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C backend generated code triggers warnings #19467
Description
Zig Version
0.12.0-dev.3493+3661133f9
Steps to Reproduce and Observed Behavior
Run the C behavior tests outside of zig build test-behavior:
$ stage4/bin/zig test ../test/behavior.zig -ofmt=c -lc
/home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c:65265:5: error: incompatible pointer types assigning to 'void (*)(void)' from 'uint8_t (*)[4]' (aka 'unsigned char (*)[4]')
t0 = &behavior_cast_global_array__1596;
^~~~
/home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c:133807:11: error: incompatible pointer types passing 'struct A__11025 *' to parameter of type 'struct A__11021 *'
issue529(((struct A__11025 *)(uintptr_t)0x0ul));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c:20713:43: note: passing argument to parameter here
zig_extern void issue529(struct A__11021 *);
^
/home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c:133809:11: error: incompatible pointer types passing 'struct A__11026 *' to parameter of type 'struct A__11021 *'
issue529(((struct A__11026 *)(uintptr_t)0x0ul));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c:20713:43: note: passing argument to parameter here
zig_extern void issue529(struct A__11021 *);
^
/home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c:154728:64: error: taking address of packed member 'data' of class or structure 'test_under_2daligned_20struct_20field_S__11770' may result in an unaligned pointer value
t6 = (union test_under_2daligned_20struct_20field_U__11769 *)&t4.data;
^~~~
/home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c:197605:47: error: incompatible function pointer types initializing 'void (*)(int, const struct siginfo_t__struct_7163__7163 *, void *)' with an expression of type 'void (*)(int32_t, const struct siginfo_t__struct_7163__7163 *, const void *)' (aka 'void (*)(int, const struct siginfo_t__struct_7163__7163 *, const void *)')
t0 = (struct Sigaction__7159){{ .sigaction = &debug_handleSegfaultPosix__236 },{UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0),UINT32_C(0)},2415919108u,((void (*)(void))(uintptr_t)0x0ul)};
^~
error: the following test command failed with exit code 1:
/home/andy/dev2/zig/build-release/stage4/bin/zig run -I /home/andy/dev2/zig/lib -lc /home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c
It works if I manually silence these errors:
stage4/bin/zig cc -o test -I /home/andy/dev2/zig/lib -lc /home/andy/dev2/zig/zig-cache/o/6bfbca337d5fc3c5fed111b5c0ce840e/test.c -Wno-incompatible-function-pointer-types
Expected Behavior
No warning suppression lines should be required:
Lines 1166 to 1181 in 3661133
Activity
jacobly0 commentedon Mar 31, 2024
Some of these warnings are fixed by #19470, and some of these warnings come from pretty questionable zig code that I can't even begin to imagine a way to work around. Note that the only actual error here is also fixed by #19470, so once that is merged, the
zig testcommand will no longer fail.mlugg commentedon Dec 6, 2024
Here's another warning which the C backend can trigger, and which seems not to be excluded by the compiler test suite's cflags right now. I think this is
-Wtautological-compare.