codegen.c: resurrect `s->lastpc` to reduce `iseq` scans.
When parsing scripts frequent scans could cost too much.
MODIFY
mrbgems/mruby-compiler/core/codegen.c
mrbgems/mruby-compiler/core/codegen.c
@@ -55,6 +55,7 @@ typedef struct scope {
uint16_t sp;
uint32_t pc;
+ uint32_t lastpc;
uint32_t lastlabel;
int ainfo:15;
mrb_bool mscope:1;
@@ -226,12 +227,14 @@ gen_S(codegen_scope *s, uint16_t i)
static void
genop_0(codegen_scope *s, mrb_code i)
{
+ s->lastpc = s->pc;
gen_B(s, i);
}
static void
genop_1(codegen_scope *s, mrb_code i, uint16_t a)
{
+ s->lastpc = s->pc;
if (a > 0xff) {
gen_B(s, OP_EXT1);
gen_B(s, i);
@@ -246,6 +249,7 @@ genop_1(codegen_scope *s, mrb_code i, uint16_t a)
static void
genop_2(codegen_scope *s, mrb_code i, uint16_t a, uint16_t b)
{
+ s->lastpc = s->pc;
if (a > 0xff && b > 0xff) {
gen_B(s, OP_EXT3);
gen_B(s, i);
@@ -300,6 +304,7 @@ genop_W(codegen_scope *s, mrb_code i, uint32_t a)
uint8_t a2 = (a>>8) & 0xff;
uint8_t a3 = a & 0xff;
+ s->lastpc = s->pc;
gen_B(s, i);
gen_B(s, a1);
gen_B(s, a2);
@@ -468,13 +473,13 @@ rewind_pc(codegen_scope *s)
static struct mrb_insn_data
mrb_last_insn(codegen_scope *s)
{
- return mrb_decode_insn(mrb_prev_pc(s, pc_addr(s)));
+ return mrb_decode_insn(&s->iseq[s->lastpc]);
}
static mrb_bool
no_peephole(codegen_scope *s)
{
- return no_optimize(s) || s->lastlabel == s->pc || s->pc == 0;
+ return no_optimize(s) || s->lastlabel == s->pc || s->pc == 0 || s->pc == s->lastpc;
}
#define JMPLINK_START UINT32_MAX
@@ -500,7 +505,7 @@ genjmp(codegen_scope *s, mrb_code i, uint32_t pc)
{
uint32_t pos;
- gen_B(s, i);
+ genop_0(s, i);
pos = s->pc;
gen_jmpdst(s, pc);
return pos;
@@ -553,11 +558,11 @@ genjmp2(codegen_scope *s, mrb_code i, uint16_t a, uint32_t pc, int val)
if (a > 0xff) {
gen_B(s, OP_EXT1);
- gen_B(s, i);
+ genop_0(s, i);
gen_S(s, a);
}
else {
- gen_B(s, i);
+ genop_0(s, i);
gen_B(s, (uint8_t)a);
}
pos = s->pc;

codegen.c: resurrect `s->lastpc` to reduce `iseq` scans.

When parsing scripts frequent scans could cost too much.