gcc/tree-data-ref.h

   1 /* Data references and dependences detectors.
   2    Copyright (C) 2003, 2004, 2005, 2006 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 2, 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 COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22 #ifndef GCC_TREE_DATA_REF_H
  23 #define GCC_TREE_DATA_REF_H
  24
  25 #include "lambda.h"
  26
  27 /** {base_address + offset + init} is the first location accessed by data-ref
  28       in the loop, and step is the stride of data-ref in the loop in bytes;
  29       e.g.:
  30
  31                        Example 1                      Example 2
  32       data-ref         a[j].b[i][j]                   a + x + 16B (a is int*)
  33
  34 First location info:
  35       base_address     &a                             a
  36       offset           j_0*D_j + i_0*D_i + C_a        x
  37       init             C_b                            16
  38       step             D_j                            4
  39       access_fn        NULL                           {16, +, 1}
  40
  41 Base object info:
  42       base_object      a                              NULL
  43       access_fn        <access_fns of indexes of b>   NULL
  44
  45   **/
  46 struct first_location_in_loop
  47 {
  48   tree base_address;
  49   tree offset;
  50   tree init;
  51   tree step;
  52   /* Access function related to first location in the loop.  */
  53   VEC(tree,heap) *access_fns;
  54
  55 };
  56
  57 struct base_object_info
  58 {
  59   /* The object.  */
  60   tree base_object;
  61
  62   /* A list of chrecs.  Access functions related to BASE_OBJECT.  */
  63   VEC(tree,heap) *access_fns;
  64 };
  65
  66 enum data_ref_type {
  67   ARRAY_REF_TYPE,
  68   POINTER_REF_TYPE
  69 };
  70
  71 struct data_reference
  72 {
  73   /* A pointer to the statement that contains this DR.  */
  74   tree stmt;
  75
  76   /* A pointer to the ARRAY_REF node.  */
  77   tree ref;
  78
  79   /* Auxiliary info specific to a pass.  */
  80   int aux;
  81
  82   /* True when the data reference is in RHS of a stmt.  */
  83   bool is_read;
  84
  85   /* First location accessed by the data-ref in the loop.  */
  86   struct first_location_in_loop first_location;
  87
  88   /* Base object related info.  */
  89   struct base_object_info object_info;
  90
  91   /* Aliasing information.  This field represents the symbol that
  92      should be aliased by a pointer holding the address of this data
  93      reference.  If the original data reference was a pointer
  94      dereference, then this field contains the memory tag that should
  95      be used by the new vector-pointer.  */
  96   tree memtag;
  97   struct ptr_info_def *ptr_info;
  98   subvar_t subvars;
  99
 100   /* Alignment information.  */
 101   /* The offset of the data-reference from its base in bytes.  */
 102   tree misalignment;
 103   /* The maximum data-ref's alignment.  */
 104   tree aligned_to;
 105
 106   /* The type of the data-ref.  */
 107   enum data_ref_type type;
 108 };
 109
 110 #define DR_STMT(DR)                (DR)->stmt
 111 #define DR_REF(DR)                 (DR)->ref
 112 #define DR_BASE_OBJECT(DR)         (DR)->object_info.base_object
 113 #define DR_TYPE(DR)                (DR)->type
 114 #define DR_ACCESS_FNS(DR)\
 115   (DR_TYPE(DR) == ARRAY_REF_TYPE ?  \
 116    (DR)->object_info.access_fns : (DR)->first_location.access_fns)
 117 #define DR_ACCESS_FN(DR, I)        VEC_index (tree, DR_ACCESS_FNS (DR), I)
 118 #define DR_NUM_DIMENSIONS(DR)      VEC_length (tree, DR_ACCESS_FNS (DR))
 119 #define DR_IS_READ(DR)             (DR)->is_read
 120 #define DR_BASE_ADDRESS(DR)        (DR)->first_location.base_address
 121 #define DR_OFFSET(DR)              (DR)->first_location.offset
 122 #define DR_INIT(DR)                (DR)->first_location.init
 123 #define DR_STEP(DR)                (DR)->first_location.step
 124 #define DR_MEMTAG(DR)              (DR)->memtag
 125 #define DR_ALIGNED_TO(DR)          (DR)->aligned_to
 126 #define DR_OFFSET_MISALIGNMENT(DR) (DR)->misalignment
 127 #define DR_PTR_INFO(DR)            (DR)->ptr_info
 128 #define DR_SUBVARS(DR)             (DR)->subvars
 129
 130 #define DR_ACCESS_FNS_ADDR(DR)       \
 131   (DR_TYPE(DR) == ARRAY_REF_TYPE ?   \
 132    &((DR)->object_info.access_fns) : &((DR)->first_location.access_fns))
 133 #define DR_SET_ACCESS_FNS(DR, ACC_FNS)         \
 134 {                                              \
 135   if (DR_TYPE(DR) == ARRAY_REF_TYPE)           \
 136     (DR)->object_info.access_fns = ACC_FNS;    \
 137   else                                         \
 138     (DR)->first_location.access_fns = ACC_FNS; \
 139 }
 140 #define DR_FREE_ACCESS_FNS(DR)                              \
 141 {                                                           \
 142   if (DR_TYPE(DR) == ARRAY_REF_TYPE)                        \
 143     VEC_free (tree, heap, (DR)->object_info.access_fns);    \
 144   else                                                      \
 145     VEC_free (tree, heap, (DR)->first_location.access_fns); \
 146 }
 147
 148 enum data_dependence_direction {
 149   dir_positive,
 150   dir_negative,
 151   dir_equal,
 152   dir_positive_or_negative,
 153   dir_positive_or_equal,
 154   dir_negative_or_equal,
 155   dir_star,
 156   dir_independent
 157 };
 158
 159 /* What is a subscript?  Given two array accesses a subscript is the
 160    tuple composed of the access functions for a given dimension.
 161    Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three
 162    subscripts: (f1, g1), (f2, g2), (f3, g3).  These three subscripts
 163    are stored in the data_dependence_relation structure under the form
 164    of an array of subscripts.  */
 165
 166 struct subscript
 167 {
 168   /* A description of the iterations for which the elements are
 169      accessed twice.  */
 170   tree conflicting_iterations_in_a;
 171   tree conflicting_iterations_in_b;
 172
 173   /* This field stores the information about the iteration domain
 174      validity of the dependence relation.  */
 175   tree last_conflict;
 176
 177   /* Distance from the iteration that access a conflicting element in
 178      A to the iteration that access this same conflicting element in
 179      B.  The distance is a tree scalar expression, i.e. a constant or a
 180      symbolic expression, but certainly not a chrec function.  */
 181   tree distance;
 182 };
 183
 184 #define SUB_CONFLICTS_IN_A(SUB) SUB->conflicting_iterations_in_a
 185 #define SUB_CONFLICTS_IN_B(SUB) SUB->conflicting_iterations_in_b
 186 #define SUB_LAST_CONFLICT(SUB) SUB->last_conflict
 187 #define SUB_DISTANCE(SUB) SUB->distance
 188
 189 /* A data_dependence_relation represents a relation between two
 190    data_references A and B.  */
 191
 192 struct data_dependence_relation
 193 {
 194
 195   struct data_reference *a;
 196   struct data_reference *b;
 197
 198   /* When the dependence relation is affine, it can be represented by
 199      a distance vector.  */
 200   bool affine_p;
 201
 202   /* A "yes/no/maybe" field for the dependence relation:
 203
 204      - when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
 205        relation between A and B, and the description of this relation
 206        is given in the SUBSCRIPTS array,
 207
 208      - when "ARE_DEPENDENT == chrec_known", there is no dependence and
 209        SUBSCRIPTS is empty,
 210
 211      - when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence,
 212        but the analyzer cannot be more specific.  */
 213   tree are_dependent;
 214
 215   /* For each subscript in the dependence test, there is an element in
 216      this array.  This is the attribute that labels the edge A->B of
 217      the data_dependence_relation.  */
 218   varray_type subscripts;
 219
 220   /* The size of the direction/distance vectors: the depth of the
 221      analyzed loop nest.  */
 222   int size_vect;
 223
 224   /* The classic direction vector.  */
 225   VEC(lambda_vector,heap) *dir_vects;
 226
 227   /* The classic distance vector.  */
 228   VEC(lambda_vector,heap) *dist_vects;
 229 };
 230
 231 typedef struct data_dependence_relation *ddr_p;
 232 DEF_VEC_P(ddr_p);
 233 DEF_VEC_ALLOC_P(ddr_p,heap);
 234
 235 #define DDR_A(DDR) DDR->a
 236 #define DDR_B(DDR) DDR->b
 237 #define DDR_AFFINE_P(DDR) DDR->affine_p
 238 #define DDR_ARE_DEPENDENT(DDR) DDR->are_dependent
 239 #define DDR_SUBSCRIPTS(DDR) DDR->subscripts
 240 #define DDR_SUBSCRIPTS_VECTOR_INIT(DDR, N) \
 241   VARRAY_GENERIC_PTR_INIT (DDR_SUBSCRIPTS (DDR), N, "subscripts_vector");
 242 #define DDR_SUBSCRIPT(DDR, I) VARRAY_GENERIC_PTR (DDR_SUBSCRIPTS (DDR), I)
 243 #define DDR_NUM_SUBSCRIPTS(DDR) VARRAY_ACTIVE_SIZE (DDR_SUBSCRIPTS (DDR))
 244 #define DDR_SIZE_VECT(DDR) DDR->size_vect
 245
 246 #define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects)
 247 #define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects)
 248 #define DDR_NUM_DIST_VECTS(DDR) \
 249   (VEC_length (lambda_vector, DDR_DIST_VECTS (DDR)))
 250 #define DDR_NUM_DIR_VECTS(DDR) \
 251   (VEC_length (lambda_vector, DDR_DIR_VECTS (DDR)))
 252 #define DDR_DIR_VECT(DDR, I) \
 253   VEC_index (lambda_vector, DDR_DIR_VECTS (DDR), I)
 254 #define DDR_DIST_VECT(DDR, I) \
 255   VEC_index (lambda_vector, DDR_DIST_VECTS (DDR), I)
 256
 257 \f
 258
 259 extern tree find_data_references_in_loop (struct loop *, varray_type *);
 260 extern void compute_data_dependences_for_loop (struct loop *, bool,
 261                                                varray_type *, varray_type *);
 262 extern void print_direction_vector (FILE *, lambda_vector, int);
 263 extern void dump_subscript (FILE *, struct subscript *);
 264 extern void dump_ddrs (FILE *, varray_type);
 265 extern void dump_dist_dir_vectors (FILE *, varray_type);
 266 extern void dump_data_reference (FILE *, struct data_reference *);
 267 extern void dump_data_references (FILE *, varray_type);
 268 extern void dump_data_dependence_relation (FILE *,
 269                                            struct data_dependence_relation *);
 270 extern void dump_data_dependence_relations (FILE *, varray_type);
 271 extern void dump_data_dependence_direction (FILE *,
 272                                             enum data_dependence_direction);
 273 extern void free_dependence_relation (struct data_dependence_relation *);
 274 extern void free_dependence_relations (varray_type);
 275 extern void free_data_refs (varray_type);
 276 extern struct data_reference *analyze_array (tree, tree, bool);
 277 extern void estimate_iters_using_array (tree, tree);
 278
 279 \f
 280
 281 #endif  /* GCC_TREE_DATA_REF_H  */