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implementation of BREAK

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This commit is contained in:
Roberto Ierusalimschy
2000-04-05 14:51:58 -03:00
parent 9f734094f9
commit 22329e4cdf
6 changed files with 168 additions and 117 deletions
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92
lcode.c
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lcode.c,v 1.18 2000/03/24 17:26:08 roberto Exp roberto $ ** $Id: lcode.c,v 1.19 2000/04/04 20:48:44 roberto Exp roberto $
** Code generator for Lua ** Code generator for Lua
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -23,6 +23,18 @@ void luaK_error (LexState *ls, const char *msg) {
luaX_error(ls, msg, ls->token); luaX_error(ls, msg, ls->token);
} }
/*
** Returns the the previous instruction, for optimizations.
** If there is a jump target between this and the current instruction,
** returns a dummy instruction to avoid wrong optimizations.
*/
static Instruction previous_instruction (FuncState *fs) {
if (fs->pc > fs->lasttarget) /* no jumps to current position? */
return fs->f->code[fs->pc-1]; /* returns previous instruction */
else
return CREATE_0(OP_END); /* no optimizations after an `END' */
}
int luaK_code (FuncState *fs, Instruction i, int delta) { int luaK_code (FuncState *fs, Instruction i, int delta) {
luaK_deltastack(fs, delta); luaK_deltastack(fs, delta);
@@ -48,19 +60,6 @@ int luaK_AB(FuncState *fs, OpCode o, int a, int b, int d) {
} }
/*
** Returns the the previous instruction, for optimizations.
** If there is a jump target between this and the current instruction,
** returns a dummy instruction to avoid wrong optimizations.
*/
static Instruction previous_instruction (FuncState *fs) {
if (fs->pc > fs->lasttarget) /* no jumps to current position? */
return fs->f->code[fs->pc-1]; /* returns previous instruction */
else
return CREATE_0(OP_END); /* no optimizations after an `END' */
}
static Instruction prepare (FuncState *fs, Instruction i, int delta) { static Instruction prepare (FuncState *fs, Instruction i, int delta) {
Instruction previous = previous_instruction(fs); Instruction previous = previous_instruction(fs);
luaK_code(fs, i, delta); luaK_code(fs, i, delta);
@@ -154,7 +153,7 @@ static void luaK_setlocal (FuncState *fs, int l) {
static void luaK_eq (FuncState *fs) { static void luaK_eq (FuncState *fs) {
/* PUSHNIL 1; JMPEQ -> NOT (a==nil) */ /* PUSHNIL 1; JMPEQ -> NOT (a==nil) */
Instruction previous = prepare(fs, CREATE_S(OP_JMPEQ, 0), -2); Instruction previous = prepare(fs, CREATE_S(OP_JMPEQ, NO_JUMP), -2);
if (previous == CREATE_U(OP_PUSHNIL, 1)) { if (previous == CREATE_U(OP_PUSHNIL, 1)) {
setprevious(fs, CREATE_0(OP_NOT)); setprevious(fs, CREATE_0(OP_NOT));
luaK_deltastack(fs, 1); /* undo delta from `prepare' */ luaK_deltastack(fs, 1); /* undo delta from `prepare' */
@@ -164,13 +163,18 @@ static void luaK_eq (FuncState *fs) {
static void luaK_neq (FuncState *fs) { static void luaK_neq (FuncState *fs) {
/* PUSHNIL 1; JMPNEQ -> JMPT (a~=nil) */ /* PUSHNIL 1; JMPNEQ -> JMPT (a~=nil) */
Instruction previous = prepare(fs, CREATE_S(OP_JMPNEQ, 0), -2); Instruction previous = prepare(fs, CREATE_S(OP_JMPNEQ, NO_JUMP), -2);
if (previous == CREATE_U(OP_PUSHNIL, 1)) { if (previous == CREATE_U(OP_PUSHNIL, 1)) {
setprevious(fs, CREATE_S(OP_JMPT, 0)); setprevious(fs, CREATE_S(OP_JMPT, NO_JUMP));
} }
} }
int luaK_jump (FuncState *fs) {
return luaK_S(fs, OP_JMP, NO_JUMP, 0);
}
void luaK_retcode (FuncState *fs, int nlocals, int nexps) { void luaK_retcode (FuncState *fs, int nlocals, int nexps) {
Instruction previous = prepare(fs, CREATE_U(OP_RETURN, nlocals), 0); Instruction previous = prepare(fs, CREATE_U(OP_RETURN, nlocals), 0);
if (nexps > 0 && GET_OPCODE(previous) == OP_CALL) { if (nexps > 0 && GET_OPCODE(previous) == OP_CALL) {
@@ -192,12 +196,13 @@ static void luaK_pushnil (FuncState *fs, int n) {
} }
void luaK_fixjump (FuncState *fs, int pc, int dest) { static void luaK_fixjump (FuncState *fs, int pc, int dest) {
Instruction *jmp = &fs->f->code[pc]; Instruction *jmp = &fs->f->code[pc];
if (dest == NO_JUMP) if (dest == NO_JUMP)
SETARG_S(*jmp, 0); /* absolute value to represent end of list */ SETARG_S(*jmp, NO_JUMP); /* point to itself to represent end of list */
else { /* jump is relative to position following jump instruction */ else { /* jump is relative to position following jump instruction */
int offset = dest-(pc+1); int offset = dest-(pc+1);
LUA_ASSERT(L, offset != NO_JUMP, "cannot link to itself");
if (abs(offset) > MAXARG_S) if (abs(offset) > MAXARG_S)
luaK_error(fs->ls, "control structure too long"); luaK_error(fs->ls, "control structure too long");
SETARG_S(*jmp, offset); SETARG_S(*jmp, offset);
@@ -207,7 +212,7 @@ void luaK_fixjump (FuncState *fs, int pc, int dest) {
static int luaK_getjump (FuncState *fs, int pc) { static int luaK_getjump (FuncState *fs, int pc) {
int offset = GETARG_S(fs->f->code[pc]); int offset = GETARG_S(fs->f->code[pc]);
if (offset == 0) if (offset == NO_JUMP) /* point to itself represents end of list */
return NO_JUMP; /* end of list */ return NO_JUMP; /* end of list */
else else
return (pc+1)+offset; /* turn offset into absolute position */ return (pc+1)+offset; /* turn offset into absolute position */
@@ -225,11 +230,11 @@ int luaK_getlabel (FuncState *fs) {
void luaK_deltastack (FuncState *fs, int delta) { void luaK_deltastack (FuncState *fs, int delta) {
fs->stacksize += delta; fs->stacklevel += delta;
if (delta > 0 && fs->stacksize > fs->f->maxstacksize) { if (delta > 0 && fs->stacklevel > fs->f->maxstacksize) {
if (fs->stacksize > MAXSTACK) if (fs->stacklevel > MAXSTACK)
luaK_error(fs->ls, "function or expression too complex"); luaK_error(fs->ls, "function or expression too complex");
fs->f->maxstacksize = fs->stacksize; fs->f->maxstacksize = fs->stacklevel;
} }
} }
@@ -357,29 +362,16 @@ static OpCode invertjump (OpCode op) {
} }
static void luaK_jump (FuncState *fs, OpCode jump) { static void luaK_condjump (FuncState *fs, OpCode jump) {
Instruction previous = prepare(fs, CREATE_S(jump, 0), -1); Instruction previous = prepare(fs, CREATE_S(jump, NO_JUMP), -1);
switch (GET_OPCODE(previous)) { switch (GET_OPCODE(previous)) {
case OP_NOT: previous = CREATE_S(invertjump(jump), 0); break; case OP_NOT: previous = CREATE_S(invertjump(jump), NO_JUMP); break;
case OP_PUSHNIL: /* optimize `repeat until nil' */
if (GETARG_U(previous) == 1 && jump == OP_JMPF) {
previous = CREATE_S(OP_JMP, 0);
break;
}
else return; /* do not set previous */
default: return; default: return;
} }
setprevious(fs, previous); setprevious(fs, previous);
} }
static void insert_last (FuncState *fs, int *list) {
int first = *list;
*list = fs->pc-1; /* insert last instruction in the list */
luaK_fixjump(fs, *list, first);
}
static void luaK_patchlistaux (FuncState *fs, int list, int target, static void luaK_patchlistaux (FuncState *fs, int list, int target,
OpCode special, int special_target) { OpCode special, int special_target) {
Instruction *code = fs->f->code; Instruction *code = fs->f->code;
@@ -414,7 +406,7 @@ static int need_value (FuncState *fs, int list, OpCode hasvalue) {
} }
static void concatlists (FuncState *fs, int *l1, int l2) { void luaK_concat (FuncState *fs, int *l1, int l2) {
if (*l1 == NO_JUMP) if (*l1 == NO_JUMP)
*l1 = l2; *l1 = l2;
else { else {
@@ -446,8 +438,8 @@ static void luaK_testgo (FuncState *fs, expdesc *v, int invert, OpCode jump) {
SET_OPCODE(*previous, invertjump(GET_OPCODE(*previous))); SET_OPCODE(*previous, invertjump(GET_OPCODE(*previous)));
} }
else else
luaK_jump(fs, jump); luaK_condjump(fs, jump);
insert_last(fs, exitlist); luaK_concat(fs, exitlist, fs->pc-1); /* insert last jump in `exitlist' */
luaK_patchlist(fs, *golist, luaK_getlabel(fs)); luaK_patchlist(fs, *golist, luaK_getlabel(fs));
*golist = NO_JUMP; *golist = NO_JUMP;
} }
@@ -478,7 +470,7 @@ void luaK_tostack (LexState *ls, expdesc *v, int onlyone) {
int p_1 = 0; /* position of an eventual PUSHINT */ int p_1 = 0; /* position of an eventual PUSHINT */
int final; /* position after whole expression */ int final; /* position after whole expression */
if (ISJUMP(previous)) { if (ISJUMP(previous)) {
insert_last(fs, &v->u.l.t); /* put `previous' in true list */ luaK_concat(fs, &v->u.l.t, fs->pc-1); /* put `previous' in true list */
p_nil = luaK_0(fs, OP_PUSHNILJMP, 0); p_nil = luaK_0(fs, OP_PUSHNILJMP, 0);
p_1 = luaK_S(fs, OP_PUSHINT, 1, 1); p_1 = luaK_S(fs, OP_PUSHINT, 1, 1);
} }
@@ -544,13 +536,13 @@ void luaK_posfix (LexState *ls, int op, expdesc *v1, expdesc *v2) {
LUA_ASSERT(ls->L, v1->u.l.t == NO_JUMP, "list must be closed"); LUA_ASSERT(ls->L, v1->u.l.t == NO_JUMP, "list must be closed");
discharge1(fs, v2); discharge1(fs, v2);
v1->u.l.t = v2->u.l.t; v1->u.l.t = v2->u.l.t;
concatlists(fs, &v1->u.l.f, v2->u.l.f); luaK_concat(fs, &v1->u.l.f, v2->u.l.f);
} }
else if (op == TK_OR) { else if (op == TK_OR) {
LUA_ASSERT(ls->L, v1->u.l.f == NO_JUMP, "list must be closed"); LUA_ASSERT(ls->L, v1->u.l.f == NO_JUMP, "list must be closed");
discharge1(fs, v2); discharge1(fs, v2);
v1->u.l.f = v2->u.l.f; v1->u.l.f = v2->u.l.f;
concatlists(fs, &v1->u.l.t, v2->u.l.t); luaK_concat(fs, &v1->u.l.t, v2->u.l.t);
} }
else { else {
luaK_tostack(ls, v2, 1); /* `v2' must be a value */ luaK_tostack(ls, v2, 1); /* `v2' must be a value */
@@ -563,10 +555,10 @@ void luaK_posfix (LexState *ls, int op, expdesc *v1, expdesc *v2) {
case TK_CONC: luaK_conc(fs); break; case TK_CONC: luaK_conc(fs); break;
case TK_EQ: luaK_eq(fs); break; case TK_EQ: luaK_eq(fs); break;
case TK_NE: luaK_neq(fs); break; case TK_NE: luaK_neq(fs); break;
case '>': luaK_S(fs, OP_JMPGT, 0, -2); break; case '>': luaK_S(fs, OP_JMPGT, NO_JUMP, -2); break;
case '<': luaK_S(fs, OP_JMPLT, 0, -2); break; case '<': luaK_S(fs, OP_JMPLT, NO_JUMP, -2); break;
case TK_GE: luaK_S(fs, OP_JMPGE, 0, -2); break; case TK_GE: luaK_S(fs, OP_JMPGE, NO_JUMP, -2); break;
case TK_LE: luaK_S(fs, OP_JMPLE, 0, -2); break; case TK_LE: luaK_S(fs, OP_JMPLE, NO_JUMP, -2); break;
} }
} }
} }

8
lcode.h
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lcode.h,v 1.8 2000/03/15 20:50:33 roberto Exp roberto $ ** $Id: lcode.h,v 1.9 2000/03/17 13:09:46 roberto Exp roberto $
** Code generator for Lua ** Code generator for Lua
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -13,6 +13,9 @@
#include "lparser.h" #include "lparser.h"
#define NO_JUMP (-1) /* marks end of patch list */
void luaK_error (LexState *ls, const char *msg); void luaK_error (LexState *ls, const char *msg);
int luaK_0(FuncState *fs, OpCode o, int d); int luaK_0(FuncState *fs, OpCode o, int d);
int luaK_U(FuncState *fs, OpCode o, int u, int d); int luaK_U(FuncState *fs, OpCode o, int u, int d);
@@ -20,8 +23,9 @@ int luaK_S(FuncState *fs, OpCode o, int s, int d);
int luaK_AB(FuncState *fs, OpCode o, int a, int b, int d); int luaK_AB(FuncState *fs, OpCode o, int a, int b, int d);
int luaK_code (FuncState *fs, Instruction i, int delta); int luaK_code (FuncState *fs, Instruction i, int delta);
void luaK_retcode (FuncState *fs, int nlocals, int nexps); void luaK_retcode (FuncState *fs, int nlocals, int nexps);
void luaK_fixjump (FuncState *fs, int pc, int dest); int luaK_jump (FuncState *fs);
void luaK_patchlist (FuncState *fs, int list, int target); 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_goiftrue (FuncState *fs, expdesc *v, int keepvalue);
void luaK_goiffalse (FuncState *fs, expdesc *v, int keepvalue); void luaK_goiffalse (FuncState *fs, expdesc *v, int keepvalue);
int luaK_getlabel (FuncState *fs); int luaK_getlabel (FuncState *fs);

5
llex.c
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: llex.c,v 1.53 2000/03/10 18:37:44 roberto Exp roberto $ ** $Id: llex.c,v 1.54 2000/03/24 17:26:08 roberto Exp roberto $
** Lexical Analyzer ** Lexical Analyzer
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -31,7 +31,8 @@
/* ORDER RESERVED */ /* ORDER RESERVED */
static const char *const token2string [] = {"and", "do", "else", "elseif", "end", static const char *const token2string [] = {
"and", "break", "do", "else", "elseif", "end",
"function", "if", "local", "nil", "not", "or", "repeat", "return", "then", "function", "if", "local", "nil", "not", "or", "repeat", "return", "then",
"until", "while", "", "..", "...", "==", ">=", "<=", "~=", "", "", "<eof>"}; "until", "while", "", "..", "...", "==", ">=", "<=", "~=", "", "", "<eof>"};

4
llex.h
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: llex.h,v 1.20 2000/03/10 18:37:44 roberto Exp roberto $ ** $Id: llex.h,v 1.21 2000/03/24 17:26:08 roberto Exp roberto $
** Lexical Analyzer ** Lexical Analyzer
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -23,7 +23,7 @@
*/ */
enum RESERVED { enum RESERVED {
/* terminal symbols denoted by reserved words */ /* terminal symbols denoted by reserved words */
TK_AND = FIRST_RESERVED, TK_AND = FIRST_RESERVED, TK_BREAK,
TK_DO, TK_ELSE, TK_ELSEIF, TK_END, TK_FUNCTION, TK_IF, TK_LOCAL, TK_DO, TK_ELSE, TK_ELSEIF, TK_END, TK_FUNCTION, TK_IF, TK_LOCAL,
TK_NIL, TK_NOT, TK_OR, TK_REPEAT, TK_RETURN, TK_THEN, TK_UNTIL, TK_WHILE, TK_NIL, TK_NOT, TK_OR, TK_REPEAT, TK_RETURN, TK_THEN, TK_UNTIL, TK_WHILE,
/* other terminal symbols */ /* other terminal symbols */

169
lparser.c
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lparser.c,v 1.74 2000/03/29 20:19:20 roberto Exp roberto $ ** $Id: lparser.c,v 1.75 2000/04/03 13:44:55 roberto Exp roberto $
** LL(1) Parser and code generator for Lua ** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -28,10 +28,17 @@
** it is a list constructor (k = 0) or a record constructor (k = 1) ** it is a list constructor (k = 0) or a record constructor (k = 1)
** or empty (k = ';' or '}') ** or empty (k = ';' or '}')
*/ */
typedef struct constdesc { typedef struct Constdesc {
int n; int n;
int k; int k;
} constdesc; } Constdesc;
typedef struct Breaklabel {
struct Breaklabel *previous; /* chain */
int breaklist;
int stacklevel;
} Breaklabel;
@@ -311,6 +318,21 @@ static int getvarname (LexState *ls, expdesc *var) {
} }
static void enterbreak (FuncState *fs, Breaklabel *bl) {
bl->stacklevel = fs->stacklevel;
bl->breaklist = NO_JUMP;
bl->previous = fs->bl;
fs->bl = bl;
}
static void leavebreak (FuncState *fs, Breaklabel *bl) {
fs->bl = bl->previous;
LUA_ASSERT(fs->L, bl->stacklevel == fs->stacklevel, "wrong levels");
luaK_patchlist(fs, bl->breaklist, luaK_getlabel(fs));
}
static void func_onstack (LexState *ls, FuncState *func) { static void func_onstack (LexState *ls, FuncState *func) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
Proto *f = fs->f; Proto *f = fs->f;
@@ -332,10 +354,11 @@ static void init_state (LexState *ls, FuncState *fs, TString *source) {
fs->ls = ls; fs->ls = ls;
fs->L = ls->L; fs->L = ls->L;
ls->fs = fs; ls->fs = fs;
fs->stacksize = 0; fs->stacklevel = 0;
fs->nlocalvar = 0; fs->nlocalvar = 0;
fs->nupvalues = 0; fs->nupvalues = 0;
fs->lastsetline = 0; fs->lastsetline = 0;
fs->bl = NULL;
fs->f = f; fs->f = f;
f->source = source; f->source = source;
fs->pc = 0; fs->pc = 0;
@@ -362,6 +385,7 @@ static void close_func (LexState *ls) {
luaM_reallocvector(L, f->locvars, fs->nvars, LocVar); luaM_reallocvector(L, f->locvars, fs->nvars, LocVar);
} }
ls->fs = fs->prev; ls->fs = fs->prev;
LUA_ASSERT(L, fs->bl == NULL, "wrong list end");
} }
@@ -375,6 +399,7 @@ Proto *luaY_parser (lua_State *L, ZIO *z) {
if (lexstate.token != TK_EOS) if (lexstate.token != TK_EOS)
luaK_error(&lexstate, "<eof> expected"); luaK_error(&lexstate, "<eof> expected");
close_func(&lexstate); close_func(&lexstate);
LUA_ASSERT(L, funcstate.prev == NULL, "wrong list end");
return funcstate.f; return funcstate.f;
} }
@@ -416,7 +441,7 @@ static int explist (LexState *ls) {
static void funcargs (LexState *ls, int slf) { static void funcargs (LexState *ls, int slf) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
int slevel = fs->stacksize - slf - 1; /* where is func in the stack */ int slevel = fs->stacklevel - slf - 1; /* where is func in the stack */
switch (ls->token) { switch (ls->token) {
case '(': { /* funcargs -> '(' explist ')' */ case '(': { /* funcargs -> '(' explist ')' */
int line = ls->linenumber; int line = ls->linenumber;
@@ -444,7 +469,7 @@ static void funcargs (LexState *ls, int slf) {
luaK_error(ls, "function arguments expected"); luaK_error(ls, "function arguments expected");
break; break;
} }
fs->stacksize = slevel; /* call will remove function and arguments */ fs->stacklevel = slevel; /* call will remove function and arguments */
luaK_AB(fs, OP_CALL, slevel, MULT_RET, 0); luaK_AB(fs, OP_CALL, slevel, MULT_RET, 0);
} }
@@ -581,7 +606,7 @@ static int listfields (LexState *ls) {
static void constructor_part (LexState *ls, constdesc *cd) { static void constructor_part (LexState *ls, Constdesc *cd) {
switch (ls->token) { switch (ls->token) {
case ';': case '}': /* constructor_part -> empty */ case ';': case '}': /* constructor_part -> empty */
cd->n = 0; cd->n = 0;
@@ -627,12 +652,12 @@ static void constructor (LexState *ls) {
int line = ls->linenumber; int line = ls->linenumber;
int pc = luaK_U(fs, OP_CREATETABLE, 0, 1); int pc = luaK_U(fs, OP_CREATETABLE, 0, 1);
int nelems; int nelems;
constdesc cd; Constdesc cd;
check(ls, '{'); check(ls, '{');
constructor_part(ls, &cd); constructor_part(ls, &cd);
nelems = cd.n; nelems = cd.n;
if (ls->token == ';') { if (ls->token == ';') {
constdesc other_cd; Constdesc other_cd;
next(ls); next(ls);
constructor_part(ls, &other_cd); constructor_part(ls, &other_cd);
if (cd.k == other_cd.k) /* repeated parts? */ if (cd.k == other_cd.k) /* repeated parts? */
@@ -825,14 +850,17 @@ static void whilestat (LexState *ls, int line) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
int while_init = luaK_getlabel(fs); int while_init = luaK_getlabel(fs);
expdesc v; expdesc v;
Breaklabel bl;
enterbreak(fs, &bl);
setline_and_next(ls); /* trace WHILE when looping */ setline_and_next(ls); /* trace WHILE when looping */
expr(ls, &v); /* read condition */ expr(ls, &v); /* read condition */
luaK_goiftrue(fs, &v, 0); luaK_goiftrue(fs, &v, 0);
check(ls, TK_DO); check(ls, TK_DO);
block(ls); block(ls);
luaK_fixjump(fs, luaK_S(fs, OP_JMP, 0, 0), while_init); luaK_patchlist(fs, luaK_jump(fs), while_init);
luaK_patchlist(fs, v.u.l.f, luaK_getlabel(fs)); luaK_patchlist(fs, v.u.l.f, luaK_getlabel(fs));
check_END(ls, TK_WHILE, line); check_END(ls, TK_WHILE, line);
leavebreak(fs, &bl);
} }
@@ -841,12 +869,55 @@ static void repeatstat (LexState *ls, int line) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
int repeat_init = luaK_getlabel(fs); int repeat_init = luaK_getlabel(fs);
expdesc v; expdesc v;
Breaklabel bl;
enterbreak(fs, &bl);
setline_and_next(ls); /* trace REPEAT when looping */ setline_and_next(ls); /* trace REPEAT when looping */
block(ls); block(ls);
check_match(ls, TK_UNTIL, TK_REPEAT, line); if (ls->token == TK_END) {
expr(ls, &v); luaK_patchlist(fs, luaK_jump(fs), repeat_init);
luaK_goiftrue(fs, &v, 0); next(ls);
luaK_patchlist(fs, v.u.l.f, repeat_init); }
else {
check_match(ls, TK_UNTIL, TK_REPEAT, line);
expr(ls, &v);
luaK_goiftrue(fs, &v, 0);
luaK_patchlist(fs, v.u.l.f, repeat_init);
}
leavebreak(fs, &bl);
}
static void test_and_bock (LexState *ls, expdesc *v) {
setline_and_next(ls); /* skip IF or ELSEIF */
expr(ls, v); /* cond */
luaK_goiftrue(ls->fs, v, 0);
setline(ls); /* to trace the THEN */
check(ls, TK_THEN);
block(ls); /* `then' part */
}
static void ifstat (LexState *ls, int line) {
/* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
FuncState *fs = ls->fs;
expdesc v;
int escapelist = NO_JUMP;
test_and_bock(ls, &v); /* IF cond THEN block */
while (ls->token == TK_ELSEIF) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchlist(fs, v.u.l.f, luaK_getlabel(fs));
test_and_bock(ls, &v); /* ELSEIF cond THEN block */
}
if (ls->token == TK_ELSE) {
luaK_concat(fs, &escapelist, luaK_jump(fs));
luaK_patchlist(fs, v.u.l.f, luaK_getlabel(fs));
setline_and_next(ls); /* skip ELSE */
block(ls); /* `else' part */
}
else
luaK_concat(fs, &escapelist, v.u.l.f);
luaK_patchlist(fs, escapelist, luaK_getlabel(fs));
check_END(ls, TK_IF, line);
} }
@@ -932,42 +1003,11 @@ static void namestat (LexState *ls) {
} }
static void ifpart (LexState *ls) {
/* ifpart -> cond THEN block (ELSEIF ifpart | [ELSE block] END) */
FuncState *fs = ls->fs;
expdesc v;
int elseinit;
setline_and_next(ls); /* skip IF or ELSEIF */
expr(ls, &v); /* cond */
luaK_goiftrue(fs, &v, 0);
setline(ls); /* to trace the THEN */
check(ls, TK_THEN);
block(ls); /* `then' part */
luaK_S(fs, OP_JMP, 0, 0); /* 2nd jump: over `else' part */
elseinit = luaK_getlabel(fs); /* address of 2nd jump == elseinit-1 */
if (ls->token == TK_ELSEIF)
ifpart(ls);
else if (ls->token == TK_ELSE) {
setline_and_next(ls); /* skip ELSE */
block(ls); /* `else' part */
}
if (fs->pc > elseinit) { /* is there an `else' part? */
luaK_fixjump(fs, elseinit-1, luaK_getlabel(fs)); /* fix 2nd jump */
}
else { /* no else part */
fs->pc--; /* remove 2nd jump */
elseinit = luaK_getlabel(fs); /* `elseinit' points to end */
}
luaK_patchlist(fs, v.u.l.f, elseinit); /* fix 1st jump to `else' part */
}
static int stat (LexState *ls) { static int stat (LexState *ls) {
int line = ls->linenumber; /* may be needed for error messages */ int line = ls->linenumber; /* may be needed for error messages */
switch (ls->token) { switch (ls->token) {
case TK_IF: /* stat -> IF ifpart END */ case TK_IF: /* stat -> ifstat */
ifpart(ls); ifstat(ls, line);
check_END(ls, TK_IF, line);
break; break;
case TK_WHILE: /* stat -> whilestat */ case TK_WHILE: /* stat -> whilestat */
@@ -1058,15 +1098,30 @@ static void body (LexState *ls, int needself, int line) {
static void ret (LexState *ls) { static void ret (LexState *ls) {
/* ret -> [RETURN explist sc] */ /* ret -> [RETURN explist sc | BREAK sc] */
if (ls->token == TK_RETURN) { FuncState *fs = ls->fs;
FuncState *fs = ls->fs; switch (ls->token) {
int nexps; /* number of expressions returned */ case TK_RETURN: {
setline_and_next(ls); /* skip RETURN */ int nexps; /* number of expressions returned */
nexps = explist(ls); setline_and_next(ls); /* skip RETURN */
luaK_retcode(fs, ls->fs->nlocalvar, nexps); nexps = explist(ls);
fs->stacksize = fs->nlocalvar; /* removes all temp values */ luaK_retcode(fs, ls->fs->nlocalvar, nexps);
optional(ls, ';'); fs->stacklevel = fs->nlocalvar; /* removes all temp values */
optional(ls, ';');
break;
}
case TK_BREAK: {
Breaklabel *bl = fs->bl;
int currentlevel = fs->stacklevel;
if (bl == NULL)
luaK_error(ls, "no breakable structure to break");
setline_and_next(ls); /* skip BREAK */
luaK_adjuststack(fs, currentlevel - bl->stacklevel);
luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
optional(ls, ';');
fs->stacklevel = currentlevel;
break;
}
} }
} }
@@ -1076,7 +1131,7 @@ static void ret (LexState *ls) {
static void chunk (LexState *ls) { static void chunk (LexState *ls) {
/* chunk -> { stat [;] } ret */ /* chunk -> { stat [;] } ret */
while (stat(ls)) { while (stat(ls)) {
LUA_ASSERT(ls->L, ls->fs->stacksize == ls->fs->nlocalvar, LUA_ASSERT(ls->L, ls->fs->stacklevel == ls->fs->nlocalvar,
"stack size != # local vars"); "stack size != # local vars");
optional(ls, ';'); optional(ls, ';');
} }

7
lparser.h
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lparser.h,v 1.13 2000/03/13 20:37:16 roberto Exp roberto $ ** $Id: lparser.h,v 1.14 2000/03/24 17:26:08 roberto Exp roberto $
** LL(1) Parser and code generator for Lua ** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -34,8 +34,6 @@ typedef struct expdesc {
} expdesc; } expdesc;
#define NO_JUMP (-1) /* marks end of patch list */
/* state needed to generate code for a given function */ /* state needed to generate code for a given function */
typedef struct FuncState { typedef struct FuncState {
@@ -45,11 +43,12 @@ typedef struct FuncState {
struct lua_State *L; /* copy of the Lua state */ struct lua_State *L; /* copy of the Lua state */
int pc; /* next position to code */ int pc; /* next position to code */
int lasttarget; /* `pc' of last `jump target' */ int lasttarget; /* `pc' of last `jump target' */
int stacksize; /* number of values on activation register */ int stacklevel; /* number of values on activation register */
int nlocalvar; /* number of active local variables */ int nlocalvar; /* number of active local variables */
int nupvalues; /* number of upvalues */ int nupvalues; /* number of upvalues */
int nvars; /* number of entries in f->locvars (-1 if no debug information) */ int nvars; /* number of entries in f->locvars (-1 if no debug information) */
int lastsetline; /* line where last SETLINE was issued */ int lastsetline; /* line where last SETLINE was issued */
struct Breaklabel *bl; /* chain of breakable blocks */
expdesc upvalues[MAXUPVALUES]; /* upvalues */ expdesc upvalues[MAXUPVALUES]; /* upvalues */
TString *localvar[MAXLOCALS]; /* store local variable names */ TString *localvar[MAXLOCALS]; /* store local variable names */
} FuncState; } FuncState;