A "Safe C++" Being Explored Using The New ClangIR
([LLVM] 3 Hours Ago
Safe C++ With ClangIR)
- Reference: 0001515254
- News link: https://www.phoronix.com/news/RFC-Safe-CXX-Using-ClangIR
- Source link:
An interesting "request for comments" proposal I have been meaning to write about since last month is in-development work developing "Safe C++" as an extension to the LLVM Clang compiler and making use of the new, in-development ClangIR.
This isn't the first time there has been a proposal for a "safe" C++ while at the end of November Chuanqi Xu announced this newest initiative to come up with a "Safe C++" based on the ClangIR intermediate representation that would come down to being a pure subset of ISO C++ with a few ignorable pragma and attributes. The simpler approach would allow compiling the subset by other C++ compilers not supporting this "safe" dialect.
ClangIR is the new intermediate representation (IR) that has been brewing as an MLIR dialect for C/C++ languages that is described in the documentation as being between Clang's AST and LLVM IR. ClangIR can handle C/C++ higher level semantics for better diagnostics and performance optimizations that are harder to achieve in pure Clang AST or LLVM IR. Those wanting to learn more about the in-development ClangIR can do so via the [1]documentation for that in-progress effort.
Chuanqi Xu is looking to leverage ClangIR to produce a safer C++ and has already produced a demo implementation. Among the proposal is adding a pragma "#pragma clang SafeCXX" for defining the same C++ code that other compilers can ignore if unsupported. Similarly there would be a "#pragma clang UnsafeCXX" too for sections of unsafe C++ code.
The thinking is with the ClangIR-based Safe C++ to provide borrow checking, different handling for deprecated calls, deprecating the user of pointers / taking addresses / dereferencing, references within async functions, and other changes to make C++ code safer by better leveraging modern compiler technologies within LLVM/Clang.
The proposal is a bit premature with ClangIR itself not yet being stabilized but those interested can see the RFC proposal on the [2]LLVM Discourse . Some of the early prototyped code can be found via [3]this GitHub repository . It will be interesting to see what comes of this safe C++ effort and more broadly the ClangIR development in 2025.
[1] https://llvm.github.io/clangir/
[2] https://discourse.llvm.org/t/rfc-a-clangir-based-safe-c/83245
[3] https://github.com/ChuanqiXu9/clangir
This isn't the first time there has been a proposal for a "safe" C++ while at the end of November Chuanqi Xu announced this newest initiative to come up with a "Safe C++" based on the ClangIR intermediate representation that would come down to being a pure subset of ISO C++ with a few ignorable pragma and attributes. The simpler approach would allow compiling the subset by other C++ compilers not supporting this "safe" dialect.
ClangIR is the new intermediate representation (IR) that has been brewing as an MLIR dialect for C/C++ languages that is described in the documentation as being between Clang's AST and LLVM IR. ClangIR can handle C/C++ higher level semantics for better diagnostics and performance optimizations that are harder to achieve in pure Clang AST or LLVM IR. Those wanting to learn more about the in-development ClangIR can do so via the [1]documentation for that in-progress effort.
Chuanqi Xu is looking to leverage ClangIR to produce a safer C++ and has already produced a demo implementation. Among the proposal is adding a pragma "#pragma clang SafeCXX" for defining the same C++ code that other compilers can ignore if unsupported. Similarly there would be a "#pragma clang UnsafeCXX" too for sections of unsafe C++ code.
The thinking is with the ClangIR-based Safe C++ to provide borrow checking, different handling for deprecated calls, deprecating the user of pointers / taking addresses / dereferencing, references within async functions, and other changes to make C++ code safer by better leveraging modern compiler technologies within LLVM/Clang.
The proposal is a bit premature with ClangIR itself not yet being stabilized but those interested can see the RFC proposal on the [2]LLVM Discourse . Some of the early prototyped code can be found via [3]this GitHub repository . It will be interesting to see what comes of this safe C++ effort and more broadly the ClangIR development in 2025.
[1] https://llvm.github.io/clangir/
[2] https://discourse.llvm.org/t/rfc-a-clangir-based-safe-c/83245
[3] https://github.com/ChuanqiXu9/clangir
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