With only a single encoder, it's now easier to acummulate function
states into an array, and then sort it before merging the states and
adding the functions to BTF.
Previously a list (per encoder) was collected, and because the sorting
is required, the lists had to be converted into a temporary array in a
separate step.
Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxx>
---
btf_encoder.c | 95 ++++++++++++++++++++++++++++++---------------------
1 file changed, 57 insertions(+), 38 deletions(-)
diff --git a/btf_encoder.c b/btf_encoder.c
index da99fbb..78efd70 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -72,7 +72,6 @@ struct btf_encoder_func_annot {
/* state used to do later encoding of saved functions */
struct btf_encoder_func_state {
- struct list_head node;
struct btf_encoder *encoder;
struct elf_function *elf;
uint32_t type_id_off;
@@ -134,7 +133,11 @@ struct btf_encoder {
struct elf_secinfo *secinfo;
size_t seccnt;
int encode_vars;
- struct list_head func_states;
+ struct {
+ struct btf_encoder_func_state *array;
+ int cnt;
+ int cap;
+ } func_states;
/* This is a list of elf_functions tables, one per ELF.
* Multiple ELF modules can be processed in one pahole run,
* so we have to store elf_functions tables per ELF.
@@ -1078,9 +1081,31 @@ static bool funcs__match(struct btf_encoder_func_state *s1,
return true;
}
+static struct btf_encoder_func_state *btf_encoder__alloc_func_state(struct btf_encoder *encoder)
+{
+ struct btf_encoder_func_state *tmp;
+
+ if (encoder->func_states.cnt >= encoder->func_states.cap) {
+
+ /* We only need to grow to accommodate duplicate
+ * function declarations across different CUs, so the
+ * rate of the array growth shouldn't be high.
+ */
+ encoder->func_states.cap += 64;
+
+ tmp = realloc(encoder->func_states.array, sizeof(*tmp) * encoder->func_states.cap);
+ if (!tmp)
+ return NULL;
+
+ encoder->func_states.array = tmp;
+ }
+
+ return &encoder->func_states.array[encoder->func_states.cnt++];
+}
+
static int32_t btf_encoder__save_func(struct btf_encoder *encoder, struct function *fn, struct elf_function *func)
{
- struct btf_encoder_func_state *state = zalloc(sizeof(*state));
+ struct btf_encoder_func_state *state = btf_encoder__alloc_func_state(encoder);
struct ftype *ftype = &fn->proto;
struct btf *btf = encoder->btf;
struct llvm_annotation *annot;
@@ -1142,7 +1167,6 @@ static int32_t btf_encoder__save_func(struct btf_encoder *encoder, struct functi
idx++;
}
}
- list_add_tail(&state->node, &encoder->func_states);
return 0;
out:
zfree(&state->annots);
@@ -1219,17 +1243,15 @@ static int functions_cmp(const void *_a, const void *_b)
static int saved_functions_cmp(const void *_a, const void *_b)
{
- struct btf_encoder_func_state * const *a = _a;
- struct btf_encoder_func_state * const *b = _b;
+ const struct btf_encoder_func_state *a = _a;
+ const struct btf_encoder_func_state *b = _b;
- return functions_cmp((*a)->elf, (*b)->elf);
+ return functions_cmp(a->elf, b->elf);
}
-static int saved_functions_combine(void *_a, void *_b)
+static int saved_functions_combine(struct btf_encoder_func_state *a, struct btf_encoder_func_state *b)
{
uint8_t optimized, unexpected, inconsistent;
- struct btf_encoder_func_state *a = _a;
- struct btf_encoder_func_state *b = _b;
int ret;
ret = strncmp(a->elf->name, b->elf->name,
@@ -1250,44 +1272,37 @@ static int saved_functions_combine(void *_a, void *_b)
static void btf_encoder__delete_saved_funcs(struct btf_encoder *encoder)
{
- struct btf_encoder_func_state *pos, *s;
+ struct btf_encoder_func_state *state;
- list_for_each_entry_safe(pos, s, &encoder->func_states, node) {
- list_del(&pos->node);
- free(pos->parms);
- free(pos->annots);
- free(pos);
+ for (int i = 0; i < encoder->func_states.cnt; i++) {
+ state = &encoder->func_states.array[i];
+ free(state->parms);
+ free(state->annots);
}
+
+ free(encoder->func_states.array);
+
+ encoder->func_states.array = NULL;
+ encoder->func_states.cnt = 0;
+ encoder->func_states.cap = 0;
}
static int btf_encoder__add_saved_funcs(struct btf_encoder *encoder, bool skip_encoding_inconsistent_proto)
{
- struct btf_encoder_func_state **saved_fns = NULL, *s;
- int err = 0, i = 0, j, nr_saved_fns = 0;
-
- /* Retrieve function states from the encoder, combine them
- * and sort by name, addr.
- */
- list_for_each_entry(s, &encoder->func_states, node) {
- nr_saved_fns++;
- }
+ struct btf_encoder_func_state *saved_fns = encoder->func_states.array;
+ int nr_saved_fns = encoder->func_states.cnt;
+ int err = 0, i = 0, j;
if (nr_saved_fns == 0)
goto out;
- saved_fns = calloc(nr_saved_fns, sizeof(*saved_fns));
- if (!saved_fns) {
- err = -ENOMEM;
- goto out;
- }
-
- list_for_each_entry(s, &encoder->func_states, node) {
- saved_fns[i++] = s;
- }
+ /* Sort the saved_fns so that we can merge multiple states of
+ * the "same" function into one, before adding it to the BTF.
+ */
qsort(saved_fns, nr_saved_fns, sizeof(*saved_fns), saved_functions_cmp);
for (i = 0; i < nr_saved_fns; i = j) {
- struct btf_encoder_func_state *state = saved_fns[i];
+ struct btf_encoder_func_state *state = &saved_fns[i];
bool add_to_btf = !skip_encoding_inconsistent_proto;
/* Compare across sorted functions that match by name/prefix;
@@ -1295,7 +1310,7 @@ static int btf_encoder__add_saved_funcs(struct btf_encoder *encoder, bool skip_e
*/
j = i + 1;
- while (j < nr_saved_fns && saved_functions_combine(saved_fns[i], saved_fns[j]) == 0)
+ while (j < nr_saved_fns && saved_functions_combine(&saved_fns[i], &saved_fns[j]) == 0)
j++;
/* do not exclude functions with optimized-out parameters; they
@@ -1313,7 +1328,6 @@ static int btf_encoder__add_saved_funcs(struct btf_encoder *encoder, bool skip_e
}
out:
- free(saved_fns);
btf_encoder__delete_saved_funcs(encoder);
return err;
@@ -2404,7 +2418,7 @@ struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filenam
encoder->need_index_type = false;
encoder->array_index_id = 0;
encoder->encode_vars = 0;
- INIT_LIST_HEAD(&encoder->func_states);
+
if (!conf_load->skip_encoding_btf_vars)
encoder->encode_vars |= BTF_VAR_PERCPU;
if (conf_load->encode_btf_global_vars)
@@ -2417,6 +2431,11 @@ struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filenam
encoder->symtab = funcs->symtab;
+ /* Start with funcs->cnt. The array may grow in btf_encoder__alloc_func_state() */
+ encoder->func_states.array = zalloc(sizeof(*encoder->func_states.array) * funcs->cnt);
+ encoder->func_states.cap = funcs->cnt;
+ encoder->func_states.cnt = 0;
+
GElf_Ehdr ehdr;
if (gelf_getehdr(cu->elf, &ehdr) == NULL) {
--
2.47.1
