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   /* Keep all field empty so summary dumping works during its computation.
  91      This is useful for debugging.  */
  92   ipa_fn_summary ()
  93     : estimated_self_stack_size (0), self_size (0), min_size (0),
  94       inlinable (false), single_caller (false),
  95       fp_expressions (false), estimated_stack_size (false),
  96       stack_frame_offset (false), time (0), size (0), conds (NULL),
  97       size_time_table (NULL), loop_iterations (NULL), loop_stride (NULL),
  98       array_index (NULL), growth (0), scc_no (0)
  99   {
 100   }
 101
 102   /* Copy constructor.  */
 103   ipa_fn_summary (const ipa_fn_summary &s)
 104     : estimated_self_stack_size (s.estimated_self_stack_size),
 105     self_size (s.self_size), min_size (s.min_size),
 106     inlinable (s.inlinable), single_caller (s.single_caller),
 107     fp_expressions (s.fp_expressions),
 108     estimated_stack_size (s.estimated_stack_size),
 109     stack_frame_offset (s.stack_frame_offset), time (s.time), size (s.size),
 110     conds (s.conds), size_time_table (s.size_time_table),
 111     loop_iterations (s.loop_iterations), loop_stride (s.loop_stride),
 112     array_index (s.array_index), growth (s.growth), scc_no (s.scc_no)
 113   {}
 114
 115   /* Default constructor.  */
 116   ~ipa_fn_summary ();
 117
 118   /* Information about the function body itself.  */
 119
 120   /* Estimated stack frame consumption by the function.  */
 121   HOST_WIDE_INT estimated_self_stack_size;
 122   /* Size of the function body.  */
 123   int self_size;
 124   /* Minimal size increase after inlining.  */
 125   int min_size;
 126
 127   /* False when there something makes inlining impossible (such as va_arg).  */
 128   unsigned inlinable : 1;
 129   /* True wen there is only one caller of the function before small function
 130      inlining.  */
 131   unsigned int single_caller : 1;
 132   /* True if function contains any floating point expressions.  */
 133   unsigned int fp_expressions : 1;
 134
 135   /* Information about function that will result after applying all the
 136      inline decisions present in the callgraph.  Generally kept up to
 137      date only for functions that are not inline clones. */
 138
 139   /* Estimated stack frame consumption by the function.  */
 140   HOST_WIDE_INT estimated_stack_size;
 141   /* Expected offset of the stack frame of function.  */
 142   HOST_WIDE_INT stack_frame_offset;
 143   /* Estimated size of the function after inlining.  */
 144   sreal GTY((skip)) time;
 145   int size;
 146
 147   /* Conditional size/time information.  The summaries are being
 148      merged during inlining.  */
 149   conditions conds;
 150   vec<size_time_entry, va_gc> *size_time_table;
 151
 152   /* Predicate on when some loop in the function becomes to have known
 153      bounds.   */
 154   predicate * GTY((skip)) loop_iterations;
 155   /* Predicate on when some loop in the function becomes to have known
 156      stride.   */
 157   predicate * GTY((skip)) loop_stride;
 158   /* Predicate on when some array indexes become constants.  */
 159   predicate * GTY((skip)) array_index;
 160   /* Estimated growth for inlining all copies of the function before start
 161      of small functions inlining.
 162      This value will get out of date as the callers are duplicated, but
 163      using up-to-date value in the badness metric mean a lot of extra
 164      expenses.  */
 165   int growth;
 166   /* Number of SCC on the beginning of inlining process.  */
 167   int scc_no;
 168
 169   /* Record time and size under given predicates.  */
 170   void account_size_time (int, sreal, const predicate &, const predicate &);
 171
 172   /* We keep values scaled up, so fractional sizes can be accounted.  */
 173   static const int size_scale = 2;
 174 };
 175
 176 class GTY((user)) ipa_fn_summary_t: public function_summary <ipa_fn_summary *>
 177 {
 178 public:
 179   ipa_fn_summary_t (symbol_table *symtab, bool ggc):
 180     function_summary <ipa_fn_summary *> (symtab, ggc) {}
 181
 182   static ipa_fn_summary_t *create_ggc (symbol_table *symtab)
 183   {
 184     struct ipa_fn_summary_t *summary = new (ggc_alloc <ipa_fn_summary_t> ())
 185       ipa_fn_summary_t(symtab, true);
 186     summary->disable_insertion_hook ();
 187     return summary;
 188   }
 189
 190   /* Remove ipa_fn_summary for all callees of NODE.  */
 191   void remove_callees (cgraph_node *node);
 192
 193   virtual void insert (cgraph_node *, ipa_fn_summary *);
 194   virtual void remove (cgraph_node *node, ipa_fn_summary *)
 195   {
 196     remove_callees (node);
 197   }
 198
 199   virtual void duplicate (cgraph_node *src, cgraph_node *dst,
 200                           ipa_fn_summary *src_data, ipa_fn_summary *dst_data);
 201 };
 202
 203 extern GTY(()) function_summary <ipa_fn_summary *> *ipa_fn_summaries;
 204
 205 /* Information kept about callgraph edges.  */
 206 struct ipa_call_summary
 207 {
 208   /* Keep all field empty so summary dumping works during its computation.
 209      This is useful for debugging.  */
 210   ipa_call_summary ()
 211     : predicate (NULL), param (vNULL), call_stmt_size (0), call_stmt_time (0),
 212       loop_depth (0), is_return_callee_uncaptured (false)
 213     {
 214     }
 215
 216   /* Copy constructor.  */
 217   ipa_call_summary (const ipa_call_summary &s):
 218     predicate (s.predicate), param (s.param), call_stmt_size (s.call_stmt_size),
 219     call_stmt_time (s.call_stmt_time), loop_depth (s.loop_depth),
 220     is_return_callee_uncaptured (s.is_return_callee_uncaptured)
 221   {
 222   }
 223
 224   /* Default destructor.  */
 225   ~ipa_call_summary ();
 226
 227   class predicate *predicate;
 228   /* Vector indexed by parameters.  */
 229   vec<inline_param_summary> param;
 230   /* Estimated size and time of the call statement.  */
 231   int call_stmt_size;
 232   int call_stmt_time;
 233   /* Depth of loop nest, 0 means no nesting.  */
 234   unsigned int loop_depth;
 235   /* Indicates whether the caller returns the value of it's callee.  */
 236   bool is_return_callee_uncaptured;
 237 };
 238
 239 class ipa_call_summary_t: public call_summary <ipa_call_summary *>
 240 {
 241 public:
 242   ipa_call_summary_t (symbol_table *symtab, bool ggc):
 243     call_summary <ipa_call_summary *> (symtab, ggc) {}
 244
 245   /* Hook that is called by summary when an edge is duplicated.  */
 246   virtual void duplicate (cgraph_edge *src, cgraph_edge *dst,
 247                           ipa_call_summary *src_data,
 248                           ipa_call_summary *dst_data);
 249 };
 250
 251 extern call_summary <ipa_call_summary *> *ipa_call_summaries;
 252
 253 /* In ipa-fnsummary.c  */
 254 void ipa_debug_fn_summary (struct cgraph_node *);
 255 void ipa_dump_fn_summaries (FILE *f);
 256 void ipa_dump_fn_summary (FILE *f, struct cgraph_node *node);
 257 void ipa_dump_hints (FILE *f, ipa_hints);
 258 void ipa_free_fn_summary (void);
 259 void inline_analyze_function (struct cgraph_node *node);
 260 void estimate_ipcp_clone_size_and_time (struct cgraph_node *,
 261                                         vec<tree>,
 262                                         vec<ipa_polymorphic_call_context>,
 263                                         vec<ipa_agg_jump_function_p>,
 264                                         int *, sreal *, sreal *,
 265                                         ipa_hints *);
 266 void ipa_merge_fn_summary_after_inlining (struct cgraph_edge *edge);
 267 void ipa_update_overall_fn_summary (struct cgraph_node *node);
 268 void compute_fn_summary (struct cgraph_node *, bool);
 269
 270
 271 void evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 272                                    clause_t *clause_ptr,
 273                                    clause_t *nonspec_clause_ptr,
 274                                    vec<tree> *known_vals_ptr,
 275                                    vec<ipa_polymorphic_call_context>
 276                                    *known_contexts_ptr,
 277                                    vec<ipa_agg_jump_function_p> *);
 278 void estimate_node_size_and_time (struct cgraph_node *node,
 279                                   clause_t possible_truths,
 280                                   clause_t nonspec_possible_truths,
 281                                   vec<tree> known_vals,
 282                                   vec<ipa_polymorphic_call_context>,
 283                                   vec<ipa_agg_jump_function_p> known_aggs,
 284                                   int *ret_size, int *ret_min_size,
 285                                   sreal *ret_time,
 286                                   sreal *ret_nonspecialized_time,
 287                                   ipa_hints *ret_hints,
 288                                   vec<inline_param_summary>
 289                                   inline_param_summary);
 290
 291 void ipa_fnsummary_c_finalize (void);
 292
 293 #endif /* GCC_IPA_FNSUMMARY_H */