lua/ldebug.c
Roberto Ierusalimschy b0f2b288a6 new scheme for debug info about tail calls: no more 'fake' stack entries,
but stack entry knows whether it was tail called
2009-11-25 13:27:51 -02:00

481 lines
12 KiB
C

/*
** $Id: ldebug.c,v 2.57 2009/10/13 19:07:40 roberto Exp roberto $
** Debug Interface
** See Copyright Notice in lua.h
*/
#include <stdarg.h>
#include <stddef.h>
#include <string.h>
#define ldebug_c
#define LUA_CORE
#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"
static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
static int currentpc (CallInfo *ci) {
if (!isLua(ci)) return -1; /* function is not a Lua function? */
return pcRel(ci->u.l.savedpc, ci_func(ci)->l.p);
}
static int currentline (CallInfo *ci) {
int pc = currentpc(ci);
if (pc < 0)
return -1; /* only active lua functions have current-line information */
else
return getfuncline(ci_func(ci)->l.p, pc);
}
/*
** this function can be called asynchronous (e.g. during a signal)
*/
LUA_API int 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->oldpc = NULL;
L->hook = func;
L->basehookcount = count;
resethookcount(L);
L->hookmask = cast_byte(mask);
return 1;
}
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 *findlocal (lua_State *L, CallInfo *ci, int n,
StkId *pos) {
const char *name = NULL;
StkId base;
if (isLua(ci)) {
base = ci->u.l.base;
name = luaF_getlocalname(ci_func(ci)->l.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) {
StkId pos;
const char *name = findlocal(L, ar->i_ci, n, &pos);
lua_lock(L);
if (name) {
setobj2s(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;
const char *name = findlocal(L, ar->i_ci, n, &pos);
lua_lock(L);
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 (cl->c.isC) {
ar->source = "=[C]";
ar->linedefined = -1;
ar->lastlinedefined = -1;
ar->what = "C";
}
else {
ar->source = getstr(cl->l.p->source);
ar->linedefined = cl->l.p->linedefined;
ar->lastlinedefined = cl->l.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 (f == NULL || f->c.isC) {
setnilvalue(L->top);
incr_top(L);
}
else {
int i;
int *lineinfo = f->l.p->lineinfo;
Table *t = luaH_new(L);
sethvalue(L, L->top, t);
incr_top(L);
for (i=0; i<f->l.p->sizelineinfo; i++)
setbvalue(luaH_setint(L, t, lineinfo[i]), 1);
}
}
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) ? currentline(ci) : -1;
break;
}
case 'u': {
ar->nups = f->c.nupvalues;
break;
}
case 't': {
ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
break;
}
case 'n': {
ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : NULL;
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 *f = NULL;
CallInfo *ci = NULL;
lua_lock(L);
if (*what == '>') {
StkId func = L->top - 1;
luai_apicheck(L, ttisfunction(func));
what++; /* skip the '>' */
f = clvalue(func);
L->top--; /* pop function */
}
else {
ci = ar->i_ci;
lua_assert(ttisfunction(ci->func));
f = clvalue(ci->func);
}
status = auxgetinfo(L, what, ar, f, ci);
if (strchr(what, 'f')) {
setclvalue(L, L->top, f);
incr_top(L);
}
if (strchr(what, 'L'))
collectvalidlines(L, f);
lua_unlock(L);
return status;
}
/*
** {======================================================
** Symbolic Execution
** =======================================================
*/
static const char *kname (Proto *p, int c) {
if (ISK(c) && ttisstring(&p->k[INDEXK(c)]))
return svalue(&p->k[INDEXK(c)]);
else
return "?";
}
static const char *getobjname (lua_State *L, CallInfo *ci, int reg,
const char **name) {
Proto *p;
int lastpc, pc;
const char *what = NULL;
lua_assert(isLua(ci));
p = ci_func(ci)->l.p;
lastpc = currentpc(ci);
*name = luaF_getlocalname(p, reg + 1, lastpc);
if (*name) /* is a local? */
return "local";
/* else try symbolic execution */
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_GETGLOBAL: {
if (reg == a) {
int g = GETARG_Bx(i);
if (g != 0) g--;
else g = GETARG_Ax(p->code[++pc]);
lua_assert(ttisstring(&p->k[g]));
*name = svalue(&p->k[g]);
what = "global";
}
break;
}
case OP_MOVE: {
if (reg == a) {
int b = GETARG_B(i); /* move from 'b' to 'a' */
if (b < a)
what = getobjname(L, ci, b, name); /* get name for 'b' */
else what = NULL;
}
break;
}
case OP_GETTABLE: {
if (reg == a) {
int k = GETARG_C(i); /* key index */
*name = kname(p, k);
what = "field";
}
break;
}
case OP_GETUPVAL: {
if (reg == a) {
int u = GETARG_B(i); /* upvalue index */
TString *tn = p->upvalues[u].name;
*name = tn ? getstr(tn) : "?";
what = "upvalue";
}
break;
}
case OP_LOADNIL: {
int b = GETARG_B(i); /* move from 'b' to 'a' */
if (a <= reg && reg <= b) /* set registers from 'a' to 'b' */
what = NULL;
break;
}
case OP_SELF: {
if (reg == a) {
int k = GETARG_C(i); /* key index */
*name = kname(p, k);
what = "method";
}
break;
}
case OP_TFORCALL: {
if (reg >= a + 2) what = NULL; /* affect all regs above its base */
break;
}
case OP_CALL:
case OP_TAILCALL: {
if (reg >= a) what = NULL; /* affect all registers above base */
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)
pc += b; /* do the jump */
break;
}
default:
if (testAMode(op) && reg == a) what = NULL;
break;
}
}
return what;
}
static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
TMS tm = 0;
Instruction i;
if ((ci->callstatus & CIST_TAIL) || !isLua(ci->previous))
return NULL; /* calling function is not Lua (or is unknown) */
ci = ci->previous; /* calling function */
i = ci_func(ci)->l.p->code[currentpc(ci)];
if (GET_OPCODE(i) == OP_EXTRAARG) /* extra argument? */
i = ci_func(ci)->l.p->code[currentpc(ci) - 1]; /* get 'real' instruction */
switch (GET_OPCODE(i)) {
case OP_CALL:
case OP_TAILCALL:
case OP_TFORLOOP:
return getobjname(L, ci, GETARG_A(i), name);
case OP_GETGLOBAL:
case OP_SELF:
case OP_GETTABLE: tm = TM_INDEX; break;
case OP_SETGLOBAL:
case OP_SETTABLE: tm = TM_NEWINDEX; break;
case OP_EQ: tm = TM_EQ; break;
case OP_ADD: tm = TM_ADD; break;
case OP_SUB: tm = TM_SUB; break;
case OP_MUL: tm = TM_MUL; break;
case OP_DIV: tm = TM_DIV; break;
case OP_MOD: tm = TM_MOD; break;
case OP_POW: tm = TM_POW; break;
case OP_UNM: tm = TM_UNM; break;
case OP_LEN: tm = TM_LEN; break;
case OP_LT: tm = TM_LT; break;
case OP_LE: tm = TM_LE; break;
case OP_CONCAT: tm = TM_CONCAT; break;
default:
return NULL; /* else no useful name can be found */
}
*name = getstr(G(L)->tmname[tm]);
return "metamethod";
}
/* }====================================================== */
/* only ANSI way to check whether a pointer points to an array */
static int isinstack (CallInfo *ci, const TValue *o) {
StkId p;
for (p = ci->u.l.base; p < ci->top; p++)
if (o == p) return 1;
return 0;
}
void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
CallInfo *ci = L->ci;
const char *name = NULL;
const char *t = luaT_typenames[ttype(o)];
const char *kind = (isLua(ci) && isinstack(ci, o)) ?
getobjname(L, ci, cast_int(o - ci->u.l.base), &name) :
NULL;
if (kind)
luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
op, kind, name, t);
else
luaG_runerror(L, "attempt to %s a %s value", op, t);
}
void luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
lua_assert(!ttisstring(p1) && !ttisnumber(p2));
luaG_typeerror(L, p1, "concatenate");
}
void luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
TValue temp;
if (luaV_tonumber(p1, &temp) == NULL)
p2 = p1; /* first operand is wrong */
luaG_typeerror(L, p2, "perform arithmetic on");
}
int luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
const char *t1 = luaT_typenames[ttype(p1)];
const char *t2 = luaT_typenames[ttype(p2)];
if (t1[2] == t2[2])
luaG_runerror(L, "attempt to compare two %s values", t1);
else
luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
return 0;
}
static void addinfo (lua_State *L, const char *msg) {
CallInfo *ci = L->ci;
if (isLua(ci)) { /* is Lua code? */
char buff[LUA_IDSIZE]; /* add file:line information */
int line = currentline(ci);
luaO_chunkid(buff, getstr(ci_func(ci)->l.p->source), LUA_IDSIZE);
luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
}
}
void luaG_errormsg (lua_State *L) {
if (L->errfunc != 0) { /* is there an error handling function? */
StkId errfunc = restorestack(L, L->errfunc);
if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
setobjs2s(L, L->top, L->top - 1); /* move argument */
setobjs2s(L, L->top - 1, errfunc); /* push function */
incr_top(L);
luaD_call(L, L->top - 2, 1, 0); /* call it */
}
luaD_throw(L, LUA_ERRRUN);
}
void luaG_runerror (lua_State *L, const char *fmt, ...) {
va_list argp;
va_start(argp, fmt);
addinfo(L, luaO_pushvfstring(L, fmt, argp));
va_end(argp);
luaG_errormsg(L);
}