On 7/30/24 15:26, Jonathan M. Wilbur wrote:
Hello,
I pushed a commit (c85eface68940368f696807e97ac7d707e8a73eb) that
treats undefined macro invocations as undefined. Previously, if
"WUMBO" were undefined, a macro invocation such as "WUMBO(O_RDONLY)"
would evaluate to "0(0)" and the compiler would report this as a
syntax error. Now, any undefined macro invocation (with parameters)
will just evaluated to 0 and the parameters will be ignored.
I created this changed based on a real-world need: nolibc (included
with the Linux kernel source) makes use of the __has_attribute macro,
which seems to be built-in to GCC, but was defined in such a way in
nolibc where it would not be defined everywhere it was used. This
meant that compiling nolibc with
TinyCC would treat __has_attribute as 0 and its parameters as (0), as
described above.
You could argue that this is undesirable behavior. I didn't know I
could just push right to the mob branch, so I was expecting a little
more debate and review before submitting.
The patch is attached.
Some comments:
You probably did not run 'make test'.
Tests should go into 'tests/tests2' directory.
If I compile the 'tests/undef_func_macro.c' code with gcc I get:
tests/undef_func_macro.c: In function 'main':
tests/undef_func_macro.c:4:12: error: missing binary operator before
token "("
4 | #if WUMBOED(WUMBO)
| ^
tests/undef_func_macro.c:8:43: error: missing binary operator before
token "("
8 | #if WUMBO && defined(WUMBOLOGY) || WUMBOED(WUMBO) && !WUMBOLOGY
| ^
tests/undef_func_macro.c:10:45: error: missing binary operator before
token "("
10 | #elif WUMBO && defined(WUMBOLOGY) || WUMBOED(WUMBO) && !WUMBOLOGY
|
So gcc does not support this.
Looks like you have to revert the patch.
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