Hi!
The following testcase ICEs in cpp_sys_macro_p, because cpp_sys_macro_p
is called for a builtin macro which doesn't use node->value.macro union
member but a different one and so dereferencing it ICEs.
As the testcase is distilled from contemporary glibc headers, it means
basically -Wtraditional now ICEs on almost everything.
The fix can be either the patch below, return false for builtin macros,
or we could instead return true for builtin macros and adjust the
function comment, or the fix could be also (untested):
--- libcpp/expr.c 2021-05-07 10:34:46.345122608 +0200
+++ libcpp/expr.c 2021-08-12 09:54:01.837556365 +0200
@@ -783,13 +783,13 @@ cpp_classify_number (cpp_reader *pfile,
/* Traditional C only accepted the 'L' suffix.
Suppress warning about 'LL' with -Wno-long-long. */
- if (CPP_WTRADITIONAL (pfile) && ! cpp_sys_macro_p (pfile))
+ if (CPP_WTRADITIONAL (pfile))
{
int u_or_i = (result & (CPP_N_UNSIGNED|CPP_N_IMAGINARY));
int large = (result & CPP_N_WIDTH) == CPP_N_LARGE
&& CPP_OPTION (pfile, cpp_warn_long_long);
- if (u_or_i || large)
+ if ((u_or_i || large) && ! cpp_sys_macro_p (pfile))
cpp_warning_with_line (pfile, large ? CPP_W_LONG_LONG :
CPP_W_TRADITIONAL,
virtual_location, 0,
"traditional C rejects the \"%.*s\" suffix",
The builtin macros at least currently don't add any suffixes
or numbers -Wtraditional would like to warn about. For floating
point suffixes, -Wtraditional calls cpp_sys_macro_p only right
away before emitting the warning, but in the above case the ICE
is because cpp_sys_macro_p is called even if the number doesn't
have any suffixes (that is I think always for builtin macros
right now).
Bootstrapped/regtested on x86_64-linux and i686-linux.
Ok for trunk, or do you prefer to return true for builtin
macros from cpp_sys_macro_p instead, and/or do you want the
above cpp_classify_number change (which can be done either
alone or in addition to some cpp_sys_macro_p change)?
2021-08-12 Jakub Jelinek <ja...@redhat.com>
PR preprocessor/101638
* macro.c (cpp_sys_macro_p): Return false instead of
crashing on builtin macros.
* gcc.dg/cpp/pr101638.c: New test.
--- libcpp/macro.c.jj 2021-07-20 17:03:08.036449892 +0200
+++ libcpp/macro.c 2021-08-11 20:50:11.212662720 +0200
@@ -3127,7 +3127,10 @@ cpp_sys_macro_p (cpp_reader *pfile)
else
node = pfile->context->c.macro;
- return node && node->value.macro && node->value.macro->syshdr;
+ return (node
+ && cpp_user_macro_p (node)
+ && node->value.macro
+ && node->value.macro->syshdr);
}
/* Read each token in, until end of the current file. Directives are
--- gcc/testsuite/gcc.dg/cpp/pr101638.c.jj 2021-08-11 20:53:04.785289640
+0200
+++ gcc/testsuite/gcc.dg/cpp/pr101638.c 2021-08-11 20:52:36.086682006 +0200
@@ -0,0 +1,7 @@
+/* PR preprocessor/101638 */
+/* { dg-do preprocess } */
+/* { dg-options "-Wtraditional" } */
+
+#define foo(attr) __has_attribute(attr)
+#if foo(__deprecated__)
+#endif
Jakub
