gcc/ipa-fnsummary.h

   1 /* IPA function body analysis.
   2    Copyright (C) 2003-2018 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 wen there is only one caller of the function before small function
 102      inlining.  */
 103   unsigned int single_caller : 1;
 104   /* True if function contains any floating point expressions.  */
 105   unsigned int fp_expressions : 1;
 106
 107   /* Information about function that will result after applying all the
 108      inline decisions present in the callgraph.  Generally kept up to
 109      date only for functions that are not inline clones. */
 110
 111   /* Estimated stack frame consumption by the function.  */
 112   HOST_WIDE_INT estimated_stack_size;
 113   /* Expected offset of the stack frame of function.  */
 114   HOST_WIDE_INT stack_frame_offset;
 115   /* Estimated size of the function after inlining.  */
 116   sreal GTY((skip)) time;
 117   int size;
 118
 119   /* Conditional size/time information.  The summaries are being
 120      merged during inlining.  */
 121   conditions conds;
 122   vec<size_time_entry, va_gc> *size_time_table;
 123
 124   /* Predicate on when some loop in the function becomes to have known
 125      bounds.   */
 126   predicate * GTY((skip)) loop_iterations;
 127   /* Predicate on when some loop in the function becomes to have known
 128      stride.   */
 129   predicate * GTY((skip)) loop_stride;
 130   /* Predicate on when some array indexes become constants.  */
 131   predicate * GTY((skip)) array_index;
 132   /* Estimated growth for inlining all copies of the function before start
 133      of small functions inlining.
 134      This value will get out of date as the callers are duplicated, but
 135      using up-to-date value in the badness metric mean a lot of extra
 136      expenses.  */
 137   int growth;
 138   /* Number of SCC on the beginning of inlining process.  */
 139   int scc_no;
 140
 141   /* Keep all field empty so summary dumping works during its computation.
 142      This is useful for debugging.  */
 143   ipa_fn_summary ()
 144     : estimated_self_stack_size (0), self_size (0), min_size (0),
 145       inlinable (false), single_caller (false),
 146       fp_expressions (false), estimated_stack_size (false),
 147       stack_frame_offset (false), time (0), size (0), conds (NULL),
 148       size_time_table (NULL), loop_iterations (NULL), loop_stride (NULL),
 149       array_index (NULL), growth (0), scc_no (0)
 150     {
 151     }
 152
 153   /* Record time and size under given predicates.  */
 154   void account_size_time (int, sreal, const predicate &, const predicate &);
 155
 156   /* Reset summary to empty state.  */
 157   void reset (struct cgraph_node *node);
 158
 159   /* We keep values scaled up, so fractional sizes can be accounted.  */
 160   static const int size_scale = 2;
 161 };
 162
 163 class GTY((user)) ipa_fn_summary_t: public function_summary <ipa_fn_summary *>
 164 {
 165 public:
 166   ipa_fn_summary_t (symbol_table *symtab, bool ggc):
 167     function_summary <ipa_fn_summary *> (symtab, ggc) {}
 168
 169   static ipa_fn_summary_t *create_ggc (symbol_table *symtab)
 170   {
 171     struct ipa_fn_summary_t *summary = new (ggc_alloc <ipa_fn_summary_t> ())
 172       ipa_fn_summary_t(symtab, true);
 173     summary->disable_insertion_hook ();
 174     return summary;
 175   }
 176
 177
 178   virtual void insert (cgraph_node *, ipa_fn_summary *);
 179   virtual void remove (cgraph_node *node, ipa_fn_summary *);
 180   virtual void duplicate (cgraph_node *src, cgraph_node *dst,
 181                           ipa_fn_summary *src_data, ipa_fn_summary *dst_data);
 182 };
 183
 184 extern GTY(()) function_summary <ipa_fn_summary *> *ipa_fn_summaries;
 185
 186 /* Information kept about callgraph edges.  */
 187 struct ipa_call_summary
 188 {
 189   class predicate *predicate;
 190   /* Vector indexed by parameters.  */
 191   vec<inline_param_summary> param;
 192   /* Estimated size and time of the call statement.  */
 193   int call_stmt_size;
 194   int call_stmt_time;
 195   /* Depth of loop nest, 0 means no nesting.  */
 196   unsigned int loop_depth;
 197   /* Indicates whether the caller returns the value of it's callee.  */
 198   bool is_return_callee_uncaptured;
 199
 200   /* Keep all field empty so summary dumping works during its computation.
 201      This is useful for debugging.  */
 202   ipa_call_summary ()
 203     : predicate (NULL), param (vNULL), call_stmt_size (0), call_stmt_time (0),
 204       loop_depth (0)
 205     {
 206     }
 207
 208   /* Reset inline summary to empty state.  */
 209   void reset ();
 210 };
 211
 212 class ipa_call_summary_t: public call_summary <ipa_call_summary *>
 213 {
 214 public:
 215   ipa_call_summary_t (symbol_table *symtab, bool ggc):
 216     call_summary <ipa_call_summary *> (symtab, ggc) {}
 217
 218   /* Hook that is called by summary when an edge is duplicated.  */
 219   virtual void remove (cgraph_edge *cs, ipa_call_summary *);
 220   /* Hook that is called by summary when an edge is duplicated.  */
 221   virtual void duplicate (cgraph_edge *src, cgraph_edge *dst,
 222                           ipa_call_summary *src_data,
 223                           ipa_call_summary *dst_data);
 224 };
 225
 226 extern call_summary <ipa_call_summary *> *ipa_call_summaries;
 227
 228 /* In ipa-fnsummary.c  */
 229 void ipa_debug_fn_summary (struct cgraph_node *);
 230 void ipa_dump_fn_summaries (FILE *f);
 231 void ipa_dump_fn_summary (FILE *f, struct cgraph_node *node);
 232 void ipa_dump_hints (FILE *f, ipa_hints);
 233 void ipa_free_fn_summary (void);
 234 void inline_analyze_function (struct cgraph_node *node);
 235 void estimate_ipcp_clone_size_and_time (struct cgraph_node *,
 236                                         vec<tree>,
 237                                         vec<ipa_polymorphic_call_context>,
 238                                         vec<ipa_agg_jump_function_p>,
 239                                         int *, sreal *, sreal *,
 240                                         ipa_hints *);
 241 void ipa_merge_fn_summary_after_inlining (struct cgraph_edge *edge);
 242 void ipa_update_overall_fn_summary (struct cgraph_node *node);
 243 void compute_fn_summary (struct cgraph_node *, bool);
 244
 245
 246 void evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 247                                    clause_t *clause_ptr,
 248                                    clause_t *nonspec_clause_ptr,
 249                                    vec<tree> *known_vals_ptr,
 250                                    vec<ipa_polymorphic_call_context>
 251                                    *known_contexts_ptr,
 252                                    vec<ipa_agg_jump_function_p> *);
 253 void estimate_node_size_and_time (struct cgraph_node *node,
 254                                   clause_t possible_truths,
 255                                   clause_t nonspec_possible_truths,
 256                                   vec<tree> known_vals,
 257                                   vec<ipa_polymorphic_call_context>,
 258                                   vec<ipa_agg_jump_function_p> known_aggs,
 259                                   int *ret_size, int *ret_min_size,
 260                                   sreal *ret_time,
 261                                   sreal *ret_nonspecialized_time,
 262                                   ipa_hints *ret_hints,
 263                                   vec<inline_param_summary>
 264                                   inline_param_summary);
 265
 266 void ipa_fnsummary_c_finalize (void);
 267
 268 #endif /* GCC_IPA_FNSUMMARY_H */