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xip: Lookup float constants from table to reduce relocations (#894)

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Lookup float/double constants from exec_env->native_symbol table
but not construct them with LLVMBuildConst if XIP mode is enabled,
these constants are introduced by f32/f64.const opcodes and some
float/double conversion opcodes, and make wamrc generate some
relocations in text section of AOT XIP file. This patch eliminates such
relocations when "--enable-indirect-mode" is added to wamrc.
This commit is contained in:
Wenyong Huang
2021-12-16 21:39:23 +08:00
committed by GitHub
parent f2d87ec02e
commit 5be427bfa2
6 changed files with 287 additions and 45 deletions
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112
core/iwasm/compilation/aot_llvm.c
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@ -2004,6 +2004,30 @@ aot_destroy_comp_context(AOTCompContext *comp_ctx)
wasm_runtime_free(comp_ctx);
}
static bool
insert_native_symbol(AOTCompContext *comp_ctx, const char *symbol, int32 idx)
{
AOTNativeSymbol *sym = wasm_runtime_malloc(sizeof(AOTNativeSymbol));
if (!sym) {
aot_set_last_error("alloc native symbol failed.");
return false;
}
memset(sym, 0, sizeof(AOTNativeSymbol));
bh_assert(strlen(symbol) <= sizeof(sym->symbol));
snprintf(sym->symbol, sizeof(sym->symbol), "%s", symbol);
sym->index = idx;
if (BH_LIST_ERROR == bh_list_insert(&comp_ctx->native_symbols, sym)) {
wasm_runtime_free(sym);
aot_set_last_error("insert native symbol to list failed.");
return false;
}
return true;
}
int32
aot_get_native_symbol_index(AOTCompContext *comp_ctx, const char *symbol)
{
@ -2025,22 +2049,30 @@ aot_get_native_symbol_index(AOTCompContext *comp_ctx, const char *symbol)
/* Given symbol is not exist in list, then we alloc a new index for it */
if (idx < 0) {
sym = wasm_runtime_malloc(sizeof(AOTNativeSymbol));
if (!sym) {
aot_set_last_error("alloc native symbol failed.");
return idx;
if (comp_ctx->pointer_size == sizeof(uint32)
&& !strncmp(symbol, "f64#", 4)) {
idx = bh_list_length(&comp_ctx->native_symbols);
/* Add 4 bytes padding on 32-bit target to make sure that
the f64 const is stored on 8-byte aligned address */
if ((idx & 1) && !strncmp(comp_ctx->target_arch, "i386", 4)) {
if (!insert_native_symbol(comp_ctx, "__ignore", idx)) {
return -1;
}
}
}
idx = bh_list_length(&comp_ctx->native_symbols);
sym->symbol = symbol;
sym->index = idx;
if (BH_LIST_ERROR == bh_list_insert(&comp_ctx->native_symbols, sym)) {
wasm_runtime_free(sym);
aot_set_last_error("alloc index for native symbol failed.");
if (!insert_native_symbol(comp_ctx, symbol, idx)) {
return -1;
}
if (comp_ctx->pointer_size == sizeof(uint32)
&& !strncmp(symbol, "f64#", 4)) {
/* f64 const occupies 2 pointer slots on 32-bit target */
if (!insert_native_symbol(comp_ctx, "__ignore", idx + 1)) {
return -1;
}
}
}
return idx;
@ -2445,3 +2477,61 @@ aot_get_func_from_table(const AOTCompContext *comp_ctx, LLVMValueRef base,
fail:
return NULL;
}
LLVMValueRef
aot_load_const_from_table(AOTCompContext *comp_ctx, LLVMValueRef base,
const WASMValue *value, uint8 value_type)
{
LLVMValueRef const_index, const_addr, const_value;
LLVMTypeRef const_ptr_type;
char buf[128] = { 0 };
int32 index;
switch (value_type) {
case VALUE_TYPE_F32:
/* Store the raw int bits of f32 const as a hex string */
snprintf(buf, sizeof(buf), "f32#%08X", value->i32);
const_ptr_type = F32_PTR_TYPE;
break;
case VALUE_TYPE_F64:
/* Store the raw int bits of f64 const as a hex string */
snprintf(buf, sizeof(buf), "f64#%016" PRIx64, value->i64);
const_ptr_type = F64_PTR_TYPE;
break;
default:
bh_assert(0);
return NULL;
}
/* Load f32/f64 const from exec_env->native_symbol[index] */
index = aot_get_native_symbol_index(comp_ctx, buf);
if (index < 0) {
return NULL;
}
if (!(const_index = I32_CONST(index))) {
aot_set_last_error("construct const index failed.");
return NULL;
}
if (!(const_addr = LLVMBuildInBoundsGEP(
comp_ctx->builder, base, &const_index, 1, "const_addr_tmp"))) {
aot_set_last_error("get const addr by index failed.");
return NULL;
}
if (!(const_addr = LLVMBuildBitCast(comp_ctx->builder, const_addr,
const_ptr_type, "const_addr"))) {
aot_set_last_error("cast const fialed.");
return NULL;
}
if (!(const_value =
LLVMBuildLoad(comp_ctx->builder, const_addr, "const_value"))) {
aot_set_last_error("load const failed.");
return NULL;
}
return const_value;
}