Author: Christopher Di Bella Date: 2021-03-04T17:00:54Z New Revision: 9830901b341cfb884cdef00e0335c6e3e62d107a
URL: https://github.com/llvm/llvm-project/commit/9830901b341cfb884cdef00e0335c6e3e62d107a DIFF: https://github.com/llvm/llvm-project/commit/9830901b341cfb884cdef00e0335c6e3e62d107a.diff LOG: [clang] removes check against integral-to-pointer conversion... ... unless it's a literal D94640 was a bit too aggressive in its analysis, considering integers representing valid addresses as invalid. This change rolls back some of the check, so that only the most obvious case is still flagged. Before: ```cpp free((void*)1000); // literal converted to `void*`: warning good free((void*)an_int); // `int` object converted to `void*`: warning might // be a false positive ``` After ```cpp free((void*)1000); // literal converted to `void*`: warning good free((void*)an_int); // doesn't warn ``` Differential Revision: https://reviews.llvm.org/D97512 Added: Modified: clang/lib/Sema/SemaChecking.cpp clang/test/Analysis/free.c clang/test/Analysis/free.cpp Removed: ################################################################################ diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index 7e6dd354caace..22dd634c5031a 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -10316,11 +10316,18 @@ void CheckFreeArgumentsCast(Sema &S, const std::string &CalleeName, const CastExpr *Cast) { SmallString<128> SizeString; llvm::raw_svector_ostream OS(SizeString); + + clang::CastKind Kind = Cast->getCastKind(); + if (Kind == clang::CK_BitCast && + !Cast->getSubExpr()->getType()->isFunctionPointerType()) + return; + if (Kind == clang::CK_IntegralToPointer && + !isa<IntegerLiteral>( + Cast->getSubExpr()->IgnoreParenImpCasts()->IgnoreParens())) + return; + switch (Cast->getCastKind()) { case clang::CK_BitCast: - if (!Cast->getSubExpr()->getType()->isFunctionPointerType()) - return; - LLVM_FALLTHROUGH; case clang::CK_IntegralToPointer: case clang::CK_FunctionToPointerDecay: OS << '\''; diff --git a/clang/test/Analysis/free.c b/clang/test/Analysis/free.c index 84d53472158cd..59767b5917d79 100644 --- a/clang/test/Analysis/free.c +++ b/clang/test/Analysis/free.c @@ -108,3 +108,11 @@ void t17(void) { // expected-warning@-1{{Argument to free() is the address of the function 'iptr', which is not memory allocated by malloc()}} // expected-warning@-2{{attempt to call free on non-heap object 'iptr'}} } + +struct S { + const char* p; +}; + +void t18 (struct S s) { + free((void*)(unsigned long long)s.p); // no warning +} diff --git a/clang/test/Analysis/free.cpp b/clang/test/Analysis/free.cpp index 2559770d6ddb7..85b0935a51992 100644 --- a/clang/test/Analysis/free.cpp +++ b/clang/test/Analysis/free.cpp @@ -208,3 +208,39 @@ void t17b (char **x, int offset) { // Unknown value std::free(x[offset]); // no-warning } + +struct S { + const char* p; +}; + +void t18_C_style_C_style_free (S s) { + free((void*)(unsigned long long)s.p); // no warning +} + +void t18_C_style_C_style_std_free (S s) { + std::free((void*)(unsigned long long)s.p); // no warning +} + +void t18_C_style_reinterpret_free (S s) { + free((void*)reinterpret_cast<unsigned long long>(s.p)); // no warning +} + +void t18_C_style_reinterpret_std_free (S s) { + std::free((void*)reinterpret_cast<unsigned long long>(s.p)); // no warning +} + +void t18_reinterpret_C_style_free (S s) { + free(reinterpret_cast<void*>((unsigned long long)(s.p))); // no warning +} + +void t18_reinterpret_C_style_std_free (S s) { + std::free(reinterpret_cast<void*>((unsigned long long)(s.p))); // no warning +} + +void t18_reinterpret_reinterpret_free (S s) { + free(reinterpret_cast<void*>(reinterpret_cast<unsigned long long>(s.p))); // no warning +} + +void t18_reinterpret_reinterpret_std_free (S s) { + std::free(reinterpret_cast<void*>(reinterpret_cast<unsigned long long>(s.p))); // no warning +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
