete_ty definition
+// CHECK-NEXT: |-FieldDecl {{.*}} buf 'struct size_known * __counted_by(count)':'struct size_known *'
+// CHECK-NEXT: `-FieldDecl {{.*}} referenced count 'int'
+
+struct on_pointer_anon_count {
+ struct size_known *buf __counted_by(count);
+ struct {
+ int count;
+ };
+};
+
+// CHECK-LABEL: struct on_pointer_anon_count definition
+// CHECK-NEXT: |-FieldDecl {{.*}} buf 'struct size_known * __counted_by(count)':'struct size_known *'
+// CHECK-NEXT: |-RecordDecl {{.*}} struct definition
+// CHECK-NEXT: | `-FieldDecl {{.*}} count 'int'
+// CHECK-NEXT: |-FieldDecl {{.*}} implicit 'struct on_pointer_anon_count::(anonymous at {{.*}})'
+// CHECK-NEXT: `-IndirectFieldDecl {{.*}} implicit referenced count 'int'
+// CHECK-NEXT: |-Field {{.*}} '' 'struct on_pointer_anon_count::(anonymous at {{.*}})'
+// CHECK-NEXT: `-Field {{.*}} 'count' 'int'
+
+//==============================================================================
+// __counted_by on struct member pointer in type attribute position
+//==============================================================================
+// TODO: Correctly parse counted_by as a type attribute. Currently it is parsed
+// as a declaration attribute and is **not** late parsed resulting in the `count`
+// field being unavailable.
+//
+// See `clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c` for test
+// cases.
diff --git a/clang/test/AST/attr-counted-by-struct-ptrs.c b/clang/test/AST/attr-counted-by-struct-ptrs.c
new file mode 100644
index 00000000000000..79a453d239cd52
--- /dev/null
+++ b/clang/test/AST/attr-counted-by-struct-ptrs.c
@@ -0,0 +1,117 @@
+// RUN: %clang_cc1 %s -ast-dump | FileCheck %s
+
+#define __counted_by(f) __attribute__((counted_by(f)))
+
+struct size_unknown;
+struct size_known {
+ int field;
+};
+
+//==============================================================================
+// __counted_by on struct member pointer in decl attribute position
+//==============================================================================
+
+// CHECK-LABEL: RecordDecl {{.+}} struct on_member_pointer_complete_ty definition
+// CHECK-NEXT: |-FieldDecl {{.+}} referenced count 'int'
+// CHECK-NEXT: `-FieldDecl {{.+}} buf 'struct size_known * __counted_by(count)':'struct size_known *'
+struct on_member_pointer_complete_ty {
+ int count;
+ struct size_known * buf __counted_by(count);
+};
+
+// CHECK-LABEL: RecordDecl {{.+}} struct on_pointer_anon_buf definition
+// CHECK-NEXT: |-FieldDecl {{.+}} referenced count 'int'
+// CHECK-NEXT: |-RecordDecl {{.+}} struct definition
+// CHECK-NEXT: | `-FieldDecl {{.+}} buf 'struct size_known * __counted_by(count)':'struct size_known *'
+// CHECK-NEXT: |-FieldDecl {{.+}} implicit 'struct on_pointer_anon_buf::(anonymous at [[ANON_STRUCT_PATH:.+]])'
+// CHECK-NEXT: `-IndirectFieldDecl {{.+}} implicit buf 'struct size_known * __counted_by(count)':'struct size_known *'
+// CHECK-NEXT: |-Field {{.+}} '' 'struct on_pointer_anon_buf::(anonymous at [[ANON_STRUCT_PATH]])'
+// CHECK-NEXT: `-Field {{.+}} 'buf' 'struct size_known * __counted_by(count)':'struct size_known *'
+struct on_pointer_anon_buf {
+ int count;
+ struct {
+ struct size_known *buf __counted_by(count);
+ };
+};
+
+struct on_pointer_anon_count {
+ struct {
+ int count;
+ };
+ struct size_known *buf __counted_by(count);
+};
+
+//==============================================================================
+// __counted_by on struct member pointer in type attribute position
+//==============================================================================
+// TODO: Correctly parse counted_by as a type attribute. Currently it is parsed
+// as a declaration attribute
+
+// CHECK-LABEL: RecordDecl {{.+}} struct on_member_pointer_complete_ty_ty_pos definition
+// CHECK-NEXT: |-FieldDecl {{.+}} referenced count 'int'
+// CHECK-NEXT: `-FieldDecl {{.+}} buf 'struct size_known * __counted_by(count)':'struct size_known *'
+struct on_member_pointer_complete_ty_ty_pos {
+ int count;
+ struct size_known *__counted_by(count) buf;
+};
+
+// TODO: This should be forbidden but isn't due to counted_by being treated as a
+// declaration attribute. The attribute ends up on the outer most pointer
+// (allowed by sema) even though syntactically its supposed to be on the inner
+// pointer (would not allowed by sema due to pointee being a function type).
+// CHECK-LABEL: RecordDecl {{.+}} struct on_member_pointer_fn_ptr_ty_ty_pos_inner definition
+// CHECK-NEXT: |-FieldDecl {{.+}} referenced count 'int'
+// CHECK-NEXT: `-FieldDecl {{.+}} fn_ptr 'void (** __counted_by(count))(void)':'void (**)(void)'
+struct on_member_pointer_fn_ptr_ty_ty_pos_inner {
+ int count;
+ void (* __counted_by(count) * fn_ptr)(void);
+};
+
+// FIXME: The generated AST here is wrong. The attribute should be on the inner
+// pointer.
+// CHECK-LABEL: RecordDecl {{.+}} struct on_nested_pointer_inner definition
+// CHECK-NEXT: |-FieldDecl {{.+}} referenced count 'int'
+// CHECK-NEXT: `-FieldDecl {{.+}} buf 'struct size_known ** __counted_by(count)':'struct size_known **'
+struct on_nested_pointer_inner {
+ int count;
+ // TODO: This should be disallowed because in the `-fbounds-safety` model
+ // `__counted_by` can only be nested when used in function parameters.
+ struct size_known *__counted_by(count) *buf;
+};
+
+// CHECK-LABEL: RecordDecl {{.+}} struct on_nested_pointer_outer definition
+// CHECK-NEXT: |-FieldDecl {{.+}} referenced count 'int'
+// CHECK-NEXT: `-FieldDecl {{.+}} buf 'struct size_known ** __counted_by(count)':'struct size_known **'
+struct on_nested_pointer_outer {
+ int count;
+ struct size_known **__counted_by(count) buf;
+};
+
+// CHECK-LABEL: RecordDecl {{.+}} struct on_pointer_anon_buf_ty_pos definition
+// CHECK-NEXT: |-FieldDecl {{.+}} referenced count 'int'
+// CHECK-NEXT: |-RecordDecl {{.+}} struct definition
+// CHECK-NEXT: | `-FieldDecl {{.+}} buf 'struct size_known * __counted_by(count)':'struct size_known *'
+// CHECK-NEXT: |-FieldDecl {{.+}} implicit 'struct on_pointer_anon_buf_ty_pos::(anonymous at [[ANON_STRUCT_PATH2:.+]])'
+// CHECK-NEXT: `-IndirectFieldDecl {{.+}} implicit buf 'struct size_known * __counted_by(count)':'struct size_known *'
+// CHECK-NEXT: |-Field {{.+}} '' 'struct on_pointer_anon_buf_ty_pos::(anonymous at [[ANON_STRUCT_PATH2]])'
+// CHECK-NEXT: `-Field {{.+}} 'buf' 'struct size_known * __counted_by(count)':'struct size_known *'
+struct on_pointer_anon_buf_ty_pos {
+ int count;
+ struct {
+ struct size_known * __counted_by(count) buf;
+ };
+};
+
+// CHECK-LABEL: RecordDecl {{.+}} struct on_pointer_anon_count_ty_pos definition
+// CHECK-NEXT: |-RecordDecl {{.+}} struct definition
+// CHECK-NEXT: | `-FieldDecl {{.+}} count 'int'
+// CHECK-NEXT: |-FieldDecl {{.+}} implicit 'struct on_pointer_anon_count_ty_pos::(anonymous at [[ANON_STRUCT_PATH3:.+]])'
+// CHECK-NEXT: |-IndirectFieldDecl {{.+}} implicit referenced count 'int'
+// CHECK-NEXT: | |-Field {{.+}} '' 'struct on_pointer_anon_count_ty_pos::(anonymous at [[ANON_STRUCT_PATH3]])'
+// CHECK-NEXT: | `-Field {{.+}} 'count' 'int'
+struct on_pointer_anon_count_ty_pos {
+ struct {
+ int count;
+ };
+ struct size_known *__counted_by(count) buf;
+};
diff --git a/clang/test/Sema/attr-counted-by-late-parsed-off.c b/clang/test/Sema/attr-counted-by-late-parsed-off.c
new file mode 100644
index 00000000000000..34f51d10c08389
--- /dev/null
+++ b/clang/test/Sema/attr-counted-by-late-parsed-off.c
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -DNEEDS_LATE_PARSING -fno-experimental-late-parse-attributes -fsyntax-only -verify %s
+// RUN: %clang_cc1 -DNEEDS_LATE_PARSING -fsyntax-only -verify %s
+
+// RUN: %clang_cc1 -UNEEDS_LATE_PARSING -fno-experimental-late-parse-attributes -fsyntax-only -verify=ok %s
+// RUN: %clang_cc1 -UNEEDS_LATE_PARSING -fsyntax-only -verify=ok %s
+
+#define __counted_by(f) __attribute__((counted_by(f)))
+
+struct size_known { int dummy; };
+
+#ifdef NEEDS_LATE_PARSING
+struct on_decl {
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_known *buf __counted_by(count);
+ int count;
+};
+
+#else
+
+// ok-no-diagnostics
+struct on_decl {
+ int count;
+ struct size_known *buf __counted_by(count);
+};
+
+#endif
diff --git a/clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c b/clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c
new file mode 100644
index 00000000000000..f9e78909b9cb62
--- /dev/null
+++ b/clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c
@@ -0,0 +1,192 @@
+// RUN: %clang_cc1 -fexperimental-late-parse-attributes -fsyntax-only -verify %s
+
+#define __counted_by(f) __attribute__((counted_by(f)))
+
+struct size_unknown;
+struct size_known {
+ int field;
+};
+
+//==============================================================================
+// __counted_by on struct member pointer in decl attribute position
+//==============================================================================
+
+struct on_member_pointer_complete_ty {
+ struct size_known * buf __counted_by(count);
+ int count;
+};
+
+struct on_member_pointer_incomplete_ty {
+ struct size_unknown * buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct size_unknown' is an incomplete type}}
+ int count;
+};
+
+struct on_member_pointer_void_ty {
+ void* buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void' is an incomplete type}}
+ int count;
+};
+
+struct on_member_pointer_fn_ty {
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void (void)' is a function type}}
+ void (*fn_ptr)(void) __counted_by(count);
+ int count;
+};
+
+struct has_unannotated_vla {
+ int count;
+ int buffer[];
+};
+
+struct on_member_pointer_struct_with_vla {
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
+ struct has_unannotated_vla* objects __counted_by(count);
+ int count;
+};
+
+struct has_annotated_vla {
+ int count;
+ int buffer[] __counted_by(count);
+};
+
+// Currently prevented because computing the size of `objects` at runtime would
+// require an O(N) walk of `objects` to take into account the length of the VLA
+// in each struct instance.
+struct on_member_pointer_struct_with_annotated_vla {
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
+ struct has_annotated_vla* objects __counted_by(count);
+ int count;
+};
+
+struct on_pointer_anon_buf {
+ // TODO: Support referring to parent scope
+ struct {
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_known *buf __counted_by(count);
+ };
+ int count;
+};
+
+struct on_pointer_anon_count {
+ struct size_known *buf __counted_by(count);
+ struct {
+ int count;
+ };
+};
+
+//==============================================================================
+// __counted_by on struct member pointer in type attribute position
+//==============================================================================
+// TODO: Correctly parse counted_by as a type attribute. Currently it is parsed
+// as a declaration attribute and is **not** late parsed resulting in the `count`
+// field being unavailable.
+
+struct on_member_pointer_complete_ty_ty_pos {
+ // TODO: Allow this
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_known *__counted_by(count) buf;
+ int count;
+};
+
+struct on_member_pointer_incomplete_ty_ty_pos {
+ // TODO: Allow this
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_unknown * __counted_by(count) buf;
+ int count;
+};
+
+struct on_member_pointer_void_ty_ty_pos {
+ // TODO: This should fail because the attribute is
+ // on a pointer with the pointee being an incomplete type.
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ void *__counted_by(count) buf;
+ int count;
+};
+
+struct on_member_pointer_fn_ty_ty_pos {
+ // TODO: This should fail because the attribute is
+ // on a pointer with the pointee being a function type.
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ void (* __counted_by(count) fn_ptr)(void);
+ int count;
+};
+
+struct on_member_pointer_fn_ptr_ty_ty_pos {
+ // TODO: Allow this
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ void (** __counted_by(count) fn_ptr)(void);
+ int count;
+};
+
+struct on_member_pointer_fn_ptr_ty_ty_pos_inner {
+ // TODO: This should fail because the attribute is
+ // on a pointer with the pointee being a function type.
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ void (* __counted_by(count) * fn_ptr)(void);
+ int count;
+};
+
+struct on_member_pointer_struct_with_vla_ty_pos {
+ // TODO: This should fail because the attribute is
+ // on a pointer with the pointee being a struct type with a VLA.
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct has_unannotated_vla *__counted_by(count) objects;
+ int count;
+};
+
+struct on_member_pointer_struct_with_annotated_vla_ty_pos {
+ // TODO: This should fail because the attribute is
+ // on a pointer with the pointee being a struct type with a VLA.
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct has_annotated_vla* __counted_by(count) objects;
+ int count;
+};
+
+struct on_nested_pointer_inner {
+ // TODO: This should be disallowed because in the `-fbounds-safety` model
+ // `__counted_by` can only be nested when used in function parameters.
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_known *__counted_by(count) *buf;
+ int count;
+};
+
+struct on_nested_pointer_outer {
+ // TODO: Allow this
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_known **__counted_by(count) buf;
+ int count;
+};
+
+struct on_pointer_anon_buf_ty_pos {
+ struct {
+ // TODO: Support referring to parent scope
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_known * __counted_by(count) buf;
+ };
+ int count;
+};
+
+struct on_pointer_anon_count_ty_pos {
+ // TODO: Allow this
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ struct size_known *__counted_by(count) buf;
+ struct {
+ int count;
+ };
+};
+
+//==============================================================================
+// __counted_by on struct non-pointer members
+//==============================================================================
+
+struct on_pod_ty {
+ // expected-error at +1{{'counted_by' only applies to pointers or C99 flexible array members}}
+ int wrong_ty __counted_by(count);
+ int count;
+};
+
+struct on_void_ty {
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{field has incomplete type 'void'}}
+ void wrong_ty __counted_by(count);
+ int count;
+};
diff --git a/clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c b/clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c
new file mode 100644
index 00000000000000..fa76f236f90e57
--- /dev/null
+++ b/clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c
@@ -0,0 +1,17 @@
+// __SVInt8_t is specific to ARM64 so specify that in the target triple
+// RUN: %clang_cc1 -triple arm64-apple-darwin -fsyntax-only -verify %s
+
+#define __counted_by(f) __attribute__((counted_by(f)))
+
+struct on_sizeless_pointee_ty {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because '__SVInt8_t' is a sizeless type}}
+ __SVInt8_t* member __counted_by(count);
+};
+
+struct on_sizeless_ty {
+ int count;
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{field has sizeless type '__SVInt8_t'}}
+ __SVInt8_t member __counted_by(count);
+};
diff --git a/clang/test/Sema/attr-counted-by-struct-ptrs.c b/clang/test/Sema/attr-counted-by-struct-ptrs.c
new file mode 100644
index 00000000000000..f3d8dd3c36bd35
--- /dev/null
+++ b/clang/test/Sema/attr-counted-by-struct-ptrs.c
@@ -0,0 +1,170 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+#define __counted_by(f) __attribute__((counted_by(f)))
+
+struct size_unknown;
+struct size_known {
+ int field;
+};
+
+//==============================================================================
+// __counted_by on struct member pointer in decl attribute position
+//==============================================================================
+
+struct on_member_pointer_complete_ty {
+ int count;
+ struct size_known * buf __counted_by(count);
+};
+
+struct on_member_pointer_incomplete_ty {
+ int count;
+ struct size_unknown * buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct size_unknown' is an incomplete type}}
+};
+
+struct on_member_pointer_void_ty {
+ int count;
+ void* buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void' is an incomplete type}}
+};
+
+struct on_member_pointer_fn_ty {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void (void)' is a function type}}
+ void (*fn_ptr)(void) __counted_by(count);
+};
+
+struct has_unannotated_vla {
+ int count;
+ int buffer[];
+};
+
+struct on_member_pointer_struct_with_vla {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
+ struct has_unannotated_vla* objects __counted_by(count);
+};
+
+struct has_annotated_vla {
+ int count;
+ int buffer[] __counted_by(count);
+};
+
+// Currently prevented because computing the size of `objects` at runtime would
+// require an O(N) walk of `objects` to take into account the length of the VLA
+// in each struct instance.
+struct on_member_pointer_struct_with_annotated_vla {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
+ struct has_annotated_vla* objects __counted_by(count);
+};
+
+struct on_pointer_anon_buf {
+ int count;
+ struct {
+ struct size_known *buf __counted_by(count);
+ };
+};
+
+struct on_pointer_anon_count {
+ struct {
+ int count;
+ };
+ struct size_known *buf __counted_by(count);
+};
+
+//==============================================================================
+// __counted_by on struct member pointer in type attribute position
+//==============================================================================
+// TODO: Correctly parse counted_by as a type attribute. Currently it is parsed
+// as a declaration attribute
+
+struct on_member_pointer_complete_ty_ty_pos {
+ int count;
+ struct size_known *__counted_by(count) buf ;
+};
+
+struct on_member_pointer_incomplete_ty_ty_pos {
+ int count;
+ struct size_unknown * __counted_by(count) buf; // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct size_unknown' is an incomplete type}}
+};
+
+struct on_member_pointer_void_ty_ty_pos {
+ int count;
+ void *__counted_by(count) buf; // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void' is an incomplete type}}
+};
+
+struct on_member_pointer_fn_ty_ty_pos {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void (void)' is a function type}}
+ void (* __counted_by(count) fn_ptr)(void);
+};
+
+struct on_member_pointer_fn_ptr_ty_ty_pos {
+ int count;
+ // A buffer of function pointers that is counted by `count` is ok.
+ void (** __counted_by(count) fn_ptr)(void);
+};
+
+// TODO: This should be forbidden but isn't due to counted_by being treated
+// as a declaration attribute.
+struct on_member_pointer_fn_ptr_ty_ty_pos_inner {
+ int count;
+ void (* __counted_by(count) * fn_ptr)(void);
+};
+
+struct on_member_pointer_struct_with_vla_ty_pos {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
+ struct has_unannotated_vla *__counted_by(count) objects;
+};
+
+// Currently prevented because computing the size of `objects` at runtime would
+// require an O(N) walk of `objects` to take into account the length of the VLA
+// in each struct instance.
+struct on_member_pointer_struct_with_annotated_vla_ty_pos {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
+ struct has_annotated_vla* __counted_by(count) objects;
+};
+
+struct on_nested_pointer_inner {
+ // TODO: This should be disallowed because in the `-fbounds-safety` model
+ // `__counted_by` can only be nested when used in function parameters.
+ int count;
+ struct size_known *__counted_by(count) *buf;
+};
+
+struct on_nested_pointer_outer {
+ int count;
+ struct size_known **__counted_by(count) buf;
+};
+
+struct on_pointer_anon_buf_ty_pos {
+ int count;
+ struct {
+ struct size_known * __counted_by(count) buf;
+ };
+};
+
+struct on_pointer_anon_count_ty_pos {
+ struct {
+ int count;
+ };
+ struct size_known *__counted_by(count) buf;
+};
+
+//==============================================================================
+// __counted_by on struct non-pointer members
+//==============================================================================
+
+struct on_pod_ty {
+ int count;
+ // expected-error at +1{{'counted_by' only applies to pointers or C99 flexible array members}}
+ int wrong_ty __counted_by(count);
+};
+
+struct on_void_ty {
+ int count;
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{field has incomplete type 'void'}}
+ void wrong_ty __counted_by(count);
+};
diff --git a/clang/test/Sema/attr-counted-by.c b/clang/test/Sema/attr-counted-by.c
index d5d4ebf5573922..54faf9b888087c 100644
--- a/clang/test/Sema/attr-counted-by.c
+++ b/clang/test/Sema/attr-counted-by.c
@@ -95,12 +95,13 @@ struct array_of_ints_count {
struct not_a_fam {
int count;
- struct bar *non_fam __counted_by(count); // expected-error {{'counted_by' only applies to C99 flexible array members}}
+ // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct bar' is an incomplete type}}
+ struct bar *non_fam __counted_by(count);
};
struct not_a_c99_fam {
int count;
- struct bar *non_c99_fam[0] __counted_by(count); // expected-error {{'counted_by' only applies to C99 flexible array members}}
+ struct bar *non_c99_fam[0] __counted_by(count); // expected-error {{'counted_by' on arrays only applies to C99 flexible array members}}
};
struct annotated_with_anon_struct {
>From 9ec320321115d883bcb2b9fb6be7f5f95083d5e6 Mon Sep 17 00:00:00 2001
From: Dan Liew <dan at su-root.co.uk>
Date: Fri, 3 May 2024 12:21:11 -0700
Subject: [PATCH 2/3] * Tweak new diagnostic message * Rename
`attr-counted-by.c` -> `attr-counted-by-vla.c` * Disallow `__counted_by` on
VLA if element type is a struct with a VLA (addresses @hnrklssn 's
feedback)
---
.../clang/Basic/DiagnosticSemaKinds.td | 8 +-
clang/lib/Sema/SemaDeclAttr.cpp | 49 +++++++-----
.../attr-counted-by-late-parsed-struct-ptrs.c | 24 ++++--
...tr-counted-by-struct-ptrs-sizeless-types.c | 2 +-
clang/test/Sema/attr-counted-by-struct-ptrs.c | 38 +++++++---
.../Sema/attr-counted-by-vla-sizeless-types.c | 11 +++
...ttr-counted-by.c => attr-counted-by-vla.c} | 76 ++++++++++++++++++-
7 files changed, 168 insertions(+), 40 deletions(-)
create mode 100644 clang/test/Sema/attr-counted-by-vla-sizeless-types.c
rename clang/test/Sema/{attr-counted-by.c => attr-counted-by-vla.c} (50%)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 0ab2a96c7b464b..6f566e12598287 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6537,14 +6537,16 @@ def err_counted_by_attr_refer_to_union : Error<
def note_flexible_array_counted_by_attr_field : Note<
"field %0 declared here">;
def err_counted_by_attr_pointee_unknown_size : Error<
- "'counted_by' cannot be applied a pointer with pointee with unknown size "
- "because %0 is %select{"
+ "'counted_by' cannot be applied to %select{"
+ "a pointer with pointee|" // pointer
+ "an array with element}0" // array
+ " of unknown size because %1 is %select{"
"an incomplete type|" // CountedByInvalidPointeeTypeKind::INCOMPLETE
"a sizeless type|" // CountedByInvalidPointeeTypeKind::SIZELESS
"a function type|" // CountedByInvalidPointeeTypeKind::FUNCTION
// CountedByInvalidPointeeTypeKind::FLEXIBLE_ARRAY_MEMBER
"a struct type with a flexible array member"
- "}1">;
+ "}2">;
let CategoryName = "ARC Semantic Issue" in {
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 7ae1e09c7a5dcd..1e39f8f8f6f3c9 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -8626,26 +8626,37 @@ static bool CheckCountedByAttrOnField(
return true;
}
+ CountedByInvalidPointeeTypeKind InvalidTypeKind =
+ CountedByInvalidPointeeTypeKind::VALID;
+ QualType PointeeTy;
+ int SelectPtrOrArr = 0;
if (FieldTy->isPointerType()) {
- CountedByInvalidPointeeTypeKind InvalidTypeKind =
- CountedByInvalidPointeeTypeKind::VALID;
- const auto PointeeTy = FieldTy->getPointeeType();
- if (PointeeTy->isIncompleteType()) {
- InvalidTypeKind = CountedByInvalidPointeeTypeKind::INCOMPLETE;
- } else if (PointeeTy->isSizelessType()) {
- InvalidTypeKind = CountedByInvalidPointeeTypeKind::SIZELESS;
- } else if (PointeeTy->isFunctionType()) {
- InvalidTypeKind = CountedByInvalidPointeeTypeKind::FUNCTION;
- } else if (PointeeTy->isStructureTypeWithFlexibleArrayMember()) {
- InvalidTypeKind = CountedByInvalidPointeeTypeKind::FLEXIBLE_ARRAY_MEMBER;
- }
-
- if (InvalidTypeKind != CountedByInvalidPointeeTypeKind::VALID) {
- S.Diag(FD->getBeginLoc(), diag::err_counted_by_attr_pointee_unknown_size)
- << FieldTy->getPointeeType() << (int)InvalidTypeKind
- << FD->getSourceRange();
- return true;
- }
+ PointeeTy = FieldTy->getPointeeType();
+ SelectPtrOrArr = 0;
+ } else {
+ assert(FieldTy->isArrayType());
+ const ArrayType *AT = S.getASTContext().getAsArrayType(FieldTy);
+ PointeeTy = AT->getElementType();
+ SelectPtrOrArr = 1;
+ }
+ // Note: The `Decl::isFlexibleArrayMemberLike` check earlier on means
+ // only `PointeeTy->isStructureTypeWithFlexibleArrayMember()` is reachable
+ // when `FieldTy->isArrayType()`.
+ if (PointeeTy->isIncompleteType()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::INCOMPLETE;
+ } else if (PointeeTy->isSizelessType()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::SIZELESS;
+ } else if (PointeeTy->isFunctionType()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::FUNCTION;
+ } else if (PointeeTy->isStructureTypeWithFlexibleArrayMember()) {
+ InvalidTypeKind = CountedByInvalidPointeeTypeKind::FLEXIBLE_ARRAY_MEMBER;
+ }
+
+ if (InvalidTypeKind != CountedByInvalidPointeeTypeKind::VALID) {
+ S.Diag(FD->getBeginLoc(), diag::err_counted_by_attr_pointee_unknown_size)
+ << SelectPtrOrArr << PointeeTy << (int)InvalidTypeKind
+ << FD->getSourceRange();
+ return true;
}
// Check the expression
diff --git a/clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c b/clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c
index f9e78909b9cb62..d24b79c61b63be 100644
--- a/clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c
+++ b/clang/test/Sema/attr-counted-by-late-parsed-struct-ptrs.c
@@ -17,17 +17,24 @@ struct on_member_pointer_complete_ty {
};
struct on_member_pointer_incomplete_ty {
- struct size_unknown * buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct size_unknown' is an incomplete type}}
+ struct size_unknown * buf __counted_by(count); // expected-error{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct size_unknown' is an incomplete type}}
int count;
};
+struct on_member_pointer_const_incomplete_ty {
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'const struct size_unknown' is an incomplete type}}
+ const struct size_unknown * buf __counted_by(count);
+ int count;
+};
+
+
struct on_member_pointer_void_ty {
- void* buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void' is an incomplete type}}
+ void* buf __counted_by(count); // expected-error{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'void' is an incomplete type}}
int count;
};
struct on_member_pointer_fn_ty {
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void (void)' is a function type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'void (void)' is a function type}}
void (*fn_ptr)(void) __counted_by(count);
int count;
};
@@ -38,7 +45,7 @@ struct has_unannotated_vla {
};
struct on_member_pointer_struct_with_vla {
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
struct has_unannotated_vla* objects __counted_by(count);
int count;
};
@@ -52,7 +59,7 @@ struct has_annotated_vla {
// require an O(N) walk of `objects` to take into account the length of the VLA
// in each struct instance.
struct on_member_pointer_struct_with_annotated_vla {
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
struct has_annotated_vla* objects __counted_by(count);
int count;
};
@@ -94,6 +101,13 @@ struct on_member_pointer_incomplete_ty_ty_pos {
int count;
};
+struct on_member_pointer_const_incomplete_ty_ty_pos {
+ // TODO: Allow this
+ // expected-error at +1{{use of undeclared identifier 'count'}}
+ const struct size_unknown * __counted_by(count) buf;
+ int count;
+};
+
struct on_member_pointer_void_ty_ty_pos {
// TODO: This should fail because the attribute is
// on a pointer with the pointee being an incomplete type.
diff --git a/clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c b/clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c
index fa76f236f90e57..9b0f2eafb13c2b 100644
--- a/clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c
+++ b/clang/test/Sema/attr-counted-by-struct-ptrs-sizeless-types.c
@@ -5,7 +5,7 @@
struct on_sizeless_pointee_ty {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because '__SVInt8_t' is a sizeless type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because '__SVInt8_t' is a sizeless type}}
__SVInt8_t* member __counted_by(count);
};
diff --git a/clang/test/Sema/attr-counted-by-struct-ptrs.c b/clang/test/Sema/attr-counted-by-struct-ptrs.c
index f3d8dd3c36bd35..c5128e0b99ad5f 100644
--- a/clang/test/Sema/attr-counted-by-struct-ptrs.c
+++ b/clang/test/Sema/attr-counted-by-struct-ptrs.c
@@ -18,17 +18,25 @@ struct on_member_pointer_complete_ty {
struct on_member_pointer_incomplete_ty {
int count;
- struct size_unknown * buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct size_unknown' is an incomplete type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct size_unknown' is an incomplete type}}
+ struct size_unknown * buf __counted_by(count);
+};
+
+struct on_member_pointer_const_incomplete_ty {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'const struct size_unknown' is an incomplete type}}
+ const struct size_unknown * buf __counted_by(count);
};
struct on_member_pointer_void_ty {
int count;
- void* buf __counted_by(count); // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void' is an incomplete type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'void' is an incomplete type}}
+ void* buf __counted_by(count);
};
struct on_member_pointer_fn_ty {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void (void)' is a function type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'void (void)' is a function type}}
void (*fn_ptr)(void) __counted_by(count);
};
@@ -39,7 +47,7 @@ struct has_unannotated_vla {
struct on_member_pointer_struct_with_vla {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
struct has_unannotated_vla* objects __counted_by(count);
};
@@ -53,7 +61,7 @@ struct has_annotated_vla {
// in each struct instance.
struct on_member_pointer_struct_with_annotated_vla {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
struct has_annotated_vla* objects __counted_by(count);
};
@@ -79,22 +87,30 @@ struct on_pointer_anon_count {
struct on_member_pointer_complete_ty_ty_pos {
int count;
- struct size_known *__counted_by(count) buf ;
+ struct size_known *__counted_by(count) buf;
};
struct on_member_pointer_incomplete_ty_ty_pos {
int count;
- struct size_unknown * __counted_by(count) buf; // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct size_unknown' is an incomplete type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct size_unknown' is an incomplete type}}
+ struct size_unknown * __counted_by(count) buf;
+};
+
+struct on_member_pointer_const_incomplete_ty_ty_pos {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'const struct size_unknown' is an incomplete type}}
+ const struct size_unknown * __counted_by(count) buf;
};
struct on_member_pointer_void_ty_ty_pos {
int count;
- void *__counted_by(count) buf; // expected-error{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void' is an incomplete type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'void' is an incomplete type}}
+ void *__counted_by(count) buf;
};
struct on_member_pointer_fn_ty_ty_pos {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'void (void)' is a function type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'void (void)' is a function type}}
void (* __counted_by(count) fn_ptr)(void);
};
@@ -113,7 +129,7 @@ struct on_member_pointer_fn_ptr_ty_ty_pos_inner {
struct on_member_pointer_struct_with_vla_ty_pos {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct has_unannotated_vla' is a struct type with a flexible array member}}
struct has_unannotated_vla *__counted_by(count) objects;
};
@@ -122,7 +138,7 @@ struct on_member_pointer_struct_with_vla_ty_pos {
// in each struct instance.
struct on_member_pointer_struct_with_annotated_vla_ty_pos {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
+ // expected-error at +1{{counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct has_annotated_vla' is a struct type with a flexible array member}}
struct has_annotated_vla* __counted_by(count) objects;
};
diff --git a/clang/test/Sema/attr-counted-by-vla-sizeless-types.c b/clang/test/Sema/attr-counted-by-vla-sizeless-types.c
new file mode 100644
index 00000000000000..31c0007501c48d
--- /dev/null
+++ b/clang/test/Sema/attr-counted-by-vla-sizeless-types.c
@@ -0,0 +1,11 @@
+// __SVInt8_t is specific to ARM64 so specify that in the target triple
+// RUN: %clang_cc1 -triple arm64-apple-darwin -fsyntax-only -verify %s
+
+#define __counted_by(f) __attribute__((counted_by(f)))
+
+struct on_sizeless_elt_ty {
+ int count;
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{array has sizeless element type '__SVInt8_t'}}
+ __SVInt8_t arr[] __counted_by(count);
+};
diff --git a/clang/test/Sema/attr-counted-by.c b/clang/test/Sema/attr-counted-by-vla.c
similarity index 50%
rename from clang/test/Sema/attr-counted-by.c
rename to clang/test/Sema/attr-counted-by-vla.c
index 54faf9b888087c..745d83d1179ad2 100644
--- a/clang/test/Sema/attr-counted-by.c
+++ b/clang/test/Sema/attr-counted-by-vla.c
@@ -95,7 +95,7 @@ struct array_of_ints_count {
struct not_a_fam {
int count;
- // expected-error at +1{{'counted_by' cannot be applied a pointer with pointee with unknown size because 'struct bar' is an incomplete type}}
+ // expected-error at +1{{'counted_by' cannot be applied to a pointer with pointee of unknown size because 'struct bar' is an incomplete type}}
struct bar *non_fam __counted_by(count);
};
@@ -111,3 +111,77 @@ struct annotated_with_anon_struct {
int array[] __counted_by(crount); // expected-error {{use of undeclared identifier 'crount'}}
};
};
+
+//==============================================================================
+// __counted_by on a struct VLA with element type that has unknown size
+//==============================================================================
+
+struct size_unknown; // expected-note 2{{forward declaration of 'struct size_unknown'}}
+struct on_member_arr_incomplete_ty_ty_pos {
+ int count;
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{array has incomplete element type 'struct size_unknown'}}
+ struct size_unknown buf[] __counted_by(count);
+};
+
+struct on_member_arr_incomplete_const_ty_ty_pos {
+ int count;
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{array has incomplete element type 'const struct size_unknown'}}
+ const struct size_unknown buf[] __counted_by(count);
+};
+
+struct on_member_arr_void_ty_ty_pos {
+ int count;
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{array has incomplete element type 'void'}}
+ void buf[] __counted_by(count);
+};
+
+typedef void(fn_ty)(int);
+
+struct on_member_arr_fn_ty {
+ int count;
+ // expected-error at +2{{'counted_by' only applies to pointers or C99 flexible array members}}
+ // expected-error at +1{{'buf' declared as array of functions of type 'fn_ty' (aka 'void (int)')}}
+ fn_ty buf[] __counted_by(count);
+};
+
+
+
+// `buffer_of_structs_with_unnannotated_vla`,
+// `buffer_of_structs_with_annotated_vla`, and
+// `buffer_of_const_structs_with_annotated_vla` are currently prevented because
+// computing the size of `Arr` at runtime would require an O(N) walk of `Arr`
+// elements to take into account the length of the VLA in each struct instance.
+
+struct has_unannotated_VLA {
+ int count;
+ char buffer[];
+};
+
+struct has_annotated_VLA {
+ int count;
+ char buffer[] __counted_by(count);
+};
+
+struct buffer_of_structs_with_unnannotated_vla {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied to an array with element of unknown size because 'struct has_unannotated_VLA' is a struct type with a flexible array member}}
+ struct has_unannotated_VLA Arr[] __counted_by(count);
+};
+
+
+struct buffer_of_structs_with_annotated_vla {
+ int count;
+ // expected-error at +1{{'counted_by' cannot be applied to an array with element of unknown size because 'struct has_annotated_VLA' is a struct type with a flexible array member}}
+ struct has_annotated_VLA Arr[] __counted_by(count);
+};
+
+struct buffer_of_const_structs_with_annotated_vla {
+ int count;
+ // Make sure the `const` qualifier is printed when printing the element type.
+ // expected-error at +1{{'counted_by' cannot be applied to an array with element of unknown size because 'const struct has_annotated_VLA' is a struct type with a flexible array member}}
+ const struct has_annotated_VLA Arr[] __counted_by(count);
+};
+
>From adfd09809640860ad7670482b908a6be71a1c8ef Mon Sep 17 00:00:00 2001
From: Dan Liew <dan at su-root.co.uk>
Date: Fri, 3 May 2024 13:26:20 -0700
Subject: [PATCH 3/3] Address @bwendling 's initial feedback
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/lib/AST/Type.cpp | 4 +---
clang/lib/Parse/ParseDecl.cpp | 2 +-
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 81d0a89b294878..09119394cfad68 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -336,6 +336,9 @@ Attribute Changes in Clang
- Clang now warns that the ``exclude_from_explicit_instantiation`` attribute
is ignored when applied to a local class or a member thereof.
+- The ``counted_by`` attribute is now allowed on pointers that are members of a
+ struct in C.
+
- The ``counted_by`` attribute can now be late parsed in C when
``-fexperimental-late-parse-attributes`` is passed but only when attribute is
used in the declaration attribute position. This allows using the
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index 316d70e0b79ecf..17ed7d3dc4236b 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -638,9 +638,7 @@ bool Type::isStructureTypeWithFlexibleArrayMember() const {
const auto *Decl = RT->getDecl();
if (!Decl->isStruct())
return false;
- if (!Decl->hasFlexibleArrayMember())
- return false;
- return true;
+ return Decl->hasFlexibleArrayMember();
}
bool Type::isObjCBoxableRecordType() const {
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 470d26fb3d73be..8999f4cc344dc4 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3284,7 +3284,7 @@ void Parser::ParseAlignmentSpecifier(ParsedAttributes &Attrs,
void Parser::DistributeCLateParsedAttrs(Decl *Dcl,
LateParsedAttrList *LateAttrs) {
- assert(Dcl);
+ assert(Dcl && "Dcl cannot be null");
if (!LateAttrs)
return;
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