commit 2dadc8182282afa4b1fe6e6287704a54cd8e5123
parent b487975344ee90c0410e79e1af08461bdbc0f3da
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 10 May 2002 16:21:49 -0300
cleaner implementation of code generation for jumps
Diffstat:
4 files changed, 46 insertions(+), 53 deletions(-)
diff --git a/lcode.c b/lcode.c
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.c,v 1.100 2002/05/09 14:14:34 roberto Exp roberto $
+** $Id: lcode.c,v 1.101 2002/05/10 17:02:32 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -39,58 +39,48 @@ 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? */
- luaK_concat(fs, &j, fs->jlt); /* keep them on hold */
- fs->jlt = NO_JUMP;
- }
+ int jpc = fs->jpc; /* save list of jumps to here */
+ int j;
+ fs->jpc = NO_JUMP;
+ j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
+ luaK_concat(fs, &j, jpc); /* keep them on hold */
return j;
}
static int luaK_condjump (FuncState *fs, OpCode op, int A, int B, int C) {
luaK_codeABC(fs, op, A, B, C);
- return luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
+ return luaK_jump(fs);
}
static void luaK_fixjump (FuncState *fs, int pc, int dest) {
Instruction *jmp = &fs->f->code[pc];
- if (dest == NO_JUMP)
- SETARG_sBx(*jmp, NO_JUMP); /* point to itself to represent end of list */
- else { /* jump is relative to position following jump instruction */
- int offset = dest-(pc+1);
- if (abs(offset) > MAXARG_sBx)
- luaX_syntaxerror(fs->ls, "control structure too long");
- SETARG_sBx(*jmp, offset);
- }
+ int offset = dest-(pc+1);
+ lua_assert(dest != NO_JUMP);
+ if (abs(offset) > MAXARG_sBx)
+ luaX_syntaxerror(fs->ls, "control structure too long");
+ SETARG_sBx(*jmp, offset);
}
/*
** returns current `pc' and marks it as a jump target (to avoid wrong
** optimizations with consecutive instructions not in the same basic block).
-** discharge list of jumps to last target.
*/
int luaK_getlabel (FuncState *fs) {
- if (fs->pc != fs->lasttarget) {
- int lasttarget = fs->lasttarget;
- fs->lasttarget = fs->pc;
- luaK_patchlist(fs, fs->jlt, lasttarget); /* discharge old list `jlt' */
- fs->jlt = NO_JUMP; /* nobody jumps to this new label (yet) */
- }
+ fs->lasttarget = fs->pc;
return fs->pc;
}
+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 */
@@ -155,20 +145,20 @@ static void luaK_patchlistaux (FuncState *fs, int list,
void luaK_patchlist (FuncState *fs, int list, int target) {
- if (target == fs->lasttarget) /* same target that list `jlt'? */
- luaK_concat(fs, &fs->jlt, list); /* delay fixing */
- else
- luaK_patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
+ lua_assert(target <= fs->pc);
+ luaK_patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
}
void luaK_patchtohere (FuncState *fs, int list) {
- luaK_patchlist(fs, list, luaK_getlabel(fs));
+ luaK_getlabel(fs);
+ luaK_concat(fs, &fs->jpc, list);
}
void luaK_concat (FuncState *fs, int *l1, int l2) {
- if (*l1 == NO_JUMP)
+ if (l2 == NO_JUMP) return;
+ else if (*l1 == NO_JUMP)
*l1 = l2;
else {
int list = *l1;
@@ -508,7 +498,7 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) {
break;
}
case VFALSE: {
- pc = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); /* always jump */
+ pc = luaK_jump(fs); /* always jump */
break;
}
case VJMP: {
@@ -534,7 +524,7 @@ void luaK_goiffalse (FuncState *fs, expdesc *e) {
break;
}
case VTRUE: {
- pc = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); /* always jump */
+ pc = luaK_jump(fs); /* always jump */
break;
}
case VJMP: {
@@ -737,6 +727,7 @@ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
int luaK_code (FuncState *fs, Instruction i, int line) {
Proto *f = fs->f;
int oldsize = f->sizecode;
+ luaK_dischargejpc(fs); /* `pc' will change */
/* put new instruction in code array */
luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
MAX_INT, "code size overflow");
diff --git a/lcode.h b/lcode.h
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.h,v 1.33 2002/05/07 17:36:56 roberto Exp roberto $
+** $Id: lcode.h,v 1.34 2002/05/10 17:02:32 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -55,12 +55,12 @@ 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);
+void luaK_dischargejpc (FuncState *fs);
void luaK_patchlist (FuncState *fs, int list, int target);
void luaK_patchtohere (FuncState *fs, int list);
void luaK_concat (FuncState *fs, int *l1, int l2);
diff --git a/lparser.c b/lparser.c
@@ -1,5 +1,5 @@
/*
-** $Id: lparser.c,v 1.179 2002/05/07 17:36:56 roberto Exp roberto $
+** $Id: lparser.c,v 1.180 2002/05/10 17:02:32 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -367,7 +367,7 @@ static void open_func (LexState *ls, FuncState *fs) {
ls->fs = fs;
fs->pc = 0;
fs->lasttarget = 0;
- fs->jlt = NO_JUMP;
+ fs->jpc = NO_JUMP;
fs->freereg = 0;
fs->nk = 0;
fs->h = luaH_new(ls->L, 0, 0);
@@ -391,7 +391,6 @@ static void close_func (LexState *ls) {
Proto *f = fs->f;
removevars(ls, 0);
luaK_codeABC(fs, OP_RETURN, 0, 1, 0); /* final return */
- luaK_getlabel(fs); /* close eventual list of pending jumps */
lua_assert(G(L)->roottable == fs->h);
G(L)->roottable = fs->h->next;
luaH_free(L, fs->h);
@@ -977,30 +976,33 @@ static void whilestat (LexState *ls, int line) {
int i;
int sizeexp;
FuncState *fs = ls->fs;
- int while_init = luaK_getlabel(fs);
+ int whileinit, blockinit, expinit;
expdesc v;
BlockCnt bl;
next(ls);
+ whileinit = luaK_jump(fs);
+ expinit = luaK_getlabel(fs);
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;
+ luaK_dischargejpc(fs);
+ sizeexp = fs->pc - expinit;
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);
+ codeexp[i] = fs->f->code[expinit + i];
+ fs->pc = expinit; /* remove `exp' code */
enterblock(fs, &bl, 1);
check(ls, TK_DO);
+ blockinit = luaK_getlabel(fs);
block(ls);
- luaK_patchtohere(fs, while_init); /* initial jump jumps to here */
- luaK_moveexp(&v, fs->pc - while_init); /* correct pointers */
+ luaK_patchtohere(fs, whileinit); /* initial jump jumps to here */
+ if (v.t != NO_JUMP) v.t += fs->pc - expinit;
+ if (v.f != NO_JUMP) v.f += fs->pc - expinit;
for (i=0; i<sizeexp; i++)
luaK_code(fs, codeexp[i], lineexp);
- luaK_patchlist(fs, v.t, while_init+1);
+ luaK_patchlist(fs, v.t, blockinit);
luaK_patchtohere(fs, v.f);
check_match(ls, TK_END, TK_WHILE, line);
leaveblock(fs);
diff --git a/lparser.h b/lparser.h
@@ -1,5 +1,5 @@
/*
-** $Id: lparser.h,v 1.41 2002/03/25 17:47:14 roberto Exp roberto $
+** $Id: lparser.h,v 1.42 2002/05/09 18:00:38 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -63,7 +63,7 @@ typedef struct FuncState {
struct BlockCnt *bl; /* chain of current blocks */
int pc; /* next position to code (equivalent to `ncode') */
int lasttarget; /* `pc' of last `jump target' */
- int jlt; /* list of jumps to `lasttarget' */
+ int jpc; /* list of jumps to `pc' */
int freereg; /* first free register */
int defaultglob; /* where to look for non-declared globals */
int nk; /* number of elements in `k' */
