[Clang] prevent crash in early parsing of enable_if for C function declarators with identifier-list parameters (#174017) Fixes #173826 --- This patch resolves an issue where Clang could crash while parsing the `enable_if` attribute on C function declarators with identifier-list parameters. In C, identifier-list function declarators use parameter identifiers rather than full parameter declarations, as specified by the C spec. Since `enable_if` is parsed early to participate in redeclaration checks https://github.com/llvm/llvm-project/blob/0f3a9f658a7f459b9aa701ec42a999b645653862/clang/lib/Parse/ParseDecl.cpp#L674-L675 the parser could encounter such identifiers before their parameter declarations exist and incorrectly assume they were already formed, leading to an assertion failure. This change makes the early `enable_if` parsing path handle parameters that have not yet been declared, preventing the crash while preserving existing behavior for well-formed function prototypes.
Welcome to the LLVM project!
This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.
The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.
Other components include: the libc++ C++ standard library, the LLD linker, and more.
Consult the Getting Started with LLVM page for information on building and running LLVM.
For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.
Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.
The LLVM project has adopted a code of conduct for participants to all modes of communication within the project.