Author: Aaron Ballman Date: 2025-05-28T10:07:14-04:00 New Revision: 5e28af04f32455f93975e227d08f502faa45247c
URL: https://github.com/llvm/llvm-project/commit/5e28af04f32455f93975e227d08f502faa45247c DIFF: https://github.com/llvm/llvm-project/commit/5e28af04f32455f93975e227d08f502faa45247c.diff LOG: [C] Fix parsing of [[clang::assume]] (#141747) The assumption attribute is exposed with a Clang spelling, which means we support __attribute__((assume)) as well as [[clang::assume]] as spellings for the attribute. In C++, the [[clang::assume]] spelling worked as expected. In C, that spelling would emit an "unknown attribute ignored" diagnostic. This was happening because we were failing to pass in the scope name and source location when creating the attribute. In C++, this worked by chance because [[assume]] is a known attribute in C++. But in C, where there is thankfully no [[assume]] standard attribute, the lack of a scope meant we would set the attribute kind to "unknown". Added: clang/test/Sema/assume.c Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Parse/Parser.h clang/lib/Parse/ParseDecl.cpp clang/lib/Parse/ParseDeclCXX.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index df8e035a65109..b21b683fb1360 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -226,6 +226,9 @@ C Language Changes - Added the existing ``-Wduplicate-decl-specifier`` diagnostic, which is on by default, to ``-Wc++-compat`` because duplicated declaration specifiers are not valid in C++. +- The ``[[clang::assume()]]`` attribute is now correctly recognized in C. The + ``__attribute__((assume()))`` form has always been supported, so the fix is + specific to the attribute syntax used. C2y Feature Support ^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h index e6492b81dfff8..c4bef4729fd36 100644 --- a/clang/include/clang/Parse/Parser.h +++ b/clang/include/clang/Parse/Parser.h @@ -3037,11 +3037,11 @@ class Parser : public CodeCompletionHandler { /// Parse the argument to C++23's [[assume()]] attribute. Returns true on /// error. - bool ParseCXXAssumeAttributeArg(ParsedAttributes &Attrs, - IdentifierInfo *AttrName, - SourceLocation AttrNameLoc, - SourceLocation *EndLoc, - ParsedAttr::Form Form); + bool + ParseCXXAssumeAttributeArg(ParsedAttributes &Attrs, IdentifierInfo *AttrName, + SourceLocation AttrNameLoc, + IdentifierInfo *ScopeName, SourceLocation ScopeLoc, + SourceLocation *EndLoc, ParsedAttr::Form Form); /// Try to parse an 'identifier' which appears within an attribute-token. /// diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp index f7eb56426f6de..d6c36616bab47 100644 --- a/clang/lib/Parse/ParseDecl.cpp +++ b/clang/lib/Parse/ParseDecl.cpp @@ -676,7 +676,8 @@ void Parser::ParseGNUAttributeArgs( Form); return; } else if (AttrKind == ParsedAttr::AT_CXXAssume) { - ParseCXXAssumeAttributeArg(Attrs, AttrName, AttrNameLoc, EndLoc, Form); + ParseCXXAssumeAttributeArg(Attrs, AttrName, AttrNameLoc, ScopeName, + ScopeLoc, EndLoc, Form); return; } @@ -734,7 +735,8 @@ unsigned Parser::ParseClangAttributeArgs( break; case ParsedAttr::AT_CXXAssume: - ParseCXXAssumeAttributeArg(Attrs, AttrName, AttrNameLoc, EndLoc, Form); + ParseCXXAssumeAttributeArg(Attrs, AttrName, AttrNameLoc, ScopeName, + ScopeLoc, EndLoc, Form); break; } return !Attrs.empty() ? Attrs.begin()->getNumArgs() : 0; diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp index a665487a2f87d..2cf33a856c4f4 100644 --- a/clang/lib/Parse/ParseDeclCXX.cpp +++ b/clang/lib/Parse/ParseDeclCXX.cpp @@ -4452,11 +4452,10 @@ static bool IsBuiltInOrStandardCXX11Attribute(IdentifierInfo *AttrName, } } -bool Parser::ParseCXXAssumeAttributeArg(ParsedAttributes &Attrs, - IdentifierInfo *AttrName, - SourceLocation AttrNameLoc, - SourceLocation *EndLoc, - ParsedAttr::Form Form) { +bool Parser::ParseCXXAssumeAttributeArg( + ParsedAttributes &Attrs, IdentifierInfo *AttrName, + SourceLocation AttrNameLoc, IdentifierInfo *ScopeName, + SourceLocation ScopeLoc, SourceLocation *EndLoc, ParsedAttr::Form Form) { assert(Tok.is(tok::l_paren) && "Not a C++11 attribute argument list"); BalancedDelimiterTracker T(*this, tok::l_paren); T.consumeOpen(); @@ -4498,8 +4497,8 @@ bool Parser::ParseCXXAssumeAttributeArg(ParsedAttributes &Attrs, ArgsUnion Assumption = Res.get(); auto RParen = Tok.getLocation(); T.consumeClose(); - Attrs.addNew(AttrName, SourceRange(AttrNameLoc, RParen), nullptr, - SourceLocation(), &Assumption, 1, Form); + Attrs.addNew(AttrName, SourceRange(AttrNameLoc, RParen), ScopeName, ScopeLoc, + &Assumption, 1, Form); if (EndLoc) *EndLoc = RParen; @@ -4565,7 +4564,8 @@ bool Parser::ParseCXX11AttributeArgs( ScopeName, ScopeLoc, Form); // So does C++23's assume() attribute. else if (!ScopeName && AttrName->isStr("assume")) { - if (ParseCXXAssumeAttributeArg(Attrs, AttrName, AttrNameLoc, EndLoc, Form)) + if (ParseCXXAssumeAttributeArg(Attrs, AttrName, AttrNameLoc, nullptr, + SourceLocation{}, EndLoc, Form)) return true; NumArgs = 1; } else diff --git a/clang/test/Sema/assume.c b/clang/test/Sema/assume.c new file mode 100644 index 0000000000000..07a5490addfaf --- /dev/null +++ b/clang/test/Sema/assume.c @@ -0,0 +1,25 @@ +// RUN: %clang_cc1 -std=c23 %s -verify + +// Validate that the attribute works in C. +static_assert(!__has_c_attribute(assume)); +static_assert(__has_c_attribute(clang::assume)); +static_assert(__has_attribute(assume)); + +void test(int n) { + // Smoke test. + __attribute__((assume(true))); + [[clang::assume(true)]]; + + // Test diagnostics + __attribute__((assume)); // expected-error {{'assume' attribute takes one argument}} + __attribute__((assume())); // expected-error {{expected expression}} + [[clang::assume]]; // expected-error {{'assume' attribute takes one argument}} + [[clang::assume()]]; // expected-error {{expected expression}} + + __attribute__((assume(n++))); // expected-warning {{assumption is ignored because it contains (potential) side-effects}} + [[clang::assume(n++)]]; // expected-warning {{assumption is ignored because it contains (potential) side-effects}} + + [[clang::assume(true)]] int x; // expected-error {{'assume' attribute cannot be applied to a declaration}} + __attribute__((assume(true))) int y; // expected-error {{'assume' attribute cannot be applied to a declaration}} +} + _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
