zahiraam added inline comments.
================ Comment at: clang/lib/Frontend/FrontendAction.cpp:845-855 + if (Input.isFile() && Input.getFile() == "-") { + Preprocessor &PP = CI.getPreprocessor(); + std::string PredefineBuffer; + PredefineBuffer.reserve(4080); + llvm::raw_string_ostream Predefines(PredefineBuffer); + Predefines << PP.getPredefines(); + MacroBuilder Builder(Predefines); ---------------- aaron.ballman wrote: > zahiraam wrote: > > aaron.ballman wrote: > > > I'm confused as to why we want to predefine this macro *only* when the > > > input source is stdin? So I'm not certain I understand why this change is > > > desired. > > > > > > e.g., https://godbolt.org/z/E8Y67381r (note how there's no > > > `__FLT_EVAL_METHOD__` defined there) > > I was offering a solution to the issue raised by @glandium in > > https://reviews.llvm.org/D109239. I thought that the issue was only when > > the source is stdin, but obviously not. The default setting should happen > > under no condition. > There have been a lot of reviews over this stuff, so I may be remembering > incorrectly... but I thought it was a conscious decision to *not* predefine > `__FLT_EVAL_METHOD__` because that value changes depending on pragmas in the > TU. I thought the way that macro worked was that we registered it as a macro > and we figure out its value at expansion time. > > (The original report confused me into thinking that `__FLT_EVAL_METHOD__` was > behaving as though it was never defined, so expansion would never result in a > correct value except when the eval method is `0`.) Yes, you are remembering correctly. I looked at older comments and it's something that was intended. We didn't want to pre-define it, until it is set at expansion. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D124004/new/ https://reviews.llvm.org/D124004 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits