ldebug.c
(5.3.6)
/*
** $Id: ldebug.c,v 2.121.1.2 2017/07/10 17:21:50 roberto Exp $
** Debug Interface
** See Copyright Notice in lua.h
*/
#define ldebug_c
#define LUA_CORE
#include "lprefix.h"
#include <stdarg.h>
#include <stddef.h>
#include <string.h>
#include "lua.h"
#include "lapi.h"
#include "lcode.h"
#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "lvm.h"
#define noLuaClosure(f) ((f) == NULL || (f)->c.tt == LUA_TCCL)
/* Active Lua function (given call info) */
#define ci_func(ci) (clLvalue((ci)->func))
static const char *funcnamefromcode (lua_State *L, CallInfo *ci,
const char **name);
static int currentpc (CallInfo *ci) {
lua_assert(isLua(ci));
return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
}
static int currentline (CallInfo *ci) {
return getfuncline(ci_func(ci)->p, currentpc(ci));
}
/*
** If function yielded, its 'func' can be in the 'extra' field. The
** next function restores 'func' to its correct value for debugging
** purposes. (It exchanges 'func' and 'extra'; so, when called again,
** after debugging, it also "re-restores" ** 'func' to its altered value.
*/
static void swapextra (lua_State *L) {
if (L->status == LUA_YIELD) {
CallInfo *ci = L->ci; /* get function that yielded */
StkId temp = ci->func; /* exchange its 'func' and 'extra' values */
ci->func = restorestack(L, ci->extra);
ci->extra = savestack(L, temp);
}
}
/*
** This function can be called asynchronously (e.g. during a signal).
** Fields 'oldpc', 'basehookcount', and 'hookcount' (set by
** 'resethookcount') are for debug only, and it is no problem if they
** get arbitrary values (causes at most one wrong hook call). 'hookmask'
** is an atomic value. We assume that pointers are atomic too (e.g., gcc
** ensures that for all platforms where it runs). Moreover, 'hook' is
** always checked before being called (see 'luaD_hook').
*/
LUA_API void lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
if (func == NULL || mask == 0) { /* turn off hooks? */
mask = 0;
func = NULL;
}
if (isLua(L->ci))
L->oldpc = L->ci->u.l.savedpc;
L->hook = func;
L->basehookcount = count;
resethookcount(L);
L->hookmask = cast_byte(mask);
}
LUA_API lua_Hook lua_gethook (lua_State *L) {
return L->hook;
}
LUA_API int lua_gethookmask (lua_State *L) {
return L->hookmask;
}
LUA_API int lua_gethookcount (lua_State *L) {
return L->basehookcount;
}
LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
int status;
CallInfo *ci;
if (level < 0) return 0; /* invalid (negative) level */
lua_lock(L);
for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
level--;
if (level == 0 && ci != &L->base_ci) { /* level found? */
status = 1;
ar->i_ci = ci;
}
else status = 0; /* no such level */
lua_unlock(L);
return status;
}
static const char *upvalname (Proto *p, int uv) {
TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
if (s == NULL) return "?";
else return getstr(s);
}
static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
int nparams = clLvalue(ci->func)->p->numparams;
int nvararg = cast_int(ci->u.l.base - ci->func) - nparams;
if (n <= -nvararg)
return NULL; /* no such vararg */
else {
*pos = ci->func + nparams - n;
return "(*vararg)"; /* generic name for any vararg */
}
}
static const char *findlocal (lua_State *L, CallInfo *ci, int n,
StkId *pos) {
const char *name = NULL;
StkId base;
if (isLua(ci)) {
if (n < 0) /* access to vararg values? */
return findvararg(ci, n, pos);
else {
base = ci->u.l.base;
name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
}
}
else
base = ci->func + 1;
if (name == NULL) { /* no 'standard' name? */
StkId limit = (ci == L->ci) ? L->top : ci->next->func;
if (limit - base >= n && n > 0) /* is 'n' inside 'ci' stack? */
name = "(*temporary)"; /* generic name for any valid slot */
else
return NULL; /* no name */
}
*pos = base + (n - 1);
return name;
}
LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
const char *name;
lua_lock(L);
swapextra(L);
if (ar == NULL) { /* information about non-active function? */
if (!isLfunction(L->top - 1)) /* not a Lua function? */
name = NULL;
else /* consider live variables at function start (parameters) */
name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
}
else { /* active function; get information through 'ar' */
StkId pos = NULL; /* to avoid warnings */
name = findlocal(L, ar->i_ci, n, &pos);
if (name) {
setobj2s(L, L->top, pos);
api_incr_top(L);
}
}
swapextra(L);
lua_unlock(L);
return name;
}
LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
StkId pos = NULL; /* to avoid warnings */
const char *name;
lua_lock(L);
swapextra(L);
name = findlocal(L, ar->i_ci, n, &pos);
if (name) {
setobjs2s(L, pos, L->top - 1);
L->top--; /* pop value */
}
swapextra(L);
lua_unlock(L);
return name;
}
static void funcinfo (lua_Debug *ar, Closure *cl) {
if (noLuaClosure(cl)) {
ar->source = "=[C]";
ar->linedefined = -1;
ar->lastlinedefined = -1;
ar->what = "C";
}
else {
Proto *p = cl->l.p;
ar->source = p->source ? getstr(p->source) : "=?";
ar->linedefined = p->linedefined;
ar->lastlinedefined = p->lastlinedefined;
ar->what = (ar->linedefined == 0) ? "main" : "Lua";
}
luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
}
static void collectvalidlines (lua_State *L, Closure *f) {
if (noLuaClosure(f)) {
setnilvalue(L->top);
api_incr_top(L);
}
else {
int i;
TValue v;
int *lineinfo = f->l.p->lineinfo;
Table *t = luaH_new(L); /* new table to store active lines */
sethvalue(L, L->top, t); /* push it on stack */
api_incr_top(L);
setbvalue(&v, 1); /* boolean 'true' to be the value of all indices */
for (i = 0; i < f->l.p->sizelineinfo; i++) /* for all lines with code */
luaH_setint(L, t, lineinfo[i], &v); /* table[line] = true */
}
}
static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
if (ci == NULL) /* no 'ci'? */
return NULL; /* no info */
else if (ci->callstatus & CIST_FIN) { /* is this a finalizer? */
*name = "__gc";
return "metamethod"; /* report it as such */
}
/* calling function is a known Lua function? */
else if (!(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
return funcnamefromcode(L, ci->previous, name);
else return NULL; /* no way to find a name */
}
static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
Closure *f, CallInfo *ci) {
int status = 1;
for (; *what; what++) {
switch (*what) {
case 'S': {
funcinfo(ar, f);
break;
}
case 'l': {
ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
break;
}
case 'u': {
ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
if (noLuaClosure(f)) {
ar->isvararg = 1;
ar->nparams = 0;
}
else {
ar->isvararg = f->l.p->is_vararg;
ar->nparams = f->l.p->numparams;
}
break;
}
case 't': {
ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
break;
}
case 'n': {
ar->namewhat = getfuncname(L, ci, &ar->name);
if (ar->namewhat == NULL) {
ar->namewhat = ""; /* not found */
ar->name = NULL;
}
break;
}
case 'L':
case 'f': /* handled by lua_getinfo */
break;
default: status = 0; /* invalid option */
}
}
return status;
}
LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
int status;
Closure *cl;
CallInfo *ci;
StkId func;
lua_lock(L);
swapextra(L);
if (*what == '>') {
ci = NULL;
func = L->top - 1;
api_check(L, ttisfunction(func), "function expected");
what++; /* skip the '>' */
L->top--; /* pop function */
}
else {
ci = ar->i_ci;
func = ci->func;
lua_assert(ttisfunction(ci->func));
}
cl = ttisclosure(func) ? clvalue(func) : NULL;
status = auxgetinfo(L, what, ar, cl, ci);
if (strchr(what, 'f')) {
setobjs2s(L, L->top, func);
api_incr_top(L);
}
swapextra(L); /* correct before option 'L', which can raise a mem. error */
if (strchr(what, 'L'))
collectvalidlines(L, cl);
lua_unlock(L);
return status;
}
/*
** {======================================================
** Symbolic Execution
** =======================================================
*/
static const char *getobjname (Proto *p, int lastpc, int reg,
const char **name);
/*
** find a "name" for the RK value 'c'
*/
static void kname (Proto *p, int pc, int c, const char **name) {
if (ISK(c)) { /* is 'c' a constant? */
TValue *kvalue = &p->k[INDEXK(c)];
if (ttisstring(kvalue)) { /* literal constant? */
*name = svalue(kvalue); /* it is its own name */
return;
}
/* else no reasonable name found */
}
else { /* 'c' is a register */
const char *what = getobjname(p, pc, c, name); /* search for 'c' */
if (what && *what == 'c') { /* found a constant name? */
return; /* 'name' already filled */
}
/* else no reasonable name found */
}
*name = "?"; /* no reasonable name found */
}
static int filterpc (int pc, int jmptarget) {
if (pc < jmptarget) /* is code conditional (inside a jump)? */
return -1; /* cannot know who sets that register */
else return pc; /* current position sets that register */
}
/*
** try to find last instruction before 'lastpc' that modified register 'reg'
*/
static int findsetreg (Proto *p, int lastpc, int reg) {
int pc;
int setreg = -1; /* keep last instruction that changed 'reg' */
int jmptarget = 0; /* any code before this address is conditional */
for (pc = 0; pc < lastpc; pc++) {
Instruction i = p->code[pc];
OpCode op = GET_OPCODE(i);
int a = GETARG_A(i);
switch (op) {
case OP_LOADNIL: {
int b = GETARG_B(i);
if (a <= reg && reg <= a + b) /* set registers from 'a' to 'a+b' */
setreg = filterpc(pc, jmptarget);
break;
}
case OP_TFORCALL: {
if (reg >= a + 2) /* affect all regs above its base */
setreg = filterpc(pc, jmptarget);
break;
}
case OP_CALL:
case OP_TAILCALL: {
if (reg >= a) /* affect all registers above base */
setreg = filterpc(pc, jmptarget);
break;
}
case OP_JMP: {
int b = GETARG_sBx(i);
int dest = pc + 1 + b;
/* jump is forward and do not skip 'lastpc'? */
if (pc < dest && dest <= lastpc) {
if (dest > jmptarget)
jmptarget = dest; /* update 'jmptarget' */
}
break;
}
default:
if (testAMode(op) && reg == a) /* any instruction that set A */
setreg = filterpc(pc, jmptarget);
break;
}
}
return setreg;
}
static const char *getobjname (Proto *p, int lastpc, int reg,
const char **name) {
int pc;
*name = luaF_getlocalname(p, reg + 1, lastpc);
if (*name) /* is a local? */
return "local";
/* else try symbolic execution */
pc = findsetreg(p, lastpc, reg);
if (pc != -1) { /* could find instruction? */
Instruction i = p->code[pc];
OpCode op = GET_OPCODE(i);
switch (op) {
case OP_MOVE: {
int b = GETARG_B(i); /* move from 'b' to 'a' */
if (b < GETARG_A(i))
return getobjname(p, pc, b, name); /* get name for 'b' */
break;
}
case OP_GETTABUP:
case OP_GETTABLE: {
int k = GETARG_C(i); /* key index */
int t = GETARG_B(i); /* table index */
const char *vn = (op == OP_GETTABLE) /* name of indexed variable */
? luaF_getlocalname(p, t + 1, pc)
: upvalname(p, t);
kname(p, pc, k, name);
return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
}
case OP_GETUPVAL: {
*name = upvalname(p, GETARG_B(i));
return "upvalue";
}
case OP_LOADK:
case OP_LOADKX: {
int b = (op == OP_LOADK) ? GETARG_Bx(i)
: GETARG_Ax(p->code[pc + 1]);
if (ttisstring(&p->k[b])) {
*name = svalue(&p->k[b]);
return "constant";
}
break;
}
case OP_SELF: {
int k = GETARG_C(i); /* key index */
kname(p, pc, k, name);
return "method";
}
default: break; /* go through to return NULL */
}
}
return NULL; /* could not find reasonable name */
}
/*
** Try to find a name for a function based on the code that called it.
** (Only works when function was called by a Lua function.)
** Returns what the name is (e.g., "for iterator", "method",
** "metamethod") and sets '*name' to point to the name.
*/
static const char *funcnamefromcode (lua_State *L, CallInfo *ci,
const char **name) {
TMS tm = (TMS)0; /* (initial value avoids warnings) */
Proto *p = ci_func(ci)->p; /* calling function */
int pc = currentpc(ci); /* calling instruction index */
Instruction i = p->code[pc]; /* calling instruction */
if (ci->callstatus & CIST_HOOKED) { /* was it called inside a hook? */
*name = "?";
return "hook";
}
switch (GET_OPCODE(i)) {
case OP_CALL:
case OP_TAILCALL:
return getobjname(p, pc, GETARG_A(i), name); /* get function name */
case OP_TFORCALL: { /* for iterator */
*name = "for iterator";
return "for iterator";
}
/* other instructions can do calls through metamethods */
case OP_SELF: case OP_GETTABUP: case OP_GETTABLE:
tm = TM_INDEX;
break;
case OP_SETTABUP: case OP_SETTABLE:
tm = TM_NEWINDEX;
break;
case OP_ADD: case OP_SUB: case OP_MUL: case OP_MOD:
case OP_POW: case OP_DIV: case OP_IDIV: case OP_BAND:
case OP_BOR: case OP_BXOR: case OP_SHL: case OP_SHR: {
int offset = cast_int(GET_OPCODE(i)) - cast_int(OP_ADD); /* ORDER OP */
tm = cast(TMS, offset + cast_int(TM_ADD)); /* ORDER TM */
break;
}
case OP_UNM: tm = TM_UNM; break;
case OP_BNOT: tm = TM_BNOT; break;
case OP_LEN: tm = TM_LEN; break;
case OP_CONCAT: tm = TM_CONCAT; break;
case OP_EQ: tm = TM_EQ; break;
case OP_LT: tm = TM_LT; break;
case OP_LE: tm = TM_LE; break;
default:
return NULL; /* cannot find a reasonable name */
}
*name = getstr(G(L)->tmname[tm]);
return "metamethod";
}
/* }====================================================== */
/*
** The subtraction of two potentially unrelated pointers is
** not ISO C, but it should not crash a program; the subsequent
** checks are ISO C and ensure a correct result.
*/
static int isinstack (CallInfo *ci, const TValue *o) {
ptrdiff_t i = o - ci->u.l.base;
return (0 <= i && i < (ci->top - ci->u.l.base) && ci->u.l.base + i == o);
}
/*
** Checks whether value 'o' came from an upvalue. (That can only happen
** with instructions OP_GETTABUP/OP_SETTABUP, which operate directly on
** upvalues.)
*/
static const char *getupvalname (CallInfo *ci, const TValue *o,
const char **name) {
LClosure *c = ci_func(ci);
int i;
for (i = 0; i < c->nupvalues; i++) {
if (c->upvals[i]->v == o) {
*name = upvalname(c->p, i);
return "upvalue";
}
}
return NULL;
}
static const char *varinfo (lua_State *L, const TValue *o) {
const char *name = NULL; /* to avoid warnings */
CallInfo *ci = L->ci;
const char *kind = NULL;
if (isLua(ci)) {
kind = getupvalname(ci, o, &name); /* check whether 'o' is an upvalue */
if (!kind && isinstack(ci, o)) /* no? try a register */
kind = getobjname(ci_func(ci)->p, currentpc(ci),
cast_int(o - ci->u.l.base), &name);
}
return (kind) ? luaO_pushfstring(L, " (%s '%s')", kind, name) : "";
}
l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
const char *t = luaT_objtypename(L, o);
luaG_runerror(L, "attempt to %s a %s value%s", op, t, varinfo(L, o));
}
l_noret luaG_concaterror (lua_State *L, const TValue *p1, const TValue *p2) {
if (ttisstring(p1) || cvt2str(p1)) p1 = p2;
luaG_typeerror(L, p1, "concatenate");
}
l_noret luaG_opinterror (lua_State *L, const TValue *p1,
const TValue *p2, const char *msg) {
lua_Number temp;
if (!tonumber(p1, &temp)) /* first operand is wrong? */
p2 = p1; /* now second is wrong */
luaG_typeerror(L, p2, msg);
}
/*
** Error when both values are convertible to numbers, but not to integers
*/
l_noret luaG_tointerror (lua_State *L, const TValue *p1, const TValue *p2) {
lua_Integer temp;
if (!tointeger(p1, &temp))
p2 = p1;
luaG_runerror(L, "number%s has no integer representation", varinfo(L, p2));
}
l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
const char *t1 = luaT_objtypename(L, p1);
const char *t2 = luaT_objtypename(L, p2);
if (strcmp(t1, t2) == 0)
luaG_runerror(L, "attempt to compare two %s values", t1);
else
luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
}
/* add src:line information to 'msg' */
const char *luaG_addinfo (lua_State *L, const char *msg, TString *src,
int line) {
char buff[LUA_IDSIZE];
if (src)
luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
else { /* no source available; use "?" instead */
buff[0] = '?'; buff[1] = '\0';
}
return luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
}
l_noret luaG_errormsg (lua_State *L) {
if (L->errfunc != 0) { /* is there an error handling function? */
StkId errfunc = restorestack(L, L->errfunc);
setobjs2s(L, L->top, L->top - 1); /* move argument */
setobjs2s(L, L->top - 1, errfunc); /* push function */
L->top++; /* assume EXTRA_STACK */
luaD_callnoyield(L, L->top - 2, 1); /* call it */
}
luaD_throw(L, LUA_ERRRUN);
}
l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
CallInfo *ci = L->ci;
const char *msg;
va_list argp;
luaC_checkGC(L); /* error message uses memory */
va_start(argp, fmt);
msg = luaO_pushvfstring(L, fmt, argp); /* format message */
va_end(argp);
if (isLua(ci)) /* if Lua function, add source:line information */
luaG_addinfo(L, msg, ci_func(ci)->p->source, currentline(ci));
luaG_errormsg(L);
}
void luaG_traceexec (lua_State *L) {
CallInfo *ci = L->ci;
lu_byte mask = L->hookmask;
int counthook = (--L->hookcount == 0 && (mask & LUA_MASKCOUNT));
if (counthook)
resethookcount(L); /* reset count */
else if (!(mask & LUA_MASKLINE))
return; /* no line hook and count != 0; nothing to be done */
if (ci->callstatus & CIST_HOOKYIELD) { /* called hook last time? */
ci->callstatus &= ~CIST_HOOKYIELD; /* erase mark */
return; /* do not call hook again (VM yielded, so it did not move) */
}
if (counthook)
luaD_hook(L, LUA_HOOKCOUNT, -1); /* call count hook */
if (mask & LUA_MASKLINE) {
Proto *p = ci_func(ci)->p;
int npc = pcRel(ci->u.l.savedpc, p);
int newline = getfuncline(p, npc);
if (npc == 0 || /* call linehook when enter a new function, */
ci->u.l.savedpc <= L->oldpc || /* when jump back (loop), or when */
newline != getfuncline(p, pcRel(L->oldpc, p))) /* enter a new line */
luaD_hook(L, LUA_HOOKLINE, newline); /* call line hook */
}
L->oldpc = ci->u.l.savedpc;
if (L->status == LUA_YIELD) { /* did hook yield? */
if (counthook)
L->hookcount = 1; /* undo decrement to zero */
ci->u.l.savedpc--; /* undo increment (resume will increment it again) */
ci->callstatus |= CIST_HOOKYIELD; /* mark that it yielded */
ci->func = L->top - 1; /* protect stack below results */
luaD_throw(L, LUA_YIELD);
}
}