gcc/tree-data-ref.h

   1 /* Data references and dependences detectors.
   2    Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <pop@cri.ensmp.fr>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_TREE_DATA_REF_H
  22 #define GCC_TREE_DATA_REF_H
  23
  24 #include "lambda.h"
  25
  26 /** {base_address + offset + init} is the first location accessed by data-ref
  27       in the loop, and step is the stride of data-ref in the loop in bytes;
  28       e.g.:
  29
  30                        Example 1                      Example 2
  31       data-ref         a[j].b[i][j]                   a + x + 16B (a is int*)
  32
  33 First location info:
  34       base_address     &a                             a
  35       offset           j_0*D_j + i_0*D_i + C_a        x
  36       init             C_b                            16
  37       step             D_j                            4
  38       access_fn        NULL                           {16, +, 1}
  39
  40 Base object info:
  41       base_object      a                              NULL
  42       access_fn        <access_fns of indexes of b>   NULL
  43
  44   **/
  45 struct first_location_in_loop
  46 {
  47   tree base_address;
  48   tree offset;
  49   tree init;
  50   tree step;
  51   /* Access function related to first location in the loop.  */
  52   VEC(tree,heap) *access_fns;
  53
  54 };
  55
  56 struct base_object_info
  57 {
  58   /* The object.  */
  59   tree base_object;
  60
  61   /* A list of chrecs.  Access functions related to BASE_OBJECT.  */
  62   VEC(tree,heap) *access_fns;
  63 };
  64
  65 enum data_ref_type {
  66   ARRAY_REF_TYPE,
  67   POINTER_REF_TYPE
  68 };
  69
  70 struct data_reference
  71 {
  72   /* A pointer to the statement that contains this DR.  */
  73   tree stmt;
  74
  75   /* A pointer to the ARRAY_REF node.  */
  76   tree ref;
  77
  78   /* Auxiliary info specific to a pass.  */
  79   int aux;
  80
  81   /* True when the data reference is in RHS of a stmt.  */
  82   bool is_read;
  83
  84   /* First location accessed by the data-ref in the loop.  */
  85   struct first_location_in_loop first_location;
  86
  87   /* Base object related info.  */
  88   struct base_object_info object_info;
  89
  90   /* Aliasing information.  This field represents the symbol that
  91      should be aliased by a pointer holding the address of this data
  92      reference.  If the original data reference was a pointer
  93      dereference, then this field contains the memory tag that should
  94      be used by the new vector-pointer.  */
  95   tree memtag;
  96   struct ptr_info_def *ptr_info;
  97   subvar_t subvars;
  98
  99   /* Alignment information.  */
 100   /* The offset of the data-reference from its base in bytes.  */
 101   tree misalignment;
 102   /* The maximum data-ref's alignment.  */
 103   tree aligned_to;
 104
 105   /* The type of the data-ref.  */
 106   enum data_ref_type type;
 107 };
 108
 109 typedef struct data_reference *data_reference_p;
 110 DEF_VEC_P(data_reference_p);
 111 DEF_VEC_ALLOC_P (data_reference_p, heap);
 112
 113 #define DR_STMT(DR)                (DR)->stmt
 114 #define DR_REF(DR)                 (DR)->ref
 115 #define DR_BASE_OBJECT(DR)         (DR)->object_info.base_object
 116 #define DR_TYPE(DR)                (DR)->type
 117 #define DR_ACCESS_FNS(DR)\
 118   (DR_TYPE(DR) == ARRAY_REF_TYPE ?  \
 119    (DR)->object_info.access_fns : (DR)->first_location.access_fns)
 120 #define DR_ACCESS_FN(DR, I)        VEC_index (tree, DR_ACCESS_FNS (DR), I)
 121 #define DR_NUM_DIMENSIONS(DR)      VEC_length (tree, DR_ACCESS_FNS (DR))
 122 #define DR_IS_READ(DR)             (DR)->is_read
 123 #define DR_BASE_ADDRESS(DR)        (DR)->first_location.base_address
 124 #define DR_OFFSET(DR)              (DR)->first_location.offset
 125 #define DR_INIT(DR)                (DR)->first_location.init
 126 #define DR_STEP(DR)                (DR)->first_location.step
 127 #define DR_MEMTAG(DR)              (DR)->memtag
 128 #define DR_ALIGNED_TO(DR)          (DR)->aligned_to
 129 #define DR_OFFSET_MISALIGNMENT(DR) (DR)->misalignment
 130 #define DR_PTR_INFO(DR)            (DR)->ptr_info
 131 #define DR_SUBVARS(DR)             (DR)->subvars
 132
 133 #define DR_ACCESS_FNS_ADDR(DR)       \
 134   (DR_TYPE(DR) == ARRAY_REF_TYPE ?   \
 135    &((DR)->object_info.access_fns) : &((DR)->first_location.access_fns))
 136 #define DR_SET_ACCESS_FNS(DR, ACC_FNS)         \
 137 {                                              \
 138   if (DR_TYPE(DR) == ARRAY_REF_TYPE)           \
 139     (DR)->object_info.access_fns = ACC_FNS;    \
 140   else                                         \
 141     (DR)->first_location.access_fns = ACC_FNS; \
 142 }
 143 #define DR_FREE_ACCESS_FNS(DR)                              \
 144 {                                                           \
 145   if (DR_TYPE(DR) == ARRAY_REF_TYPE)                        \
 146     VEC_free (tree, heap, (DR)->object_info.access_fns);    \
 147   else                                                      \
 148     VEC_free (tree, heap, (DR)->first_location.access_fns); \
 149 }
 150
 151 enum data_dependence_direction {
 152   dir_positive,
 153   dir_negative,
 154   dir_equal,
 155   dir_positive_or_negative,
 156   dir_positive_or_equal,
 157   dir_negative_or_equal,
 158   dir_star,
 159   dir_independent
 160 };
 161
 162 /* What is a subscript?  Given two array accesses a subscript is the
 163    tuple composed of the access functions for a given dimension.
 164    Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three
 165    subscripts: (f1, g1), (f2, g2), (f3, g3).  These three subscripts
 166    are stored in the data_dependence_relation structure under the form
 167    of an array of subscripts.  */
 168
 169 struct subscript
 170 {
 171   /* A description of the iterations for which the elements are
 172      accessed twice.  */
 173   tree conflicting_iterations_in_a;
 174   tree conflicting_iterations_in_b;
 175
 176   /* This field stores the information about the iteration domain
 177      validity of the dependence relation.  */
 178   tree last_conflict;
 179
 180   /* Distance from the iteration that access a conflicting element in
 181      A to the iteration that access this same conflicting element in
 182      B.  The distance is a tree scalar expression, i.e. a constant or a
 183      symbolic expression, but certainly not a chrec function.  */
 184   tree distance;
 185 };
 186
 187 typedef struct subscript *subscript_p;
 188 DEF_VEC_P(subscript_p);
 189 DEF_VEC_ALLOC_P (subscript_p, heap);
 190
 191 #define SUB_CONFLICTS_IN_A(SUB) SUB->conflicting_iterations_in_a
 192 #define SUB_CONFLICTS_IN_B(SUB) SUB->conflicting_iterations_in_b
 193 #define SUB_LAST_CONFLICT(SUB) SUB->last_conflict
 194 #define SUB_DISTANCE(SUB) SUB->distance
 195
 196 typedef struct loop *loop_p;
 197 DEF_VEC_P(loop_p);
 198 DEF_VEC_ALLOC_P (loop_p, heap);
 199
 200 /* A data_dependence_relation represents a relation between two
 201    data_references A and B.  */
 202
 203 struct data_dependence_relation
 204 {
 205
 206   struct data_reference *a;
 207   struct data_reference *b;
 208
 209   /* When the dependence relation is affine, it can be represented by
 210      a distance vector.  */
 211   bool affine_p;
 212
 213   /* A "yes/no/maybe" field for the dependence relation:
 214
 215      - when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
 216        relation between A and B, and the description of this relation
 217        is given in the SUBSCRIPTS array,
 218
 219      - when "ARE_DEPENDENT == chrec_known", there is no dependence and
 220        SUBSCRIPTS is empty,
 221
 222      - when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence,
 223        but the analyzer cannot be more specific.  */
 224   tree are_dependent;
 225
 226   /* For each subscript in the dependence test, there is an element in
 227      this array.  This is the attribute that labels the edge A->B of
 228      the data_dependence_relation.  */
 229   VEC (subscript_p, heap) *subscripts;
 230
 231   /* The analyzed loop nest.  */
 232   VEC (loop_p, heap) *loop_nest;
 233
 234   /* The classic direction vector.  */
 235   VEC (lambda_vector, heap) *dir_vects;
 236
 237   /* The classic distance vector.  */
 238   VEC (lambda_vector, heap) *dist_vects;
 239 };
 240
 241 typedef struct data_dependence_relation *ddr_p;
 242 DEF_VEC_P(ddr_p);
 243 DEF_VEC_ALLOC_P(ddr_p,heap);
 244
 245 #define DDR_A(DDR) DDR->a
 246 #define DDR_B(DDR) DDR->b
 247 #define DDR_AFFINE_P(DDR) DDR->affine_p
 248 #define DDR_ARE_DEPENDENT(DDR) DDR->are_dependent
 249 #define DDR_SUBSCRIPTS(DDR) DDR->subscripts
 250 #define DDR_SUBSCRIPT(DDR, I) VEC_index (subscript_p, DDR_SUBSCRIPTS (DDR), I)
 251 #define DDR_NUM_SUBSCRIPTS(DDR) VEC_length (subscript_p, DDR_SUBSCRIPTS (DDR))
 252
 253 #define DDR_LOOP_NEST(DDR) DDR->loop_nest
 254 /* The size of the direction/distance vectors: the number of loops in
 255    the loop nest.  */
 256 #define DDR_NB_LOOPS(DDR) (VEC_length (loop_p, DDR_LOOP_NEST (DDR)))
 257
 258 #define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects)
 259 #define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects)
 260 #define DDR_NUM_DIST_VECTS(DDR) \
 261   (VEC_length (lambda_vector, DDR_DIST_VECTS (DDR)))
 262 #define DDR_NUM_DIR_VECTS(DDR) \
 263   (VEC_length (lambda_vector, DDR_DIR_VECTS (DDR)))
 264 #define DDR_DIR_VECT(DDR, I) \
 265   VEC_index (lambda_vector, DDR_DIR_VECTS (DDR), I)
 266 #define DDR_DIST_VECT(DDR, I) \
 267   VEC_index (lambda_vector, DDR_DIST_VECTS (DDR), I)
 268
 269 \f
 270
 271 extern tree find_data_references_in_loop (struct loop *,
 272                                           VEC (data_reference_p, heap) **);
 273 extern void compute_data_dependences_for_loop (struct loop *, bool,
 274                                                VEC (data_reference_p, heap) **,
 275                                                VEC (ddr_p, heap) **);
 276 extern void print_direction_vector (FILE *, lambda_vector, int);
 277 extern void print_dir_vectors (FILE *, VEC (lambda_vector, heap) *, int);
 278 extern void print_dist_vectors (FILE *, VEC (lambda_vector, heap) *, int);
 279 extern void dump_subscript (FILE *, struct subscript *);
 280 extern void dump_ddrs (FILE *, VEC (ddr_p, heap) *);
 281 extern void dump_dist_dir_vectors (FILE *, VEC (ddr_p, heap) *);
 282 extern void dump_data_reference (FILE *, struct data_reference *);
 283 extern void dump_data_references (FILE *, VEC (data_reference_p, heap) *);
 284 extern void debug_data_dependence_relation (struct data_dependence_relation *);
 285 extern void dump_data_dependence_relation (FILE *,
 286                                            struct data_dependence_relation *);
 287 extern void dump_data_dependence_relations (FILE *, VEC (ddr_p, heap) *);
 288 extern void dump_data_dependence_direction (FILE *,
 289                                             enum data_dependence_direction);
 290 extern void free_dependence_relation (struct data_dependence_relation *);
 291 extern void free_dependence_relations (VEC (ddr_p, heap) *);
 292 extern void free_data_refs (VEC (data_reference_p, heap) *);
 293 extern struct data_reference *analyze_array (tree, tree, bool);
 294 extern void estimate_iters_using_array (tree, tree);
 295
 296
 297 /* Return the index of the variable VAR in the LOOP_NEST array.  */
 298
 299 static inline int
 300 index_in_loop_nest (int var, VEC (loop_p, heap) *loop_nest)
 301 {
 302   struct loop *loopi;
 303   int var_index;
 304
 305   for (var_index = 0; VEC_iterate (loop_p, loop_nest, var_index, loopi);
 306        var_index++)
 307     if (loopi->num == var)
 308       break;
 309
 310   return var_index;
 311 }
 312
 313 /* In lambda-code.c  */
 314 bool lambda_transform_legal_p (lambda_trans_matrix, int, VEC (ddr_p, heap) *);
 315
 316 #endif  /* GCC_TREE_DATA_REF_H  */