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perf(wamrc): Replace slow symbol lookup with hash map in wamrc #4912

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perf(wamrc): Replace slow symbol lookup with hash map in wamrc #4912

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114 changes: 82 additions & 32 deletions core/iwasm/compilation/aot_emit_aot_file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@ typedef struct AOTSymbolList {
AOTSymbolNode *head;
AOTSymbolNode *end;
uint32 len;
void *hash_table;
} AOTSymbolList;

/* AOT object data */
Expand Down Expand Up @@ -989,46 +990,81 @@ get_relocation_groups_size(AOTObjectData *obj_data,
return size;
}

/* return the index (in order of insertion) of the symbol,
create if not exits, -1 if failed */
#define SYMBOL_HASH_SIZE 4096
#define SYMBOL_HASH_MASK (SYMBOL_HASH_SIZE - 1)

typedef struct AOTSymbolHashEntry {
const char *symbol;
uint32 index;
struct AOTSymbolHashEntry *hash_next;
} AOTSymbolHashEntry;

static uint32
get_relocation_symbol_index(const char *symbol_name, bool *is_new,
AOTSymbolList *symbol_list)
{
AOTSymbolNode *sym;
uint32 index = 0;

sym = symbol_list->head;
while (sym) {
if (!strcmp(sym->symbol, symbol_name)) {
if (is_new)
*is_new = false;
return index;
uint32 index;
AOTSymbolHashEntry **ht;
if (!symbol_list->hash_table) {
symbol_list->hash_table = wasm_runtime_malloc(
sizeof(AOTSymbolHashEntry *) * SYMBOL_HASH_SIZE);
if (symbol_list->hash_table)
memset(symbol_list->hash_table, 0,
sizeof(AOTSymbolHashEntry *) * SYMBOL_HASH_SIZE);
}
ht = (AOTSymbolHashEntry **)symbol_list->hash_table;
if (ht) {
uint32 bucket = wasm_string_hash(symbol_name) & SYMBOL_HASH_MASK;
AOTSymbolHashEntry *entry = ht[bucket];
while (entry) {
if (!strcmp(entry->symbol, symbol_name)) {
if (is_new)
*is_new = false;
return entry->index;
}
entry = entry->hash_next;
}

sym = sym->next;
index++;
}

/* Not found in symbol_list, add it */
sym = wasm_runtime_malloc(sizeof(AOTSymbolNode));
if (!sym) {
return (uint32)-1;
}

memset(sym, 0, sizeof(AOTSymbolNode));
sym->symbol = (char *)symbol_name;
sym->str_len = (uint32)strlen(symbol_name);

if (!symbol_list->head) {
symbol_list->head = symbol_list->end = sym;
}
else {
symbol_list->end->next = sym;
symbol_list->end = sym;
AOTSymbolNode *sym = symbol_list->head;
uint32 idx = 0;
while (sym) {
if (!strcmp(sym->symbol, symbol_name)) {
if (is_new)
*is_new = false;
return idx;
}
sym = sym->next;
idx++;
}
}
index = symbol_list->len;
{
AOTSymbolNode *sym = wasm_runtime_malloc(sizeof(AOTSymbolNode));
if (!sym)
return (uint32)-1;
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@lum1n0us lum1n0us May 13, 2026

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symbol_list->len is 0 and hash_table points to a allocation and aot_obj_data_destroy() only releases has_table if symbol_list.len != 0. There will be a leak.

memset(sym, 0, sizeof(AOTSymbolNode));
sym->symbol = (char *)symbol_name;
sym->str_len = (uint32)strlen(symbol_name);
if (!symbol_list->head)
symbol_list->head = symbol_list->end = sym;
else {
symbol_list->end->next = sym;
symbol_list->end = sym;
}
symbol_list->len++;
}
if (ht) {
uint32 bucket = wasm_string_hash(symbol_name) & SYMBOL_HASH_MASK;
AOTSymbolHashEntry *entry =
wasm_runtime_malloc(sizeof(AOTSymbolHashEntry));
if (!entry)
return (uint32)-1;
entry->symbol = symbol_name;
entry->index = index;
entry->hash_next = ht[bucket];
ht[bucket] = entry;
}
symbol_list->len++;

if (is_new)
*is_new = true;
return index;
Expand Down Expand Up @@ -4324,6 +4360,20 @@ destroy_relocation_symbol_list(AOTSymbolList *symbol_list)
wasm_runtime_free(elem);
elem = next;
}
if (symbol_list->hash_table) {
AOTSymbolHashEntry **ht =
(AOTSymbolHashEntry **)symbol_list->hash_table;
uint32 i;
for (i = 0; i < SYMBOL_HASH_SIZE; i++) {
AOTSymbolHashEntry *entry = ht[i];
while (entry) {
AOTSymbolHashEntry *next = entry->hash_next;
wasm_runtime_free(entry);
entry = next;
}
}
wasm_runtime_free(ht);
}
}

void
Expand Down
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