commit 2e1b32d87339c22b0518481fa260edf3bfbc01d3
parent 89a3ec08f37d127fc3c7756cb7cf71586959f8c4
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 16 Jun 2000 14:51:18 -0300
optimizations for "while 1", "until nil", and the like
Diffstat:
| M | lcode.c | | | 153 | ++++++++++++++++++++++++++++++++++++++++++++++++++++--------------------------- |
| M | lcode.h | | | 3 | +-- |
2 files changed, 102 insertions(+), 54 deletions(-)
diff --git a/lcode.c b/lcode.c
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.c,v 1.34 2000/06/05 14:56:18 roberto Exp roberto $
+** $Id: lcode.c,v 1.35 2000/06/12 13:52:05 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -268,20 +268,29 @@ void luaK_concat (FuncState *fs, int *l1, int l2) {
static void luaK_testgo (FuncState *fs, expdesc *v, int invert, OpCode jump) {
+ int prevpos; /* position of last instruction */
Instruction *previous;
- int *golist = &v->u.l.f;
- int *exitlist = &v->u.l.t;
- if (invert) { /* interchange `golist' and `exitlist' */
- int *temp = golist; golist = exitlist; exitlist = temp;
+ int *golist, *exitlist;
+ if (!invert) {
+ golist = &v->u.l.f; /* go if false */
+ exitlist = &v->u.l.t; /* exit if true */
+ }
+ else {
+ golist = &v->u.l.t; /* go if true */
+ exitlist = &v->u.l.f; /* exit if false */
}
discharge1(fs, v);
- previous = &fs->f->code[fs->pc-1];
- LUA_ASSERT(L, GET_OPCODE(*previous) != OP_SETLINE, "bad place to set line");
+ prevpos = fs->pc-1;
+ previous = &fs->f->code[prevpos];
+ LUA_ASSERT(L, *previous==previous_instruction(fs), "no jump allowed here");
+ LUA_ASSERT(L, GET_OPCODE(*previous) != OP_SETLINE, "no setline allowed here");
if (!ISJUMP(GET_OPCODE(*previous)))
- luaK_code1(fs, jump, NO_JUMP);
- else if (invert)
- SET_OPCODE(*previous, invertjump(GET_OPCODE(*previous)));
- luaK_concat(fs, exitlist, fs->pc-1); /* insert last jump in `exitlist' */
+ prevpos = luaK_code1(fs, jump, NO_JUMP);
+ else { /* last instruction is already a jump */
+ if (invert)
+ SET_OPCODE(*previous, invertjump(GET_OPCODE(*previous)));
+ }
+ luaK_concat(fs, exitlist, prevpos); /* insert last jump in `exitlist' */
luaK_patchlist(fs, *golist, luaK_getlabel(fs));
*golist = NO_JUMP;
}
@@ -292,7 +301,7 @@ void luaK_goiftrue (FuncState *fs, expdesc *v, int keepvalue) {
}
-void luaK_goiffalse (FuncState *fs, expdesc *v, int keepvalue) {
+static void luaK_goiffalse (FuncState *fs, expdesc *v, int keepvalue) {
luaK_testgo(fs, v, 0, keepvalue ? OP_JMPONT : OP_JMPT);
}
@@ -319,8 +328,8 @@ void luaK_tostack (LexState *ls, expdesc *v, int onlyone) {
int j = NO_JUMP; /* eventual jump over values */
int p_nil = NO_JUMP; /* position of an eventual PUSHNIL */
int p_1 = NO_JUMP; /* position of an eventual PUSHINT */
- if (ISJUMP(previous) || need_value(fs, v->u.l.f, OP_JMPONF) ||
- need_value(fs, v->u.l.t, OP_JMPONT)) {
+ if (ISJUMP(previous) || need_value(fs, v->u.l.f, OP_JMPONF)
+ || need_value(fs, v->u.l.t, OP_JMPONT)) {
/* expression needs values */
if (ISJUMP(previous))
luaK_concat(fs, &v->u.l.t, fs->pc-1); /* put `previous' in t. list */
@@ -425,34 +434,33 @@ int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
int delta = luaK_opproperties[o].delta;
int optm = 0; /* 1 when there is an optimization */
switch (o) {
-
- case OP_CLOSURE:
+ case OP_CLOSURE: {
delta = -arg2+1;
break;
-
- case OP_SETTABLE:
+ }
+ case OP_SETTABLE: {
delta = -arg2;
break;
-
- case OP_SETLIST:
+ }
+ case OP_SETLIST: {
if (arg2 == 0) return NO_JUMP; /* nothing to do */
delta = -arg2;
break;
-
- case OP_SETMAP:
+ }
+ case OP_SETMAP: {
if (arg1 == 0) return NO_JUMP; /* nothing to do */
delta = -2*arg1;
break;
-
- case OP_RETURN:
+ }
+ case OP_RETURN: {
if (GET_OPCODE(i) == OP_CALL && GETARG_B(i) == MULT_RET) {
SET_OPCODE(i, OP_TAILCALL);
SETARG_B(i, arg1);
optm = 1;
}
break;
-
- case OP_PUSHNIL:
+ }
+ case OP_PUSHNIL: {
if (arg1 == 0) return NO_JUMP; /* nothing to do */
delta = arg1;
switch(GET_OPCODE(i)) {
@@ -460,8 +468,8 @@ int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
default: break;
}
break;
-
- case OP_POP:
+ }
+ case OP_POP: {
if (arg1 == 0) return NO_JUMP; /* nothing to do */
delta = -arg1;
switch(GET_OPCODE(i)) {
@@ -469,8 +477,8 @@ int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
default: break;
}
break;
-
- case OP_GETTABLE:
+ }
+ case OP_GETTABLE: {
switch(GET_OPCODE(i)) {
case OP_PUSHSTRING: /* `t.x' */
SET_OPCODE(i, OP_GETDOTTED);
@@ -483,15 +491,15 @@ int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
default: break;
}
break;
-
- case OP_ADD:
+ }
+ case OP_ADD: {
switch(GET_OPCODE(i)) {
case OP_PUSHINT: SET_OPCODE(i, OP_ADDI); optm = 1; break; /* `a+k' */
default: break;
}
break;
-
- case OP_SUB:
+ }
+ case OP_SUB: {
switch(GET_OPCODE(i)) {
case OP_PUSHINT: /* `a-k' */
i = CREATE_S(OP_ADDI, -GETARG_S(i));
@@ -500,8 +508,8 @@ int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
default: break;
}
break;
-
- case OP_CONCAT:
+ }
+ case OP_CONCAT: {
delta = -arg1+1;
switch(GET_OPCODE(i)) {
case OP_CONCAT: /* `a..b..c' */
@@ -511,8 +519,8 @@ int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
default: break;
}
break;
-
- case OP_MINUS:
+ }
+ case OP_MINUS: {
switch(GET_OPCODE(i)) {
case OP_PUSHINT: /* `-k' */
SETARG_S(i, -GETARG_S(i));
@@ -525,50 +533,91 @@ int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
default: break;
}
break;
-
- case OP_JMPNE:
+ }
+ case OP_JMPNE: {
if (i == CREATE_U(OP_PUSHNIL, 1)) { /* `a~=nil' */
i = CREATE_S(OP_JMPT, NO_JUMP);
optm = 1;
}
break;
-
- case OP_JMPEQ:
+ }
+ case OP_JMPEQ: {
if (i == CREATE_U(OP_PUSHNIL, 1)) { /* `a==nil' */
i = CREATE_0(OP_NOT);
delta = -1; /* just undo effect of previous PUSHNIL */
optm = 1;
}
break;
-
+ }
case OP_JMPT:
+ case OP_JMPONT: {
+ switch (GET_OPCODE(i)) {
+ case OP_NOT: {
+ i = CREATE_S(OP_JMPF, NO_JUMP);
+ optm = 1;
+ break;
+ }
+ case OP_PUSHINT: {
+ if (o == OP_JMPT) { /* JMPONT must keep original integer value */
+ i = CREATE_S(OP_JMP, NO_JUMP);
+ optm = 1;
+ }
+ break;
+ }
+ case OP_PUSHNIL: {
+ if (GETARG_U(i) == 1) {
+ fs->pc--; /* erase previous instruction */
+ luaK_deltastack(fs, -1); /* correct stack */
+ return NO_JUMP;
+ }
+ break;
+ }
+ default: break;
+ }
+ break;
+ }
case OP_JMPF:
- case OP_JMPONT:
- case OP_JMPONF:
+ case OP_JMPONF: {
switch (GET_OPCODE(i)) {
- case OP_NOT: i = CREATE_S(invertjump(o), NO_JUMP); optm = 1; break;
+ case OP_NOT: {
+ i = CREATE_S(OP_JMPT, NO_JUMP);
+ optm = 1;
+ break;
+ }
+ case OP_PUSHINT: { /* `while 1 do ...' */
+ fs->pc--; /* erase previous instruction */
+ luaK_deltastack(fs, -1); /* correct stack */
+ return NO_JUMP;
+ }
+ case OP_PUSHNIL: { /* `repeat ... until nil' */
+ if (GETARG_U(i) == 1) {
+ i = CREATE_S(OP_JMP, NO_JUMP);
+ optm = 1;
+ }
+ break;
+ }
default: break;
}
break;
-
+ }
case OP_GETDOTTED:
case OP_GETINDEXED:
case OP_TAILCALL:
- case OP_ADDI:
+ case OP_ADDI: {
LUA_INTERNALERROR(L, "instruction used only for optimizations");
break;
-
- default:
+ }
+ default: {
LUA_ASSERT(L, delta != VD, "invalid delta");
break;
-
+ }
}
luaK_deltastack(fs, delta);
if (optm) { /* optimize: put instruction in place of last one */
fs->f->code[fs->pc-1] = i; /* change previous instruction */
return fs->pc-1; /* do not generate new instruction */
}
- /* build new instruction */
+ /* else build new instruction */
switch ((enum Mode)luaK_opproperties[o].mode) {
case iO: i = CREATE_0(o); break;
case iU: i = CREATE_U(o, arg1); break;
diff --git a/lcode.h b/lcode.h
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.h,v 1.12 2000/04/12 18:47:03 roberto Exp roberto $
+** $Id: lcode.h,v 1.13 2000/05/22 18:44:46 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -36,7 +36,6 @@ int luaK_jump (FuncState *fs);
void luaK_patchlist (FuncState *fs, int list, int target);
void luaK_concat (FuncState *fs, int *l1, int l2);
void luaK_goiftrue (FuncState *fs, expdesc *v, int keepvalue);
-void luaK_goiffalse (FuncState *fs, expdesc *v, int keepvalue);
int luaK_getlabel (FuncState *fs);
void luaK_deltastack (FuncState *fs, int delta);
void luaK_kstr (LexState *ls, int c);
