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![Andrii Nakryiko](/assets/img/avatar_default.png)
Handle a GCC quirk of emitting extra volatile modifier in DWARF (and
subsequently preserved in BTF by pahole) for function pointers marked as
__attribute__((noreturn)). This was the way to mark such functions before GCC
2.5 added noreturn attribute. Drop such func_proto modifiers, similarly to how
it's done for array (also to handle GCC quirk/bug).
Such volatile attribute is emitted by GCC only, so existing selftests can't
express such test. Simple repro is like this (compiled with GCC + BTF
generated by pahole):
struct my_struct {
void __attribute__((noreturn)) (*fn)(int);
};
struct my_struct a;
Without this fix, output will be:
struct my_struct {
voidvolatile (*fn)(int);
};
With the fix:
struct my_struct {
void (*fn)(int);
};
Fixes: 351131b51c
("libbpf: add btf_dump API for BTF-to-C conversion")
Reported-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/bpf/20200610052335.2862559-1-andriin@fb.com
1386 lines
38 KiB
C
1386 lines
38 KiB
C
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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/*
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* BTF-to-C type converter.
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*
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* Copyright (c) 2019 Facebook
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*/
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <linux/err.h>
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#include <linux/btf.h>
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#include "btf.h"
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#include "hashmap.h"
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#include "libbpf.h"
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#include "libbpf_internal.h"
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/* make sure libbpf doesn't use kernel-only integer typedefs */
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#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
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static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t";
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static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1;
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static const char *pfx(int lvl)
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{
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return lvl >= PREFIX_CNT ? PREFIXES : &PREFIXES[PREFIX_CNT - lvl];
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}
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enum btf_dump_type_order_state {
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NOT_ORDERED,
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ORDERING,
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ORDERED,
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};
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enum btf_dump_type_emit_state {
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NOT_EMITTED,
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EMITTING,
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EMITTED,
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};
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/* per-type auxiliary state */
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struct btf_dump_type_aux_state {
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/* topological sorting state */
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enum btf_dump_type_order_state order_state: 2;
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/* emitting state used to determine the need for forward declaration */
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enum btf_dump_type_emit_state emit_state: 2;
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/* whether forward declaration was already emitted */
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__u8 fwd_emitted: 1;
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/* whether unique non-duplicate name was already assigned */
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__u8 name_resolved: 1;
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/* whether type is referenced from any other type */
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__u8 referenced: 1;
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};
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struct btf_dump {
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const struct btf *btf;
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const struct btf_ext *btf_ext;
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btf_dump_printf_fn_t printf_fn;
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struct btf_dump_opts opts;
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/* per-type auxiliary state */
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struct btf_dump_type_aux_state *type_states;
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/* per-type optional cached unique name, must be freed, if present */
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const char **cached_names;
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/* topo-sorted list of dependent type definitions */
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__u32 *emit_queue;
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int emit_queue_cap;
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int emit_queue_cnt;
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/*
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* stack of type declarations (e.g., chain of modifiers, arrays,
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* funcs, etc)
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*/
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__u32 *decl_stack;
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int decl_stack_cap;
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int decl_stack_cnt;
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/* maps struct/union/enum name to a number of name occurrences */
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struct hashmap *type_names;
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/*
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* maps typedef identifiers and enum value names to a number of such
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* name occurrences
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*/
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struct hashmap *ident_names;
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};
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static size_t str_hash_fn(const void *key, void *ctx)
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{
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const char *s = key;
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size_t h = 0;
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while (*s) {
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h = h * 31 + *s;
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s++;
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}
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return h;
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}
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static bool str_equal_fn(const void *a, const void *b, void *ctx)
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{
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return strcmp(a, b) == 0;
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}
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static const char *btf_name_of(const struct btf_dump *d, __u32 name_off)
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{
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return btf__name_by_offset(d->btf, name_off);
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}
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static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...)
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{
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va_list args;
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va_start(args, fmt);
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d->printf_fn(d->opts.ctx, fmt, args);
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va_end(args);
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}
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static int btf_dump_mark_referenced(struct btf_dump *d);
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struct btf_dump *btf_dump__new(const struct btf *btf,
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const struct btf_ext *btf_ext,
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const struct btf_dump_opts *opts,
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btf_dump_printf_fn_t printf_fn)
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{
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struct btf_dump *d;
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int err;
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d = calloc(1, sizeof(struct btf_dump));
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if (!d)
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return ERR_PTR(-ENOMEM);
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d->btf = btf;
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d->btf_ext = btf_ext;
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d->printf_fn = printf_fn;
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d->opts.ctx = opts ? opts->ctx : NULL;
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d->type_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
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if (IS_ERR(d->type_names)) {
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err = PTR_ERR(d->type_names);
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d->type_names = NULL;
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goto err;
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}
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d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
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if (IS_ERR(d->ident_names)) {
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err = PTR_ERR(d->ident_names);
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d->ident_names = NULL;
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goto err;
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}
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d->type_states = calloc(1 + btf__get_nr_types(d->btf),
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sizeof(d->type_states[0]));
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if (!d->type_states) {
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err = -ENOMEM;
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goto err;
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}
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d->cached_names = calloc(1 + btf__get_nr_types(d->btf),
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sizeof(d->cached_names[0]));
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if (!d->cached_names) {
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err = -ENOMEM;
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goto err;
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}
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/* VOID is special */
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d->type_states[0].order_state = ORDERED;
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d->type_states[0].emit_state = EMITTED;
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/* eagerly determine referenced types for anon enums */
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err = btf_dump_mark_referenced(d);
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if (err)
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goto err;
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return d;
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err:
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btf_dump__free(d);
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return ERR_PTR(err);
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}
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void btf_dump__free(struct btf_dump *d)
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{
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int i, cnt;
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if (!d)
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return;
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free(d->type_states);
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if (d->cached_names) {
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/* any set cached name is owned by us and should be freed */
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for (i = 0, cnt = btf__get_nr_types(d->btf); i <= cnt; i++) {
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if (d->cached_names[i])
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free((void *)d->cached_names[i]);
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}
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}
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free(d->cached_names);
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free(d->emit_queue);
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free(d->decl_stack);
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hashmap__free(d->type_names);
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hashmap__free(d->ident_names);
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free(d);
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}
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static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr);
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static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id);
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/*
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* Dump BTF type in a compilable C syntax, including all the necessary
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* dependent types, necessary for compilation. If some of the dependent types
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* were already emitted as part of previous btf_dump__dump_type() invocation
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* for another type, they won't be emitted again. This API allows callers to
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* filter out BTF types according to user-defined criterias and emitted only
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* minimal subset of types, necessary to compile everything. Full struct/union
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* definitions will still be emitted, even if the only usage is through
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* pointer and could be satisfied with just a forward declaration.
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*
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* Dumping is done in two high-level passes:
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* 1. Topologically sort type definitions to satisfy C rules of compilation.
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* 2. Emit type definitions in C syntax.
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*
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* Returns 0 on success; <0, otherwise.
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*/
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int btf_dump__dump_type(struct btf_dump *d, __u32 id)
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{
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int err, i;
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if (id > btf__get_nr_types(d->btf))
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return -EINVAL;
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d->emit_queue_cnt = 0;
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err = btf_dump_order_type(d, id, false);
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if (err < 0)
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return err;
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for (i = 0; i < d->emit_queue_cnt; i++)
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btf_dump_emit_type(d, d->emit_queue[i], 0 /*top-level*/);
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return 0;
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}
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/*
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* Mark all types that are referenced from any other type. This is used to
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* determine top-level anonymous enums that need to be emitted as an
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* independent type declarations.
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* Anonymous enums come in two flavors: either embedded in a struct's field
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* definition, in which case they have to be declared inline as part of field
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* type declaration; or as a top-level anonymous enum, typically used for
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* declaring global constants. It's impossible to distinguish between two
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* without knowning whether given enum type was referenced from other type:
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* top-level anonymous enum won't be referenced by anything, while embedded
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* one will.
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*/
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static int btf_dump_mark_referenced(struct btf_dump *d)
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{
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int i, j, n = btf__get_nr_types(d->btf);
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const struct btf_type *t;
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__u16 vlen;
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for (i = 1; i <= n; i++) {
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t = btf__type_by_id(d->btf, i);
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vlen = btf_vlen(t);
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switch (btf_kind(t)) {
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case BTF_KIND_INT:
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case BTF_KIND_ENUM:
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case BTF_KIND_FWD:
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break;
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case BTF_KIND_VOLATILE:
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case BTF_KIND_CONST:
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case BTF_KIND_RESTRICT:
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case BTF_KIND_PTR:
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case BTF_KIND_TYPEDEF:
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case BTF_KIND_FUNC:
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case BTF_KIND_VAR:
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d->type_states[t->type].referenced = 1;
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break;
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case BTF_KIND_ARRAY: {
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const struct btf_array *a = btf_array(t);
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d->type_states[a->index_type].referenced = 1;
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d->type_states[a->type].referenced = 1;
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break;
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}
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case BTF_KIND_STRUCT:
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case BTF_KIND_UNION: {
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const struct btf_member *m = btf_members(t);
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for (j = 0; j < vlen; j++, m++)
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d->type_states[m->type].referenced = 1;
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break;
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}
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case BTF_KIND_FUNC_PROTO: {
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const struct btf_param *p = btf_params(t);
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for (j = 0; j < vlen; j++, p++)
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d->type_states[p->type].referenced = 1;
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break;
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}
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case BTF_KIND_DATASEC: {
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const struct btf_var_secinfo *v = btf_var_secinfos(t);
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for (j = 0; j < vlen; j++, v++)
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d->type_states[v->type].referenced = 1;
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break;
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}
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default:
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return -EINVAL;
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}
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}
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return 0;
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}
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static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id)
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{
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__u32 *new_queue;
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size_t new_cap;
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if (d->emit_queue_cnt >= d->emit_queue_cap) {
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new_cap = max(16, d->emit_queue_cap * 3 / 2);
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new_queue = realloc(d->emit_queue,
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new_cap * sizeof(new_queue[0]));
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if (!new_queue)
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return -ENOMEM;
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d->emit_queue = new_queue;
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d->emit_queue_cap = new_cap;
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}
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d->emit_queue[d->emit_queue_cnt++] = id;
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return 0;
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}
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/*
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* Determine order of emitting dependent types and specified type to satisfy
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* C compilation rules. This is done through topological sorting with an
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* additional complication which comes from C rules. The main idea for C is
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* that if some type is "embedded" into a struct/union, it's size needs to be
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* known at the time of definition of containing type. E.g., for:
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*
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* struct A {};
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* struct B { struct A x; }
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*
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* struct A *HAS* to be defined before struct B, because it's "embedded",
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* i.e., it is part of struct B layout. But in the following case:
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*
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* struct A;
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* struct B { struct A *x; }
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* struct A {};
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*
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* it's enough to just have a forward declaration of struct A at the time of
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* struct B definition, as struct B has a pointer to struct A, so the size of
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* field x is known without knowing struct A size: it's sizeof(void *).
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*
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* Unfortunately, there are some trickier cases we need to handle, e.g.:
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*
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* struct A {}; // if this was forward-declaration: compilation error
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* struct B {
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* struct { // anonymous struct
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* struct A y;
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* } *x;
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* };
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*
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* In this case, struct B's field x is a pointer, so it's size is known
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* regardless of the size of (anonymous) struct it points to. But because this
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* struct is anonymous and thus defined inline inside struct B, *and* it
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* embeds struct A, compiler requires full definition of struct A to be known
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* before struct B can be defined. This creates a transitive dependency
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* between struct A and struct B. If struct A was forward-declared before
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* struct B definition and fully defined after struct B definition, that would
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* trigger compilation error.
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*
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* All this means that while we are doing topological sorting on BTF type
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* graph, we need to determine relationships between different types (graph
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* nodes):
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* - weak link (relationship) between X and Y, if Y *CAN* be
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* forward-declared at the point of X definition;
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* - strong link, if Y *HAS* to be fully-defined before X can be defined.
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*
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* The rule is as follows. Given a chain of BTF types from X to Y, if there is
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* BTF_KIND_PTR type in the chain and at least one non-anonymous type
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* Z (excluding X, including Y), then link is weak. Otherwise, it's strong.
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* Weak/strong relationship is determined recursively during DFS traversal and
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* is returned as a result from btf_dump_order_type().
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*
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* btf_dump_order_type() is trying to avoid unnecessary forward declarations,
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* but it is not guaranteeing that no extraneous forward declarations will be
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* emitted.
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*
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* To avoid extra work, algorithm marks some of BTF types as ORDERED, when
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* it's done with them, but not for all (e.g., VOLATILE, CONST, RESTRICT,
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* ARRAY, FUNC_PROTO), as weak/strong semantics for those depends on the
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* entire graph path, so depending where from one came to that BTF type, it
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* might cause weak or strong ordering. For types like STRUCT/UNION/INT/ENUM,
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* once they are processed, there is no need to do it again, so they are
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* marked as ORDERED. We can mark PTR as ORDERED as well, as it semi-forces
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* weak link, unless subsequent referenced STRUCT/UNION/ENUM is anonymous. But
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* in any case, once those are processed, no need to do it again, as the
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* result won't change.
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*
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* Returns:
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* - 1, if type is part of strong link (so there is strong topological
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* ordering requirements);
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* - 0, if type is part of weak link (so can be satisfied through forward
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* declaration);
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* - <0, on error (e.g., unsatisfiable type loop detected).
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*/
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static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
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{
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/*
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* Order state is used to detect strong link cycles, but only for BTF
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* kinds that are or could be an independent definition (i.e.,
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* stand-alone fwd decl, enum, typedef, struct, union). Ptrs, arrays,
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* func_protos, modifiers are just means to get to these definitions.
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* Int/void don't need definitions, they are assumed to be always
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* properly defined. We also ignore datasec, var, and funcs for now.
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* So for all non-defining kinds, we never even set ordering state,
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* for defining kinds we set ORDERING and subsequently ORDERED if it
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* forms a strong link.
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*/
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struct btf_dump_type_aux_state *tstate = &d->type_states[id];
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const struct btf_type *t;
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__u16 vlen;
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int err, i;
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/* return true, letting typedefs know that it's ok to be emitted */
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if (tstate->order_state == ORDERED)
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return 1;
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t = btf__type_by_id(d->btf, id);
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if (tstate->order_state == ORDERING) {
|
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/* type loop, but resolvable through fwd declaration */
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if (btf_is_composite(t) && through_ptr && t->name_off != 0)
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return 0;
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pr_warn("unsatisfiable type cycle, id:[%u]\n", id);
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return -ELOOP;
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}
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|
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switch (btf_kind(t)) {
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case BTF_KIND_INT:
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tstate->order_state = ORDERED;
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return 0;
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|
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case BTF_KIND_PTR:
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err = btf_dump_order_type(d, t->type, true);
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tstate->order_state = ORDERED;
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return err;
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case BTF_KIND_ARRAY:
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return btf_dump_order_type(d, btf_array(t)->type, through_ptr);
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|
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case BTF_KIND_STRUCT:
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case BTF_KIND_UNION: {
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const struct btf_member *m = btf_members(t);
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/*
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* struct/union is part of strong link, only if it's embedded
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* (so no ptr in a path) or it's anonymous (so has to be
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* defined inline, even if declared through ptr)
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*/
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if (through_ptr && t->name_off != 0)
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return 0;
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tstate->order_state = ORDERING;
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|
|
vlen = btf_vlen(t);
|
|
for (i = 0; i < vlen; i++, m++) {
|
|
err = btf_dump_order_type(d, m->type, false);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
if (t->name_off != 0) {
|
|
err = btf_dump_add_emit_queue_id(d, id);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
tstate->order_state = ORDERED;
|
|
return 1;
|
|
}
|
|
case BTF_KIND_ENUM:
|
|
case BTF_KIND_FWD:
|
|
/*
|
|
* non-anonymous or non-referenced enums are top-level
|
|
* declarations and should be emitted. Same logic can be
|
|
* applied to FWDs, it won't hurt anyways.
|
|
*/
|
|
if (t->name_off != 0 || !tstate->referenced) {
|
|
err = btf_dump_add_emit_queue_id(d, id);
|
|
if (err)
|
|
return err;
|
|
}
|
|
tstate->order_state = ORDERED;
|
|
return 1;
|
|
|
|
case BTF_KIND_TYPEDEF: {
|
|
int is_strong;
|
|
|
|
is_strong = btf_dump_order_type(d, t->type, through_ptr);
|
|
if (is_strong < 0)
|
|
return is_strong;
|
|
|
|
/* typedef is similar to struct/union w.r.t. fwd-decls */
|
|
if (through_ptr && !is_strong)
|
|
return 0;
|
|
|
|
/* typedef is always a named definition */
|
|
err = btf_dump_add_emit_queue_id(d, id);
|
|
if (err)
|
|
return err;
|
|
|
|
d->type_states[id].order_state = ORDERED;
|
|
return 1;
|
|
}
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_RESTRICT:
|
|
return btf_dump_order_type(d, t->type, through_ptr);
|
|
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
const struct btf_param *p = btf_params(t);
|
|
bool is_strong;
|
|
|
|
err = btf_dump_order_type(d, t->type, through_ptr);
|
|
if (err < 0)
|
|
return err;
|
|
is_strong = err > 0;
|
|
|
|
vlen = btf_vlen(t);
|
|
for (i = 0; i < vlen; i++, p++) {
|
|
err = btf_dump_order_type(d, p->type, through_ptr);
|
|
if (err < 0)
|
|
return err;
|
|
if (err > 0)
|
|
is_strong = true;
|
|
}
|
|
return is_strong;
|
|
}
|
|
case BTF_KIND_FUNC:
|
|
case BTF_KIND_VAR:
|
|
case BTF_KIND_DATASEC:
|
|
d->type_states[id].order_state = ORDERED;
|
|
return 0;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t);
|
|
static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t, int lvl);
|
|
|
|
static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t);
|
|
static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t, int lvl);
|
|
|
|
static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t);
|
|
|
|
static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t, int lvl);
|
|
|
|
/* a local view into a shared stack */
|
|
struct id_stack {
|
|
const __u32 *ids;
|
|
int cnt;
|
|
};
|
|
|
|
static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
|
|
const char *fname, int lvl);
|
|
static void btf_dump_emit_type_chain(struct btf_dump *d,
|
|
struct id_stack *decl_stack,
|
|
const char *fname, int lvl);
|
|
|
|
static const char *btf_dump_type_name(struct btf_dump *d, __u32 id);
|
|
static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id);
|
|
static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
|
|
const char *orig_name);
|
|
|
|
static bool btf_dump_is_blacklisted(struct btf_dump *d, __u32 id)
|
|
{
|
|
const struct btf_type *t = btf__type_by_id(d->btf, id);
|
|
|
|
/* __builtin_va_list is a compiler built-in, which causes compilation
|
|
* errors, when compiling w/ different compiler, then used to compile
|
|
* original code (e.g., GCC to compile kernel, Clang to use generated
|
|
* C header from BTF). As it is built-in, it should be already defined
|
|
* properly internally in compiler.
|
|
*/
|
|
if (t->name_off == 0)
|
|
return false;
|
|
return strcmp(btf_name_of(d, t->name_off), "__builtin_va_list") == 0;
|
|
}
|
|
|
|
/*
|
|
* Emit C-syntax definitions of types from chains of BTF types.
|
|
*
|
|
* High-level handling of determining necessary forward declarations are handled
|
|
* by btf_dump_emit_type() itself, but all nitty-gritty details of emitting type
|
|
* declarations/definitions in C syntax are handled by a combo of
|
|
* btf_dump_emit_type_decl()/btf_dump_emit_type_chain() w/ delegation to
|
|
* corresponding btf_dump_emit_*_{def,fwd}() functions.
|
|
*
|
|
* We also keep track of "containing struct/union type ID" to determine when
|
|
* we reference it from inside and thus can avoid emitting unnecessary forward
|
|
* declaration.
|
|
*
|
|
* This algorithm is designed in such a way, that even if some error occurs
|
|
* (either technical, e.g., out of memory, or logical, i.e., malformed BTF
|
|
* that doesn't comply to C rules completely), algorithm will try to proceed
|
|
* and produce as much meaningful output as possible.
|
|
*/
|
|
static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
|
|
{
|
|
struct btf_dump_type_aux_state *tstate = &d->type_states[id];
|
|
bool top_level_def = cont_id == 0;
|
|
const struct btf_type *t;
|
|
__u16 kind;
|
|
|
|
if (tstate->emit_state == EMITTED)
|
|
return;
|
|
|
|
t = btf__type_by_id(d->btf, id);
|
|
kind = btf_kind(t);
|
|
|
|
if (tstate->emit_state == EMITTING) {
|
|
if (tstate->fwd_emitted)
|
|
return;
|
|
|
|
switch (kind) {
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION:
|
|
/*
|
|
* if we are referencing a struct/union that we are
|
|
* part of - then no need for fwd declaration
|
|
*/
|
|
if (id == cont_id)
|
|
return;
|
|
if (t->name_off == 0) {
|
|
pr_warn("anonymous struct/union loop, id:[%u]\n",
|
|
id);
|
|
return;
|
|
}
|
|
btf_dump_emit_struct_fwd(d, id, t);
|
|
btf_dump_printf(d, ";\n\n");
|
|
tstate->fwd_emitted = 1;
|
|
break;
|
|
case BTF_KIND_TYPEDEF:
|
|
/*
|
|
* for typedef fwd_emitted means typedef definition
|
|
* was emitted, but it can be used only for "weak"
|
|
* references through pointer only, not for embedding
|
|
*/
|
|
if (!btf_dump_is_blacklisted(d, id)) {
|
|
btf_dump_emit_typedef_def(d, id, t, 0);
|
|
btf_dump_printf(d, ";\n\n");
|
|
}
|
|
tstate->fwd_emitted = 1;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
switch (kind) {
|
|
case BTF_KIND_INT:
|
|
tstate->emit_state = EMITTED;
|
|
break;
|
|
case BTF_KIND_ENUM:
|
|
if (top_level_def) {
|
|
btf_dump_emit_enum_def(d, id, t, 0);
|
|
btf_dump_printf(d, ";\n\n");
|
|
}
|
|
tstate->emit_state = EMITTED;
|
|
break;
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_RESTRICT:
|
|
btf_dump_emit_type(d, t->type, cont_id);
|
|
break;
|
|
case BTF_KIND_ARRAY:
|
|
btf_dump_emit_type(d, btf_array(t)->type, cont_id);
|
|
break;
|
|
case BTF_KIND_FWD:
|
|
btf_dump_emit_fwd_def(d, id, t);
|
|
btf_dump_printf(d, ";\n\n");
|
|
tstate->emit_state = EMITTED;
|
|
break;
|
|
case BTF_KIND_TYPEDEF:
|
|
tstate->emit_state = EMITTING;
|
|
btf_dump_emit_type(d, t->type, id);
|
|
/*
|
|
* typedef can server as both definition and forward
|
|
* declaration; at this stage someone depends on
|
|
* typedef as a forward declaration (refers to it
|
|
* through pointer), so unless we already did it,
|
|
* emit typedef as a forward declaration
|
|
*/
|
|
if (!tstate->fwd_emitted && !btf_dump_is_blacklisted(d, id)) {
|
|
btf_dump_emit_typedef_def(d, id, t, 0);
|
|
btf_dump_printf(d, ";\n\n");
|
|
}
|
|
tstate->emit_state = EMITTED;
|
|
break;
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION:
|
|
tstate->emit_state = EMITTING;
|
|
/* if it's a top-level struct/union definition or struct/union
|
|
* is anonymous, then in C we'll be emitting all fields and
|
|
* their types (as opposed to just `struct X`), so we need to
|
|
* make sure that all types, referenced from struct/union
|
|
* members have necessary forward-declarations, where
|
|
* applicable
|
|
*/
|
|
if (top_level_def || t->name_off == 0) {
|
|
const struct btf_member *m = btf_members(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
int i, new_cont_id;
|
|
|
|
new_cont_id = t->name_off == 0 ? cont_id : id;
|
|
for (i = 0; i < vlen; i++, m++)
|
|
btf_dump_emit_type(d, m->type, new_cont_id);
|
|
} else if (!tstate->fwd_emitted && id != cont_id) {
|
|
btf_dump_emit_struct_fwd(d, id, t);
|
|
btf_dump_printf(d, ";\n\n");
|
|
tstate->fwd_emitted = 1;
|
|
}
|
|
|
|
if (top_level_def) {
|
|
btf_dump_emit_struct_def(d, id, t, 0);
|
|
btf_dump_printf(d, ";\n\n");
|
|
tstate->emit_state = EMITTED;
|
|
} else {
|
|
tstate->emit_state = NOT_EMITTED;
|
|
}
|
|
break;
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
const struct btf_param *p = btf_params(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
int i;
|
|
|
|
btf_dump_emit_type(d, t->type, cont_id);
|
|
for (i = 0; i < vlen; i++, p++)
|
|
btf_dump_emit_type(d, p->type, cont_id);
|
|
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
static bool btf_is_struct_packed(const struct btf *btf, __u32 id,
|
|
const struct btf_type *t)
|
|
{
|
|
const struct btf_member *m;
|
|
int align, i, bit_sz;
|
|
__u16 vlen;
|
|
|
|
align = btf__align_of(btf, id);
|
|
/* size of a non-packed struct has to be a multiple of its alignment*/
|
|
if (align && t->size % align)
|
|
return true;
|
|
|
|
m = btf_members(t);
|
|
vlen = btf_vlen(t);
|
|
/* all non-bitfield fields have to be naturally aligned */
|
|
for (i = 0; i < vlen; i++, m++) {
|
|
align = btf__align_of(btf, m->type);
|
|
bit_sz = btf_member_bitfield_size(t, i);
|
|
if (align && bit_sz == 0 && m->offset % (8 * align) != 0)
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* if original struct was marked as packed, but its layout is
|
|
* naturally aligned, we'll detect that it's not packed
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
static int chip_away_bits(int total, int at_most)
|
|
{
|
|
return total % at_most ? : at_most;
|
|
}
|
|
|
|
static void btf_dump_emit_bit_padding(const struct btf_dump *d,
|
|
int cur_off, int m_off, int m_bit_sz,
|
|
int align, int lvl)
|
|
{
|
|
int off_diff = m_off - cur_off;
|
|
int ptr_bits = sizeof(void *) * 8;
|
|
|
|
if (off_diff <= 0)
|
|
/* no gap */
|
|
return;
|
|
if (m_bit_sz == 0 && off_diff < align * 8)
|
|
/* natural padding will take care of a gap */
|
|
return;
|
|
|
|
while (off_diff > 0) {
|
|
const char *pad_type;
|
|
int pad_bits;
|
|
|
|
if (ptr_bits > 32 && off_diff > 32) {
|
|
pad_type = "long";
|
|
pad_bits = chip_away_bits(off_diff, ptr_bits);
|
|
} else if (off_diff > 16) {
|
|
pad_type = "int";
|
|
pad_bits = chip_away_bits(off_diff, 32);
|
|
} else if (off_diff > 8) {
|
|
pad_type = "short";
|
|
pad_bits = chip_away_bits(off_diff, 16);
|
|
} else {
|
|
pad_type = "char";
|
|
pad_bits = chip_away_bits(off_diff, 8);
|
|
}
|
|
btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, pad_bits);
|
|
off_diff -= pad_bits;
|
|
}
|
|
}
|
|
|
|
static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t)
|
|
{
|
|
btf_dump_printf(d, "%s %s",
|
|
btf_is_struct(t) ? "struct" : "union",
|
|
btf_dump_type_name(d, id));
|
|
}
|
|
|
|
static void btf_dump_emit_struct_def(struct btf_dump *d,
|
|
__u32 id,
|
|
const struct btf_type *t,
|
|
int lvl)
|
|
{
|
|
const struct btf_member *m = btf_members(t);
|
|
bool is_struct = btf_is_struct(t);
|
|
int align, i, packed, off = 0;
|
|
__u16 vlen = btf_vlen(t);
|
|
|
|
packed = is_struct ? btf_is_struct_packed(d->btf, id, t) : 0;
|
|
|
|
btf_dump_printf(d, "%s%s%s {",
|
|
is_struct ? "struct" : "union",
|
|
t->name_off ? " " : "",
|
|
btf_dump_type_name(d, id));
|
|
|
|
for (i = 0; i < vlen; i++, m++) {
|
|
const char *fname;
|
|
int m_off, m_sz;
|
|
|
|
fname = btf_name_of(d, m->name_off);
|
|
m_sz = btf_member_bitfield_size(t, i);
|
|
m_off = btf_member_bit_offset(t, i);
|
|
align = packed ? 1 : btf__align_of(d->btf, m->type);
|
|
|
|
btf_dump_emit_bit_padding(d, off, m_off, m_sz, align, lvl + 1);
|
|
btf_dump_printf(d, "\n%s", pfx(lvl + 1));
|
|
btf_dump_emit_type_decl(d, m->type, fname, lvl + 1);
|
|
|
|
if (m_sz) {
|
|
btf_dump_printf(d, ": %d", m_sz);
|
|
off = m_off + m_sz;
|
|
} else {
|
|
m_sz = max(0, btf__resolve_size(d->btf, m->type));
|
|
off = m_off + m_sz * 8;
|
|
}
|
|
btf_dump_printf(d, ";");
|
|
}
|
|
|
|
/* pad at the end, if necessary */
|
|
if (is_struct) {
|
|
align = packed ? 1 : btf__align_of(d->btf, id);
|
|
btf_dump_emit_bit_padding(d, off, t->size * 8, 0, align,
|
|
lvl + 1);
|
|
}
|
|
|
|
if (vlen)
|
|
btf_dump_printf(d, "\n");
|
|
btf_dump_printf(d, "%s}", pfx(lvl));
|
|
if (packed)
|
|
btf_dump_printf(d, " __attribute__((packed))");
|
|
}
|
|
|
|
static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t)
|
|
{
|
|
btf_dump_printf(d, "enum %s", btf_dump_type_name(d, id));
|
|
}
|
|
|
|
static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t,
|
|
int lvl)
|
|
{
|
|
const struct btf_enum *v = btf_enum(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
const char *name;
|
|
size_t dup_cnt;
|
|
int i;
|
|
|
|
btf_dump_printf(d, "enum%s%s",
|
|
t->name_off ? " " : "",
|
|
btf_dump_type_name(d, id));
|
|
|
|
if (vlen) {
|
|
btf_dump_printf(d, " {");
|
|
for (i = 0; i < vlen; i++, v++) {
|
|
name = btf_name_of(d, v->name_off);
|
|
/* enumerators share namespace with typedef idents */
|
|
dup_cnt = btf_dump_name_dups(d, d->ident_names, name);
|
|
if (dup_cnt > 1) {
|
|
btf_dump_printf(d, "\n%s%s___%zu = %u,",
|
|
pfx(lvl + 1), name, dup_cnt,
|
|
(__u32)v->val);
|
|
} else {
|
|
btf_dump_printf(d, "\n%s%s = %u,",
|
|
pfx(lvl + 1), name,
|
|
(__u32)v->val);
|
|
}
|
|
}
|
|
btf_dump_printf(d, "\n%s}", pfx(lvl));
|
|
}
|
|
}
|
|
|
|
static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t)
|
|
{
|
|
const char *name = btf_dump_type_name(d, id);
|
|
|
|
if (btf_kflag(t))
|
|
btf_dump_printf(d, "union %s", name);
|
|
else
|
|
btf_dump_printf(d, "struct %s", name);
|
|
}
|
|
|
|
static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id,
|
|
const struct btf_type *t, int lvl)
|
|
{
|
|
const char *name = btf_dump_ident_name(d, id);
|
|
|
|
/*
|
|
* Old GCC versions are emitting invalid typedef for __gnuc_va_list
|
|
* pointing to VOID. This generates warnings from btf_dump() and
|
|
* results in uncompilable header file, so we are fixing it up here
|
|
* with valid typedef into __builtin_va_list.
|
|
*/
|
|
if (t->type == 0 && strcmp(name, "__gnuc_va_list") == 0) {
|
|
btf_dump_printf(d, "typedef __builtin_va_list __gnuc_va_list");
|
|
return;
|
|
}
|
|
|
|
btf_dump_printf(d, "typedef ");
|
|
btf_dump_emit_type_decl(d, t->type, name, lvl);
|
|
}
|
|
|
|
static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id)
|
|
{
|
|
__u32 *new_stack;
|
|
size_t new_cap;
|
|
|
|
if (d->decl_stack_cnt >= d->decl_stack_cap) {
|
|
new_cap = max(16, d->decl_stack_cap * 3 / 2);
|
|
new_stack = realloc(d->decl_stack,
|
|
new_cap * sizeof(new_stack[0]));
|
|
if (!new_stack)
|
|
return -ENOMEM;
|
|
d->decl_stack = new_stack;
|
|
d->decl_stack_cap = new_cap;
|
|
}
|
|
|
|
d->decl_stack[d->decl_stack_cnt++] = id;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Emit type declaration (e.g., field type declaration in a struct or argument
|
|
* declaration in function prototype) in correct C syntax.
|
|
*
|
|
* For most types it's trivial, but there are few quirky type declaration
|
|
* cases worth mentioning:
|
|
* - function prototypes (especially nesting of function prototypes);
|
|
* - arrays;
|
|
* - const/volatile/restrict for pointers vs other types.
|
|
*
|
|
* For a good discussion of *PARSING* C syntax (as a human), see
|
|
* Peter van der Linden's "Expert C Programming: Deep C Secrets",
|
|
* Ch.3 "Unscrambling Declarations in C".
|
|
*
|
|
* It won't help with BTF to C conversion much, though, as it's an opposite
|
|
* problem. So we came up with this algorithm in reverse to van der Linden's
|
|
* parsing algorithm. It goes from structured BTF representation of type
|
|
* declaration to a valid compilable C syntax.
|
|
*
|
|
* For instance, consider this C typedef:
|
|
* typedef const int * const * arr[10] arr_t;
|
|
* It will be represented in BTF with this chain of BTF types:
|
|
* [typedef] -> [array] -> [ptr] -> [const] -> [ptr] -> [const] -> [int]
|
|
*
|
|
* Notice how [const] modifier always goes before type it modifies in BTF type
|
|
* graph, but in C syntax, const/volatile/restrict modifiers are written to
|
|
* the right of pointers, but to the left of other types. There are also other
|
|
* quirks, like function pointers, arrays of them, functions returning other
|
|
* functions, etc.
|
|
*
|
|
* We handle that by pushing all the types to a stack, until we hit "terminal"
|
|
* type (int/enum/struct/union/fwd). Then depending on the kind of a type on
|
|
* top of a stack, modifiers are handled differently. Array/function pointers
|
|
* have also wildly different syntax and how nesting of them are done. See
|
|
* code for authoritative definition.
|
|
*
|
|
* To avoid allocating new stack for each independent chain of BTF types, we
|
|
* share one bigger stack, with each chain working only on its own local view
|
|
* of a stack frame. Some care is required to "pop" stack frames after
|
|
* processing type declaration chain.
|
|
*/
|
|
int btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
|
|
const struct btf_dump_emit_type_decl_opts *opts)
|
|
{
|
|
const char *fname;
|
|
int lvl;
|
|
|
|
if (!OPTS_VALID(opts, btf_dump_emit_type_decl_opts))
|
|
return -EINVAL;
|
|
|
|
fname = OPTS_GET(opts, field_name, "");
|
|
lvl = OPTS_GET(opts, indent_level, 0);
|
|
btf_dump_emit_type_decl(d, id, fname, lvl);
|
|
return 0;
|
|
}
|
|
|
|
static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
|
|
const char *fname, int lvl)
|
|
{
|
|
struct id_stack decl_stack;
|
|
const struct btf_type *t;
|
|
int err, stack_start;
|
|
|
|
stack_start = d->decl_stack_cnt;
|
|
for (;;) {
|
|
err = btf_dump_push_decl_stack_id(d, id);
|
|
if (err < 0) {
|
|
/*
|
|
* if we don't have enough memory for entire type decl
|
|
* chain, restore stack, emit warning, and try to
|
|
* proceed nevertheless
|
|
*/
|
|
pr_warn("not enough memory for decl stack:%d", err);
|
|
d->decl_stack_cnt = stack_start;
|
|
return;
|
|
}
|
|
|
|
/* VOID */
|
|
if (id == 0)
|
|
break;
|
|
|
|
t = btf__type_by_id(d->btf, id);
|
|
switch (btf_kind(t)) {
|
|
case BTF_KIND_PTR:
|
|
case BTF_KIND_VOLATILE:
|
|
case BTF_KIND_CONST:
|
|
case BTF_KIND_RESTRICT:
|
|
case BTF_KIND_FUNC_PROTO:
|
|
id = t->type;
|
|
break;
|
|
case BTF_KIND_ARRAY:
|
|
id = btf_array(t)->type;
|
|
break;
|
|
case BTF_KIND_INT:
|
|
case BTF_KIND_ENUM:
|
|
case BTF_KIND_FWD:
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION:
|
|
case BTF_KIND_TYPEDEF:
|
|
goto done;
|
|
default:
|
|
pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n",
|
|
btf_kind(t), id);
|
|
goto done;
|
|
}
|
|
}
|
|
done:
|
|
/*
|
|
* We might be inside a chain of declarations (e.g., array of function
|
|
* pointers returning anonymous (so inlined) structs, having another
|
|
* array field). Each of those needs its own "stack frame" to handle
|
|
* emitting of declarations. Those stack frames are non-overlapping
|
|
* portions of shared btf_dump->decl_stack. To make it a bit nicer to
|
|
* handle this set of nested stacks, we create a view corresponding to
|
|
* our own "stack frame" and work with it as an independent stack.
|
|
* We'll need to clean up after emit_type_chain() returns, though.
|
|
*/
|
|
decl_stack.ids = d->decl_stack + stack_start;
|
|
decl_stack.cnt = d->decl_stack_cnt - stack_start;
|
|
btf_dump_emit_type_chain(d, &decl_stack, fname, lvl);
|
|
/*
|
|
* emit_type_chain() guarantees that it will pop its entire decl_stack
|
|
* frame before returning. But it works with a read-only view into
|
|
* decl_stack, so it doesn't actually pop anything from the
|
|
* perspective of shared btf_dump->decl_stack, per se. We need to
|
|
* reset decl_stack state to how it was before us to avoid it growing
|
|
* all the time.
|
|
*/
|
|
d->decl_stack_cnt = stack_start;
|
|
}
|
|
|
|
static void btf_dump_emit_mods(struct btf_dump *d, struct id_stack *decl_stack)
|
|
{
|
|
const struct btf_type *t;
|
|
__u32 id;
|
|
|
|
while (decl_stack->cnt) {
|
|
id = decl_stack->ids[decl_stack->cnt - 1];
|
|
t = btf__type_by_id(d->btf, id);
|
|
|
|
switch (btf_kind(t)) {
|
|
case BTF_KIND_VOLATILE:
|
|
btf_dump_printf(d, "volatile ");
|
|
break;
|
|
case BTF_KIND_CONST:
|
|
btf_dump_printf(d, "const ");
|
|
break;
|
|
case BTF_KIND_RESTRICT:
|
|
btf_dump_printf(d, "restrict ");
|
|
break;
|
|
default:
|
|
return;
|
|
}
|
|
decl_stack->cnt--;
|
|
}
|
|
}
|
|
|
|
static void btf_dump_drop_mods(struct btf_dump *d, struct id_stack *decl_stack)
|
|
{
|
|
const struct btf_type *t;
|
|
__u32 id;
|
|
|
|
while (decl_stack->cnt) {
|
|
id = decl_stack->ids[decl_stack->cnt - 1];
|
|
t = btf__type_by_id(d->btf, id);
|
|
if (!btf_is_mod(t))
|
|
return;
|
|
decl_stack->cnt--;
|
|
}
|
|
}
|
|
|
|
static void btf_dump_emit_name(const struct btf_dump *d,
|
|
const char *name, bool last_was_ptr)
|
|
{
|
|
bool separate = name[0] && !last_was_ptr;
|
|
|
|
btf_dump_printf(d, "%s%s", separate ? " " : "", name);
|
|
}
|
|
|
|
static void btf_dump_emit_type_chain(struct btf_dump *d,
|
|
struct id_stack *decls,
|
|
const char *fname, int lvl)
|
|
{
|
|
/*
|
|
* last_was_ptr is used to determine if we need to separate pointer
|
|
* asterisk (*) from previous part of type signature with space, so
|
|
* that we get `int ***`, instead of `int * * *`. We default to true
|
|
* for cases where we have single pointer in a chain. E.g., in ptr ->
|
|
* func_proto case. func_proto will start a new emit_type_chain call
|
|
* with just ptr, which should be emitted as (*) or (*<fname>), so we
|
|
* don't want to prepend space for that last pointer.
|
|
*/
|
|
bool last_was_ptr = true;
|
|
const struct btf_type *t;
|
|
const char *name;
|
|
__u16 kind;
|
|
__u32 id;
|
|
|
|
while (decls->cnt) {
|
|
id = decls->ids[--decls->cnt];
|
|
if (id == 0) {
|
|
/* VOID is a special snowflake */
|
|
btf_dump_emit_mods(d, decls);
|
|
btf_dump_printf(d, "void");
|
|
last_was_ptr = false;
|
|
continue;
|
|
}
|
|
|
|
t = btf__type_by_id(d->btf, id);
|
|
kind = btf_kind(t);
|
|
|
|
switch (kind) {
|
|
case BTF_KIND_INT:
|
|
btf_dump_emit_mods(d, decls);
|
|
name = btf_name_of(d, t->name_off);
|
|
btf_dump_printf(d, "%s", name);
|
|
break;
|
|
case BTF_KIND_STRUCT:
|
|
case BTF_KIND_UNION:
|
|
btf_dump_emit_mods(d, decls);
|
|
/* inline anonymous struct/union */
|
|
if (t->name_off == 0)
|
|
btf_dump_emit_struct_def(d, id, t, lvl);
|
|
else
|
|
btf_dump_emit_struct_fwd(d, id, t);
|
|
break;
|
|
case BTF_KIND_ENUM:
|
|
btf_dump_emit_mods(d, decls);
|
|
/* inline anonymous enum */
|
|
if (t->name_off == 0)
|
|
btf_dump_emit_enum_def(d, id, t, lvl);
|
|
else
|
|
btf_dump_emit_enum_fwd(d, id, t);
|
|
break;
|
|
case BTF_KIND_FWD:
|
|
btf_dump_emit_mods(d, decls);
|
|
btf_dump_emit_fwd_def(d, id, t);
|
|
break;
|
|
case BTF_KIND_TYPEDEF:
|
|
btf_dump_emit_mods(d, decls);
|
|
btf_dump_printf(d, "%s", btf_dump_ident_name(d, id));
|
|
break;
|
|
case BTF_KIND_PTR:
|
|
btf_dump_printf(d, "%s", last_was_ptr ? "*" : " *");
|
|
break;
|
|
case BTF_KIND_VOLATILE:
|
|
btf_dump_printf(d, " volatile");
|
|
break;
|
|
case BTF_KIND_CONST:
|
|
btf_dump_printf(d, " const");
|
|
break;
|
|
case BTF_KIND_RESTRICT:
|
|
btf_dump_printf(d, " restrict");
|
|
break;
|
|
case BTF_KIND_ARRAY: {
|
|
const struct btf_array *a = btf_array(t);
|
|
const struct btf_type *next_t;
|
|
__u32 next_id;
|
|
bool multidim;
|
|
/*
|
|
* GCC has a bug
|
|
* (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=8354)
|
|
* which causes it to emit extra const/volatile
|
|
* modifiers for an array, if array's element type has
|
|
* const/volatile modifiers. Clang doesn't do that.
|
|
* In general, it doesn't seem very meaningful to have
|
|
* a const/volatile modifier for array, so we are
|
|
* going to silently skip them here.
|
|
*/
|
|
btf_dump_drop_mods(d, decls);
|
|
|
|
if (decls->cnt == 0) {
|
|
btf_dump_emit_name(d, fname, last_was_ptr);
|
|
btf_dump_printf(d, "[%u]", a->nelems);
|
|
return;
|
|
}
|
|
|
|
next_id = decls->ids[decls->cnt - 1];
|
|
next_t = btf__type_by_id(d->btf, next_id);
|
|
multidim = btf_is_array(next_t);
|
|
/* we need space if we have named non-pointer */
|
|
if (fname[0] && !last_was_ptr)
|
|
btf_dump_printf(d, " ");
|
|
/* no parentheses for multi-dimensional array */
|
|
if (!multidim)
|
|
btf_dump_printf(d, "(");
|
|
btf_dump_emit_type_chain(d, decls, fname, lvl);
|
|
if (!multidim)
|
|
btf_dump_printf(d, ")");
|
|
btf_dump_printf(d, "[%u]", a->nelems);
|
|
return;
|
|
}
|
|
case BTF_KIND_FUNC_PROTO: {
|
|
const struct btf_param *p = btf_params(t);
|
|
__u16 vlen = btf_vlen(t);
|
|
int i;
|
|
|
|
/*
|
|
* GCC emits extra volatile qualifier for
|
|
* __attribute__((noreturn)) function pointers. Clang
|
|
* doesn't do it. It's a GCC quirk for backwards
|
|
* compatibility with code written for GCC <2.5. So,
|
|
* similarly to extra qualifiers for array, just drop
|
|
* them, instead of handling them.
|
|
*/
|
|
btf_dump_drop_mods(d, decls);
|
|
if (decls->cnt) {
|
|
btf_dump_printf(d, " (");
|
|
btf_dump_emit_type_chain(d, decls, fname, lvl);
|
|
btf_dump_printf(d, ")");
|
|
} else {
|
|
btf_dump_emit_name(d, fname, last_was_ptr);
|
|
}
|
|
btf_dump_printf(d, "(");
|
|
/*
|
|
* Clang for BPF target generates func_proto with no
|
|
* args as a func_proto with a single void arg (e.g.,
|
|
* `int (*f)(void)` vs just `int (*f)()`). We are
|
|
* going to pretend there are no args for such case.
|
|
*/
|
|
if (vlen == 1 && p->type == 0) {
|
|
btf_dump_printf(d, ")");
|
|
return;
|
|
}
|
|
|
|
for (i = 0; i < vlen; i++, p++) {
|
|
if (i > 0)
|
|
btf_dump_printf(d, ", ");
|
|
|
|
/* last arg of type void is vararg */
|
|
if (i == vlen - 1 && p->type == 0) {
|
|
btf_dump_printf(d, "...");
|
|
break;
|
|
}
|
|
|
|
name = btf_name_of(d, p->name_off);
|
|
btf_dump_emit_type_decl(d, p->type, name, lvl);
|
|
}
|
|
|
|
btf_dump_printf(d, ")");
|
|
return;
|
|
}
|
|
default:
|
|
pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n",
|
|
kind, id);
|
|
return;
|
|
}
|
|
|
|
last_was_ptr = kind == BTF_KIND_PTR;
|
|
}
|
|
|
|
btf_dump_emit_name(d, fname, last_was_ptr);
|
|
}
|
|
|
|
/* return number of duplicates (occurrences) of a given name */
|
|
static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
|
|
const char *orig_name)
|
|
{
|
|
size_t dup_cnt = 0;
|
|
|
|
hashmap__find(name_map, orig_name, (void **)&dup_cnt);
|
|
dup_cnt++;
|
|
hashmap__set(name_map, orig_name, (void *)dup_cnt, NULL, NULL);
|
|
|
|
return dup_cnt;
|
|
}
|
|
|
|
static const char *btf_dump_resolve_name(struct btf_dump *d, __u32 id,
|
|
struct hashmap *name_map)
|
|
{
|
|
struct btf_dump_type_aux_state *s = &d->type_states[id];
|
|
const struct btf_type *t = btf__type_by_id(d->btf, id);
|
|
const char *orig_name = btf_name_of(d, t->name_off);
|
|
const char **cached_name = &d->cached_names[id];
|
|
size_t dup_cnt;
|
|
|
|
if (t->name_off == 0)
|
|
return "";
|
|
|
|
if (s->name_resolved)
|
|
return *cached_name ? *cached_name : orig_name;
|
|
|
|
dup_cnt = btf_dump_name_dups(d, name_map, orig_name);
|
|
if (dup_cnt > 1) {
|
|
const size_t max_len = 256;
|
|
char new_name[max_len];
|
|
|
|
snprintf(new_name, max_len, "%s___%zu", orig_name, dup_cnt);
|
|
*cached_name = strdup(new_name);
|
|
}
|
|
|
|
s->name_resolved = 1;
|
|
return *cached_name ? *cached_name : orig_name;
|
|
}
|
|
|
|
static const char *btf_dump_type_name(struct btf_dump *d, __u32 id)
|
|
{
|
|
return btf_dump_resolve_name(d, id, d->type_names);
|
|
}
|
|
|
|
static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id)
|
|
{
|
|
return btf_dump_resolve_name(d, id, d->ident_names);
|
|
}
|