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llvmjit_inline.cpp
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1 /*-------------------------------------------------------------------------
2  *
3  * llvmjit_inline.cpp
4  * Cross module inlining suitable for postgres' JIT
5  *
6  * The inliner iterates over external functions referenced from the passed
7  * module and attempts to inline those. It does so by utilizing pre-built
8  * indexes over both postgres core code and extension modules. When a match
9  * for an external function is found - not guaranteed! - the index will then
10  * be used to judge their instruction count / inline worthiness. After doing
11  * so for all external functions, all the referenced functions (and
12  * prerequisites) will be imported.
13  *
14  * Copyright (c) 2016-2019, PostgreSQL Global Development Group
15  *
16  * IDENTIFICATION
17  * src/backend/lib/llvmjit/llvmjit_inline.cpp
18  *
19  *-------------------------------------------------------------------------
20  */
21 
22 extern "C"
23 {
24 #include "postgres.h"
25 }
26 
27 #include "jit/llvmjit.h"
28 
29 extern "C"
30 {
31 #include <fcntl.h>
32 #include <sys/mman.h>
33 #include <sys/stat.h>
34 #include <sys/types.h>
35 #include <unistd.h>
36 
37 #include "common/string.h"
38 #include "miscadmin.h"
39 #include "storage/fd.h"
40 }
41 
42 #include <llvm-c/Core.h>
43 #include <llvm-c/BitReader.h>
44 
45 /* Avoid macro clash with LLVM's C++ headers */
46 #undef Min
47 
48 #include <llvm/ADT/SetVector.h>
49 #include <llvm/ADT/StringSet.h>
50 #include <llvm/ADT/StringMap.h>
51 #include <llvm/Analysis/ModuleSummaryAnalysis.h>
52 #if LLVM_VERSION_MAJOR > 3
53 #include <llvm/Bitcode/BitcodeReader.h>
54 #else
55 #include <llvm/Bitcode/ReaderWriter.h>
56 #include <llvm/Support/Error.h>
57 #endif
58 #include <llvm/IR/Attributes.h>
59 #include <llvm/IR/CallSite.h>
60 #include <llvm/IR/DebugInfo.h>
61 #include <llvm/IR/IntrinsicInst.h>
62 #include <llvm/IR/IRBuilder.h>
63 #include <llvm/IR/ModuleSummaryIndex.h>
64 #include <llvm/Linker/IRMover.h>
65 #include <llvm/Support/ManagedStatic.h>
66 
67 
68 /*
69  * Type used to represent modules InlineWorkListItem's subject is searched for
70  * in.
71  */
72 typedef llvm::SmallVector<llvm::ModuleSummaryIndex *, 2> InlineSearchPath;
73 
74 /*
75  * Item in queue of to-be-checked symbols and corresponding queue.
76  */
77 typedef struct InlineWorkListItem
78 {
79  llvm::StringRef symbolName;
80  llvm::SmallVector<llvm::ModuleSummaryIndex *, 2> searchpath;
82 typedef llvm::SmallVector<InlineWorkListItem, 128> InlineWorkList;
83 
84 /*
85  * Information about symbols processed during inlining. Used to prevent
86  * repeated searches and provide additional information.
87  */
88 typedef struct FunctionInlineState
89 {
90  int costLimit;
91  bool processed;
92  bool inlined;
95 typedef llvm::StringMap<FunctionInlineState> FunctionInlineStates;
96 
97 /*
98  * Map of modules that should be inlined, with a list of the to-be inlined
99  * symbols.
100  */
101 typedef llvm::StringMap<llvm::StringSet<> > ImportMapTy;
102 
103 
104 const float inline_cost_decay_factor = 0.5;
105 const int inline_initial_cost = 150;
106 
107 /*
108  * These are managed statics so LLVM knows to deallocate them during an
109  * LLVMShutdown(), rather than after (which'd cause crashes).
110  */
111 typedef llvm::StringMap<std::unique_ptr<llvm::Module> > ModuleCache;
112 llvm::ManagedStatic<ModuleCache> module_cache;
113 typedef llvm::StringMap<std::unique_ptr<llvm::ModuleSummaryIndex> > SummaryCache;
114 llvm::ManagedStatic<SummaryCache> summary_cache;
115 
116 
117 static std::unique_ptr<ImportMapTy> llvm_build_inline_plan(llvm::Module *mod);
118 static void llvm_execute_inline_plan(llvm::Module *mod,
119  ImportMapTy *globalsToInline);
120 
121 static llvm::Module* load_module_cached(llvm::StringRef modPath);
122 static std::unique_ptr<llvm::Module> load_module(llvm::StringRef Identifier);
123 static std::unique_ptr<llvm::ModuleSummaryIndex> llvm_load_summary(llvm::StringRef path);
124 
125 
126 static llvm::Function* create_redirection_function(std::unique_ptr<llvm::Module> &importMod,
127  llvm::Function *F,
128  llvm::StringRef Name);
129 
130 static bool function_inlinable(llvm::Function &F,
131  int threshold,
132  FunctionInlineStates &functionState,
133  InlineWorkList &worklist,
135  llvm::SmallPtrSet<const llvm::Function *, 8> &visitedFunctions,
136  int &running_instcount,
137  llvm::StringSet<> &importVars);
138 static void function_references(llvm::Function &F,
139  int &running_instcount,
140  llvm::SmallPtrSet<llvm::GlobalVariable *, 8> &referencedVars,
141  llvm::SmallPtrSet<llvm::Function *, 8> &referencedFunctions);
142 
143 static void add_module_to_inline_search_path(InlineSearchPath& path, llvm::StringRef modpath);
144 static llvm::SmallVector<llvm::GlobalValueSummary *, 1>
145 summaries_for_guid(const InlineSearchPath& path, llvm::GlobalValue::GUID guid);
146 
147 /* verbose debugging for inliner development */
148 /* #define INLINE_DEBUG */
149 #ifdef INLINE_DEBUG
150 #define ilog elog
151 #else
152 #define ilog(...) (void) 0
153 #endif
154 
155 /*
156  * Perform inlining of external function references in M based on a simple
157  * cost based analysis.
158  */
159 void
160 llvm_inline(LLVMModuleRef M)
161 {
162  llvm::Module *mod = llvm::unwrap(M);
163 
164  std::unique_ptr<ImportMapTy> globalsToInline = llvm_build_inline_plan(mod);
165  if (!globalsToInline)
166  return;
167  llvm_execute_inline_plan(mod, globalsToInline.get());
168 }
169 
170 /*
171  * Build information necessary for inlining external function references in
172  * mod.
173  */
174 static std::unique_ptr<ImportMapTy>
175 llvm_build_inline_plan(llvm::Module *mod)
176 {
177  std::unique_ptr<ImportMapTy> globalsToInline = llvm::make_unique<ImportMapTy>();
178  FunctionInlineStates functionStates;
179  InlineWorkList worklist;
180 
181  InlineSearchPath defaultSearchPath;
182 
183  /* attempt to add module to search path */
184  add_module_to_inline_search_path(defaultSearchPath, "$libdir/postgres");
185  /* if postgres isn't available, no point continuing */
186  if (defaultSearchPath.empty())
187  return nullptr;
188 
189  /*
190  * Start inlining with current references to external functions by putting
191  * them on the inlining worklist. If, during inlining of those, new extern
192  * functions need to be inlined, they'll also be put there, with a lower
193  * priority.
194  */
195  for (const llvm::Function &funcDecl : mod->functions())
196  {
197  InlineWorkListItem item = {};
198  FunctionInlineState inlineState = {};
199 
200  /* already has a definition */
201  if (!funcDecl.isDeclaration())
202  continue;
203 
204  /* llvm provides implementation */
205  if (funcDecl.isIntrinsic())
206  continue;
207 
208  item.symbolName = funcDecl.getName();
209  item.searchpath = defaultSearchPath;
210  worklist.push_back(item);
211  inlineState.costLimit = inline_initial_cost;
212  inlineState.processed = false;
213  inlineState.inlined = false;
214  inlineState.allowReconsidering = false;
215  functionStates[funcDecl.getName()] = inlineState;
216  }
217 
218  /*
219  * Iterate over pending worklist items, look them up in index, check
220  * whether they should be inlined.
221  */
222  while (!worklist.empty())
223  {
224  InlineWorkListItem item = worklist.pop_back_val();
225  llvm::StringRef symbolName = item.symbolName;
226  char *cmodname;
227  char *cfuncname;
228  FunctionInlineState &inlineState = functionStates[symbolName];
229  llvm::GlobalValue::GUID funcGUID;
230 
231  llvm_split_symbol_name(symbolName.data(), &cmodname, &cfuncname);
232 
233  funcGUID = llvm::GlobalValue::getGUID(cfuncname);
234 
235  /* already processed */
236  if (inlineState.processed)
237  continue;
238 
239 
240  if (cmodname)
242 
243  /*
244  * Iterate over all known definitions of function, via the index. Then
245  * look up module(s), check if function actually is defined (there
246  * could be hash conflicts).
247  */
248  for (const auto &gvs : summaries_for_guid(item.searchpath, funcGUID))
249  {
250  const llvm::FunctionSummary *fs;
251  llvm::StringRef modPath = gvs->modulePath();
252  llvm::Module *defMod;
253  llvm::Function *funcDef;
254 
255  fs = llvm::cast<llvm::FunctionSummary>(gvs);
256 
257 #if LLVM_VERSION_MAJOR > 3
258  if (gvs->notEligibleToImport())
259  {
260  ilog(DEBUG1, "ineligibile to import %s due to summary",
261  symbolName.data());
262  continue;
263  }
264 #endif
265 
266  if ((int) fs->instCount() > inlineState.costLimit)
267  {
268  ilog(DEBUG1, "ineligibile to import %s due to early threshold: %u vs %u",
269  symbolName.data(), fs->instCount(), inlineState.costLimit);
270  inlineState.allowReconsidering = true;
271  continue;
272  }
273 
274  defMod = load_module_cached(modPath);
275  if (defMod->materializeMetadata())
276  elog(FATAL, "failed to materialize metadata");
277 
278  funcDef = defMod->getFunction(cfuncname);
279 
280  /*
281  * This can happen e.g. in case of a hash collision of the
282  * function's name.
283  */
284  if (!funcDef)
285  continue;
286 
287  if (funcDef->materialize())
288  elog(FATAL, "failed to materialize metadata");
289 
290  Assert(!funcDef->isDeclaration());
291  Assert(funcDef->hasExternalLinkage());
292 
293  llvm::StringSet<> importVars;
294  llvm::SmallPtrSet<const llvm::Function *, 8> visitedFunctions;
295  int running_instcount = 0;
296 
297  /*
298  * Check whether function, and objects it depends on, are
299  * inlinable.
300  */
301  if (function_inlinable(*funcDef,
302  inlineState.costLimit,
303  functionStates,
304  worklist,
305  item.searchpath,
306  visitedFunctions,
307  running_instcount,
308  importVars))
309  {
310  /*
311  * Check whether function and all its dependencies are too
312  * big. Dependencies already counted for other functions that
313  * will get inlined are not counted again. While this make
314  * things somewhat order dependent, I can't quite see a point
315  * in a different behaviour.
316  */
317  if (running_instcount > inlineState.costLimit)
318  {
319  ilog(DEBUG1, "skipping inlining of %s due to late threshold %d vs %d",
320  symbolName.data(), running_instcount, inlineState.costLimit);
321  inlineState.allowReconsidering = true;
322  continue;
323  }
324 
325  ilog(DEBUG1, "inline top function %s total_instcount: %d, partial: %d",
326  symbolName.data(), running_instcount, fs->instCount());
327 
328  /* import referenced function itself */
329  importVars.insert(symbolName);
330 
331  {
332  llvm::StringSet<> &modGlobalsToInline = (*globalsToInline)[modPath];
333  for (auto& importVar : importVars)
334  modGlobalsToInline.insert(importVar.first());
335  Assert(modGlobalsToInline.size() > 0);
336  }
337 
338  /* mark function as inlined */
339  inlineState.inlined = true;
340 
341  /*
342  * Found definition to inline, don't look for further
343  * potential definitions.
344  */
345  break;
346  }
347  else
348  {
349  ilog(DEBUG1, "had to skip inlining %s",
350  symbolName.data());
351 
352  /* It's possible there's another definition that's inlinable. */
353  }
354  }
355 
356  /*
357  * Signal that we're done with symbol, whether successful (inlined =
358  * true above) or not.
359  */
360  inlineState.processed = true;
361  }
362 
363  return globalsToInline;
364 }
365 
366 /*
367  * Perform the actual inlining of external functions (and their dependencies)
368  * into mod.
369  */
370 static void
371 llvm_execute_inline_plan(llvm::Module *mod, ImportMapTy *globalsToInline)
372 {
373  llvm::IRMover Mover(*mod);
374 
375  for (const auto& toInline : *globalsToInline)
376  {
377  const llvm::StringRef& modPath = toInline.first();
378  const llvm::StringSet<>& modGlobalsToInline = toInline.second;
379  llvm::SetVector<llvm::GlobalValue *> GlobalsToImport;
380 
381  Assert(module_cache->count(modPath));
382  std::unique_ptr<llvm::Module> importMod(std::move((*module_cache)[modPath]));
383  module_cache->erase(modPath);
384 
385  if (modGlobalsToInline.empty())
386  continue;
387 
388  for (auto &glob: modGlobalsToInline)
389  {
390  llvm::StringRef SymbolName = glob.first();
391  char *modname;
392  char *funcname;
393 
394  llvm_split_symbol_name(SymbolName.data(), &modname, &funcname);
395 
396  llvm::GlobalValue *valueToImport = importMod->getNamedValue(funcname);
397 
398  if (!valueToImport)
399  elog(FATAL, "didn't refind value %s to import", SymbolName.data());
400 
401  /*
402  * For functions (global vars are only inlined if already static),
403  * mark imported variables as being clones from other
404  * functions. That a) avoids symbol conflicts b) allows the
405  * optimizer to perform inlining.
406  */
407  if (llvm::isa<llvm::Function>(valueToImport))
408  {
409  llvm::Function *F = llvm::dyn_cast<llvm::Function>(valueToImport);
410  typedef llvm::GlobalValue::LinkageTypes LinkageTypes;
411 
412  /*
413  * Per-function info isn't necessarily stripped yet, as the
414  * module is lazy-loaded when stripped above.
415  */
416  llvm::stripDebugInfo(*F);
417 
418  /*
419  * If the to-be-imported function is one referenced including
420  * its module name, create a tiny inline function that just
421  * forwards the call. One might think a GlobalAlias would do
422  * the trick, but a) IRMover doesn't override a declaration
423  * with an alias pointing to a definition (instead renaming
424  * it), b) Aliases can't be AvailableExternally.
425  */
426  if (modname)
427  {
428  llvm::Function *AF;
429 
430  AF = create_redirection_function(importMod, F, SymbolName);
431 
432  GlobalsToImport.insert(AF);
433  llvm::stripDebugInfo(*AF);
434  }
435 
436  if (valueToImport->hasExternalLinkage())
437  {
438  valueToImport->setLinkage(LinkageTypes::AvailableExternallyLinkage);
439  }
440  }
441 
442  GlobalsToImport.insert(valueToImport);
443  ilog(DEBUG1, "performing import of %s %s",
444  modPath.data(), SymbolName.data());
445 
446  }
447 
448 #if LLVM_VERSION_MAJOR > 4
449 #define IRMOVE_PARAMS , /*IsPerformingImport=*/false
450 #elif LLVM_VERSION_MAJOR > 3
451 #define IRMOVE_PARAMS , /*LinkModuleInlineAsm=*/false, /*IsPerformingImport=*/false
452 #else
453 #define IRMOVE_PARAMS
454 #endif
455  if (Mover.move(std::move(importMod), GlobalsToImport.getArrayRef(),
456  [](llvm::GlobalValue &, llvm::IRMover::ValueAdder) {}
457  IRMOVE_PARAMS))
458  elog(FATAL, "function import failed with linker error");
459  }
460 }
461 
462 /*
463  * Return a module identified by modPath, caching it in memory.
464  *
465  * Note that such a module may *not* be modified without copying, otherwise
466  * the cache state would get corrupted.
467  */
468 static llvm::Module*
469 load_module_cached(llvm::StringRef modPath)
470 {
471  auto it = module_cache->find(modPath);
472  if (it == module_cache->end())
473  {
474  it = module_cache->insert(
475  std::make_pair(modPath, load_module(modPath))).first;
476  }
477 
478  return it->second.get();
479 }
480 
481 static std::unique_ptr<llvm::Module>
482 load_module(llvm::StringRef Identifier)
483 {
484  LLVMMemoryBufferRef buf;
485  LLVMModuleRef mod;
486  char path[MAXPGPATH];
487  char *msg;
488 
489  snprintf(path, MAXPGPATH,"%s/bitcode/%s", pkglib_path, Identifier.data());
490 
491  if (LLVMCreateMemoryBufferWithContentsOfFile(path, &buf, &msg))
492  elog(FATAL, "failed to open bitcode file \"%s\": %s",
493  path, msg);
494  if (LLVMGetBitcodeModuleInContext2(LLVMGetGlobalContext(), buf, &mod))
495  elog(FATAL, "failed to parse bitcode in file \"%s\"", path);
496 
497  /*
498  * Currently there's no use in more detailed debug info for JITed
499  * code. Until that changes, not much point in wasting memory and cycles
500  * on processing debuginfo.
501  */
502  llvm::StripDebugInfo(*llvm::unwrap(mod));
503 
504  return std::unique_ptr<llvm::Module>(llvm::unwrap(mod));
505 }
506 
507 /*
508  * Compute list of referenced variables, functions and the instruction count
509  * for a function.
510  */
511 static void
512 function_references(llvm::Function &F,
513  int &running_instcount,
514  llvm::SmallPtrSet<llvm::GlobalVariable *, 8> &referencedVars,
515  llvm::SmallPtrSet<llvm::Function *, 8> &referencedFunctions)
516 {
517  llvm::SmallPtrSet<const llvm::User *, 32> Visited;
518 
519  for (llvm::BasicBlock &BB : F)
520  {
521  for (llvm::Instruction &I : BB)
522  {
523  if (llvm::isa<llvm::DbgInfoIntrinsic>(I))
524  continue;
525 
526  llvm::SmallVector<llvm::User *, 8> Worklist;
527  Worklist.push_back(&I);
528 
529  running_instcount++;
530 
531  while (!Worklist.empty()) {
532  llvm::User *U = Worklist.pop_back_val();
533 
534  /* visited before */
535  if (!Visited.insert(U).second)
536  continue;
537 
538  for (auto &OI : U->operands()) {
539  llvm::User *Operand = llvm::dyn_cast<llvm::User>(OI);
540  if (!Operand)
541  continue;
542  if (llvm::isa<llvm::BlockAddress>(Operand))
543  continue;
544  if (auto *GV = llvm::dyn_cast<llvm::GlobalVariable>(Operand)) {
545  referencedVars.insert(GV);
546  if (GV->hasInitializer())
547  Worklist.push_back(GV->getInitializer());
548  continue;
549  }
550  if (auto *CF = llvm::dyn_cast<llvm::Function>(Operand)) {
551  referencedFunctions.insert(CF);
552  continue;
553  }
554  Worklist.push_back(Operand);
555  }
556  }
557  }
558  }
559 }
560 
561 /*
562  * Check whether function F is inlinable and, if so, what globals need to be
563  * imported.
564  *
565  * References to external functions from, potentially recursively, inlined
566  * functions are added to the passed in worklist.
567  */
568 static bool
569 function_inlinable(llvm::Function &F,
570  int threshold,
571  FunctionInlineStates &functionStates,
572  InlineWorkList &worklist,
574  llvm::SmallPtrSet<const llvm::Function *, 8> &visitedFunctions,
575  int &running_instcount,
576  llvm::StringSet<> &importVars)
577 {
578  int subThreshold = threshold * inline_cost_decay_factor;
579  llvm::SmallPtrSet<llvm::GlobalVariable *, 8> referencedVars;
580  llvm::SmallPtrSet<llvm::Function *, 8> referencedFunctions;
581 
582  /* can't rely on what may be inlined */
583  if (F.isInterposable())
584  return false;
585 
586  /*
587  * Can't rely on function being present. Alternatively we could create a
588  * static version of these functions?
589  */
590  if (F.hasAvailableExternallyLinkage())
591  return false;
592 
593  ilog(DEBUG1, "checking inlinability of %s", F.getName().data());
594 
595  if (F.materialize())
596  elog(FATAL, "failed to materialize metadata");
597 
598  if (F.getAttributes().hasFnAttribute(llvm::Attribute::NoInline))
599  {
600  ilog(DEBUG1, "ineligibile to import %s due to noinline",
601  F.getName().data());
602  return false;
603  }
604 
605  function_references(F, running_instcount, referencedVars, referencedFunctions);
606 
607  for (llvm::GlobalVariable* rv: referencedVars)
608  {
609  if (rv->materialize())
610  elog(FATAL, "failed to materialize metadata");
611 
612  /*
613  * Never want to inline externally visible vars, cheap enough to
614  * reference.
615  */
616  if (rv->hasExternalLinkage() || rv->hasAvailableExternallyLinkage())
617  continue;
618 
619  /*
620  * If variable is file-local, we need to inline it, to be able to
621  * inline the function itself. Can't do that if the variable can be
622  * modified, because they'd obviously get out of sync.
623  *
624  * XXX: Currently not a problem, but there'd be problems with
625  * nontrivial initializers if they were allowed for postgres.
626  */
627  if (!rv->isConstant())
628  {
629  ilog(DEBUG1, "cannot inline %s due to uncloneable variable %s",
630  F.getName().data(), rv->getName().data());
631  return false;
632  }
633 
634  ilog(DEBUG1, "memorizing global var %s linkage %d for inlining",
635  rv->getName().data(), (int)rv->getLinkage());
636 
637  importVars.insert(rv->getName());
638  /* small cost attributed to each cloned global */
639  running_instcount += 5;
640  }
641 
642  visitedFunctions.insert(&F);
643 
644  /*
645  * Check referenced functions. Check whether used static ones are
646  * inlinable, and remember external ones for inlining.
647  */
648  for (llvm::Function* referencedFunction: referencedFunctions)
649  {
650  llvm::StringSet<> recImportVars;
651 
652  if (referencedFunction->materialize())
653  elog(FATAL, "failed to materialize metadata");
654 
655  if (referencedFunction->isIntrinsic())
656  continue;
657 
658  /* if already visited skip, otherwise remember */
659  if (!visitedFunctions.insert(referencedFunction).second)
660  continue;
661 
662  /*
663  * We don't inline external functions directly here, instead we put
664  * them on the worklist if appropriate and check them from
665  * llvm_build_inline_plan().
666  */
667  if (referencedFunction->hasExternalLinkage())
668  {
669  llvm::StringRef funcName = referencedFunction->getName();
670 
671  /*
672  * Don't bother checking for inlining if remaining cost budget is
673  * very small.
674  */
675  if (subThreshold < 5)
676  continue;
677 
678  auto it = functionStates.find(funcName);
679  if (it == functionStates.end())
680  {
681  FunctionInlineState inlineState;
682 
683  inlineState.costLimit = subThreshold;
684  inlineState.processed = false;
685  inlineState.inlined = false;
686  inlineState.allowReconsidering = false;
687 
688  functionStates[funcName] = inlineState;
689  worklist.push_back({funcName, searchpath});
690 
691  ilog(DEBUG1,
692  "considering extern function %s at %d for inlining",
693  funcName.data(), subThreshold);
694  }
695  else if (!it->second.inlined &&
696  (!it->second.processed || it->second.allowReconsidering) &&
697  it->second.costLimit < subThreshold)
698  {
699  /*
700  * Update inlining threshold if higher. Need to re-queue
701  * to be processed if already processed with lower
702  * threshold.
703  */
704  if (it->second.processed)
705  {
706  ilog(DEBUG1,
707  "reconsidering extern function %s at %d for inlining, increasing from %d",
708  funcName.data(), subThreshold, it->second.costLimit);
709 
710  it->second.processed = false;
711  it->second.allowReconsidering = false;
712  worklist.push_back({funcName, searchpath});
713  }
714  it->second.costLimit = subThreshold;
715  }
716  continue;
717  }
718 
719  /* can't rely on what may be inlined */
720  if (referencedFunction->isInterposable())
721  return false;
722 
723  if (!function_inlinable(*referencedFunction,
724  subThreshold,
725  functionStates,
726  worklist,
727  searchpath,
728  visitedFunctions,
729  running_instcount,
730  recImportVars))
731  {
732  ilog(DEBUG1,
733  "cannot inline %s due to required function %s not being inlinable",
734  F.getName().data(), referencedFunction->getName().data());
735  return false;
736  }
737 
738  /* import referenced function itself */
739  importVars.insert(referencedFunction->getName());
740 
741  /* import referenced function and its dependants */
742  for (auto& recImportVar : recImportVars)
743  importVars.insert(recImportVar.first());
744  }
745 
746  return true;
747 }
748 
749 /*
750  * Attempt to load module summary located at path. Return empty pointer when
751  * loading fails.
752  */
753 static std::unique_ptr<llvm::ModuleSummaryIndex>
754 llvm_load_summary(llvm::StringRef path)
755 {
756  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer> > MBOrErr =
757  llvm::MemoryBuffer::getFile(path);
758 
759  if (std::error_code EC = MBOrErr.getError())
760  {
761  ilog(DEBUG1, "failed to open %s: %s", path.data(),
762  EC.message().c_str());
763  }
764  else
765  {
766  llvm::MemoryBufferRef ref(*MBOrErr.get().get());
767 
768 #if LLVM_VERSION_MAJOR > 3
769  llvm::Expected<std::unique_ptr<llvm::ModuleSummaryIndex> > IndexOrErr =
770  llvm::getModuleSummaryIndex(ref);
771  if (IndexOrErr)
772  return std::move(IndexOrErr.get());
773  elog(FATAL, "failed to load summary \"%s\": %s",
774  path.data(),
775  toString(IndexOrErr.takeError()).c_str());
776 #else
777  llvm::ErrorOr<std::unique_ptr<llvm::ModuleSummaryIndex> > IndexOrErr =
778  llvm::getModuleSummaryIndex(ref, [](const llvm::DiagnosticInfo &) {});
779  if (IndexOrErr)
780  return std::move(IndexOrErr.get());
781  elog(FATAL, "failed to load summary \"%s\": %s",
782  path.data(),
783  IndexOrErr.getError().message().c_str());
784 #endif
785  }
786  return nullptr;
787 }
788 
789 /*
790  * Attempt to add modpath to the search path.
791  */
792 static void
794 {
795  /* only extension in libdir are candidates for inlining for now */
796  if (!modpath.startswith("$libdir/"))
797  return;
798 
799  /* if there's no match, attempt to load */
800  auto it = summary_cache->find(modpath);
801  if (it == summary_cache->end())
802  {
803  std::string path(modpath);
804  path = path.replace(0, strlen("$libdir"), std::string(pkglib_path) + "/bitcode");
805  path += ".index.bc";
806  (*summary_cache)[modpath] = llvm_load_summary(path);
807  it = summary_cache->find(modpath);
808  }
809 
810  Assert(it != summary_cache->end());
811 
812  /* if the entry isn't NULL, it's validly loaded */
813  if (it->second)
814  searchpath.push_back(it->second.get());
815 }
816 
817 /*
818  * Search for all references for functions hashing to guid in the search path,
819  * and return them in search path order.
820  */
821 static llvm::SmallVector<llvm::GlobalValueSummary *, 1>
822 summaries_for_guid(const InlineSearchPath& path, llvm::GlobalValue::GUID guid)
823 {
824  llvm::SmallVector<llvm::GlobalValueSummary *, 1> matches;
825 
826  for (auto index : path)
827  {
828 #if LLVM_VERSION_MAJOR > 4
829  llvm::ValueInfo funcVI = index->getValueInfo(guid);
830 
831  /* if index doesn't know function, we don't have a body, continue */
832  if (funcVI)
833  for (auto &gv : funcVI.getSummaryList())
834  matches.push_back(gv.get());
835 #else
836  const llvm::const_gvsummary_iterator &I =
837  index->findGlobalValueSummaryList(guid);
838  if (I != index->end())
839  {
840  for (auto &gv : I->second)
841  matches.push_back(gv.get());
842  }
843 #endif
844  }
845 
846  return matches;
847 }
848 
849 /*
850  * Create inline wrapper with the name Name, redirecting the call to F.
851  */
852 static llvm::Function*
853 create_redirection_function(std::unique_ptr<llvm::Module> &importMod,
854  llvm::Function *F,
855  llvm::StringRef Name)
856 {
857  typedef llvm::GlobalValue::LinkageTypes LinkageTypes;
858 
859  llvm::LLVMContext &Context = F->getContext();
860  llvm::IRBuilder<> Builder(Context);
861  llvm::Function *AF;
862  llvm::BasicBlock *BB;
863  llvm::CallInst *fwdcall;
864  llvm::Attribute inlineAttribute;
865 
866  AF = llvm::Function::Create(F->getFunctionType(),
867  LinkageTypes::AvailableExternallyLinkage,
868  Name, importMod.get());
869  BB = llvm::BasicBlock::Create(Context, "entry", AF);
870 
871  Builder.SetInsertPoint(BB);
872  fwdcall = Builder.CreateCall(F, &*AF->arg_begin());
873  inlineAttribute = llvm::Attribute::get(Context,
874  llvm::Attribute::AlwaysInline);
875  fwdcall->addAttribute(~0U, inlineAttribute);
876  Builder.CreateRet(fwdcall);
877 
878  return AF;
879 }
llvm::StringMap< FunctionInlineState > FunctionInlineStates
static bool function_inlinable(llvm::Function &F, int threshold, FunctionInlineStates &functionState, InlineWorkList &worklist, InlineSearchPath &searchpath, llvm::SmallPtrSet< const llvm::Function *, 8 > &visitedFunctions, int &running_instcount, llvm::StringSet<> &importVars)
llvm::StringMap< llvm::StringSet<> > ImportMapTy
llvm::SmallVector< llvm::ModuleSummaryIndex *, 2 > searchpath
#define DEBUG1
Definition: elog.h:25
#define F(x)
Definition: blf.c:249
#define IRMOVE_PARAMS
llvm::ManagedStatic< SummaryCache > summary_cache
llvm::StringRef symbolName
const int inline_initial_cost
static llvm::Module * load_module_cached(llvm::StringRef modPath)
Definition: type.h:89
static void function_references(llvm::Function &F, int &running_instcount, llvm::SmallPtrSet< llvm::GlobalVariable *, 8 > &referencedVars, llvm::SmallPtrSet< llvm::Function *, 8 > &referencedFunctions)
void llvm_split_symbol_name(const char *name, char **modname, char **funcname)
Definition: llvmjit.c:850
static llvm::SmallVector< llvm::GlobalValueSummary *, 1 > summaries_for_guid(const InlineSearchPath &path, llvm::GlobalValue::GUID guid)
#define FATAL
Definition: elog.h:52
#define MAXPGPATH
Definition: c.h:603
static char * buf
Definition: pg_test_fsync.c:68
llvm::StringMap< std::unique_ptr< llvm::ModuleSummaryIndex > > SummaryCache
char string[11]
Definition: preproc-type.c:46
#define I(X, Y, Z)
Definition: md5.c:45
llvm::StringMap< std::unique_ptr< llvm::Module > > ModuleCache
llvm::SmallVector< InlineWorkListItem, 128 > InlineWorkList
#define Assert(condition)
Definition: c.h:732
struct FunctionInlineState FunctionInlineState
llvm::SmallVector< llvm::ModuleSummaryIndex *, 2 > InlineSearchPath
const float inline_cost_decay_factor
llvm::ManagedStatic< ModuleCache > module_cache
static std::unique_ptr< llvm::Module > load_module(llvm::StringRef Identifier)
void llvm_inline(LLVMModuleRef M)
static void add_module_to_inline_search_path(InlineSearchPath &path, llvm::StringRef modpath)
#define elog(elevel,...)
Definition: elog.h:226
#define ilog(...)
static std::unique_ptr< llvm::ModuleSummaryIndex > llvm_load_summary(llvm::StringRef path)
NameData * Name
Definition: c.h:607
static std::unique_ptr< ImportMapTy > llvm_build_inline_plan(llvm::Module *mod)
struct InlineWorkListItem InlineWorkListItem
static llvm::Function * create_redirection_function(std::unique_ptr< llvm::Module > &importMod, llvm::Function *F, llvm::StringRef Name)
#define snprintf
Definition: port.h:192
char pkglib_path[MAXPGPATH]
Definition: globals.c:73
static void llvm_execute_inline_plan(llvm::Module *mod, ImportMapTy *globalsToInline)