gcc/ipa-fnsummary.h

   1 /* IPA function body analysis.
   2    Copyright (C) 2003-2017 Free Software Foundation, Inc.
   3    Contributed by Jan Hubicka
   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_IPA_SUMMARY_H
  22 #define GCC_IPA_SUMMARY_H
  23
  24 #include "sreal.h"
  25 #include "ipa-predicate.h"
  26
  27
  28 /* Hints are reasons why IPA heuristics should preffer specializing given
  29    function.  They are represtented as bitmap of the following values.  */
  30 enum ipa_hints_vals {
  31   /* When specialization turns indirect call into a direct call,
  32      it is good idea to do so.  */
  33   INLINE_HINT_indirect_call = 1,
  34   /* Inlining may make loop iterations or loop stride known.  It is good idea
  35      to do so because it enables loop optimizatoins.  */
  36   INLINE_HINT_loop_iterations = 2,
  37   INLINE_HINT_loop_stride = 4,
  38   /* Inlining within same strongly connected component of callgraph is often
  39      a loss due to increased stack frame usage and prologue setup costs.  */
  40   INLINE_HINT_same_scc = 8,
  41   /* Inlining functions in strongly connected component is not such a great
  42      win.  */
  43   INLINE_HINT_in_scc = 16,
  44   /* If function is declared inline by user, it may be good idea to inline
  45      it.  Set by simple_edge_hints in ipa-inline-analysis.c.  */
  46   INLINE_HINT_declared_inline = 32,
  47   /* Programs are usually still organized for non-LTO compilation and thus
  48      if functions are in different modules, inlining may not be so important.
  49      Set by simple_edge_hints in ipa-inline-analysis.c.   */
  50   INLINE_HINT_cross_module = 64,
  51   /* If array indexes of loads/stores become known there may be room for
  52      further optimization.  */
  53   INLINE_HINT_array_index = 128,
  54   /* We know that the callee is hot by profile.  */
  55   INLINE_HINT_known_hot = 256
  56 };
  57
  58 typedef int ipa_hints;
  59
  60 /* Simple description of whether a memory load or a condition refers to a load
  61    from an aggregate and if so, how and where from in the aggregate.
  62    Individual fields have the same meaning like fields with the same name in
  63    struct condition.  */
  64
  65 struct agg_position_info
  66 {
  67   HOST_WIDE_INT offset;
  68   bool agg_contents;
  69   bool by_ref;
  70 };
  71
  72 /* Representation of function body size and time depending on the call
  73    context.  We keep simple array of record, every containing of predicate
  74    and time/size to account.  */
  75 struct GTY(()) size_time_entry
  76 {
  77   /* Predicate for code to be executed.  */
  78   predicate exec_predicate;
  79   /* Predicate for value to be constant and optimized out in a specialized copy.
  80      When deciding on specialization this makes it possible to see how much
  81      the executed code paths will simplify.  */
  82   predicate nonconst_predicate;
  83   int size;
  84   sreal GTY((skip)) time;
  85 };
  86
  87 /* Function inlining information.  */
  88 struct GTY(()) ipa_fn_summary
  89 {
  90   /* Information about the function body itself.  */
  91
  92   /* Estimated stack frame consumption by the function.  */
  93   HOST_WIDE_INT estimated_self_stack_size;
  94   /* Size of the function body.  */
  95   int self_size;
  96   /* Minimal size increase after inlining.  */
  97   int min_size;
  98
  99   /* False when there something makes inlining impossible (such as va_arg).  */
 100   unsigned inlinable : 1;
 101   /* True when function contains cilk spawn (and thus we can not inline
 102      into it).  */
 103   unsigned contains_cilk_spawn : 1;
 104   /* True wen there is only one caller of the function before small function
 105      inlining.  */
 106   unsigned int single_caller : 1;
 107   /* True if function contains any floating point expressions.  */
 108   unsigned int fp_expressions : 1;
 109
 110   /* Information about function that will result after applying all the
 111      inline decisions present in the callgraph.  Generally kept up to
 112      date only for functions that are not inline clones. */
 113
 114   /* Estimated stack frame consumption by the function.  */
 115   HOST_WIDE_INT estimated_stack_size;
 116   /* Expected offset of the stack frame of function.  */
 117   HOST_WIDE_INT stack_frame_offset;
 118   /* Estimated size of the function after inlining.  */
 119   sreal GTY((skip)) time;
 120   int size;
 121
 122   /* Conditional size/time information.  The summaries are being
 123      merged during inlining.  */
 124   conditions conds;
 125   vec<size_time_entry, va_gc> *size_time_table;
 126
 127   /* Predicate on when some loop in the function becomes to have known
 128      bounds.   */
 129   predicate * GTY((skip)) loop_iterations;
 130   /* Predicate on when some loop in the function becomes to have known
 131      stride.   */
 132   predicate * GTY((skip)) loop_stride;
 133   /* Predicate on when some array indexes become constants.  */
 134   predicate * GTY((skip)) array_index;
 135   /* Estimated growth for inlining all copies of the function before start
 136      of small functions inlining.
 137      This value will get out of date as the callers are duplicated, but
 138      using up-to-date value in the badness metric mean a lot of extra
 139      expenses.  */
 140   int growth;
 141   /* Number of SCC on the beginning of inlining process.  */
 142   int scc_no;
 143
 144   /* Keep all field empty so summary dumping works during its computation.
 145      This is useful for debugging.  */
 146   ipa_fn_summary ()
 147     : estimated_self_stack_size (0), self_size (0), min_size (0),
 148       inlinable (false), contains_cilk_spawn (false), single_caller (false),
 149       fp_expressions (false), estimated_stack_size (false),
 150       stack_frame_offset (false), time (0), size (0), conds (NULL),
 151       size_time_table (NULL), loop_iterations (NULL), loop_stride (NULL),
 152       array_index (NULL), growth (0), scc_no (0)
 153     {
 154     }
 155
 156   /* Record time and size under given predicates.  */
 157   void account_size_time (int, sreal, const predicate &, const predicate &);
 158
 159   /* Reset summary to empty state.  */
 160   void reset (struct cgraph_node *node);
 161
 162   /* We keep values scaled up, so fractional sizes can be accounted.  */
 163   static const int size_scale = 2;
 164 };
 165
 166 class GTY((user)) ipa_fn_summary_t: public function_summary <ipa_fn_summary *>
 167 {
 168 public:
 169   ipa_fn_summary_t (symbol_table *symtab, bool ggc):
 170     function_summary <ipa_fn_summary *> (symtab, ggc) {}
 171
 172   static ipa_fn_summary_t *create_ggc (symbol_table *symtab)
 173   {
 174     struct ipa_fn_summary_t *summary = new (ggc_alloc <ipa_fn_summary_t> ())
 175       ipa_fn_summary_t(symtab, true);
 176     summary->disable_insertion_hook ();
 177     return summary;
 178   }
 179
 180
 181   virtual void insert (cgraph_node *, ipa_fn_summary *);
 182   virtual void remove (cgraph_node *node, ipa_fn_summary *);
 183   virtual void duplicate (cgraph_node *src, cgraph_node *dst,
 184                           ipa_fn_summary *src_data, ipa_fn_summary *dst_data);
 185 };
 186
 187 extern GTY(()) function_summary <ipa_fn_summary *> *ipa_fn_summaries;
 188
 189 /* Information kept about callgraph edges.  */
 190 struct ipa_call_summary
 191 {
 192   class predicate *predicate;
 193   /* Vector indexed by parameters.  */
 194   vec<inline_param_summary> param;
 195   /* Estimated size and time of the call statement.  */
 196   int call_stmt_size;
 197   int call_stmt_time;
 198   /* Depth of loop nest, 0 means no nesting.  */
 199   unsigned int loop_depth;
 200
 201   /* Keep all field empty so summary dumping works during its computation.
 202      This is useful for debugging.  */
 203   ipa_call_summary ()
 204     : predicate (NULL), param (vNULL), call_stmt_size (0), call_stmt_time (0),
 205       loop_depth (0)
 206     {
 207     }
 208
 209   /* Reset inline summary to empty state.  */
 210   void reset ();
 211 };
 212
 213 class ipa_call_summary_t: public call_summary <ipa_call_summary *>
 214 {
 215 public:
 216   ipa_call_summary_t (symbol_table *symtab, bool ggc):
 217     call_summary <ipa_call_summary *> (symtab, ggc) {}
 218
 219   /* Hook that is called by summary when an edge is duplicated.  */
 220   virtual void remove (cgraph_edge *cs, ipa_call_summary *);
 221   /* Hook that is called by summary when an edge is duplicated.  */
 222   virtual void duplicate (cgraph_edge *src, cgraph_edge *dst,
 223                           ipa_call_summary *src_data,
 224                           ipa_call_summary *dst_data);
 225 };
 226
 227 extern call_summary <ipa_call_summary *> *ipa_call_summaries;
 228
 229 /* In ipa-fnsummary.c  */
 230 void ipa_debug_fn_summary (struct cgraph_node *);
 231 void ipa_dump_fn_summaries (FILE *f);
 232 void ipa_dump_fn_summary (FILE *f, struct cgraph_node *node);
 233 void ipa_dump_hints (FILE *f, ipa_hints);
 234 void ipa_free_fn_summary (void);
 235 void inline_analyze_function (struct cgraph_node *node);
 236 void estimate_ipcp_clone_size_and_time (struct cgraph_node *,
 237                                         vec<tree>,
 238                                         vec<ipa_polymorphic_call_context>,
 239                                         vec<ipa_agg_jump_function_p>,
 240                                         int *, sreal *, sreal *,
 241                                         ipa_hints *);
 242 void ipa_merge_fn_summary_after_inlining (struct cgraph_edge *edge);
 243 void ipa_update_overall_fn_summary (struct cgraph_node *node);
 244 void compute_fn_summary (struct cgraph_node *, bool);
 245
 246
 247 void evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 248                                    clause_t *clause_ptr,
 249                                    clause_t *nonspec_clause_ptr,
 250                                    vec<tree> *known_vals_ptr,
 251                                    vec<ipa_polymorphic_call_context>
 252                                    *known_contexts_ptr,
 253                                    vec<ipa_agg_jump_function_p> *);
 254 void estimate_node_size_and_time (struct cgraph_node *node,
 255                                   clause_t possible_truths,
 256                                   clause_t nonspec_possible_truths,
 257                                   vec<tree> known_vals,
 258                                   vec<ipa_polymorphic_call_context>,
 259                                   vec<ipa_agg_jump_function_p> known_aggs,
 260                                   int *ret_size, int *ret_min_size,
 261                                   sreal *ret_time,
 262                                   sreal *ret_nonspecialized_time,
 263                                   ipa_hints *ret_hints,
 264                                   vec<inline_param_summary>
 265                                   inline_param_summary);
 266
 267 #endif /* GCC_IPA_FNSUMMARY_H */