gcc/d/d-gimplify.cc

   1 /* D-specific tree lowering bits; see also gimple.cc.
   2    Copyright (C) 2020-2022 Free Software Foundation, Inc.
   3
   4 GCC is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation; either version 3, or (at your option)
   7 any later version.
   8
   9 GCC is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with GCC; see the file COPYING3.  If not see
  16 <http://www.gnu.org/licenses/>.  */
  17
  18 #include "config.h"
  19 #include "system.h"
  20 #include "coretypes.h"
  21
  22 #include "dmd/globals.h"
  23
  24 #include "tree.h"
  25 #include "gimple-expr.h"
  26 #include "gimplify.h"
  27
  28 #include "d-tree.h"
  29
  30
  31 /* Return TRUE if an operand OP of a given TYPE being copied has no data.
  32    The middle-end does a similar check with zero sized types.  */
  33
  34 static bool
  35 empty_modify_p (tree type, tree op)
  36 {
  37   tree_code code = TREE_CODE (op);
  38   switch (code)
  39     {
  40     case COMPOUND_EXPR:
  41       return empty_modify_p (type, TREE_OPERAND (op, 1));
  42
  43     case CONSTRUCTOR:
  44       /* Non-empty construcors are valid.  */
  45       if (CONSTRUCTOR_NELTS (op) != 0 || TREE_CLOBBER_P (op))
  46         return false;
  47       break;
  48
  49     case CALL_EXPR:
  50       /* Leave nrvo alone because it isn't a copy.  */
  51       if (CALL_EXPR_RETURN_SLOT_OPT (op))
  52         return false;
  53       break;
  54
  55     default:
  56       /* If the operand doesn't have a simple form.  */
  57       if (!is_gimple_lvalue (op) && !INDIRECT_REF_P (op))
  58         return false;
  59       break;
  60     }
  61
  62   return empty_aggregate_p (type);
  63 }
  64
  65 /* Return TRUE if EXPR is a COMPONENT_REF to a bit-field declaration.  */
  66
  67 static bool
  68 bit_field_ref (const_tree expr)
  69 {
  70   if (TREE_CODE (expr) == COMPONENT_REF
  71       && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
  72     return true;
  73
  74   return false;
  75 }
  76
  77 /* Gimplify assignment from an INIT_EXPR or MODIFY_EXPR.  */
  78
  79 static gimplify_status
  80 d_gimplify_modify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
  81 {
  82   tree op0 = TREE_OPERAND (*expr_p, 0);
  83   tree op1 = TREE_OPERAND (*expr_p, 1);
  84
  85   if (error_operand_p (op0) || error_operand_p (op1))
  86     return GS_UNHANDLED;
  87
  88   /* Remove any copies of empty aggregates.  */
  89   if (empty_modify_p (TREE_TYPE (op0), op1))
  90     {
  91       gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p, post_p,
  92                      is_gimple_lvalue, fb_lvalue);
  93
  94       if (TREE_SIDE_EFFECTS (op1))
  95         gimplify_and_add (op1, pre_p);
  96
  97       *expr_p = TREE_OPERAND (*expr_p, 0);
  98       return GS_OK;
  99     }
 100
 101   /* If the back end isn't clever enough to know that the lhs and rhs
 102      types are the same, add an explicit conversion.  */
 103   if ((AGGREGATE_TYPE_P (TREE_TYPE (op0)) || AGGREGATE_TYPE_P (TREE_TYPE (op1)))
 104       && !useless_type_conversion_p (TREE_TYPE (op1), TREE_TYPE (op0)))
 105     {
 106       TREE_OPERAND (*expr_p, 1) = build1 (VIEW_CONVERT_EXPR,
 107                                           TREE_TYPE (op0), op1);
 108       return GS_OK;
 109     }
 110
 111   /* Same as above, but for bit-field assignments.  */
 112   if ((bit_field_ref (op0) || bit_field_ref (op1))
 113       && TREE_TYPE (op0) != TREE_TYPE (op1))
 114     {
 115       TREE_OPERAND (*expr_p, 1) = convert (TREE_TYPE (op0), op1);
 116       return GS_OK;
 117     }
 118
 119   return GS_UNHANDLED;
 120 }
 121
 122 /* Gimplify an ADDR_EXPR node.  */
 123
 124 static gimplify_status
 125 d_gimplify_addr_expr (tree *expr_p)
 126 {
 127   tree op0 = TREE_OPERAND (*expr_p, 0);
 128   /* Constructors are not lvalues, so make them one.  */
 129   if (TREE_CODE (op0) == CONSTRUCTOR)
 130     {
 131       TREE_OPERAND (*expr_p, 0) = force_target_expr (op0);
 132       return GS_OK;
 133     }
 134
 135   return GS_UNHANDLED;
 136 }
 137
 138 /* Gimplify a CALL_EXPR node.  */
 139
 140 static gimplify_status
 141 d_gimplify_call_expr (tree *expr_p, gimple_seq *pre_p)
 142 {
 143   /* Strictly evaluate all arguments from left to right.  */
 144   int nargs = call_expr_nargs (*expr_p);
 145   location_t loc = EXPR_LOC_OR_LOC (*expr_p, input_location);
 146
 147   /* No need to enforce evaluation order if only one argument.  */
 148   if (nargs < 2)
 149     return GS_UNHANDLED;
 150
 151   /* Or if all arguments are already free of side-effects.  */
 152   bool has_side_effects = false;
 153   for (int i = 0; i < nargs; i++)
 154     {
 155       if (TREE_SIDE_EFFECTS (CALL_EXPR_ARG (*expr_p, i)))
 156         {
 157           has_side_effects = true;
 158           break;
 159         }
 160     }
 161
 162   if (!has_side_effects)
 163     return GS_UNHANDLED;
 164
 165   /* Leave the last argument for gimplify_call_expr.  */
 166   for (int i = 0; i < nargs - 1; i++)
 167     {
 168       tree new_arg = CALL_EXPR_ARG (*expr_p, i);
 169
 170       /* If argument has a side-effect, gimplify_arg will handle it.  */
 171       if (gimplify_arg (&new_arg, pre_p, loc) == GS_ERROR)
 172         return GS_ERROR;
 173
 174       /* Even if an argument itself doesn't have any side-effects, it
 175          might be altered by another argument in the list.  */
 176       if (new_arg == CALL_EXPR_ARG (*expr_p, i)
 177           && !really_constant_p (new_arg))
 178         new_arg = get_formal_tmp_var (new_arg, pre_p);
 179
 180       CALL_EXPR_ARG (*expr_p, i) = new_arg;
 181     }
 182
 183   return GS_OK;
 184 }
 185
 186 /* Gimplify an UNSIGNED_RSHIFT_EXPR node.  */
 187
 188 static gimplify_status
 189 d_gimplify_unsigned_rshift_expr (tree *expr_p)
 190 {
 191   /* Convert op0 to an unsigned type.  */
 192   tree op0 = TREE_OPERAND (*expr_p, 0);
 193   tree op1 = TREE_OPERAND (*expr_p, 1);
 194   tree type = d_unsigned_type (TREE_TYPE (op0));
 195
 196   *expr_p = convert (TREE_TYPE (*expr_p),
 197                      build2 (RSHIFT_EXPR, type, convert (type, op0), op1));
 198   return GS_OK;
 199 }
 200
 201 /* Gimplify an unary expression node.  */
 202
 203 static gimplify_status
 204 d_gimplify_unary_expr (tree *expr_p)
 205 {
 206   tree op0 = TREE_OPERAND (*expr_p, 0);
 207
 208   if (error_operand_p (op0))
 209     return GS_UNHANDLED;
 210
 211   /* Front end doesn't know that bit-field types are really different
 212      from basic types, add an explicit conversion in unary expressions.  */
 213   if (bit_field_ref (op0) && TREE_TYPE (op0) != TREE_TYPE (*expr_p))
 214     {
 215       TREE_OPERAND (*expr_p, 0) = convert (TREE_TYPE (*expr_p), op0);
 216       return GS_OK;
 217     }
 218
 219   return GS_UNHANDLED;
 220 }
 221
 222 /* Gimplify a binary expression node.  */
 223
 224 static gimplify_status
 225 d_gimplify_binary_expr (tree *expr_p)
 226 {
 227   tree op0 = TREE_OPERAND (*expr_p, 0);
 228   tree op1 = TREE_OPERAND (*expr_p, 1);
 229
 230   if (error_operand_p (op0) || error_operand_p (op1))
 231     return GS_UNHANDLED;
 232
 233   /* Front end doesn't know that bit-field types are really different
 234      from basic types, add an explicit conversion in binary expressions.  */
 235   if (bit_field_ref (op0) || bit_field_ref (op1))
 236     {
 237       if (TREE_TYPE (op0) != TREE_TYPE (*expr_p))
 238         TREE_OPERAND (*expr_p, 0) = convert (TREE_TYPE (*expr_p), op0);
 239
 240       if (TREE_TYPE (op1) != TREE_TYPE (*expr_p))
 241         TREE_OPERAND (*expr_p, 1) = convert (TREE_TYPE (*expr_p), op1);
 242
 243       return GS_OK;
 244     }
 245
 246   return GS_UNHANDLED;
 247 }
 248
 249 /* Implements the lang_hooks.gimplify_expr routine for language D.
 250    Do gimplification of D specific expression trees in EXPR_P.  */
 251
 252 int
 253 d_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 254 {
 255   switch (TREE_CODE (*expr_p))
 256     {
 257     case INIT_EXPR:
 258     case MODIFY_EXPR:
 259       return d_gimplify_modify_expr (expr_p, pre_p, post_p);
 260
 261     case ADDR_EXPR:
 262       return d_gimplify_addr_expr (expr_p);
 263
 264     case CALL_EXPR:
 265       return d_gimplify_call_expr (expr_p, pre_p);
 266
 267     case UNSIGNED_RSHIFT_EXPR:
 268       return d_gimplify_unsigned_rshift_expr (expr_p);
 269
 270     case FLOAT_MOD_EXPR:
 271       gcc_unreachable ();
 272
 273     default:
 274       if (UNARY_CLASS_P (*expr_p) && !CONVERT_EXPR_P (*expr_p))
 275         return d_gimplify_unary_expr (expr_p);
 276       if (BINARY_CLASS_P (*expr_p))
 277         return d_gimplify_binary_expr (expr_p);
 278       break;
 279     }
 280
 281   return GS_UNHANDLED;
 282 }