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ast-print generates empty parameter for attributes with optional string parameter #62996

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strimo378 opened this issue May 30, 2023 · 7 comments
Open

ast-print generates empty parameter for attributes with optional string parameter #62996

strimo378 opened this issue May 30, 2023 · 7 comments
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clang:frontend Language frontend issues, e.g. anything involving "Sema"

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@strimo378
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strimo378 commented May 30, 2023 •
edited by VoltrexKeyva

Hi all,

the AST printer (-Xclang -ast-print) always generates an empty parameter for attributes with optional string parameters.

The following code (see https://godbolt.org/z/v69YW7rsb)

int a() __attribute__((warn_unused_result));

int b1() __attribute__((deprecated));
int b2() __attribute__((deprecated("xyz")));
int b3() __attribute__((deprecated("xyz", "y")));

is generates as

int a() __attribute__((warn_unused_result("")));
int b1() __attribute__((deprecated("")));
int b2() __attribute__((deprecated("xyz")));
int b3() __attribute__((deprecated("xyz", "y")));

For the attributes of the function a and b1 an empty parameter ("") is added to the output code. In principle, the code is correct for Clang. It is only problematic that for warn_unused_result the optional parameter is not supported by GCC and the code becomes incompatible.

The Clang source code to output an attributes is within the *Attr::printPretty functions within the TableGen'erated file Attrs.inc.
@EugeneZelenko EugeneZelenko added clang:frontend Language frontend issues, e.g. anything involving "Sema" and removed new issue labels May 30, 2023
@llvmbot
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llvmbot commented May 30, 2023

@llvm/issue-subscribers-clang-frontend

@yangdiangzb
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any plan to fix this?

@strimo378
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Not from my side as I am lacking experience how Attrs.inc is generated...

@yangdiangzb
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Not from my side as I am lacking experience how Attrs.inc is generated...

me neither. and since nodiscard and warn_unused_result are sharing the same rule. i have no idea how to fix this without effecting nodiscard

image

image

razmser pushed a commit to razmser/llvm-project that referenced this issue Sep 8, 2023
@strimo378 @razmser
[clang][DeclPrinter] Fix missing semicolon in AST print for methods t…
a33c49e 
…hat are definitions without having a body

DeclPrinter used FunctionDecl::isThisDeclarationADefinition to decide if the decl requires a semicolon at the end. However, there are several methods without body (that require a semicolon) that are definitions.

Fixes llvm#62996

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D156533
@yangdiangzb
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seems your commit doesnt fix this issue problem? @strimo378

@strimo378
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strimo378 commented Sep 21, 2023 •
edited

@yangdiangzb Hmm, yes that is correct. it seems I used the wrong link for the commit. Thanks for the information.

@strimo378 strimo378 reopened this Sep 21, 2023
@shafik shafik mentioned this issue Nov 28, 2023
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@ken-matsui
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Sorry about this. My private fork accidentally closed this issue.

@ken-matsui ken-matsui reopened this May 31, 2024
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@EugeneZelenko @yangdiangzb @ken-matsui @strimo378 @llvmbot