================ @@ -1073,6 +1073,28 @@ inputs. Here is some example of ``$``-prefixed options: Language and Target-Independent Features ======================================== +Freestanding Builds +------------------- +Passing the ``-ffreestanding`` flag causes Clang to build for a freestanding +(rather than a hosted) environment. The flag has the following effects: + +* the ``__STDC_HOSTED__`` predefined macro will expand to ``0``, +* builtin functions are disabled (``-fno-builtins``), +* unwind tables are disabled (``fno-asynchronous-unwind-tables -fno-unwind-tables``), and +* allows ``main`` to be used as a regular symbol. + +A freestanding environment is not one which has no C standard library support. ---------------- efriedma-quic wrote:
If the optimizations/warnings disabled by -fno-builtin turn out to be an issue, we can consider adding some additional flag which considers some functions builtin, or something like that. But we'll have to be careful how we expose it: people don't want to be on the treadmill of messing with their environment every time the C committee decides to expand the list of required functions for freestanding implementations. I think it makes sense to specifically call out memcpy/memmove/memset because calls to them can show up even if you don't explicitly write them. https://github.com/llvm/llvm-project/pull/132232 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
