https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95485
Bug ID: 95485 Summary: missing warning writing into function text Product: gcc Version: 10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: msebor at gcc dot gnu.org Target Milestone: --- GCC doesn't diagnose attempts to write into functions, even though those will in all likelihood crash with a SIGBUS at runtime. For example, in the following snippet the destination of the memset call is a function rather than the memory it was called to obtain. The memset call should be diagnosed. $ cat z.c && gcc -O2 -S -Wall -fdump-tree-optimized=/dev/stdout z.c typedef void* F (int); void* f (F *p) { void *q = p (32); // allocate memory __builtin_memset (p, 0, 32); // zero out -- whoops! -- writing to a function return q; // return "clear" memory } ;; Function f (f, funcdef_no=0, decl_uid=1933, cgraph_uid=1, symbol_order=0) f (void * (*<T322>) (int) p) { void * q; <bb 2> [local count: 1073741824]: q_4 = p_2(D) (32); __builtin_memset (p_2(D), 0, 32); return q_4; } Two compilers on Godbolt diagnose the code: Visual C++: z.c(8): warning C4152: nonstandard extension, function/data pointer conversion in expression and the Small Device C Compiler (SDCC): x.c:8: warning 244: pointer types incompatible from type 'void generic* function ( int fixed) code* fixed' to type 'void generic* fixed'