gimplify.c

/* A subroutine of gimplify_type_sizes to make sure that *EXPR_P,
   a size or position, has had all of its SAVE_EXPRs evaluated.
   We add any required statements to *STMT_P.  */

void
gimplify_one_sizepos (tree *expr_p, gimple_seq *stmt_p)
{
  tree expr = *expr_p;

  /* We don't do anything if the value isn't there, is constant, or contains
     A PLACEHOLDER_EXPR.  We also don't want to do anything if it's already
     a VAR_DECL.  If it's a VAR_DECL from another function, the gimplifier
     will want to replace it with a new variable, but that will cause problems
     if this type is from outside the function.  It's OK to have that here.  */
  if (is_gimple_sizepos (expr))
    return;

  *expr_p = unshare_expr (expr);

  gimplify_expr (expr_p, stmt_p, NULL, is_gimple_val, fb_rvalue);
}

/* Gimplify the body of statements of FNDECL and return a GIMPLE_BIND node
   containing the sequence of corresponding GIMPLE statements.  If DO_PARMS
   is true, also gimplify the parameters.  */

gbind *
gimplify_body (tree fndecl, bool do_parms)
{
  location_t saved_location = input_location;
  gimple_seq parm_stmts, seq;
  gimple outer_stmt;
  gbind *outer_bind;
  struct cgraph_node *cgn;

  timevar_push (TV_TREE_GIMPLIFY);

  /* Initialize for optimize_insn_for_s{ize,peed}_p possibly called during
     gimplification.  */
  default_rtl_profile ();

  gcc_assert (gimplify_ctxp == NULL);
  push_gimplify_context ();

  if (flag_openacc || flag_openmp)
    {
      gcc_assert (gimplify_omp_ctxp == NULL);
      if (lookup_attribute ("omp declare target", DECL_ATTRIBUTES (fndecl)))
	gimplify_omp_ctxp = new_omp_context (ORT_TARGET);
    }

  /* Unshare most shared trees in the body and in that of any nested functions.
     It would seem we don't have to do this for nested functions because
     they are supposed to be output and then the outer function gimplified
     first, but the g++ front end doesn't always do it that way.  */
  unshare_body (fndecl);
  unvisit_body (fndecl);

  cgn = cgraph_node::get (fndecl);
  if (cgn && cgn->origin)
    nonlocal_vlas = new hash_set<tree>;

  /* Make sure input_location isn't set to something weird.  */
  input_location = DECL_SOURCE_LOCATION (fndecl);

  /* Resolve callee-copies.  This has to be done before processing
     the body so that DECL_VALUE_EXPR gets processed correctly.  */
  parm_stmts = do_parms ? gimplify_parameters () : NULL;

  /* Gimplify the function's body.  */
  seq = NULL;
  gimplify_stmt (&DECL_SAVED_TREE (fndecl), &seq);
  outer_stmt = gimple_seq_first_stmt (seq);
  if (!outer_stmt)
    {
      outer_stmt = gimple_build_nop ();
      gimplify_seq_add_stmt (&seq, outer_stmt);
    }

  /* The body must contain exactly one statement, a GIMPLE_BIND.  If this is
     not the case, wrap everything in a GIMPLE_BIND to make it so.  */
  if (gimple_code (outer_stmt) == GIMPLE_BIND
      && gimple_seq_first (seq) == gimple_seq_last (seq))
    outer_bind = as_a <gbind *> (outer_stmt);
  else
    outer_bind = gimple_build_bind (NULL_TREE, seq, NULL);

  DECL_SAVED_TREE (fndecl) = NULL_TREE;

  /* If we had callee-copies statements, insert them at the beginning
     of the function and clear DECL_VALUE_EXPR_P on the parameters.  */
  if (!gimple_seq_empty_p (parm_stmts))
    {
      tree parm;

      gimplify_seq_add_seq (&parm_stmts, gimple_bind_body (outer_bind));
      gimple_bind_set_body (outer_bind, parm_stmts);

      for (parm = DECL_ARGUMENTS (current_function_decl);
	   parm; parm = DECL_CHAIN (parm))
	if (DECL_HAS_VALUE_EXPR_P (parm))
	  {
	    DECL_HAS_VALUE_EXPR_P (parm) = 0;
	    DECL_IGNORED_P (parm) = 0;
	  }
    }

  if (nonlocal_vlas)
    {
      if (nonlocal_vla_vars)
	{
	  /* tree-nested.c may later on call declare_vars (..., true);
	     which relies on BLOCK_VARS chain to be the tail of the
	     gimple_bind_vars chain.  Ensure we don't violate that
	     assumption.  */
	  if (gimple_bind_block (outer_bind)
	      == DECL_INITIAL (current_function_decl))
	    declare_vars (nonlocal_vla_vars, outer_bind, true);
	  else
	    BLOCK_VARS (DECL_INITIAL (current_function_decl))
	      = chainon (BLOCK_VARS (DECL_INITIAL (current_function_decl)),
			 nonlocal_vla_vars);
	  nonlocal_vla_vars = NULL_TREE;
	}
      delete nonlocal_vlas;
      nonlocal_vlas = NULL;
    }

  if ((flag_openacc || flag_openmp || flag_openmp_simd)
      && gimplify_omp_ctxp)
    {
      delete_omp_context (gimplify_omp_ctxp);
      gimplify_omp_ctxp = NULL;
    }

  pop_gimplify_context (outer_bind);
  gcc_assert (gimplify_ctxp == NULL);

#ifdef ENABLE_CHECKING
  if (!seen_error ())
    verify_gimple_in_seq (gimple_bind_body (outer_bind));
#endif

  timevar_pop (TV_TREE_GIMPLIFY);
  input_location = saved_location;

  return outer_bind;
}

typedef char *char_p; /* For DEF_VEC_P.  */

/* Return whether we should exclude FNDECL from instrumentation.  */

static bool
flag_instrument_functions_exclude_p (tree fndecl)
{
  vec<char_p> *v;

  v = (vec<char_p> *) flag_instrument_functions_exclude_functions;
  if (v && v->length () > 0)
    {
      const char *name;
      int i;
      char *s;

      name = lang_hooks.decl_printable_name (fndecl, 0);
      FOR_EACH_VEC_ELT (*v, i, s)
	if (strstr (name, s) != NULL)
	  return true;
    }

  v = (vec<char_p> *) flag_instrument_functions_exclude_files;
  if (v && v->length () > 0)
    {
      const char *name;
      int i;
      char *s;

      name = DECL_SOURCE_FILE (fndecl);
      FOR_EACH_VEC_ELT (*v, i, s)
	if (strstr (name, s) != NULL)
	  return true;
    }

  return false;
}

/* Entry point to the gimplification pass.  FNDECL is the FUNCTION_DECL
   node for the function we want to gimplify.

   Return the sequence of GIMPLE statements corresponding to the body
   of FNDECL.  */

void
gimplify_function_tree (tree fndecl)
{
  tree parm, ret;
  gimple_seq seq;
  gbind *bind;

  gcc_assert (!gimple_body (fndecl));

  if (DECL_STRUCT_FUNCTION (fndecl))
    push_cfun (DECL_STRUCT_FUNCTION (fndecl));
  else
    push_struct_function (fndecl);

  /* Tentatively set PROP_gimple_lva here, and reset it in gimplify_va_arg_expr
     if necessary.  */
  cfun->curr_properties |= PROP_gimple_lva;

  for (parm = DECL_ARGUMENTS (fndecl); parm ; parm = DECL_CHAIN (parm))
    {
      /* Preliminarily mark non-addressed complex variables as eligible
         for promotion to gimple registers.  We'll transform their uses
         as we find them.  */
      if ((TREE_CODE (TREE_TYPE (parm)) == COMPLEX_TYPE
	   || TREE_CODE (TREE_TYPE (parm)) == VECTOR_TYPE)
          && !TREE_THIS_VOLATILE (parm)
          && !needs_to_live_in_memory (parm))
        DECL_GIMPLE_REG_P (parm) = 1;
    }

  ret = DECL_RESULT (fndecl);
  if ((TREE_CODE (TREE_TYPE (ret)) == COMPLEX_TYPE
       || TREE_CODE (TREE_TYPE (ret)) == VECTOR_TYPE)
      && !needs_to_live_in_memory (ret))
    DECL_GIMPLE_REG_P (ret) = 1;

  bind = gimplify_body (fndecl, true);

  /* The tree body of the function is no longer needed, replace it
     with the new GIMPLE body.  */
  seq = NULL;
  gimple_seq_add_stmt (&seq, bind);
  gimple_set_body (fndecl, seq);

  /* If we're instrumenting function entry/exit, then prepend the call to
     the entry hook and wrap the whole function in a TRY_FINALLY_EXPR to
     catch the exit hook.  */
  /* ??? Add some way to ignore exceptions for this TFE.  */
  if (flag_instrument_function_entry_exit
      && !DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (fndecl)
      && !flag_instrument_functions_exclude_p (fndecl))
    {
      tree x;
      gbind *new_bind;
      gimple tf;
      gimple_seq cleanup = NULL, body = NULL;
      tree tmp_var;
      gcall *call;

      x = builtin_decl_implicit (BUILT_IN_RETURN_ADDRESS);
      call = gimple_build_call (x, 1, integer_zero_node);
      tmp_var = create_tmp_var (ptr_type_node, "return_addr");
      gimple_call_set_lhs (call, tmp_var);
      gimplify_seq_add_stmt (&cleanup, call);
      x = builtin_decl_implicit (BUILT_IN_PROFILE_FUNC_EXIT);
      call = gimple_build_call (x, 2,
				build_fold_addr_expr (current_function_decl),
				tmp_var);
      gimplify_seq_add_stmt (&cleanup, call);
      tf = gimple_build_try (seq, cleanup, GIMPLE_TRY_FINALLY);

      x = builtin_decl_implicit (BUILT_IN_RETURN_ADDRESS);
      call = gimple_build_call (x, 1, integer_zero_node);
      tmp_var = create_tmp_var (ptr_type_node, "return_addr");
      gimple_call_set_lhs (call, tmp_var);
      gimplify_seq_add_stmt (&body, call);
      x = builtin_decl_implicit (BUILT_IN_PROFILE_FUNC_ENTER);
      call = gimple_build_call (x, 2,
				build_fold_addr_expr (current_function_decl),
				tmp_var);
      gimplify_seq_add_stmt (&body, call);
      gimplify_seq_add_stmt (&body, tf);
      new_bind = gimple_build_bind (NULL, body, gimple_bind_block (bind));
      /* Clear the block for BIND, since it is no longer directly inside
         the function, but within a try block.  */
      gimple_bind_set_block (bind, NULL);

      /* Replace the current function body with the body
         wrapped in the try/finally TF.  */
      seq = NULL;
      gimple_seq_add_stmt (&seq, new_bind);
      gimple_set_body (fndecl, seq);
      bind = new_bind;
    }

  if ((flag_sanitize & SANITIZE_THREAD) != 0
      && !lookup_attribute ("no_sanitize_thread", DECL_ATTRIBUTES (fndecl)))
    {
      gcall *call = gimple_build_call_internal (IFN_TSAN_FUNC_EXIT, 0);
      gimple tf = gimple_build_try (seq, call, GIMPLE_TRY_FINALLY);
      gbind *new_bind = gimple_build_bind (NULL, tf, gimple_bind_block (bind));
      /* Clear the block for BIND, since it is no longer directly inside
	 the function, but within a try block.  */
      gimple_bind_set_block (bind, NULL);
      /* Replace the current function body with the body
	 wrapped in the try/finally TF.  */
      seq = NULL;
      gimple_seq_add_stmt (&seq, new_bind);
      gimple_set_body (fndecl, seq);
    }

  DECL_SAVED_TREE (fndecl) = NULL_TREE;
  cfun->curr_properties |= PROP_gimple_any;

  pop_cfun ();
}

/* Return a dummy expression of type TYPE in order to keep going after an
   error.  */

static tree
dummy_object (tree type)
{
  tree t = build_int_cst (build_pointer_type (type), 0);
  return build2 (MEM_REF, type, t, t);
}

/* Call the target expander for evaluating a va_arg call of VALIST
   and TYPE.  */

tree
gimplify_va_arg_internal (tree valist, tree type, location_t loc,
			  gimple_seq *pre_p, gimple_seq *post_p)
{
  tree have_va_type = TREE_TYPE (valist);
  tree cano_type = targetm.canonical_va_list_type (have_va_type);

  if (cano_type != NULL_TREE)
    have_va_type = cano_type;

  /* Make it easier for the backends by protecting the valist argument
     from multiple evaluations.  */
  if (TREE_CODE (have_va_type) == ARRAY_TYPE)
    {
      /* For this case, the backends will be expecting a pointer to
	 TREE_TYPE (abi), but it's possible we've
	 actually been given an array (an actual TARGET_FN_ABI_VA_LIST).
	 So fix it.  */
      if (TREE_CODE (TREE_TYPE (valist)) == ARRAY_TYPE)
	{
	  tree p1 = build_pointer_type (TREE_TYPE (have_va_type));
	  valist = fold_convert_loc (loc, p1,
				     build_fold_addr_expr_loc (loc, valist));
	}

      gimplify_expr (&valist, pre_p, post_p, is_gimple_val, fb_rvalue);
    }
  else
    gimplify_expr (&valist, pre_p, post_p, is_gimple_min_lval, fb_lvalue);

  return targetm.gimplify_va_arg_expr (valist, type, pre_p, post_p);
}

/* Gimplify __builtin_va_arg, aka VA_ARG_EXPR, which is not really a
   builtin function, but a very special sort of operator.  */

enum gimplify_status
gimplify_va_arg_expr (tree *expr_p, gimple_seq *pre_p,
		      gimple_seq *post_p ATTRIBUTE_UNUSED)
{
  tree promoted_type, have_va_type;
  tree valist = TREE_OPERAND (*expr_p, 0);
  tree type = TREE_TYPE (*expr_p);
  tree t, tag, ap;
  location_t loc = EXPR_LOCATION (*expr_p);

  /* Verify that valist is of the proper type.  */
  have_va_type = TREE_TYPE (valist);
  if (have_va_type == error_mark_node)
    return GS_ERROR;
  have_va_type = targetm.canonical_va_list_type (have_va_type);

  if (have_va_type == NULL_TREE)
    {
      error_at (loc, "first argument to %<va_arg%> not of type %<va_list%>");
      return GS_ERROR;
    }

  /* Generate a diagnostic for requesting data of a type that cannot
     be passed through `...' due to type promotion at the call site.  */
  if ((promoted_type = lang_hooks.types.type_promotes_to (type))
	   != type)
    {
      static bool gave_help;
      bool warned;

      /* Unfortunately, this is merely undefined, rather than a constraint
	 violation, so we cannot make this an error.  If this call is never
	 executed, the program is still strictly conforming.  */
      warned = warning_at (loc, 0,
	  		   "%qT is promoted to %qT when passed through %<...%>",
			   type, promoted_type);
      if (!gave_help && warned)
	{
	  gave_help = true;
	  inform (loc, "(so you should pass %qT not %qT to %<va_arg%>)",
		  promoted_type, type);
	}

      /* We can, however, treat "undefined" any way we please.
	 Call abort to encourage the user to fix the program.  */
      if (warned)
	inform (loc, "if this code is reached, the program will abort");
      /* Before the abort, allow the evaluation of the va_list
	 expression to exit or longjmp.  */
      gimplify_and_add (valist, pre_p);
      t = build_call_expr_loc (loc,
			       builtin_decl_implicit (BUILT_IN_TRAP), 0);
      gimplify_and_add (t, pre_p);

      /* This is dead code, but go ahead and finish so that the
	 mode of the result comes out right.  */
      *expr_p = dummy_object (type);
      return GS_ALL_DONE;
    }

  /* Transform a VA_ARG_EXPR into an VA_ARG internal function.  */
  ap = build_fold_addr_expr_loc (loc, valist);
  tag = build_int_cst (build_pointer_type (type), 0);
  *expr_p = build_call_expr_internal_loc (loc, IFN_VA_ARG, type, 2, ap, tag);

  /* Clear the tentatively set PROP_gimple_lva, to indicate that IFN_VA_ARG
     needs to be expanded.  */
  cfun->curr_properties &= ~PROP_gimple_lva;

  return GS_OK;
}

/* Build a new GIMPLE_ASSIGN tuple and append it to the end of *SEQ_P.

   DST/SRC are the destination and source respectively.  You can pass
   ungimplified trees in DST or SRC, in which case they will be
   converted to a gimple operand if necessary.

   This function returns the newly created GIMPLE_ASSIGN tuple.  */

gimple
gimplify_assign (tree dst, tree src, gimple_seq *seq_p)
{
  tree t = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
  gimplify_and_add (t, seq_p);
  ggc_free (t);
  return gimple_seq_last_stmt (*seq_p);
}

inline hashval_t
gimplify_hasher::hash (const value_type *p)
{
  tree t = p->val;
  return iterative_hash_expr (t, 0);
}

inline bool
gimplify_hasher::equal (const value_type *p1, const compare_type *p2)
{
  tree t1 = p1->val;
  tree t2 = p2->val;
  enum tree_code code = TREE_CODE (t1);

  if (TREE_CODE (t2) != code
      || TREE_TYPE (t1) != TREE_TYPE (t2))
    return false;

  if (!operand_equal_p (t1, t2, 0))
    return false;

#ifdef ENABLE_CHECKING
  /* Only allow them to compare equal if they also hash equal; otherwise
     results are nondeterminate, and we fail bootstrap comparison.  */
  gcc_assert (hash (p1) == hash (p2));
#endif

  return true;
}