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analyzer: fix -Wanalyzer-va-list-exhausted false +ve on va_arg in subroutine [PR106383] 

gcc/analyzer/ChangeLog:
	PR analyzer/106383
	* varargs.cc (region_model::impl_call_va_arg): When determining if
	we're doing interprocedural analysis, use the stack depth of the
	frame in which va_start was called, rather than the current stack
	depth.

gcc/testsuite/ChangeLog:
	PR analyzer/106383
	* gcc.dg/analyzer/stdarg-3.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>
This commit is contained in:
David Malcolm 2022-07-21 17:29:26 -04:00
parent 633e992058
commit b852aa7f26
2 changed files with 59 additions and 2 deletions
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4
gcc/analyzer/varargs.cc
View File

@ -971,7 +971,7 @@ region_model::impl_call_va_arg (const call_details &cd)
const frame_region *frame_reg = arg_reg->get_frame_region ();
unsigned next_arg_idx = arg_reg->get_index ();
if (get_stack_depth () > 1)
if (frame_reg->get_stack_depth () > 1)
{
/* The interprocedural case: the called frame will have been
populated with any variadic aruguments.
@ -1009,7 +1009,7 @@ region_model::impl_call_va_arg (const call_details &cd)
any specific var_arg_regions populated within it.
We already have a conjured_svalue for the result, so leave
it untouched. */
gcc_assert (get_stack_depth () == 1);
gcc_assert (frame_reg->get_stack_depth () == 1);
}
if (saw_problem)

57
gcc/testsuite/gcc.dg/analyzer/stdarg-3.c Normal file
View File

@ -0,0 +1,57 @@
typedef __builtin_va_list va_list;
struct printf_spec {
unsigned int type;
};
int
format_decode(const char *fmt, struct printf_spec *spec);
static int vbin_printf(const char *fmt, va_list args) {
struct printf_spec spec;
int width = 0;
while (*fmt) {
int read = format_decode(fmt, &spec);
fmt += read;
switch (spec.type) {
case 0:
break;
case 1:
width = __builtin_va_arg(args, int); /* { dg-bogus "-Wanalyzer-va-list-exhausted" } */
break;
}
}
return width;
}
int bprintf(const char *fmt, ...) {
va_list args;
int ret;
__builtin_va_start(args, fmt);
ret = vbin_printf(fmt, args);
__builtin_va_end(args);
return ret;
}
static int called_by_test_2 (va_list args)
{
return __builtin_va_arg(args, int); /* { dg-bogus "-Wanalyzer-va-list-exhausted" } */
}
int test_2 (const char *fmt, ...)
{
va_list args;
int ret;
__builtin_va_start (args, fmt);
ret = called_by_test_2 (args);
__builtin_va_end (args);
return ret;
}