lua/ldebug.c
Roberto Ierusalimschy df13f25948 First version of OP_MMBIN opcodes
In arithmetic/bitwise operators, the call to metamethods is made
in a separate opcode following the main one. (The main
opcode skips this next one when the operation succeeds.) This
change reduces slightly the size of the binary and the complexity
of the arithmetic/bitwise opcodes. It also simplfies the treatment
of errors and yeld/resume in these operations, as there are much
fewer cases to consider. (Only OP_MMBIN/OP_MMBINI/OP_MMBINK,
instead of all variants of all arithmetic/bitwise operators.)
2019-08-27 13:59:39 -03:00

850 lines
24 KiB
C

/*
** $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 noLuaClosure(f) ((f) == NULL || (f)->c.tt == LUA_TCCL)
/* Active Lua function (given call info) */
#define ci_func(ci) (clLvalue(s2v((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);
}
/*
** Get a "base line" to find the line corresponding to an instruction.
** For that, search the array of absolute line info for the largest saved
** instruction smaller or equal to the wanted instruction. A special
** case is when there is no absolute info or the instruction is before
** the first absolute one.
*/
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 {
unsigned int i;
if (pc >= f->abslineinfo[f->sizeabslineinfo - 1].pc)
i = f->sizeabslineinfo - 1; /* instruction is after last saved one */
else { /* binary search */
unsigned int j = f->sizeabslineinfo - 1; /* pc < anchorlines[j] */
i = 0; /* abslineinfo[i] <= pc */
while (i < j - 1) {
unsigned int m = (j + i) / 2;
if (pc >= f->abslineinfo[m].pc)
i = m;
else
j = m;
}
}
*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 currentline (CallInfo *ci) {
return luaG_getfuncline(ci_func(ci)->p, currentpc(ci));
}
/*
** This function can be called asynchronously (e.g. 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).
** (If we traverse one more item, there is no problem. If we traverse
** one less item, the worst that can happen is that the signal will
** not interrupt the script.)
*/
static void settraps (CallInfo *ci) {
for (; ci != NULL; ci = ci->previous)
if (isLua(ci))
ci->u.l.trap = 1;
}
/*
** This function can be called asynchronously (e.g. during a signal),
** under "reasonable" assumptions.
** 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);
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->is_vararg) {
int nextra = ci->u.l.nextraargs;
if (n <= nextra) {
*pos = ci->func - 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 + 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 : ci->next->func;
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 - 1))) /* not a Lua function? */
name = NULL;
else /* consider live variables at function start (parameters) */
name = luaF_getlocalname(clLvalue(s2v(L->top - 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, 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 - 1);
L->top--; /* pop value */
}
lua_unlock(L);
return name;
}
static void funcinfo (lua_Debug *ar, Closure *cl) {
if (noLuaClosure(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 (noLuaClosure(f)) {
setnilvalue(s2v(L->top));
api_incr_top(L);
}
else {
int i;
TValue v;
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, 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 < p->sizelineinfo; i++) { /* for all lines with code */
currentline = nextline(p, currentline, i);
luaH_setint(L, t, currentline, &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 '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 - 1);
api_check(L, ttisfunction(func), "function expected");
what++; /* skip the '>' */
L->top--; /* pop function */
}
else {
ci = ar->i_ci;
func = s2v(ci->func);
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, func);
api_incr_top(L);
}
if (strchr(what, 'L'))
collectvalidlines(L, cl);
lua_unlock(L);
return status;
}
/*
** {======================================================
** Symbolic Execution
** =======================================================
*/
static const char *getobjname (const Proto *p, int lastpc, int reg,
const char **name);
/*
** Find a "name" for the constant 'c'.
*/
static void kname (const Proto *p, int c, const char **name) {
TValue *kvalue = &p->k[c];
*name = (ttisstring(kvalue)) ? svalue(kvalue) : "?";
}
/*
** Find a "name" for the register 'c'.
*/
static void rname (const Proto *p, int pc, int c, const char **name) {
const char *what = getobjname(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);
}
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 (GET_OPCODE(p->code[lastpc]) == OP_MMBIN ||
GET_OPCODE(p->code[lastpc]) == OP_MMBINI ||
GET_OPCODE(p->code[lastpc]) == OP_MMBINK)
lastpc--;
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;
}
/*
** Check whether table being indexed by instruction 'i' is the
** environment '_ENV'
*/
static const char *gxf (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 an upvalue? */
name = upvalname(p, t);
else
getobjname(p, pc, t, &name);
return (name && strcmp(name, LUA_ENV) == 0) ? "global" : "field";
}
static const char *getobjname (const 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: {
int k = GETARG_C(i); /* key index */
kname(p, k, name);
return gxf(p, pc, i, 1);
}
case OP_GETTABLE: {
int k = GETARG_C(i); /* key index */
rname(p, pc, k, name);
return gxf(p, pc, 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 gxf(p, pc, i, 0);
}
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: {
rkname(p, pc, 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, CallInfo *ci,
const char **name) {
TMS tm = (TMS)0; /* (initial value avoids warnings) */
const 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:
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_SHL: case OP_SHR: {
int offset = GET_OPCODE(i) - OP_ADD; /* ORDER OP */
tm = cast(TMS, offset + 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: case OP_LE: case OP_LTI: case OP_LEI:
*name = "order"; /* '<=' can call '__lt', etc. */
return "metamethod";
case OP_SHRI: case OP_SHLI:
*name = "shift";
return "metamethod";
case OP_CLOSE: case OP_RETURN:
*name = "close";
return "metamethod";
default:
return NULL; /* cannot find a reasonable name */
}
*name = getstr(G(L)->tmname[tm]) + 2;
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) {
StkId base = ci->func + 1;
ptrdiff_t i = cast(StkId, o) - base;
return (0 <= i && i < (ci->top - base) && s2v(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(cast(StkId, o) - (ci->func + 1)), &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_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 (!tointegerns(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), 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, 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);
}
/*
** Check whether new instruction 'newpc' is in a different line from
** previous instruction 'oldpc'.
*/
static int changedline (const Proto *p, int oldpc, int newpc) {
while (oldpc++ < newpc) {
if (p->lineinfo[oldpc] != 0)
return (luaG_getfuncline(p, oldpc - 1) != luaG_getfuncline(p, newpc));
}
return 0; /* no line changes in the way */
}
int luaG_traceexec (lua_State *L, const Instruction *pc) {
CallInfo *ci = L->ci;
lu_byte mask = L->hookmask;
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 = (--L->hookcount == 0 && (mask & LUA_MASKCOUNT));
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) { /* called hook 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)))
L->top = ci->top; /* prepare top */
if (counthook)
luaD_hook(L, LUA_HOOKCOUNT, -1, 0, 0); /* call count hook */
if (mask & LUA_MASKLINE) {
const Proto *p = ci_func(ci)->p;
int npci = pcRel(pc, p);
if (npci == 0 || /* call linehook when enter a new function, */
pc <= L->oldpc || /* when jump back (loop), or when */
changedline(p, pcRel(L->oldpc, p), npci)) { /* enter new line */
int newline = luaG_getfuncline(p, npci);
luaD_hook(L, LUA_HOOKLINE, newline, 0, 0); /* call line hook */
}
L->oldpc = pc; /* '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->u.l.savedpc--; /* undo increment (resume will increment it again) */
ci->callstatus |= CIST_HOOKYIELD; /* mark that it yielded */
luaD_throw(L, LUA_YIELD);
}
return 1; /* keep 'trap' on */
}