1 files changed, 641 insertions, 0 deletions

diff --git a/erts/emulator/hipe/hipe_mode_switch.c b/erts/emulator/hipe/hipe_mode_switch.c
new file mode 100644
index 0000000000..e5de244d25
--- /dev/null
+++ b/erts/emulator/hipe/hipe_mode_switch.c
@@ -0,0 +1,641 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2001-2009. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ */
+/* $Id$
+ * hipe_mode_switch.c
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "sys.h"
+#include "erl_vm.h"
+#include "global.h"
+#include "erl_process.h"
+#include "beam_load.h"	/* which includes beam_opcodes.h */
+#include "beam_catches.h"
+#include "hipe_mode_switch.h"
+#include "bif.h"
+#include "error.h"
+#include "hipe_stack.h"
+#include "hipe_bif0.h"	/* hipe_mfa_info_table_init() */
+
+/*
+ * Internal debug support.
+ * #define HIPE_DEBUG to the desired debug level:
+ *	0	no checks
+ *	1	check PCB consistency at mode-switches
+ *	2	log commands and results at mode-switches
+ *	3	log commands, results, and PCB contents at mode-switches
+ *
+ * TODO: check PCB consistency at native BIF calls
+ */
+int hipe_modeswitch_debug = 0;
+
+#define HIPE_DEBUG 0
+
+#if HIPE_DEBUG > 1	/* include DPRINTF() logging */
+
+#define DPRINTF(fmt, args...) \
+do { \
+    if (hipe_modeswitch_debug > 0) { \
+	printf("%s, line %u: " fmt "\r\n", __FUNCTION__, __LINE__ , ##args); \
+	fflush(stdout); \
+    } \
+} while (0)
+
+static const char *code_str(unsigned code)
+{
+    static const char *cmd_str[] = {
+	"call from beam",
+	"return from beam",
+	"throw from beam",
+	"resume from beam",
+	"return to beam",
+	"call to beam",
+	"throw to beam",
+	"suspend to beam",
+	"wait from native",
+	"wait_timeout from native",
+	"trap from native",
+	"call closure from beam",
+	"call closure to beam",
+    };
+    unsigned cmd = code & 0xFF;
+
+    if (cmd < (sizeof(cmd_str)/sizeof(cmd_str[0])))
+	return cmd_str[cmd];
+    else
+	return "???";
+}
+
+#else	/* HIPE_DEBUG > 1 */
+
+#define DPRINTF(fmt, args...)	do{}while(0)
+
+#endif	/* HIPE_DEBUG > 1 */
+
+#if HIPE_DEBUG > 0	/* include HIPE_ASSERT and PCB checking */
+
+static void __noreturn
+hipe_abort(const char *expr, const char *file, unsigned line)
+{
+    erl_exit(1, "ASSERTION FAILED, file %s, line %u: %s\r\n", file, line, expr);
+}
+
+#define HIPE_ASSERT3(expr, file, line) \
+do { \
+    if (!(expr)) \
+	hipe_abort(#expr, file, line); \
+} while (0)
+#define HIPE_ASSERT(expr)	HIPE_ASSERT3(expr, __FILE__, __LINE__)
+
+void hipe_check_pcb(Process *p, const char *file, unsigned line)
+{
+#if HIPE_DEBUG > 2
+    if (hipe_modeswitch_debug > 0) {
+        printf("%s, line %u: p %p = {htop %p, stop %p, nstack %p, nsp %p, nstend %p}\r\n", file, line, p, p->htop, p->stop, p->hipe.nstack, p->hipe.nsp, p->hipe.nstend);
+    }
+#endif
+    HIPE_ASSERT3(p != NULL, file, line);
+    HIPE_ASSERT3(p->htop <= p->stop, file, line);
+    HIPE_ASSERT3(p->hipe.nstack <= p->hipe.nstend, file, line);
+    HIPE_ASSERT3(p->hipe.nsp >= p->hipe.nstack, file, line);
+    HIPE_ASSERT3(p->hipe.nsp <= p->hipe.nstend, file, line);
+}
+#define HIPE_CHECK_PCB(P)	hipe_check_pcb((P), __FILE__, __LINE__)
+
+#else	/* HIPE_DEBUG > 0 */
+
+#define HIPE_ASSERT(expr)	do{}while(0)
+#define HIPE_CHECK_PCB(P)	do{}while(0)
+
+#endif	/* HIPE_DEBUG > 0 */
+
+/* ensure that at least nwords words are available on the native stack */
+static void hipe_check_nstack(Process *p, unsigned nwords);
+
+#if defined(__sparc__)
+#include "hipe_sparc_glue.h"
+#elif defined(__i386__)
+#include "hipe_x86_glue.h"
+#elif defined(__x86_64__)
+#include "hipe_amd64_glue.h"
+#elif defined(__powerpc__) || defined(__ppc__) || defined(__powerpc64__)
+#include "hipe_ppc_glue.h"
+#elif defined(__arm__)
+#include "hipe_arm_glue.h"
+#endif
+
+#define BeamOpCode(Op)		((Uint)BeamOp(Op))
+
+Uint hipe_beam_pc_return[1];	/* needed in hipe_debug.c */
+Uint hipe_beam_pc_throw[1];	/* needed in hipe_debug.c */
+Uint hipe_beam_pc_resume[1];	/* needed by hipe_set_timeout() */
+static Eterm hipe_beam_catch_throw;
+
+void hipe_mode_switch_init(void)
+{
+    hipe_arch_glue_init();
+
+    hipe_beam_pc_return[0] = BeamOpCode(op_hipe_trap_return);
+    hipe_beam_pc_throw[0] = BeamOpCode(op_hipe_trap_throw);
+    hipe_beam_pc_resume[0] = BeamOpCode(op_hipe_trap_resume);
+
+    hipe_beam_catch_throw =
+	make_catch(beam_catches_cons(hipe_beam_pc_throw, BEAM_CATCHES_NIL));
+
+    hipe_mfa_info_table_init();
+}
+
+void hipe_set_call_trap(Uint *bfun, void *nfun, int is_closure)
+{
+    HIPE_ASSERT(bfun[-5] == BeamOpCode(op_i_func_info_IaaI));
+    bfun[0] =
+	is_closure
+	? BeamOpCode(op_hipe_trap_call_closure)
+	: BeamOpCode(op_hipe_trap_call);
+    bfun[-4] = (Uint)nfun;
+}
+
+static __inline__ void
+hipe_push_beam_trap_frame(Process *p, Eterm reg[], unsigned arity)
+{
+    /* ensure that at least 2 words are available on the BEAM stack */
+    if ((p->stop - 2) < p->htop) {
+	DPRINTF("calling gc to increase BEAM stack size");
+	p->fcalls -= erts_garbage_collect(p, 2, reg, arity);
+    }
+    p->stop -= 2;
+    p->stop[1] = hipe_beam_catch_throw;
+    p->stop[0] = make_cp(p->cp);
+    ++p->catches;
+    p->cp = hipe_beam_pc_return;
+}
+
+static __inline__ void hipe_pop_beam_trap_frame(Process *p)
+{
+    p->cp = cp_val(p->stop[0]);
+    --p->catches;
+    p->stop += 2;
+}
+
+Process *hipe_mode_switch(Process *p, unsigned cmd, Eterm reg[])
+{
+    unsigned result;
+#if NR_ARG_REGS > 5
+    /* When NR_ARG_REGS > 5, we need to protect the process' input
+       reduction count (which BEAM stores in def_arg_reg[5]) from
+       being clobbered by the arch glue code. */
+    Eterm reds_in = p->def_arg_reg[5];
+#endif
+#if NR_ARG_REGS > 4
+    Eterm o_reds = p->def_arg_reg[4];
+#endif
+
+    p->i = NULL;
+
+    DPRINTF("cmd == %#x (%s)", cmd, code_str(cmd));
+    HIPE_CHECK_PCB(p);
+    p->arity = 0;
+    switch (cmd & 0xFF) {
+      case HIPE_MODE_SWITCH_CMD_CALL: {
+	  /* BEAM calls a native code function */
+	  unsigned arity = cmd >> 8;
+
+	  /* p->hipe.ncallee set in beam_emu */
+	  if (p->cp == hipe_beam_pc_return) {
+	    /* Native called BEAM, which now tailcalls native. */
+	    hipe_pop_beam_trap_frame(p);
+	    result = hipe_tailcall_to_native(p, arity, reg);
+	    break;
+	  }
+	  DPRINTF("calling %#lx/%u", (long)p->hipe.ncallee, arity);
+	  result = hipe_call_to_native(p, arity, reg);
+	  break;
+      }
+      case HIPE_MODE_SWITCH_CMD_CALL_CLOSURE: {
+	  /* BEAM calls a native code closure */
+	  unsigned arity = cmd >> 8; /* #formals + #fvs (closure not counted) */
+	  Eterm fun;
+	  ErlFunThing *funp;
+
+	  /* drop the fvs, move the closure, correct arity */
+	  fun = reg[arity];
+	  HIPE_ASSERT(is_fun(fun));
+	  funp = (ErlFunThing*)fun_val(fun);
+	  HIPE_ASSERT(funp->num_free <= arity);
+	  arity -= funp->num_free;	/* arity == #formals */
+	  reg[arity] = fun;
+	  ++arity;	/* correct for having added the closure */
+	  /* HIPE_ASSERT(p->hipe.ncallee == (void(*)(void))funp->native_address); */
+
+	  /* just like a normal call from now on */
+
+	  /* p->hipe.ncallee set in beam_emu */
+	  if (p->cp == hipe_beam_pc_return) {
+	      /* Native called BEAM, which now tailcalls native. */
+	      hipe_pop_beam_trap_frame(p);
+	      result = hipe_tailcall_to_native(p, arity, reg);
+	      break;
+	  }
+	  DPRINTF("calling %#lx/%u", (long)p->hipe.ncallee, arity);
+	  result = hipe_call_to_native(p, arity, reg);
+	  break;
+      }
+      case HIPE_MODE_SWITCH_CMD_THROW: {
+	  /* BEAM just executed hipe_beam_pc_throw[] */
+	  /* Native called BEAM, which now throws an exception back to native. */
+	  DPRINTF("beam throws freason %#lx fvalue %#lx", p->freason, p->fvalue);
+	  hipe_pop_beam_trap_frame(p);
+      do_throw_to_native:
+	  p->def_arg_reg[0] = exception_tag[GET_EXC_CLASS(p->freason)];
+	  hipe_find_handler(p);
+	  result = hipe_throw_to_native(p);
+	  break;
+      }
+      case HIPE_MODE_SWITCH_CMD_RETURN: {
+	  /* BEAM just executed hipe_beam_pc_return[] */
+	  /* Native called BEAM, which now returns back to native. */
+	  /* pop trap frame off estack */
+	  hipe_pop_beam_trap_frame(p);
+	  p->def_arg_reg[0] = reg[0];
+	  result = hipe_return_to_native(p);
+	  break;
+      }
+    do_resume:
+      case HIPE_MODE_SWITCH_CMD_RESUME: {
+	  /* BEAM just executed hipe_beam_pc_resume[] */
+	  /* BEAM called native, which suspended. */
+	  if (p->flags & F_TIMO) {
+	      /* XXX: The process will immediately execute 'clear_timeout',
+		 repeating these two statements. Remove them? */
+	      p->flags &= ~F_TIMO;
+	      JOIN_MESSAGE(p);
+	      p->def_arg_reg[0] = 0;	/* make_small(0)? */
+	  } else
+	      p->def_arg_reg[0] = 1;	/* make_small(1)? */
+	  result = hipe_return_to_native(p);
+	  break;
+      }
+      default:
+	erl_exit(1, "hipe_mode_switch: cmd %#x\r\n", cmd);
+    }
+ do_return_from_native:
+    DPRINTF("result == %#x (%s)", result, code_str(result));
+    HIPE_CHECK_PCB(p);
+    switch (result) {
+      case HIPE_MODE_SWITCH_RES_RETURN: {
+	  hipe_return_from_native(p);
+	  reg[0] = p->def_arg_reg[0];
+	  DPRINTF("returning with r(0) == %#lx", reg[0]);
+	  break;
+      }
+      case HIPE_MODE_SWITCH_RES_THROW: {
+	  DPRINTF("native throws freason %#lx fvalue %#lx", p->freason, p->fvalue);
+	  hipe_throw_from_native(p);
+	  break;
+      }
+      case HIPE_MODE_SWITCH_RES_TRAP: {
+	  /*
+	   * Native code called a BIF, which "failed" with a TRAP to BEAM.
+	   * Prior to returning, the BIF stored (see BIF_TRAP<N>):
+
+	   * the callee's address in p->def_arg_reg[3]
+	   * the callee's parameters in p->def_arg_reg[0..2]
+	   * the callee's arity in p->arity (for BEAM gc purposes)
+	   *
+	   * We need to remove the BIF's parameters from the native
+	   * stack: to this end hipe_${ARCH}_glue.S stores the BIF's
+	   * arity in p->hipe.narity.
+	   */
+	  unsigned int i, is_recursive, callee_arity;
+
+	  /* Save p->arity, then update it with the original BIF's arity.
+	     Get rid of any stacked parameters in that call. */
+	  /* XXX: hipe_call_from_native_is_recursive() copies data to
+	     reg[], which is useless in the TRAP case. Maybe write a
+	     specialised hipe_trap_from_native_is_recursive() later. */
+	  callee_arity = p->arity;
+	  p->arity = p->hipe.narity; /* caller's arity */
+	  is_recursive = hipe_call_from_native_is_recursive(p, reg);
+
+	  p->i = (Eterm *)(p->def_arg_reg[3]);
+	  p->arity = callee_arity;
+
+	  for (i = 0; i < p->arity; ++i)
+	      reg[i] = p->def_arg_reg[i];
+
+	  if (is_recursive)
+	      hipe_push_beam_trap_frame(p, reg, p->arity);
+
+	  result = HIPE_MODE_SWITCH_RES_CALL;
+	  break;
+      }
+      case HIPE_MODE_SWITCH_RES_CALL: {
+	  /* Native code calls or tailcalls BEAM.
+	   *
+	   * p->i is the callee's BEAM code
+	   * p->arity is the callee's arity
+	   * p->def_arg_reg[] contains the register parameters
+	   * p->hipe.nsp[] contains the stacked parameters
+	   */
+	  if (hipe_call_from_native_is_recursive(p, reg)) {
+	      /* BEAM called native, which now calls BEAM */
+	      hipe_push_beam_trap_frame(p, reg, p->arity);
+	  }
+	  break;
+      }
+      case HIPE_MODE_SWITCH_RES_CALL_CLOSURE: {
+	  /* Native code calls or tailcalls a closure in BEAM
+	   *
+	   * In native code a call to a closure of arity n looks like
+	   * F(A1, ..., AN, Closure),
+	   * The BEAM code for a closure expects to get:
+	   * F(A1, ..., AN, FV1, ..., FVM, Closure)
+	   *  (Where Ai is argument i and FVj is free variable j)
+	   *
+	   * p->hipe.closure contains the closure
+	   * p->def_arg_reg[] contains the register parameters
+	   * p->hipe.nsp[] contains the stacked parameters
+	   */
+	  ErlFunThing *closure;
+	  unsigned num_free, arity, i, is_recursive;
+
+	  HIPE_ASSERT(is_fun(p->hipe.closure));
+	  closure = (ErlFunThing*)fun_val(p->hipe.closure);
+	  num_free = closure->num_free;
+	  arity = closure->fe->arity;
+
+	  /* Store the arity in p->arity for the stack popping. */
+	  /* Note: we already have the closure so only need to move arity
+	     values to reg[]. However, there are arity+1 parameters in the
+	     native code state that need to be removed. */
+	  p->arity = arity+1; /* +1 for the closure */
+
+	  /* Get parameters, don't do GC just yet. */
+	  is_recursive = hipe_call_from_native_is_recursive(p, reg);
+
+	  if ((Sint)closure->fe->address[-1] < 0) {
+	      /* Unloaded. Let beam_emu.c:call_fun() deal with it. */
+	      result = HIPE_MODE_SWITCH_RES_CALL_CLOSURE;
+	  } else {
+	      /* The BEAM code is present. Prepare to call it. */
+
+	      /* Append the free vars after the actual parameters. */
+	      for (i = 0; i < num_free; ++i)
+		  reg[arity+i] = closure->env[i];
+
+	      /* Update arity to reflect the new parameters. */
+	      arity += i;
+
+	      /* Make a call to the closure's BEAM code. */
+	      p->i = closure->fe->address;
+
+	      /* Change result code to the faster plain CALL type. */
+	      result = HIPE_MODE_SWITCH_RES_CALL;
+	  }
+	  /* Append the closure as the last parameter. Don't increment arity. */
+	  reg[arity] = p->hipe.closure;
+
+	  if (is_recursive) {
+	      /* BEAM called native, which now calls BEAM.
+		 Need to put a trap-frame on the beam stack.
+		 This may cause GC, which is safe now that
+		 the arguments, free vars, and most
+		 importantly the closure, all are in reg[]. */
+	      hipe_push_beam_trap_frame(p, reg, arity+1);
+	  }
+	  break;
+      }
+      case HIPE_MODE_SWITCH_RES_SUSPEND: {
+	  p->i = hipe_beam_pc_resume;
+	  p->arity = 0;
+	  erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
+	  if (p->status != P_SUSPENDED)
+	      erts_add_to_runq(p);
+	  erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+	  goto do_schedule;
+      }
+      case HIPE_MODE_SWITCH_RES_WAIT:
+      case HIPE_MODE_SWITCH_RES_WAIT_TIMEOUT: {
+	  /* same semantics, different debug trace messages */
+#ifdef ERTS_SMP
+	  /* XXX: BEAM has different entries for the locked and unlocked
+	     cases. HiPE doesn't, so we must check dynamically. */
+	  if (p->hipe_smp.have_receive_locks)
+	      p->hipe_smp.have_receive_locks = 0;
+	  else
+	      erts_smp_proc_lock(p, ERTS_PROC_LOCKS_MSG_RECEIVE);
+#endif
+	  p->i = hipe_beam_pc_resume;
+	  p->arity = 0;
+	  p->status = P_WAITING;
+	  erts_smp_proc_unlock(p, ERTS_PROC_LOCKS_MSG_RECEIVE);
+      do_schedule:
+	  {
+#if !(NR_ARG_REGS > 5)
+	      int reds_in = p->def_arg_reg[5];
+#endif
+	      p = schedule(p, reds_in - p->fcalls);
+#ifdef ERTS_SMP
+	      p->hipe_smp.have_receive_locks = 0;
+	      reg = p->scheduler_data->save_reg;
+#endif
+	  }
+	  {
+	      Eterm *argp;
+	      int i;
+	  
+	      argp = p->arg_reg;
+	      for (i = p->arity; --i >= 0;)
+		  reg[i] = argp[i];
+	  }
+	  {
+#if !(NR_ARG_REGS > 5)
+	      Eterm reds_in;
+#endif
+#if !(NR_ARG_REGS > 4)
+	      Eterm o_reds;
+#endif
+
+	      reds_in = p->fcalls;
+	      o_reds = 0;
+	      if (ERTS_PROC_GET_SAVED_CALLS_BUF(p)) {
+		  o_reds = reds_in;
+		  reds_in = 0;
+		  p->fcalls = 0;
+	      }
+	      p->def_arg_reg[4] = o_reds;
+	      p->def_arg_reg[5] = reds_in;
+	      if (p->i == hipe_beam_pc_resume) {
+		  p->i = NULL;
+		  p->arity = 0;
+		  goto do_resume;
+	      }
+	  }
+	  HIPE_CHECK_PCB(p);
+	  result = HIPE_MODE_SWITCH_RES_CALL;
+	  p->def_arg_reg[3] = result;
+	  return p;
+      }
+      case HIPE_MODE_SWITCH_RES_APPLY: {
+	  Eterm mfa[3], args;
+	  unsigned int arity;
+	  void *address;
+
+	  hipe_pop_params(p, 3, &mfa[0]);
+
+	  /* Unroll the arglist onto reg[]. */
+	  args = mfa[2];
+	  arity = 0;
+	  while (is_list(args)) {
+	      if (arity < 255) {
+		  reg[arity++] = CAR(list_val(args));
+		  args = CDR(list_val(args));
+	      } else
+		  goto do_apply_fail;
+	  }
+	  if (is_not_nil(args))
+	      goto do_apply_fail;
+
+	  /* find a native code entry point for {M,F,A} for a remote call */
+	  address = hipe_get_remote_na(mfa[0], mfa[1], arity);
+	  if (!address)
+		  goto do_apply_fail;
+	  p->hipe.ncallee = (void(*)(void)) address;
+	  result = hipe_tailcall_to_native(p, arity, reg);
+	  goto do_return_from_native;
+      do_apply_fail:
+	  p->freason = BADARG;
+	  goto do_throw_to_native;
+      }
+      default:
+	erl_exit(1, "hipe_mode_switch: result %#x\r\n", result);
+    }
+    HIPE_CHECK_PCB(p);
+    p->def_arg_reg[3] = result;
+#if NR_ARG_REGS > 4
+    p->def_arg_reg[4] = o_reds;
+#endif
+#if NR_ARG_REGS > 5
+    p->def_arg_reg[5] = reds_in;
+#endif
+    return p;
+}
+
+#define HIPE_INITIAL_NSTACK_SIZE	128
+
+/* PRE: size is zero or a power of two */
+static unsigned hipe_next_nstack_size(unsigned size)
+{
+    return size ? size * 2 : HIPE_INITIAL_NSTACK_SIZE;
+}
+
+#if 0 && defined(HIPE_NSTACK_GROWS_UP)
+#define hipe_nstack_avail(p)	((p)->hipe.nstend - (p)->hipe.nsp)
+void hipe_inc_nstack(Process *p)
+{
+    Eterm *old_nstack = p->hipe.nstack;
+    unsigned old_size = p->hipe.nstend - old_nstack;
+    unsigned new_size = hipe_next_nstack_size(old_size);
+    Eterm *new_nstack = erts_realloc(ERTS_ALC_T_HIPE,
+				     (char *) old_nstack,
+				     new_size*sizeof(Eterm));
+    p->hipe.nstend = new_nstack + new_size;
+    if (new_nstack != old_nstack) {
+	p->hipe.nsp = new_nstack + (p->hipe.nsp - old_nstack);
+	p->hipe.nstack = new_nstack;
+	if (p->hipe.nstgraylim)
+	    p->hipe.nstgraylim = 
+		new_nstack + (p->hipe.nstgraylim - old_nstack);
+	if (p->hipe.nstblacklim)
+	    p->hipe.nstblacklim = 
+		new_nstack + (p->hipe.nstblacklim - old_nstack);
+    }
+}
+#endif
+
+#if defined(HIPE_NSTACK_GROWS_DOWN)
+#define hipe_nstack_avail(p)	((unsigned)((p)->hipe.nsp - (p)->hipe.nstack))
+void hipe_inc_nstack(Process *p)
+{
+    unsigned old_size = p->hipe.nstend - p->hipe.nstack;
+    unsigned new_size = hipe_next_nstack_size(old_size);
+    Eterm *new_nstack = erts_alloc(ERTS_ALC_T_HIPE, new_size*sizeof(Eterm));
+    unsigned used_size = p->hipe.nstend - p->hipe.nsp;
+
+    sys_memcpy(new_nstack+new_size-used_size, p->hipe.nsp, used_size*sizeof(Eterm));
+    if (p->hipe.nstgraylim)
+	p->hipe.nstgraylim = new_nstack + new_size - (p->hipe.nstend - p->hipe.nstgraylim);
+    if (p->hipe.nstblacklim)
+	p->hipe.nstblacklim = new_nstack + new_size - (p->hipe.nstend - p->hipe.nstblacklim);
+    if (p->hipe.nstack)
+	erts_free(ERTS_ALC_T_HIPE, p->hipe.nstack);
+    p->hipe.nstack = new_nstack;
+    p->hipe.nstend = new_nstack + new_size;
+    p->hipe.nsp = new_nstack + new_size - used_size;
+}
+#endif
+
+static void hipe_check_nstack(Process *p, unsigned nwords)
+{
+    while (hipe_nstack_avail(p) < nwords)
+	hipe_inc_nstack(p);
+}
+
+void hipe_set_closure_stub(ErlFunEntry *fe, unsigned num_free)
+{
+    unsigned arity;
+
+    arity = fe->arity;
+    fe->native_address = (Eterm*) hipe_closure_stub_address(arity);
+}
+
+Eterm hipe_build_stacktrace(Process *p, struct StackTrace *s)
+{
+    int depth, i;
+    Uint heap_size;
+    Eterm *hp, *hp_end, mfa, m, f, head, *next_p, next;
+    const void *ra;
+    unsigned int a;
+
+    depth = s->depth;
+    if (depth < 1)
+	return NIL;
+
+    heap_size = 6 * depth;	/* each [{M,F,A}|_] is 2+4 == 6 words */
+    hp = HAlloc(p, heap_size);
+    hp_end = hp + heap_size;
+
+    head = NIL;
+    next_p = &head;
+
+    for (i = 0; i < depth; ++i) {
+	ra = (const void*)s->trace[i];
+	if (!hipe_find_mfa_from_ra(ra, &m, &f, &a))
+	    continue;
+	mfa = TUPLE3(hp, m, f, make_small(a));
+	hp += 4;
+	next = CONS(hp, mfa, NIL);
+	*next_p = next;
+	next_p = &CDR(list_val(next));
+	hp += 2;
+    }
+    HRelease(p, hp_end, hp);
+    return head;
+}