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https://github.com/lua/lua
synced 2025-03-01 19:41:30 +03:00
checking consistency of jumps (and some other details)
This commit is contained in:
Roberto Ierusalimschy
parent
95da574dbc
commit
3c649ce123
101
ldebug.c
101
ldebug.c
@ -1,5 +1,5 @@
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/*
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** $Id: ldebug.c,v 1.61 2001/02/09 18:37:33 roberto Exp roberto $
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** $Id: ldebug.c,v 1.62 2001/02/09 20:22:29 roberto Exp roberto $
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** Debug Interface
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** See Copyright Notice in lua.h
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*/
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@ -316,49 +316,82 @@ LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
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/*
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** {======================================================
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** Symbolic Execution
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** Symbolic Execution and code checker
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** =======================================================
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*/
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#define check(x) if (!(x)) return 0;
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/*#define check(x) if (!(x)) return 0;*/
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#define check(x) assert(x)
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#define checkjump(pt, pc) check(0 <= (pc) && (pc) < (pt)->sizecode)
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static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
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static int checklineinfo (const Proto *pt) {
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int *lineinfo = pt->lineinfo;
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if (lineinfo == NULL) return 1;
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check(pt->sizelineinfo >= 2 && lineinfo[pt->sizelineinfo-1] == MAX_INT);
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if (*lineinfo < 0) lineinfo++;
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check(*lineinfo == 0);
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return 1;
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}
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static int precheck (const Proto *pt) {
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check(checklineinfo(pt));
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check(pt->maxstacksize <= MAXSTACK);
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check(pt->numparams+pt->is_vararg <= pt->maxstacksize);
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check(GET_OPCODE(pt->code[pt->sizecode-1]) == OP_RETURN);
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return 1;
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}
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/* value for non-initialized entries in array stacklevel */
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#define SL_EMPTY 255
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#define checkstacklevel(sl,top,pc) \
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if (sl) { if (sl[pc] == SL_EMPTY) sl[pc] = top; else check(sl[pc] == top); }
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static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos,
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unsigned char *sl) {
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int stack[MAXSTACK]; /* stores last instruction that changed a stack entry */
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const Instruction *code = pt->code;
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int top = pt->numparams;
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int pc = 0;
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if (pt->is_vararg) /* varargs? */
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top++; /* `arg' */
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check (top <= pt->maxstacksize && pt->maxstacksize <= MAXSTACK);
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checkstacklevel(sl, top, pc);
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while (pc < lastpc) {
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const Instruction i = code[pc++];
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OpCode op = GET_OPCODE(i);
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int push = (int)luaK_opproperties[op].push;
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int pop = (int)luaK_opproperties[op].pop;
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int arg1 = 0;
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int arg2 = 0;
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int push, pop;
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check(op < NUM_OPCODES);
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push = (int)luaK_opproperties[op].push;
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pop = (int)luaK_opproperties[op].pop;
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switch ((enum Mode)luaK_opproperties[op].mode) {
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case iO: break;
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case iU: arg1 = GETARG_U(i); break;
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case iU: arg1 = GETARG_U(i); check(arg1 >= 0); break;
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case iS: arg1 = GETARG_S(i); break;
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case iAB: arg1 = GETARG_A(i); arg2 = GETARG_B(i); break;
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case iAB:
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arg1 = GETARG_A(i); arg2 = GETARG_B(i); check(arg1 >= 0); break;
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}
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check(0 <= top && top <= pt->maxstacksize);
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switch (op) {
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case OP_RETURN: {
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check(arg1 <= top);
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pop = top-arg1;
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break;
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}
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case OP_CALL: {
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if (arg2 == MULT_RET) arg2 = 1;
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check(arg1 < top);
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pop = top-arg1;
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push = arg2;
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break;
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}
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case OP_TAILCALL: {
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check(arg1 <= top);
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check(arg1 < top && arg2 <= top);
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pop = top-arg2;
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break;
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}
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@ -395,7 +428,7 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
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break;
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}
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case OP_SETTABLE: {
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check(2 <= arg1 && arg1 <= top);
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check(3 <= arg1 && arg1 <= top);
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pop = arg2;
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break;
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}
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@ -425,21 +458,24 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
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case OP_JMPGT:
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case OP_JMPGE:
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case OP_JMPT:
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case OP_JMPF:
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case OP_JMPF: {
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checkjump(pt, pc+arg1);
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check(pop <= top);
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checkstacklevel(sl, top-pop, pc+arg1);
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break;
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}
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case OP_JMP:
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case OP_FORLOOP:
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case OP_LFORLOOP: {
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checkjump(pt, pc+arg1);
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break;
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}
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case OP_PUSHNILJMP: {
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checkjump(pt, pc+1);
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checkstacklevel(sl, top, pc+arg1);
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break;
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}
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case OP_JMPONT:
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case OP_JMPONF: {
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int newpc = pc + arg1;
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int newpc = pc+arg1;
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checkjump(pt, newpc);
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checkstacklevel(sl, top, newpc);
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/* jump is forward and do not skip `lastpc' and not full check? */
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if (pc < newpc && newpc <= lastpc && stackpos >= 0) {
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stack[top-1] = pc-1; /* value comes from `and'/`or' */
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@ -448,14 +484,24 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
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}
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break;
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}
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case OP_PUSHNILJMP: {
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check(GET_OPCODE(code[pc]) == OP_PUSHINT); /* only valid sequence */
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break;
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}
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case OP_FORPREP: {
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int newpc = pc-arg1; /* jump is `negative' here */
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check(top >= 3);
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checkjump(pt, pc-arg1); /* jump is `negative' here */
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checkjump(pt, newpc);
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check(GET_OPCODE(code[newpc-1]) == OP_FORLOOP);
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check(GETARG_S(code[newpc-1]) == arg1);
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break;
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}
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case OP_LFORPREP: {
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int newpc = pc-arg1; /* jump is `negative' here */
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check(top >= 1);
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checkjump(pt, pc-arg1); /* jump is `negative' here */
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checkjump(pt, newpc);
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check(GET_OPCODE(code[newpc-1]) == OP_LFORLOOP);
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check(GETARG_S(code[newpc-1]) == arg1);
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break;
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}
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case OP_PUSHINT:
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@ -472,18 +518,21 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
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break;
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}
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}
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check(0 <= pop && 0 <= push);
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check(0 <= top-pop && top+(push-pop) <= pt->maxstacksize);
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top -= pop;
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check(0 <= top && top+push <= pt->maxstacksize);
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while (push--) stack[top++] = pc-1;
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checkstacklevel(sl, top, pc);
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}
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check(GET_OPCODE(code[pt->sizecode-1]) == OP_RETURN);
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return (stackpos >= 0) ? code[stack[stackpos]] : 1;
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}
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int luaG_checkcode (const Proto *pt) {
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return luaG_symbexec(pt, pt->sizecode-1, -1);
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int luaG_checkcode (lua_State *L, const Proto *pt) {
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unsigned char *sl = (unsigned char *)luaO_openspace(L, pt->sizecode);
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int i;
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for (i=0; i<pt->sizecode; i++)
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sl[i] = SL_EMPTY;
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return precheck(pt) && luaG_symbexec(pt, pt->sizecode-1, -1, sl);
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}
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@ -495,7 +544,7 @@ static const char *getobjname (lua_State *L, StkId obj, const char **name) {
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Proto *p = infovalue(func)->func->f.l;
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int pc = currentpc(func);
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int stackpos = obj - (func+1); /* func+1 == function base */
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Instruction i = luaG_symbexec(p, pc, stackpos);
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Instruction i = luaG_symbexec(p, pc, stackpos, NULL);
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lua_assert(pc != -1);
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switch (GET_OPCODE(i)) {
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case OP_GETGLOBAL: {
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