/*

** $Id: ldebug.c $

** 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 LuaClosure(f) ((f) != NULL && (f)->c.tt == LUA_VLCL)

static const char *funcnamefromcall (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);

}

/*

** Get a "base line" to find the line corresponding to an instruction.

** Base lines are regularly placed at MAXIWTHABS intervals, so usually

** an integer division gets the right place. When the source file has

** large sequences of empty/comment lines, it may need extra entries,

** so the original estimate needs a correction.

** If the original estimate is -1, the initial 'if' ensures that the

** 'while' will run at least once.

** The assertion that the estimate is a lower bound for the correct base

** is valid as long as the debug info has been generated with the same

** value for MAXIWTHABS or smaller. (Previous releases use a little

** smaller value.)

*/

static int getbaseline (const Proto *f, int pc, int *basepc) {

if (f->sizeabslineinfo == 0 || pc < f->abslineinfo[0].pc) {

*basepc = -1; /* start from the beginning */

return f->linedefined;

}

else {

int i = cast_uint(pc) / MAXIWTHABS - 1; /* get an estimate */

/* estimate must be a lower bound of the correct base */

lua_assert(i < 0 ||

(i < f->sizeabslineinfo && f->abslineinfo[i].pc <= pc));

while (i 1 < f->sizeabslineinfo && pc >= f->abslineinfo[i 1].pc)

i ; /* low estimate; adjust it */

*basepc = f->abslineinfo[i].pc;

return f->abslineinfo[i].line;

}

}

/*

** Get the line corresponding to instruction 'pc' in function 'f';

** first gets a base line and from there does the increments until

** the desired instruction.

*/

int luaG_getfuncline (const Proto *f, int pc) {

if (f->lineinfo == NULL) /* no debug information? */

return -1;

else {

int basepc;

int baseline = getbaseline(f, pc, &basepc);

while (basepc < pc) { /* walk until given instruction */

lua_assert(f->lineinfo[basepc] != ABSLINEINFO);

baseline = f->lineinfo[basepc]; /* correct line */

}

return baseline;

}

}

static int getcurrentline (CallInfo *ci) {

return luaG_getfuncline(ci_func(ci)->p, currentpc(ci));

}

/*

** Set 'trap' for all active Lua frames.

** This function can be called during a signal, under "reasonable"

** assumptions. A new 'ci' is completely linked in the list before it

** becomes part of the "active" list, and we assume that pointers are

** atomic; see comment in next function.

** (A compiler doing interprocedural optimizations could, theoretically,

** reorder memory writes in such a way that the list could be

** temporarily broken while inserting a new element. We simply assume it

** has no good reasons to do that.)

*/

static void settraps (CallInfo *ci) {

for (; ci != NULL; ci = ci->previous)

if (isLua(ci))

ci->u.l.trap = 1;

}

/*

** This function can be called during a signal, under "reasonable"

** assumptions.

** Fields '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;

}

L->hook = func;

L->basehookcount = count;

resethookcount(L);

L->hookmask = cast_byte(mask);

if (mask)

settraps(L->ci); /* to trace inside 'luaV_execute' */

}

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 (const 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) {

if (clLvalue(s2v(ci->func.p))->p->is_vararg) {

int nextra = ci->u.l.nextraargs;

if (n >= -nextra) { /* 'n' is negative */

*pos = ci->func.p - nextra - (n 1);

return "(vararg)"; /* generic name for any vararg */

}

}

return NULL; /* no such vararg */

}

const char *luaG_findlocal (lua_State *L, CallInfo *ci, int n, StkId *pos) {

StkId base = ci->func.p 1;

const char *name = NULL;

if (isLua(ci)) {

if (n < 0) /* access to vararg values? */

return findvararg(ci, n, pos);

else

name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));

}

if (name == NULL) { /* no 'standard' name? */

StkId limit = (ci == L->ci) ? L->top.p : ci->next->func.p;

if (limit - base >= n && n > 0) { /* is 'n' inside 'ci' stack? */

/* generic name for any valid slot */

name = isLua(ci) ? "(temporary)" : "(C temporary)";

}

else

return NULL; /* no name */

}

if (pos)

*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);

if (ar == NULL) { /* information about non-active function? */

if (!isLfunction(s2v(L->top.p - 1))) /* not a Lua function? */

name = NULL;

else /* consider live variables at function start (parameters) */

name = luaF_getlocalname(clLvalue(s2v(L->top.p - 1))->p, n, 0);

}

else { /* active function; get information through 'ar' */

StkId pos = NULL; /* to avoid warnings */

name = luaG_findlocal(L, ar->i_ci, n, &pos);

if (name) {

setobjs2s(L, L->top.p, pos);

api_incr_top(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);

name = luaG_findlocal(L, ar->i_ci, n, &pos);

if (name) {

setobjs2s(L, pos, L->top.p - 1);

L->top.p--; /* pop value */

}

lua_unlock(L);

return name;

}

static void funcinfo (lua_Debug *ar, Closure *cl) {

if (!LuaClosure(cl)) {

ar->source = "=[C]";

ar->srclen = LL("=[C]");

ar->linedefined = -1;

ar->lastlinedefined = -1;

ar->what = "C";

}

else {

const Proto *p = cl->l.p;

if (p->source) {

ar->source = getstr(p->source);

ar->srclen = tsslen(p->source);

}

else {

ar->source = "=?";

ar->srclen = LL("=?");

}

ar->linedefined = p->linedefined;

ar->lastlinedefined = p->lastlinedefined;

ar->what = (ar->linedefined == 0) ? "main" : "Lua";

}

luaO_chunkid(ar->short_src, ar->source, ar->srclen);

}

static int nextline (const Proto *p, int currentline, int pc) {

if (p->lineinfo[pc] != ABSLINEINFO)

return currentline p->lineinfo[pc];

else

return luaG_getfuncline(p, pc);

}

static void collectvalidlines (lua_State *L, Closure *f) {

if (!LuaClosure(f)) {

setnilvalue(s2v(L->top.p));

api_incr_top(L);

}

else {

const Proto *p = f->l.p;

int currentline = p->linedefined;

Table *t = luaH_new(L); /* new table to store active lines */

sethvalue2s(L, L->top.p, t); /* push it on stack */

api_incr_top(L);

if (p->lineinfo != NULL) { /* proto with debug information? */

int i;

TValue v;

setbtvalue(&v); /* boolean 'true' to be the value of all indices */

if (!p->is_vararg) /* regular function? */

i = 0; /* consider all instructions */

else { /* vararg function */

lua_assert(GET_OPCODE(p->code[0]) == OP_VARARGPREP);

currentline = nextline(p, currentline, 0);

i = 1; /* skip first instruction (OP_VARARGPREP) */

}

for (; i < p->sizelineinfo; i ) { /* for each instruction */

currentline = nextline(p, currentline, i); /* get its line */

luaH_setint(L, t, currentline, &v); /* table[line] = true */

}

}

}

}

static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {

/* calling function is a known function? */

if (ci != NULL && !(ci->callstatus & CIST_TAIL))

return funcnamefromcall(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)) ? getcurrentline(ci) : -1;

break;

}

case 'u': {

ar->nups = (f == NULL) ? 0 : f->c.nupvalues;

if (!LuaClosure(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 'r': {

if (ci == NULL || !(ci->callstatus & CIST_TRAN))

ar->ftransfer = ar->ntransfer = 0;

else {

ar->ftransfer = ci->u2.transferinfo.ftransfer;

ar->ntransfer = ci->u2.transferinfo.ntransfer;

}

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;

TValue *func;

lua_lock(L);

if (*what == '>') {

ci = NULL;

func = s2v(L->top.p - 1);

api_check(L, ttisfunction(func), "function expected");

what ; /* skip the '>' */

L->top.p--; /* pop function */

}

else {

ci = ar->i_ci;

func = s2v(ci->func.p);

lua_assert(ttisfunction(func));

}

cl = ttisclosure(func) ? clvalue(func) : NULL;

status = auxgetinfo(L, what, ar, cl, ci);

if (strchr(what, 'f')) {

setobj2s(L, L->top.p, func);

api_incr_top(L);

}

if (strchr(what, 'L'))

collectvalidlines(L, cl);

lua_unlock(L);

return status;

}

/*

** {======================================================

** Symbolic Execution

** =======================================================

*/

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 (const 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 */

if (testMMMode(GET_OPCODE(p->code[lastpc])))

lastpc--; /* previous instruction was not actually executed */

for (pc = 0; pc < lastpc; pc ) {

Instruction i = p->code[pc];

OpCode op = GET_OPCODE(i);

int a = GETARG_A(i);

int change; /* true if current instruction changed 'reg' */

switch (op) {

case OP_LOADNIL: { /* set registers from 'a' to 'a b' */

int b = GETARG_B(i);

change = (a <= reg && reg <= a b);

break;

}

case OP_TFORCALL: { /* affect all regs above its base */

change = (reg >= a 2);

break;

}

case OP_CALL:

case OP_TAILCALL: { /* affect all registers above base */

change = (reg >= a);

break;

}

case OP_JMP: { /* doesn't change registers, but changes 'jmptarget' */

int b = GETARG_sJ(i);

int dest = pc 1 b;

/* jump does not skip 'lastpc' and is larger than current one? */

if (dest <= lastpc && dest > jmptarget)

jmptarget = dest; /* update 'jmptarget' */

change = 0;

break;

}

default: /* any instruction that sets A */

change = (testAMode(op) && reg == a);

break;

}

if (change)

setreg = filterpc(pc, jmptarget);

}

return setreg;

}

/*

** Find a "name" for the constant 'c'.

*/

static const char *kname (const Proto *p, int index, const char **name) {

TValue *kvalue = &p->k[index];

if (ttisstring(kvalue)) {

*name = getstr(tsvalue(kvalue));

return "constant";

}

else {

*name = "?";

return NULL;

}

}

static const char *basicgetobjname (const Proto *p, int *ppc, int reg,

const char **name) {

int pc = *ppc;

*name = luaF_getlocalname(p, reg 1, pc);

if (*name) /* is a local? */

return "local";

/* else try symbolic execution */

*ppc = pc = findsetreg(p, pc, 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 basicgetobjname(p, ppc, b, name); /* get name for 'b' */

break;

}

case OP_GETUPVAL: {

*name = upvalname(p, GETARG_B(i));

return "upvalue";

}

case OP_LOADK: return kname(p, GETARG_Bx(i), name);

case OP_LOADKX: return kname(p, GETARG_Ax(p->code[pc 1]), name);

default: break;

}

}

return NULL; /* could not find reasonable name */

}

/*

** Find a "name" for the register 'c'.

*/

static void rname (const Proto *p, int pc, int c, const char **name) {

const char *what = basicgetobjname(p, &pc, c, name); /* search for 'c' */

if (!(what && *what == 'c')) /* did not find a constant name? */

*name = "?";

}

/*

** Find a "name" for a 'C' value in an RK instruction.

*/

static void rkname (const Proto *p, int pc, Instruction i, const char **name) {

int c = GETARG_C(i); /* key index */

if (GETARG_k(i)) /* is 'c' a constant? */

kname(p, c, name);

else /* 'c' is a register */

rname(p, pc, c, name);

}

/*

** Check whether table being indexed by instruction 'i' is the

** environment '_ENV'

*/

static const char *isEnv (const Proto *p, int pc, Instruction i, int isup) {

int t = GETARG_B(i); /* table index */

const char *name; /* name of indexed variable */

if (isup) /* is 't' an upvalue? */

name = upvalname(p, t);

else /* 't' is a register */

basicgetobjname(p, &pc, t, &name);

return (name && strcmp(name, LUA_ENV) == 0) ? "global" : "field";

}

/*

** Extend 'basicgetobjname' to handle table accesses

*/

static const char *getobjname (const Proto *p, int lastpc, int reg,

const char **name) {

const char *kind = basicgetobjname(p, &lastpc, reg, name);

if (kind != NULL)

return kind;

else if (lastpc != -1) { /* could find instruction? */

Instruction i = p->code[lastpc];

OpCode op = GET_OPCODE(i);

switch (op) {

case OP_GETTABUP: {

int k = GETARG_C(i); /* key index */

kname(p, k, name);

return isEnv(p, lastpc, i, 1);

}

case OP_GETTABLE: {

int k = GETARG_C(i); /* key index */

rname(p, lastpc, k, name);

return isEnv(p, lastpc, i, 0);

}

case OP_GETI: {

*name = "integer index";

return "field";

}

case OP_GETFIELD: {

int k = GETARG_C(i); /* key index */

kname(p, k, name);

return isEnv(p, lastpc, i, 0);

}

case OP_SELF: {

rkname(p, lastpc, i, 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, const Proto *p,

int pc, const char **name) {

TMS tm = (TMS)0; /* (initial value avoids warnings) */

Instruction i = p->code[pc]; /* calling instruction */

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:

case OP_GETI: case OP_GETFIELD:

tm = TM_INDEX;

break;

case OP_SETTABUP: case OP_SETTABLE: case OP_SETI: case OP_SETFIELD:

tm = TM_NEWINDEX;

break;

case OP_MMBIN: case OP_MMBINI: case OP_MMBINK: {

tm = cast(TMS, GETARG_C(i));

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;

/* no cases for OP_EQI and OP_EQK, as they don't call metamethods */

case OP_LT: case OP_LTI: case OP_GTI: tm = TM_LT; break;

case OP_LE: case OP_LEI: case OP_GEI: tm = TM_LE; break;

case OP_CLOSE: case OP_RETURN: tm = TM_CLOSE; break;

default:

return NULL; /* cannot find a reasonable name */

}

*name = getshrstr(G(L)->tmname[tm]) 2;

return "metamethod";

}

/*

** Try to find a name for a function based on how it was called.

*/

static const char *funcnamefromcall (lua_State *L, CallInfo *ci,

const char **name) {

if (ci->callstatus & CIST_HOOKED) { /* was it called inside a hook? */

*name = "?";

return "hook";

}

else if (ci->callstatus & CIST_FIN) { /* was it called as a finalizer? */

*name = "__gc";

return "metamethod"; /* report it as such */

}

else if (isLua(ci))

return funcnamefromcode(L, ci_func(ci)->p, currentpc(ci), name);

else

return NULL;

}

/* }====================================================== */

/*

** Check whether pointer 'o' points to some value in the stack frame of

** the current function and, if so, returns its index. Because 'o' may

** not point to a value in this stack, we cannot compare it with the

** region boundaries (undefined behavior in ISO C).

*/

static int instack (CallInfo *ci, const TValue *o) {

int pos;

StkId base = ci->func.p 1;

for (pos = 0; base pos < ci->top.p; pos ) {

if (o == s2v(base pos))

return pos;

}

return -1; /* not found */

}

/*

** 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.p == o) {

*name = upvalname(c->p, i);

return "upvalue";

}

}

return NULL;

}

static const char *formatvarinfo (lua_State *L, const char *kind,

const char *name) {

if (kind == NULL)

return ""; /* no information */

else

return luaO_pushfstring(L, " (%s '%s')", kind, name);

}

/*

** Build a string with a "description" for the value 'o', such as

** "variable 'x'" or "upvalue 'y'".

*/

static const char *varinfo (lua_State *L, const TValue *o) {

CallInfo *ci = L->ci;

const char *name = NULL; /* to avoid warnings */

const char *kind = NULL;

if (isLua(ci)) {

kind = getupvalname(ci, o, &name); /* check whether 'o' is an upvalue */

if (!kind) { /* not an upvalue? */

int reg = instack(ci, o); /* try a register */

if (reg >= 0) /* is 'o' a register? */

kind = getobjname(ci_func(ci)->p, currentpc(ci), reg, &name);

}

}

return formatvarinfo(L, kind, name);

}

/*

** Raise a type error

*/

static l_noret typeerror (lua_State *L, const TValue *o, const char *op,

const char *extra) {

const char *t = luaT_objtypename(L, o);

luaG_runerror(L, "attempt to %s a %s value%s", op, t, extra);

}

/*

** Raise a type error with "standard" information about the faulty

** object 'o' (using 'varinfo').

*/

l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {

typeerror(L, o, op, varinfo(L, o));

}

/*

** Raise an error for calling a non-callable object. Try to find a name

** for the object based on how it was called ('funcnamefromcall'); if it

** cannot get a name there, try 'varinfo'.

*/

l_noret luaG_callerror (lua_State *L, const TValue *o) {

CallInfo *ci = L->ci;

const char *name = NULL; /* to avoid warnings */

const char *kind = funcnamefromcall(L, ci, &name);

const char *extra = kind ? formatvarinfo(L, kind, name) : varinfo(L, o);

typeerror(L, o, "call", extra);

}

l_noret luaG_forerror (lua_State *L, const TValue *o, const char *what) {

luaG_runerror(L, "bad 'for' %s (number expected, got %s)",

what, luaT_objtypename(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) {

if (!ttisnumber(p1)) /* 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 (!luaV_tointegerns(p1, &temp, LUA_FLOORN2I))

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), tsslen(src));

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);

lua_assert(ttisfunction(s2v(errfunc)));

setobjs2s(L, L->top.p, L->top.p - 1); /* move argument */

setobjs2s(L, L->top.p - 1, errfunc); /* push function */

L->top.p ; /* assume EXTRA_STACK */

luaD_callnoyield(L, L->top.p - 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, getcurrentline(ci));

setobjs2s(L, L->top.p - 2, L->top.p - 1); /* remove 'msg' */

L->top.p--;

}

luaG_errormsg(L);

}

/*

** Check whether new instruction 'newpc' is in a different line from

** previous instruction 'oldpc'. More often than not, 'newpc' is only

** one or a few instructions after 'oldpc' (it must be after, see

** caller), so try to avoid calling 'luaG_getfuncline'. If they are

** too far apart, there is a good chance of a ABSLINEINFO in the way,

** so it goes directly to 'luaG_getfuncline'.

*/

static int changedline (const Proto *p, int oldpc, int newpc) {

if (p->lineinfo == NULL) /* no debug information? */

return 0;

if (newpc - oldpc < MAXIWTHABS / 2) { /* not too far apart? */

int delta = 0; /* line difference */

int pc = oldpc;

for (;;) {

int lineinfo = p->lineinfo[ pc];

if (lineinfo == ABSLINEINFO)

break; /* cannot compute delta; fall through */

delta = lineinfo;

if (pc == newpc)

return (delta != 0); /* delta computed successfully */

}

}

/* either instructions are too far apart or there is an absolute line

info in the way; compute line difference explicitly */

return (luaG_getfuncline(p, oldpc) != luaG_getfuncline(p, newpc));

}

/*

** Traces Lua calls. If code is running the first instruction of a function,

** and function is not vararg, and it is not coming from an yield,

** calls 'luaD_hookcall'. (Vararg functions will call 'luaD_hookcall'

** after adjusting its variable arguments; otherwise, they could call

** a line/count hook before the call hook. Functions coming from

** an yield already called 'luaD_hookcall' before yielding.)

*/

int luaG_tracecall (lua_State *L) {

CallInfo *ci = L->ci;

Proto *p = ci_func(ci)->p;

ci->u.l.trap = 1; /* ensure hooks will be checked */

if (ci->u.l.savedpc == p->code) { /* first instruction (not resuming)? */

if (p->is_vararg)

return 0; /* hooks will start at VARARGPREP instruction */

else if (!(ci->callstatus & CIST_HOOKYIELD)) /* not yieded? */

luaD_hookcall(L, ci); /* check 'call' hook */

}

return 1; /* keep 'trap' on */

}

/*

** Traces the execution of a Lua function. Called before the execution

** of each opcode, when debug is on. 'L->oldpc' stores the last

** instruction traced, to detect line changes. When entering a new

** function, 'npci' will be zero and will test as a new line whatever

** the value of 'oldpc'. Some exceptional conditions may return to

** a function without setting 'oldpc'. In that case, 'oldpc' may be

** invalid; if so, use zero as a valid value. (A wrong but valid 'oldpc'

** at most causes an extra call to a line hook.)

** This function is not "Protected" when called, so it should correct

** 'L->top.p' before calling anything that can run the GC.

*/

int luaG_traceexec (lua_State *L, const Instruction *pc) {

CallInfo *ci = L->ci;

lu_byte mask = L->hookmask;

const Proto *p = ci_func(ci)->p;

int counthook;

if (!(mask & (LUA_MASKLINE | LUA_MASKCOUNT))) { /* no hooks? */

ci->u.l.trap = 0; /* don't need to stop again */

return 0; /* turn off 'trap' */

}

pc ; /* reference is always next instruction */

ci->u.l.savedpc = pc; /* save 'pc' */

counthook = (mask & LUA_MASKCOUNT) && (--L->hookcount == 0);

if (counthook)

resethookcount(L); /* reset count */

else if (!(mask & LUA_MASKLINE))

return 1; /* no line hook and count != 0; nothing to be done now */

if (ci->callstatus & CIST_HOOKYIELD) { /* hook yielded last time? */

ci->callstatus &= ~CIST_HOOKYIELD; /* erase mark */

return 1; /* do not call hook again (VM yielded, so it did not move) */

}

if (!isIT(*(ci->u.l.savedpc - 1))) /* top not being used? */

L->top.p = ci->top.p; /* correct top */

if (counthook)

luaD_hook(L, LUA_HOOKCOUNT, -1, 0, 0); /* call count hook */

if (mask & LUA_MASKLINE) {

/* 'L->oldpc' may be invalid; use zero in this case */

int oldpc = (L->oldpc < p->sizecode) ? L->oldpc : 0;

int npci = pcRel(pc, p);

if (npci <= oldpc || /* call hook when jump back (loop), */

changedline(p, oldpc, npci)) { /* or when enter new line */

int newline = luaG_getfuncline(p, npci);

luaD_hook(L, LUA_HOOKLINE, newline, 0, 0); /* call line hook */

}

L->oldpc = npci; /* 'pc' of last call to line hook */

}

if (L->status == LUA_YIELD) { /* did hook yield? */

if (counthook)

L->hookcount = 1; /* undo decrement to zero */

ci->callstatus |= CIST_HOOKYIELD; /* mark that it yielded */

luaD_throw(L, LUA_YIELD);

}

return 1; /* keep 'trap' on */

}