================
@@ -1165,7 +1165,112 @@ void
Sema::checkFortifiedBuiltinMemoryFunction(FunctionDecl *FD,
unsigned BuiltinID = UseDecl->getBuiltinID(/*ConsiderWrappers=*/true);
- if (!BuiltinID)
+ // Some libc I/O functions are intentionally not Clang builtins:
+ // * "read", "write", "readlink", "readlinkat", and "getcwd" are common
+ // identifiers (or names that appear in asm-label wrappers); declaring
+ // them as builtins triggers -Wincompatible-library-redeclaration on
+ // harmless local declarations (an error under -Werror).
+ // * pread/pwrite prototypes use off_t, whose width is platform- and
+ // macro-dependent (notably _FILE_OFFSET_BITS); a fixed builtin signature
+ // would clash with the system header on some targets.
+ // Recognize them by name, but only after checking the full POSIX prototype
+ // so that an unrelated function happening to share the name is not
+ // diagnosed as if it were the libc function.
+ enum class LibCDispatch {
+ None,
+ Read,
+ Write,
+ PRead,
+ PWrite,
+ ReadLink,
+ ReadLinkAt,
+ GetCWD,
+ };
+ LibCDispatch LibC = LibCDispatch::None;
+ StringRef LibCName;
+ if (!BuiltinID && FD->isExternC() && FD->getIdentifier() &&
----------------
nuclearcat wrote:
yeah good point on the integer thing, sameUnqualifiedType || both-integer is
plenty given the name match already pins us to POSIX intent. dropping the
SSizeT/OffT/Off64T predicates, much cleaner.
re mismatched decls: was initially defensive, but i went looking and it's
actually not hypothetical. newlib-style syscall stubs do extern "C" int
read(int, void*, size_t) all over the place in several projects.
I added test_pread64_newlib_buffer / test_pwrite64_newlib_buffer to
warn-fortify-source-prototype-gate.c, just in case.
Checking the code now, will push in an hour - thanks a lot for the very helpful
review!
https://github.com/llvm/llvm-project/pull/196499
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