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Refine fast jit backend translation of IR lookupswitch (#1264)

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If the branches of lookupswitch is relatively big, lookup the dst
label address to jump from the address table but not compare
the value of branch one by one.
This commit is contained in:
Wenyong Huang 2022-07-08 12:29:21 +08:00 committed by GitHub
parent de52901583
commit bb9c9a6395
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 96 additions and 20 deletions
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98
core/iwasm/fast-jit/cg/x86-64/jit_codegen_x86_64.cpp
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@ -278,8 +278,10 @@ local_log2l(uint64 data)
/* Jmp type */
typedef enum JmpType {
JMP_DST_LABEL, /* jmp to dst label */
JMP_DST_LABEL_REL, /* jmp to dst label with relative addr */
JMP_DST_LABEL_ABS, /* jmp to dst label with absolute addr */
JMP_END_OF_CALLBC, /* jmp to end of CALLBC */
JMP_LOOKUPSWITCH_BASE, /* LookupSwitch table base addr */
} JmpType;
/**
@ -336,7 +338,7 @@ jmp_from_label_to_label(x86::Assembler &a, bh_list *jmp_info_list,
if (!node)
return false;
node->type = JMP_DST_LABEL;
node->type = JMP_DST_LABEL_REL;
node->label_src = label_src;
node->dst_info.label_dst = label_dst;
node->offset = a.code()->sectionById(0)->buffer().size() + 2;
@ -373,7 +375,7 @@ cmp_r_and_jmp_label(JitCompContext *cc, x86::Assembler &a,
if (!node)
return false;
node->type = JMP_DST_LABEL;
node->type = JMP_DST_LABEL_REL;
node->label_src = label_src;
node->dst_info.label_dst = jit_reg_no(r1);
node->offset = a.code()->sectionById(0)->buffer().size() + 2;
@ -5446,34 +5448,96 @@ lookupswitch_r(JitCompContext *cc, x86::Assembler &a, bh_list *jmp_info_list,
{
JmpInfo *node;
Imm imm;
x86::Mem m;
uint32 i;
int32 label_dst;
int32 label_dst = 0;
char *stream;
if (opnd->match_pairs_num < 10) {
/* For small count of branches, it is better to compare
the key with branch value and jump one by one */
for (i = 0; i < opnd->match_pairs_num; i++) {
imm.setValue(opnd->match_pairs[i].value);
a.cmp(regs_i32[reg_no], imm);
label_dst = jit_reg_no(opnd->match_pairs[i].target);
imm.setValue(label_dst);
node = (JmpInfo *)jit_malloc(sizeof(JmpInfo));
if (!node)
GOTO_FAIL;
node->type = JMP_DST_LABEL;
node->type = JMP_DST_LABEL_REL;
node->label_src = label_src;
node->dst_info.label_dst = label_dst;
node->dst_info.label_dst = jit_reg_no(opnd->match_pairs[i].target);
node->offset = a.code()->sectionById(0)->buffer().size() + 2;
bh_list_insert(jmp_info_list, node);
imm.setValue(INT32_MAX);
a.je(imm);
}
if (opnd->default_target) {
label_dst = jit_reg_no(opnd->default_target);
if (!(is_last_insn && label_is_neighboring(cc, label_src, label_dst)))
if (!(is_last_insn
&& label_is_neighboring(cc, label_src, label_dst)))
JMP_TO_LABEL(label_dst, label_src);
}
}
else {
/* For bigger count of branches, use indirect jump */
/* unsigned extend to rsi */
a.mov(regs_i32[REG_I32_FREE_IDX], regs_i32[reg_no]);
imm.setValue(opnd->match_pairs_num);
a.cmp(regs_i64[REG_I64_FREE_IDX], imm);
/* Jump to default label if rsi >= br_count */
stream = (char *)a.code()->sectionById(0)->buffer().data()
+ a.code()->sectionById(0)->buffer().size();
imm.setValue(INT32_MAX);
a.jb(imm);
*(uint32 *)(stream + 2) = 6;
node = (JmpInfo *)jit_calloc(sizeof(JmpInfo));
if (!node)
goto fail;
node->type = JMP_DST_LABEL_REL;
node->label_src = label_src;
node->dst_info.label_dst = jit_reg_no(opnd->default_target);
node->offset = a.code()->sectionById(0)->buffer().size() + 2;
bh_list_insert(jmp_info_list, node);
imm.setValue(INT32_MAX);
a.jmp(imm);
node = (JmpInfo *)jit_malloc(sizeof(JmpInfo));
if (!node)
GOTO_FAIL;
node->type = JMP_LOOKUPSWITCH_BASE;
node->offset = a.code()->sectionById(0)->buffer().size() + 2;
bh_list_insert(jmp_info_list, node);
/* LookupSwitch table base addr */
imm.setValue(INT64_MAX);
a.mov(regs_i64[reg_no], imm);
/* jmp *(base_addr + rsi * 8) */
m = x86::ptr(regs_i64[reg_no], regs_i64[REG_I64_FREE_IDX], 3);
a.jmp(m);
/* Store each dst label absolute address */
for (i = 0; i < opnd->match_pairs_num; i++) {
node = (JmpInfo *)jit_malloc(sizeof(JmpInfo));
if (!node)
GOTO_FAIL;
node->type = JMP_DST_LABEL_ABS;
node->dst_info.label_dst = jit_reg_no(opnd->match_pairs[i].target);
node->offset = a.code()->sectionById(0)->buffer().size();
bh_list_insert(jmp_info_list, node);
a.embedUInt64(UINT64_MAX);
}
}
return true;
fail:
@ -5774,7 +5838,8 @@ patch_jmp_info_list(JitCompContext *cc, bh_list *jmp_info_list)
stream = (char *)cc->jitted_addr_begin + jmp_info->offset;
if (jmp_info->type == JMP_DST_LABEL) {
if (jmp_info->type == JMP_DST_LABEL_REL) {
/* Jmp with relative address */
reg_dst =
jit_reg_new(JIT_REG_KIND_L32, jmp_info->dst_info.label_dst);
*(int32 *)stream =
@ -5782,10 +5847,21 @@ patch_jmp_info_list(JitCompContext *cc, bh_list *jmp_info_list)
- (uintptr_t)stream)
- 4;
}
else if (jmp_info->type == JMP_DST_LABEL_ABS) {
/* Jmp with absolute address */
reg_dst =
jit_reg_new(JIT_REG_KIND_L32, jmp_info->dst_info.label_dst);
*(uintptr_t *)stream =
(uintptr_t)*jit_annl_jitted_addr(cc, reg_dst);
}
else if (jmp_info->type == JMP_END_OF_CALLBC) {
/* 7 is the size of mov and jmp instruction */
*(uintptr_t *)stream = (uintptr_t)stream + sizeof(uintptr_t) + 7;
}
else if (jmp_info->type == JMP_LOOKUPSWITCH_BASE) {
/* 11 is the size of 8-byte addr and 3-byte jmp instruction */
*(uintptr_t *)stream = (uintptr_t)stream + 11;
}
jmp_info = jmp_info_next;
}