xref: /dragonfly/contrib/gcc-8.0/gcc/ipa-inline.c (revision 95059079af47f9a66a175f374f2da1a5020e3255)
1 /* Inlining decision heuristics.
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 /*  Inlining decision heuristics
22 
23     The implementation of inliner is organized as follows:
24 
25     inlining heuristics limits
26 
27       can_inline_edge_p allow to check that particular inlining is allowed
28       by the limits specified by user (allowed function growth, growth and so
29       on).
30 
31       Functions are inlined when it is obvious the result is profitable (such
32       as functions called once or when inlining reduce code size).
33       In addition to that we perform inlining of small functions and recursive
34       inlining.
35 
36     inlining heuristics
37 
38        The inliner itself is split into two passes:
39 
40        pass_early_inlining
41 
42            Simple local inlining pass inlining callees into current function.
43            This pass makes no use of whole unit analysis and thus it can do only
44            very simple decisions based on local properties.
45 
46            The strength of the pass is that it is run in topological order
47            (reverse postorder) on the callgraph. Functions are converted into SSA
48            form just before this pass and optimized subsequently. As a result, the
49            callees of the function seen by the early inliner was already optimized
50            and results of early inlining adds a lot of optimization opportunities
51            for the local optimization.
52 
53            The pass handle the obvious inlining decisions within the compilation
54            unit - inlining auto inline functions, inlining for size and
55            flattening.
56 
57            main strength of the pass is the ability to eliminate abstraction
58            penalty in C++ code (via combination of inlining and early
59            optimization) and thus improve quality of analysis done by real IPA
60            optimizers.
61 
62            Because of lack of whole unit knowledge, the pass can not really make
63            good code size/performance tradeoffs.  It however does very simple
64            speculative inlining allowing code size to grow by
65            EARLY_INLINING_INSNS when callee is leaf function.  In this case the
66            optimizations performed later are very likely to eliminate the cost.
67 
68        pass_ipa_inline
69 
70            This is the real inliner able to handle inlining with whole program
71            knowledge. It performs following steps:
72 
73            1) inlining of small functions.  This is implemented by greedy
74            algorithm ordering all inlinable cgraph edges by their badness and
75            inlining them in this order as long as inline limits allows doing so.
76 
77            This heuristics is not very good on inlining recursive calls. Recursive
78            calls can be inlined with results similar to loop unrolling. To do so,
79            special purpose recursive inliner is executed on function when
80            recursive edge is met as viable candidate.
81 
82            2) Unreachable functions are removed from callgraph.  Inlining leads
83            to devirtualization and other modification of callgraph so functions
84            may become unreachable during the process. Also functions declared as
85            extern inline or virtual functions are removed, since after inlining
86            we no longer need the offline bodies.
87 
88            3) Functions called once and not exported from the unit are inlined.
89            This should almost always lead to reduction of code size by eliminating
90            the need for offline copy of the function.  */
91 
92 #include "config.h"
93 #include "system.h"
94 #include "coretypes.h"
95 #include "backend.h"
96 #include "target.h"
97 #include "rtl.h"
98 #include "tree.h"
99 #include "gimple.h"
100 #include "alloc-pool.h"
101 #include "tree-pass.h"
102 #include "gimple-ssa.h"
103 #include "cgraph.h"
104 #include "lto-streamer.h"
105 #include "trans-mem.h"
106 #include "calls.h"
107 #include "tree-inline.h"
108 #include "params.h"
109 #include "profile.h"
110 #include "symbol-summary.h"
111 #include "tree-vrp.h"
112 #include "ipa-prop.h"
113 #include "ipa-fnsummary.h"
114 #include "ipa-inline.h"
115 #include "ipa-utils.h"
116 #include "sreal.h"
117 #include "auto-profile.h"
118 #include "builtins.h"
119 #include "fibonacci_heap.h"
120 #include "stringpool.h"
121 #include "attribs.h"
122 #include "asan.h"
123 
124 typedef fibonacci_heap <sreal, cgraph_edge> edge_heap_t;
125 typedef fibonacci_node <sreal, cgraph_edge> edge_heap_node_t;
126 
127 /* Statistics we collect about inlining algorithm.  */
128 static int overall_size;
129 static profile_count max_count;
130 static profile_count spec_rem;
131 
132 /* Return false when inlining edge E would lead to violating
133    limits on function unit growth or stack usage growth.
134 
135    The relative function body growth limit is present generally
136    to avoid problems with non-linear behavior of the compiler.
137    To allow inlining huge functions into tiny wrapper, the limit
138    is always based on the bigger of the two functions considered.
139 
140    For stack growth limits we always base the growth in stack usage
141    of the callers.  We want to prevent applications from segfaulting
142    on stack overflow when functions with huge stack frames gets
143    inlined. */
144 
145 static bool
caller_growth_limits(struct cgraph_edge * e)146 caller_growth_limits (struct cgraph_edge *e)
147 {
148   struct cgraph_node *to = e->caller;
149   struct cgraph_node *what = e->callee->ultimate_alias_target ();
150   int newsize;
151   int limit = 0;
152   HOST_WIDE_INT stack_size_limit = 0, inlined_stack;
153   ipa_fn_summary *info, *what_info, *outer_info = ipa_fn_summaries->get (to);
154 
155   /* Look for function e->caller is inlined to.  While doing
156      so work out the largest function body on the way.  As
157      described above, we want to base our function growth
158      limits based on that.  Not on the self size of the
159      outer function, not on the self size of inline code
160      we immediately inline to.  This is the most relaxed
161      interpretation of the rule "do not grow large functions
162      too much in order to prevent compiler from exploding".  */
163   while (true)
164     {
165       info = ipa_fn_summaries->get (to);
166       if (limit < info->self_size)
167           limit = info->self_size;
168       if (stack_size_limit < info->estimated_self_stack_size)
169           stack_size_limit = info->estimated_self_stack_size;
170       if (to->global.inlined_to)
171         to = to->callers->caller;
172       else
173           break;
174     }
175 
176   what_info = ipa_fn_summaries->get (what);
177 
178   if (limit < what_info->self_size)
179     limit = what_info->self_size;
180 
181   limit += limit * PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH) / 100;
182 
183   /* Check the size after inlining against the function limits.  But allow
184      the function to shrink if it went over the limits by forced inlining.  */
185   newsize = estimate_size_after_inlining (to, e);
186   if (newsize >= info->size
187       && newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS)
188       && newsize > limit)
189     {
190       e->inline_failed = CIF_LARGE_FUNCTION_GROWTH_LIMIT;
191       return false;
192     }
193 
194   if (!what_info->estimated_stack_size)
195     return true;
196 
197   /* FIXME: Stack size limit often prevents inlining in Fortran programs
198      due to large i/o datastructures used by the Fortran front-end.
199      We ought to ignore this limit when we know that the edge is executed
200      on every invocation of the caller (i.e. its call statement dominates
201      exit block).  We do not track this information, yet.  */
202   stack_size_limit += ((gcov_type)stack_size_limit
203                            * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100);
204 
205   inlined_stack = (outer_info->stack_frame_offset
206                        + outer_info->estimated_self_stack_size
207                        + what_info->estimated_stack_size);
208   /* Check new stack consumption with stack consumption at the place
209      stack is used.  */
210   if (inlined_stack > stack_size_limit
211       /* If function already has large stack usage from sibling
212            inline call, we can inline, too.
213            This bit overoptimistically assume that we are good at stack
214            packing.  */
215       && inlined_stack > info->estimated_stack_size
216       && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME))
217     {
218       e->inline_failed = CIF_LARGE_STACK_FRAME_GROWTH_LIMIT;
219       return false;
220     }
221   return true;
222 }
223 
224 /* Dump info about why inlining has failed.  */
225 
226 static void
report_inline_failed_reason(struct cgraph_edge * e)227 report_inline_failed_reason (struct cgraph_edge *e)
228 {
229   if (dump_file)
230     {
231       fprintf (dump_file, "  not inlinable: %s -> %s, %s\n",
232                  e->caller->dump_name (),
233                  e->callee->dump_name (),
234                  cgraph_inline_failed_string (e->inline_failed));
235       if ((e->inline_failed == CIF_TARGET_OPTION_MISMATCH
236              || e->inline_failed == CIF_OPTIMIZATION_MISMATCH)
237             && e->caller->lto_file_data
238             && e->callee->ultimate_alias_target ()->lto_file_data)
239           {
240             fprintf (dump_file, "  LTO objects: %s, %s\n",
241                        e->caller->lto_file_data->file_name,
242                        e->callee->ultimate_alias_target ()->lto_file_data->file_name);
243           }
244       if (e->inline_failed == CIF_TARGET_OPTION_MISMATCH)
245           cl_target_option_print_diff
246            (dump_file, 2, target_opts_for_fn (e->caller->decl),
247           target_opts_for_fn (e->callee->ultimate_alias_target ()->decl));
248       if (e->inline_failed == CIF_OPTIMIZATION_MISMATCH)
249           cl_optimization_print_diff
250             (dump_file, 2, opts_for_fn (e->caller->decl),
251              opts_for_fn (e->callee->ultimate_alias_target ()->decl));
252     }
253 }
254 
255  /* Decide whether sanitizer-related attributes allow inlining. */
256 
257 static bool
sanitize_attrs_match_for_inline_p(const_tree caller,const_tree callee)258 sanitize_attrs_match_for_inline_p (const_tree caller, const_tree callee)
259 {
260   if (!caller || !callee)
261     return true;
262 
263   /* Allow inlining always_inline functions into no_sanitize_address
264      functions.  */
265   if (!sanitize_flags_p (SANITIZE_ADDRESS, caller)
266       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (callee)))
267     return true;
268 
269   return ((sanitize_flags_p (SANITIZE_ADDRESS, caller)
270              == sanitize_flags_p (SANITIZE_ADDRESS, callee))
271             && (sanitize_flags_p (SANITIZE_POINTER_COMPARE, caller)
272                 == sanitize_flags_p (SANITIZE_POINTER_COMPARE, callee))
273             && (sanitize_flags_p (SANITIZE_POINTER_SUBTRACT, caller)
274                 == sanitize_flags_p (SANITIZE_POINTER_SUBTRACT, callee)));
275 }
276 
277 /* Used for flags where it is safe to inline when caller's value is
278    grater than callee's.  */
279 #define check_maybe_up(flag) \
280       (opts_for_fn (caller->decl)->x_##flag                 \
281        != opts_for_fn (callee->decl)->x_##flag              \
282        && (!always_inline                                   \
283              || opts_for_fn (caller->decl)->x_##flag        \
284                 < opts_for_fn (callee->decl)->x_##flag))
285 /* Used for flags where it is safe to inline when caller's value is
286    smaller than callee's.  */
287 #define check_maybe_down(flag) \
288       (opts_for_fn (caller->decl)->x_##flag                 \
289        != opts_for_fn (callee->decl)->x_##flag              \
290        && (!always_inline                                   \
291              || opts_for_fn (caller->decl)->x_##flag        \
292                 > opts_for_fn (callee->decl)->x_##flag))
293 /* Used for flags where exact match is needed for correctness.  */
294 #define check_match(flag) \
295       (opts_for_fn (caller->decl)->x_##flag                 \
296        != opts_for_fn (callee->decl)->x_##flag)
297 
298 /* Decide if we can inline the edge and possibly update
299    inline_failed reason.
300    We check whether inlining is possible at all and whether
301    caller growth limits allow doing so.
302 
303    if REPORT is true, output reason to the dump file. */
304 
305 static bool
306 can_inline_edge_p (struct cgraph_edge *e, bool report,
307                        bool early = false)
308 {
309   gcc_checking_assert (e->inline_failed);
310 
311   if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
312     {
313       if (report)
314         report_inline_failed_reason (e);
315       return false;
316     }
317 
318   bool inlinable = true;
319   enum availability avail;
320   cgraph_node *caller = e->caller->global.inlined_to
321                             ? e->caller->global.inlined_to : e->caller;
322   cgraph_node *callee = e->callee->ultimate_alias_target (&avail, caller);
323 
324   if (!callee->definition)
325     {
326       e->inline_failed = CIF_BODY_NOT_AVAILABLE;
327       inlinable = false;
328     }
329   if (!early && (!opt_for_fn (callee->decl, optimize)
330                      || !opt_for_fn (caller->decl, optimize)))
331     {
332       e->inline_failed = CIF_FUNCTION_NOT_OPTIMIZED;
333       inlinable = false;
334     }
335   else if (callee->calls_comdat_local)
336     {
337       e->inline_failed = CIF_USES_COMDAT_LOCAL;
338       inlinable = false;
339     }
340   else if (avail <= AVAIL_INTERPOSABLE)
341     {
342       e->inline_failed = CIF_OVERWRITABLE;
343       inlinable = false;
344     }
345   /* All edges with call_stmt_cannot_inline_p should have inline_failed
346      initialized to one of FINAL_ERROR reasons.  */
347   else if (e->call_stmt_cannot_inline_p)
348     gcc_unreachable ();
349   /* Don't inline if the functions have different EH personalities.  */
350   else if (DECL_FUNCTION_PERSONALITY (caller->decl)
351              && DECL_FUNCTION_PERSONALITY (callee->decl)
352              && (DECL_FUNCTION_PERSONALITY (caller->decl)
353                  != DECL_FUNCTION_PERSONALITY (callee->decl)))
354     {
355       e->inline_failed = CIF_EH_PERSONALITY;
356       inlinable = false;
357     }
358   /* TM pure functions should not be inlined into non-TM_pure
359      functions.  */
360   else if (is_tm_pure (callee->decl) && !is_tm_pure (caller->decl))
361     {
362       e->inline_failed = CIF_UNSPECIFIED;
363       inlinable = false;
364     }
365   /* Check compatibility of target optimization options.  */
366   else if (!targetm.target_option.can_inline_p (caller->decl,
367                                                             callee->decl))
368     {
369       e->inline_failed = CIF_TARGET_OPTION_MISMATCH;
370       inlinable = false;
371     }
372   else if (!ipa_fn_summaries->get (callee)->inlinable)
373     {
374       e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
375       inlinable = false;
376     }
377   /* Don't inline a function with mismatched sanitization attributes. */
378   else if (!sanitize_attrs_match_for_inline_p (caller->decl, callee->decl))
379     {
380       e->inline_failed = CIF_ATTRIBUTE_MISMATCH;
381       inlinable = false;
382     }
383   if (!inlinable && report)
384     report_inline_failed_reason (e);
385   return inlinable;
386 }
387 
388 /* Decide if we can inline the edge and possibly update
389    inline_failed reason.
390    We check whether inlining is possible at all and whether
391    caller growth limits allow doing so.
392 
393    if REPORT is true, output reason to the dump file.
394 
395    if DISREGARD_LIMITS is true, ignore size limits.  */
396 
397 static bool
398 can_inline_edge_by_limits_p (struct cgraph_edge *e, bool report,
399                                  bool disregard_limits = false, bool early = false)
400 {
401   gcc_checking_assert (e->inline_failed);
402 
403   if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
404     {
405       if (report)
406         report_inline_failed_reason (e);
407       return false;
408     }
409 
410   bool inlinable = true;
411   enum availability avail;
412   cgraph_node *caller = e->caller->global.inlined_to
413                             ? e->caller->global.inlined_to : e->caller;
414   cgraph_node *callee = e->callee->ultimate_alias_target (&avail, caller);
415   tree caller_tree = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (caller->decl);
416   tree callee_tree
417     = callee ? DECL_FUNCTION_SPECIFIC_OPTIMIZATION (callee->decl) : NULL;
418   /* Check if caller growth allows the inlining.  */
419   if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl)
420       && !disregard_limits
421       && !lookup_attribute ("flatten",
422                      DECL_ATTRIBUTES (caller->decl))
423       && !caller_growth_limits (e))
424     inlinable = false;
425   /* Don't inline a function with a higher optimization level than the
426      caller.  FIXME: this is really just tip of iceberg of handling
427      optimization attribute.  */
428   else if (caller_tree != callee_tree)
429     {
430       bool always_inline =
431                (DECL_DISREGARD_INLINE_LIMITS (callee->decl)
432                 && lookup_attribute ("always_inline",
433                                            DECL_ATTRIBUTES (callee->decl)));
434       ipa_fn_summary *caller_info = ipa_fn_summaries->get (caller);
435       ipa_fn_summary *callee_info = ipa_fn_summaries->get (callee);
436 
437      /* Until GCC 4.9 we did not check the semantics alterning flags
438           bellow and inline across optimization boundry.
439           Enabling checks bellow breaks several packages by refusing
440           to inline library always_inline functions. See PR65873.
441           Disable the check for early inlining for now until better solution
442           is found.  */
443      if (always_inline && early)
444           ;
445       /* There are some options that change IL semantics which means
446          we cannot inline in these cases for correctness reason.
447            Not even for always_inline declared functions.  */
448      else if (check_match (flag_wrapv)
449                 || check_match (flag_trapv)
450                 || check_match (flag_pcc_struct_return)
451                 /* When caller or callee does FP math, be sure FP codegen flags
452                      compatible.  */
453                 || ((caller_info->fp_expressions && callee_info->fp_expressions)
454                       && (check_maybe_up (flag_rounding_math)
455                           || check_maybe_up (flag_trapping_math)
456                           || check_maybe_down (flag_unsafe_math_optimizations)
457                           || check_maybe_down (flag_finite_math_only)
458                           || check_maybe_up (flag_signaling_nans)
459                           || check_maybe_down (flag_cx_limited_range)
460                           || check_maybe_up (flag_signed_zeros)
461                           || check_maybe_down (flag_associative_math)
462                           || check_maybe_down (flag_reciprocal_math)
463                           || check_maybe_down (flag_fp_int_builtin_inexact)
464                           /* Strictly speaking only when the callee contains function
465                                calls that may end up setting errno.  */
466                           || check_maybe_up (flag_errno_math)))
467                 /* We do not want to make code compiled with exceptions to be
468                      brought into a non-EH function unless we know that the callee
469                      does not throw.
470                      This is tracked by DECL_FUNCTION_PERSONALITY.  */
471                 || (check_maybe_up (flag_non_call_exceptions)
472                       && DECL_FUNCTION_PERSONALITY (callee->decl))
473                 || (check_maybe_up (flag_exceptions)
474                       && DECL_FUNCTION_PERSONALITY (callee->decl))
475                 /* When devirtualization is diabled for callee, it is not safe
476                      to inline it as we possibly mangled the type info.
477                      Allow early inlining of always inlines.  */
478                 || (!early && check_maybe_down (flag_devirtualize)))
479           {
480             e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
481             inlinable = false;
482           }
483       /* gcc.dg/pr43564.c.  Apply user-forced inline even at -O0.  */
484       else if (always_inline)
485           ;
486       /* When user added an attribute to the callee honor it.  */
487       else if (lookup_attribute ("optimize", DECL_ATTRIBUTES (callee->decl))
488                  && opts_for_fn (caller->decl) != opts_for_fn (callee->decl))
489           {
490             e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
491             inlinable = false;
492           }
493       /* If explicit optimize attribute are not used, the mismatch is caused
494            by different command line options used to build different units.
495            Do not care about COMDAT functions - those are intended to be
496          optimized with the optimization flags of module they are used in.
497            Also do not care about mixing up size/speed optimization when
498            DECL_DISREGARD_INLINE_LIMITS is set.  */
499       else if ((callee->merged_comdat
500                   && !lookup_attribute ("optimize",
501                                               DECL_ATTRIBUTES (caller->decl)))
502                  || DECL_DISREGARD_INLINE_LIMITS (callee->decl))
503           ;
504       /* If mismatch is caused by merging two LTO units with different
505            optimizationflags we want to be bit nicer.  However never inline
506            if one of functions is not optimized at all.  */
507       else if (!opt_for_fn (callee->decl, optimize)
508                  || !opt_for_fn (caller->decl, optimize))
509           {
510             e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
511             inlinable = false;
512           }
513       /* If callee is optimized for size and caller is not, allow inlining if
514            code shrinks or we are in MAX_INLINE_INSNS_SINGLE limit and callee
515            is inline (and thus likely an unified comdat).  This will allow caller
516            to run faster.  */
517       else if (opt_for_fn (callee->decl, optimize_size)
518                  > opt_for_fn (caller->decl, optimize_size))
519           {
520             int growth = estimate_edge_growth (e);
521             if (growth > 0
522                 && (!DECL_DECLARED_INLINE_P (callee->decl)
523                       && growth >= MAX (MAX_INLINE_INSNS_SINGLE,
524                                             MAX_INLINE_INSNS_AUTO)))
525               {
526                 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
527                 inlinable = false;
528               }
529           }
530       /* If callee is more aggressively optimized for performance than caller,
531            we generally want to inline only cheap (runtime wise) functions.  */
532       else if (opt_for_fn (callee->decl, optimize_size)
533                  < opt_for_fn (caller->decl, optimize_size)
534                  || (opt_for_fn (callee->decl, optimize)
535                        > opt_for_fn (caller->decl, optimize)))
536           {
537             if (estimate_edge_time (e)
538                 >= 20 + ipa_call_summaries->get (e)->call_stmt_time)
539               {
540                 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
541                 inlinable = false;
542               }
543           }
544 
545     }
546 
547   if (!inlinable && report)
548     report_inline_failed_reason (e);
549   return inlinable;
550 }
551 
552 
553 /* Return true if the edge E is inlinable during early inlining.  */
554 
555 static bool
can_early_inline_edge_p(struct cgraph_edge * e)556 can_early_inline_edge_p (struct cgraph_edge *e)
557 {
558   struct cgraph_node *callee = e->callee->ultimate_alias_target ();
559   /* Early inliner might get called at WPA stage when IPA pass adds new
560      function.  In this case we can not really do any of early inlining
561      because function bodies are missing.  */
562   if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
563     return false;
564   if (!gimple_has_body_p (callee->decl))
565     {
566       e->inline_failed = CIF_BODY_NOT_AVAILABLE;
567       return false;
568     }
569   /* In early inliner some of callees may not be in SSA form yet
570      (i.e. the callgraph is cyclic and we did not process
571      the callee by early inliner, yet).  We don't have CIF code for this
572      case; later we will re-do the decision in the real inliner.  */
573   if (!gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->caller->decl))
574       || !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
575     {
576       if (dump_file)
577           fprintf (dump_file, "  edge not inlinable: not in SSA form\n");
578       return false;
579     }
580   if (!can_inline_edge_p (e, true, true)
581       || !can_inline_edge_by_limits_p (e, true, false, true))
582     return false;
583   return true;
584 }
585 
586 
587 /* Return number of calls in N.  Ignore cheap builtins.  */
588 
589 static int
num_calls(struct cgraph_node * n)590 num_calls (struct cgraph_node *n)
591 {
592   struct cgraph_edge *e;
593   int num = 0;
594 
595   for (e = n->callees; e; e = e->next_callee)
596     if (!is_inexpensive_builtin (e->callee->decl))
597       num++;
598   return num;
599 }
600 
601 
602 /* Return true if we are interested in inlining small function.  */
603 
604 static bool
want_early_inline_function_p(struct cgraph_edge * e)605 want_early_inline_function_p (struct cgraph_edge *e)
606 {
607   bool want_inline = true;
608   struct cgraph_node *callee = e->callee->ultimate_alias_target ();
609 
610   if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
611     ;
612   /* For AutoFDO, we need to make sure that before profile summary, all
613      hot paths' IR look exactly the same as profiled binary. As a result,
614      in einliner, we will disregard size limit and inline those callsites
615      that are:
616        * inlined in the profiled binary, and
617        * the cloned callee has enough samples to be considered "hot".  */
618   else if (flag_auto_profile && afdo_callsite_hot_enough_for_early_inline (e))
619     ;
620   else if (!DECL_DECLARED_INLINE_P (callee->decl)
621              && !opt_for_fn (e->caller->decl, flag_inline_small_functions))
622     {
623       e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
624       report_inline_failed_reason (e);
625       want_inline = false;
626     }
627   else
628     {
629       int growth = estimate_edge_growth (e);
630       int n;
631 
632       if (growth <= 0)
633           ;
634       else if (!e->maybe_hot_p ()
635                  && growth > 0)
636           {
637             if (dump_file)
638               fprintf (dump_file, "  will not early inline: %s->%s, "
639                          "call is cold and code would grow by %i\n",
640                          e->caller->dump_name (),
641                          callee->dump_name (),
642                          growth);
643             want_inline = false;
644           }
645       else if (growth > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
646           {
647             if (dump_file)
648               fprintf (dump_file, "  will not early inline: %s->%s, "
649                          "growth %i exceeds --param early-inlining-insns\n",
650                          e->caller->dump_name (),
651                          callee->dump_name (),
652                          growth);
653             want_inline = false;
654           }
655       else if ((n = num_calls (callee)) != 0
656                  && growth * (n + 1) > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
657           {
658             if (dump_file)
659               fprintf (dump_file, "  will not early inline: %s->%s, "
660                          "growth %i exceeds --param early-inlining-insns "
661                          "divided by number of calls\n",
662                          e->caller->dump_name (),
663                          callee->dump_name (),
664                          growth);
665             want_inline = false;
666           }
667     }
668   return want_inline;
669 }
670 
671 /* Compute time of the edge->caller + edge->callee execution when inlining
672    does not happen.  */
673 
674 inline sreal
compute_uninlined_call_time(struct cgraph_edge * edge,sreal uninlined_call_time)675 compute_uninlined_call_time (struct cgraph_edge *edge,
676                                    sreal uninlined_call_time)
677 {
678   cgraph_node *caller = (edge->caller->global.inlined_to
679                                ? edge->caller->global.inlined_to
680                                : edge->caller);
681 
682   sreal freq = edge->sreal_frequency ();
683   if (freq > 0)
684     uninlined_call_time *= freq;
685   else
686     uninlined_call_time = uninlined_call_time >> 11;
687 
688   sreal caller_time = ipa_fn_summaries->get (caller)->time;
689   return uninlined_call_time + caller_time;
690 }
691 
692 /* Same as compute_uinlined_call_time but compute time when inlining
693    does happen.  */
694 
695 inline sreal
compute_inlined_call_time(struct cgraph_edge * edge,sreal time)696 compute_inlined_call_time (struct cgraph_edge *edge,
697                                  sreal time)
698 {
699   cgraph_node *caller = (edge->caller->global.inlined_to
700                                ? edge->caller->global.inlined_to
701                                : edge->caller);
702   sreal caller_time = ipa_fn_summaries->get (caller)->time;
703 
704   sreal freq = edge->sreal_frequency ();
705   if (freq > 0)
706     time *= freq;
707   else
708     time = time >> 11;
709 
710   /* This calculation should match one in ipa-inline-analysis.c
711      (estimate_edge_size_and_time).  */
712   time -= (sreal)ipa_call_summaries->get (edge)->call_stmt_time * freq;
713   time += caller_time;
714   if (time <= 0)
715     time = ((sreal) 1) >> 8;
716   gcc_checking_assert (time >= 0);
717   return time;
718 }
719 
720 /* Return true if the speedup for inlining E is bigger than
721    PARAM_MAX_INLINE_MIN_SPEEDUP.  */
722 
723 static bool
big_speedup_p(struct cgraph_edge * e)724 big_speedup_p (struct cgraph_edge *e)
725 {
726   sreal unspec_time;
727   sreal spec_time = estimate_edge_time (e, &unspec_time);
728   sreal time = compute_uninlined_call_time (e, unspec_time);
729   sreal inlined_time = compute_inlined_call_time (e, spec_time);
730 
731   if ((time - inlined_time) * 100
732       > (sreal) (time * PARAM_VALUE (PARAM_INLINE_MIN_SPEEDUP)))
733     return true;
734   return false;
735 }
736 
737 /* Return true if we are interested in inlining small function.
738    When REPORT is true, report reason to dump file.  */
739 
740 static bool
want_inline_small_function_p(struct cgraph_edge * e,bool report)741 want_inline_small_function_p (struct cgraph_edge *e, bool report)
742 {
743   bool want_inline = true;
744   struct cgraph_node *callee = e->callee->ultimate_alias_target ();
745 
746   /* Allow this function to be called before can_inline_edge_p,
747      since it's usually cheaper.  */
748   if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
749     want_inline = false;
750   else if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
751     ;
752   else if (!DECL_DECLARED_INLINE_P (callee->decl)
753              && !opt_for_fn (e->caller->decl, flag_inline_small_functions))
754     {
755       e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
756       want_inline = false;
757     }
758   /* Do fast and conservative check if the function can be good
759      inline candidate.  At the moment we allow inline hints to
760      promote non-inline functions to inline and we increase
761      MAX_INLINE_INSNS_SINGLE 16-fold for inline functions.  */
762   else if ((!DECL_DECLARED_INLINE_P (callee->decl)
763              && (!e->count.ipa ().initialized_p () || !e->maybe_hot_p ()))
764              && ipa_fn_summaries->get (callee)->min_size
765                     - ipa_call_summaries->get (e)->call_stmt_size
766                 > MAX (MAX_INLINE_INSNS_SINGLE, MAX_INLINE_INSNS_AUTO))
767     {
768       e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
769       want_inline = false;
770     }
771   else if ((DECL_DECLARED_INLINE_P (callee->decl)
772               || e->count.ipa ().nonzero_p ())
773              && ipa_fn_summaries->get (callee)->min_size
774                     - ipa_call_summaries->get (e)->call_stmt_size
775                 > 16 * MAX_INLINE_INSNS_SINGLE)
776     {
777       e->inline_failed = (DECL_DECLARED_INLINE_P (callee->decl)
778                                 ? CIF_MAX_INLINE_INSNS_SINGLE_LIMIT
779                                 : CIF_MAX_INLINE_INSNS_AUTO_LIMIT);
780       want_inline = false;
781     }
782   else
783     {
784       int growth = estimate_edge_growth (e);
785       ipa_hints hints = estimate_edge_hints (e);
786       bool big_speedup = big_speedup_p (e);
787 
788       if (growth <= 0)
789           ;
790       /* Apply MAX_INLINE_INSNS_SINGLE limit.  Do not do so when
791            hints suggests that inlining given function is very profitable.  */
792       else if (DECL_DECLARED_INLINE_P (callee->decl)
793                  && growth >= MAX_INLINE_INSNS_SINGLE
794                  && ((!big_speedup
795                         && !(hints & (INLINE_HINT_indirect_call
796                                           | INLINE_HINT_known_hot
797                                           | INLINE_HINT_loop_iterations
798                                           | INLINE_HINT_array_index
799                                           | INLINE_HINT_loop_stride)))
800                        || growth >= MAX_INLINE_INSNS_SINGLE * 16))
801           {
802           e->inline_failed = CIF_MAX_INLINE_INSNS_SINGLE_LIMIT;
803             want_inline = false;
804           }
805       else if (!DECL_DECLARED_INLINE_P (callee->decl)
806                  && !opt_for_fn (e->caller->decl, flag_inline_functions))
807           {
808             /* growth_likely_positive is expensive, always test it last.  */
809           if (growth >= MAX_INLINE_INSNS_SINGLE
810                 || growth_likely_positive (callee, growth))
811               {
812               e->inline_failed = CIF_NOT_DECLARED_INLINED;
813                 want_inline = false;
814               }
815           }
816       /* Apply MAX_INLINE_INSNS_AUTO limit for functions not declared inline
817            Upgrade it to MAX_INLINE_INSNS_SINGLE when hints suggests that
818            inlining given function is very profitable.  */
819       else if (!DECL_DECLARED_INLINE_P (callee->decl)
820                  && !big_speedup
821                  && !(hints & INLINE_HINT_known_hot)
822                  && growth >= ((hints & (INLINE_HINT_indirect_call
823                                                | INLINE_HINT_loop_iterations
824                                              | INLINE_HINT_array_index
825                                                | INLINE_HINT_loop_stride))
826                                    ? MAX (MAX_INLINE_INSNS_AUTO,
827                                             MAX_INLINE_INSNS_SINGLE)
828                                    : MAX_INLINE_INSNS_AUTO))
829           {
830             /* growth_likely_positive is expensive, always test it last.  */
831           if (growth >= MAX_INLINE_INSNS_SINGLE
832                 || growth_likely_positive (callee, growth))
833               {
834                 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
835                 want_inline = false;
836               }
837           }
838       /* If call is cold, do not inline when function body would grow. */
839       else if (!e->maybe_hot_p ()
840                  && (growth >= MAX_INLINE_INSNS_SINGLE
841                        || growth_likely_positive (callee, growth)))
842           {
843           e->inline_failed = CIF_UNLIKELY_CALL;
844             want_inline = false;
845           }
846     }
847   if (!want_inline && report)
848     report_inline_failed_reason (e);
849   return want_inline;
850 }
851 
852 /* EDGE is self recursive edge.
853    We hand two cases - when function A is inlining into itself
854    or when function A is being inlined into another inliner copy of function
855    A within function B.
856 
857    In first case OUTER_NODE points to the toplevel copy of A, while
858    in the second case OUTER_NODE points to the outermost copy of A in B.
859 
860    In both cases we want to be extra selective since
861    inlining the call will just introduce new recursive calls to appear.  */
862 
863 static bool
want_inline_self_recursive_call_p(struct cgraph_edge * edge,struct cgraph_node * outer_node,bool peeling,int depth)864 want_inline_self_recursive_call_p (struct cgraph_edge *edge,
865                                            struct cgraph_node *outer_node,
866                                            bool peeling,
867                                            int depth)
868 {
869   char const *reason = NULL;
870   bool want_inline = true;
871   sreal caller_freq = 1;
872   int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO);
873 
874   if (DECL_DECLARED_INLINE_P (edge->caller->decl))
875     max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH);
876 
877   if (!edge->maybe_hot_p ())
878     {
879       reason = "recursive call is cold";
880       want_inline = false;
881     }
882   else if (depth > max_depth)
883     {
884       reason = "--param max-inline-recursive-depth exceeded.";
885       want_inline = false;
886     }
887   else if (outer_node->global.inlined_to
888              && (caller_freq = outer_node->callers->sreal_frequency ()) == 0)
889     {
890       reason = "caller frequency is 0";
891       want_inline = false;
892     }
893 
894   if (!want_inline)
895     ;
896   /* Inlining of self recursive function into copy of itself within other
897      function is transformation similar to loop peeling.
898 
899      Peeling is profitable if we can inline enough copies to make probability
900      of actual call to the self recursive function very small.  Be sure that
901      the probability of recursion is small.
902 
903      We ensure that the frequency of recursing is at most 1 - (1/max_depth).
904      This way the expected number of recursion is at most max_depth.  */
905   else if (peeling)
906     {
907       sreal max_prob = (sreal)1 - ((sreal)1 / (sreal)max_depth);
908       int i;
909       for (i = 1; i < depth; i++)
910           max_prob = max_prob * max_prob;
911       if (edge->sreal_frequency () >= max_prob * caller_freq)
912           {
913             reason = "frequency of recursive call is too large";
914             want_inline = false;
915           }
916     }
917   /* Recursive inlining, i.e. equivalent of unrolling, is profitable if
918      recursion depth is large.  We reduce function call overhead and increase
919      chances that things fit in hardware return predictor.
920 
921      Recursive inlining might however increase cost of stack frame setup
922      actually slowing down functions whose recursion tree is wide rather than
923      deep.
924 
925      Deciding reliably on when to do recursive inlining without profile feedback
926      is tricky.  For now we disable recursive inlining when probability of self
927      recursion is low.
928 
929      Recursive inlining of self recursive call within loop also results in
930      large loop depths that generally optimize badly.  We may want to throttle
931      down inlining in those cases.  In particular this seems to happen in one
932      of libstdc++ rb tree methods.  */
933   else
934     {
935       if (edge->sreal_frequency () * 100
936           <= caller_freq
937                * PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY))
938           {
939             reason = "frequency of recursive call is too small";
940             want_inline = false;
941           }
942     }
943   if (!want_inline && dump_file)
944     fprintf (dump_file, "   not inlining recursively: %s\n", reason);
945   return want_inline;
946 }
947 
948 /* Return true when NODE has uninlinable caller;
949    set HAS_HOT_CALL if it has hot call.
950    Worker for cgraph_for_node_and_aliases.  */
951 
952 static bool
check_callers(struct cgraph_node * node,void * has_hot_call)953 check_callers (struct cgraph_node *node, void *has_hot_call)
954 {
955   struct cgraph_edge *e;
956    for (e = node->callers; e; e = e->next_caller)
957      {
958        if (!opt_for_fn (e->caller->decl, flag_inline_functions_called_once)
959              || !opt_for_fn (e->caller->decl, optimize))
960            return true;
961        if (!can_inline_edge_p (e, true))
962          return true;
963        if (e->recursive_p ())
964            return true;
965        if (!can_inline_edge_by_limits_p (e, true))
966          return true;
967        if (!(*(bool *)has_hot_call) && e->maybe_hot_p ())
968            *(bool *)has_hot_call = true;
969      }
970   return false;
971 }
972 
973 /* If NODE has a caller, return true.  */
974 
975 static bool
has_caller_p(struct cgraph_node * node,void * data ATTRIBUTE_UNUSED)976 has_caller_p (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
977 {
978   if (node->callers)
979     return true;
980   return false;
981 }
982 
983 /* Decide if inlining NODE would reduce unit size by eliminating
984    the offline copy of function.
985    When COLD is true the cold calls are considered, too.  */
986 
987 static bool
want_inline_function_to_all_callers_p(struct cgraph_node * node,bool cold)988 want_inline_function_to_all_callers_p (struct cgraph_node *node, bool cold)
989 {
990   bool has_hot_call = false;
991 
992   /* Aliases gets inlined along with the function they alias.  */
993   if (node->alias)
994     return false;
995   /* Already inlined?  */
996   if (node->global.inlined_to)
997     return false;
998   /* Does it have callers?  */
999   if (!node->call_for_symbol_and_aliases (has_caller_p, NULL, true))
1000     return false;
1001   /* Inlining into all callers would increase size?  */
1002   if (estimate_growth (node) > 0)
1003     return false;
1004   /* All inlines must be possible.  */
1005   if (node->call_for_symbol_and_aliases (check_callers, &has_hot_call,
1006                                                    true))
1007     return false;
1008   if (!cold && !has_hot_call)
1009     return false;
1010   return true;
1011 }
1012 
1013 /* A cost model driving the inlining heuristics in a way so the edges with
1014    smallest badness are inlined first.  After each inlining is performed
1015    the costs of all caller edges of nodes affected are recomputed so the
1016    metrics may accurately depend on values such as number of inlinable callers
1017    of the function or function body size.  */
1018 
1019 static sreal
edge_badness(struct cgraph_edge * edge,bool dump)1020 edge_badness (struct cgraph_edge *edge, bool dump)
1021 {
1022   sreal badness;
1023   int growth;
1024   sreal edge_time, unspec_edge_time;
1025   struct cgraph_node *callee = edge->callee->ultimate_alias_target ();
1026   struct ipa_fn_summary *callee_info = ipa_fn_summaries->get (callee);
1027   ipa_hints hints;
1028   cgraph_node *caller = (edge->caller->global.inlined_to
1029                                ? edge->caller->global.inlined_to
1030                                : edge->caller);
1031 
1032   growth = estimate_edge_growth (edge);
1033   edge_time = estimate_edge_time (edge, &unspec_edge_time);
1034   hints = estimate_edge_hints (edge);
1035   gcc_checking_assert (edge_time >= 0);
1036   /* Check that inlined time is better, but tolerate some roundoff issues.
1037      FIXME: When callee profile drops to 0 we account calls more.  This
1038      should be fixed by never doing that.  */
1039   gcc_checking_assert ((edge_time * 100
1040                               - callee_info->time * 101).to_int () <= 0
1041                               || callee->count.ipa ().initialized_p ());
1042   gcc_checking_assert (growth <= callee_info->size);
1043 
1044   if (dump)
1045     {
1046       fprintf (dump_file, "    Badness calculation for %s -> %s\n",
1047                  edge->caller->dump_name (),
1048                  edge->callee->dump_name ());
1049       fprintf (dump_file, "      size growth %i, time %f unspec %f ",
1050                  growth,
1051                  edge_time.to_double (),
1052                  unspec_edge_time.to_double ());
1053       ipa_dump_hints (dump_file, hints);
1054       if (big_speedup_p (edge))
1055           fprintf (dump_file, " big_speedup");
1056       fprintf (dump_file, "\n");
1057     }
1058 
1059   /* Always prefer inlining saving code size.  */
1060   if (growth <= 0)
1061     {
1062       badness = (sreal) (-SREAL_MIN_SIG + growth) << (SREAL_MAX_EXP / 256);
1063       if (dump)
1064           fprintf (dump_file, "      %f: Growth %d <= 0\n", badness.to_double (),
1065                      growth);
1066     }
1067    /* Inlining into EXTERNAL functions is not going to change anything unless
1068       they are themselves inlined.  */
1069    else if (DECL_EXTERNAL (caller->decl))
1070     {
1071       if (dump)
1072           fprintf (dump_file, "      max: function is external\n");
1073       return sreal::max ();
1074     }
1075   /* When profile is available. Compute badness as:
1076 
1077                  time_saved * caller_count
1078      goodness =  -------------------------------------------------
1079                    growth_of_caller * overall_growth * combined_size
1080 
1081      badness = - goodness
1082 
1083      Again use negative value to make calls with profile appear hotter
1084      then calls without.
1085   */
1086   else if (opt_for_fn (caller->decl, flag_guess_branch_prob)
1087              || caller->count.ipa ().nonzero_p ())
1088     {
1089       sreal numerator, denominator;
1090       int overall_growth;
1091       sreal inlined_time = compute_inlined_call_time (edge, edge_time);
1092 
1093       numerator = (compute_uninlined_call_time (edge, unspec_edge_time)
1094                        - inlined_time);
1095       if (numerator <= 0)
1096           numerator = ((sreal) 1 >> 8);
1097       if (caller->count.ipa ().nonzero_p ())
1098           numerator *= caller->count.ipa ().to_gcov_type ();
1099       else if (caller->count.ipa ().initialized_p ())
1100           numerator = numerator >> 11;
1101       denominator = growth;
1102 
1103       overall_growth = callee_info->growth;
1104 
1105       /* Look for inliner wrappers of the form:
1106 
1107            inline_caller ()
1108              {
1109                do_fast_job...
1110                if (need_more_work)
1111                  noninline_callee ();
1112              }
1113            Withhout panilizing this case, we usually inline noninline_callee
1114            into the inline_caller because overall_growth is small preventing
1115            further inlining of inline_caller.
1116 
1117            Penalize only callgraph edges to functions with small overall
1118            growth ...
1119           */
1120       if (growth > overall_growth
1121             /* ... and having only one caller which is not inlined ... */
1122             && callee_info->single_caller
1123             && !edge->caller->global.inlined_to
1124             /* ... and edges executed only conditionally ... */
1125             && edge->sreal_frequency () < 1
1126             /* ... consider case where callee is not inline but caller is ... */
1127             && ((!DECL_DECLARED_INLINE_P (edge->callee->decl)
1128                  && DECL_DECLARED_INLINE_P (caller->decl))
1129                 /* ... or when early optimizers decided to split and edge
1130                      frequency still indicates splitting is a win ... */
1131                 || (callee->split_part && !caller->split_part
1132                       && edge->sreal_frequency () * 100
1133                          < PARAM_VALUE
1134                                 (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY)
1135                       /* ... and do not overwrite user specified hints.   */
1136                       && (!DECL_DECLARED_INLINE_P (edge->callee->decl)
1137                           || DECL_DECLARED_INLINE_P (caller->decl)))))
1138           {
1139             struct ipa_fn_summary *caller_info = ipa_fn_summaries->get (caller);
1140             int caller_growth = caller_info->growth;
1141 
1142             /* Only apply the penalty when caller looks like inline candidate,
1143                and it is not called once and.  */
1144             if (!caller_info->single_caller && overall_growth < caller_growth
1145                 && caller_info->inlinable
1146                 && caller_info->size
1147                      < (DECL_DECLARED_INLINE_P (caller->decl)
1148                         ? MAX_INLINE_INSNS_SINGLE : MAX_INLINE_INSNS_AUTO))
1149               {
1150                 if (dump)
1151                     fprintf (dump_file,
1152                                "     Wrapper penalty. Increasing growth %i to %i\n",
1153                                overall_growth, caller_growth);
1154                 overall_growth = caller_growth;
1155               }
1156           }
1157       if (overall_growth > 0)
1158         {
1159             /* Strongly preffer functions with few callers that can be inlined
1160                fully.  The square root here leads to smaller binaries at average.
1161                Watch however for extreme cases and return to linear function
1162                when growth is large.  */
1163             if (overall_growth < 256)
1164               overall_growth *= overall_growth;
1165             else
1166               overall_growth += 256 * 256 - 256;
1167             denominator *= overall_growth;
1168         }
1169       denominator *= ipa_fn_summaries->get (caller)->self_size + growth;
1170 
1171       badness = - numerator / denominator;
1172 
1173       if (dump)
1174           {
1175             fprintf (dump_file,
1176                        "      %f: guessed profile. frequency %f, count %" PRId64
1177                        " caller count %" PRId64
1178                        " time w/o inlining %f, time with inlining %f"
1179                        " overall growth %i (current) %i (original)"
1180                        " %i (compensated)\n",
1181                        badness.to_double (),
1182                        edge->sreal_frequency ().to_double (),
1183                        edge->count.ipa ().initialized_p () ? edge->count.ipa ().to_gcov_type () : -1,
1184                        caller->count.ipa ().initialized_p () ? caller->count.ipa ().to_gcov_type () : -1,
1185                        compute_uninlined_call_time (edge,
1186                                                             unspec_edge_time).to_double (),
1187                        inlined_time.to_double (),
1188                        estimate_growth (callee),
1189                        callee_info->growth, overall_growth);
1190           }
1191     }
1192   /* When function local profile is not available or it does not give
1193      useful information (ie frequency is zero), base the cost on
1194      loop nest and overall size growth, so we optimize for overall number
1195      of functions fully inlined in program.  */
1196   else
1197     {
1198       int nest = MIN (ipa_call_summaries->get (edge)->loop_depth, 8);
1199       badness = growth;
1200 
1201       /* Decrease badness if call is nested.  */
1202       if (badness > 0)
1203           badness = badness >> nest;
1204       else
1205           badness = badness << nest;
1206       if (dump)
1207           fprintf (dump_file, "      %f: no profile. nest %i\n",
1208                      badness.to_double (), nest);
1209     }
1210   gcc_checking_assert (badness != 0);
1211 
1212   if (edge->recursive_p ())
1213     badness = badness.shift (badness > 0 ? 4 : -4);
1214   if ((hints & (INLINE_HINT_indirect_call
1215                     | INLINE_HINT_loop_iterations
1216                     | INLINE_HINT_array_index
1217                     | INLINE_HINT_loop_stride))
1218       || callee_info->growth <= 0)
1219     badness = badness.shift (badness > 0 ? -2 : 2);
1220   if (hints & (INLINE_HINT_same_scc))
1221     badness = badness.shift (badness > 0 ? 3 : -3);
1222   else if (hints & (INLINE_HINT_in_scc))
1223     badness = badness.shift (badness > 0 ? 2 : -2);
1224   else if (hints & (INLINE_HINT_cross_module))
1225     badness = badness.shift (badness > 0 ? 1 : -1);
1226   if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
1227     badness = badness.shift (badness > 0 ? -4 : 4);
1228   else if ((hints & INLINE_HINT_declared_inline))
1229     badness = badness.shift (badness > 0 ? -3 : 3);
1230   if (dump)
1231     fprintf (dump_file, "      Adjusted by hints %f\n", badness.to_double ());
1232   return badness;
1233 }
1234 
1235 /* Recompute badness of EDGE and update its key in HEAP if needed.  */
1236 static inline void
update_edge_key(edge_heap_t * heap,struct cgraph_edge * edge)1237 update_edge_key (edge_heap_t *heap, struct cgraph_edge *edge)
1238 {
1239   sreal badness = edge_badness (edge, false);
1240   if (edge->aux)
1241     {
1242       edge_heap_node_t *n = (edge_heap_node_t *) edge->aux;
1243       gcc_checking_assert (n->get_data () == edge);
1244 
1245       /* fibonacci_heap::replace_key does busy updating of the
1246            heap that is unnecesarily expensive.
1247            We do lazy increases: after extracting minimum if the key
1248            turns out to be out of date, it is re-inserted into heap
1249            with correct value.  */
1250       if (badness < n->get_key ())
1251           {
1252             if (dump_file && (dump_flags & TDF_DETAILS))
1253               {
1254                 fprintf (dump_file,
1255                            "  decreasing badness %s -> %s, %f to %f\n",
1256                            edge->caller->dump_name (),
1257                            edge->callee->dump_name (),
1258                            n->get_key ().to_double (),
1259                            badness.to_double ());
1260               }
1261             heap->decrease_key (n, badness);
1262           }
1263     }
1264   else
1265     {
1266        if (dump_file && (dump_flags & TDF_DETAILS))
1267            {
1268              fprintf (dump_file,
1269                         "  enqueuing call %s -> %s, badness %f\n",
1270                         edge->caller->dump_name (),
1271                         edge->callee->dump_name (),
1272                         badness.to_double ());
1273            }
1274       edge->aux = heap->insert (badness, edge);
1275     }
1276 }
1277 
1278 
1279 /* NODE was inlined.
1280    All caller edges needs to be resetted because
1281    size estimates change. Similarly callees needs reset
1282    because better context may be known.  */
1283 
1284 static void
reset_edge_caches(struct cgraph_node * node)1285 reset_edge_caches (struct cgraph_node *node)
1286 {
1287   struct cgraph_edge *edge;
1288   struct cgraph_edge *e = node->callees;
1289   struct cgraph_node *where = node;
1290   struct ipa_ref *ref;
1291 
1292   if (where->global.inlined_to)
1293     where = where->global.inlined_to;
1294 
1295   for (edge = where->callers; edge; edge = edge->next_caller)
1296     if (edge->inline_failed)
1297       reset_edge_growth_cache (edge);
1298 
1299   FOR_EACH_ALIAS (where, ref)
1300     reset_edge_caches (dyn_cast <cgraph_node *> (ref->referring));
1301 
1302   if (!e)
1303     return;
1304 
1305   while (true)
1306     if (!e->inline_failed && e->callee->callees)
1307       e = e->callee->callees;
1308     else
1309       {
1310           if (e->inline_failed)
1311             reset_edge_growth_cache (e);
1312           if (e->next_callee)
1313             e = e->next_callee;
1314           else
1315             {
1316               do
1317                 {
1318                     if (e->caller == node)
1319                       return;
1320                     e = e->caller->callers;
1321                 }
1322               while (!e->next_callee);
1323               e = e->next_callee;
1324             }
1325       }
1326 }
1327 
1328 /* Recompute HEAP nodes for each of caller of NODE.
1329    UPDATED_NODES track nodes we already visited, to avoid redundant work.
1330    When CHECK_INLINABLITY_FOR is set, re-check for specified edge that
1331    it is inlinable. Otherwise check all edges.  */
1332 
1333 static void
update_caller_keys(edge_heap_t * heap,struct cgraph_node * node,bitmap updated_nodes,struct cgraph_edge * check_inlinablity_for)1334 update_caller_keys (edge_heap_t *heap, struct cgraph_node *node,
1335                         bitmap updated_nodes,
1336                         struct cgraph_edge *check_inlinablity_for)
1337 {
1338   struct cgraph_edge *edge;
1339   struct ipa_ref *ref;
1340 
1341   if ((!node->alias && !ipa_fn_summaries->get (node)->inlinable)
1342       || node->global.inlined_to)
1343     return;
1344   if (!bitmap_set_bit (updated_nodes, node->uid))
1345     return;
1346 
1347   FOR_EACH_ALIAS (node, ref)
1348     {
1349       struct cgraph_node *alias = dyn_cast <cgraph_node *> (ref->referring);
1350       update_caller_keys (heap, alias, updated_nodes, check_inlinablity_for);
1351     }
1352 
1353   for (edge = node->callers; edge; edge = edge->next_caller)
1354     if (edge->inline_failed)
1355       {
1356         if (!check_inlinablity_for
1357               || check_inlinablity_for == edge)
1358             {
1359               if (can_inline_edge_p (edge, false)
1360                     && want_inline_small_function_p (edge, false)
1361                     && can_inline_edge_by_limits_p (edge, false))
1362                 update_edge_key (heap, edge);
1363               else if (edge->aux)
1364                 {
1365                     report_inline_failed_reason (edge);
1366                     heap->delete_node ((edge_heap_node_t *) edge->aux);
1367                     edge->aux = NULL;
1368                 }
1369             }
1370           else if (edge->aux)
1371             update_edge_key (heap, edge);
1372       }
1373 }
1374 
1375 /* Recompute HEAP nodes for each uninlined call in NODE.
1376    This is used when we know that edge badnesses are going only to increase
1377    (we introduced new call site) and thus all we need is to insert newly
1378    created edges into heap.  */
1379 
1380 static void
update_callee_keys(edge_heap_t * heap,struct cgraph_node * node,bitmap updated_nodes)1381 update_callee_keys (edge_heap_t *heap, struct cgraph_node *node,
1382                         bitmap updated_nodes)
1383 {
1384   struct cgraph_edge *e = node->callees;
1385 
1386   if (!e)
1387     return;
1388   while (true)
1389     if (!e->inline_failed && e->callee->callees)
1390       e = e->callee->callees;
1391     else
1392       {
1393           enum availability avail;
1394           struct cgraph_node *callee;
1395           /* We do not reset callee growth cache here.  Since we added a new call,
1396              growth chould have just increased and consequentely badness metric
1397            don't need updating.  */
1398           if (e->inline_failed
1399               && (callee = e->callee->ultimate_alias_target (&avail, e->caller))
1400               && ipa_fn_summaries->get (callee)->inlinable
1401               && avail >= AVAIL_AVAILABLE
1402               && !bitmap_bit_p (updated_nodes, callee->uid))
1403             {
1404               if (can_inline_edge_p (e, false)
1405                     && want_inline_small_function_p (e, false)
1406                     && can_inline_edge_by_limits_p (e, false))
1407                 update_edge_key (heap, e);
1408               else if (e->aux)
1409                 {
1410                     report_inline_failed_reason (e);
1411                     heap->delete_node ((edge_heap_node_t *) e->aux);
1412                     e->aux = NULL;
1413                 }
1414             }
1415           if (e->next_callee)
1416             e = e->next_callee;
1417           else
1418             {
1419               do
1420                 {
1421                     if (e->caller == node)
1422                       return;
1423                     e = e->caller->callers;
1424                 }
1425               while (!e->next_callee);
1426               e = e->next_callee;
1427             }
1428       }
1429 }
1430 
1431 /* Enqueue all recursive calls from NODE into priority queue depending on
1432    how likely we want to recursively inline the call.  */
1433 
1434 static void
lookup_recursive_calls(struct cgraph_node * node,struct cgraph_node * where,edge_heap_t * heap)1435 lookup_recursive_calls (struct cgraph_node *node, struct cgraph_node *where,
1436                               edge_heap_t *heap)
1437 {
1438   struct cgraph_edge *e;
1439   enum availability avail;
1440 
1441   for (e = where->callees; e; e = e->next_callee)
1442     if (e->callee == node
1443           || (e->callee->ultimate_alias_target (&avail, e->caller) == node
1444               && avail > AVAIL_INTERPOSABLE))
1445       heap->insert (-e->sreal_frequency (), e);
1446   for (e = where->callees; e; e = e->next_callee)
1447     if (!e->inline_failed)
1448       lookup_recursive_calls (node, e->callee, heap);
1449 }
1450 
1451 /* Decide on recursive inlining: in the case function has recursive calls,
1452    inline until body size reaches given argument.  If any new indirect edges
1453    are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES
1454    is NULL.  */
1455 
1456 static bool
recursive_inlining(struct cgraph_edge * edge,vec<cgraph_edge * > * new_edges)1457 recursive_inlining (struct cgraph_edge *edge,
1458                         vec<cgraph_edge *> *new_edges)
1459 {
1460   int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO);
1461   edge_heap_t heap (sreal::min ());
1462   struct cgraph_node *node;
1463   struct cgraph_edge *e;
1464   struct cgraph_node *master_clone = NULL, *next;
1465   int depth = 0;
1466   int n = 0;
1467 
1468   node = edge->caller;
1469   if (node->global.inlined_to)
1470     node = node->global.inlined_to;
1471 
1472   if (DECL_DECLARED_INLINE_P (node->decl))
1473     limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE);
1474 
1475   /* Make sure that function is small enough to be considered for inlining.  */
1476   if (estimate_size_after_inlining (node, edge)  >= limit)
1477     return false;
1478   lookup_recursive_calls (node, node, &heap);
1479   if (heap.empty ())
1480     return false;
1481 
1482   if (dump_file)
1483     fprintf (dump_file,
1484                "  Performing recursive inlining on %s\n",
1485                node->name ());
1486 
1487   /* Do the inlining and update list of recursive call during process.  */
1488   while (!heap.empty ())
1489     {
1490       struct cgraph_edge *curr = heap.extract_min ();
1491       struct cgraph_node *cnode, *dest = curr->callee;
1492 
1493       if (!can_inline_edge_p (curr, true)
1494             || can_inline_edge_by_limits_p (curr, true))
1495           continue;
1496 
1497       /* MASTER_CLONE is produced in the case we already started modified
1498            the function. Be sure to redirect edge to the original body before
1499            estimating growths otherwise we will be seeing growths after inlining
1500            the already modified body.  */
1501       if (master_clone)
1502           {
1503             curr->redirect_callee (master_clone);
1504             reset_edge_growth_cache (curr);
1505           }
1506 
1507       if (estimate_size_after_inlining (node, curr) > limit)
1508           {
1509             curr->redirect_callee (dest);
1510             reset_edge_growth_cache (curr);
1511             break;
1512           }
1513 
1514       depth = 1;
1515       for (cnode = curr->caller;
1516              cnode->global.inlined_to; cnode = cnode->callers->caller)
1517           if (node->decl
1518               == curr->callee->ultimate_alias_target ()->decl)
1519           depth++;
1520 
1521       if (!want_inline_self_recursive_call_p (curr, node, false, depth))
1522           {
1523             curr->redirect_callee (dest);
1524             reset_edge_growth_cache (curr);
1525             continue;
1526           }
1527 
1528       if (dump_file)
1529           {
1530             fprintf (dump_file,
1531                        "   Inlining call of depth %i", depth);
1532             if (node->count.nonzero_p ())
1533               {
1534                 fprintf (dump_file, " called approx. %.2f times per call",
1535                            (double)curr->count.to_gcov_type ()
1536                            / node->count.to_gcov_type ());
1537               }
1538             fprintf (dump_file, "\n");
1539           }
1540       if (!master_clone)
1541           {
1542             /* We need original clone to copy around.  */
1543             master_clone = node->create_clone (node->decl, node->count,
1544               false, vNULL, true, NULL, NULL);
1545             for (e = master_clone->callees; e; e = e->next_callee)
1546               if (!e->inline_failed)
1547                 clone_inlined_nodes (e, true, false, NULL);
1548             curr->redirect_callee (master_clone);
1549           reset_edge_growth_cache (curr);
1550           }
1551 
1552       inline_call (curr, false, new_edges, &overall_size, true);
1553       lookup_recursive_calls (node, curr->callee, &heap);
1554       n++;
1555     }
1556 
1557   if (!heap.empty () && dump_file)
1558     fprintf (dump_file, "    Recursive inlining growth limit met.\n");
1559 
1560   if (!master_clone)
1561     return false;
1562 
1563   if (dump_file)
1564     fprintf (dump_file,
1565                "\n   Inlined %i times, "
1566                "body grown from size %i to %i, time %f to %f\n", n,
1567                ipa_fn_summaries->get (master_clone)->size,
1568                ipa_fn_summaries->get (node)->size,
1569                ipa_fn_summaries->get (master_clone)->time.to_double (),
1570                ipa_fn_summaries->get (node)->time.to_double ());
1571 
1572   /* Remove master clone we used for inlining.  We rely that clones inlined
1573      into master clone gets queued just before master clone so we don't
1574      need recursion.  */
1575   for (node = symtab->first_function (); node != master_clone;
1576        node = next)
1577     {
1578       next = symtab->next_function (node);
1579       if (node->global.inlined_to == master_clone)
1580           node->remove ();
1581     }
1582   master_clone->remove ();
1583   return true;
1584 }
1585 
1586 
1587 /* Given whole compilation unit estimate of INSNS, compute how large we can
1588    allow the unit to grow.  */
1589 
1590 static int
compute_max_insns(int insns)1591 compute_max_insns (int insns)
1592 {
1593   int max_insns = insns;
1594   if (max_insns < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
1595     max_insns = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
1596 
1597   return ((int64_t) max_insns
1598             * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100);
1599 }
1600 
1601 
1602 /* Compute badness of all edges in NEW_EDGES and add them to the HEAP.  */
1603 
1604 static void
add_new_edges_to_heap(edge_heap_t * heap,vec<cgraph_edge * > new_edges)1605 add_new_edges_to_heap (edge_heap_t *heap, vec<cgraph_edge *> new_edges)
1606 {
1607   while (new_edges.length () > 0)
1608     {
1609       struct cgraph_edge *edge = new_edges.pop ();
1610 
1611       gcc_assert (!edge->aux);
1612       if (edge->inline_failed
1613             && can_inline_edge_p (edge, true)
1614             && want_inline_small_function_p (edge, true)
1615             && can_inline_edge_by_limits_p (edge, true))
1616         edge->aux = heap->insert (edge_badness (edge, false), edge);
1617     }
1618 }
1619 
1620 /* Remove EDGE from the fibheap.  */
1621 
1622 static void
heap_edge_removal_hook(struct cgraph_edge * e,void * data)1623 heap_edge_removal_hook (struct cgraph_edge *e, void *data)
1624 {
1625   if (e->aux)
1626     {
1627       ((edge_heap_t *)data)->delete_node ((edge_heap_node_t *)e->aux);
1628       e->aux = NULL;
1629     }
1630 }
1631 
1632 /* Return true if speculation of edge E seems useful.
1633    If ANTICIPATE_INLINING is true, be conservative and hope that E
1634    may get inlined.  */
1635 
1636 bool
speculation_useful_p(struct cgraph_edge * e,bool anticipate_inlining)1637 speculation_useful_p (struct cgraph_edge *e, bool anticipate_inlining)
1638 {
1639   enum availability avail;
1640   struct cgraph_node *target = e->callee->ultimate_alias_target (&avail,
1641                                                                                  e->caller);
1642   struct cgraph_edge *direct, *indirect;
1643   struct ipa_ref *ref;
1644 
1645   gcc_assert (e->speculative && !e->indirect_unknown_callee);
1646 
1647   if (!e->maybe_hot_p ())
1648     return false;
1649 
1650   /* See if IP optimizations found something potentially useful about the
1651      function.  For now we look only for CONST/PURE flags.  Almost everything
1652      else we propagate is useless.  */
1653   if (avail >= AVAIL_AVAILABLE)
1654     {
1655       int ecf_flags = flags_from_decl_or_type (target->decl);
1656       if (ecf_flags & ECF_CONST)
1657         {
1658             e->speculative_call_info (direct, indirect, ref);
1659             if (!(indirect->indirect_info->ecf_flags & ECF_CONST))
1660               return true;
1661         }
1662       else if (ecf_flags & ECF_PURE)
1663         {
1664             e->speculative_call_info (direct, indirect, ref);
1665             if (!(indirect->indirect_info->ecf_flags & ECF_PURE))
1666               return true;
1667         }
1668     }
1669   /* If we did not managed to inline the function nor redirect
1670      to an ipa-cp clone (that are seen by having local flag set),
1671      it is probably pointless to inline it unless hardware is missing
1672      indirect call predictor.  */
1673   if (!anticipate_inlining && e->inline_failed && !target->local.local)
1674     return false;
1675   /* For overwritable targets there is not much to do.  */
1676   if (e->inline_failed
1677       && (!can_inline_edge_p (e, false)
1678             || !can_inline_edge_by_limits_p (e, false, true)))
1679     return false;
1680   /* OK, speculation seems interesting.  */
1681   return true;
1682 }
1683 
1684 /* We know that EDGE is not going to be inlined.
1685    See if we can remove speculation.  */
1686 
1687 static void
resolve_noninline_speculation(edge_heap_t * edge_heap,struct cgraph_edge * edge)1688 resolve_noninline_speculation (edge_heap_t *edge_heap, struct cgraph_edge *edge)
1689 {
1690   if (edge->speculative && !speculation_useful_p (edge, false))
1691     {
1692       struct cgraph_node *node = edge->caller;
1693       struct cgraph_node *where = node->global.inlined_to
1694                                           ? node->global.inlined_to : node;
1695       auto_bitmap updated_nodes;
1696 
1697       if (edge->count.ipa ().initialized_p ())
1698         spec_rem += edge->count.ipa ();
1699       edge->resolve_speculation ();
1700       reset_edge_caches (where);
1701       ipa_update_overall_fn_summary (where);
1702       update_caller_keys (edge_heap, where,
1703                                 updated_nodes, NULL);
1704       update_callee_keys (edge_heap, where,
1705                                 updated_nodes);
1706     }
1707 }
1708 
1709 /* Return true if NODE should be accounted for overall size estimate.
1710    Skip all nodes optimized for size so we can measure the growth of hot
1711    part of program no matter of the padding.  */
1712 
1713 bool
inline_account_function_p(struct cgraph_node * node)1714 inline_account_function_p (struct cgraph_node *node)
1715 {
1716    return (!DECL_EXTERNAL (node->decl)
1717              && !opt_for_fn (node->decl, optimize_size)
1718              && node->frequency != NODE_FREQUENCY_UNLIKELY_EXECUTED);
1719 }
1720 
1721 /* Count number of callers of NODE and store it into DATA (that
1722    points to int.  Worker for cgraph_for_node_and_aliases.  */
1723 
1724 static bool
sum_callers(struct cgraph_node * node,void * data)1725 sum_callers (struct cgraph_node *node, void *data)
1726 {
1727   struct cgraph_edge *e;
1728   int *num_calls = (int *)data;
1729 
1730   for (e = node->callers; e; e = e->next_caller)
1731     (*num_calls)++;
1732   return false;
1733 }
1734 
1735 /* We use greedy algorithm for inlining of small functions:
1736    All inline candidates are put into prioritized heap ordered in
1737    increasing badness.
1738 
1739    The inlining of small functions is bounded by unit growth parameters.  */
1740 
1741 static void
inline_small_functions(void)1742 inline_small_functions (void)
1743 {
1744   struct cgraph_node *node;
1745   struct cgraph_edge *edge;
1746   edge_heap_t edge_heap (sreal::min ());
1747   auto_bitmap updated_nodes;
1748   int min_size, max_size;
1749   auto_vec<cgraph_edge *> new_indirect_edges;
1750   int initial_size = 0;
1751   struct cgraph_node **order = XCNEWVEC (cgraph_node *, symtab->cgraph_count);
1752   struct cgraph_edge_hook_list *edge_removal_hook_holder;
1753   new_indirect_edges.create (8);
1754 
1755   edge_removal_hook_holder
1756     = symtab->add_edge_removal_hook (&heap_edge_removal_hook, &edge_heap);
1757 
1758   /* Compute overall unit size and other global parameters used by badness
1759      metrics.  */
1760 
1761   max_count = profile_count::uninitialized ();
1762   ipa_reduced_postorder (order, true, NULL);
1763   free (order);
1764 
1765   FOR_EACH_DEFINED_FUNCTION (node)
1766     if (!node->global.inlined_to)
1767       {
1768           if (!node->alias && node->analyzed
1769               && (node->has_gimple_body_p () || node->thunk.thunk_p)
1770               && opt_for_fn (node->decl, optimize))
1771             {
1772               struct ipa_fn_summary *info = ipa_fn_summaries->get (node);
1773               struct ipa_dfs_info *dfs = (struct ipa_dfs_info *) node->aux;
1774 
1775               /* Do not account external functions, they will be optimized out
1776                  if not inlined.  Also only count the non-cold portion of program.  */
1777               if (inline_account_function_p (node))
1778                 initial_size += info->size;
1779               info->growth = estimate_growth (node);
1780 
1781               int num_calls = 0;
1782               node->call_for_symbol_and_aliases (sum_callers, &num_calls,
1783                                                          true);
1784               if (num_calls == 1)
1785                 info->single_caller = true;
1786               if (dfs && dfs->next_cycle)
1787                 {
1788                     struct cgraph_node *n2;
1789                     int id = dfs->scc_no + 1;
1790                     for (n2 = node; n2;
1791                          n2 = ((struct ipa_dfs_info *) n2->aux)->next_cycle)
1792                       if (opt_for_fn (n2->decl, optimize))
1793                         {
1794                           struct ipa_fn_summary *info2 = ipa_fn_summaries->get (n2);
1795                           if (info2->scc_no)
1796                               break;
1797                           info2->scc_no = id;
1798                         }
1799                 }
1800             }
1801 
1802           for (edge = node->callers; edge; edge = edge->next_caller)
1803             max_count = max_count.max (edge->count.ipa ());
1804       }
1805   ipa_free_postorder_info ();
1806   initialize_growth_caches ();
1807 
1808   if (dump_file)
1809     fprintf (dump_file,
1810                "\nDeciding on inlining of small functions.  Starting with size %i.\n",
1811                initial_size);
1812 
1813   overall_size = initial_size;
1814   max_size = compute_max_insns (overall_size);
1815   min_size = overall_size;
1816 
1817   /* Populate the heap with all edges we might inline.  */
1818 
1819   FOR_EACH_DEFINED_FUNCTION (node)
1820     {
1821       bool update = false;
1822       struct cgraph_edge *next = NULL;
1823       bool has_speculative = false;
1824 
1825       if (!opt_for_fn (node->decl, optimize))
1826           continue;
1827 
1828       if (dump_file)
1829           fprintf (dump_file, "Enqueueing calls in %s.\n", node->dump_name ());
1830 
1831       for (edge = node->callees; edge; edge = next)
1832           {
1833             next = edge->next_callee;
1834             if (edge->inline_failed
1835                 && !edge->aux
1836                 && can_inline_edge_p (edge, true)
1837                 && want_inline_small_function_p (edge, true)
1838                 && can_inline_edge_by_limits_p (edge, true)
1839                 && edge->inline_failed)
1840               {
1841                 gcc_assert (!edge->aux);
1842                 update_edge_key (&edge_heap, edge);
1843               }
1844             if (edge->speculative)
1845               has_speculative = true;
1846           }
1847       if (has_speculative)
1848           for (edge = node->callees; edge; edge = next)
1849             if (edge->speculative && !speculation_useful_p (edge,
1850                                                                         edge->aux != NULL))
1851               {
1852                 edge->resolve_speculation ();
1853                 update = true;
1854               }
1855       if (update)
1856           {
1857             struct cgraph_node *where = node->global.inlined_to
1858                                               ? node->global.inlined_to : node;
1859             ipa_update_overall_fn_summary (where);
1860             reset_edge_caches (where);
1861           update_caller_keys (&edge_heap, where,
1862                                     updated_nodes, NULL);
1863           update_callee_keys (&edge_heap, where,
1864                                     updated_nodes);
1865           bitmap_clear (updated_nodes);
1866           }
1867     }
1868 
1869   gcc_assert (in_lto_p
1870                 || !(max_count > 0)
1871                 || (profile_info && flag_branch_probabilities));
1872 
1873   while (!edge_heap.empty ())
1874     {
1875       int old_size = overall_size;
1876       struct cgraph_node *where, *callee;
1877       sreal badness = edge_heap.min_key ();
1878       sreal current_badness;
1879       int growth;
1880 
1881       edge = edge_heap.extract_min ();
1882       gcc_assert (edge->aux);
1883       edge->aux = NULL;
1884       if (!edge->inline_failed || !edge->callee->analyzed)
1885           continue;
1886 
1887 #if CHECKING_P
1888       /* Be sure that caches are maintained consistent.
1889            This check is affected by scaling roundoff errors when compiling for
1890            IPA this we skip it in that case.  */
1891       if (!edge->callee->count.ipa_p ()
1892             && (!max_count.initialized_p () || !max_count.nonzero_p ()))
1893           {
1894             sreal cached_badness = edge_badness (edge, false);
1895 
1896             int old_size_est = estimate_edge_size (edge);
1897             sreal old_time_est = estimate_edge_time (edge);
1898             int old_hints_est = estimate_edge_hints (edge);
1899 
1900             reset_edge_growth_cache (edge);
1901             gcc_assert (old_size_est == estimate_edge_size (edge));
1902             gcc_assert (old_time_est == estimate_edge_time (edge));
1903             /* FIXME:
1904 
1905                gcc_assert (old_hints_est == estimate_edge_hints (edge));
1906 
1907                fails with profile feedback because some hints depends on
1908                maybe_hot_edge_p predicate and because callee gets inlined to other
1909                calls, the edge may become cold.
1910                This ought to be fixed by computing relative probabilities
1911                for given invocation but that will be better done once whole
1912                code is converted to sreals.  Disable for now and revert to "wrong"
1913                value so enable/disable checking paths agree.  */
1914             edge_growth_cache[edge->uid].hints = old_hints_est + 1;
1915 
1916             /* When updating the edge costs, we only decrease badness in the keys.
1917                Increases of badness are handled lazilly; when we see key with out
1918                of date value on it, we re-insert it now.  */
1919             current_badness = edge_badness (edge, false);
1920             gcc_assert (cached_badness == current_badness);
1921             gcc_assert (current_badness >= badness);
1922           }
1923       else
1924         current_badness = edge_badness (edge, false);
1925 #else
1926       current_badness = edge_badness (edge, false);
1927 #endif
1928       if (current_badness != badness)
1929           {
1930             if (edge_heap.min () && current_badness > edge_heap.min_key ())
1931               {
1932                 edge->aux = edge_heap.insert (current_badness, edge);
1933                 continue;
1934               }
1935             else
1936               badness = current_badness;
1937           }
1938 
1939       if (!can_inline_edge_p (edge, true)
1940             || !can_inline_edge_by_limits_p (edge, true))
1941           {
1942             resolve_noninline_speculation (&edge_heap, edge);
1943             continue;
1944           }
1945 
1946       callee = edge->callee->ultimate_alias_target ();
1947       growth = estimate_edge_growth (edge);
1948       if (dump_file)
1949           {
1950             fprintf (dump_file,
1951                        "\nConsidering %s with %i size\n",
1952                        callee->dump_name (),
1953                        ipa_fn_summaries->get (callee)->size);
1954             fprintf (dump_file,
1955                        " to be inlined into %s in %s:%i\n"
1956                        " Estimated badness is %f, frequency %.2f.\n",
1957                        edge->caller->dump_name (),
1958                        edge->call_stmt
1959                        && (LOCATION_LOCUS (gimple_location ((const gimple *)
1960                                                                       edge->call_stmt))
1961                            > BUILTINS_LOCATION)
1962                        ? gimple_filename ((const gimple *) edge->call_stmt)
1963                        : "unknown",
1964                        edge->call_stmt
1965                        ? gimple_lineno ((const gimple *) edge->call_stmt)
1966                        : -1,
1967                        badness.to_double (),
1968                        edge->sreal_frequency ().to_double ());
1969             if (edge->count.ipa ().initialized_p ())
1970               {
1971                 fprintf (dump_file, " Called ");
1972                 edge->count.ipa ().dump (dump_file);
1973                 fprintf (dump_file, " times\n");
1974             }
1975             if (dump_flags & TDF_DETAILS)
1976               edge_badness (edge, true);
1977           }
1978 
1979       if (overall_size + growth > max_size
1980             && !DECL_DISREGARD_INLINE_LIMITS (callee->decl))
1981           {
1982             edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT;
1983             report_inline_failed_reason (edge);
1984             resolve_noninline_speculation (&edge_heap, edge);
1985             continue;
1986           }
1987 
1988       if (!want_inline_small_function_p (edge, true))
1989           {
1990             resolve_noninline_speculation (&edge_heap, edge);
1991             continue;
1992           }
1993 
1994       /* Heuristics for inlining small functions work poorly for
1995            recursive calls where we do effects similar to loop unrolling.
1996            When inlining such edge seems profitable, leave decision on
1997            specific inliner.  */
1998       if (edge->recursive_p ())
1999           {
2000             where = edge->caller;
2001             if (where->global.inlined_to)
2002               where = where->global.inlined_to;
2003             if (!recursive_inlining (edge,
2004                                            opt_for_fn (edge->caller->decl,
2005                                                          flag_indirect_inlining)
2006                                            ? &new_indirect_edges : NULL))
2007               {
2008                 edge->inline_failed = CIF_RECURSIVE_INLINING;
2009                 resolve_noninline_speculation (&edge_heap, edge);
2010                 continue;
2011               }
2012             reset_edge_caches (where);
2013             /* Recursive inliner inlines all recursive calls of the function
2014                at once. Consequently we need to update all callee keys.  */
2015             if (opt_for_fn (edge->caller->decl, flag_indirect_inlining))
2016               add_new_edges_to_heap (&edge_heap, new_indirect_edges);
2017           update_callee_keys (&edge_heap, where, updated_nodes);
2018             bitmap_clear (updated_nodes);
2019           }
2020       else
2021           {
2022             struct cgraph_node *outer_node = NULL;
2023             int depth = 0;
2024 
2025             /* Consider the case where self recursive function A is inlined
2026                into B.  This is desired optimization in some cases, since it
2027                leads to effect similar of loop peeling and we might completely
2028                optimize out the recursive call.  However we must be extra
2029                selective.  */
2030 
2031             where = edge->caller;
2032             while (where->global.inlined_to)
2033               {
2034                 if (where->decl == callee->decl)
2035                     outer_node = where, depth++;
2036                 where = where->callers->caller;
2037               }
2038             if (outer_node
2039                 && !want_inline_self_recursive_call_p (edge, outer_node,
2040                                                                  true, depth))
2041               {
2042                 edge->inline_failed
2043                     = (DECL_DISREGARD_INLINE_LIMITS (edge->callee->decl)
2044                        ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
2045                 resolve_noninline_speculation (&edge_heap, edge);
2046                 continue;
2047               }
2048             else if (depth && dump_file)
2049               fprintf (dump_file, " Peeling recursion with depth %i\n", depth);
2050 
2051             gcc_checking_assert (!callee->global.inlined_to);
2052             inline_call (edge, true, &new_indirect_edges, &overall_size, true);
2053             add_new_edges_to_heap (&edge_heap, new_indirect_edges);
2054 
2055             reset_edge_caches (edge->callee);
2056 
2057             update_callee_keys (&edge_heap, where, updated_nodes);
2058           }
2059       where = edge->caller;
2060       if (where->global.inlined_to)
2061           where = where->global.inlined_to;
2062 
2063       /* Our profitability metric can depend on local properties
2064            such as number of inlinable calls and size of the function body.
2065            After inlining these properties might change for the function we
2066            inlined into (since it's body size changed) and for the functions
2067            called by function we inlined (since number of it inlinable callers
2068            might change).  */
2069       update_caller_keys (&edge_heap, where, updated_nodes, NULL);
2070       /* Offline copy count has possibly changed, recompute if profile is
2071            available.  */
2072       struct cgraph_node *n = cgraph_node::get (edge->callee->decl);
2073       if (n != edge->callee && n->analyzed && n->count.ipa ().initialized_p ())
2074           update_callee_keys (&edge_heap, n, updated_nodes);
2075       bitmap_clear (updated_nodes);
2076 
2077       if (dump_file)
2078           {
2079             fprintf (dump_file,
2080                        " Inlined %s into %s which now has time %f and size %i, "
2081                        "net change of %+i.\n",
2082                        xstrdup_for_dump (edge->callee->name ()),
2083                        xstrdup_for_dump (edge->caller->name ()),
2084                        ipa_fn_summaries->get (edge->caller)->time.to_double (),
2085                        ipa_fn_summaries->get (edge->caller)->size,
2086                        overall_size - old_size);
2087           }
2088       if (min_size > overall_size)
2089           {
2090             min_size = overall_size;
2091             max_size = compute_max_insns (min_size);
2092 
2093             if (dump_file)
2094               fprintf (dump_file, "New minimal size reached: %i\n", min_size);
2095           }
2096     }
2097 
2098   free_growth_caches ();
2099   if (dump_file)
2100     fprintf (dump_file,
2101                "Unit growth for small function inlining: %i->%i (%i%%)\n",
2102                initial_size, overall_size,
2103                initial_size ? overall_size * 100 / (initial_size) - 100: 0);
2104   symtab->remove_edge_removal_hook (edge_removal_hook_holder);
2105 }
2106 
2107 /* Flatten NODE.  Performed both during early inlining and
2108    at IPA inlining time.  */
2109 
2110 static void
flatten_function(struct cgraph_node * node,bool early)2111 flatten_function (struct cgraph_node *node, bool early)
2112 {
2113   struct cgraph_edge *e;
2114 
2115   /* We shouldn't be called recursively when we are being processed.  */
2116   gcc_assert (node->aux == NULL);
2117 
2118   node->aux = (void *) node;
2119 
2120   for (e = node->callees; e; e = e->next_callee)
2121     {
2122       struct cgraph_node *orig_callee;
2123       struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2124 
2125       /* We've hit cycle?  It is time to give up.  */
2126       if (callee->aux)
2127           {
2128             if (dump_file)
2129               fprintf (dump_file,
2130                          "Not inlining %s into %s to avoid cycle.\n",
2131                          xstrdup_for_dump (callee->name ()),
2132                          xstrdup_for_dump (e->caller->name ()));
2133             if (cgraph_inline_failed_type (e->inline_failed) != CIF_FINAL_ERROR)
2134               e->inline_failed = CIF_RECURSIVE_INLINING;
2135             continue;
2136           }
2137 
2138       /* When the edge is already inlined, we just need to recurse into
2139            it in order to fully flatten the leaves.  */
2140       if (!e->inline_failed)
2141           {
2142             flatten_function (callee, early);
2143             continue;
2144           }
2145 
2146       /* Flatten attribute needs to be processed during late inlining. For
2147            extra code quality we however do flattening during early optimization,
2148            too.  */
2149       if (!early
2150             ? !can_inline_edge_p (e, true)
2151               && !can_inline_edge_by_limits_p (e, true)
2152             : !can_early_inline_edge_p (e))
2153           continue;
2154 
2155       if (e->recursive_p ())
2156           {
2157             if (dump_file)
2158               fprintf (dump_file, "Not inlining: recursive call.\n");
2159             continue;
2160           }
2161 
2162       if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl))
2163             != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
2164           {
2165             if (dump_file)
2166               fprintf (dump_file, "Not inlining: SSA form does not match.\n");
2167             continue;
2168           }
2169 
2170       /* Inline the edge and flatten the inline clone.  Avoid
2171          recursing through the original node if the node was cloned.  */
2172       if (dump_file)
2173           fprintf (dump_file, " Inlining %s into %s.\n",
2174                      xstrdup_for_dump (callee->name ()),
2175                      xstrdup_for_dump (e->caller->name ()));
2176       orig_callee = callee;
2177       inline_call (e, true, NULL, NULL, false);
2178       if (e->callee != orig_callee)
2179           orig_callee->aux = (void *) node;
2180       flatten_function (e->callee, early);
2181       if (e->callee != orig_callee)
2182           orig_callee->aux = NULL;
2183     }
2184 
2185   node->aux = NULL;
2186   if (!node->global.inlined_to)
2187     ipa_update_overall_fn_summary (node);
2188 }
2189 
2190 /* Inline NODE to all callers.  Worker for cgraph_for_node_and_aliases.
2191    DATA points to number of calls originally found so we avoid infinite
2192    recursion.  */
2193 
2194 static bool
inline_to_all_callers_1(struct cgraph_node * node,void * data,hash_set<cgraph_node * > * callers)2195 inline_to_all_callers_1 (struct cgraph_node *node, void *data,
2196                                hash_set<cgraph_node *> *callers)
2197 {
2198   int *num_calls = (int *)data;
2199   bool callee_removed = false;
2200 
2201   while (node->callers && !node->global.inlined_to)
2202     {
2203       struct cgraph_node *caller = node->callers->caller;
2204 
2205       if (!can_inline_edge_p (node->callers, true)
2206             || !can_inline_edge_by_limits_p (node->callers, true)
2207             || node->callers->recursive_p ())
2208           {
2209             if (dump_file)
2210               fprintf (dump_file, "Uninlinable call found; giving up.\n");
2211             *num_calls = 0;
2212             return false;
2213           }
2214 
2215       if (dump_file)
2216           {
2217             fprintf (dump_file,
2218                        "\nInlining %s size %i.\n",
2219                        node->name (),
2220                        ipa_fn_summaries->get (node)->size);
2221             fprintf (dump_file,
2222                        " Called once from %s %i insns.\n",
2223                        node->callers->caller->name (),
2224                        ipa_fn_summaries->get (node->callers->caller)->size);
2225           }
2226 
2227       /* Remember which callers we inlined to, delaying updating the
2228            overall summary.  */
2229       callers->add (node->callers->caller);
2230       inline_call (node->callers, true, NULL, NULL, false, &callee_removed);
2231       if (dump_file)
2232           fprintf (dump_file,
2233                      " Inlined into %s which now has %i size\n",
2234                      caller->name (),
2235                      ipa_fn_summaries->get (caller)->size);
2236       if (!(*num_calls)--)
2237           {
2238             if (dump_file)
2239               fprintf (dump_file, "New calls found; giving up.\n");
2240             return callee_removed;
2241           }
2242       if (callee_removed)
2243           return true;
2244     }
2245   return false;
2246 }
2247 
2248 /* Wrapper around inline_to_all_callers_1 doing delayed overall summary
2249    update.  */
2250 
2251 static bool
inline_to_all_callers(struct cgraph_node * node,void * data)2252 inline_to_all_callers (struct cgraph_node *node, void *data)
2253 {
2254   hash_set<cgraph_node *> callers;
2255   bool res = inline_to_all_callers_1 (node, data, &callers);
2256   /* Perform the delayed update of the overall summary of all callers
2257      processed.  This avoids quadratic behavior in the cases where
2258      we have a lot of calls to the same function.  */
2259   for (hash_set<cgraph_node *>::iterator i = callers.begin ();
2260        i != callers.end (); ++i)
2261     ipa_update_overall_fn_summary (*i);
2262   return res;
2263 }
2264 
2265 /* Output overall time estimate.  */
2266 static void
dump_overall_stats(void)2267 dump_overall_stats (void)
2268 {
2269   sreal sum_weighted = 0, sum = 0;
2270   struct cgraph_node *node;
2271 
2272   FOR_EACH_DEFINED_FUNCTION (node)
2273     if (!node->global.inlined_to
2274           && !node->alias)
2275       {
2276           sreal time = ipa_fn_summaries->get (node)->time;
2277           sum += time;
2278           if (node->count.ipa ().initialized_p ())
2279             sum_weighted += time * node->count.ipa ().to_gcov_type ();
2280       }
2281   fprintf (dump_file, "Overall time estimate: "
2282              "%f weighted by profile: "
2283              "%f\n", sum.to_double (), sum_weighted.to_double ());
2284 }
2285 
2286 /* Output some useful stats about inlining.  */
2287 
2288 static void
dump_inline_stats(void)2289 dump_inline_stats (void)
2290 {
2291   int64_t inlined_cnt = 0, inlined_indir_cnt = 0;
2292   int64_t inlined_virt_cnt = 0, inlined_virt_indir_cnt = 0;
2293   int64_t noninlined_cnt = 0, noninlined_indir_cnt = 0;
2294   int64_t noninlined_virt_cnt = 0, noninlined_virt_indir_cnt = 0;
2295   int64_t  inlined_speculative = 0, inlined_speculative_ply = 0;
2296   int64_t indirect_poly_cnt = 0, indirect_cnt = 0;
2297   int64_t reason[CIF_N_REASONS][2];
2298   sreal reason_freq[CIF_N_REASONS];
2299   int i;
2300   struct cgraph_node *node;
2301 
2302   memset (reason, 0, sizeof (reason));
2303   for (i=0; i < CIF_N_REASONS; i++)
2304     reason_freq[i] = 0;
2305   FOR_EACH_DEFINED_FUNCTION (node)
2306   {
2307     struct cgraph_edge *e;
2308     for (e = node->callees; e; e = e->next_callee)
2309       {
2310           if (e->inline_failed)
2311             {
2312               if (e->count.ipa ().initialized_p ())
2313                 reason[(int) e->inline_failed][0] += e->count.ipa ().to_gcov_type ();
2314               reason_freq[(int) e->inline_failed] += e->sreal_frequency ();
2315               reason[(int) e->inline_failed][1] ++;
2316               if (DECL_VIRTUAL_P (e->callee->decl)
2317                     && e->count.ipa ().initialized_p ())
2318                 {
2319                     if (e->indirect_inlining_edge)
2320                       noninlined_virt_indir_cnt += e->count.ipa ().to_gcov_type ();
2321                     else
2322                       noninlined_virt_cnt += e->count.ipa ().to_gcov_type ();
2323                 }
2324               else if (e->count.ipa ().initialized_p ())
2325                 {
2326                     if (e->indirect_inlining_edge)
2327                       noninlined_indir_cnt += e->count.ipa ().to_gcov_type ();
2328                     else
2329                       noninlined_cnt += e->count.ipa ().to_gcov_type ();
2330                 }
2331             }
2332           else if (e->count.ipa ().initialized_p ())
2333             {
2334               if (e->speculative)
2335                 {
2336                     if (DECL_VIRTUAL_P (e->callee->decl))
2337                       inlined_speculative_ply += e->count.ipa ().to_gcov_type ();
2338                     else
2339                       inlined_speculative += e->count.ipa ().to_gcov_type ();
2340                 }
2341               else if (DECL_VIRTUAL_P (e->callee->decl))
2342                 {
2343                     if (e->indirect_inlining_edge)
2344                       inlined_virt_indir_cnt += e->count.ipa ().to_gcov_type ();
2345                     else
2346                       inlined_virt_cnt += e->count.ipa ().to_gcov_type ();
2347                 }
2348               else
2349                 {
2350                     if (e->indirect_inlining_edge)
2351                       inlined_indir_cnt += e->count.ipa ().to_gcov_type ();
2352                     else
2353                       inlined_cnt += e->count.ipa ().to_gcov_type ();
2354                 }
2355             }
2356       }
2357     for (e = node->indirect_calls; e; e = e->next_callee)
2358       if (e->indirect_info->polymorphic
2359             & e->count.ipa ().initialized_p ())
2360           indirect_poly_cnt += e->count.ipa ().to_gcov_type ();
2361       else if (e->count.ipa ().initialized_p ())
2362           indirect_cnt += e->count.ipa ().to_gcov_type ();
2363   }
2364   if (max_count.initialized_p ())
2365     {
2366       fprintf (dump_file,
2367                  "Inlined %" PRId64 " + speculative "
2368                  "%" PRId64 " + speculative polymorphic "
2369                  "%" PRId64 " + previously indirect "
2370                  "%" PRId64 " + virtual "
2371                  "%" PRId64 " + virtual and previously indirect "
2372                  "%" PRId64 "\n" "Not inlined "
2373                  "%" PRId64 " + previously indirect "
2374                  "%" PRId64 " + virtual "
2375                  "%" PRId64 " + virtual and previously indirect "
2376                  "%" PRId64 " + stil indirect "
2377                  "%" PRId64 " + still indirect polymorphic "
2378                  "%" PRId64 "\n", inlined_cnt,
2379                  inlined_speculative, inlined_speculative_ply,
2380                  inlined_indir_cnt, inlined_virt_cnt, inlined_virt_indir_cnt,
2381                  noninlined_cnt, noninlined_indir_cnt, noninlined_virt_cnt,
2382                  noninlined_virt_indir_cnt, indirect_cnt, indirect_poly_cnt);
2383       fprintf (dump_file, "Removed speculations ");
2384       spec_rem.dump (dump_file);
2385       fprintf (dump_file, "\n");
2386     }
2387   dump_overall_stats ();
2388   fprintf (dump_file, "\nWhy inlining failed?\n");
2389   for (i = 0; i < CIF_N_REASONS; i++)
2390     if (reason[i][1])
2391       fprintf (dump_file, "%-50s: %8i calls, %8f freq, %" PRId64" count\n",
2392                  cgraph_inline_failed_string ((cgraph_inline_failed_t) i),
2393                  (int) reason[i][1], reason_freq[i].to_double (), reason[i][0]);
2394 }
2395 
2396 /* Called when node is removed.  */
2397 
2398 static void
flatten_remove_node_hook(struct cgraph_node * node,void * data)2399 flatten_remove_node_hook (struct cgraph_node *node, void *data)
2400 {
2401   if (lookup_attribute ("flatten", DECL_ATTRIBUTES (node->decl)) == NULL)
2402     return;
2403 
2404   hash_set<struct cgraph_node *> *removed
2405     = (hash_set<struct cgraph_node *> *) data;
2406   removed->add (node);
2407 }
2408 
2409 /* Decide on the inlining.  We do so in the topological order to avoid
2410    expenses on updating data structures.  */
2411 
2412 static unsigned int
ipa_inline(void)2413 ipa_inline (void)
2414 {
2415   struct cgraph_node *node;
2416   int nnodes;
2417   struct cgraph_node **order;
2418   int i, j;
2419   int cold;
2420   bool remove_functions = false;
2421 
2422   order = XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);
2423 
2424   if (dump_file)
2425     ipa_dump_fn_summaries (dump_file);
2426 
2427   nnodes = ipa_reverse_postorder (order);
2428   spec_rem = profile_count::zero ();
2429 
2430   FOR_EACH_FUNCTION (node)
2431     {
2432       node->aux = 0;
2433 
2434       /* Recompute the default reasons for inlining because they may have
2435            changed during merging.  */
2436       if (in_lto_p)
2437           {
2438             for (cgraph_edge *e = node->callees; e; e = e->next_callee)
2439               {
2440                 gcc_assert (e->inline_failed);
2441                 initialize_inline_failed (e);
2442               }
2443             for (cgraph_edge *e = node->indirect_calls; e; e = e->next_callee)
2444               initialize_inline_failed (e);
2445           }
2446     }
2447 
2448   if (dump_file)
2449     fprintf (dump_file, "\nFlattening functions:\n");
2450 
2451   /* First shrink order array, so that it only contains nodes with
2452      flatten attribute.  */
2453   for (i = nnodes - 1, j = i; i >= 0; i--)
2454     {
2455       node = order[i];
2456       if (lookup_attribute ("flatten",
2457                                   DECL_ATTRIBUTES (node->decl)) != NULL)
2458           order[j--] = order[i];
2459     }
2460 
2461   /* After the above loop, order[j + 1] ... order[nnodes - 1] contain
2462      nodes with flatten attribute.  If there is more than one such
2463      node, we need to register a node removal hook, as flatten_function
2464      could remove other nodes with flatten attribute.  See PR82801.  */
2465   struct cgraph_node_hook_list *node_removal_hook_holder = NULL;
2466   hash_set<struct cgraph_node *> *flatten_removed_nodes = NULL;
2467   if (j < nnodes - 2)
2468     {
2469       flatten_removed_nodes = new hash_set<struct cgraph_node *>;
2470       node_removal_hook_holder
2471           = symtab->add_cgraph_removal_hook (&flatten_remove_node_hook,
2472                                                      flatten_removed_nodes);
2473     }
2474 
2475   /* In the first pass handle functions to be flattened.  Do this with
2476      a priority so none of our later choices will make this impossible.  */
2477   for (i = nnodes - 1; i > j; i--)
2478     {
2479       node = order[i];
2480       if (flatten_removed_nodes
2481             && flatten_removed_nodes->contains (node))
2482           continue;
2483 
2484       /* Handle nodes to be flattened.
2485            Ideally when processing callees we stop inlining at the
2486            entry of cycles, possibly cloning that entry point and
2487            try to flatten itself turning it into a self-recursive
2488            function.  */
2489       if (dump_file)
2490           fprintf (dump_file, "Flattening %s\n", node->name ());
2491       flatten_function (node, false);
2492     }
2493 
2494   if (j < nnodes - 2)
2495     {
2496       symtab->remove_cgraph_removal_hook (node_removal_hook_holder);
2497       delete flatten_removed_nodes;
2498     }
2499   free (order);
2500 
2501   if (dump_file)
2502     dump_overall_stats ();
2503 
2504   inline_small_functions ();
2505 
2506   gcc_assert (symtab->state == IPA_SSA);
2507   symtab->state = IPA_SSA_AFTER_INLINING;
2508   /* Do first after-inlining removal.  We want to remove all "stale" extern
2509      inline functions and virtual functions so we really know what is called
2510      once.  */
2511   symtab->remove_unreachable_nodes (dump_file);
2512 
2513   /* Inline functions with a property that after inlining into all callers the
2514      code size will shrink because the out-of-line copy is eliminated.
2515      We do this regardless on the callee size as long as function growth limits
2516      are met.  */
2517   if (dump_file)
2518     fprintf (dump_file,
2519                "\nDeciding on functions to be inlined into all callers and "
2520                "removing useless speculations:\n");
2521 
2522   /* Inlining one function called once has good chance of preventing
2523      inlining other function into the same callee.  Ideally we should
2524      work in priority order, but probably inlining hot functions first
2525      is good cut without the extra pain of maintaining the queue.
2526 
2527      ??? this is not really fitting the bill perfectly: inlining function
2528      into callee often leads to better optimization of callee due to
2529      increased context for optimization.
2530      For example if main() function calls a function that outputs help
2531      and then function that does the main optmization, we should inline
2532      the second with priority even if both calls are cold by themselves.
2533 
2534      We probably want to implement new predicate replacing our use of
2535      maybe_hot_edge interpreted as maybe_hot_edge || callee is known
2536      to be hot.  */
2537   for (cold = 0; cold <= 1; cold ++)
2538     {
2539       FOR_EACH_DEFINED_FUNCTION (node)
2540           {
2541             struct cgraph_edge *edge, *next;
2542             bool update=false;
2543 
2544             if (!opt_for_fn (node->decl, optimize)
2545                 || !opt_for_fn (node->decl, flag_inline_functions_called_once))
2546               continue;
2547 
2548             for (edge = node->callees; edge; edge = next)
2549               {
2550                 next = edge->next_callee;
2551                 if (edge->speculative && !speculation_useful_p (edge, false))
2552                     {
2553                       if (edge->count.ipa ().initialized_p ())
2554                         spec_rem += edge->count.ipa ();
2555                       edge->resolve_speculation ();
2556                       update = true;
2557                       remove_functions = true;
2558                     }
2559               }
2560             if (update)
2561               {
2562                 struct cgraph_node *where = node->global.inlined_to
2563                                                     ? node->global.inlined_to : node;
2564                 reset_edge_caches (where);
2565                 ipa_update_overall_fn_summary (where);
2566               }
2567             if (want_inline_function_to_all_callers_p (node, cold))
2568               {
2569                 int num_calls = 0;
2570                 node->call_for_symbol_and_aliases (sum_callers, &num_calls,
2571                                                              true);
2572                 while (node->call_for_symbol_and_aliases
2573                            (inline_to_all_callers, &num_calls, true))
2574                     ;
2575                 remove_functions = true;
2576               }
2577           }
2578     }
2579 
2580   /* Free ipa-prop structures if they are no longer needed.  */
2581   ipa_free_all_structures_after_iinln ();
2582 
2583   if (dump_file)
2584     {
2585       fprintf (dump_file,
2586                  "\nInlined %i calls, eliminated %i functions\n\n",
2587                  ncalls_inlined, nfunctions_inlined);
2588       dump_inline_stats ();
2589     }
2590 
2591   if (dump_file)
2592     ipa_dump_fn_summaries (dump_file);
2593   return remove_functions ? TODO_remove_functions : 0;
2594 }
2595 
2596 /* Inline always-inline function calls in NODE.  */
2597 
2598 static bool
inline_always_inline_functions(struct cgraph_node * node)2599 inline_always_inline_functions (struct cgraph_node *node)
2600 {
2601   struct cgraph_edge *e;
2602   bool inlined = false;
2603 
2604   for (e = node->callees; e; e = e->next_callee)
2605     {
2606       struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2607       if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl))
2608           continue;
2609 
2610       if (e->recursive_p ())
2611           {
2612             if (dump_file)
2613               fprintf (dump_file, "  Not inlining recursive call to %s.\n",
2614                          e->callee->name ());
2615             e->inline_failed = CIF_RECURSIVE_INLINING;
2616             continue;
2617           }
2618 
2619       if (!can_early_inline_edge_p (e))
2620           {
2621             /* Set inlined to true if the callee is marked "always_inline" but
2622                is not inlinable.  This will allow flagging an error later in
2623                expand_call_inline in tree-inline.c.  */
2624             if (lookup_attribute ("always_inline",
2625                                          DECL_ATTRIBUTES (callee->decl)) != NULL)
2626               inlined = true;
2627             continue;
2628           }
2629 
2630       if (dump_file)
2631           fprintf (dump_file, "  Inlining %s into %s (always_inline).\n",
2632                      xstrdup_for_dump (e->callee->name ()),
2633                      xstrdup_for_dump (e->caller->name ()));
2634       inline_call (e, true, NULL, NULL, false);
2635       inlined = true;
2636     }
2637   if (inlined)
2638     ipa_update_overall_fn_summary (node);
2639 
2640   return inlined;
2641 }
2642 
2643 /* Decide on the inlining.  We do so in the topological order to avoid
2644    expenses on updating data structures.  */
2645 
2646 static bool
early_inline_small_functions(struct cgraph_node * node)2647 early_inline_small_functions (struct cgraph_node *node)
2648 {
2649   struct cgraph_edge *e;
2650   bool inlined = false;
2651 
2652   for (e = node->callees; e; e = e->next_callee)
2653     {
2654       struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2655       if (!ipa_fn_summaries->get (callee)->inlinable
2656             || !e->inline_failed)
2657           continue;
2658 
2659       /* Do not consider functions not declared inline.  */
2660       if (!DECL_DECLARED_INLINE_P (callee->decl)
2661             && !opt_for_fn (node->decl, flag_inline_small_functions)
2662             && !opt_for_fn (node->decl, flag_inline_functions))
2663           continue;
2664 
2665       if (dump_file)
2666           fprintf (dump_file, "Considering inline candidate %s.\n",
2667                      callee->name ());
2668 
2669       if (!can_early_inline_edge_p (e))
2670           continue;
2671 
2672       if (e->recursive_p ())
2673           {
2674             if (dump_file)
2675               fprintf (dump_file, "  Not inlining: recursive call.\n");
2676             continue;
2677           }
2678 
2679       if (!want_early_inline_function_p (e))
2680           continue;
2681 
2682       if (dump_file)
2683           fprintf (dump_file, " Inlining %s into %s.\n",
2684                      xstrdup_for_dump (callee->name ()),
2685                      xstrdup_for_dump (e->caller->name ()));
2686       inline_call (e, true, NULL, NULL, false);
2687       inlined = true;
2688     }
2689 
2690   if (inlined)
2691     ipa_update_overall_fn_summary (node);
2692 
2693   return inlined;
2694 }
2695 
2696 unsigned int
early_inliner(function * fun)2697 early_inliner (function *fun)
2698 {
2699   struct cgraph_node *node = cgraph_node::get (current_function_decl);
2700   struct cgraph_edge *edge;
2701   unsigned int todo = 0;
2702   int iterations = 0;
2703   bool inlined = false;
2704 
2705   if (seen_error ())
2706     return 0;
2707 
2708   /* Do nothing if datastructures for ipa-inliner are already computed.  This
2709      happens when some pass decides to construct new function and
2710      cgraph_add_new_function calls lowering passes and early optimization on
2711      it.  This may confuse ourself when early inliner decide to inline call to
2712      function clone, because function clones don't have parameter list in
2713      ipa-prop matching their signature.  */
2714   if (ipa_node_params_sum)
2715     return 0;
2716 
2717   if (flag_checking)
2718     node->verify ();
2719   node->remove_all_references ();
2720 
2721   /* Rebuild this reference because it dosn't depend on
2722      function's body and it's required to pass cgraph_node
2723      verification.  */
2724   if (node->instrumented_version
2725       && !node->instrumentation_clone)
2726     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
2727 
2728   /* Even when not optimizing or not inlining inline always-inline
2729      functions.  */
2730   inlined = inline_always_inline_functions (node);
2731 
2732   if (!optimize
2733       || flag_no_inline
2734       || !flag_early_inlining
2735       /* Never inline regular functions into always-inline functions
2736            during incremental inlining.  This sucks as functions calling
2737            always inline functions will get less optimized, but at the
2738            same time inlining of functions calling always inline
2739            function into an always inline function might introduce
2740            cycles of edges to be always inlined in the callgraph.
2741 
2742            We might want to be smarter and just avoid this type of inlining.  */
2743       || (DECL_DISREGARD_INLINE_LIMITS (node->decl)
2744             && lookup_attribute ("always_inline",
2745                                      DECL_ATTRIBUTES (node->decl))))
2746     ;
2747   else if (lookup_attribute ("flatten",
2748                                    DECL_ATTRIBUTES (node->decl)) != NULL)
2749     {
2750       /* When the function is marked to be flattened, recursively inline
2751            all calls in it.  */
2752       if (dump_file)
2753           fprintf (dump_file,
2754                      "Flattening %s\n", node->name ());
2755       flatten_function (node, true);
2756       inlined = true;
2757     }
2758   else
2759     {
2760       /* If some always_inline functions was inlined, apply the changes.
2761            This way we will not account always inline into growth limits and
2762            moreover we will inline calls from always inlines that we skipped
2763            previously because of conditional above.  */
2764       if (inlined)
2765           {
2766             timevar_push (TV_INTEGRATION);
2767             todo |= optimize_inline_calls (current_function_decl);
2768             /* optimize_inline_calls call above might have introduced new
2769                statements that don't have inline parameters computed.  */
2770             for (edge = node->callees; edge; edge = edge->next_callee)
2771               {
2772                 struct ipa_call_summary *es = ipa_call_summaries->get (edge);
2773                 es->call_stmt_size
2774                     = estimate_num_insns (edge->call_stmt, &eni_size_weights);
2775                 es->call_stmt_time
2776                     = estimate_num_insns (edge->call_stmt, &eni_time_weights);
2777               }
2778             ipa_update_overall_fn_summary (node);
2779             inlined = false;
2780             timevar_pop (TV_INTEGRATION);
2781           }
2782       /* We iterate incremental inlining to get trivial cases of indirect
2783            inlining.  */
2784       while (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS)
2785                && early_inline_small_functions (node))
2786           {
2787             timevar_push (TV_INTEGRATION);
2788             todo |= optimize_inline_calls (current_function_decl);
2789 
2790             /* Technically we ought to recompute inline parameters so the new
2791                iteration of early inliner works as expected.  We however have
2792                values approximately right and thus we only need to update edge
2793                info that might be cleared out for newly discovered edges.  */
2794             for (edge = node->callees; edge; edge = edge->next_callee)
2795               {
2796                 /* We have no summary for new bound store calls yet.  */
2797                 struct ipa_call_summary *es = ipa_call_summaries->get (edge);
2798                 es->call_stmt_size
2799                     = estimate_num_insns (edge->call_stmt, &eni_size_weights);
2800                 es->call_stmt_time
2801                     = estimate_num_insns (edge->call_stmt, &eni_time_weights);
2802 
2803                 if (edge->callee->decl
2804                       && !gimple_check_call_matching_types (
2805                           edge->call_stmt, edge->callee->decl, false))
2806                     {
2807                       edge->inline_failed = CIF_MISMATCHED_ARGUMENTS;
2808                       edge->call_stmt_cannot_inline_p = true;
2809                     }
2810               }
2811             if (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS) - 1)
2812               ipa_update_overall_fn_summary (node);
2813             timevar_pop (TV_INTEGRATION);
2814             iterations++;
2815             inlined = false;
2816           }
2817       if (dump_file)
2818           fprintf (dump_file, "Iterations: %i\n", iterations);
2819     }
2820 
2821   if (inlined)
2822     {
2823       timevar_push (TV_INTEGRATION);
2824       todo |= optimize_inline_calls (current_function_decl);
2825       timevar_pop (TV_INTEGRATION);
2826     }
2827 
2828   fun->always_inline_functions_inlined = true;
2829 
2830   return todo;
2831 }
2832 
2833 /* Do inlining of small functions.  Doing so early helps profiling and other
2834    passes to be somewhat more effective and avoids some code duplication in
2835    later real inlining pass for testcases with very many function calls.  */
2836 
2837 namespace {
2838 
2839 const pass_data pass_data_early_inline =
2840 {
2841   GIMPLE_PASS, /* type */
2842   "einline", /* name */
2843   OPTGROUP_INLINE, /* optinfo_flags */
2844   TV_EARLY_INLINING, /* tv_id */
2845   PROP_ssa, /* properties_required */
2846   0, /* properties_provided */
2847   0, /* properties_destroyed */
2848   0, /* todo_flags_start */
2849   0, /* todo_flags_finish */
2850 };
2851 
2852 class pass_early_inline : public gimple_opt_pass
2853 {
2854 public:
pass_early_inline(gcc::context * ctxt)2855   pass_early_inline (gcc::context *ctxt)
2856     : gimple_opt_pass (pass_data_early_inline, ctxt)
2857   {}
2858 
2859   /* opt_pass methods: */
2860   virtual unsigned int execute (function *);
2861 
2862 }; // class pass_early_inline
2863 
2864 unsigned int
execute(function * fun)2865 pass_early_inline::execute (function *fun)
2866 {
2867   return early_inliner (fun);
2868 }
2869 
2870 } // anon namespace
2871 
2872 gimple_opt_pass *
make_pass_early_inline(gcc::context * ctxt)2873 make_pass_early_inline (gcc::context *ctxt)
2874 {
2875   return new pass_early_inline (ctxt);
2876 }
2877 
2878 namespace {
2879 
2880 const pass_data pass_data_ipa_inline =
2881 {
2882   IPA_PASS, /* type */
2883   "inline", /* name */
2884   OPTGROUP_INLINE, /* optinfo_flags */
2885   TV_IPA_INLINING, /* tv_id */
2886   0, /* properties_required */
2887   0, /* properties_provided */
2888   0, /* properties_destroyed */
2889   0, /* todo_flags_start */
2890   ( TODO_dump_symtab ), /* todo_flags_finish */
2891 };
2892 
2893 class pass_ipa_inline : public ipa_opt_pass_d
2894 {
2895 public:
pass_ipa_inline(gcc::context * ctxt)2896   pass_ipa_inline (gcc::context *ctxt)
2897     : ipa_opt_pass_d (pass_data_ipa_inline, ctxt,
2898                           NULL, /* generate_summary */
2899                           NULL, /* write_summary */
2900                           NULL, /* read_summary */
2901                           NULL, /* write_optimization_summary */
2902                           NULL, /* read_optimization_summary */
2903                           NULL, /* stmt_fixup */
2904                           0, /* function_transform_todo_flags_start */
2905                           inline_transform, /* function_transform */
2906                           NULL) /* variable_transform */
2907   {}
2908 
2909   /* opt_pass methods: */
execute(function *)2910   virtual unsigned int execute (function *) { return ipa_inline (); }
2911 
2912 }; // class pass_ipa_inline
2913 
2914 } // anon namespace
2915 
2916 ipa_opt_pass_d *
make_pass_ipa_inline(gcc::context * ctxt)2917 make_pass_ipa_inline (gcc::context *ctxt)
2918 {
2919   return new pass_ipa_inline (ctxt);
2920 }
2921