Move debugging/introspection functionality to lj_debug.c.

1 files changed, 429 insertions, 0 deletions

diff --git a/src/lj_debug.c b/src/lj_debug.c
new file mode 100644
index 00000000..a5ffff74
--- /dev/null
+++ b/src/lj_debug.c
@@ -0,0 +1,429 @@
+/*
+** Debugging and introspection.
+** Copyright (C) 2005-2011 Mike Pall. See Copyright Notice in luajit.h
+*/
+
+#define lj_debug_c
+#define LUA_CORE
+
+#include "lj_obj.h"
+#include "lj_err.h"
+#include "lj_str.h"
+#include "lj_tab.h"
+#include "lj_state.h"
+#include "lj_frame.h"
+#include "lj_bc.h"
+
+/* -- Frames -------------------------------------------------------------- */
+
+/* Get frame corresponding to a level. */
+cTValue *lj_debug_frame(lua_State *L, int level, int *size)
+{
+  cTValue *frame, *nextframe, *bot = tvref(L->stack);
+  /* Traverse frames backwards. */
+  for (nextframe = frame = L->base-1; frame > bot; ) {
+    if (frame_gc(frame) == obj2gco(L))
+      level++;  /* Skip dummy frames. See lj_meta_call(). */
+    if (level-- == 0) {
+      *size = (int)(nextframe - frame);
+      return frame;  /* Level found. */
+    }
+    nextframe = frame;
+    if (frame_islua(frame)) {
+      frame = frame_prevl(frame);
+    } else {
+      if (frame_isvarg(frame))
+        level++;  /* Skip vararg pseudo-frame. */
+      frame = frame_prevd(frame);
+    }
+  }
+  *size = level;
+  return NULL;  /* Level not found. */
+}
+
+/* Invalid bytecode position. */
+#define NO_BCPOS        (~(BCPos)0)
+
+/* Return bytecode position for function/frame or NO_BCPOS. */
+static BCPos debug_framepc(lua_State *L, GCfunc *fn, cTValue *nextframe)
+{
+  const BCIns *ins;
+  lua_assert(fn->c.gct == ~LJ_TFUNC || fn->c.gct == ~LJ_TTHREAD);
+  if (!isluafunc(fn)) {  /* Cannot derive a PC for non-Lua functions. */
+    return NO_BCPOS;
+  } else if (nextframe == NULL) {  /* Lua function on top. */
+    void *cf = cframe_raw(L->cframe);
+    if (cf == NULL || (char *)cframe_pc(cf) == (char *)cframe_L(cf))
+      return NO_BCPOS;
+    ins = cframe_pc(cf);  /* Only happens during error/hook handling. */
+  } else {
+    if (frame_islua(nextframe)) {
+      ins = frame_pc(nextframe);
+    } else if (frame_iscont(nextframe)) {
+      ins = frame_contpc(nextframe);
+    } else {
+      /* Lua function below errfunc/gc/hook: find cframe to get the PC. */
+      void *cf = cframe_raw(L->cframe);
+      TValue *f = L->base-1;
+      if (cf == NULL)
+        return NO_BCPOS;
+      while (f > nextframe) {
+        if (frame_islua(f)) {
+          f = frame_prevl(f);
+        } else {
+          if (frame_isc(f))
+            cf = cframe_raw(cframe_prev(cf));
+          f = frame_prevd(f);
+        }
+      }
+      if (cframe_prev(cf))
+        cf = cframe_raw(cframe_prev(cf));
+      ins = cframe_pc(cf);
+    }
+  }
+  return proto_bcpos(funcproto(fn), ins) - 1;
+}
+
+/* -- Line numbers -------------------------------------------------------- */
+
+/* Get line number for a bytecode position. */
+BCLine LJ_FASTCALL lj_debug_line(GCproto *pt, BCPos pc)
+{
+  BCLine *lineinfo = proto_lineinfo(pt);
+  if (pc < pt->sizebc && lineinfo)
+    return lineinfo[pc];
+  return 0;
+}
+
+/* Get line number for function/frame. */
+static BCLine debug_frameline(lua_State *L, GCfunc *fn, cTValue *nextframe)
+{
+  BCPos pc = debug_framepc(L, fn, nextframe);
+  if (pc != NO_BCPOS) {
+    GCproto *pt = funcproto(fn);
+    lua_assert(pc < pt->sizebc);
+    return lj_debug_line(pt, pc);
+  }
+  return -1;
+}
+
+/* -- Variable names ------------------------------------------------------ */
+
+/* Get name of a local variable from slot number and PC. */
+static const char *debug_varname(const GCproto *pt, BCPos pc, BCReg slot)
+{
+  MSize i;
+  VarInfo *vi = proto_varinfo(pt);
+  for (i = 0; i < pt->sizevarinfo && vi[i].startpc <= pc; i++)
+    if (pc < vi[i].endpc && slot-- == 0)
+      return strdata(gco2str(gcref(vi[i].name)));
+  return NULL;
+}
+
+/* Get name of local variable from 1-based slot number and function/frame. */
+static TValue *debug_localname(lua_State *L, const lua_Debug *ar,
+                               const char **name, BCReg slot1)
+{
+  uint32_t offset = (uint32_t)ar->i_ci & 0xffff;
+  uint32_t size = (uint32_t)ar->i_ci >> 16;
+  TValue *frame = tvref(L->stack) + offset;
+  TValue *nextframe = size ? frame + size : NULL;
+  GCfunc *fn = frame_func(frame);
+  BCPos pc = debug_framepc(L, fn, nextframe);
+  if (pc != NO_BCPOS &&
+      (*name = debug_varname(funcproto(fn), pc, slot1-1)) != NULL)
+    ;
+  else if (slot1 > 0 && frame + slot1 < (nextframe ? nextframe : L->top))
+    *name = "(*temporary)";
+  else
+    *name = NULL;
+  return frame+slot1;
+}
+
+/* Get name of upvalue. */
+const char *lj_debug_uvname(cTValue *o, uint32_t idx, TValue **tvp)
+{
+  if (tvisfunc(o)) {
+    GCfunc *fn = funcV(o);
+    if (isluafunc(fn)) {
+      GCproto *pt = funcproto(fn);
+      if (idx < pt->sizeuv) {
+        *tvp = uvval(&gcref(fn->l.uvptr[idx])->uv);
+        return strdata(proto_uvname(pt, idx));
+      }
+    } else {
+      if (idx < fn->c.nupvalues) {
+        *tvp = &fn->c.upvalue[idx];
+        return "";
+      }
+    }
+  }
+  return NULL;
+}
+
+/* Deduce name of an object from slot number and PC. */
+const char *lj_debug_slotname(GCproto *pt, const BCIns *ip, BCReg slot,
+                              const char **name)
+{
+  const char *lname;
+restart:
+  lname = debug_varname(pt, proto_bcpos(pt, ip), slot);
+  if (lname != NULL) { *name = lname; return "local"; }
+  while (--ip > proto_bc(pt)) {
+    BCIns ins = *ip;
+    BCOp op = bc_op(ins);
+    BCReg ra = bc_a(ins);
+    if (bcmode_a(op) == BCMbase) {
+      if (slot >= ra && (op != BC_KNIL || slot <= bc_d(ins)))
+        return NULL;
+    } else if (bcmode_a(op) == BCMdst && ra == slot) {
+      switch (bc_op(ins)) {
+      case BC_MOV:
+        if (ra == slot) { slot = bc_d(ins); goto restart; }
+        break;
+      case BC_GGET:
+        *name = strdata(gco2str(proto_kgc(pt, ~(ptrdiff_t)bc_d(ins))));
+        return "global";
+      case BC_TGETS:
+        *name = strdata(gco2str(proto_kgc(pt, ~(ptrdiff_t)bc_c(ins))));
+        if (ip > proto_bc(pt)) {
+          BCIns insp = ip[-1];
+          if (bc_op(insp) == BC_MOV && bc_a(insp) == ra+1 &&
+              bc_d(insp) == bc_b(ins))
+            return "method";
+        }
+        return "field";
+      case BC_UGET:
+        *name = strdata(proto_uvname(pt, bc_d(ins)));
+        return "upvalue";
+      default:
+        return NULL;
+      }
+    }
+  }
+  return NULL;
+}
+
+/* Deduce function name from caller of a frame. */
+const char *lj_debug_funcname(lua_State *L, TValue *frame, const char **name)
+{
+  TValue *pframe;
+  GCfunc *fn;
+  BCPos pc;
+  if (frame_isvarg(frame))
+    frame = frame_prevd(frame);
+  pframe = frame_prev(frame);
+  fn = frame_func(pframe);
+  pc = debug_framepc(L, fn, frame);
+  if (pc != NO_BCPOS) {
+    GCproto *pt = funcproto(fn);
+    const BCIns *ip = &proto_bc(pt)[check_exp(pc < pt->sizebc, pc)];
+    MMS mm = bcmode_mm(bc_op(*ip));
+    if (mm == MM_call) {
+      BCReg slot = bc_a(*ip);
+      if (bc_op(*ip) == BC_ITERC) slot -= 3;
+      return lj_debug_slotname(pt, ip, slot, name);
+    } else if (mm != MM__MAX) {
+      *name = strdata(mmname_str(G(L), mm));
+      return "metamethod";
+    }
+  }
+  return NULL;
+}
+
+/* -- Source code locations ----------------------------------------------- */
+
+/* Generate shortened source name. */
+void lj_debug_shortname(char *out, const char *src)
+{
+  if (*src == '=') {
+    strncpy(out, src+1, LUA_IDSIZE);  /* remove first char */
+    out[LUA_IDSIZE-1] = '\0';  /* ensures null termination */
+  } else if (*src == '@') { /* out = "source", or "...source" */
+    size_t l = strlen(++src);  /* skip the `@' */
+    if (l >= LUA_IDSIZE) {
+      src += l-(LUA_IDSIZE-4);  /* get last part of file name */
+      strcpy(out, "...");
+      out += 3;
+    }
+    strcpy(out, src);
+  } else {  /* out = [string "string"] */
+    size_t len; /* Length, up to first control char. */
+    for (len = 0; len < LUA_IDSIZE-12; len++)
+      if (((const unsigned char *)src)[len] < ' ') break;
+    strcpy(out, "[string \""); out += 9;
+    if (src[len] != '\0') {  /* must truncate? */
+      if (len > LUA_IDSIZE-15) len = LUA_IDSIZE-15;
+      strncpy(out, src, len); out += len;
+      strcpy(out, "..."); out += 3;
+    } else {
+      strcpy(out, src); out += len;
+    }
+    strcpy(out, "\"]");
+  }
+}
+
+/* Add current location of a frame to error message. */
+void lj_debug_addloc(lua_State *L, const char *msg,
+                     cTValue *frame, cTValue *nextframe)
+{
+  if (frame) {
+    GCfunc *fn = frame_func(frame);
+    if (isluafunc(fn)) {
+      BCLine line = debug_frameline(L, fn, nextframe);
+      if (line >= 0) {
+        char buf[LUA_IDSIZE];
+        lj_debug_shortname(buf, strdata(proto_chunkname(funcproto(fn))));
+        lj_str_pushf(L, "%s:%d: %s", buf, line, msg);
+        return;
+      }
+    }
+  }
+  lj_str_pushf(L, "%s", msg);
+}
+
+/* Push location string for a bytecode position to Lua stack. */
+void lj_debug_pushloc(lua_State *L, GCproto *pt, BCPos pc)
+{
+  GCstr *name = proto_chunkname(pt);
+  if (name) {
+    const char *s = strdata(name);
+    MSize i, len = name->len;
+    BCLine line = lj_debug_line(pt, pc);
+    if (*s == '@') {
+      s++; len--;
+      for (i = len; i > 0; i--)
+        if (s[i] == '/' || s[i] == '\\') {
+          s += i+1;
+          break;
+        }
+      lj_str_pushf(L, "%s:%d", s, line);
+    } else if (len > 40) {
+      lj_str_pushf(L, "%p:%d", pt, line);
+    } else if (*s == '=') {
+      lj_str_pushf(L, "%s:%d", s+1, line);
+    } else {
+      lj_str_pushf(L, "\"%s\":%d", s, line);
+    }
+  } else {
+    lj_str_pushf(L, "%p:%u", pt, pc);
+  }
+}
+
+/* -- Public debug API ---------------------------------------------------- */
+
+/* lua_getupvalue() and lua_setupvalue() are in lj_api.c. */
+
+LUA_API const char *lua_getlocal(lua_State *L, const lua_Debug *ar, int n)
+{
+  const char *name;
+  TValue *o = debug_localname(L, ar, &name, (BCReg)n);
+  if (name) {
+    copyTV(L, L->top, o);
+    incr_top(L);
+  }
+  return name;
+}
+
+LUA_API const char *lua_setlocal(lua_State *L, const lua_Debug *ar, int n)
+{
+  const char *name;
+  TValue *o = debug_localname(L, ar, &name, (BCReg)n);
+  if (name)
+    copyTV(L, o, L->top-1);
+  L->top--;
+  return name;
+}
+
+LUA_API int lua_getinfo(lua_State *L, const char *what, lua_Debug *ar)
+{
+  int status = 1;
+  TValue *frame = NULL;
+  TValue *nextframe = NULL;
+  GCfunc *fn;
+  if (*what == '>') {
+    TValue *func = L->top - 1;
+    api_check(L, tvisfunc(func));
+    fn = funcV(func);
+    L->top--;
+    what++;
+  } else {
+    uint32_t offset = (uint32_t)ar->i_ci & 0xffff;
+    uint32_t size = (uint32_t)ar->i_ci >> 16;
+    lua_assert(offset != 0);
+    frame = tvref(L->stack) + offset;
+    if (size) nextframe = frame + size;
+    lua_assert(frame <= tvref(L->maxstack) &&
+               (!nextframe || nextframe <= tvref(L->maxstack)));
+    fn = frame_func(frame);
+    lua_assert(fn->c.gct == ~LJ_TFUNC);
+  }
+  for (; *what; what++) {
+    switch (*what) {
+    case 'S':
+      if (isluafunc(fn)) {
+        GCproto *pt = funcproto(fn);
+        ar->source = strdata(proto_chunkname(pt));
+        ar->linedefined = (int)proto_line(pt, 0);
+        ar->lastlinedefined = (int)pt->lastlinedefined;
+        ar->what = ar->linedefined ? "Lua" : "main";
+      } else {
+        ar->source = "=[C]";
+        ar->linedefined = -1;
+        ar->lastlinedefined = -1;
+        ar->what = "C";
+      }
+      lj_debug_shortname(ar->short_src, ar->source);
+      break;
+    case 'l':
+      ar->currentline = frame ? debug_frameline(L, fn, nextframe) : -1;
+      break;
+    case 'u':
+      ar->nups = fn->c.nupvalues;
+      break;
+    case 'n':
+      ar->namewhat = frame ? lj_debug_funcname(L, frame, &ar->name) : NULL;
+      if (ar->namewhat == NULL) {
+        ar->namewhat = "";
+        ar->name = NULL;
+      }
+      break;
+    case 'f':
+      setfuncV(L, L->top, fn);
+      incr_top(L);
+      break;
+    case 'L':
+      if (isluafunc(fn)) {
+        GCtab *t = lj_tab_new(L, 0, 0);
+        GCproto *pt = funcproto(fn);
+        BCLine *lineinfo = proto_lineinfo(pt);
+        MSize i, szl = pt->sizebc;
+        for (i = 1; i < szl; i++)
+          setboolV(lj_tab_setint(L, t, lineinfo[i]), 1);
+        settabV(L, L->top, t);
+      } else {
+        setnilV(L->top);
+      }
+      incr_top(L);
+      break;
+    default:
+      status = 0;  /* Bad option. */
+      break;
+    }
+  }
+  return status;
+}
+
+LUA_API int lua_getstack(lua_State *L, int level, lua_Debug *ar)
+{
+  int size;
+  cTValue *frame = lj_debug_frame(L, level, &size);
+  if (frame) {
+    ar->i_ci = (size << 16) + (int)(frame - tvref(L->stack));
+    return 1;
+  } else {
+    ar->i_ci = level - size;
+    return 0;
+  }
+}
+