re PR tree-optimization/35609 ("is used uninitialized in this function" should be...

[gcc.git] / gcc / integrate.c

/* Procedure integration for GCC.
   Copyright (C) 1988, 1991, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   Contributed by Michael Tiemann (tiemann@cygnus.com)

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"

#include "rtl.h"
#include "tree.h"
#include "tm_p.h"
#include "regs.h"
#include "flags.h"
#include "debug.h"
#include "insn-config.h"
#include "expr.h"
#include "output.h"
#include "recog.h"
#include "integrate.h"
#include "real.h"
#include "except.h"
#include "function.h"
#include "toplev.h"
#include "intl.h"
#include "params.h"
#include "ggc.h"
#include "target.h"
#include "langhooks.h"
#include "tree-pass.h"
#include "df.h"

/* Round to the next highest integer that meets the alignment.  */
#define CEIL_ROUND(VALUE,ALIGN)	(((VALUE) + (ALIGN) - 1) & ~((ALIGN)- 1))
\f

/* Private type used by {get/has}_hard_reg_initial_val.  */
typedef struct initial_value_pair GTY(()) {
  rtx hard_reg;
  rtx pseudo;
} initial_value_pair;
typedef struct initial_value_struct GTY(()) {
  int num_entries;
  int max_entries;
  initial_value_pair * GTY ((length ("%h.num_entries"))) entries;
} initial_value_struct;

static void set_block_origin_self (tree);
static void set_block_abstract_flags (tree, int);
\f

/* Return false if the function FNDECL cannot be inlined on account of its
   attributes, true otherwise.  */
bool
function_attribute_inlinable_p (const_tree fndecl)
{
  if (targetm.attribute_table)
    {
      const_tree a;

      for (a = DECL_ATTRIBUTES (fndecl); a; a = TREE_CHAIN (a))
	{
	  const_tree name = TREE_PURPOSE (a);
	  int i;

	  for (i = 0; targetm.attribute_table[i].name != NULL; i++)
	    if (is_attribute_p (targetm.attribute_table[i].name, name))
	      return targetm.function_attribute_inlinable_p (fndecl);
	}
    }

  return true;
}
\f
/* Given a pointer to some BLOCK node, if the BLOCK_ABSTRACT_ORIGIN for the
   given BLOCK node is NULL, set the BLOCK_ABSTRACT_ORIGIN for the node so
   that it points to the node itself, thus indicating that the node is its
   own (abstract) origin.  Additionally, if the BLOCK_ABSTRACT_ORIGIN for
   the given node is NULL, recursively descend the decl/block tree which
   it is the root of, and for each other ..._DECL or BLOCK node contained
   therein whose DECL_ABSTRACT_ORIGINs or BLOCK_ABSTRACT_ORIGINs are also
   still NULL, set *their* DECL_ABSTRACT_ORIGIN or BLOCK_ABSTRACT_ORIGIN
   values to point to themselves.  */

static void
set_block_origin_self (tree stmt)
{
  if (BLOCK_ABSTRACT_ORIGIN (stmt) == NULL_TREE)
    {
      BLOCK_ABSTRACT_ORIGIN (stmt) = stmt;

      {
	tree local_decl;

	for (local_decl = BLOCK_VARS (stmt);
	     local_decl != NULL_TREE;
	     local_decl = TREE_CHAIN (local_decl))
	  set_decl_origin_self (local_decl);	/* Potential recursion.  */
      }

      {
	tree subblock;

	for (subblock = BLOCK_SUBBLOCKS (stmt);
	     subblock != NULL_TREE;
	     subblock = BLOCK_CHAIN (subblock))
	  set_block_origin_self (subblock);	/* Recurse.  */
      }
    }
}

/* Given a pointer to some ..._DECL node, if the DECL_ABSTRACT_ORIGIN for
   the given ..._DECL node is NULL, set the DECL_ABSTRACT_ORIGIN for the
   node to so that it points to the node itself, thus indicating that the
   node represents its own (abstract) origin.  Additionally, if the
   DECL_ABSTRACT_ORIGIN for the given node is NULL, recursively descend
   the decl/block tree of which the given node is the root of, and for
   each other ..._DECL or BLOCK node contained therein whose
   DECL_ABSTRACT_ORIGINs or BLOCK_ABSTRACT_ORIGINs are also still NULL,
   set *their* DECL_ABSTRACT_ORIGIN or BLOCK_ABSTRACT_ORIGIN values to
   point to themselves.  */

void
set_decl_origin_self (tree decl)
{
  if (DECL_ABSTRACT_ORIGIN (decl) == NULL_TREE)
    {
      DECL_ABSTRACT_ORIGIN (decl) = decl;
      if (TREE_CODE (decl) == FUNCTION_DECL)
	{
	  tree arg;

	  for (arg = DECL_ARGUMENTS (decl); arg; arg = TREE_CHAIN (arg))
	    DECL_ABSTRACT_ORIGIN (arg) = arg;
	  if (DECL_INITIAL (decl) != NULL_TREE
	      && DECL_INITIAL (decl) != error_mark_node)
	    set_block_origin_self (DECL_INITIAL (decl));
	}
    }
}
\f
/* Given a pointer to some BLOCK node, and a boolean value to set the
   "abstract" flags to, set that value into the BLOCK_ABSTRACT flag for
   the given block, and for all local decls and all local sub-blocks
   (recursively) which are contained therein.  */

static void
set_block_abstract_flags (tree stmt, int setting)
{
  tree local_decl;
  tree subblock;

  BLOCK_ABSTRACT (stmt) = setting;

  for (local_decl = BLOCK_VARS (stmt);
       local_decl != NULL_TREE;
       local_decl = TREE_CHAIN (local_decl))
    set_decl_abstract_flags (local_decl, setting);

  for (subblock = BLOCK_SUBBLOCKS (stmt);
       subblock != NULL_TREE;
       subblock = BLOCK_CHAIN (subblock))
    set_block_abstract_flags (subblock, setting);
}

/* Given a pointer to some ..._DECL node, and a boolean value to set the
   "abstract" flags to, set that value into the DECL_ABSTRACT flag for the
   given decl, and (in the case where the decl is a FUNCTION_DECL) also
   set the abstract flags for all of the parameters, local vars, local
   blocks and sub-blocks (recursively) to the same setting.  */

void
set_decl_abstract_flags (tree decl, int setting)
{
  DECL_ABSTRACT (decl) = setting;
  if (TREE_CODE (decl) == FUNCTION_DECL)
    {
      tree arg;

      for (arg = DECL_ARGUMENTS (decl); arg; arg = TREE_CHAIN (arg))
	DECL_ABSTRACT (arg) = setting;
      if (DECL_INITIAL (decl) != NULL_TREE
	  && DECL_INITIAL (decl) != error_mark_node)
	set_block_abstract_flags (DECL_INITIAL (decl), setting);
    }
}
\f
/* Functions to keep track of the values hard regs had at the start of
   the function.  */

rtx
get_hard_reg_initial_reg (struct function *fun, rtx reg)
{
  struct initial_value_struct *ivs = fun->hard_reg_initial_vals;
  int i;

  if (ivs == 0)
    return NULL_RTX;

  for (i = 0; i < ivs->num_entries; i++)
    if (rtx_equal_p (ivs->entries[i].pseudo, reg))
      return ivs->entries[i].hard_reg;

  return NULL_RTX;
}

/* Make sure that there's a pseudo register of mode MODE that stores the
   initial value of hard register REGNO.  Return an rtx for such a pseudo.  */

rtx
get_hard_reg_initial_val (enum machine_mode mode, unsigned int regno)
{
  struct initial_value_struct *ivs;
  rtx rv;

  rv = has_hard_reg_initial_val (mode, regno);
  if (rv)
    return rv;

  ivs = cfun->hard_reg_initial_vals;
  if (ivs == 0)
    {
      ivs = ggc_alloc (sizeof (initial_value_struct));
      ivs->num_entries = 0;
      ivs->max_entries = 5;
      ivs->entries = ggc_alloc (5 * sizeof (initial_value_pair));
      cfun->hard_reg_initial_vals = ivs;
    }

  if (ivs->num_entries >= ivs->max_entries)
    {
      ivs->max_entries += 5;
      ivs->entries = ggc_realloc (ivs->entries,
				  ivs->max_entries
				  * sizeof (initial_value_pair));
    }

  ivs->entries[ivs->num_entries].hard_reg = gen_rtx_REG (mode, regno);
  ivs->entries[ivs->num_entries].pseudo = gen_reg_rtx (mode);

  return ivs->entries[ivs->num_entries++].pseudo;
}

/* See if get_hard_reg_initial_val has been used to create a pseudo
   for the initial value of hard register REGNO in mode MODE.  Return
   the associated pseudo if so, otherwise return NULL.  */

rtx
has_hard_reg_initial_val (enum machine_mode mode, unsigned int regno)
{
  struct initial_value_struct *ivs;
  int i;

  ivs = cfun->hard_reg_initial_vals;
  if (ivs != 0)
    for (i = 0; i < ivs->num_entries; i++)
      if (GET_MODE (ivs->entries[i].hard_reg) == mode
	  && REGNO (ivs->entries[i].hard_reg) == regno)
	return ivs->entries[i].pseudo;

  return NULL_RTX;
}

unsigned int
emit_initial_value_sets (void)
{
  struct initial_value_struct *ivs = cfun->hard_reg_initial_vals;
  int i;
  rtx seq;

  if (ivs == 0)
    return 0;

  start_sequence ();
  for (i = 0; i < ivs->num_entries; i++)
    emit_move_insn (ivs->entries[i].pseudo, ivs->entries[i].hard_reg);
  seq = get_insns ();
  end_sequence ();

  emit_insn_at_entry (seq);
  return 0;
}

struct tree_opt_pass pass_initial_value_sets =
{
  "initvals",                           /* name */
  NULL,                                 /* gate */
  emit_initial_value_sets,              /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  0,                                    /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  TODO_dump_func,                       /* todo_flags_finish */
  0                                     /* letter */
};

/* If the backend knows where to allocate pseudos for hard
   register initial values, register these allocations now.  */
void
allocate_initial_values (rtx *reg_equiv_memory_loc)
{
  if (targetm.allocate_initial_value)
    {
      struct initial_value_struct *ivs = cfun->hard_reg_initial_vals;
      int i;

      if (ivs == 0)
	return;

      for (i = 0; i < ivs->num_entries; i++)
	{
	  int regno = REGNO (ivs->entries[i].pseudo);
	  rtx x = targetm.allocate_initial_value (ivs->entries[i].hard_reg);
  
	  if (x && REG_N_SETS (REGNO (ivs->entries[i].pseudo)) <= 1)
	    {
	      if (MEM_P (x))
		reg_equiv_memory_loc[regno] = x;
	      else
		{
		  basic_block bb;
		  int new_regno;

		  gcc_assert (REG_P (x));
		  new_regno = REGNO (x);
		  reg_renumber[regno] = new_regno;
		  /* Poke the regno right into regno_reg_rtx so that even
		     fixed regs are accepted.  */
		  SET_REGNO (ivs->entries[i].pseudo, new_regno);
		  /* Update global register liveness information.  */
		  FOR_EACH_BB (bb)
		    {
		      if (REGNO_REG_SET_P(df_get_live_in (bb), regno))
			SET_REGNO_REG_SET (df_get_live_in (bb), new_regno);
		      if (REGNO_REG_SET_P(df_get_live_out (bb), regno))
			SET_REGNO_REG_SET (df_get_live_out (bb), new_regno);
		    }
		}
	    }
	}
    }
}

#include "gt-integrate.h"