commit b487975344ee90c0410e79e1af08461bdbc0f3da
parent 94e5545806515bc830982dedc4966bd2756a023e
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 10 May 2002 14:02:10 -0300
optimization for `while' (first version)
Diffstat:
M | lcode.c | | | 27 | +++++++++++++++++---------- |
M | lcode.h | | | 5 | ++++- |
M | lparser.c | | | 47 | +++++++++++++++++++++++++++++++++++++++++++---- |
3 files changed, 64 insertions(+), 15 deletions(-)
diff --git a/lcode.c b/lcode.c
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.c,v 1.99 2002/05/07 17:36:56 roberto Exp roberto $
+** $Id: lcode.c,v 1.100 2002/05/09 14:14:34 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -39,6 +39,13 @@ void luaK_nil (FuncState *fs, int from, int n) {
}
+void luaK_moveexp (expdesc *e, int offset) {
+ if (e->t != NO_JUMP) e->t += offset;
+ if (e->f != NO_JUMP) e->f += offset;
+ if (e->k == VRELOCABLE || e->k == VJMP) e->info += offset;
+}
+
+
int luaK_jump (FuncState *fs) {
int j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
if (j == fs->lasttarget) { /* possible jumps to this jump? */
@@ -515,12 +522,10 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) {
}
}
luaK_concat(fs, &e->f, pc); /* insert last jump in `f' list */
- luaK_patchtohere(fs, e->t);
- e->t = NO_JUMP;
}
-static void luaK_goiffalse (FuncState *fs, expdesc *e) {
+void luaK_goiffalse (FuncState *fs, expdesc *e) {
int pc; /* pc of last jump */
luaK_dischargevars(fs, e);
switch (e->k) {
@@ -542,8 +547,6 @@ static void luaK_goiffalse (FuncState *fs, expdesc *e) {
}
}
luaK_concat(fs, &e->t, pc); /* insert last jump in `t' list */
- luaK_patchtohere(fs, e->f);
- e->f = NO_JUMP;
}
@@ -607,10 +610,14 @@ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
switch (op) {
case OPR_AND: {
luaK_goiftrue(fs, v);
+ luaK_patchtohere(fs, v->t);
+ v->t = NO_JUMP;
break;
}
case OPR_OR: {
luaK_goiffalse(fs, v);
+ luaK_patchtohere(fs, v->f);
+ v->f = NO_JUMP;
break;
}
case OPR_CONCAT: {
@@ -727,7 +734,7 @@ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
}
-static int luaK_code (FuncState *fs, Instruction i) {
+int luaK_code (FuncState *fs, Instruction i, int line) {
Proto *f = fs->f;
int oldsize = f->sizecode;
/* put new instruction in code array */
@@ -736,19 +743,19 @@ static int luaK_code (FuncState *fs, Instruction i) {
f->code[fs->pc] = i;
if (f->sizecode != oldsize)
luaM_reallocvector(fs->L, f->lineinfo, oldsize, f->sizecode, int);
- f->lineinfo[fs->pc] = fs->ls->lastline;
+ f->lineinfo[fs->pc] = line;
return fs->pc++;
}
int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
lua_assert(getOpMode(o) == iABC);
- return luaK_code(fs, CREATE_ABC(o, a, b, c));
+ return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline);
}
int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
- return luaK_code(fs, CREATE_ABx(o, a, bc));
+ return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline);
}
diff --git a/lcode.h b/lcode.h
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.h,v 1.32 2002/04/24 20:07:46 roberto Exp roberto $
+** $Id: lcode.h,v 1.33 2002/05/07 17:36:56 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -41,6 +41,7 @@ typedef enum UnOpr { OPR_MINUS, OPR_NOT, OPR_NOUNOPR } UnOpr;
#define luaK_codeAsBx(fs,o,A,sBx) luaK_codeABx(fs,o,A,(sBx)+MAXARG_sBx)
+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_nil (FuncState *fs, int from, int n);
@@ -54,7 +55,9 @@ void luaK_exp2val (FuncState *fs, expdesc *e);
int luaK_exp2RK (FuncState *fs, expdesc *e);
void luaK_self (FuncState *fs, expdesc *e, expdesc *key);
void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k);
+void luaK_moveexp (expdesc *e, int offset);
void luaK_goiftrue (FuncState *fs, expdesc *e);
+void luaK_goiffalse (FuncState *fs, expdesc *e);
void luaK_storevar (FuncState *fs, expdesc *var, expdesc *e);
void luaK_setcallreturns (FuncState *fs, expdesc *var, int nresults);
int luaK_jump (FuncState *fs);
diff --git a/lparser.c b/lparser.c
@@ -1,5 +1,5 @@
/*
-** $Id: lparser.c,v 1.178 2002/04/24 20:07:46 roberto Exp roberto $
+** $Id: lparser.c,v 1.179 2002/05/07 17:36:56 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -946,22 +946,61 @@ static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
static void cond (LexState *ls, expdesc *v) {
/* cond -> exp */
expr(ls, v); /* read condition */
+ if (v->k == VNIL) v->k = VFALSE; /* `falses' are all equal here */
luaK_goiftrue(ls->fs, v);
+ luaK_patchtohere(ls->fs, v->t);
}
+/*
+** The while statement optimizes its code by coding the condition
+** after its body (and thus avoiding one jump in the loop).
+*/
+
+/*
+** maximum size of expressions for optimizing `while' code
+*/
+#ifndef MAXEXPWHILE
+#define MAXEXPWHILE 100
+#endif
+
+/*
+** the call `luaK_goiffalse' may grow the size of an expression by
+** at most this:
+*/
+#define EXTRAEXP 5
+
static void whilestat (LexState *ls, int line) {
/* whilestat -> WHILE cond DO block END */
+ Instruction codeexp[MAXEXPWHILE + EXTRAEXP];
+ int lineexp = 0;
+ int i;
+ int sizeexp;
FuncState *fs = ls->fs;
int while_init = luaK_getlabel(fs);
expdesc v;
BlockCnt bl;
- enterblock(fs, &bl, 1);
next(ls);
- cond(ls, &v);
+ expr(ls, &v);
+ if (v.k == VK) v.k = VTRUE; /* `trues' are all equal here */
+ lineexp = ls->linenumber;
+ luaK_goiffalse(fs, &v);
+ sizeexp = fs->pc - while_init;
+ if (sizeexp > MAXEXPWHILE)
+ luaX_syntaxerror(ls, "while condition too complex");
+ fs->pc = while_init; /* remove `exp' code */
+ luaK_getlabel(fs);
+ for (i = 0; i < sizeexp; i++) /* save `exp' code */
+ codeexp[i] = fs->f->code[while_init + i];
+ luaK_jump(fs);
+ enterblock(fs, &bl, 1);
check(ls, TK_DO);
block(ls);
- luaK_patchlist(fs, luaK_jump(fs), while_init);
+ luaK_patchtohere(fs, while_init); /* initial jump jumps to here */
+ luaK_moveexp(&v, fs->pc - while_init); /* correct pointers */
+ for (i=0; i<sizeexp; i++)
+ luaK_code(fs, codeexp[i], lineexp);
+ luaK_patchlist(fs, v.t, while_init+1);
luaK_patchtohere(fs, v.f);
check_match(ls, TK_END, TK_WHILE, line);
leaveblock(fs);