gcc/ipa-fnsummary.h

   1 /* IPA function body analysis.
   2    Copyright (C) 2003-2019 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   /* We know that the callee is hot by profile.  */
  52   INLINE_HINT_known_hot = 128
  53 };
  54
  55 typedef int ipa_hints;
  56
  57 /* Simple description of whether a memory load or a condition refers to a load
  58    from an aggregate and if so, how and where from in the aggregate.
  59    Individual fields have the same meaning like fields with the same name in
  60    struct condition.  */
  61
  62 struct agg_position_info
  63 {
  64   HOST_WIDE_INT offset;
  65   bool agg_contents;
  66   bool by_ref;
  67 };
  68
  69 /* Representation of function body size and time depending on the call
  70    context.  We keep simple array of record, every containing of predicate
  71    and time/size to account.  */
  72 class GTY(()) size_time_entry
  73 {
  74 public:
  75   /* Predicate for code to be executed.  */
  76   predicate exec_predicate;
  77   /* Predicate for value to be constant and optimized out in a specialized copy.
  78      When deciding on specialization this makes it possible to see how much
  79      the executed code paths will simplify.  */
  80   predicate nonconst_predicate;
  81   int size;
  82   sreal GTY((skip)) time;
  83 };
  84
  85 /* Summary about function and stack frame sizes.  We keep this info
  86    for inline clones and also for WPA streaming. For this reason this is not
  87    part of ipa_fn_summary which exists only for offline functions.  */
  88 class ipa_size_summary
  89 {
  90 public:
  91   /* Estimated stack frame consumption by the function.  */
  92   HOST_WIDE_INT estimated_self_stack_size;
  93   /* Size of the function body.  */
  94   int self_size;
  95   /* Estimated size of the function after inlining.  */
  96   int size;
  97
  98   ipa_size_summary ()
  99   : estimated_self_stack_size (0), self_size (0), size (0)
 100   {
 101   }
 102   /* Copy constructor.  */
 103   ipa_size_summary (const ipa_size_summary &s)
 104   : estimated_self_stack_size (0), self_size (s.self_size), size (s.size)
 105   {
 106   }
 107 };
 108
 109 /* Function inlining information.  */
 110 class GTY(()) ipa_fn_summary
 111 {
 112 public:
 113   /* Keep all field empty so summary dumping works during its computation.
 114      This is useful for debugging.  */
 115   ipa_fn_summary ()
 116     : min_size (0),
 117       inlinable (false), single_caller (false),
 118       fp_expressions (false), estimated_stack_size (false),
 119       time (0), conds (NULL),
 120       size_time_table (NULL), loop_iterations (NULL), loop_stride (NULL),
 121       growth (0), scc_no (0)
 122   {
 123   }
 124
 125   /* Copy constructor.  */
 126   ipa_fn_summary (const ipa_fn_summary &s)
 127     : min_size (s.min_size),
 128     inlinable (s.inlinable), single_caller (s.single_caller),
 129     fp_expressions (s.fp_expressions),
 130     estimated_stack_size (s.estimated_stack_size),
 131     time (s.time), conds (s.conds), size_time_table (s.size_time_table),
 132     loop_iterations (s.loop_iterations), loop_stride (s.loop_stride),
 133     growth (s.growth), scc_no (s.scc_no)
 134   {}
 135
 136   /* Default constructor.  */
 137   ~ipa_fn_summary ();
 138
 139   /* Information about the function body itself.  */
 140
 141   /* Minimal size increase after inlining.  */
 142   int min_size;
 143
 144   /* False when there something makes inlining impossible (such as va_arg).  */
 145   unsigned inlinable : 1;
 146   /* True wen there is only one caller of the function before small function
 147      inlining.  */
 148   unsigned int single_caller : 1;
 149   /* True if function contains any floating point expressions.  */
 150   unsigned int fp_expressions : 1;
 151
 152   /* Information about function that will result after applying all the
 153      inline decisions present in the callgraph.  Generally kept up to
 154      date only for functions that are not inline clones. */
 155
 156   /* Estimated stack frame consumption by the function.  */
 157   HOST_WIDE_INT estimated_stack_size;
 158   /* Estimated runtime of function after inlining.  */
 159   sreal GTY((skip)) time;
 160
 161   /* Conditional size/time information.  The summaries are being
 162      merged during inlining.  */
 163   conditions conds;
 164   vec<size_time_entry, va_gc> *size_time_table;
 165
 166   /* Predicate on when some loop in the function becomes to have known
 167      bounds.   */
 168   predicate * GTY((skip)) loop_iterations;
 169   /* Predicate on when some loop in the function becomes to have known
 170      stride.   */
 171   predicate * GTY((skip)) loop_stride;
 172   /* Estimated growth for inlining all copies of the function before start
 173      of small functions inlining.
 174      This value will get out of date as the callers are duplicated, but
 175      using up-to-date value in the badness metric mean a lot of extra
 176      expenses.  */
 177   int growth;
 178   /* Number of SCC on the beginning of inlining process.  */
 179   int scc_no;
 180
 181   /* Record time and size under given predicates.  */
 182   void account_size_time (int, sreal, const predicate &, const predicate &);
 183
 184   /* We keep values scaled up, so fractional sizes can be accounted.  */
 185   static const int size_scale = 2;
 186 };
 187
 188 class GTY((user)) ipa_fn_summary_t:
 189   public fast_function_summary <ipa_fn_summary *, va_gc>
 190 {
 191 public:
 192   ipa_fn_summary_t (symbol_table *symtab):
 193     fast_function_summary <ipa_fn_summary *, va_gc> (symtab) {}
 194
 195   static ipa_fn_summary_t *create_ggc (symbol_table *symtab)
 196   {
 197     class ipa_fn_summary_t *summary
 198       = new (ggc_alloc_no_dtor<ipa_fn_summary_t> ()) ipa_fn_summary_t (symtab);
 199     summary->disable_insertion_hook ();
 200     return summary;
 201   }
 202
 203   /* Remove ipa_fn_summary for all callees of NODE.  */
 204   void remove_callees (cgraph_node *node);
 205
 206   virtual void insert (cgraph_node *, ipa_fn_summary *);
 207   virtual void remove (cgraph_node *node, ipa_fn_summary *)
 208   {
 209     remove_callees (node);
 210   }
 211
 212   virtual void duplicate (cgraph_node *src, cgraph_node *dst,
 213                           ipa_fn_summary *src_data, ipa_fn_summary *dst_data);
 214 };
 215
 216 extern GTY(()) fast_function_summary <ipa_fn_summary *, va_gc>
 217   *ipa_fn_summaries;
 218
 219 class ipa_size_summary_t:
 220   public fast_function_summary <ipa_size_summary *, va_gc>
 221 {
 222 public:
 223   ipa_size_summary_t (symbol_table *symtab):
 224     fast_function_summary <ipa_size_summary *, va_gc> (symtab) {}
 225
 226   static ipa_size_summary_t *create_ggc (symbol_table *symtab)
 227   {
 228     class ipa_size_summary_t *summary = new (ggc_alloc <ipa_size_summary_t> ())
 229       ipa_size_summary_t (symtab);
 230     summary->disable_insertion_hook ();
 231     return summary;
 232   }
 233 };
 234 extern fast_function_summary <ipa_size_summary *, va_heap>
 235   *ipa_size_summaries;
 236
 237 /* Information kept about callgraph edges.  */
 238 class ipa_call_summary
 239 {
 240 public:
 241   /* Keep all field empty so summary dumping works during its computation.
 242      This is useful for debugging.  */
 243   ipa_call_summary ()
 244     : predicate (NULL), param (vNULL), call_stmt_size (0), call_stmt_time (0),
 245       loop_depth (0), is_return_callee_uncaptured (false)
 246     {
 247     }
 248
 249   /* Copy constructor.  */
 250   ipa_call_summary (const ipa_call_summary &s):
 251     predicate (s.predicate), param (s.param), call_stmt_size (s.call_stmt_size),
 252     call_stmt_time (s.call_stmt_time), loop_depth (s.loop_depth),
 253     is_return_callee_uncaptured (s.is_return_callee_uncaptured)
 254   {
 255   }
 256
 257   /* Default destructor.  */
 258   ~ipa_call_summary ();
 259
 260   class predicate *predicate;
 261   /* Vector indexed by parameters.  */
 262   vec<inline_param_summary> param;
 263   /* Estimated size and time of the call statement.  */
 264   int call_stmt_size;
 265   int call_stmt_time;
 266   /* Depth of loop nest, 0 means no nesting.  */
 267   unsigned int loop_depth;
 268   /* Indicates whether the caller returns the value of it's callee.  */
 269   bool is_return_callee_uncaptured;
 270 };
 271
 272 class ipa_call_summary_t: public fast_call_summary <ipa_call_summary *, va_heap>
 273 {
 274 public:
 275   ipa_call_summary_t (symbol_table *symtab):
 276     fast_call_summary <ipa_call_summary *, va_heap> (symtab) {}
 277
 278   /* Hook that is called by summary when an edge is duplicated.  */
 279   virtual void duplicate (cgraph_edge *src, cgraph_edge *dst,
 280                           ipa_call_summary *src_data,
 281                           ipa_call_summary *dst_data);
 282 };
 283
 284 /* This object describe a context of call.  That is a summary of known
 285    information about its parameters.  Main purpose of this context is
 286    to give more realistic esitmations of function runtime, size and
 287    inline hints.  */
 288 class ipa_call_context
 289 {
 290 public:
 291   ipa_call_context (cgraph_node *node,
 292                     clause_t possible_truths,
 293                     clause_t nonspec_possible_truths,
 294                     vec<tree> known_vals,
 295                     vec<ipa_polymorphic_call_context> known_contexts,
 296                     vec<ipa_agg_jump_function_p> known_aggs,
 297                     vec<inline_param_summary> m_inline_param_summary);
 298   ipa_call_context ()
 299   : m_node(NULL)
 300   {
 301   }
 302   void estimate_size_and_time (int *ret_size, int *ret_min_size,
 303                                sreal *ret_time,
 304                                sreal *ret_nonspecialized_time,
 305                                ipa_hints *ret_hints);
 306   void duplicate_from (const ipa_call_context &ctx);
 307   void release (bool all = false);
 308   bool equal_to (const ipa_call_context &);
 309   bool exists_p ()
 310   {
 311     return m_node != NULL;
 312   }
 313 private:
 314   /* Called function.  */
 315   cgraph_node *m_node;
 316   /* Clause describing what predicate conditionals can be satisfied
 317      in this context if function is inlined/specialised.  */
 318   clause_t m_possible_truths;
 319   /* Clause describing what predicate conditionals can be satisfied
 320      in this context if function is kept offline.  */
 321   clause_t m_nonspec_possible_truths;
 322   /* Inline summary maintains info about change probabilities.  */
 323   vec<inline_param_summary> m_inline_param_summary;
 324
 325   /* The following is used only to resolve indirect calls.  */
 326
 327   /* Vector describing known values of parameters.  */
 328   vec<tree> m_known_vals;
 329   /* Vector describing known polymorphic call contexts.  */
 330   vec<ipa_polymorphic_call_context> m_known_contexts;
 331   /* Vector describing known aggregate values.  */
 332   vec<ipa_agg_jump_function_p> m_known_aggs;
 333 };
 334
 335 extern fast_call_summary <ipa_call_summary *, va_heap> *ipa_call_summaries;
 336
 337 /* In ipa-fnsummary.c  */
 338 void ipa_debug_fn_summary (struct cgraph_node *);
 339 void ipa_dump_fn_summaries (FILE *f);
 340 void ipa_dump_fn_summary (FILE *f, struct cgraph_node *node);
 341 void ipa_dump_hints (FILE *f, ipa_hints);
 342 void ipa_free_fn_summary (void);
 343 void ipa_free_size_summary (void);
 344 void inline_analyze_function (struct cgraph_node *node);
 345 void estimate_ipcp_clone_size_and_time (struct cgraph_node *,
 346                                         vec<tree>,
 347                                         vec<ipa_polymorphic_call_context>,
 348                                         vec<ipa_agg_jump_function_p>,
 349                                         int *, sreal *, sreal *,
 350                                         ipa_hints *);
 351 void ipa_merge_fn_summary_after_inlining (struct cgraph_edge *edge);
 352 void ipa_update_overall_fn_summary (struct cgraph_node *node);
 353 void compute_fn_summary (struct cgraph_node *, bool);
 354
 355
 356 void evaluate_properties_for_edge (struct cgraph_edge *e,
 357                                    bool inline_p,
 358                                    clause_t *clause_ptr,
 359                                    clause_t *nonspec_clause_ptr,
 360                                    vec<tree> *known_vals_ptr,
 361                                    vec<ipa_polymorphic_call_context>
 362                                    *known_contexts_ptr,
 363                                    vec<ipa_agg_jump_function_p> *);
 364
 365 void ipa_fnsummary_c_finalize (void);
 366 HOST_WIDE_INT ipa_get_stack_frame_offset (struct cgraph_node *node);
 367 void ipa_remove_from_growth_caches (struct cgraph_edge *edge);
 368
 369 #endif /* GCC_IPA_FNSUMMARY_H */