One strategy employed by libbpf to guess the pointer size is by finding
the size of "unsigned long" type. This is achieved by looking for a type
of with the expected name and checking its size.
Unfortunately, the C syntax is friendlier to humans than to computers
as there is some variety in how such a type can be named. Specifically,
gcc and clang do not use the same names for integer types in debug info:
- clang uses "unsigned long"
- gcc uses "long unsigned int"
Lookup all the names for such a type so that libbpf can hope to find the
information it wants.
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220524094447.332186-1-douglas.raillard@arm.com
static int determine_ptr_size(const struct btf *btf)
{
+ static const char * const long_aliases[] = {
+ "long",
+ "long int",
+ "int long",
+ "unsigned long",
+ "long unsigned",
+ "unsigned long int",
+ "unsigned int long",
+ "long unsigned int",
+ "long int unsigned",
+ "int unsigned long",
+ "int long unsigned",
+ };
const struct btf_type *t;
const char *name;
- int i, n;
+ int i, j, n;
if (btf->base_btf && btf->base_btf->ptr_sz > 0)
return btf->base_btf->ptr_sz;
if (!btf_is_int(t))
continue;
+ if (t->size != 4 && t->size != 8)
+ continue;
+
name = btf__name_by_offset(btf, t->name_off);
if (!name)
continue;
- if (strcmp(name, "long int") == 0 ||
- strcmp(name, "long unsigned int") == 0) {
- if (t->size != 4 && t->size != 8)
- continue;
- return t->size;
+ for (j = 0; j < ARRAY_SIZE(long_aliases); j++) {
+ if (strcmp(name, long_aliases[j]) == 0)
+ return t->size;
}
}