| // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) |
| |
| /* |
| * BTF-to-C type converter. |
| * |
| * Copyright (c) 2019 Facebook |
| */ |
| |
| #include <stdbool.h> |
| #include <stddef.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <errno.h> |
| #include <linux/err.h> |
| #include <linux/btf.h> |
| #include "btf.h" |
| #include "hashmap.h" |
| #include "libbpf.h" |
| #include "libbpf_internal.h" |
| |
| static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t"; |
| static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1; |
| |
| static const char *pfx(int lvl) |
| { |
| return lvl >= PREFIX_CNT ? PREFIXES : &PREFIXES[PREFIX_CNT - lvl]; |
| } |
| |
| enum btf_dump_type_order_state { |
| NOT_ORDERED, |
| ORDERING, |
| ORDERED, |
| }; |
| |
| enum btf_dump_type_emit_state { |
| NOT_EMITTED, |
| EMITTING, |
| EMITTED, |
| }; |
| |
| /* per-type auxiliary state */ |
| struct btf_dump_type_aux_state { |
| /* topological sorting state */ |
| enum btf_dump_type_order_state order_state: 2; |
| /* emitting state used to determine the need for forward declaration */ |
| enum btf_dump_type_emit_state emit_state: 2; |
| /* whether forward declaration was already emitted */ |
| __u8 fwd_emitted: 1; |
| /* whether unique non-duplicate name was already assigned */ |
| __u8 name_resolved: 1; |
| /* whether type is referenced from any other type */ |
| __u8 referenced: 1; |
| }; |
| |
| struct btf_dump { |
| const struct btf *btf; |
| const struct btf_ext *btf_ext; |
| btf_dump_printf_fn_t printf_fn; |
| struct btf_dump_opts opts; |
| |
| /* per-type auxiliary state */ |
| struct btf_dump_type_aux_state *type_states; |
| /* per-type optional cached unique name, must be freed, if present */ |
| const char **cached_names; |
| |
| /* topo-sorted list of dependent type definitions */ |
| __u32 *emit_queue; |
| int emit_queue_cap; |
| int emit_queue_cnt; |
| |
| /* |
| * stack of type declarations (e.g., chain of modifiers, arrays, |
| * funcs, etc) |
| */ |
| __u32 *decl_stack; |
| int decl_stack_cap; |
| int decl_stack_cnt; |
| |
| /* maps struct/union/enum name to a number of name occurrences */ |
| struct hashmap *type_names; |
| /* |
| * maps typedef identifiers and enum value names to a number of such |
| * name occurrences |
| */ |
| struct hashmap *ident_names; |
| }; |
| |
| static size_t str_hash_fn(const void *key, void *ctx) |
| { |
| const char *s = key; |
| size_t h = 0; |
| |
| while (*s) { |
| h = h * 31 + *s; |
| s++; |
| } |
| return h; |
| } |
| |
| static bool str_equal_fn(const void *a, const void *b, void *ctx) |
| { |
| return strcmp(a, b) == 0; |
| } |
| |
| static const char *btf_name_of(const struct btf_dump *d, __u32 name_off) |
| { |
| return btf__name_by_offset(d->btf, name_off); |
| } |
| |
| static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...) |
| { |
| va_list args; |
| |
| va_start(args, fmt); |
| d->printf_fn(d->opts.ctx, fmt, args); |
| va_end(args); |
| } |
| |
| struct btf_dump *btf_dump__new(const struct btf *btf, |
| const struct btf_ext *btf_ext, |
| const struct btf_dump_opts *opts, |
| btf_dump_printf_fn_t printf_fn) |
| { |
| struct btf_dump *d; |
| int err; |
| |
| d = calloc(1, sizeof(struct btf_dump)); |
| if (!d) |
| return ERR_PTR(-ENOMEM); |
| |
| d->btf = btf; |
| d->btf_ext = btf_ext; |
| d->printf_fn = printf_fn; |
| d->opts.ctx = opts ? opts->ctx : NULL; |
| |
| d->type_names = hashmap__new(str_hash_fn, str_equal_fn, NULL); |
| if (IS_ERR(d->type_names)) { |
| err = PTR_ERR(d->type_names); |
| d->type_names = NULL; |
| btf_dump__free(d); |
| return ERR_PTR(err); |
| } |
| d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL); |
| if (IS_ERR(d->ident_names)) { |
| err = PTR_ERR(d->ident_names); |
| d->ident_names = NULL; |
| btf_dump__free(d); |
| return ERR_PTR(err); |
| } |
| |
| return d; |
| } |
| |
| void btf_dump__free(struct btf_dump *d) |
| { |
| int i, cnt; |
| |
| if (!d) |
| return; |
| |
| free(d->type_states); |
| if (d->cached_names) { |
| /* any set cached name is owned by us and should be freed */ |
| for (i = 0, cnt = btf__get_nr_types(d->btf); i <= cnt; i++) { |
| if (d->cached_names[i]) |
| free((void *)d->cached_names[i]); |
| } |
| } |
| free(d->cached_names); |
| free(d->emit_queue); |
| free(d->decl_stack); |
| hashmap__free(d->type_names); |
| hashmap__free(d->ident_names); |
| |
| free(d); |
| } |
| |
| static int btf_dump_mark_referenced(struct btf_dump *d); |
| static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr); |
| static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id); |
| |
| /* |
| * Dump BTF type in a compilable C syntax, including all the necessary |
| * dependent types, necessary for compilation. If some of the dependent types |
| * were already emitted as part of previous btf_dump__dump_type() invocation |
| * for another type, they won't be emitted again. This API allows callers to |
| * filter out BTF types according to user-defined criterias and emitted only |
| * minimal subset of types, necessary to compile everything. Full struct/union |
| * definitions will still be emitted, even if the only usage is through |
| * pointer and could be satisfied with just a forward declaration. |
| * |
| * Dumping is done in two high-level passes: |
| * 1. Topologically sort type definitions to satisfy C rules of compilation. |
| * 2. Emit type definitions in C syntax. |
| * |
| * Returns 0 on success; <0, otherwise. |
| */ |
| int btf_dump__dump_type(struct btf_dump *d, __u32 id) |
| { |
| int err, i; |
| |
| if (id > btf__get_nr_types(d->btf)) |
| return -EINVAL; |
| |
| /* type states are lazily allocated, as they might not be needed */ |
| if (!d->type_states) { |
| d->type_states = calloc(1 + btf__get_nr_types(d->btf), |
| sizeof(d->type_states[0])); |
| if (!d->type_states) |
| return -ENOMEM; |
| d->cached_names = calloc(1 + btf__get_nr_types(d->btf), |
| sizeof(d->cached_names[0])); |
| if (!d->cached_names) |
| return -ENOMEM; |
| |
| /* VOID is special */ |
| d->type_states[0].order_state = ORDERED; |
| d->type_states[0].emit_state = EMITTED; |
| |
| /* eagerly determine referenced types for anon enums */ |
| err = btf_dump_mark_referenced(d); |
| if (err) |
| return err; |
| } |
| |
| d->emit_queue_cnt = 0; |
| err = btf_dump_order_type(d, id, false); |
| if (err < 0) |
| return err; |
| |
| for (i = 0; i < d->emit_queue_cnt; i++) |
| btf_dump_emit_type(d, d->emit_queue[i], 0 /*top-level*/); |
| |
| return 0; |
| } |
| |
| /* |
| * Mark all types that are referenced from any other type. This is used to |
| * determine top-level anonymous enums that need to be emitted as an |
| * independent type declarations. |
| * Anonymous enums come in two flavors: either embedded in a struct's field |
| * definition, in which case they have to be declared inline as part of field |
| * type declaration; or as a top-level anonymous enum, typically used for |
| * declaring global constants. It's impossible to distinguish between two |
| * without knowning whether given enum type was referenced from other type: |
| * top-level anonymous enum won't be referenced by anything, while embedded |
| * one will. |
| */ |
| static int btf_dump_mark_referenced(struct btf_dump *d) |
| { |
| int i, j, n = btf__get_nr_types(d->btf); |
| const struct btf_type *t; |
| __u16 vlen; |
| |
| for (i = 1; i <= n; i++) { |
| t = btf__type_by_id(d->btf, i); |
| vlen = btf_vlen(t); |
| |
| switch (btf_kind(t)) { |
| case BTF_KIND_INT: |
| case BTF_KIND_ENUM: |
| case BTF_KIND_FWD: |
| break; |
| |
| case BTF_KIND_VOLATILE: |
| case BTF_KIND_CONST: |
| case BTF_KIND_RESTRICT: |
| case BTF_KIND_PTR: |
| case BTF_KIND_TYPEDEF: |
| case BTF_KIND_FUNC: |
| case BTF_KIND_VAR: |
| d->type_states[t->type].referenced = 1; |
| break; |
| |
| case BTF_KIND_ARRAY: { |
| const struct btf_array *a = btf_array(t); |
| |
| d->type_states[a->index_type].referenced = 1; |
| d->type_states[a->type].referenced = 1; |
| break; |
| } |
| case BTF_KIND_STRUCT: |
| case BTF_KIND_UNION: { |
| const struct btf_member *m = btf_members(t); |
| |
| for (j = 0; j < vlen; j++, m++) |
| d->type_states[m->type].referenced = 1; |
| break; |
| } |
| case BTF_KIND_FUNC_PROTO: { |
| const struct btf_param *p = btf_params(t); |
| |
| for (j = 0; j < vlen; j++, p++) |
| d->type_states[p->type].referenced = 1; |
| break; |
| } |
| case BTF_KIND_DATASEC: { |
| const struct btf_var_secinfo *v = btf_var_secinfos(t); |
| |
| for (j = 0; j < vlen; j++, v++) |
| d->type_states[v->type].referenced = 1; |
| break; |
| } |
| default: |
| return -EINVAL; |
| } |
| } |
| return 0; |
| } |
| static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id) |
| { |
| __u32 *new_queue; |
| size_t new_cap; |
| |
| if (d->emit_queue_cnt >= d->emit_queue_cap) { |
| new_cap = max(16, d->emit_queue_cap * 3 / 2); |
| new_queue = realloc(d->emit_queue, |
| new_cap * sizeof(new_queue[0])); |
| if (!new_queue) |
| return -ENOMEM; |
| d->emit_queue = new_queue; |
| d->emit_queue_cap = new_cap; |
| } |
| |
| d->emit_queue[d->emit_queue_cnt++] = id; |
| return 0; |
| } |
| |
| /* |
| * Determine order of emitting dependent types and specified type to satisfy |
| * C compilation rules. This is done through topological sorting with an |
| * additional complication which comes from C rules. The main idea for C is |
| * that if some type is "embedded" into a struct/union, it's size needs to be |
| * known at the time of definition of containing type. E.g., for: |
| * |
| * struct A {}; |
| * struct B { struct A x; } |
| * |
| * struct A *HAS* to be defined before struct B, because it's "embedded", |
| * i.e., it is part of struct B layout. But in the following case: |
| * |
| * struct A; |
| * struct B { struct A *x; } |
| * struct A {}; |
| * |
| * it's enough to just have a forward declaration of struct A at the time of |
| * struct B definition, as struct B has a pointer to struct A, so the size of |
| * field x is known without knowing struct A size: it's sizeof(void *). |
| * |
| * Unfortunately, there are some trickier cases we need to handle, e.g.: |
| * |
| * struct A {}; // if this was forward-declaration: compilation error |
| * struct B { |
| * struct { // anonymous struct |
| * struct A y; |
| * } *x; |
| * }; |
| * |
| * In this case, struct B's field x is a pointer, so it's size is known |
| * regardless of the size of (anonymous) struct it points to. But because this |
| * struct is anonymous and thus defined inline inside struct B, *and* it |
| * embeds struct A, compiler requires full definition of struct A to be known |
| * before struct B can be defined. This creates a transitive dependency |
| * between struct A and struct B. If struct A was forward-declared before |
| * struct B definition and fully defined after struct B definition, that would |
| * trigger compilation error. |
| * |
| * All this means that while we are doing topological sorting on BTF type |
| * graph, we need to determine relationships between different types (graph |
| * nodes): |
| * - weak link (relationship) between X and Y, if Y *CAN* be |
| * forward-declared at the point of X definition; |
| * - strong link, if Y *HAS* to be fully-defined before X can be defined. |
| * |
| * The rule is as follows. Given a chain of BTF types from X to Y, if there is |
| * BTF_KIND_PTR type in the chain and at least one non-anonymous type |
| * Z (excluding X, including Y), then link is weak. Otherwise, it's strong. |
| * Weak/strong relationship is determined recursively during DFS traversal and |
| * is returned as a result from btf_dump_order_type(). |
| * |
| * btf_dump_order_type() is trying to avoid unnecessary forward declarations, |
| * but it is not guaranteeing that no extraneous forward declarations will be |
| * emitted. |
| * |
| * To avoid extra work, algorithm marks some of BTF types as ORDERED, when |
| * it's done with them, but not for all (e.g., VOLATILE, CONST, RESTRICT, |
| * ARRAY, FUNC_PROTO), as weak/strong semantics for those depends on the |
| * entire graph path, so depending where from one came to that BTF type, it |
| * might cause weak or strong ordering. For types like STRUCT/UNION/INT/ENUM, |
| * once they are processed, there is no need to do it again, so they are |
| * marked as ORDERED. We can mark PTR as ORDERED as well, as it semi-forces |
| * weak link, unless subsequent referenced STRUCT/UNION/ENUM is anonymous. But |
| * in any case, once those are processed, no need to do it again, as the |
| * result won't change. |
| * |
| * Returns: |
| * - 1, if type is part of strong link (so there is strong topological |
| * ordering requirements); |
| * - 0, if type is part of weak link (so can be satisfied through forward |
| * declaration); |
| * - <0, on error (e.g., unsatisfiable type loop detected). |
| */ |
| static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr) |
| { |
| /* |
| * Order state is used to detect strong link cycles, but only for BTF |
| * kinds that are or could be an independent definition (i.e., |
| * stand-alone fwd decl, enum, typedef, struct, union). Ptrs, arrays, |
| * func_protos, modifiers are just means to get to these definitions. |
| * Int/void don't need definitions, they are assumed to be always |
| * properly defined. We also ignore datasec, var, and funcs for now. |
| * So for all non-defining kinds, we never even set ordering state, |
| * for defining kinds we set ORDERING and subsequently ORDERED if it |
| * forms a strong link. |
| */ |
| struct btf_dump_type_aux_state *tstate = &d->type_states[id]; |
| const struct btf_type *t; |
| __u16 vlen; |
| int err, i; |
| |
| /* return true, letting typedefs know that it's ok to be emitted */ |
| if (tstate->order_state == ORDERED) |
| return 1; |
| |
| t = btf__type_by_id(d->btf, id); |
| |
| if (tstate->order_state == ORDERING) { |
| /* type loop, but resolvable through fwd declaration */ |
| if (btf_is_composite(t) && through_ptr && t->name_off != 0) |
| return 0; |
| pr_warning("unsatisfiable type cycle, id:[%u]\n", id); |
| return -ELOOP; |
| } |
| |
| switch (btf_kind(t)) { |
| case BTF_KIND_INT: |
| tstate->order_state = ORDERED; |
| return 0; |
| |
| case BTF_KIND_PTR: |
| err = btf_dump_order_type(d, t->type, true); |
| tstate->order_state = ORDERED; |
| return err; |
| |
| case BTF_KIND_ARRAY: |
| return btf_dump_order_type(d, btf_array(t)->type, false); |
| |
| case BTF_KIND_STRUCT: |
| case BTF_KIND_UNION: { |
| const struct btf_member *m = btf_members(t); |
| /* |
| * struct/union is part of strong link, only if it's embedded |
| * (so no ptr in a path) or it's anonymous (so has to be |
| * defined inline, even if declared through ptr) |
| */ |
| if (through_ptr && t->name_off != 0) |
| return 0; |
| |
| tstate->order_state = ORDERING; |
| |
| 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_warning("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 int btf_align_of(const struct btf *btf, __u32 id) |
| { |
| const struct btf_type *t = btf__type_by_id(btf, id); |
| __u16 kind = btf_kind(t); |
| |
| switch (kind) { |
| case BTF_KIND_INT: |
| case BTF_KIND_ENUM: |
| return min(sizeof(void *), t->size); |
| case BTF_KIND_PTR: |
| return sizeof(void *); |
| case BTF_KIND_TYPEDEF: |
| case BTF_KIND_VOLATILE: |
| case BTF_KIND_CONST: |
| case BTF_KIND_RESTRICT: |
| return btf_align_of(btf, t->type); |
| case BTF_KIND_ARRAY: |
| return btf_align_of(btf, btf_array(t)->type); |
| case BTF_KIND_STRUCT: |
| case BTF_KIND_UNION: { |
| const struct btf_member *m = btf_members(t); |
| __u16 vlen = btf_vlen(t); |
| int i, align = 1; |
| |
| for (i = 0; i < vlen; i++, m++) |
| align = max(align, btf_align_of(btf, m->type)); |
| |
| return align; |
| } |
| default: |
| pr_warning("unsupported BTF_KIND:%u\n", btf_kind(t)); |
| return 1; |
| } |
| } |
| |
| 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 (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 (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 = %d,", |
| pfx(lvl + 1), name, dup_cnt, |
| (__s32)v->val); |
| } else { |
| btf_dump_printf(d, "\n%s%s = %d,", |
| pfx(lvl + 1), name, |
| (__s32)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); |
| |
| 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. |
| */ |
| 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_warning("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_warning("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_warning("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); |
| } |