Line data Source code
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) 2016-2025, 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 : #include <llvm/Bitcode/BitcodeReader.h>
53 : #include <llvm/IR/Attributes.h>
54 : #include <llvm/IR/DebugInfo.h>
55 : #include <llvm/IR/IntrinsicInst.h>
56 : #include <llvm/IR/IRBuilder.h>
57 : #include <llvm/IR/ModuleSummaryIndex.h>
58 : #include <llvm/Linker/IRMover.h>
59 : #include <llvm/Support/ManagedStatic.h>
60 : #include <llvm/Support/MemoryBuffer.h>
61 :
62 :
63 : /*
64 : * Type used to represent modules InlineWorkListItem's subject is searched for
65 : * in.
66 : */
67 : typedef llvm::SmallVector<llvm::ModuleSummaryIndex *, 2> InlineSearchPath;
68 :
69 : /*
70 : * Item in queue of to-be-checked symbols and corresponding queue.
71 : */
72 : typedef struct InlineWorkListItem
73 : {
74 : llvm::StringRef symbolName;
75 : llvm::SmallVector<llvm::ModuleSummaryIndex *, 2> searchpath;
76 : } InlineWorkListItem;
77 : typedef llvm::SmallVector<InlineWorkListItem, 128> InlineWorkList;
78 :
79 : /*
80 : * Information about symbols processed during inlining. Used to prevent
81 : * repeated searches and provide additional information.
82 : */
83 : typedef struct FunctionInlineState
84 : {
85 : int costLimit;
86 : bool processed;
87 : bool inlined;
88 : bool allowReconsidering;
89 : } FunctionInlineState;
90 : typedef llvm::StringMap<FunctionInlineState> FunctionInlineStates;
91 :
92 : /*
93 : * Map of modules that should be inlined, with a list of the to-be inlined
94 : * symbols.
95 : */
96 : typedef llvm::StringMap<llvm::StringSet<> > ImportMapTy;
97 :
98 :
99 : const float inline_cost_decay_factor = 0.5;
100 : const int inline_initial_cost = 150;
101 :
102 : /*
103 : * These are managed statics so LLVM knows to deallocate them during an
104 : * LLVMShutdown(), rather than after (which'd cause crashes).
105 : */
106 : typedef llvm::StringMap<std::unique_ptr<llvm::Module> > ModuleCache;
107 : llvm::ManagedStatic<ModuleCache> module_cache;
108 : typedef llvm::StringMap<std::unique_ptr<llvm::ModuleSummaryIndex> > SummaryCache;
109 : llvm::ManagedStatic<SummaryCache> summary_cache;
110 :
111 :
112 : static std::unique_ptr<ImportMapTy> llvm_build_inline_plan(LLVMContextRef lc, llvm::Module *mod);
113 : static void llvm_execute_inline_plan(llvm::Module *mod,
114 : ImportMapTy *globalsToInline);
115 :
116 : static llvm::Module* load_module_cached(LLVMContextRef c, llvm::StringRef modPath);
117 : static std::unique_ptr<llvm::Module> load_module(LLVMContextRef c, llvm::StringRef Identifier);
118 : static std::unique_ptr<llvm::ModuleSummaryIndex> llvm_load_summary(llvm::StringRef path);
119 :
120 :
121 : static llvm::Function* create_redirection_function(std::unique_ptr<llvm::Module> &importMod,
122 : llvm::Function *F,
123 : llvm::StringRef Name);
124 :
125 : static bool function_inlinable(llvm::Function &F,
126 : int threshold,
127 : FunctionInlineStates &functionState,
128 : InlineWorkList &worklist,
129 : InlineSearchPath &searchpath,
130 : llvm::SmallPtrSet<const llvm::Function *, 8> &visitedFunctions,
131 : int &running_instcount,
132 : llvm::StringSet<> &importVars);
133 : static void function_references(llvm::Function &F,
134 : int &running_instcount,
135 : llvm::SmallPtrSet<llvm::GlobalVariable *, 8> &referencedVars,
136 : llvm::SmallPtrSet<llvm::Function *, 8> &referencedFunctions);
137 :
138 : static void add_module_to_inline_search_path(InlineSearchPath& path, llvm::StringRef modpath);
139 : static llvm::SmallVector<llvm::GlobalValueSummary *, 1>
140 : summaries_for_guid(const InlineSearchPath& path, llvm::GlobalValue::GUID guid);
141 :
142 : /* verbose debugging for inliner development */
143 : /* #define INLINE_DEBUG */
144 : #ifdef INLINE_DEBUG
145 : #define ilog elog
146 : #else
147 : #define ilog(...) (void) 0
148 : #endif
149 :
150 : /*
151 : * Reset inlining related state. This needs to be called before the currently
152 : * used LLVMContextRef is disposed (and a new one create), otherwise we would
153 : * have dangling references to deleted modules.
154 : */
155 : void
156 0 : llvm_inline_reset_caches(void)
157 : {
158 0 : module_cache->clear();
159 0 : summary_cache->clear();
160 0 : }
161 :
162 : /*
163 : * Perform inlining of external function references in M based on a simple
164 : * cost based analysis.
165 : */
166 : void
167 552 : llvm_inline(LLVMModuleRef M)
168 : {
169 552 : LLVMContextRef lc = LLVMGetModuleContext(M);
170 552 : llvm::Module *mod = llvm::unwrap(M);
171 :
172 552 : std::unique_ptr<ImportMapTy> globalsToInline = llvm_build_inline_plan(lc, mod);
173 552 : if (!globalsToInline)
174 0 : return;
175 552 : llvm_execute_inline_plan(mod, globalsToInline.get());
176 552 : }
177 :
178 : /*
179 : * Build information necessary for inlining external function references in
180 : * mod.
181 : */
182 : static std::unique_ptr<ImportMapTy>
183 552 : llvm_build_inline_plan(LLVMContextRef lc, llvm::Module *mod)
184 : {
185 552 : std::unique_ptr<ImportMapTy> globalsToInline(new ImportMapTy());
186 552 : FunctionInlineStates functionStates;
187 552 : InlineWorkList worklist;
188 :
189 552 : InlineSearchPath defaultSearchPath;
190 :
191 : /* attempt to add module to search path */
192 552 : add_module_to_inline_search_path(defaultSearchPath, "$libdir/postgres");
193 : /* if postgres isn't available, no point continuing */
194 552 : if (defaultSearchPath.empty())
195 0 : return nullptr;
196 :
197 : /*
198 : * Start inlining with current references to external functions by putting
199 : * them on the inlining worklist. If, during inlining of those, new extern
200 : * functions need to be inlined, they'll also be put there, with a lower
201 : * priority.
202 : */
203 10484 : for (const llvm::Function &funcDecl : mod->functions())
204 : {
205 9932 : InlineWorkListItem item = {};
206 9932 : FunctionInlineState inlineState = {};
207 :
208 : /* already has a definition */
209 9932 : if (!funcDecl.isDeclaration())
210 6828 : continue;
211 :
212 : /* llvm provides implementation */
213 3104 : if (funcDecl.isIntrinsic())
214 490 : continue;
215 :
216 2614 : item.symbolName = funcDecl.getName();
217 2614 : item.searchpath = defaultSearchPath;
218 2614 : worklist.push_back(item);
219 2614 : inlineState.costLimit = inline_initial_cost;
220 2614 : inlineState.processed = false;
221 2614 : inlineState.inlined = false;
222 2614 : inlineState.allowReconsidering = false;
223 2614 : functionStates[funcDecl.getName()] = inlineState;
224 9932 : }
225 :
226 : /*
227 : * Iterate over pending worklist items, look them up in index, check
228 : * whether they should be inlined.
229 : */
230 11364 : while (!worklist.empty())
231 : {
232 10812 : InlineWorkListItem item = worklist.pop_back_val();
233 10812 : llvm::StringRef symbolName = item.symbolName;
234 : char *cmodname;
235 : char *cfuncname;
236 10812 : FunctionInlineState &inlineState = functionStates[symbolName];
237 : llvm::GlobalValue::GUID funcGUID;
238 :
239 10812 : llvm_split_symbol_name(symbolName.data(), &cmodname, &cfuncname);
240 :
241 : #if LLVM_VERSION_MAJOR >= 21
242 : funcGUID = llvm::GlobalValue::getGUIDAssumingExternalLinkage(cfuncname);
243 : #else
244 10812 : funcGUID = llvm::GlobalValue::getGUID(cfuncname);
245 : #endif
246 :
247 : /* already processed */
248 10812 : if (inlineState.processed)
249 0 : continue;
250 :
251 :
252 10812 : if (cmodname)
253 0 : add_module_to_inline_search_path(item.searchpath, cmodname);
254 :
255 : /*
256 : * Iterate over all known definitions of function, via the index. Then
257 : * look up module(s), check if function actually is defined (there
258 : * could be hash conflicts).
259 : */
260 16342 : for (const auto &gvs : summaries_for_guid(item.searchpath, funcGUID))
261 : {
262 : const llvm::FunctionSummary *fs;
263 10076 : llvm::StringRef modPath = gvs->modulePath();
264 : llvm::Module *defMod;
265 : llvm::Function *funcDef;
266 :
267 10076 : fs = llvm::cast<llvm::FunctionSummary>(gvs);
268 :
269 10076 : if (gvs->notEligibleToImport())
270 : {
271 : ilog(DEBUG1, "ineligibile to import %s due to summary",
272 : symbolName.data());
273 4732 : continue;
274 : }
275 :
276 10076 : if ((int) fs->instCount() > inlineState.costLimit)
277 : {
278 : ilog(DEBUG1, "ineligibile to import %s due to early threshold: %u vs %u",
279 : symbolName.data(), fs->instCount(), inlineState.costLimit);
280 4124 : inlineState.allowReconsidering = true;
281 4124 : continue;
282 : }
283 :
284 5952 : defMod = load_module_cached(lc, modPath);
285 5952 : if (defMod->materializeMetadata())
286 0 : elog(FATAL, "failed to materialize metadata");
287 :
288 5952 : funcDef = defMod->getFunction(cfuncname);
289 :
290 : /*
291 : * This can happen e.g. in case of a hash collision of the
292 : * function's name.
293 : */
294 5952 : if (!funcDef)
295 0 : continue;
296 :
297 5952 : if (funcDef->materialize())
298 0 : elog(FATAL, "failed to materialize metadata");
299 :
300 : Assert(!funcDef->isDeclaration());
301 : Assert(funcDef->hasExternalLinkage());
302 :
303 5952 : llvm::StringSet<> importVars;
304 5952 : llvm::SmallPtrSet<const llvm::Function *, 8> visitedFunctions;
305 5952 : int running_instcount = 0;
306 :
307 : /*
308 : * Check whether function, and objects it depends on, are
309 : * inlinable.
310 : */
311 5952 : if (function_inlinable(*funcDef,
312 : inlineState.costLimit,
313 : functionStates,
314 : worklist,
315 : item.searchpath,
316 : visitedFunctions,
317 : running_instcount,
318 : importVars))
319 : {
320 : /*
321 : * Check whether function and all its dependencies are too
322 : * big. Dependencies already counted for other functions that
323 : * will get inlined are not counted again. While this make
324 : * things somewhat order dependent, I can't quite see a point
325 : * in a different behaviour.
326 : */
327 5154 : if (running_instcount > inlineState.costLimit)
328 : {
329 : ilog(DEBUG1, "skipping inlining of %s due to late threshold %d vs %d",
330 : symbolName.data(), running_instcount, inlineState.costLimit);
331 608 : inlineState.allowReconsidering = true;
332 608 : continue;
333 : }
334 :
335 : ilog(DEBUG1, "inline top function %s total_instcount: %d, partial: %d",
336 : symbolName.data(), running_instcount, fs->instCount());
337 :
338 : /* import referenced function itself */
339 4546 : importVars.insert(symbolName);
340 :
341 : {
342 4546 : llvm::StringSet<> &modGlobalsToInline = (*globalsToInline)[modPath];
343 11134 : for (auto& importVar : importVars)
344 6588 : modGlobalsToInline.insert(importVar.first());
345 : Assert(modGlobalsToInline.size() > 0);
346 : }
347 :
348 : /* mark function as inlined */
349 4546 : inlineState.inlined = true;
350 :
351 : /*
352 : * Found definition to inline, don't look for further
353 : * potential definitions.
354 : */
355 4546 : break;
356 : }
357 : else
358 : {
359 : ilog(DEBUG1, "had to skip inlining %s",
360 : symbolName.data());
361 :
362 : /* It's possible there's another definition that's inlinable. */
363 : }
364 21918 : }
365 :
366 : /*
367 : * Signal that we're done with symbol, whether successful (inlined =
368 : * true above) or not.
369 : */
370 10812 : inlineState.processed = true;
371 10812 : }
372 :
373 552 : return globalsToInline;
374 552 : }
375 :
376 : /*
377 : * Perform the actual inlining of external functions (and their dependencies)
378 : * into mod.
379 : */
380 : static void
381 552 : llvm_execute_inline_plan(llvm::Module *mod, ImportMapTy *globalsToInline)
382 : {
383 552 : llvm::IRMover Mover(*mod);
384 :
385 3646 : for (const auto& toInline : *globalsToInline)
386 : {
387 3094 : const llvm::StringRef& modPath = toInline.first();
388 3094 : const llvm::StringSet<>& modGlobalsToInline = toInline.second;
389 3094 : llvm::SetVector<llvm::GlobalValue *> GlobalsToImport;
390 :
391 : Assert(module_cache->count(modPath));
392 3094 : std::unique_ptr<llvm::Module> importMod(std::move((*module_cache)[modPath]));
393 3094 : module_cache->erase(modPath);
394 :
395 3094 : if (modGlobalsToInline.empty())
396 0 : continue;
397 :
398 9320 : for (auto &glob: modGlobalsToInline)
399 : {
400 6226 : llvm::StringRef SymbolName = glob.first();
401 : char *modname;
402 : char *funcname;
403 :
404 6226 : llvm_split_symbol_name(SymbolName.data(), &modname, &funcname);
405 :
406 6226 : llvm::GlobalValue *valueToImport = importMod->getNamedValue(funcname);
407 :
408 6226 : if (!valueToImport)
409 0 : elog(FATAL, "didn't refind value %s to import", SymbolName.data());
410 :
411 : /*
412 : * For functions (global vars are only inlined if already static),
413 : * mark imported variables as being clones from other
414 : * functions. That a) avoids symbol conflicts b) allows the
415 : * optimizer to perform inlining.
416 : */
417 6226 : if (llvm::isa<llvm::Function>(valueToImport))
418 : {
419 4636 : llvm::Function *F = llvm::dyn_cast<llvm::Function>(valueToImport);
420 : typedef llvm::GlobalValue::LinkageTypes LinkageTypes;
421 :
422 : /*
423 : * Per-function info isn't necessarily stripped yet, as the
424 : * module is lazy-loaded when stripped above.
425 : */
426 4636 : llvm::stripDebugInfo(*F);
427 :
428 : /*
429 : * If the to-be-imported function is one referenced including
430 : * its module name, create a tiny inline function that just
431 : * forwards the call. One might think a GlobalAlias would do
432 : * the trick, but a) IRMover doesn't override a declaration
433 : * with an alias pointing to a definition (instead renaming
434 : * it), b) Aliases can't be AvailableExternally.
435 : */
436 4636 : if (modname)
437 : {
438 : llvm::Function *AF;
439 :
440 0 : AF = create_redirection_function(importMod, F, SymbolName);
441 :
442 0 : GlobalsToImport.insert(AF);
443 0 : llvm::stripDebugInfo(*AF);
444 : }
445 :
446 4636 : if (valueToImport->hasExternalLinkage())
447 : {
448 4546 : valueToImport->setLinkage(LinkageTypes::AvailableExternallyLinkage);
449 : }
450 : }
451 :
452 6226 : GlobalsToImport.insert(valueToImport);
453 : ilog(DEBUG1, "performing import of %s %s",
454 : modPath.data(), SymbolName.data());
455 :
456 : }
457 :
458 3094 : if (Mover.move(std::move(importMod), GlobalsToImport.getArrayRef(),
459 972 : [](llvm::GlobalValue &, llvm::IRMover::ValueAdder) {},
460 : /*IsPerformingImport=*/false))
461 0 : elog(FATAL, "function import failed with linker error");
462 3094 : }
463 552 : }
464 :
465 : /*
466 : * Return a module identified by modPath, caching it in memory.
467 : *
468 : * Note that such a module may *not* be modified without copying, otherwise
469 : * the cache state would get corrupted.
470 : */
471 : static llvm::Module*
472 5952 : load_module_cached(LLVMContextRef lc, llvm::StringRef modPath)
473 : {
474 5952 : auto it = module_cache->find(modPath);
475 5952 : if (it == module_cache->end())
476 : {
477 6380 : it = module_cache->insert(
478 6380 : std::make_pair(modPath, load_module(lc, modPath))).first;
479 : }
480 :
481 5952 : return it->second.get();
482 : }
483 :
484 : static std::unique_ptr<llvm::Module>
485 3190 : load_module(LLVMContextRef lc, llvm::StringRef Identifier)
486 : {
487 : LLVMMemoryBufferRef buf;
488 : LLVMModuleRef mod;
489 : char path[MAXPGPATH];
490 : char *msg;
491 :
492 3190 : snprintf(path, MAXPGPATH,"%s/bitcode/%s", pkglib_path, Identifier.data());
493 :
494 3190 : if (LLVMCreateMemoryBufferWithContentsOfFile(path, &buf, &msg))
495 0 : elog(FATAL, "failed to open bitcode file \"%s\": %s",
496 : path, msg);
497 3190 : if (LLVMGetBitcodeModuleInContext2(lc, buf, &mod))
498 0 : elog(FATAL, "failed to parse bitcode in file \"%s\"", path);
499 :
500 : /*
501 : * Currently there's no use in more detailed debug info for JITed
502 : * code. Until that changes, not much point in wasting memory and cycles
503 : * on processing debuginfo.
504 : */
505 3190 : llvm::StripDebugInfo(*llvm::unwrap(mod));
506 :
507 6380 : return std::unique_ptr<llvm::Module>(llvm::unwrap(mod));
508 : }
509 :
510 : /*
511 : * Compute list of referenced variables, functions and the instruction count
512 : * for a function.
513 : */
514 : static void
515 10062 : function_references(llvm::Function &F,
516 : int &running_instcount,
517 : llvm::SmallPtrSet<llvm::GlobalVariable *, 8> &referencedVars,
518 : llvm::SmallPtrSet<llvm::Function *, 8> &referencedFunctions)
519 : {
520 10062 : llvm::SmallPtrSet<const llvm::User *, 32> Visited;
521 :
522 253358 : for (llvm::BasicBlock &BB : F)
523 : {
524 1321244 : for (llvm::Instruction &I : BB)
525 : {
526 599798 : if (llvm::isa<llvm::DbgInfoIntrinsic>(I))
527 0 : continue;
528 :
529 599798 : llvm::SmallVector<llvm::User *, 8> Worklist;
530 599798 : Worklist.push_back(&I);
531 :
532 599798 : running_instcount++;
533 :
534 2066492 : while (!Worklist.empty()) {
535 1466694 : llvm::User *U = Worklist.pop_back_val();
536 :
537 : /* visited before */
538 1466694 : if (!Visited.insert(U).second)
539 728016 : continue;
540 :
541 1970154 : for (auto &OI : U->operands()) {
542 1231476 : llvm::User *Operand = llvm::dyn_cast<llvm::User>(OI);
543 1231476 : if (!Operand)
544 407436 : continue;
545 974062 : if (llvm::isa<llvm::BlockAddress>(Operand))
546 0 : continue;
547 974062 : if (auto *GV = llvm::dyn_cast<llvm::GlobalVariable>(Operand)) {
548 44608 : referencedVars.insert(GV);
549 44608 : if (GV->hasInitializer())
550 42856 : Worklist.push_back(GV->getInitializer());
551 44608 : continue;
552 : }
553 929454 : if (auto *CF = llvm::dyn_cast<llvm::Function>(Operand)) {
554 105414 : referencedFunctions.insert(CF);
555 105414 : continue;
556 : }
557 824040 : Worklist.push_back(Operand);
558 : }
559 : }
560 599798 : }
561 : }
562 10062 : }
563 :
564 : /*
565 : * Check whether function F is inlinable and, if so, what globals need to be
566 : * imported.
567 : *
568 : * References to external functions from, potentially recursively, inlined
569 : * functions are added to the passed in worklist.
570 : */
571 : static bool
572 10110 : function_inlinable(llvm::Function &F,
573 : int threshold,
574 : FunctionInlineStates &functionStates,
575 : InlineWorkList &worklist,
576 : InlineSearchPath &searchpath,
577 : llvm::SmallPtrSet<const llvm::Function *, 8> &visitedFunctions,
578 : int &running_instcount,
579 : llvm::StringSet<> &importVars)
580 : {
581 10110 : int subThreshold = threshold * inline_cost_decay_factor;
582 10110 : llvm::SmallPtrSet<llvm::GlobalVariable *, 8> referencedVars;
583 10110 : llvm::SmallPtrSet<llvm::Function *, 8> referencedFunctions;
584 :
585 : /* can't rely on what may be inlined */
586 10110 : if (F.isInterposable())
587 0 : return false;
588 :
589 : /*
590 : * Can't rely on function being present. Alternatively we could create a
591 : * static version of these functions?
592 : */
593 10110 : if (F.hasAvailableExternallyLinkage())
594 0 : return false;
595 :
596 : ilog(DEBUG1, "checking inlinability of %s", F.getName().data());
597 :
598 10110 : if (F.materialize())
599 0 : elog(FATAL, "failed to materialize metadata");
600 :
601 10110 : if (F.getAttributes().hasFnAttr(llvm::Attribute::NoInline))
602 : {
603 : ilog(DEBUG1, "ineligibile to import %s due to noinline",
604 : F.getName().data());
605 48 : return false;
606 : }
607 :
608 10062 : function_references(F, running_instcount, referencedVars, referencedFunctions);
609 :
610 39664 : for (llvm::GlobalVariable* rv: referencedVars)
611 : {
612 30352 : if (rv->materialize())
613 0 : elog(FATAL, "failed to materialize metadata");
614 :
615 : /*
616 : * Don't inline functions that access thread local variables. That
617 : * doesn't work on current LLVM releases (but might in future).
618 : */
619 30352 : if (rv->isThreadLocal())
620 : {
621 : ilog(DEBUG1, "cannot inline %s due to thread-local variable %s",
622 : F.getName().data(), rv->getName().data());
623 750 : return false;
624 : }
625 :
626 : /*
627 : * Never want to inline externally visible vars, cheap enough to
628 : * reference.
629 : */
630 30352 : if (rv->hasExternalLinkage() || rv->hasAvailableExternallyLinkage())
631 768 : continue;
632 :
633 : /*
634 : * If variable is file-local, we need to inline it, to be able to
635 : * inline the function itself. Can't do that if the variable can be
636 : * modified, because they'd obviously get out of sync.
637 : *
638 : * XXX: Currently not a problem, but there'd be problems with
639 : * nontrivial initializers if they were allowed for postgres.
640 : */
641 29584 : if (!rv->isConstant())
642 : {
643 : ilog(DEBUG1, "cannot inline %s due to uncloneable variable %s",
644 : F.getName().data(), rv->getName().data());
645 750 : return false;
646 : }
647 :
648 : ilog(DEBUG1, "memorizing global var %s linkage %d for inlining",
649 : rv->getName().data(), (int)rv->getLinkage());
650 :
651 28834 : importVars.insert(rv->getName());
652 : /* small cost attributed to each cloned global */
653 28834 : running_instcount += 5;
654 : }
655 :
656 9312 : visitedFunctions.insert(&F);
657 :
658 : /*
659 : * Check referenced functions. Check whether used static ones are
660 : * inlinable, and remember external ones for inlining.
661 : */
662 58124 : for (llvm::Function* referencedFunction: referencedFunctions)
663 : {
664 48964 : llvm::StringSet<> recImportVars;
665 :
666 48964 : if (referencedFunction->materialize())
667 0 : elog(FATAL, "failed to materialize metadata");
668 :
669 48964 : if (referencedFunction->isIntrinsic())
670 6748 : continue;
671 :
672 : /* if already visited skip, otherwise remember */
673 42216 : if (!visitedFunctions.insert(referencedFunction).second)
674 19308 : continue;
675 :
676 : /*
677 : * We don't inline external functions directly here, instead we put
678 : * them on the worklist if appropriate and check them from
679 : * llvm_build_inline_plan().
680 : */
681 22908 : if (referencedFunction->hasExternalLinkage())
682 : {
683 18750 : llvm::StringRef funcName = referencedFunction->getName();
684 :
685 : /*
686 : * Don't bother checking for inlining if remaining cost budget is
687 : * very small.
688 : */
689 18750 : if (subThreshold < 5)
690 4612 : continue;
691 :
692 14138 : auto it = functionStates.find(funcName);
693 14138 : if (it == functionStates.end())
694 : {
695 : FunctionInlineState inlineState;
696 :
697 7824 : inlineState.costLimit = subThreshold;
698 7824 : inlineState.processed = false;
699 7824 : inlineState.inlined = false;
700 7824 : inlineState.allowReconsidering = false;
701 :
702 7824 : functionStates[funcName] = inlineState;
703 7824 : worklist.push_back({funcName, searchpath});
704 :
705 : ilog(DEBUG1,
706 : "considering extern function %s at %d for inlining",
707 : funcName.data(), subThreshold);
708 : }
709 6314 : else if (!it->second.inlined &&
710 10492 : (!it->second.processed || it->second.allowReconsidering) &&
711 10492 : it->second.costLimit < subThreshold)
712 : {
713 : /*
714 : * Update inlining threshold if higher. Need to re-queue
715 : * to be processed if already processed with lower
716 : * threshold.
717 : */
718 374 : if (it->second.processed)
719 : {
720 : ilog(DEBUG1,
721 : "reconsidering extern function %s at %d for inlining, increasing from %d",
722 : funcName.data(), subThreshold, it->second.costLimit);
723 :
724 374 : it->second.processed = false;
725 374 : it->second.allowReconsidering = false;
726 374 : worklist.push_back({funcName, searchpath});
727 : }
728 374 : it->second.costLimit = subThreshold;
729 : }
730 14138 : continue;
731 14138 : }
732 :
733 : /* can't rely on what may be inlined */
734 4158 : if (referencedFunction->isInterposable())
735 0 : return false;
736 :
737 4158 : if (!function_inlinable(*referencedFunction,
738 : subThreshold,
739 : functionStates,
740 : worklist,
741 : searchpath,
742 : visitedFunctions,
743 : running_instcount,
744 : recImportVars))
745 : {
746 : ilog(DEBUG1,
747 : "cannot inline %s due to required function %s not being inlinable",
748 : F.getName().data(), referencedFunction->getName().data());
749 152 : return false;
750 : }
751 :
752 : /* import referenced function itself */
753 4006 : importVars.insert(referencedFunction->getName());
754 :
755 : /* import referenced function and its dependents */
756 96446 : for (auto& recImportVar : recImportVars)
757 92440 : importVars.insert(recImportVar.first());
758 48964 : }
759 :
760 9160 : return true;
761 18308 : }
762 :
763 : /*
764 : * Attempt to load module summary located at path. Return empty pointer when
765 : * loading fails.
766 : */
767 : static std::unique_ptr<llvm::ModuleSummaryIndex>
768 384 : llvm_load_summary(llvm::StringRef path)
769 : {
770 : llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer> > MBOrErr =
771 384 : llvm::MemoryBuffer::getFile(path);
772 :
773 384 : if (std::error_code EC = MBOrErr.getError())
774 : {
775 : ilog(DEBUG1, "failed to open %s: %s", path.data(),
776 : EC.message().c_str());
777 : }
778 : else
779 : {
780 384 : llvm::MemoryBufferRef ref(*MBOrErr.get().get());
781 :
782 : llvm::Expected<std::unique_ptr<llvm::ModuleSummaryIndex> > IndexOrErr =
783 384 : llvm::getModuleSummaryIndex(ref);
784 384 : if (IndexOrErr)
785 384 : return std::move(IndexOrErr.get());
786 0 : elog(FATAL, "failed to load summary \"%s\": %s",
787 : path.data(),
788 : toString(IndexOrErr.takeError()).c_str());
789 384 : }
790 0 : return nullptr;
791 384 : }
792 :
793 : /*
794 : * Attempt to add modpath to the search path.
795 : */
796 : static void
797 552 : add_module_to_inline_search_path(InlineSearchPath& searchpath, llvm::StringRef modpath)
798 : {
799 : /* only extension in libdir are candidates for inlining for now */
800 : #if LLVM_VERSION_MAJOR < 16
801 : #define starts_with startswith
802 : #endif
803 552 : if (!modpath.starts_with("$libdir/"))
804 0 : return;
805 :
806 : /* if there's no match, attempt to load */
807 552 : auto it = summary_cache->find(modpath);
808 552 : if (it == summary_cache->end())
809 : {
810 384 : std::string path(modpath);
811 384 : path = path.replace(0, strlen("$libdir"), std::string(pkglib_path) + "/bitcode");
812 384 : path += ".index.bc";
813 384 : (*summary_cache)[modpath] = llvm_load_summary(path);
814 384 : it = summary_cache->find(modpath);
815 384 : }
816 :
817 : Assert(it != summary_cache->end());
818 :
819 : /* if the entry isn't NULL, it's validly loaded */
820 552 : if (it->second)
821 552 : searchpath.push_back(it->second.get());
822 : }
823 :
824 : /*
825 : * Search for all references for functions hashing to guid in the search path,
826 : * and return them in search path order.
827 : */
828 : static llvm::SmallVector<llvm::GlobalValueSummary *, 1>
829 10812 : summaries_for_guid(const InlineSearchPath& path, llvm::GlobalValue::GUID guid)
830 : {
831 10812 : llvm::SmallVector<llvm::GlobalValueSummary *, 1> matches;
832 :
833 21624 : for (auto index : path)
834 : {
835 10812 : llvm::ValueInfo funcVI = index->getValueInfo(guid);
836 :
837 : /* if index doesn't know function, we don't have a body, continue */
838 10812 : if (funcVI)
839 20152 : for (auto &gv : funcVI.getSummaryList())
840 10076 : matches.push_back(gv.get());
841 : }
842 :
843 10812 : return matches;
844 0 : }
845 :
846 : /*
847 : * Create inline wrapper with the name Name, redirecting the call to F.
848 : */
849 : static llvm::Function*
850 0 : create_redirection_function(std::unique_ptr<llvm::Module> &importMod,
851 : llvm::Function *F,
852 : llvm::StringRef Name)
853 : {
854 : typedef llvm::GlobalValue::LinkageTypes LinkageTypes;
855 :
856 0 : llvm::LLVMContext &Context = F->getContext();
857 0 : llvm::IRBuilder<> Builder(Context);
858 : llvm::Function *AF;
859 : llvm::BasicBlock *BB;
860 : llvm::CallInst *fwdcall;
861 :
862 0 : AF = llvm::Function::Create(F->getFunctionType(),
863 : LinkageTypes::AvailableExternallyLinkage,
864 : Name, importMod.get());
865 0 : BB = llvm::BasicBlock::Create(Context, "entry", AF);
866 :
867 0 : Builder.SetInsertPoint(BB);
868 0 : fwdcall = Builder.CreateCall(F, &*AF->arg_begin());
869 0 : fwdcall->addFnAttr(llvm::Attribute::AlwaysInline);
870 0 : Builder.CreateRet(fwdcall);
871 :
872 0 : return AF;
873 0 : }
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