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details about jump optimization

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This commit is contained in:
Roberto Ierusalimschy 2002-05-13 10:07:48 -03:00
parent 2dadc81822
commit b55fded18c
2 changed files with 24 additions and 14 deletions
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35
lcode.c
View File

@ -1,5 +1,5 @@
/*
** $Id: lcode.c,v 1.101 2002/05/10 17:02:32 roberto Exp roberto $
** $Id: lcode.c,v 1.102 2002/05/10 19:22:11 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@ -75,12 +75,6 @@ int luaK_getlabel (FuncState *fs) {
}
void luaK_dischargejpc (FuncState *fs) {
luaK_patchlist(fs, fs->jpc, fs->pc); /* discharge old list `jpc' */
fs->jpc = NO_JUMP;
}
static int luaK_getjump (FuncState *fs, int pc) {
int offset = GETARG_sBx(fs->f->code[pc]);
if (offset == NO_JUMP) /* point to itself represents end of list */
@ -144,9 +138,19 @@ static void luaK_patchlistaux (FuncState *fs, int list,
}
void luaK_dischargejpc (FuncState *fs) {
luaK_patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc, NO_REG, fs->pc);
fs->jpc = NO_JUMP;
}
void luaK_patchlist (FuncState *fs, int list, int target) {
lua_assert(target <= fs->pc);
luaK_patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
if (target == fs->pc)
luaK_patchtohere(fs, list);
else {
lua_assert(target < fs->pc);
luaK_patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
}
}
@ -342,12 +346,12 @@ static void luaK_exp2reg (FuncState *fs, expdesc *e, int reg) {
int p_f = NO_JUMP; /* position of an eventual LOAD false */
int p_t = NO_JUMP; /* position of an eventual LOAD true */
if (need_value(fs, e->t, 1) || need_value(fs, e->f, 0)) {
if (e->k != VJMP) {
luaK_getlabel(fs); /* this instruction may be a jump target */
luaK_codeAsBx(fs, OP_JMP, 0, 2); /* to jump over both pushes */
}
int fj = NO_JUMP; /* first jump (over LOAD ops.) */
if (e->k != VJMP)
fj = luaK_jump(fs);
p_f = code_label(fs, reg, 0, 1);
p_t = code_label(fs, reg, 1, 0);
luaK_patchtohere(fs, fj);
}
final = luaK_getlabel(fs);
luaK_patchlistaux(fs, e->f, p_f, NO_REG, final, reg, p_f);
@ -724,6 +728,11 @@ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
}
void luaK_fixline (FuncState *fs, int line) {
fs->f->lineinfo[fs->pc - 1] = line;
}
int luaK_code (FuncState *fs, Instruction i, int line) {
Proto *f = fs->f;
int oldsize = f->sizecode;

3
lcode.h
View File

@ -1,5 +1,5 @@
/*
** $Id: lcode.h,v 1.34 2002/05/10 17:02:32 roberto Exp roberto $
** $Id: lcode.h,v 1.35 2002/05/10 19:22:11 roberto Exp $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@ -44,6 +44,7 @@ typedef enum UnOpr { OPR_MINUS, OPR_NOT, OPR_NOUNOPR } UnOpr;
int luaK_code (FuncState *fs, Instruction i, int line);
int luaK_codeABx (FuncState *fs, OpCode o, int A, unsigned int Bx);
int luaK_codeABC (FuncState *fs, OpCode o, int A, int B, int C);
void luaK_fixline (FuncState *fs, int line);
void luaK_nil (FuncState *fs, int from, int n);
void luaK_reserveregs (FuncState *fs, int n);
int luaK_stringK (FuncState *fs, TString *s);