Do not collect functions from ELF for each new btf_encoder, and
instead set a pointer to a shared elf_functions table, built
beforehand by btf_encoder__pre_cus__load_module().
Change the algorithm of btf_encoder__add_saved_funcs(): traverse
elf_functions table once, merge function state for each list of
elf_function, and add each function to the BTF of the owner of the
first elf_function of the list.
Do not call btf_encoder__add_saved_funcs() on every
btf_encoder__add_encoder(). Instead, introduce
btf_encoder__merge_encoders() function that does that once.
Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxx>
---
btf_encoder.c | 113 +++++++++++++++++++++++++++-----------------------
btf_encoder.h | 3 +-
pahole.c | 25 ++++++-----
3 files changed, 78 insertions(+), 63 deletions(-)
diff --git a/btf_encoder.c b/btf_encoder.c
index f88c2e1..07d2031 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -140,7 +140,7 @@ struct btf_encoder {
struct elf_secinfo *secinfo;
size_t seccnt;
int encode_vars;
- struct elf_functions functions;
+ struct elf_functions *functions;
};
struct btf_func {
@@ -243,8 +243,6 @@ int btf_encoder__pre_cus__load_module(struct process_dwflmod_parms *parms, Dwfl_
static LIST_HEAD(encoders);
static pthread_mutex_t encoders__lock = PTHREAD_MUTEX_INITIALIZER;
-static int btf_encoder__add_saved_funcs(struct btf_encoder *encoder);
-
/* mutex only needed for add/delete, as this can happen in multiple encoding
* threads. Traversal of the list is currently confined to thread collection.
*/
@@ -890,14 +888,12 @@ static int32_t btf_encoder__add_var_secinfo(struct btf_encoder *encoder, size_t
return gobuffer__add(&encoder->secinfo[shndx].secinfo, &si, sizeof(si));
}
-int32_t btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other)
+static int32_t btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other)
{
size_t shndx;
if (encoder == other)
return 0;
- btf_encoder__add_saved_funcs(other);
-
for (shndx = 1; shndx < other->seccnt; shndx++) {
struct gobuffer *var_secinfo_buf = &other->secinfo[shndx].secinfo;
size_t sz = gobuffer__size(var_secinfo_buf);
@@ -925,6 +921,25 @@ int32_t btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder
return btf__add_btf(encoder->btf, other->btf);
}
+int btf_encoder__merge_encoders(struct btf_encoder *base_encoder, struct btf_encoder **encoders, int nr_encoders)
+{
+ int err;
+
+ err = btf_encoder__add_saved_funcs(base_encoder);
+ if (err < 0)
+ return err;
+
+ for (int i = 0; i < nr_encoders; i++) {
+ if (base_encoder == encoders[i])
+ continue;
+ err = btf_encoder__add_encoder(base_encoder, encoders[i]);
+ if (err < 0)
+ return err;
+ }
+
+ return 0;
+}
+
static int32_t btf_encoder__add_datasec(struct btf_encoder *encoder, size_t shndx)
{
struct gobuffer *var_secinfo_buf = &encoder->secinfo[shndx].secinfo;
@@ -991,7 +1006,7 @@ static int32_t btf_encoder__add_decl_tag(struct btf_encoder *encoder, const char
return id;
}
-static void btf_encoder__log_func_skip(struct btf_encoder *encoder, struct elf_function *func,
+static void btf_encoder__log_func_skip(const struct btf_encoder *encoder, struct elf_function *func,
const char *fmt, ...)
{
va_list ap;
@@ -1027,7 +1042,7 @@ static int fwd__kind(const struct btf_type *t)
return btf_kind(t);
}
-static bool types__match(struct btf_encoder *encoder,
+static bool types__match(const struct btf_encoder *encoder,
struct btf *btf1, int type_id1,
struct btf *btf2, int type_id2)
{
@@ -1126,7 +1141,7 @@ static bool types__match(struct btf_encoder *encoder,
return false;
}
-static bool funcs__match(struct btf_encoder *encoder, struct elf_function *func,
+static bool funcs__match(const struct btf_encoder *encoder, struct elf_function *func,
struct btf *btf1, struct btf_encoder_func_state *s1,
struct btf *btf2, struct btf_encoder_func_state *s2)
{
@@ -1340,44 +1355,51 @@ static inline struct elf_function *find_elf_function_in_list(struct elf_function
return NULL;
}
-static int btf_encoder__add_saved_funcs(struct btf_encoder *encoder)
+
+// Each element of elf_functions->entries is a list of a variable
+// number of elf_function structs, because not all encoders saved a
+// particular function. However each function saved by at least one
+// encoder needs to be added to BTF _somewhere_. Here we traverse the
+// entire elf_functions table, and for each list of elf_function
+// structs a function is added to the BTF of the encoder of the first
+// elf_function in the list.
+int btf_encoder__add_saved_funcs(struct btf_encoder *base_encoder)
{
- int i;
+ struct elf_functions *functions = base_encoder->functions;
- for (i = 0; i < encoder->functions.cnt; i++) {
- struct elf_function *func = find_elf_function_in_list(&encoder->functions.entries[i], encoder);
+ for (int i = 0; i < functions->cnt; i++) {
+ struct elf_function *list_head = &functions->entries[i];
+ struct btf_encoder_func_state *state;
+ struct elf_function *func;
- if (!func)
+ // list_head without an owner means no encoder
+ // has saved a function with this name
+ if (!list_head->owner)
continue;
- struct btf_encoder_func_state *state = &func->state;
- struct btf_encoder *other_encoder = NULL;
+ func = list_head;
+ state = &func->state;
if (!state->initialized || state->processed)
continue;
- /* merge optimized-out status across encoders; since each
- * encoder has the same elf symbol table we can use the
- * same index to access the same elf symbol.
- */
- btf_encoders__for_each_encoder(other_encoder) {
- struct elf_function *other_func;
- struct btf_encoder_func_state *other_state;
- uint8_t optimized, unexpected, inconsistent;
- other_func = find_elf_function_in_list(&other_encoder->functions.entries[i], other_encoder);
- if (other_encoder == encoder || !other_func)
+ for_each_elf_function(other_func, list_head) {
+ if (func == other_func)
continue;
- other_state = &other_func->state;
- if (!other_state->initialized)
+ struct btf_encoder_func_state *other_state = &other_func->state;
+ uint8_t optimized, unexpected, inconsistent;
+
+ if (!other_func || !other_state->initialized || other_state->processed)
continue;
+
optimized = state->optimized_parms | other_state->optimized_parms;
unexpected = state->unexpected_reg | other_state->unexpected_reg;
inconsistent = state->inconsistent_proto | other_state->inconsistent_proto;
if (!unexpected && !inconsistent &&
- !funcs__match(encoder, func,
- encoder->btf, state,
- other_encoder->btf, other_state))
+ !funcs__match(func->owner, func,
+ func->owner->btf, state,
+ other_func->owner->btf, other_state))
inconsistent = 1;
state->optimized_parms = other_state->optimized_parms = optimized;
state->unexpected_reg = other_state->unexpected_reg = unexpected;
@@ -1391,7 +1413,7 @@ static int btf_encoder__add_saved_funcs(struct btf_encoder *encoder)
* unexpected register use or multiple inconsistent prototypes.
*/
if (!state->unexpected_reg && !state->inconsistent_proto) {
- if (btf_encoder__add_func(encoder, NULL, func))
+ if (btf_encoder__add_func((struct btf_encoder *)func->owner, NULL, func))
return -1;
}
state->processed = 1;
@@ -1442,8 +1464,8 @@ static struct elf_function *btf_encoder__find_function(const struct btf_encoder
{
struct elf_function key = { .name = name, .prefixlen = prefixlen };
struct elf_function *head = bsearch(&key,
- encoder->functions.entries,
- encoder->functions.cnt,
+ encoder->functions->entries,
+ encoder->functions->cnt,
sizeof(key),
functions_cmp);
struct elf_function *func = NULL;
@@ -2169,9 +2191,6 @@ int btf_encoder__encode(struct btf_encoder *encoder)
int err;
size_t shndx;
- /* for single-threaded case, saved funcs are added here */
- btf_encoder__add_saved_funcs(encoder);
-
for (shndx = 1; shndx < encoder->seccnt; shndx++)
if (gobuffer__size(&encoder->secinfo[shndx].secinfo))
btf_encoder__add_datasec(encoder, shndx);
@@ -2222,11 +2241,8 @@ int btf_encoder__encode(struct btf_encoder *encoder)
err = btf_encoder__write_elf(encoder, encoder->btf, BTF_ELF_SEC);
}
- // TODO: after moving encoders to shared elf_functions,
- // replace elf_functions__get(encoder->functions.elf) here
- // with encoder->functions
- // The pointer to shared elf_functions will be set in btf_encoder__new
- elf_functions__delete(elf_functions__get(encoder->functions.elf));
+ // Delete the shared elf_functions table, because we are done encoding
+ elf_functions__delete(encoder->functions);
return err;
}
@@ -2525,8 +2541,7 @@ struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filenam
printf("%s: '%s' doesn't have symtab.\n", __func__, cu->filename);
goto out;
}
- encoder->functions.symtab = encoder->symtab;
- encoder->functions.elf = cu->elf;
+ encoder->functions = elf_functions__get(cu->elf);
/* index the ELF sections for later lookup */
@@ -2565,9 +2580,6 @@ struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filenam
if (!found_percpu && encoder->verbose)
printf("%s: '%s' doesn't have '%s' section\n", __func__, cu->filename, PERCPU_SECTION);
- if (elf_functions__collect(&encoder->functions))
- goto out_delete;
-
if (encoder->verbose)
printf("File %s:\n", cu->filename);
btf_encoders__add(encoder);
@@ -2593,8 +2605,7 @@ void btf_encoder__delete(struct btf_encoder *encoder)
zfree(&encoder->source_filename);
btf__free(encoder->btf);
encoder->btf = NULL;
-
- __elf_functions__delete(&encoder->functions);
+ elf_symtab__delete(encoder->symtab);
free(encoder);
@@ -2694,7 +2705,7 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
continue;
if (!ftype__has_arg_names(&fn->proto))
continue;
- if (encoder->functions.cnt) {
+ if (encoder->functions->cnt) {
const char *name;
name = function__name(fn);
@@ -2710,7 +2721,7 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
save = true;
else
func->generated = true;
- } else if (encoder->functions.suffix_cnt &&
+ } else if (encoder->functions->suffix_cnt &&
conf_load->btf_gen_optimized) {
/* falling back to name.isra.0 match if no exact
* match is found; only bother if we found any
diff --git a/btf_encoder.h b/btf_encoder.h
index 7bfc994..2fb4fc6 100644
--- a/btf_encoder.h
+++ b/btf_encoder.h
@@ -32,7 +32,8 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
struct btf *btf_encoder__btf(struct btf_encoder *encoder);
-int btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other);
+int btf_encoder__add_saved_funcs(struct btf_encoder *encoder);
+int btf_encoder__merge_encoders(struct btf_encoder *base_encoder, struct btf_encoder **encoders, int nr_encoders);
int btf_encoder__pre_cus__load_module(struct process_dwflmod_parms *parms, Dwfl_Module *mod, Dwarf *dw, Elf *elf);
diff --git a/pahole.c b/pahole.c
index 0ff6bc2..a45aa7a 100644
--- a/pahole.c
+++ b/pahole.c
@@ -3256,23 +3256,23 @@ static int pahole_threads_collect(struct conf_load *conf, int nr_threads, void *
int error)
{
struct thread_data **threads = (struct thread_data **)thr_data;
+ struct btf_encoder *encoders[nr_threads];
int i;
int err = 0;
if (error)
goto out;
- for (i = 0; i < nr_threads; i++) {
- /*
- * Merge content of the btf instances of worker threads to the btf
- * instance of the primary btf_encoder.
- */
- if (!threads[i]->btf)
- continue;
- err = btf_encoder__add_encoder(btf_encoder, threads[i]->encoder);
- if (err < 0)
- goto out;
- }
+ for (i = 0; i < nr_threads; i++)
+ encoders[i] = threads[i]->encoder;
+
+ /*
+ * Merge content of the btf instances of worker threads to the btf
+ * instance of the primary btf_encoder.
+ */
+ err = btf_encoder__merge_encoders(btf_encoder, encoders, nr_threads);
+ if (err < 0)
+ goto out;
err = 0;
out:
@@ -3915,6 +3915,9 @@ try_sole_arg_as_class_names:
exit(1);
}
+ if (conf_load.nr_jobs <= 1 || conf_load.reproducible_build)
+ btf_encoder__add_saved_funcs(btf_encoder);
+
err = btf_encoder__encode(btf_encoder);
if (err) {
fputs("Failed to encode BTF\n", stderr);
--
2.43.0
