btf_encoder: Reduce the size of encode_cu() by moving var encoding to separate method
Just to make code more manageable, no change intended. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo
parent
f62196d3be
commit
d348b37ed1
233
btf_encoder.c
233
btf_encoder.c
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@ -1140,6 +1140,125 @@ static bool has_arg_names(struct cu *cu, struct ftype *ftype)
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return true;
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}
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static int btf_encoder__encode_cu_variables(struct btf_encoder *encoder, struct cu *cu, uint32_t type_id_off)
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{
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uint32_t core_id;
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struct tag *pos;
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int err = -1;
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if (encoder->percpu.shndx == 0 || !encoder->symtab)
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return 0;
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if (encoder->verbose)
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printf("search cu '%s' for percpu global variables.\n", cu->name);
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cu__for_each_variable(cu, core_id, pos) {
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struct variable *var = tag__variable(pos);
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uint32_t size, type, linkage;
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const char *name, *dwarf_name;
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const struct tag *tag;
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uint64_t addr;
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int id;
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if (var->declaration && !var->spec)
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continue;
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/* percpu variables are allocated in global space */
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if (variable__scope(var) != VSCOPE_GLOBAL && !var->spec)
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continue;
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/* addr has to be recorded before we follow spec */
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addr = var->ip.addr;
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dwarf_name = variable__name(var, cu);
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/* DWARF takes into account .data..percpu section offset
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* within its segment, which for vmlinux is 0, but for kernel
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* modules is >0. ELF symbols, on the other hand, don't take
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* into account these offsets (as they are relative to the
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* section start), so to match DWARF and ELF symbols we need
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* to negate the section base address here.
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*/
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if (addr < encoder->percpu.base_addr || addr >= encoder->percpu.base_addr + encoder->percpu.sec_sz)
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continue;
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addr -= encoder->percpu.base_addr;
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if (!btf_encoder__percpu_var_exists(encoder, addr, &size, &name))
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continue; /* not a per-CPU variable */
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/* A lot of "special" DWARF variables (e.g, __UNIQUE_ID___xxx)
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* have addr == 0, which is the same as, say, valid
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* fixed_percpu_data per-CPU variable. To distinguish between
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* them, additionally compare DWARF and ELF symbol names. If
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* DWARF doesn't provide proper name, pessimistically assume
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* bad variable.
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*
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* Examples of such special variables are:
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*
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* 1. __ADDRESSABLE(sym), which are forcely emitted as symbols.
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* 2. __UNIQUE_ID(prefix), which are introduced to generate unique ids.
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* 3. __exitcall(fn), functions which are labeled as exit calls.
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*
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* This is relevant only for vmlinux image, as for kernel
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* modules per-CPU data section has non-zero offset so all
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* per-CPU symbols have non-zero values.
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*/
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if (var->ip.addr == 0) {
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if (!dwarf_name || strcmp(dwarf_name, name))
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continue;
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}
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if (var->spec)
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var = var->spec;
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if (var->ip.tag.type == 0) {
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fprintf(stderr, "error: found variable '%s' in CU '%s' that has void type\n",
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name, cu->name);
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if (encoder->force)
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continue;
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err = -1;
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break;
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}
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tag = cu__type(cu, var->ip.tag.type);
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if (tag__size(tag, cu) == 0) {
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if (encoder->verbose)
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fprintf(stderr, "Ignoring zero-sized per-CPU variable '%s'...\n", dwarf_name ?: "<missing name>");
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continue;
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}
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type = var->ip.tag.type + type_id_off;
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linkage = var->external ? BTF_VAR_GLOBAL_ALLOCATED : BTF_VAR_STATIC;
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if (encoder->verbose) {
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printf("Variable '%s' from CU '%s' at address 0x%" PRIx64 " encoded\n",
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name, cu->name, addr);
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}
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/* add a BTF_KIND_VAR in encoder->types */
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id = btf_encoder__add_var(encoder, type, name, linkage);
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if (id < 0) {
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fprintf(stderr, "error: failed to encode variable '%s' at addr 0x%" PRIx64 "\n",
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name, addr);
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goto out;
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}
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/*
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* add a BTF_VAR_SECINFO in encoder->percpu_secinfo, which will be added into
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* encoder->types later when we add BTF_VAR_DATASEC.
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*/
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id = btf_encoder__add_var_secinfo(encoder, id, addr, size);
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if (id < 0) {
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fprintf(stderr, "error: failed to encode section info for variable '%s' at addr 0x%" PRIx64 "\n",
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name, addr);
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goto out;
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}
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}
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err = 0;
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out:
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return err;
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}
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struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filename, struct btf *base_btf, bool skip_encoding_vars, bool force, bool gen_floats, bool verbose)
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{
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struct btf_encoder *encoder = zalloc(sizeof(*encoder));
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@ -1237,7 +1356,6 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu)
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{
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uint32_t type_id_off = btf__get_nr_types(encoder->btf);
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uint32_t core_id;
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struct variable *var;
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struct function *fn;
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struct tag *pos;
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int err = 0;
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@ -1316,117 +1434,8 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu)
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}
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}
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if (encoder->skip_encoding_vars)
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goto out;
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if (encoder->percpu.shndx == 0 || !encoder->symtab)
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goto out;
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if (encoder->verbose)
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printf("search cu '%s' for percpu global variables.\n", cu->name);
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cu__for_each_variable(cu, core_id, pos) {
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uint32_t size, type, linkage;
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const char *name, *dwarf_name;
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const struct tag *tag;
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uint64_t addr;
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int id;
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var = tag__variable(pos);
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if (var->declaration && !var->spec)
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continue;
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/* percpu variables are allocated in global space */
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if (variable__scope(var) != VSCOPE_GLOBAL && !var->spec)
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continue;
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/* addr has to be recorded before we follow spec */
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addr = var->ip.addr;
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dwarf_name = variable__name(var, cu);
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/* DWARF takes into account .data..percpu section offset
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* within its segment, which for vmlinux is 0, but for kernel
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* modules is >0. ELF symbols, on the other hand, don't take
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* into account these offsets (as they are relative to the
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* section start), so to match DWARF and ELF symbols we need
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* to negate the section base address here.
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*/
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if (addr < encoder->percpu.base_addr || addr >= encoder->percpu.base_addr + encoder->percpu.sec_sz)
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continue;
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addr -= encoder->percpu.base_addr;
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if (!btf_encoder__percpu_var_exists(encoder, addr, &size, &name))
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continue; /* not a per-CPU variable */
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/* A lot of "special" DWARF variables (e.g, __UNIQUE_ID___xxx)
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* have addr == 0, which is the same as, say, valid
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* fixed_percpu_data per-CPU variable. To distinguish between
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* them, additionally compare DWARF and ELF symbol names. If
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* DWARF doesn't provide proper name, pessimistically assume
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* bad variable.
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*
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* Examples of such special variables are:
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*
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* 1. __ADDRESSABLE(sym), which are forcely emitted as symbols.
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* 2. __UNIQUE_ID(prefix), which are introduced to generate unique ids.
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* 3. __exitcall(fn), functions which are labeled as exit calls.
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*
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* This is relevant only for vmlinux image, as for kernel
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* modules per-CPU data section has non-zero offset so all
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* per-CPU symbols have non-zero values.
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*/
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if (var->ip.addr == 0) {
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if (!dwarf_name || strcmp(dwarf_name, name))
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continue;
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}
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if (var->spec)
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var = var->spec;
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if (var->ip.tag.type == 0) {
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fprintf(stderr, "error: found variable '%s' in CU '%s' that has void type\n",
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name, cu->name);
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if (encoder->force)
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continue;
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err = -1;
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break;
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}
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tag = cu__type(cu, var->ip.tag.type);
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if (tag__size(tag, cu) == 0) {
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if (encoder->verbose)
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fprintf(stderr, "Ignoring zero-sized per-CPU variable '%s'...\n", dwarf_name ?: "<missing name>");
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continue;
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}
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type = var->ip.tag.type + type_id_off;
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linkage = var->external ? BTF_VAR_GLOBAL_ALLOCATED : BTF_VAR_STATIC;
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if (encoder->verbose) {
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printf("Variable '%s' from CU '%s' at address 0x%" PRIx64 " encoded\n",
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name, cu->name, addr);
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}
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/* add a BTF_KIND_VAR in encoder->types */
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id = btf_encoder__add_var(encoder, type, name, linkage);
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if (id < 0) {
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err = -1;
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fprintf(stderr, "error: failed to encode variable '%s' at addr 0x%" PRIx64 "\n",
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name, addr);
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break;
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}
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/*
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* add a BTF_VAR_SECINFO in encoder->percpu_secinfo, which will be added into
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* encoder->types later when we add BTF_VAR_DATASEC.
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*/
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id = btf_encoder__add_var_secinfo(encoder, id, addr, size);
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if (id < 0) {
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err = -1;
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fprintf(stderr, "error: failed to encode section info for variable '%s' at addr 0x%" PRIx64 "\n",
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name, addr);
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break;
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}
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}
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if (!encoder->skip_encoding_vars)
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err = btf_encoder__encode_cu_variables(encoder, cu, type_id_off);
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out:
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return err;
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}
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