From 610cd93b44ce1e7323878ef5f7b23dc10c7d45b7 Mon Sep 17 00:00:00 2001 From: Douglas Raillard Date: Tue, 24 May 2022 10:44:47 +0100 Subject: [PATCH] libbpf: Fix determine_ptr_size() guessing 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 Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20220524094447.332186-1-douglas.raillard@arm.com --- tools/lib/bpf/btf.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index bb1e06e..3d6c30d9 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -472,9 +472,22 @@ const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id) 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; @@ -485,15 +498,16 @@ static int determine_ptr_size(const struct btf *btf) 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; } } -- 2.7.4