LLVM  10.0.0svn
RewriteStatepointsForGC.cpp
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1 //===- RewriteStatepointsForGC.cpp - Make GC relocations explicit ---------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Rewrite call/invoke instructions so as to make potential relocations
10 // performed by the garbage collector explicit in the IR.
11 //
12 //===----------------------------------------------------------------------===//
13 
15 
16 #include "llvm/ADT/ArrayRef.h"
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/DenseSet.h"
19 #include "llvm/ADT/MapVector.h"
20 #include "llvm/ADT/None.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/ADT/SetVector.h"
24 #include "llvm/ADT/SmallSet.h"
25 #include "llvm/ADT/SmallVector.h"
26 #include "llvm/ADT/StringRef.h"
31 #include "llvm/IR/Argument.h"
32 #include "llvm/IR/Attributes.h"
33 #include "llvm/IR/BasicBlock.h"
34 #include "llvm/IR/CallingConv.h"
35 #include "llvm/IR/Constant.h"
36 #include "llvm/IR/Constants.h"
37 #include "llvm/IR/DataLayout.h"
38 #include "llvm/IR/DerivedTypes.h"
39 #include "llvm/IR/Dominators.h"
40 #include "llvm/IR/Function.h"
41 #include "llvm/IR/IRBuilder.h"
42 #include "llvm/IR/InstIterator.h"
43 #include "llvm/IR/InstrTypes.h"
44 #include "llvm/IR/Instruction.h"
45 #include "llvm/IR/Instructions.h"
46 #include "llvm/IR/IntrinsicInst.h"
47 #include "llvm/IR/Intrinsics.h"
48 #include "llvm/IR/LLVMContext.h"
49 #include "llvm/IR/MDBuilder.h"
50 #include "llvm/IR/Metadata.h"
51 #include "llvm/IR/Module.h"
52 #include "llvm/IR/Statepoint.h"
53 #include "llvm/IR/Type.h"
54 #include "llvm/IR/User.h"
55 #include "llvm/IR/Value.h"
56 #include "llvm/IR/ValueHandle.h"
57 #include "llvm/Pass.h"
58 #include "llvm/Support/Casting.h"
60 #include "llvm/Support/Compiler.h"
61 #include "llvm/Support/Debug.h"
64 #include "llvm/Transforms/Scalar.h"
68 #include <algorithm>
69 #include <cassert>
70 #include <cstddef>
71 #include <cstdint>
72 #include <iterator>
73 #include <set>
74 #include <string>
75 #include <utility>
76 #include <vector>
77 
78 #define DEBUG_TYPE "rewrite-statepoints-for-gc"
79 
80 using namespace llvm;
81 
82 // Print the liveset found at the insert location
83 static cl::opt<bool> PrintLiveSet("spp-print-liveset", cl::Hidden,
84  cl::init(false));
85 static cl::opt<bool> PrintLiveSetSize("spp-print-liveset-size", cl::Hidden,
86  cl::init(false));
87 
88 // Print out the base pointers for debugging
89 static cl::opt<bool> PrintBasePointers("spp-print-base-pointers", cl::Hidden,
90  cl::init(false));
91 
92 // Cost threshold measuring when it is profitable to rematerialize value instead
93 // of relocating it
94 static cl::opt<unsigned>
95 RematerializationThreshold("spp-rematerialization-threshold", cl::Hidden,
96  cl::init(6));
97 
98 #ifdef EXPENSIVE_CHECKS
99 static bool ClobberNonLive = true;
100 #else
101 static bool ClobberNonLive = false;
102 #endif
103 
104 static cl::opt<bool, true> ClobberNonLiveOverride("rs4gc-clobber-non-live",
105  cl::location(ClobberNonLive),
106  cl::Hidden);
107 
108 static cl::opt<bool>
109  AllowStatepointWithNoDeoptInfo("rs4gc-allow-statepoint-with-no-deopt-info",
110  cl::Hidden, cl::init(true));
111 
112 /// The IR fed into RewriteStatepointsForGC may have had attributes and
113 /// metadata implying dereferenceability that are no longer valid/correct after
114 /// RewriteStatepointsForGC has run. This is because semantically, after
115 /// RewriteStatepointsForGC runs, all calls to gc.statepoint "free" the entire
116 /// heap. stripNonValidData (conservatively) restores
117 /// correctness by erasing all attributes in the module that externally imply
118 /// dereferenceability. Similar reasoning also applies to the noalias
119 /// attributes and metadata. gc.statepoint can touch the entire heap including
120 /// noalias objects.
121 /// Apart from attributes and metadata, we also remove instructions that imply
122 /// constant physical memory: llvm.invariant.start.
123 static void stripNonValidData(Module &M);
124 
126 
128  ModuleAnalysisManager &AM) {
129  bool Changed = false;
130  auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
131  for (Function &F : M) {
132  // Nothing to do for declarations.
133  if (F.isDeclaration() || F.empty())
134  continue;
135 
136  // Policy choice says not to rewrite - the most common reason is that we're
137  // compiling code without a GCStrategy.
139  continue;
140 
141  auto &DT = FAM.getResult<DominatorTreeAnalysis>(F);
142  auto &TTI = FAM.getResult<TargetIRAnalysis>(F);
143  auto &TLI = FAM.getResult<TargetLibraryAnalysis>(F);
144  Changed |= runOnFunction(F, DT, TTI, TLI);
145  }
146  if (!Changed)
147  return PreservedAnalyses::all();
148 
149  // stripNonValidData asserts that shouldRewriteStatepointsIn
150  // returns true for at least one function in the module. Since at least
151  // one function changed, we know that the precondition is satisfied.
153 
157  return PA;
158 }
159 
160 namespace {
161 
162 class RewriteStatepointsForGCLegacyPass : public ModulePass {
164 
165 public:
166  static char ID; // Pass identification, replacement for typeid
167 
168  RewriteStatepointsForGCLegacyPass() : ModulePass(ID), Impl() {
171  }
172 
173  bool runOnModule(Module &M) override {
174  bool Changed = false;
175  for (Function &F : M) {
176  // Nothing to do for declarations.
177  if (F.isDeclaration() || F.empty())
178  continue;
179 
180  // Policy choice says not to rewrite - the most common reason is that
181  // we're compiling code without a GCStrategy.
183  continue;
184 
185  TargetTransformInfo &TTI =
186  getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
187  const TargetLibraryInfo &TLI =
188  getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
189  auto &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
190 
191  Changed |= Impl.runOnFunction(F, DT, TTI, TLI);
192  }
193 
194  if (!Changed)
195  return false;
196 
197  // stripNonValidData asserts that shouldRewriteStatepointsIn
198  // returns true for at least one function in the module. Since at least
199  // one function changed, we know that the precondition is satisfied.
201  return true;
202  }
203 
204  void getAnalysisUsage(AnalysisUsage &AU) const override {
205  // We add and rewrite a bunch of instructions, but don't really do much
206  // else. We could in theory preserve a lot more analyses here.
210  }
211 };
212 
213 } // end anonymous namespace
214 
216 
218  return new RewriteStatepointsForGCLegacyPass();
219 }
220 
221 INITIALIZE_PASS_BEGIN(RewriteStatepointsForGCLegacyPass,
222  "rewrite-statepoints-for-gc",
223  "Make relocations explicit at statepoints", false, false)
226 INITIALIZE_PASS_END(RewriteStatepointsForGCLegacyPass,
227  "rewrite-statepoints-for-gc",
228  "Make relocations explicit at statepoints", false, false)
229 
230 namespace {
231 
233  /// Values defined in this block.
235 
236  /// Values used in this block (and thus live); does not included values
237  /// killed within this block.
239 
240  /// Values live into this basic block (i.e. used by any
241  /// instruction in this basic block or ones reachable from here)
243 
244  /// Values live out of this basic block (i.e. live into
245  /// any successor block)
247 };
248 
249 // The type of the internal cache used inside the findBasePointers family
250 // of functions. From the callers perspective, this is an opaque type and
251 // should not be inspected.
252 //
253 // In the actual implementation this caches two relations:
254 // - The base relation itself (i.e. this pointer is based on that one)
255 // - The base defining value relation (i.e. before base_phi insertion)
256 // Generally, after the execution of a full findBasePointer call, only the
257 // base relation will remain. Internally, we add a mixture of the two
258 // types, then update all the second type to the first type
263 
265  /// The set of values known to be live across this safepoint
267 
268  /// Mapping from live pointers to a base-defining-value
270 
271  /// The *new* gc.statepoint instruction itself. This produces the token
272  /// that normal path gc.relocates and the gc.result are tied to.
274 
275  /// Instruction to which exceptional gc relocates are attached
276  /// Makes it easier to iterate through them during relocationViaAlloca.
278 
279  /// Record live values we are rematerialized instead of relocating.
280  /// They are not included into 'LiveSet' field.
281  /// Maps rematerialized copy to it's original value.
283 };
284 
285 } // end anonymous namespace
286 
288  Optional<OperandBundleUse> DeoptBundle =
290 
291  if (!DeoptBundle.hasValue()) {
293  "Found non-leaf call without deopt info!");
294  return None;
295  }
296 
297  return DeoptBundle.getValue().Inputs;
298 }
299 
300 /// Compute the live-in set for every basic block in the function
301 static void computeLiveInValues(DominatorTree &DT, Function &F,
302  GCPtrLivenessData &Data);
303 
304 /// Given results from the dataflow liveness computation, find the set of live
305 /// Values at a particular instruction.
306 static void findLiveSetAtInst(Instruction *inst, GCPtrLivenessData &Data,
307  StatepointLiveSetTy &out);
308 
309 // TODO: Once we can get to the GCStrategy, this becomes
310 // Optional<bool> isGCManagedPointer(const Type *Ty) const override {
311 
312 static bool isGCPointerType(Type *T) {
313  if (auto *PT = dyn_cast<PointerType>(T))
314  // For the sake of this example GC, we arbitrarily pick addrspace(1) as our
315  // GC managed heap. We know that a pointer into this heap needs to be
316  // updated and that no other pointer does.
317  return PT->getAddressSpace() == 1;
318  return false;
319 }
320 
321 // Return true if this type is one which a) is a gc pointer or contains a GC
322 // pointer and b) is of a type this code expects to encounter as a live value.
323 // (The insertion code will assert that a type which matches (a) and not (b)
324 // is not encountered.)
326  // We fully support gc pointers
327  if (isGCPointerType(T))
328  return true;
329  // We partially support vectors of gc pointers. The code will assert if it
330  // can't handle something.
331  if (auto VT = dyn_cast<VectorType>(T))
332  if (isGCPointerType(VT->getElementType()))
333  return true;
334  return false;
335 }
336 
337 #ifndef NDEBUG
338 /// Returns true if this type contains a gc pointer whether we know how to
339 /// handle that type or not.
340 static bool containsGCPtrType(Type *Ty) {
341  if (isGCPointerType(Ty))
342  return true;
343  if (VectorType *VT = dyn_cast<VectorType>(Ty))
344  return isGCPointerType(VT->getScalarType());
345  if (ArrayType *AT = dyn_cast<ArrayType>(Ty))
346  return containsGCPtrType(AT->getElementType());
347  if (StructType *ST = dyn_cast<StructType>(Ty))
348  return llvm::any_of(ST->elements(), containsGCPtrType);
349  return false;
350 }
351 
352 // Returns true if this is a type which a) is a gc pointer or contains a GC
353 // pointer and b) is of a type which the code doesn't expect (i.e. first class
354 // aggregates). Used to trip assertions.
355 static bool isUnhandledGCPointerType(Type *Ty) {
356  return containsGCPtrType(Ty) && !isHandledGCPointerType(Ty);
357 }
358 #endif
359 
360 // Return the name of the value suffixed with the provided value, or if the
361 // value didn't have a name, the default value specified.
362 static std::string suffixed_name_or(Value *V, StringRef Suffix,
363  StringRef DefaultName) {
364  return V->hasName() ? (V->getName() + Suffix).str() : DefaultName.str();
365 }
366 
367 // Conservatively identifies any definitions which might be live at the
368 // given instruction. The analysis is performed immediately before the
369 // given instruction. Values defined by that instruction are not considered
370 // live. Values used by that instruction are considered live.
372  DominatorTree &DT, GCPtrLivenessData &OriginalLivenessData, CallBase *Call,
373  PartiallyConstructedSafepointRecord &Result) {
374  StatepointLiveSetTy LiveSet;
375  findLiveSetAtInst(Call, OriginalLivenessData, LiveSet);
376 
377  if (PrintLiveSet) {
378  dbgs() << "Live Variables:\n";
379  for (Value *V : LiveSet)
380  dbgs() << " " << V->getName() << " " << *V << "\n";
381  }
382  if (PrintLiveSetSize) {
383  dbgs() << "Safepoint For: " << Call->getCalledValue()->getName() << "\n";
384  dbgs() << "Number live values: " << LiveSet.size() << "\n";
385  }
386  Result.LiveSet = LiveSet;
387 }
388 
389 static bool isKnownBaseResult(Value *V);
390 
391 namespace {
392 
393 /// A single base defining value - An immediate base defining value for an
394 /// instruction 'Def' is an input to 'Def' whose base is also a base of 'Def'.
395 /// For instructions which have multiple pointer [vector] inputs or that
396 /// transition between vector and scalar types, there is no immediate base
397 /// defining value. The 'base defining value' for 'Def' is the transitive
398 /// closure of this relation stopping at the first instruction which has no
399 /// immediate base defining value. The b.d.v. might itself be a base pointer,
400 /// but it can also be an arbitrary derived pointer.
401 struct BaseDefiningValueResult {
402  /// Contains the value which is the base defining value.
403  Value * const BDV;
404 
405  /// True if the base defining value is also known to be an actual base
406  /// pointer.
407  const bool IsKnownBase;
408 
409  BaseDefiningValueResult(Value *BDV, bool IsKnownBase)
410  : BDV(BDV), IsKnownBase(IsKnownBase) {
411 #ifndef NDEBUG
412  // Check consistency between new and old means of checking whether a BDV is
413  // a base.
414  bool MustBeBase = isKnownBaseResult(BDV);
415  assert(!MustBeBase || MustBeBase == IsKnownBase);
416 #endif
417  }
418 };
419 
420 } // end anonymous namespace
421 
422 static BaseDefiningValueResult findBaseDefiningValue(Value *I);
423 
424 /// Return a base defining value for the 'Index' element of the given vector
425 /// instruction 'I'. If Index is null, returns a BDV for the entire vector
426 /// 'I'. As an optimization, this method will try to determine when the
427 /// element is known to already be a base pointer. If this can be established,
428 /// the second value in the returned pair will be true. Note that either a
429 /// vector or a pointer typed value can be returned. For the former, the
430 /// vector returned is a BDV (and possibly a base) of the entire vector 'I'.
431 /// If the later, the return pointer is a BDV (or possibly a base) for the
432 /// particular element in 'I'.
433 static BaseDefiningValueResult
435  // Each case parallels findBaseDefiningValue below, see that code for
436  // detailed motivation.
437 
438  if (isa<Argument>(I))
439  // An incoming argument to the function is a base pointer
440  return BaseDefiningValueResult(I, true);
441 
442  if (isa<Constant>(I))
443  // Base of constant vector consists only of constant null pointers.
444  // For reasoning see similar case inside 'findBaseDefiningValue' function.
445  return BaseDefiningValueResult(ConstantAggregateZero::get(I->getType()),
446  true);
447 
448  if (isa<LoadInst>(I))
449  return BaseDefiningValueResult(I, true);
450 
451  if (isa<InsertElementInst>(I))
452  // We don't know whether this vector contains entirely base pointers or
453  // not. To be conservatively correct, we treat it as a BDV and will
454  // duplicate code as needed to construct a parallel vector of bases.
455  return BaseDefiningValueResult(I, false);
456 
457  if (isa<ShuffleVectorInst>(I))
458  // We don't know whether this vector contains entirely base pointers or
459  // not. To be conservatively correct, we treat it as a BDV and will
460  // duplicate code as needed to construct a parallel vector of bases.
461  // TODO: There a number of local optimizations which could be applied here
462  // for particular sufflevector patterns.
463  return BaseDefiningValueResult(I, false);
464 
465  // The behavior of getelementptr instructions is the same for vector and
466  // non-vector data types.
467  if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
468  return findBaseDefiningValue(GEP->getPointerOperand());
469 
470  // If the pointer comes through a bitcast of a vector of pointers to
471  // a vector of another type of pointer, then look through the bitcast
472  if (auto *BC = dyn_cast<BitCastInst>(I))
473  return findBaseDefiningValue(BC->getOperand(0));
474 
475  // We assume that functions in the source language only return base
476  // pointers. This should probably be generalized via attributes to support
477  // both source language and internal functions.
478  if (isa<CallInst>(I) || isa<InvokeInst>(I))
479  return BaseDefiningValueResult(I, true);
480 
481  // A PHI or Select is a base defining value. The outer findBasePointer
482  // algorithm is responsible for constructing a base value for this BDV.
483  assert((isa<SelectInst>(I) || isa<PHINode>(I)) &&
484  "unknown vector instruction - no base found for vector element");
485  return BaseDefiningValueResult(I, false);
486 }
487 
488 /// Helper function for findBasePointer - Will return a value which either a)
489 /// defines the base pointer for the input, b) blocks the simple search
490 /// (i.e. a PHI or Select of two derived pointers), or c) involves a change
491 /// from pointer to vector type or back.
492 static BaseDefiningValueResult findBaseDefiningValue(Value *I) {
494  "Illegal to ask for the base pointer of a non-pointer type");
495 
496  if (I->getType()->isVectorTy())
498 
499  if (isa<Argument>(I))
500  // An incoming argument to the function is a base pointer
501  // We should have never reached here if this argument isn't an gc value
502  return BaseDefiningValueResult(I, true);
503 
504  if (isa<Constant>(I)) {
505  // We assume that objects with a constant base (e.g. a global) can't move
506  // and don't need to be reported to the collector because they are always
507  // live. Besides global references, all kinds of constants (e.g. undef,
508  // constant expressions, null pointers) can be introduced by the inliner or
509  // the optimizer, especially on dynamically dead paths.
510  // Here we treat all of them as having single null base. By doing this we
511  // trying to avoid problems reporting various conflicts in a form of
512  // "phi (const1, const2)" or "phi (const, regular gc ptr)".
513  // See constant.ll file for relevant test cases.
514 
515  return BaseDefiningValueResult(
516  ConstantPointerNull::get(cast<PointerType>(I->getType())), true);
517  }
518 
519  if (CastInst *CI = dyn_cast<CastInst>(I)) {
520  Value *Def = CI->stripPointerCasts();
521  // If stripping pointer casts changes the address space there is an
522  // addrspacecast in between.
523  assert(cast<PointerType>(Def->getType())->getAddressSpace() ==
524  cast<PointerType>(CI->getType())->getAddressSpace() &&
525  "unsupported addrspacecast");
526  // If we find a cast instruction here, it means we've found a cast which is
527  // not simply a pointer cast (i.e. an inttoptr). We don't know how to
528  // handle int->ptr conversion.
529  assert(!isa<CastInst>(Def) && "shouldn't find another cast here");
530  return findBaseDefiningValue(Def);
531  }
532 
533  if (isa<LoadInst>(I))
534  // The value loaded is an gc base itself
535  return BaseDefiningValueResult(I, true);
536 
537  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I))
538  // The base of this GEP is the base
539  return findBaseDefiningValue(GEP->getPointerOperand());
540 
541  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
542  switch (II->getIntrinsicID()) {
543  default:
544  // fall through to general call handling
545  break;
546  case Intrinsic::experimental_gc_statepoint:
547  llvm_unreachable("statepoints don't produce pointers");
548  case Intrinsic::experimental_gc_relocate:
549  // Rerunning safepoint insertion after safepoints are already
550  // inserted is not supported. It could probably be made to work,
551  // but why are you doing this? There's no good reason.
552  llvm_unreachable("repeat safepoint insertion is not supported");
553  case Intrinsic::gcroot:
554  // Currently, this mechanism hasn't been extended to work with gcroot.
555  // There's no reason it couldn't be, but I haven't thought about the
556  // implications much.
558  "interaction with the gcroot mechanism is not supported");
559  }
560  }
561  // We assume that functions in the source language only return base
562  // pointers. This should probably be generalized via attributes to support
563  // both source language and internal functions.
564  if (isa<CallInst>(I) || isa<InvokeInst>(I))
565  return BaseDefiningValueResult(I, true);
566 
567  // TODO: I have absolutely no idea how to implement this part yet. It's not
568  // necessarily hard, I just haven't really looked at it yet.
569  assert(!isa<LandingPadInst>(I) && "Landing Pad is unimplemented");
570 
571  if (isa<AtomicCmpXchgInst>(I))
572  // A CAS is effectively a atomic store and load combined under a
573  // predicate. From the perspective of base pointers, we just treat it
574  // like a load.
575  return BaseDefiningValueResult(I, true);
576 
577  assert(!isa<AtomicRMWInst>(I) && "Xchg handled above, all others are "
578  "binary ops which don't apply to pointers");
579 
580  // The aggregate ops. Aggregates can either be in the heap or on the
581  // stack, but in either case, this is simply a field load. As a result,
582  // this is a defining definition of the base just like a load is.
583  if (isa<ExtractValueInst>(I))
584  return BaseDefiningValueResult(I, true);
585 
586  // We should never see an insert vector since that would require we be
587  // tracing back a struct value not a pointer value.
588  assert(!isa<InsertValueInst>(I) &&
589  "Base pointer for a struct is meaningless");
590 
591  // An extractelement produces a base result exactly when it's input does.
592  // We may need to insert a parallel instruction to extract the appropriate
593  // element out of the base vector corresponding to the input. Given this,
594  // it's analogous to the phi and select case even though it's not a merge.
595  if (isa<ExtractElementInst>(I))
596  // Note: There a lot of obvious peephole cases here. This are deliberately
597  // handled after the main base pointer inference algorithm to make writing
598  // test cases to exercise that code easier.
599  return BaseDefiningValueResult(I, false);
600 
601  // The last two cases here don't return a base pointer. Instead, they
602  // return a value which dynamically selects from among several base
603  // derived pointers (each with it's own base potentially). It's the job of
604  // the caller to resolve these.
605  assert((isa<SelectInst>(I) || isa<PHINode>(I)) &&
606  "missing instruction case in findBaseDefiningValing");
607  return BaseDefiningValueResult(I, false);
608 }
609 
610 /// Returns the base defining value for this value.
612  Value *&Cached = Cache[I];
613  if (!Cached) {
614  Cached = findBaseDefiningValue(I).BDV;
615  LLVM_DEBUG(dbgs() << "fBDV-cached: " << I->getName() << " -> "
616  << Cached->getName() << "\n");
617  }
618  assert(Cache[I] != nullptr);
619  return Cached;
620 }
621 
622 /// Return a base pointer for this value if known. Otherwise, return it's
623 /// base defining value.
626  auto Found = Cache.find(Def);
627  if (Found != Cache.end()) {
628  // Either a base-of relation, or a self reference. Caller must check.
629  return Found->second;
630  }
631  // Only a BDV available
632  return Def;
633 }
634 
635 /// Given the result of a call to findBaseDefiningValue, or findBaseOrBDV,
636 /// is it known to be a base pointer? Or do we need to continue searching.
637 static bool isKnownBaseResult(Value *V) {
638  if (!isa<PHINode>(V) && !isa<SelectInst>(V) &&
639  !isa<ExtractElementInst>(V) && !isa<InsertElementInst>(V) &&
640  !isa<ShuffleVectorInst>(V)) {
641  // no recursion possible
642  return true;
643  }
644  if (isa<Instruction>(V) &&
645  cast<Instruction>(V)->getMetadata("is_base_value")) {
646  // This is a previously inserted base phi or select. We know
647  // that this is a base value.
648  return true;
649  }
650 
651  // We need to keep searching
652  return false;
653 }
654 
655 namespace {
656 
657 /// Models the state of a single base defining value in the findBasePointer
658 /// algorithm for determining where a new instruction is needed to propagate
659 /// the base of this BDV.
660 class BDVState {
661 public:
662  enum Status { Unknown, Base, Conflict };
663 
664  BDVState() : BaseValue(nullptr) {}
665 
666  explicit BDVState(Status Status, Value *BaseValue = nullptr)
667  : Status(Status), BaseValue(BaseValue) {
668  assert(Status != Base || BaseValue);
669  }
670 
671  explicit BDVState(Value *BaseValue) : Status(Base), BaseValue(BaseValue) {}
672 
673  Status getStatus() const { return Status; }
674  Value *getBaseValue() const { return BaseValue; }
675 
676  bool isBase() const { return getStatus() == Base; }
677  bool isUnknown() const { return getStatus() == Unknown; }
678  bool isConflict() const { return getStatus() == Conflict; }
679 
680  bool operator==(const BDVState &Other) const {
681  return BaseValue == Other.BaseValue && Status == Other.Status;
682  }
683 
684  bool operator!=(const BDVState &other) const { return !(*this == other); }
685 
687  void dump() const {
688  print(dbgs());
689  dbgs() << '\n';
690  }
691 
692  void print(raw_ostream &OS) const {
693  switch (getStatus()) {
694  case Unknown:
695  OS << "U";
696  break;
697  case Base:
698  OS << "B";
699  break;
700  case Conflict:
701  OS << "C";
702  break;
703  }
704  OS << " (" << getBaseValue() << " - "
705  << (getBaseValue() ? getBaseValue()->getName() : "nullptr") << "): ";
706  }
707 
708 private:
709  Status Status = Unknown;
710  AssertingVH<Value> BaseValue; // Non-null only if Status == Base.
711 };
712 
713 } // end anonymous namespace
714 
715 #ifndef NDEBUG
716 static raw_ostream &operator<<(raw_ostream &OS, const BDVState &State) {
717  State.print(OS);
718  return OS;
719 }
720 #endif
721 
722 static BDVState meetBDVStateImpl(const BDVState &LHS, const BDVState &RHS) {
723  switch (LHS.getStatus()) {
724  case BDVState::Unknown:
725  return RHS;
726 
727  case BDVState::Base:
728  assert(LHS.getBaseValue() && "can't be null");
729  if (RHS.isUnknown())
730  return LHS;
731 
732  if (RHS.isBase()) {
733  if (LHS.getBaseValue() == RHS.getBaseValue()) {
734  assert(LHS == RHS && "equality broken!");
735  return LHS;
736  }
737  return BDVState(BDVState::Conflict);
738  }
739  assert(RHS.isConflict() && "only three states!");
740  return BDVState(BDVState::Conflict);
741 
742  case BDVState::Conflict:
743  return LHS;
744  }
745  llvm_unreachable("only three states!");
746 }
747 
748 // Values of type BDVState form a lattice, and this function implements the meet
749 // operation.
750 static BDVState meetBDVState(const BDVState &LHS, const BDVState &RHS) {
751  BDVState Result = meetBDVStateImpl(LHS, RHS);
752  assert(Result == meetBDVStateImpl(RHS, LHS) &&
753  "Math is wrong: meet does not commute!");
754  return Result;
755 }
756 
757 /// For a given value or instruction, figure out what base ptr its derived from.
758 /// For gc objects, this is simply itself. On success, returns a value which is
759 /// the base pointer. (This is reliable and can be used for relocation.) On
760 /// failure, returns nullptr.
762  Value *Def = findBaseOrBDV(I, Cache);
763 
764  if (isKnownBaseResult(Def))
765  return Def;
766 
767  // Here's the rough algorithm:
768  // - For every SSA value, construct a mapping to either an actual base
769  // pointer or a PHI which obscures the base pointer.
770  // - Construct a mapping from PHI to unknown TOP state. Use an
771  // optimistic algorithm to propagate base pointer information. Lattice
772  // looks like:
773  // UNKNOWN
774  // b1 b2 b3 b4
775  // CONFLICT
776  // When algorithm terminates, all PHIs will either have a single concrete
777  // base or be in a conflict state.
778  // - For every conflict, insert a dummy PHI node without arguments. Add
779  // these to the base[Instruction] = BasePtr mapping. For every
780  // non-conflict, add the actual base.
781  // - For every conflict, add arguments for the base[a] of each input
782  // arguments.
783  //
784  // Note: A simpler form of this would be to add the conflict form of all
785  // PHIs without running the optimistic algorithm. This would be
786  // analogous to pessimistic data flow and would likely lead to an
787  // overall worse solution.
788 
789 #ifndef NDEBUG
790  auto isExpectedBDVType = [](Value *BDV) {
791  return isa<PHINode>(BDV) || isa<SelectInst>(BDV) ||
792  isa<ExtractElementInst>(BDV) || isa<InsertElementInst>(BDV) ||
793  isa<ShuffleVectorInst>(BDV);
794  };
795 #endif
796 
797  // Once populated, will contain a mapping from each potentially non-base BDV
798  // to a lattice value (described above) which corresponds to that BDV.
799  // We use the order of insertion (DFS over the def/use graph) to provide a
800  // stable deterministic ordering for visiting DenseMaps (which are unordered)
801  // below. This is important for deterministic compilation.
803 
804  // Recursively fill in all base defining values reachable from the initial
805  // one for which we don't already know a definite base value for
806  /* scope */ {
807  SmallVector<Value*, 16> Worklist;
808  Worklist.push_back(Def);
809  States.insert({Def, BDVState()});
810  while (!Worklist.empty()) {
811  Value *Current = Worklist.pop_back_val();
812  assert(!isKnownBaseResult(Current) && "why did it get added?");
813 
814  auto visitIncomingValue = [&](Value *InVal) {
815  Value *Base = findBaseOrBDV(InVal, Cache);
816  if (isKnownBaseResult(Base))
817  // Known bases won't need new instructions introduced and can be
818  // ignored safely
819  return;
820  assert(isExpectedBDVType(Base) && "the only non-base values "
821  "we see should be base defining values");
822  if (States.insert(std::make_pair(Base, BDVState())).second)
823  Worklist.push_back(Base);
824  };
825  if (PHINode *PN = dyn_cast<PHINode>(Current)) {
826  for (Value *InVal : PN->incoming_values())
827  visitIncomingValue(InVal);
828  } else if (SelectInst *SI = dyn_cast<SelectInst>(Current)) {
829  visitIncomingValue(SI->getTrueValue());
830  visitIncomingValue(SI->getFalseValue());
831  } else if (auto *EE = dyn_cast<ExtractElementInst>(Current)) {
832  visitIncomingValue(EE->getVectorOperand());
833  } else if (auto *IE = dyn_cast<InsertElementInst>(Current)) {
834  visitIncomingValue(IE->getOperand(0)); // vector operand
835  visitIncomingValue(IE->getOperand(1)); // scalar operand
836  } else if (auto *SV = dyn_cast<ShuffleVectorInst>(Current)) {
837  visitIncomingValue(SV->getOperand(0));
838  visitIncomingValue(SV->getOperand(1));
839  }
840  else {
841  llvm_unreachable("Unimplemented instruction case");
842  }
843  }
844  }
845 
846 #ifndef NDEBUG
847  LLVM_DEBUG(dbgs() << "States after initialization:\n");
848  for (auto Pair : States) {
849  LLVM_DEBUG(dbgs() << " " << Pair.second << " for " << *Pair.first << "\n");
850  }
851 #endif
852 
853  // Return a phi state for a base defining value. We'll generate a new
854  // base state for known bases and expect to find a cached state otherwise.
855  auto getStateForBDV = [&](Value *baseValue) {
856  if (isKnownBaseResult(baseValue))
857  return BDVState(baseValue);
858  auto I = States.find(baseValue);
859  assert(I != States.end() && "lookup failed!");
860  return I->second;
861  };
862 
863  bool Progress = true;
864  while (Progress) {
865 #ifndef NDEBUG
866  const size_t OldSize = States.size();
867 #endif
868  Progress = false;
869  // We're only changing values in this loop, thus safe to keep iterators.
870  // Since this is computing a fixed point, the order of visit does not
871  // effect the result. TODO: We could use a worklist here and make this run
872  // much faster.
873  for (auto Pair : States) {
874  Value *BDV = Pair.first;
875  assert(!isKnownBaseResult(BDV) && "why did it get added?");
876 
877  // Given an input value for the current instruction, return a BDVState
878  // instance which represents the BDV of that value.
879  auto getStateForInput = [&](Value *V) mutable {
880  Value *BDV = findBaseOrBDV(V, Cache);
881  return getStateForBDV(BDV);
882  };
883 
884  BDVState NewState;
885  if (SelectInst *SI = dyn_cast<SelectInst>(BDV)) {
886  NewState = meetBDVState(NewState, getStateForInput(SI->getTrueValue()));
887  NewState =
888  meetBDVState(NewState, getStateForInput(SI->getFalseValue()));
889  } else if (PHINode *PN = dyn_cast<PHINode>(BDV)) {
890  for (Value *Val : PN->incoming_values())
891  NewState = meetBDVState(NewState, getStateForInput(Val));
892  } else if (auto *EE = dyn_cast<ExtractElementInst>(BDV)) {
893  // The 'meet' for an extractelement is slightly trivial, but it's still
894  // useful in that it drives us to conflict if our input is.
895  NewState =
896  meetBDVState(NewState, getStateForInput(EE->getVectorOperand()));
897  } else if (auto *IE = dyn_cast<InsertElementInst>(BDV)){
898  // Given there's a inherent type mismatch between the operands, will
899  // *always* produce Conflict.
900  NewState = meetBDVState(NewState, getStateForInput(IE->getOperand(0)));
901  NewState = meetBDVState(NewState, getStateForInput(IE->getOperand(1)));
902  } else {
903  // The only instance this does not return a Conflict is when both the
904  // vector operands are the same vector.
905  auto *SV = cast<ShuffleVectorInst>(BDV);
906  NewState = meetBDVState(NewState, getStateForInput(SV->getOperand(0)));
907  NewState = meetBDVState(NewState, getStateForInput(SV->getOperand(1)));
908  }
909 
910  BDVState OldState = States[BDV];
911  if (OldState != NewState) {
912  Progress = true;
913  States[BDV] = NewState;
914  }
915  }
916 
917  assert(OldSize == States.size() &&
918  "fixed point shouldn't be adding any new nodes to state");
919  }
920 
921 #ifndef NDEBUG
922  LLVM_DEBUG(dbgs() << "States after meet iteration:\n");
923  for (auto Pair : States) {
924  LLVM_DEBUG(dbgs() << " " << Pair.second << " for " << *Pair.first << "\n");
925  }
926 #endif
927 
928  // Insert Phis for all conflicts
929  // TODO: adjust naming patterns to avoid this order of iteration dependency
930  for (auto Pair : States) {
931  Instruction *I = cast<Instruction>(Pair.first);
932  BDVState State = Pair.second;
933  assert(!isKnownBaseResult(I) && "why did it get added?");
934  assert(!State.isUnknown() && "Optimistic algorithm didn't complete!");
935 
936  // extractelement instructions are a bit special in that we may need to
937  // insert an extract even when we know an exact base for the instruction.
938  // The problem is that we need to convert from a vector base to a scalar
939  // base for the particular indice we're interested in.
940  if (State.isBase() && isa<ExtractElementInst>(I) &&
941  isa<VectorType>(State.getBaseValue()->getType())) {
942  auto *EE = cast<ExtractElementInst>(I);
943  // TODO: In many cases, the new instruction is just EE itself. We should
944  // exploit this, but can't do it here since it would break the invariant
945  // about the BDV not being known to be a base.
946  auto *BaseInst = ExtractElementInst::Create(
947  State.getBaseValue(), EE->getIndexOperand(), "base_ee", EE);
948  BaseInst->setMetadata("is_base_value", MDNode::get(I->getContext(), {}));
949  States[I] = BDVState(BDVState::Base, BaseInst);
950  }
951 
952  // Since we're joining a vector and scalar base, they can never be the
953  // same. As a result, we should always see insert element having reached
954  // the conflict state.
955  assert(!isa<InsertElementInst>(I) || State.isConflict());
956 
957  if (!State.isConflict())
958  continue;
959 
960  /// Create and insert a new instruction which will represent the base of
961  /// the given instruction 'I'.
962  auto MakeBaseInstPlaceholder = [](Instruction *I) -> Instruction* {
963  if (isa<PHINode>(I)) {
964  BasicBlock *BB = I->getParent();
965  int NumPreds = pred_size(BB);
966  assert(NumPreds > 0 && "how did we reach here");
967  std::string Name = suffixed_name_or(I, ".base", "base_phi");
968  return PHINode::Create(I->getType(), NumPreds, Name, I);
969  } else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
970  // The undef will be replaced later
971  UndefValue *Undef = UndefValue::get(SI->getType());
972  std::string Name = suffixed_name_or(I, ".base", "base_select");
973  return SelectInst::Create(SI->getCondition(), Undef, Undef, Name, SI);
974  } else if (auto *EE = dyn_cast<ExtractElementInst>(I)) {
975  UndefValue *Undef = UndefValue::get(EE->getVectorOperand()->getType());
976  std::string Name = suffixed_name_or(I, ".base", "base_ee");
977  return ExtractElementInst::Create(Undef, EE->getIndexOperand(), Name,
978  EE);
979  } else if (auto *IE = dyn_cast<InsertElementInst>(I)) {
980  UndefValue *VecUndef = UndefValue::get(IE->getOperand(0)->getType());
981  UndefValue *ScalarUndef = UndefValue::get(IE->getOperand(1)->getType());
982  std::string Name = suffixed_name_or(I, ".base", "base_ie");
983  return InsertElementInst::Create(VecUndef, ScalarUndef,
984  IE->getOperand(2), Name, IE);
985  } else {
986  auto *SV = cast<ShuffleVectorInst>(I);
987  UndefValue *VecUndef = UndefValue::get(SV->getOperand(0)->getType());
988  std::string Name = suffixed_name_or(I, ".base", "base_sv");
989  return new ShuffleVectorInst(VecUndef, VecUndef, SV->getOperand(2),
990  Name, SV);
991  }
992  };
993  Instruction *BaseInst = MakeBaseInstPlaceholder(I);
994  // Add metadata marking this as a base value
995  BaseInst->setMetadata("is_base_value", MDNode::get(I->getContext(), {}));
996  States[I] = BDVState(BDVState::Conflict, BaseInst);
997  }
998 
999  // Returns a instruction which produces the base pointer for a given
1000  // instruction. The instruction is assumed to be an input to one of the BDVs
1001  // seen in the inference algorithm above. As such, we must either already
1002  // know it's base defining value is a base, or have inserted a new
1003  // instruction to propagate the base of it's BDV and have entered that newly
1004  // introduced instruction into the state table. In either case, we are
1005  // assured to be able to determine an instruction which produces it's base
1006  // pointer.
1007  auto getBaseForInput = [&](Value *Input, Instruction *InsertPt) {
1008  Value *BDV = findBaseOrBDV(Input, Cache);
1009  Value *Base = nullptr;
1010  if (isKnownBaseResult(BDV)) {
1011  Base = BDV;
1012  } else {
1013  // Either conflict or base.
1014  assert(States.count(BDV));
1015  Base = States[BDV].getBaseValue();
1016  }
1017  assert(Base && "Can't be null");
1018  // The cast is needed since base traversal may strip away bitcasts
1019  if (Base->getType() != Input->getType() && InsertPt)
1020  Base = new BitCastInst(Base, Input->getType(), "cast", InsertPt);
1021  return Base;
1022  };
1023 
1024  // Fixup all the inputs of the new PHIs. Visit order needs to be
1025  // deterministic and predictable because we're naming newly created
1026  // instructions.
1027  for (auto Pair : States) {
1028  Instruction *BDV = cast<Instruction>(Pair.first);
1029  BDVState State = Pair.second;
1030 
1031  assert(!isKnownBaseResult(BDV) && "why did it get added?");
1032  assert(!State.isUnknown() && "Optimistic algorithm didn't complete!");
1033  if (!State.isConflict())
1034  continue;
1035 
1036  if (PHINode *BasePHI = dyn_cast<PHINode>(State.getBaseValue())) {
1037  PHINode *PN = cast<PHINode>(BDV);
1038  unsigned NumPHIValues = PN->getNumIncomingValues();
1039  for (unsigned i = 0; i < NumPHIValues; i++) {
1040  Value *InVal = PN->getIncomingValue(i);
1041  BasicBlock *InBB = PN->getIncomingBlock(i);
1042 
1043  // If we've already seen InBB, add the same incoming value
1044  // we added for it earlier. The IR verifier requires phi
1045  // nodes with multiple entries from the same basic block
1046  // to have the same incoming value for each of those
1047  // entries. If we don't do this check here and basephi
1048  // has a different type than base, we'll end up adding two
1049  // bitcasts (and hence two distinct values) as incoming
1050  // values for the same basic block.
1051 
1052  int BlockIndex = BasePHI->getBasicBlockIndex(InBB);
1053  if (BlockIndex != -1) {
1054  Value *OldBase = BasePHI->getIncomingValue(BlockIndex);
1055  BasePHI->addIncoming(OldBase, InBB);
1056 
1057 #ifndef NDEBUG
1058  Value *Base = getBaseForInput(InVal, nullptr);
1059  // In essence this assert states: the only way two values
1060  // incoming from the same basic block may be different is by
1061  // being different bitcasts of the same value. A cleanup
1062  // that remains TODO is changing findBaseOrBDV to return an
1063  // llvm::Value of the correct type (and still remain pure).
1064  // This will remove the need to add bitcasts.
1065  assert(Base->stripPointerCasts() == OldBase->stripPointerCasts() &&
1066  "Sanity -- findBaseOrBDV should be pure!");
1067 #endif
1068  continue;
1069  }
1070 
1071  // Find the instruction which produces the base for each input. We may
1072  // need to insert a bitcast in the incoming block.
1073  // TODO: Need to split critical edges if insertion is needed
1074  Value *Base = getBaseForInput(InVal, InBB->getTerminator());
1075  BasePHI->addIncoming(Base, InBB);
1076  }
1077  assert(BasePHI->getNumIncomingValues() == NumPHIValues);
1078  } else if (SelectInst *BaseSI =
1079  dyn_cast<SelectInst>(State.getBaseValue())) {
1080  SelectInst *SI = cast<SelectInst>(BDV);
1081 
1082  // Find the instruction which produces the base for each input.
1083  // We may need to insert a bitcast.
1084  BaseSI->setTrueValue(getBaseForInput(SI->getTrueValue(), BaseSI));
1085  BaseSI->setFalseValue(getBaseForInput(SI->getFalseValue(), BaseSI));
1086  } else if (auto *BaseEE =
1087  dyn_cast<ExtractElementInst>(State.getBaseValue())) {
1088  Value *InVal = cast<ExtractElementInst>(BDV)->getVectorOperand();
1089  // Find the instruction which produces the base for each input. We may
1090  // need to insert a bitcast.
1091  BaseEE->setOperand(0, getBaseForInput(InVal, BaseEE));
1092  } else if (auto *BaseIE = dyn_cast<InsertElementInst>(State.getBaseValue())){
1093  auto *BdvIE = cast<InsertElementInst>(BDV);
1094  auto UpdateOperand = [&](int OperandIdx) {
1095  Value *InVal = BdvIE->getOperand(OperandIdx);
1096  Value *Base = getBaseForInput(InVal, BaseIE);
1097  BaseIE->setOperand(OperandIdx, Base);
1098  };
1099  UpdateOperand(0); // vector operand
1100  UpdateOperand(1); // scalar operand
1101  } else {
1102  auto *BaseSV = cast<ShuffleVectorInst>(State.getBaseValue());
1103  auto *BdvSV = cast<ShuffleVectorInst>(BDV);
1104  auto UpdateOperand = [&](int OperandIdx) {
1105  Value *InVal = BdvSV->getOperand(OperandIdx);
1106  Value *Base = getBaseForInput(InVal, BaseSV);
1107  BaseSV->setOperand(OperandIdx, Base);
1108  };
1109  UpdateOperand(0); // vector operand
1110  UpdateOperand(1); // vector operand
1111  }
1112  }
1113 
1114  // Cache all of our results so we can cheaply reuse them
1115  // NOTE: This is actually two caches: one of the base defining value
1116  // relation and one of the base pointer relation! FIXME
1117  for (auto Pair : States) {
1118  auto *BDV = Pair.first;
1119  Value *Base = Pair.second.getBaseValue();
1120  assert(BDV && Base);
1121  assert(!isKnownBaseResult(BDV) && "why did it get added?");
1122 
1123  LLVM_DEBUG(
1124  dbgs() << "Updating base value cache"
1125  << " for: " << BDV->getName() << " from: "
1126  << (Cache.count(BDV) ? Cache[BDV]->getName().str() : "none")
1127  << " to: " << Base->getName() << "\n");
1128 
1129  if (Cache.count(BDV)) {
1130  assert(isKnownBaseResult(Base) &&
1131  "must be something we 'know' is a base pointer");
1132  // Once we transition from the BDV relation being store in the Cache to
1133  // the base relation being stored, it must be stable
1134  assert((!isKnownBaseResult(Cache[BDV]) || Cache[BDV] == Base) &&
1135  "base relation should be stable");
1136  }
1137  Cache[BDV] = Base;
1138  }
1139  assert(Cache.count(Def));
1140  return Cache[Def];
1141 }
1142 
1143 // For a set of live pointers (base and/or derived), identify the base
1144 // pointer of the object which they are derived from. This routine will
1145 // mutate the IR graph as needed to make the 'base' pointer live at the
1146 // definition site of 'derived'. This ensures that any use of 'derived' can
1147 // also use 'base'. This may involve the insertion of a number of
1148 // additional PHI nodes.
1149 //
1150 // preconditions: live is a set of pointer type Values
1151 //
1152 // side effects: may insert PHI nodes into the existing CFG, will preserve
1153 // CFG, will not remove or mutate any existing nodes
1154 //
1155 // post condition: PointerToBase contains one (derived, base) pair for every
1156 // pointer in live. Note that derived can be equal to base if the original
1157 // pointer was a base pointer.
1158 static void
1160  MapVector<Value *, Value *> &PointerToBase,
1161  DominatorTree *DT, DefiningValueMapTy &DVCache) {
1162  for (Value *ptr : live) {
1163  Value *base = findBasePointer(ptr, DVCache);
1164  assert(base && "failed to find base pointer");
1165  PointerToBase[ptr] = base;
1166  assert((!isa<Instruction>(base) || !isa<Instruction>(ptr) ||
1167  DT->dominates(cast<Instruction>(base)->getParent(),
1168  cast<Instruction>(ptr)->getParent())) &&
1169  "The base we found better dominate the derived pointer");
1170  }
1171 }
1172 
1173 /// Find the required based pointers (and adjust the live set) for the given
1174 /// parse point.
1176  CallBase *Call,
1177  PartiallyConstructedSafepointRecord &result) {
1178  MapVector<Value *, Value *> PointerToBase;
1179  findBasePointers(result.LiveSet, PointerToBase, &DT, DVCache);
1180 
1181  if (PrintBasePointers) {
1182  errs() << "Base Pairs (w/o Relocation):\n";
1183  for (auto &Pair : PointerToBase) {
1184  errs() << " derived ";
1185  Pair.first->printAsOperand(errs(), false);
1186  errs() << " base ";
1187  Pair.second->printAsOperand(errs(), false);
1188  errs() << "\n";;
1189  }
1190  }
1191 
1192  result.PointerToBase = PointerToBase;
1193 }
1194 
1195 /// Given an updated version of the dataflow liveness results, update the
1196 /// liveset and base pointer maps for the call site CS.
1197 static void recomputeLiveInValues(GCPtrLivenessData &RevisedLivenessData,
1198  CallBase *Call,
1199  PartiallyConstructedSafepointRecord &result);
1200 
1202  Function &F, DominatorTree &DT, ArrayRef<CallBase *> toUpdate,
1204  // TODO-PERF: reuse the original liveness, then simply run the dataflow
1205  // again. The old values are still live and will help it stabilize quickly.
1206  GCPtrLivenessData RevisedLivenessData;
1207  computeLiveInValues(DT, F, RevisedLivenessData);
1208  for (size_t i = 0; i < records.size(); i++) {
1209  struct PartiallyConstructedSafepointRecord &info = records[i];
1210  recomputeLiveInValues(RevisedLivenessData, toUpdate[i], info);
1211  }
1212 }
1213 
1214 // When inserting gc.relocate and gc.result calls, we need to ensure there are
1215 // no uses of the original value / return value between the gc.statepoint and
1216 // the gc.relocate / gc.result call. One case which can arise is a phi node
1217 // starting one of the successor blocks. We also need to be able to insert the
1218 // gc.relocates only on the path which goes through the statepoint. We might
1219 // need to split an edge to make this possible.
1220 static BasicBlock *
1222  DominatorTree &DT) {
1223  BasicBlock *Ret = BB;
1224  if (!BB->getUniquePredecessor())
1225  Ret = SplitBlockPredecessors(BB, InvokeParent, "", &DT);
1226 
1227  // Now that 'Ret' has unique predecessor we can safely remove all phi nodes
1228  // from it
1230  assert(!isa<PHINode>(Ret->begin()) &&
1231  "All PHI nodes should have been removed!");
1232 
1233  // At this point, we can safely insert a gc.relocate or gc.result as the first
1234  // instruction in Ret if needed.
1235  return Ret;
1236 }
1237 
1238 // Create new attribute set containing only attributes which can be transferred
1239 // from original call to the safepoint.
1241  if (AL.isEmpty())
1242  return AL;
1243 
1244  // Remove the readonly, readnone, and statepoint function attributes.
1245  AttrBuilder FnAttrs = AL.getFnAttributes();
1246  FnAttrs.removeAttribute(Attribute::ReadNone);
1247  FnAttrs.removeAttribute(Attribute::ReadOnly);
1248  for (Attribute A : AL.getFnAttributes()) {
1250  FnAttrs.remove(A);
1251  }
1252 
1253  // Just skip parameter and return attributes for now
1254  LLVMContext &Ctx = AL.getContext();
1256  AttributeSet::get(Ctx, FnAttrs));
1257 }
1258 
1259 /// Helper function to place all gc relocates necessary for the given
1260 /// statepoint.
1261 /// Inputs:
1262 /// liveVariables - list of variables to be relocated.
1263 /// liveStart - index of the first live variable.
1264 /// basePtrs - base pointers.
1265 /// statepointToken - statepoint instruction to which relocates should be
1266 /// bound.
1267 /// Builder - Llvm IR builder to be used to construct new calls.
1269  const int LiveStart,
1270  ArrayRef<Value *> BasePtrs,
1271  Instruction *StatepointToken,
1272  IRBuilder<> Builder) {
1273  if (LiveVariables.empty())
1274  return;
1275 
1276  auto FindIndex = [](ArrayRef<Value *> LiveVec, Value *Val) {
1277  auto ValIt = llvm::find(LiveVec, Val);
1278  assert(ValIt != LiveVec.end() && "Val not found in LiveVec!");
1279  size_t Index = std::distance(LiveVec.begin(), ValIt);
1280  assert(Index < LiveVec.size() && "Bug in std::find?");
1281  return Index;
1282  };
1283  Module *M = StatepointToken->getModule();
1284 
1285  // All gc_relocate are generated as i8 addrspace(1)* (or a vector type whose
1286  // element type is i8 addrspace(1)*). We originally generated unique
1287  // declarations for each pointer type, but this proved problematic because
1288  // the intrinsic mangling code is incomplete and fragile. Since we're moving
1289  // towards a single unified pointer type anyways, we can just cast everything
1290  // to an i8* of the right address space. A bitcast is added later to convert
1291  // gc_relocate to the actual value's type.
1292  auto getGCRelocateDecl = [&] (Type *Ty) {
1294  auto AS = Ty->getScalarType()->getPointerAddressSpace();
1295  Type *NewTy = Type::getInt8PtrTy(M->getContext(), AS);
1296  if (auto *VT = dyn_cast<VectorType>(Ty))
1297  NewTy = VectorType::get(NewTy, VT->getNumElements());
1298  return Intrinsic::getDeclaration(M, Intrinsic::experimental_gc_relocate,
1299  {NewTy});
1300  };
1301 
1302  // Lazily populated map from input types to the canonicalized form mentioned
1303  // in the comment above. This should probably be cached somewhere more
1304  // broadly.
1305  DenseMap<Type *, Function *> TypeToDeclMap;
1306 
1307  for (unsigned i = 0; i < LiveVariables.size(); i++) {
1308  // Generate the gc.relocate call and save the result
1309  Value *BaseIdx =
1310  Builder.getInt32(LiveStart + FindIndex(LiveVariables, BasePtrs[i]));
1311  Value *LiveIdx = Builder.getInt32(LiveStart + i);
1312 
1313  Type *Ty = LiveVariables[i]->getType();
1314  if (!TypeToDeclMap.count(Ty))
1315  TypeToDeclMap[Ty] = getGCRelocateDecl(Ty);
1316  Function *GCRelocateDecl = TypeToDeclMap[Ty];
1317 
1318  // only specify a debug name if we can give a useful one
1319  CallInst *Reloc = Builder.CreateCall(
1320  GCRelocateDecl, {StatepointToken, BaseIdx, LiveIdx},
1321  suffixed_name_or(LiveVariables[i], ".relocated", ""));
1322  // Trick CodeGen into thinking there are lots of free registers at this
1323  // fake call.
1325  }
1326 }
1327 
1328 namespace {
1329 
1330 /// This struct is used to defer RAUWs and `eraseFromParent` s. Using this
1331 /// avoids having to worry about keeping around dangling pointers to Values.
1332 class DeferredReplacement {
1335  bool IsDeoptimize = false;
1336 
1337  DeferredReplacement() = default;
1338 
1339 public:
1340  static DeferredReplacement createRAUW(Instruction *Old, Instruction *New) {
1341  assert(Old != New && Old && New &&
1342  "Cannot RAUW equal values or to / from null!");
1343 
1344  DeferredReplacement D;
1345  D.Old = Old;
1346  D.New = New;
1347  return D;
1348  }
1349 
1350  static DeferredReplacement createDelete(Instruction *ToErase) {
1351  DeferredReplacement D;
1352  D.Old = ToErase;
1353  return D;
1354  }
1355 
1356  static DeferredReplacement createDeoptimizeReplacement(Instruction *Old) {
1357 #ifndef NDEBUG
1358  auto *F = cast<CallInst>(Old)->getCalledFunction();
1359  assert(F && F->getIntrinsicID() == Intrinsic::experimental_deoptimize &&
1360  "Only way to construct a deoptimize deferred replacement");
1361 #endif
1362  DeferredReplacement D;
1363  D.Old = Old;
1364  D.IsDeoptimize = true;
1365  return D;
1366  }
1367 
1368  /// Does the task represented by this instance.
1369  void doReplacement() {
1370  Instruction *OldI = Old;
1371  Instruction *NewI = New;
1372 
1373  assert(OldI != NewI && "Disallowed at construction?!");
1374  assert((!IsDeoptimize || !New) &&
1375  "Deoptimize intrinsics are not replaced!");
1376 
1377  Old = nullptr;
1378  New = nullptr;
1379 
1380  if (NewI)
1381  OldI->replaceAllUsesWith(NewI);
1382 
1383  if (IsDeoptimize) {
1384  // Note: we've inserted instructions, so the call to llvm.deoptimize may
1385  // not necessarily be followed by the matching return.
1386  auto *RI = cast<ReturnInst>(OldI->getParent()->getTerminator());
1387  new UnreachableInst(RI->getContext(), RI);
1388  RI->eraseFromParent();
1389  }
1390 
1391  OldI->eraseFromParent();
1392  }
1393 };
1394 
1395 } // end anonymous namespace
1396 
1398  const char *DeoptLowering = "deopt-lowering";
1399  if (Call->hasFnAttr(DeoptLowering)) {
1400  // FIXME: Calls have a *really* confusing interface around attributes
1401  // with values.
1402  const AttributeList &CSAS = Call->getAttributes();
1403  if (CSAS.hasAttribute(AttributeList::FunctionIndex, DeoptLowering))
1404  return CSAS.getAttribute(AttributeList::FunctionIndex, DeoptLowering)
1405  .getValueAsString();
1406  Function *F = Call->getCalledFunction();
1407  assert(F && F->hasFnAttribute(DeoptLowering));
1408  return F->getFnAttribute(DeoptLowering).getValueAsString();
1409  }
1410  return "live-through";
1411 }
1412 
1413 static void
1414 makeStatepointExplicitImpl(CallBase *Call, /* to replace */
1415  const SmallVectorImpl<Value *> &BasePtrs,
1417  PartiallyConstructedSafepointRecord &Result,
1418  std::vector<DeferredReplacement> &Replacements) {
1419  assert(BasePtrs.size() == LiveVariables.size());
1420 
1421  // Then go ahead and use the builder do actually do the inserts. We insert
1422  // immediately before the previous instruction under the assumption that all
1423  // arguments will be available here. We can't insert afterwards since we may
1424  // be replacing a terminator.
1425  IRBuilder<> Builder(Call);
1426 
1427  ArrayRef<Value *> GCArgs(LiveVariables);
1428  uint64_t StatepointID = StatepointDirectives::DefaultStatepointID;
1429  uint32_t NumPatchBytes = 0;
1431 
1432  ArrayRef<Use> CallArgs(Call->arg_begin(), Call->arg_end());
1433  ArrayRef<Use> DeoptArgs = GetDeoptBundleOperands(Call);
1434  ArrayRef<Use> TransitionArgs;
1435  if (auto TransitionBundle =
1438  TransitionArgs = TransitionBundle->Inputs;
1439  }
1440 
1441  // Instead of lowering calls to @llvm.experimental.deoptimize as normal calls
1442  // with a return value, we lower then as never returning calls to
1443  // __llvm_deoptimize that are followed by unreachable to get better codegen.
1444  bool IsDeoptimize = false;
1445 
1448  if (SD.NumPatchBytes)
1449  NumPatchBytes = *SD.NumPatchBytes;
1450  if (SD.StatepointID)
1451  StatepointID = *SD.StatepointID;
1452 
1453  // Pass through the requested lowering if any. The default is live-through.
1454  StringRef DeoptLowering = getDeoptLowering(Call);
1455  if (DeoptLowering.equals("live-in"))
1457  else {
1458  assert(DeoptLowering.equals("live-through") && "Unsupported value!");
1459  }
1460 
1461  Value *CallTarget = Call->getCalledValue();
1462  if (Function *F = dyn_cast<Function>(CallTarget)) {
1463  if (F->getIntrinsicID() == Intrinsic::experimental_deoptimize) {
1464  // Calls to llvm.experimental.deoptimize are lowered to calls to the
1465  // __llvm_deoptimize symbol. We want to resolve this now, since the
1466  // verifier does not allow taking the address of an intrinsic function.
1467 
1468  SmallVector<Type *, 8> DomainTy;
1469  for (Value *Arg : CallArgs)
1470  DomainTy.push_back(Arg->getType());
1471  auto *FTy = FunctionType::get(Type::getVoidTy(F->getContext()), DomainTy,
1472  /* isVarArg = */ false);
1473 
1474  // Note: CallTarget can be a bitcast instruction of a symbol if there are
1475  // calls to @llvm.experimental.deoptimize with different argument types in
1476  // the same module. This is fine -- we assume the frontend knew what it
1477  // was doing when generating this kind of IR.
1478  CallTarget = F->getParent()
1479  ->getOrInsertFunction("__llvm_deoptimize", FTy)
1480  .getCallee();
1481 
1482  IsDeoptimize = true;
1483  }
1484  }
1485 
1486  // Create the statepoint given all the arguments
1487  Instruction *Token = nullptr;
1488  if (auto *CI = dyn_cast<CallInst>(Call)) {
1489  CallInst *SPCall = Builder.CreateGCStatepointCall(
1490  StatepointID, NumPatchBytes, CallTarget, Flags, CallArgs,
1491  TransitionArgs, DeoptArgs, GCArgs, "safepoint_token");
1492 
1493  SPCall->setTailCallKind(CI->getTailCallKind());
1494  SPCall->setCallingConv(CI->getCallingConv());
1495 
1496  // Currently we will fail on parameter attributes and on certain
1497  // function attributes. In case if we can handle this set of attributes -
1498  // set up function attrs directly on statepoint and return attrs later for
1499  // gc_result intrinsic.
1500  SPCall->setAttributes(legalizeCallAttributes(CI->getAttributes()));
1501 
1502  Token = SPCall;
1503 
1504  // Put the following gc_result and gc_relocate calls immediately after the
1505  // the old call (which we're about to delete)
1506  assert(CI->getNextNode() && "Not a terminator, must have next!");
1507  Builder.SetInsertPoint(CI->getNextNode());
1508  Builder.SetCurrentDebugLocation(CI->getNextNode()->getDebugLoc());
1509  } else {
1510  auto *II = cast<InvokeInst>(Call);
1511 
1512  // Insert the new invoke into the old block. We'll remove the old one in a
1513  // moment at which point this will become the new terminator for the
1514  // original block.
1515  InvokeInst *SPInvoke = Builder.CreateGCStatepointInvoke(
1516  StatepointID, NumPatchBytes, CallTarget, II->getNormalDest(),
1517  II->getUnwindDest(), Flags, CallArgs, TransitionArgs, DeoptArgs, GCArgs,
1518  "statepoint_token");
1519 
1520  SPInvoke->setCallingConv(II->getCallingConv());
1521 
1522  // Currently we will fail on parameter attributes and on certain
1523  // function attributes. In case if we can handle this set of attributes -
1524  // set up function attrs directly on statepoint and return attrs later for
1525  // gc_result intrinsic.
1526  SPInvoke->setAttributes(legalizeCallAttributes(II->getAttributes()));
1527 
1528  Token = SPInvoke;
1529 
1530  // Generate gc relocates in exceptional path
1531  BasicBlock *UnwindBlock = II->getUnwindDest();
1532  assert(!isa<PHINode>(UnwindBlock->begin()) &&
1533  UnwindBlock->getUniquePredecessor() &&
1534  "can't safely insert in this block!");
1535 
1536  Builder.SetInsertPoint(&*UnwindBlock->getFirstInsertionPt());
1537  Builder.SetCurrentDebugLocation(II->getDebugLoc());
1538 
1539  // Attach exceptional gc relocates to the landingpad.
1540  Instruction *ExceptionalToken = UnwindBlock->getLandingPadInst();
1541  Result.UnwindToken = ExceptionalToken;
1542 
1543  const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
1544  CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, ExceptionalToken,
1545  Builder);
1546 
1547  // Generate gc relocates and returns for normal block
1548  BasicBlock *NormalDest = II->getNormalDest();
1549  assert(!isa<PHINode>(NormalDest->begin()) &&
1550  NormalDest->getUniquePredecessor() &&
1551  "can't safely insert in this block!");
1552 
1553  Builder.SetInsertPoint(&*NormalDest->getFirstInsertionPt());
1554 
1555  // gc relocates will be generated later as if it were regular call
1556  // statepoint
1557  }
1558  assert(Token && "Should be set in one of the above branches!");
1559 
1560  if (IsDeoptimize) {
1561  // If we're wrapping an @llvm.experimental.deoptimize in a statepoint, we
1562  // transform the tail-call like structure to a call to a void function
1563  // followed by unreachable to get better codegen.
1564  Replacements.push_back(
1565  DeferredReplacement::createDeoptimizeReplacement(Call));
1566  } else {
1567  Token->setName("statepoint_token");
1568  if (!Call->getType()->isVoidTy() && !Call->use_empty()) {
1569  StringRef Name = Call->hasName() ? Call->getName() : "";
1570  CallInst *GCResult = Builder.CreateGCResult(Token, Call->getType(), Name);
1571  GCResult->setAttributes(
1573  Call->getAttributes().getRetAttributes()));
1574 
1575  // We cannot RAUW or delete CS.getInstruction() because it could be in the
1576  // live set of some other safepoint, in which case that safepoint's
1577  // PartiallyConstructedSafepointRecord will hold a raw pointer to this
1578  // llvm::Instruction. Instead, we defer the replacement and deletion to
1579  // after the live sets have been made explicit in the IR, and we no longer
1580  // have raw pointers to worry about.
1581  Replacements.emplace_back(
1582  DeferredReplacement::createRAUW(Call, GCResult));
1583  } else {
1584  Replacements.emplace_back(DeferredReplacement::createDelete(Call));
1585  }
1586  }
1587 
1588  Result.StatepointToken = Token;
1589 
1590  // Second, create a gc.relocate for every live variable
1591  const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
1592  CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, Token, Builder);
1593 }
1594 
1595 // Replace an existing gc.statepoint with a new one and a set of gc.relocates
1596 // which make the relocations happening at this safepoint explicit.
1597 //
1598 // WARNING: Does not do any fixup to adjust users of the original live
1599 // values. That's the callers responsibility.
1600 static void
1602  PartiallyConstructedSafepointRecord &Result,
1603  std::vector<DeferredReplacement> &Replacements) {
1604  const auto &LiveSet = Result.LiveSet;
1605  const auto &PointerToBase = Result.PointerToBase;
1606 
1607  // Convert to vector for efficient cross referencing.
1608  SmallVector<Value *, 64> BaseVec, LiveVec;
1609  LiveVec.reserve(LiveSet.size());
1610  BaseVec.reserve(LiveSet.size());
1611  for (Value *L : LiveSet) {
1612  LiveVec.push_back(L);
1613  assert(PointerToBase.count(L));
1614  Value *Base = PointerToBase.find(L)->second;
1615  BaseVec.push_back(Base);
1616  }
1617  assert(LiveVec.size() == BaseVec.size());
1618 
1619  // Do the actual rewriting and delete the old statepoint
1620  makeStatepointExplicitImpl(Call, BaseVec, LiveVec, Result, Replacements);
1621 }
1622 
1623 // Helper function for the relocationViaAlloca.
1624 //
1625 // It receives iterator to the statepoint gc relocates and emits a store to the
1626 // assigned location (via allocaMap) for the each one of them. It adds the
1627 // visited values into the visitedLiveValues set, which we will later use them
1628 // for sanity checking.
1629 static void
1632  DenseSet<Value *> &VisitedLiveValues) {
1633  for (User *U : GCRelocs) {
1634  GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U);
1635  if (!Relocate)
1636  continue;
1637 
1638  Value *OriginalValue = Relocate->getDerivedPtr();
1639  assert(AllocaMap.count(OriginalValue));
1640  Value *Alloca = AllocaMap[OriginalValue];
1641 
1642  // Emit store into the related alloca
1643  // All gc_relocates are i8 addrspace(1)* typed, and it must be bitcasted to
1644  // the correct type according to alloca.
1645  assert(Relocate->getNextNode() &&
1646  "Should always have one since it's not a terminator");
1647  IRBuilder<> Builder(Relocate->getNextNode());
1648  Value *CastedRelocatedValue =
1649  Builder.CreateBitCast(Relocate,
1650  cast<AllocaInst>(Alloca)->getAllocatedType(),
1651  suffixed_name_or(Relocate, ".casted", ""));
1652 
1653  StoreInst *Store = new StoreInst(CastedRelocatedValue, Alloca);
1654  Store->insertAfter(cast<Instruction>(CastedRelocatedValue));
1655 
1656 #ifndef NDEBUG
1657  VisitedLiveValues.insert(OriginalValue);
1658 #endif
1659  }
1660 }
1661 
1662 // Helper function for the "relocationViaAlloca". Similar to the
1663 // "insertRelocationStores" but works for rematerialized values.
1665  const RematerializedValueMapTy &RematerializedValues,
1667  DenseSet<Value *> &VisitedLiveValues) {
1668  for (auto RematerializedValuePair: RematerializedValues) {
1669  Instruction *RematerializedValue = RematerializedValuePair.first;
1670  Value *OriginalValue = RematerializedValuePair.second;
1671 
1672  assert(AllocaMap.count(OriginalValue) &&
1673  "Can not find alloca for rematerialized value");
1674  Value *Alloca = AllocaMap[OriginalValue];
1675 
1676  StoreInst *Store = new StoreInst(RematerializedValue, Alloca);
1677  Store->insertAfter(RematerializedValue);
1678 
1679 #ifndef NDEBUG
1680  VisitedLiveValues.insert(OriginalValue);
1681 #endif
1682  }
1683 }
1684 
1685 /// Do all the relocation update via allocas and mem2reg
1689 #ifndef NDEBUG
1690  // record initial number of (static) allocas; we'll check we have the same
1691  // number when we get done.
1692  int InitialAllocaNum = 0;
1693  for (Instruction &I : F.getEntryBlock())
1694  if (isa<AllocaInst>(I))
1695  InitialAllocaNum++;
1696 #endif
1697 
1698  // TODO-PERF: change data structures, reserve
1700  SmallVector<AllocaInst *, 200> PromotableAllocas;
1701  // Used later to chack that we have enough allocas to store all values
1702  std::size_t NumRematerializedValues = 0;
1703  PromotableAllocas.reserve(Live.size());
1704 
1705  // Emit alloca for "LiveValue" and record it in "allocaMap" and
1706  // "PromotableAllocas"
1707  const DataLayout &DL = F.getParent()->getDataLayout();
1708  auto emitAllocaFor = [&](Value *LiveValue) {
1709  AllocaInst *Alloca = new AllocaInst(LiveValue->getType(),
1710  DL.getAllocaAddrSpace(), "",
1712  AllocaMap[LiveValue] = Alloca;
1713  PromotableAllocas.push_back(Alloca);
1714  };
1715 
1716  // Emit alloca for each live gc pointer
1717  for (Value *V : Live)
1718  emitAllocaFor(V);
1719 
1720  // Emit allocas for rematerialized values
1721  for (const auto &Info : Records)
1722  for (auto RematerializedValuePair : Info.RematerializedValues) {
1723  Value *OriginalValue = RematerializedValuePair.second;
1724  if (AllocaMap.count(OriginalValue) != 0)
1725  continue;
1726 
1727  emitAllocaFor(OriginalValue);
1728  ++NumRematerializedValues;
1729  }
1730 
1731  // The next two loops are part of the same conceptual operation. We need to
1732  // insert a store to the alloca after the original def and at each
1733  // redefinition. We need to insert a load before each use. These are split
1734  // into distinct loops for performance reasons.
1735 
1736  // Update gc pointer after each statepoint: either store a relocated value or
1737  // null (if no relocated value was found for this gc pointer and it is not a
1738  // gc_result). This must happen before we update the statepoint with load of
1739  // alloca otherwise we lose the link between statepoint and old def.
1740  for (const auto &Info : Records) {
1741  Value *Statepoint = Info.StatepointToken;
1742 
1743  // This will be used for consistency check
1744  DenseSet<Value *> VisitedLiveValues;
1745 
1746  // Insert stores for normal statepoint gc relocates
1747  insertRelocationStores(Statepoint->users(), AllocaMap, VisitedLiveValues);
1748 
1749  // In case if it was invoke statepoint
1750  // we will insert stores for exceptional path gc relocates.
1751  if (isa<InvokeInst>(Statepoint)) {
1752  insertRelocationStores(Info.UnwindToken->users(), AllocaMap,
1753  VisitedLiveValues);
1754  }
1755 
1756  // Do similar thing with rematerialized values
1757  insertRematerializationStores(Info.RematerializedValues, AllocaMap,
1758  VisitedLiveValues);
1759 
1760  if (ClobberNonLive) {
1761  // As a debugging aid, pretend that an unrelocated pointer becomes null at
1762  // the gc.statepoint. This will turn some subtle GC problems into
1763  // slightly easier to debug SEGVs. Note that on large IR files with
1764  // lots of gc.statepoints this is extremely costly both memory and time
1765  // wise.
1767  for (auto Pair : AllocaMap) {
1768  Value *Def = Pair.first;
1769  AllocaInst *Alloca = Pair.second;
1770 
1771  // This value was relocated
1772  if (VisitedLiveValues.count(Def)) {
1773  continue;
1774  }
1775  ToClobber.push_back(Alloca);
1776  }
1777 
1778  auto InsertClobbersAt = [&](Instruction *IP) {
1779  for (auto *AI : ToClobber) {
1780  auto PT = cast<PointerType>(AI->getAllocatedType());
1782  StoreInst *Store = new StoreInst(CPN, AI);
1783  Store->insertBefore(IP);
1784  }
1785  };
1786 
1787  // Insert the clobbering stores. These may get intermixed with the
1788  // gc.results and gc.relocates, but that's fine.
1789  if (auto II = dyn_cast<InvokeInst>(Statepoint)) {
1790  InsertClobbersAt(&*II->getNormalDest()->getFirstInsertionPt());
1791  InsertClobbersAt(&*II->getUnwindDest()->getFirstInsertionPt());
1792  } else {
1793  InsertClobbersAt(cast<Instruction>(Statepoint)->getNextNode());
1794  }
1795  }
1796  }
1797 
1798  // Update use with load allocas and add store for gc_relocated.
1799  for (auto Pair : AllocaMap) {
1800  Value *Def = Pair.first;
1801  AllocaInst *Alloca = Pair.second;
1802 
1803  // We pre-record the uses of allocas so that we dont have to worry about
1804  // later update that changes the user information..
1805 
1807  // PERF: trade a linear scan for repeated reallocation
1808  Uses.reserve(Def->getNumUses());
1809  for (User *U : Def->users()) {
1810  if (!isa<ConstantExpr>(U)) {
1811  // If the def has a ConstantExpr use, then the def is either a
1812  // ConstantExpr use itself or null. In either case
1813  // (recursively in the first, directly in the second), the oop
1814  // it is ultimately dependent on is null and this particular
1815  // use does not need to be fixed up.
1816  Uses.push_back(cast<Instruction>(U));
1817  }
1818  }
1819 
1820  llvm::sort(Uses);
1821  auto Last = std::unique(Uses.begin(), Uses.end());
1822  Uses.erase(Last, Uses.end());
1823 
1824  for (Instruction *Use : Uses) {
1825  if (isa<PHINode>(Use)) {
1826  PHINode *Phi = cast<PHINode>(Use);
1827  for (unsigned i = 0; i < Phi->getNumIncomingValues(); i++) {
1828  if (Def == Phi->getIncomingValue(i)) {
1829  LoadInst *Load =
1830  new LoadInst(Alloca->getAllocatedType(), Alloca, "",
1831  Phi->getIncomingBlock(i)->getTerminator());
1832  Phi->setIncomingValue(i, Load);
1833  }
1834  }
1835  } else {
1836  LoadInst *Load =
1837  new LoadInst(Alloca->getAllocatedType(), Alloca, "", Use);
1838  Use->replaceUsesOfWith(Def, Load);
1839  }
1840  }
1841 
1842  // Emit store for the initial gc value. Store must be inserted after load,
1843  // otherwise store will be in alloca's use list and an extra load will be
1844  // inserted before it.
1845  StoreInst *Store = new StoreInst(Def, Alloca);
1846  if (Instruction *Inst = dyn_cast<Instruction>(Def)) {
1847  if (InvokeInst *Invoke = dyn_cast<InvokeInst>(Inst)) {
1848  // InvokeInst is a terminator so the store need to be inserted into its
1849  // normal destination block.
1850  BasicBlock *NormalDest = Invoke->getNormalDest();
1851  Store->insertBefore(NormalDest->getFirstNonPHI());
1852  } else {
1853  assert(!Inst->isTerminator() &&
1854  "The only terminator that can produce a value is "
1855  "InvokeInst which is handled above.");
1856  Store->insertAfter(Inst);
1857  }
1858  } else {
1859  assert(isa<Argument>(Def));
1860  Store->insertAfter(cast<Instruction>(Alloca));
1861  }
1862  }
1863 
1864  assert(PromotableAllocas.size() == Live.size() + NumRematerializedValues &&
1865  "we must have the same allocas with lives");
1866  if (!PromotableAllocas.empty()) {
1867  // Apply mem2reg to promote alloca to SSA
1868  PromoteMemToReg(PromotableAllocas, DT);
1869  }
1870 
1871 #ifndef NDEBUG
1872  for (auto &I : F.getEntryBlock())
1873  if (isa<AllocaInst>(I))
1874  InitialAllocaNum--;
1875  assert(InitialAllocaNum == 0 && "We must not introduce any extra allocas");
1876 #endif
1877 }
1878 
1879 /// Implement a unique function which doesn't require we sort the input
1880 /// vector. Doing so has the effect of changing the output of a couple of
1881 /// tests in ways which make them less useful in testing fused safepoints.
1882 template <typename T> static void unique_unsorted(SmallVectorImpl<T> &Vec) {
1883  SmallSet<T, 8> Seen;
1884  Vec.erase(remove_if(Vec, [&](const T &V) { return !Seen.insert(V).second; }),
1885  Vec.end());
1886 }
1887 
1888 /// Insert holders so that each Value is obviously live through the entire
1889 /// lifetime of the call.
1890 static void insertUseHolderAfter(CallBase *Call, const ArrayRef<Value *> Values,
1891  SmallVectorImpl<CallInst *> &Holders) {
1892  if (Values.empty())
1893  // No values to hold live, might as well not insert the empty holder
1894  return;
1895 
1896  Module *M = Call->getModule();
1897  // Use a dummy vararg function to actually hold the values live
1899  "__tmp_use", FunctionType::get(Type::getVoidTy(M->getContext()), true));
1900  if (isa<CallInst>(Call)) {
1901  // For call safepoints insert dummy calls right after safepoint
1902  Holders.push_back(
1903  CallInst::Create(Func, Values, "", &*++Call->getIterator()));
1904  return;
1905  }
1906  // For invoke safepooints insert dummy calls both in normal and
1907  // exceptional destination blocks
1908  auto *II = cast<InvokeInst>(Call);
1909  Holders.push_back(CallInst::Create(
1910  Func, Values, "", &*II->getNormalDest()->getFirstInsertionPt()));
1911  Holders.push_back(CallInst::Create(
1912  Func, Values, "", &*II->getUnwindDest()->getFirstInsertionPt()));
1913 }
1914 
1916  Function &F, DominatorTree &DT, ArrayRef<CallBase *> toUpdate,
1918  GCPtrLivenessData OriginalLivenessData;
1919  computeLiveInValues(DT, F, OriginalLivenessData);
1920  for (size_t i = 0; i < records.size(); i++) {
1921  struct PartiallyConstructedSafepointRecord &info = records[i];
1922  analyzeParsePointLiveness(DT, OriginalLivenessData, toUpdate[i], info);
1923  }
1924 }
1925 
1926 // Helper function for the "rematerializeLiveValues". It walks use chain
1927 // starting from the "CurrentValue" until it reaches the root of the chain, i.e.
1928 // the base or a value it cannot process. Only "simple" values are processed
1929 // (currently it is GEP's and casts). The returned root is examined by the
1930 // callers of findRematerializableChainToBasePointer. Fills "ChainToBase" array
1931 // with all visited values.
1933  SmallVectorImpl<Instruction*> &ChainToBase,
1934  Value *CurrentValue) {
1935  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(CurrentValue)) {
1936  ChainToBase.push_back(GEP);
1937  return findRematerializableChainToBasePointer(ChainToBase,
1938  GEP->getPointerOperand());
1939  }
1940 
1941  if (CastInst *CI = dyn_cast<CastInst>(CurrentValue)) {
1942  if (!CI->isNoopCast(CI->getModule()->getDataLayout()))
1943  return CI;
1944 
1945  ChainToBase.push_back(CI);
1946  return findRematerializableChainToBasePointer(ChainToBase,
1947  CI->getOperand(0));
1948  }
1949 
1950  // We have reached the root of the chain, which is either equal to the base or
1951  // is the first unsupported value along the use chain.
1952  return CurrentValue;
1953 }
1954 
1955 // Helper function for the "rematerializeLiveValues". Compute cost of the use
1956 // chain we are going to rematerialize.
1957 static unsigned
1959  TargetTransformInfo &TTI) {
1960  unsigned Cost = 0;
1961 
1962  for (Instruction *Instr : Chain) {
1963  if (CastInst *CI = dyn_cast<CastInst>(Instr)) {
1964  assert(CI->isNoopCast(CI->getModule()->getDataLayout()) &&
1965  "non noop cast is found during rematerialization");
1966 
1967  Type *SrcTy = CI->getOperand(0)->getType();
1968  Cost += TTI.getCastInstrCost(CI->getOpcode(), CI->getType(), SrcTy, CI);
1969 
1970  } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Instr)) {
1971  // Cost of the address calculation
1972  Type *ValTy = GEP->getSourceElementType();
1973  Cost += TTI.getAddressComputationCost(ValTy);
1974 
1975  // And cost of the GEP itself
1976  // TODO: Use TTI->getGEPCost here (it exists, but appears to be not
1977  // allowed for the external usage)
1978  if (!GEP->hasAllConstantIndices())
1979  Cost += 2;
1980 
1981  } else {
1982  llvm_unreachable("unsupported instruction type during rematerialization");
1983  }
1984  }
1985 
1986  return Cost;
1987 }
1988 
1989 static bool AreEquivalentPhiNodes(PHINode &OrigRootPhi, PHINode &AlternateRootPhi) {
1990  unsigned PhiNum = OrigRootPhi.getNumIncomingValues();
1991  if (PhiNum != AlternateRootPhi.getNumIncomingValues() ||
1992  OrigRootPhi.getParent() != AlternateRootPhi.getParent())
1993  return false;
1994  // Map of incoming values and their corresponding basic blocks of
1995  // OrigRootPhi.
1996  SmallDenseMap<Value *, BasicBlock *, 8> CurrentIncomingValues;
1997  for (unsigned i = 0; i < PhiNum; i++)
1998  CurrentIncomingValues[OrigRootPhi.getIncomingValue(i)] =
1999  OrigRootPhi.getIncomingBlock(i);
2000 
2001  // Both current and base PHIs should have same incoming values and
2002  // the same basic blocks corresponding to the incoming values.
2003  for (unsigned i = 0; i < PhiNum; i++) {
2004  auto CIVI =
2005  CurrentIncomingValues.find(AlternateRootPhi.getIncomingValue(i));
2006  if (CIVI == CurrentIncomingValues.end())
2007  return false;
2008  BasicBlock *CurrentIncomingBB = CIVI->second;
2009  if (CurrentIncomingBB != AlternateRootPhi.getIncomingBlock(i))
2010  return false;
2011  }
2012  return true;
2013 }
2014 
2015 // From the statepoint live set pick values that are cheaper to recompute then
2016 // to relocate. Remove this values from the live set, rematerialize them after
2017 // statepoint and record them in "Info" structure. Note that similar to
2018 // relocated values we don't do any user adjustments here.
2020  PartiallyConstructedSafepointRecord &Info,
2021  TargetTransformInfo &TTI) {
2022  const unsigned int ChainLengthThreshold = 10;
2023 
2024  // Record values we are going to delete from this statepoint live set.
2025  // We can not di this in following loop due to iterator invalidation.
2026  SmallVector<Value *, 32> LiveValuesToBeDeleted;
2027 
2028  for (Value *LiveValue: Info.LiveSet) {
2029  // For each live pointer find its defining chain
2030  SmallVector<Instruction *, 3> ChainToBase;
2031  assert(Info.PointerToBase.count(LiveValue));
2032  Value *RootOfChain =
2034  LiveValue);
2035 
2036  // Nothing to do, or chain is too long
2037  if ( ChainToBase.size() == 0 ||
2038  ChainToBase.size() > ChainLengthThreshold)
2039  continue;
2040 
2041  // Handle the scenario where the RootOfChain is not equal to the
2042  // Base Value, but they are essentially the same phi values.
2043  if (RootOfChain != Info.PointerToBase[LiveValue]) {
2044  PHINode *OrigRootPhi = dyn_cast<PHINode>(RootOfChain);
2045  PHINode *AlternateRootPhi = dyn_cast<PHINode>(Info.PointerToBase[LiveValue]);
2046  if (!OrigRootPhi || !AlternateRootPhi)
2047  continue;
2048  // PHI nodes that have the same incoming values, and belonging to the same
2049  // basic blocks are essentially the same SSA value. When the original phi
2050  // has incoming values with different base pointers, the original phi is
2051  // marked as conflict, and an additional `AlternateRootPhi` with the same
2052  // incoming values get generated by the findBasePointer function. We need
2053  // to identify the newly generated AlternateRootPhi (.base version of phi)
2054  // and RootOfChain (the original phi node itself) are the same, so that we
2055  // can rematerialize the gep and casts. This is a workaround for the
2056  // deficiency in the findBasePointer algorithm.
2057  if (!AreEquivalentPhiNodes(*OrigRootPhi, *AlternateRootPhi))
2058  continue;
2059  // Now that the phi nodes are proved to be the same, assert that
2060  // findBasePointer's newly generated AlternateRootPhi is present in the
2061  // liveset of the call.
2062  assert(Info.LiveSet.count(AlternateRootPhi));
2063  }
2064  // Compute cost of this chain
2065  unsigned Cost = chainToBasePointerCost(ChainToBase, TTI);
2066  // TODO: We can also account for cases when we will be able to remove some
2067  // of the rematerialized values by later optimization passes. I.e if
2068  // we rematerialized several intersecting chains. Or if original values
2069  // don't have any uses besides this statepoint.
2070 
2071  // For invokes we need to rematerialize each chain twice - for normal and
2072  // for unwind basic blocks. Model this by multiplying cost by two.
2073  if (isa<InvokeInst>(Call)) {
2074  Cost *= 2;
2075  }
2076  // If it's too expensive - skip it
2077  if (Cost >= RematerializationThreshold)
2078  continue;
2079 
2080  // Remove value from the live set
2081  LiveValuesToBeDeleted.push_back(LiveValue);
2082 
2083  // Clone instructions and record them inside "Info" structure
2084 
2085  // Walk backwards to visit top-most instructions first
2086  std::reverse(ChainToBase.begin(), ChainToBase.end());
2087 
2088  // Utility function which clones all instructions from "ChainToBase"
2089  // and inserts them before "InsertBefore". Returns rematerialized value
2090  // which should be used after statepoint.
2091  auto rematerializeChain = [&ChainToBase](
2092  Instruction *InsertBefore, Value *RootOfChain, Value *AlternateLiveBase) {
2093  Instruction *LastClonedValue = nullptr;
2094  Instruction *LastValue = nullptr;
2095  for (Instruction *Instr: ChainToBase) {
2096  // Only GEP's and casts are supported as we need to be careful to not
2097  // introduce any new uses of pointers not in the liveset.
2098  // Note that it's fine to introduce new uses of pointers which were
2099  // otherwise not used after this statepoint.
2100  assert(isa<GetElementPtrInst>(Instr) || isa<CastInst>(Instr));
2101 
2102  Instruction *ClonedValue = Instr->clone();
2103  ClonedValue->insertBefore(InsertBefore);
2104  ClonedValue->setName(Instr->getName() + ".remat");
2105 
2106  // If it is not first instruction in the chain then it uses previously
2107  // cloned value. We should update it to use cloned value.
2108  if (LastClonedValue) {
2109  assert(LastValue);
2110  ClonedValue->replaceUsesOfWith(LastValue, LastClonedValue);
2111 #ifndef NDEBUG
2112  for (auto OpValue : ClonedValue->operand_values()) {
2113  // Assert that cloned instruction does not use any instructions from
2114  // this chain other than LastClonedValue
2115  assert(!is_contained(ChainToBase, OpValue) &&
2116  "incorrect use in rematerialization chain");
2117  // Assert that the cloned instruction does not use the RootOfChain
2118  // or the AlternateLiveBase.
2119  assert(OpValue != RootOfChain && OpValue != AlternateLiveBase);
2120  }
2121 #endif
2122  } else {
2123  // For the first instruction, replace the use of unrelocated base i.e.
2124  // RootOfChain/OrigRootPhi, with the corresponding PHI present in the
2125  // live set. They have been proved to be the same PHI nodes. Note
2126  // that the *only* use of the RootOfChain in the ChainToBase list is
2127  // the first Value in the list.
2128  if (RootOfChain != AlternateLiveBase)
2129  ClonedValue->replaceUsesOfWith(RootOfChain, AlternateLiveBase);
2130  }
2131 
2132  LastClonedValue = ClonedValue;
2133  LastValue = Instr;
2134  }
2135  assert(LastClonedValue);
2136  return LastClonedValue;
2137  };
2138 
2139  // Different cases for calls and invokes. For invokes we need to clone
2140  // instructions both on normal and unwind path.
2141  if (isa<CallInst>(Call)) {
2142  Instruction *InsertBefore = Call->getNextNode();
2143  assert(InsertBefore);
2144  Instruction *RematerializedValue = rematerializeChain(
2145  InsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2146  Info.RematerializedValues[RematerializedValue] = LiveValue;
2147  } else {
2148  auto *Invoke = cast<InvokeInst>(Call);
2149 
2150  Instruction *NormalInsertBefore =
2151  &*Invoke->getNormalDest()->getFirstInsertionPt();
2152  Instruction *UnwindInsertBefore =
2153  &*Invoke->getUnwindDest()->getFirstInsertionPt();
2154 
2155  Instruction *NormalRematerializedValue = rematerializeChain(
2156  NormalInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2157  Instruction *UnwindRematerializedValue = rematerializeChain(
2158  UnwindInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2159 
2160  Info.RematerializedValues[NormalRematerializedValue] = LiveValue;
2161  Info.RematerializedValues[UnwindRematerializedValue] = LiveValue;
2162  }
2163  }
2164 
2165  // Remove rematerializaed values from the live set
2166  for (auto LiveValue: LiveValuesToBeDeleted) {
2167  Info.LiveSet.remove(LiveValue);
2168  }
2169 }
2170 
2172  TargetTransformInfo &TTI,
2173  SmallVectorImpl<CallBase *> &ToUpdate) {
2174 #ifndef NDEBUG
2175  // sanity check the input
2176  std::set<CallBase *> Uniqued;
2177  Uniqued.insert(ToUpdate.begin(), ToUpdate.end());
2178  assert(Uniqued.size() == ToUpdate.size() && "no duplicates please!");
2179 
2180  for (CallBase *Call : ToUpdate)
2181  assert(Call->getFunction() == &F);
2182 #endif
2183 
2184  // When inserting gc.relocates for invokes, we need to be able to insert at
2185  // the top of the successor blocks. See the comment on
2186  // normalForInvokeSafepoint on exactly what is needed. Note that this step
2187  // may restructure the CFG.
2188  for (CallBase *Call : ToUpdate) {
2189  auto *II = dyn_cast<InvokeInst>(Call);
2190  if (!II)
2191  continue;
2192  normalizeForInvokeSafepoint(II->getNormalDest(), II->getParent(), DT);
2193  normalizeForInvokeSafepoint(II->getUnwindDest(), II->getParent(), DT);
2194  }
2195 
2196  // A list of dummy calls added to the IR to keep various values obviously
2197  // live in the IR. We'll remove all of these when done.
2199 
2200  // Insert a dummy call with all of the deopt operands we'll need for the
2201  // actual safepoint insertion as arguments. This ensures reference operands
2202  // in the deopt argument list are considered live through the safepoint (and
2203  // thus makes sure they get relocated.)
2204  for (CallBase *Call : ToUpdate) {
2205  SmallVector<Value *, 64> DeoptValues;
2206 
2207  for (Value *Arg : GetDeoptBundleOperands(Call)) {
2208  assert(!isUnhandledGCPointerType(Arg->getType()) &&
2209  "support for FCA unimplemented");
2210  if (isHandledGCPointerType(Arg->getType()))
2211  DeoptValues.push_back(Arg);
2212  }
2213 
2214  insertUseHolderAfter(Call, DeoptValues, Holders);
2215  }
2216 
2218 
2219  // A) Identify all gc pointers which are statically live at the given call
2220  // site.
2221  findLiveReferences(F, DT, ToUpdate, Records);
2222 
2223  // B) Find the base pointers for each live pointer
2224  /* scope for caching */ {
2225  // Cache the 'defining value' relation used in the computation and
2226  // insertion of base phis and selects. This ensures that we don't insert
2227  // large numbers of duplicate base_phis.
2228  DefiningValueMapTy DVCache;
2229 
2230  for (size_t i = 0; i < Records.size(); i++) {
2231  PartiallyConstructedSafepointRecord &info = Records[i];
2232  findBasePointers(DT, DVCache, ToUpdate[i], info);
2233  }
2234  } // end of cache scope
2235 
2236  // The base phi insertion logic (for any safepoint) may have inserted new
2237  // instructions which are now live at some safepoint. The simplest such
2238  // example is:
2239  // loop:
2240  // phi a <-- will be a new base_phi here
2241  // safepoint 1 <-- that needs to be live here
2242  // gep a + 1
2243  // safepoint 2
2244  // br loop
2245  // We insert some dummy calls after each safepoint to definitely hold live
2246  // the base pointers which were identified for that safepoint. We'll then
2247  // ask liveness for _every_ base inserted to see what is now live. Then we
2248  // remove the dummy calls.
2249  Holders.reserve(Holders.size() + Records.size());
2250  for (size_t i = 0; i < Records.size(); i++) {
2251  PartiallyConstructedSafepointRecord &Info = Records[i];
2252 
2254  for (auto Pair : Info.PointerToBase)
2255  Bases.push_back(Pair.second);
2256 
2257  insertUseHolderAfter(ToUpdate[i], Bases, Holders);
2258  }
2259 
2260  // By selecting base pointers, we've effectively inserted new uses. Thus, we
2261  // need to rerun liveness. We may *also* have inserted new defs, but that's
2262  // not the key issue.
2263  recomputeLiveInValues(F, DT, ToUpdate, Records);
2264 
2265  if (PrintBasePointers) {
2266  for (auto &Info : Records) {
2267  errs() << "Base Pairs: (w/Relocation)\n";
2268  for (auto Pair : Info.PointerToBase) {
2269  errs() << " derived ";
2270  Pair.first->printAsOperand(errs(), false);
2271  errs() << " base ";
2272  Pair.second->printAsOperand(errs(), false);
2273  errs() << "\n";
2274  }
2275  }
2276  }
2277 
2278  // It is possible that non-constant live variables have a constant base. For
2279  // example, a GEP with a variable offset from a global. In this case we can
2280  // remove it from the liveset. We already don't add constants to the liveset
2281  // because we assume they won't move at runtime and the GC doesn't need to be
2282  // informed about them. The same reasoning applies if the base is constant.
2283  // Note that the relocation placement code relies on this filtering for
2284  // correctness as it expects the base to be in the liveset, which isn't true
2285  // if the base is constant.
2286  for (auto &Info : Records)
2287  for (auto &BasePair : Info.PointerToBase)
2288  if (isa<Constant>(BasePair.second))
2289  Info.LiveSet.remove(BasePair.first);
2290 
2291  for (CallInst *CI : Holders)
2292  CI->eraseFromParent();
2293 
2294  Holders.clear();
2295 
2296  // In order to reduce live set of statepoint we might choose to rematerialize
2297  // some values instead of relocating them. This is purely an optimization and
2298  // does not influence correctness.
2299  for (size_t i = 0; i < Records.size(); i++)
2300  rematerializeLiveValues(ToUpdate[i], Records[i], TTI);
2301 
2302  // We need this to safely RAUW and delete call or invoke return values that
2303  // may themselves be live over a statepoint. For details, please see usage in
2304  // makeStatepointExplicitImpl.
2305  std::vector<DeferredReplacement> Replacements;
2306 
2307  // Now run through and replace the existing statepoints with new ones with
2308  // the live variables listed. We do not yet update uses of the values being
2309  // relocated. We have references to live variables that need to
2310  // survive to the last iteration of this loop. (By construction, the
2311  // previous statepoint can not be a live variable, thus we can and remove
2312  // the old statepoint calls as we go.)
2313  for (size_t i = 0; i < Records.size(); i++)
2314  makeStatepointExplicit(DT, ToUpdate[i], Records[i], Replacements);
2315 
2316  ToUpdate.clear(); // prevent accident use of invalid calls.
2317 
2318  for (auto &PR : Replacements)
2319  PR.doReplacement();
2320 
2321  Replacements.clear();
2322 
2323  for (auto &Info : Records) {
2324  // These live sets may contain state Value pointers, since we replaced calls
2325  // with operand bundles with calls wrapped in gc.statepoint, and some of
2326  // those calls may have been def'ing live gc pointers. Clear these out to
2327  // avoid accidentally using them.
2328  //
2329  // TODO: We should create a separate data structure that does not contain
2330  // these live sets, and migrate to using that data structure from this point
2331  // onward.
2332  Info.LiveSet.clear();
2333  Info.PointerToBase.clear();
2334  }
2335 
2336  // Do all the fixups of the original live variables to their relocated selves
2338  for (size_t i = 0; i < Records.size(); i++) {
2339  PartiallyConstructedSafepointRecord &Info = Records[i];
2340 
2341  // We can't simply save the live set from the original insertion. One of
2342  // the live values might be the result of a call which needs a safepoint.
2343  // That Value* no longer exists and we need to use the new gc_result.
2344  // Thankfully, the live set is embedded in the statepoint (and updated), so
2345  // we just grab that.
2346  Statepoint Statepoint(Info.StatepointToken);
2347  Live.insert(Live.end(), Statepoint.gc_args_begin(),
2348  Statepoint.gc_args_end());
2349 #ifndef NDEBUG
2350  // Do some basic sanity checks on our liveness results before performing
2351  // relocation. Relocation can and will turn mistakes in liveness results
2352  // into non-sensical code which is must harder to debug.
2353  // TODO: It would be nice to test consistency as well
2354  assert(DT.isReachableFromEntry(Info.StatepointToken->getParent()) &&
2355  "statepoint must be reachable or liveness is meaningless");
2356  for (Value *V : Statepoint.gc_args()) {
2357  if (!isa<Instruction>(V))
2358  // Non-instruction values trivial dominate all possible uses
2359  continue;
2360  auto *LiveInst = cast<Instruction>(V);
2361  assert(DT.isReachableFromEntry(LiveInst->getParent()) &&
2362  "unreachable values should never be live");
2363  assert(DT.dominates(LiveInst, Info.StatepointToken) &&
2364  "basic SSA liveness expectation violated by liveness analysis");
2365  }
2366 #endif
2367  }
2368  unique_unsorted(Live);
2369 
2370 #ifndef NDEBUG
2371  // sanity check
2372  for (auto *Ptr : Live)
2373  assert(isHandledGCPointerType(Ptr->getType()) &&
2374  "must be a gc pointer type");
2375 #endif
2376 
2377  relocationViaAlloca(F, DT, Live, Records);
2378  return !Records.empty();
2379 }
2380 
2381 // Handles both return values and arguments for Functions and calls.
2382 template <typename AttrHolder>
2383 static void RemoveNonValidAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH,
2384  unsigned Index) {
2385  AttrBuilder R;
2386  if (AH.getDereferenceableBytes(Index))
2387  R.addAttribute(Attribute::get(Ctx, Attribute::Dereferenceable,
2388  AH.getDereferenceableBytes(Index)));
2389  if (AH.getDereferenceableOrNullBytes(Index))
2390  R.addAttribute(Attribute::get(Ctx, Attribute::DereferenceableOrNull,
2391  AH.getDereferenceableOrNullBytes(Index)));
2392  if (AH.getAttributes().hasAttribute(Index, Attribute::NoAlias))
2394 
2395  if (!R.empty())
2396  AH.setAttributes(AH.getAttributes().removeAttributes(Ctx, Index, R));
2397 }
2398 
2400  LLVMContext &Ctx = F.getContext();
2401 
2402  for (Argument &A : F.args())
2403  if (isa<PointerType>(A.getType()))
2405  A.getArgNo() + AttributeList::FirstArgIndex);
2406 
2407  if (isa<PointerType>(F.getReturnType()))
2409 }
2410 
2411 /// Certain metadata on instructions are invalid after running RS4GC.
2412 /// Optimizations that run after RS4GC can incorrectly use this metadata to
2413 /// optimize functions. We drop such metadata on the instruction.
2415  if (!isa<LoadInst>(I) && !isa<StoreInst>(I))
2416  return;
2417  // These are the attributes that are still valid on loads and stores after
2418  // RS4GC.
2419  // The metadata implying dereferenceability and noalias are (conservatively)
2420  // dropped. This is because semantically, after RewriteStatepointsForGC runs,
2421  // all calls to gc.statepoint "free" the entire heap. Also, gc.statepoint can
2422  // touch the entire heap including noalias objects. Note: The reasoning is
2423  // same as stripping the dereferenceability and noalias attributes that are
2424  // analogous to the metadata counterparts.
2425  // We also drop the invariant.load metadata on the load because that metadata
2426  // implies the address operand to the load points to memory that is never
2427  // changed once it became dereferenceable. This is no longer true after RS4GC.
2428  // Similar reasoning applies to invariant.group metadata, which applies to
2429  // loads within a group.
2430  unsigned ValidMetadataAfterRS4GC[] = {LLVMContext::MD_tbaa,
2431  LLVMContext::MD_range,
2432  LLVMContext::MD_alias_scope,
2433  LLVMContext::MD_nontemporal,
2434  LLVMContext::MD_nonnull,
2435  LLVMContext::MD_align,
2436  LLVMContext::MD_type};
2437 
2438  // Drops all metadata on the instruction other than ValidMetadataAfterRS4GC.
2439  I.dropUnknownNonDebugMetadata(ValidMetadataAfterRS4GC);
2440 }
2441 
2443  if (F.empty())
2444  return;
2445 
2446  LLVMContext &Ctx = F.getContext();
2447  MDBuilder Builder(Ctx);
2448 
2449  // Set of invariantstart instructions that we need to remove.
2450  // Use this to avoid invalidating the instruction iterator.
2451  SmallVector<IntrinsicInst*, 12> InvariantStartInstructions;
2452 
2453  for (Instruction &I : instructions(F)) {
2454  // invariant.start on memory location implies that the referenced memory
2455  // location is constant and unchanging. This is no longer true after
2456  // RewriteStatepointsForGC runs because there can be calls to gc.statepoint
2457  // which frees the entire heap and the presence of invariant.start allows
2458  // the optimizer to sink the load of a memory location past a statepoint,
2459  // which is incorrect.
2460  if (auto *II = dyn_cast<IntrinsicInst>(&I))
2461  if (II->getIntrinsicID() == Intrinsic::invariant_start) {
2462  InvariantStartInstructions.push_back(II);
2463  continue;
2464  }
2465 
2466  if (MDNode *Tag = I.getMetadata(LLVMContext::MD_tbaa)) {
2467  MDNode *MutableTBAA = Builder.createMutableTBAAAccessTag(Tag);
2468  I.setMetadata(LLVMContext::MD_tbaa, MutableTBAA);
2469  }
2470 
2472 
2473  if (auto *Call = dyn_cast<CallBase>(&I)) {
2474  for (int i = 0, e = Call->arg_size(); i != e; i++)
2475  if (isa<PointerType>(Call->getArgOperand(i)->getType()))
2476  RemoveNonValidAttrAtIndex(Ctx, *Call,
2478  if (isa<PointerType>(Call->getType()))
2480  }
2481  }
2482 
2483  // Delete the invariant.start instructions and RAUW undef.
2484  for (auto *II : InvariantStartInstructions) {
2485  II->replaceAllUsesWith(UndefValue::get(II->getType()));
2486  II->eraseFromParent();
2487  }
2488 }
2489 
2490 /// Returns true if this function should be rewritten by this pass. The main
2491 /// point of this function is as an extension point for custom logic.
2493  // TODO: This should check the GCStrategy
2494  if (F.hasGC()) {
2495  const auto &FunctionGCName = F.getGC();
2496  const StringRef StatepointExampleName("statepoint-example");
2497  const StringRef CoreCLRName("coreclr");
2498  return (StatepointExampleName == FunctionGCName) ||
2499  (CoreCLRName == FunctionGCName);
2500  } else
2501  return false;
2502 }
2503 
2504 static void stripNonValidData(Module &M) {
2505 #ifndef NDEBUG
2506  assert(llvm::any_of(M, shouldRewriteStatepointsIn) && "precondition!");
2507 #endif
2508 
2509  for (Function &F : M)
2511 
2512  for (Function &F : M)
2514 }
2515 
2517  TargetTransformInfo &TTI,
2518  const TargetLibraryInfo &TLI) {
2519  assert(!F.isDeclaration() && !F.empty() &&
2520  "need function body to rewrite statepoints in");
2521  assert(shouldRewriteStatepointsIn(F) && "mismatch in rewrite decision");
2522 
2523  auto NeedsRewrite = [&TLI](Instruction &I) {
2524  if (const auto *Call = dyn_cast<CallBase>(&I))
2525  return !callsGCLeafFunction(Call, TLI) && !isStatepoint(Call);
2526  return false;
2527  };
2528 
2529  // Delete any unreachable statepoints so that we don't have unrewritten
2530  // statepoints surviving this pass. This makes testing easier and the
2531  // resulting IR less confusing to human readers.
2533  bool MadeChange = removeUnreachableBlocks(F, &DTU);
2534  // Flush the Dominator Tree.
2535  DTU.getDomTree();
2536 
2537  // Gather all the statepoints which need rewritten. Be careful to only
2538  // consider those in reachable code since we need to ask dominance queries
2539  // when rewriting. We'll delete the unreachable ones in a moment.
2540  SmallVector<CallBase *, 64> ParsePointNeeded;
2541  for (Instruction &I : instructions(F)) {
2542  // TODO: only the ones with the flag set!
2543  if (NeedsRewrite(I)) {
2544  // NOTE removeUnreachableBlocks() is stronger than
2545  // DominatorTree::isReachableFromEntry(). In other words
2546  // removeUnreachableBlocks can remove some blocks for which
2547  // isReachableFromEntry() returns true.
2548  assert(DT.isReachableFromEntry(I.getParent()) &&
2549  "no unreachable blocks expected");
2550  ParsePointNeeded.push_back(cast<CallBase>(&I));
2551  }
2552  }
2553 
2554  // Return early if no work to do.
2555  if (ParsePointNeeded.empty())
2556  return MadeChange;
2557 
2558  // As a prepass, go ahead and aggressively destroy single entry phi nodes.
2559  // These are created by LCSSA. They have the effect of increasing the size
2560  // of liveness sets for no good reason. It may be harder to do this post
2561  // insertion since relocations and base phis can confuse things.
2562  for (BasicBlock &BB : F)
2563  if (BB.getUniquePredecessor()) {
2564  MadeChange = true;
2566  }
2567 
2568  // Before we start introducing relocations, we want to tweak the IR a bit to
2569  // avoid unfortunate code generation effects. The main example is that we
2570  // want to try to make sure the comparison feeding a branch is after any
2571  // safepoints. Otherwise, we end up with a comparison of pre-relocation
2572  // values feeding a branch after relocation. This is semantically correct,
2573  // but results in extra register pressure since both the pre-relocation and
2574  // post-relocation copies must be available in registers. For code without
2575  // relocations this is handled elsewhere, but teaching the scheduler to
2576  // reverse the transform we're about to do would be slightly complex.
2577  // Note: This may extend the live range of the inputs to the icmp and thus
2578  // increase the liveset of any statepoint we move over. This is profitable
2579  // as long as all statepoints are in rare blocks. If we had in-register
2580  // lowering for live values this would be a much safer transform.
2581  auto getConditionInst = [](Instruction *TI) -> Instruction * {
2582  if (auto *BI = dyn_cast<BranchInst>(TI))
2583  if (BI->isConditional())
2584  return dyn_cast<Instruction>(BI->getCondition());
2585  // TODO: Extend this to handle switches
2586  return nullptr;
2587  };
2588  for (BasicBlock &BB : F) {
2589  Instruction *TI = BB.getTerminator();
2590  if (auto *Cond = getConditionInst(TI))
2591  // TODO: Handle more than just ICmps here. We should be able to move
2592  // most instructions without side effects or memory access.
2593  if (isa<ICmpInst>(Cond) && Cond->hasOneUse()) {
2594  MadeChange = true;
2595  Cond->moveBefore(TI);
2596  }
2597  }
2598 
2599  // Nasty workaround - The base computation code in the main algorithm doesn't
2600  // consider the fact that a GEP can be used to convert a scalar to a vector.
2601  // The right fix for this is to integrate GEPs into the base rewriting
2602  // algorithm properly, this is just a short term workaround to prevent
2603  // crashes by canonicalizing such GEPs into fully vector GEPs.
2604  for (Instruction &I : instructions(F)) {
2605  if (!isa<GetElementPtrInst>(I))
2606  continue;
2607 
2608  unsigned VF = 0;
2609  for (unsigned i = 0; i < I.getNumOperands(); i++)
2610  if (I.getOperand(i)->getType()->isVectorTy()) {
2611  assert(VF == 0 ||
2612  VF == I.getOperand(i)->getType()->getVectorNumElements());
2613  VF = I.getOperand(i)->getType()->getVectorNumElements();
2614  }
2615 
2616  // It's the vector to scalar traversal through the pointer operand which
2617  // confuses base pointer rewriting, so limit ourselves to that case.
2618  if (!I.getOperand(0)->getType()->isVectorTy() && VF != 0) {
2619  IRBuilder<> B(&I);
2620  auto *Splat = B.CreateVectorSplat(VF, I.getOperand(0));
2621  I.setOperand(0, Splat);
2622  MadeChange = true;
2623  }
2624  }
2625 
2626  MadeChange |= insertParsePoints(F, DT, TTI, ParsePointNeeded);
2627  return MadeChange;
2628 }
2629 
2630 // liveness computation via standard dataflow
2631 // -------------------------------------------------------------------
2632 
2633 // TODO: Consider using bitvectors for liveness, the set of potentially
2634 // interesting values should be small and easy to pre-compute.
2635 
2636 /// Compute the live-in set for the location rbegin starting from
2637 /// the live-out set of the basic block
2640  SetVector<Value *> &LiveTmp) {
2641  for (auto &I : make_range(Begin, End)) {
2642  // KILL/Def - Remove this definition from LiveIn
2643  LiveTmp.remove(&I);
2644 
2645  // Don't consider *uses* in PHI nodes, we handle their contribution to
2646  // predecessor blocks when we seed the LiveOut sets
2647  if (isa<PHINode>(I))
2648  continue;
2649 
2650  // USE - Add to the LiveIn set for this instruction
2651  for (Value *V : I.operands()) {
2653  "support for FCA unimplemented");
2654  if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V)) {
2655  // The choice to exclude all things constant here is slightly subtle.
2656  // There are two independent reasons:
2657  // - We assume that things which are constant (from LLVM's definition)
2658  // do not move at runtime. For example, the address of a global
2659  // variable is fixed, even though it's contents may not be.
2660  // - Second, we can't disallow arbitrary inttoptr constants even
2661  // if the language frontend does. Optimization passes are free to
2662  // locally exploit facts without respect to global reachability. This
2663  // can create sections of code which are dynamically unreachable and
2664  // contain just about anything. (see constants.ll in tests)
2665  LiveTmp.insert(V);
2666  }
2667  }
2668  }
2669 }
2670 
2672  for (BasicBlock *Succ : successors(BB)) {
2673  for (auto &I : *Succ) {
2674  PHINode *PN = dyn_cast<PHINode>(&I);
2675  if (!PN)
2676  break;
2677 
2678  Value *V = PN->getIncomingValueForBlock(BB);
2680  "support for FCA unimplemented");
2681  if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V))
2682  LiveTmp.insert(V);
2683  }
2684  }
2685 }
2686 
2688  SetVector<Value *> KillSet;
2689  for (Instruction &I : *BB)
2691  KillSet.insert(&I);
2692  return KillSet;
2693 }
2694 
2695 #ifndef NDEBUG
2696 /// Check that the items in 'Live' dominate 'TI'. This is used as a basic
2697 /// sanity check for the liveness computation.
2699  Instruction *TI, bool TermOkay = false) {
2700  for (Value *V : Live) {
2701  if (auto *I = dyn_cast<Instruction>(V)) {
2702  // The terminator can be a member of the LiveOut set. LLVM's definition
2703  // of instruction dominance states that V does not dominate itself. As
2704  // such, we need to special case this to allow it.
2705  if (TermOkay && TI == I)
2706  continue;
2707  assert(DT.dominates(I, TI) &&
2708  "basic SSA liveness expectation violated by liveness analysis");
2709  }
2710  }
2711 }
2712 
2713 /// Check that all the liveness sets used during the computation of liveness
2714 /// obey basic SSA properties. This is useful for finding cases where we miss
2715 /// a def.
2716 static void checkBasicSSA(DominatorTree &DT, GCPtrLivenessData &Data,
2717  BasicBlock &BB) {
2718  checkBasicSSA(DT, Data.LiveSet[&BB], BB.getTerminator());
2719  checkBasicSSA(DT, Data.LiveOut[&BB], BB.getTerminator(), true);
2720  checkBasicSSA(DT, Data.LiveIn[&BB], BB.getTerminator());
2721 }
2722 #endif
2723 
2725  GCPtrLivenessData &Data) {
2727 
2728  // Seed the liveness for each individual block
2729  for (BasicBlock &BB : F) {
2730  Data.KillSet[&BB] = computeKillSet(&BB);
2731  Data.LiveSet[&BB].clear();
2732  computeLiveInValues(BB.rbegin(), BB.rend(), Data.LiveSet[&BB]);
2733 
2734 #ifndef NDEBUG
2735  for (Value *Kill : Data.KillSet[&BB])
2736  assert(!Data.LiveSet[&BB].count(Kill) && "live set contains kill");
2737 #endif
2738 
2739  Data.LiveOut[&BB] = SetVector<Value *>();
2740  computeLiveOutSeed(&BB, Data.LiveOut[&BB]);
2741  Data.LiveIn[&BB] = Data.LiveSet[&BB];
2742  Data.LiveIn[&BB].set_union(Data.LiveOut[&BB]);
2743  Data.LiveIn[&BB].set_subtract(Data.KillSet[&BB]);
2744  if (!Data.LiveIn[&BB].empty())
2745  Worklist.insert(pred_begin(&BB), pred_end(&BB));
2746  }
2747 
2748  // Propagate that liveness until stable
2749  while (!Worklist.empty()) {
2750  BasicBlock *BB = Worklist.pop_back_val();
2751 
2752  // Compute our new liveout set, then exit early if it hasn't changed despite
2753  // the contribution of our successor.
2754  SetVector<Value *> LiveOut = Data.LiveOut[BB];
2755  const auto OldLiveOutSize = LiveOut.size();
2756  for (BasicBlock *Succ : successors(BB)) {
2757  assert(Data.LiveIn.count(Succ));
2758  LiveOut.set_union(Data.LiveIn[Succ]);
2759  }
2760  // assert OutLiveOut is a subset of LiveOut
2761  if (OldLiveOutSize == LiveOut.size()) {
2762  // If the sets are the same size, then we didn't actually add anything
2763  // when unioning our successors LiveIn. Thus, the LiveIn of this block
2764  // hasn't changed.
2765  continue;
2766  }
2767  Data.LiveOut[BB] = LiveOut;
2768 
2769  // Apply the effects of this basic block
2770  SetVector<Value *> LiveTmp = LiveOut;
2771  LiveTmp.set_union(Data.LiveSet[BB]);
2772  LiveTmp.set_subtract(Data.KillSet[BB]);
2773 
2774  assert(Data.LiveIn.count(BB));
2775  const SetVector<Value *> &OldLiveIn = Data.LiveIn[BB];
2776  // assert: OldLiveIn is a subset of LiveTmp
2777  if (OldLiveIn.size() != LiveTmp.size()) {
2778  Data.LiveIn[BB] = LiveTmp;
2779  Worklist.insert(pred_begin(BB), pred_end(BB));
2780  }
2781  } // while (!Worklist.empty())
2782 
2783 #ifndef NDEBUG
2784  // Sanity check our output against SSA properties. This helps catch any
2785  // missing kills during the above iteration.
2786  for (BasicBlock &BB : F)
2787  checkBasicSSA(DT, Data, BB);
2788 #endif
2789 }
2790 
2791 static void findLiveSetAtInst(Instruction *Inst, GCPtrLivenessData &Data,
2792  StatepointLiveSetTy &Out) {
2793  BasicBlock *BB = Inst->getParent();
2794 
2795  // Note: The copy is intentional and required
2796  assert(Data.LiveOut.count(BB));
2797  SetVector<Value *> LiveOut = Data.LiveOut[BB];
2798 
2799  // We want to handle the statepoint itself oddly. It's
2800  // call result is not live (normal), nor are it's arguments
2801  // (unless they're used again later). This adjustment is
2802  // specifically what we need to relocate
2803  computeLiveInValues(BB->rbegin(), ++Inst->getIterator().getReverse(),
2804  LiveOut);
2805  LiveOut.remove(Inst);
2806  Out.insert(LiveOut.begin(), LiveOut.end());
2807 }
2808 
2809 static void recomputeLiveInValues(GCPtrLivenessData &RevisedLivenessData,
2810  CallBase *Call,
2811  PartiallyConstructedSafepointRecord &Info) {
2812  StatepointLiveSetTy Updated;
2813  findLiveSetAtInst(Call, RevisedLivenessData, Updated);
2814 
2815  // We may have base pointers which are now live that weren't before. We need
2816  // to update the PointerToBase structure to reflect this.
2817  for (auto V : Updated)
2818  if (Info.PointerToBase.insert({V, V}).second) {
2820  "Can't find base for unexpected live value!");
2821  continue;
2822  }
2823 
2824 #ifndef NDEBUG
2825  for (auto V : Updated)
2826  assert(Info.PointerToBase.count(V) &&
2827  "Must be able to find base for live value!");
2828 #endif
2829 
2830  // Remove any stale base mappings - this can happen since our liveness is
2831  // more precise then the one inherent in the base pointer analysis.
2832  DenseSet<Value *> ToErase;
2833  for (auto KVPair : Info.PointerToBase)
2834  if (!Updated.count(KVPair.first))
2835  ToErase.insert(KVPair.first);
2836 
2837  for (auto *V : ToErase)
2838  Info.PointerToBase.erase(V);
2839 
2840 #ifndef NDEBUG
2841  for (auto KVPair : Info.PointerToBase)
2842  assert(Updated.count(KVPair.first) && "record for non-live value");
2843 #endif
2844 
2845  Info.LiveSet = Updated;
2846 }
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:67
static void rematerializeLiveValues(CallBase *Call, PartiallyConstructedSafepointRecord &Info, TargetTransformInfo &TTI)
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:112
static void unique_unsorted(SmallVectorImpl< T > &Vec)
Implement a unique function which doesn&#39;t require we sort the input vector.
static void computeLiveOutSeed(BasicBlock *BB, SetVector< Value *> &LiveTmp)
static bool isHandledGCPointerType(Type *T)
bool empty() const
Definition: Function.h:686
static cl::opt< bool, true > ClobberNonLiveOverride("rs4gc-clobber-non-live", cl::location(ClobberNonLive), cl::Hidden)
raw_ostream & errs()
This returns a reference to a raw_ostream for standard error.
MapVector< Value *, Value * > DefiningValueMapTy
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
static void insertRelocationStores(iterator_range< Value::user_iterator > GCRelocs, DenseMap< Value *, AllocaInst *> &AllocaMap, DenseSet< Value *> &VisitedLiveValues)
This class represents an incoming formal argument to a Function.
Definition: Argument.h:29
LLVM_NODISCARD std::string str() const
str - Get the contents as an std::string.
Definition: StringRef.h:232
static Value * findBaseDefiningValueCached(Value *I, DefiningValueMapTy &Cache)
Returns the base defining value for this value.
static bool AreEquivalentPhiNodes(PHINode &OrigRootPhi, PHINode &AlternateRootPhi)
static BDVState meetBDVStateImpl(const BDVState &LHS, const BDVState &RHS)
NodeTy * getNextNode()
Get the next node, or nullptr for the list tail.
Definition: ilist_node.h:288
PassT::Result & getResult(IRUnitT &IR, ExtraArgTs... ExtraArgs)
Get the result of an analysis pass for a given IR unit.
Definition: PassManager.h:776
This class represents lattice values for constants.
Definition: AllocatorList.h:23
#define LLVM_DUMP_METHOD
Mark debug helper function definitions like dump() that should not be stripped from debug builds...
Definition: Compiler.h:484
Instruction * StatepointToken
The new gc.statepoint instruction itself.
size_type size() const
Determine the number of elements in the SetVector.
Definition: SetVector.h:77
static void stripInvalidMetadataFromInstruction(Instruction &I)
Certain metadata on instructions are invalid after running RS4GC.
Instruction * UnwindToken
Instruction to which exceptional gc relocates are attached Makes it easier to iterate through them du...
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:65
void dropUnknownNonDebugMetadata(ArrayRef< unsigned > KnownIDs)
Drop all unknown metadata except for debug locations.
Definition: Metadata.cpp:1195
iterator begin() const
Definition: ArrayRef.h:136
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
StatepointDirectives parseStatepointDirectivesFromAttrs(AttributeList AS)
Parse out statepoint directives from the function attributes present in AS.
Definition: Statepoint.cpp:60
static CallInst * Create(FunctionType *Ty, Value *F, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
A handy container for a FunctionType+Callee-pointer pair, which can be passed around as a single enti...
Definition: DerivedTypes.h:170
static void checkBasicSSA(DominatorTree &DT, SetVector< Value *> &Live, Instruction *TI, bool TermOkay=false)
Check that the items in &#39;Live&#39; dominate &#39;TI&#39;.
static ConstantAggregateZero * get(Type *Ty)
Definition: Constants.cpp:1363
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
This class represents a function call, abstracting a target machine&#39;s calling convention.
INITIALIZE_PASS_BEGIN(RewriteStatepointsForGCLegacyPass, "rewrite-statepoints-for-gc", "Make relocations explicit at statepoints", false, false) INITIALIZE_PASS_END(RewriteStatepointsForGCLegacyPass
This file contains the declarations for metadata subclasses.
DominatorTree & getDomTree()
Flush DomTree updates and return DomTree.
Optional< std::vector< StOtherPiece > > Other
Definition: ELFYAML.cpp:953
static void insertUseHolderAfter(CallBase *Call, const ArrayRef< Value *> Values, SmallVectorImpl< CallInst *> &Holders)
Insert holders so that each Value is obviously live through the entire lifetime of the call...
MapVector< BasicBlock *, SetVector< Value * > > KillSet
Values defined in this block.
const Value * getTrueValue() const
The two locations do not alias at all.
Definition: AliasAnalysis.h:84
Analysis pass providing the TargetTransformInfo.
This instruction constructs a fixed permutation of two input vectors.
static SelectInst * Create(Value *C, Value *S1, Value *S2, const Twine &NameStr="", Instruction *InsertBefore=nullptr, Instruction *MDFrom=nullptr)
MapVector< BasicBlock *, SetVector< Value * > > LiveSet
Values used in this block (and thus live); does not included values killed within this block...
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:743
static void stripNonValidAttributesFromPrototype(Function &F)
MapVector< BasicBlock *, SetVector< Value * > > LiveIn
Values live into this basic block (i.e.
bool hasFnAttribute(Attribute::AttrKind Kind) const
Return true if the function has the attribute.
Definition: Function.h:323
This class implements a map that also provides access to all stored values in a deterministic order...
Definition: MapVector.h:37
Metadata node.
Definition: Metadata.h:863
Base class for all callable instructions (InvokeInst and CallInst) Holds everything related to callin...
Definition: InstrTypes.h:1100
Analysis pass which computes a DominatorTree.
Definition: Dominators.h:230
F(f)
User::op_iterator arg_end()
Return the iterator pointing to the end of the argument list.
Definition: InstrTypes.h:1212
An instruction for reading from memory.
Definition: Instructions.h:169
reverse_iterator rbegin()
Definition: BasicBlock.h:278
AttrBuilder & addAttribute(Attribute::AttrKind Val)
Add an attribute to the builder.
Hexagon Common GEP
const Instruction * getTerminator() const LLVM_READONLY
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.cpp:144
bool isVectorTy() const
True if this is an instance of VectorType.
Definition: Type.h:230
static void stripNonValidDataFromBody(Function &F)
static BaseDefiningValueResult findBaseDefiningValueOfVector(Value *I)
Return a base defining value for the &#39;Index&#39; element of the given vector instruction &#39;I&#39;...
void reserve(size_type N)
Definition: SmallVector.h:369
static void makeStatepointExplicit(DominatorTree &DT, CallBase *Call, PartiallyConstructedSafepointRecord &Result, std::vector< DeferredReplacement > &Replacements)
bool isReachableFromEntry(const Use &U) const
Provide an overload for a Use.
Definition: Dominators.cpp:299
bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const
Return true if the attribute exists at the given index.
static void computeLiveInValues(DominatorTree &DT, Function &F, GCPtrLivenessData &Data)
Compute the live-in set for every basic block in the function.
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:273
Value * getArgOperand(unsigned i) const
Definition: InstrTypes.h:1241
unsigned getAllocaAddrSpace() const
Definition: DataLayout.h:274
AnalysisUsage & addRequired()
static InsertElementInst * Create(Value *Vec, Value *NewElt, Value *Idx, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
#define INITIALIZE_PASS_DEPENDENCY(depName)
Definition: PassSupport.h:50
static void makeStatepointExplicitImpl(CallBase *Call, const SmallVectorImpl< Value *> &BasePtrs, const SmallVectorImpl< Value *> &LiveVariables, PartiallyConstructedSafepointRecord &Result, std::vector< DeferredReplacement > &Replacements)
static void relocationViaAlloca(Function &F, DominatorTree &DT, ArrayRef< Value *> Live, ArrayRef< PartiallyConstructedSafepointRecord > Records)
Do all the relocation update via allocas and mem2reg.
This class represents the LLVM &#39;select&#39; instruction.
const DataLayout & getDataLayout() const
Get the data layout for the module&#39;s target platform.
Definition: Module.cpp:369
This is the base class for all instructions that perform data casts.
Definition: InstrTypes.h:439
&#39;undef&#39; values are things that do not have specified contents.
Definition: Constants.h:1285
int getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src, const Instruction *I=nullptr) const
static bool isKnownBaseResult(Value *V)
Given the result of a call to findBaseDefiningValue, or findBaseOrBDV, is it known to be a base point...
Class to represent struct types.
Definition: DerivedTypes.h:238
LLVMContext & getContext() const
Get the global data context.
Definition: Module.h:244
static Value * findBasePointer(Value *I, DefiningValueMapTy &Cache)
For a given value or instruction, figure out what base ptr its derived from.
A Use represents the edge between a Value definition and its users.
Definition: Use.h:55
Value * getDerivedPtr() const
Definition: Statepoint.h:387
static Value * findRematerializableChainToBasePointer(SmallVectorImpl< Instruction *> &ChainToBase, Value *CurrentValue)
static bool isGCPointerType(Type *T)
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:779
This file contains the simple types necessary to represent the attributes associated with functions a...
AttributeSet getRetAttributes() const
The attributes for the ret value are returned.
static ArrayRef< Use > GetDeoptBundleOperands(const CallBase *Call)
void setName(const Twine &Name)
Change the name of the value.
Definition: Value.cpp:285
arg_iterator gc_args_begin() const
Definition: Statepoint.h:241
bool remove(const value_type &X)
Remove an item from the set vector.
Definition: SetVector.h:157
void initializeRewriteStatepointsForGCLegacyPassPass(PassRegistry &)
LLVMContext & getContext() const
Retrieve the LLVM context.
auto reverse(ContainerTy &&C, typename std::enable_if< has_rbegin< ContainerTy >::value >::type *=nullptr) -> decltype(make_range(C.rbegin(), C.rend()))
Definition: STLExtras.h:261
static cl::opt< bool > PrintLiveSet("spp-print-liveset", cl::Hidden, cl::init(false))
Instruction * clone() const
Create a copy of &#39;this&#39; instruction that is identical in all ways except the following: ...
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:245
bool insert(const value_type &X)
Insert a new element into the SetVector.
Definition: SetVector.h:141
bool isStatepoint(const CallBase *Call)
Definition: Statepoint.cpp:20
const T & getValue() const LLVM_LVALUE_FUNCTION
Definition: Optional.h:255
const BasicBlock * getUniquePredecessor() const
Return the predecessor of this block if it has a unique predecessor block.
Definition: BasicBlock.cpp:253
Class to represent array types.
Definition: DerivedTypes.h:408
iterator_range< arg_iterator > gc_args() const
range adapter for gc arguments
Definition: Statepoint.h:249
This class represents a no-op cast from one type to another.
Value * CreateVectorSplat(unsigned NumElts, Value *V, const Twine &Name="")
Return a vector value that contains.
Definition: IRBuilder.h:2465
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:32
AttrBuilder & remove(const AttrBuilder &B)
Remove the attributes from the builder.
const std::string & getGC() const
Definition: Function.cpp:478
An instruction for storing to memory.
Definition: Instructions.h:325
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:429
ModulePass * createRewriteStatepointsForGCLegacyPass()
StatepointLiveSetTy LiveSet
The set of values known to be live across this safepoint.
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:144
int getAddressComputationCost(Type *Ty, ScalarEvolution *SE=nullptr, const SCEV *Ptr=nullptr) const
Function * getDeclaration(Module *M, ID id, ArrayRef< Type *> Tys=None)
Create or insert an LLVM Function declaration for an intrinsic, and return it.
Definition: Function.cpp:1093
PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM)
Analysis containing CSE Info
Definition: CSEInfo.cpp:20
Optional< OperandBundleUse > getOperandBundle(StringRef Name) const
Return an operand bundle by name, if present.
Definition: InstrTypes.h:1808
static unsigned chainToBasePointerCost(SmallVectorImpl< Instruction *> &Chain, TargetTransformInfo &TTI)
SetVector< Value * > StatepointLiveSetTy
void replaceUsesOfWith(Value *From, Value *To)
Replace uses of one Value with another.
Definition: User.cpp:20
static SetVector< Value * > computeKillSet(BasicBlock *BB)
bool isVoidTy() const
Return true if this is &#39;void&#39;.
Definition: Type.h:141
const BasicBlock & getEntryBlock() const
Definition: Function.h:664
an instruction for type-safe pointer arithmetic to access elements of arrays and structs ...
Definition: Instructions.h:883
static MDTuple * get(LLVMContext &Context, ArrayRef< Metadata *> MDs)
Definition: Metadata.h:1165
BasicBlock * SplitBlockPredecessors(BasicBlock *BB, ArrayRef< BasicBlock *> Preds, const char *Suffix, DominatorTree *DT=nullptr, LoopInfo *LI=nullptr, MemorySSAUpdater *MSSAU=nullptr, bool PreserveLCSSA=false)
This method introduces at least one new basic block into the function and moves some of the predecess...
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:432
Type * getReturnType() const
Returns the type of the ret val.
Definition: Function.h:168
static void recomputeLiveInValues(GCPtrLivenessData &RevisedLivenessData, CallBase *Call, PartiallyConstructedSafepointRecord &result)
Given an updated version of the dataflow liveness results, update the liveset and base pointer maps f...
static void RemoveNonValidAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH, unsigned Index)
const Instruction * getFirstNonPHI() const
Returns a pointer to the first instruction in this block that is not a PHINode instruction.
Definition: BasicBlock.cpp:196
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
void dump(const SparseBitVector< ElementSize > &LHS, raw_ostream &out)
Wrapper pass for TargetTransformInfo.
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:153
static AttributeSet get(LLVMContext &C, const AttrBuilder &B)
Definition: Attributes.cpp:592
const_iterator getFirstInsertionPt() const
Returns an iterator to the first instruction in this block that is suitable for inserting a non-PHI i...
Definition: BasicBlock.cpp:223
static ConstantPointerNull * get(PointerType *T)
Static factory methods - Return objects of the specified value.
Definition: Constants.cpp:1432
MutableArrayRef - Represent a mutable reference to an array (0 or more elements consecutively in memo...
Definition: ArrayRef.h:290
unsigned arg_size() const
Definition: InstrTypes.h:1229
void insertBefore(Instruction *InsertPos)
Insert an unlinked instruction into a basic block immediately before the specified instruction...
Definition: Instruction.cpp:73
Value * getCalledValue() const
Definition: InstrTypes.h:1280
bool hasName() const
Definition: Value.h:251
LLVM Basic Block Representation.
Definition: BasicBlock.h:57
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:64
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:148
This function has undefined behavior.
This is an important base class in LLVM.
Definition: Constant.h:41
bool set_union(const STy &S)
Compute This := This u S, return whether &#39;This&#39; changed.
Definition: SetVector.h:245
ArrayRef< Use > Inputs
Definition: InstrTypes.h:1001
static cl::opt< unsigned > RematerializationThreshold("spp-rematerialization-threshold", cl::Hidden, cl::init(6))
Value * getIncomingValueForBlock(const BasicBlock *BB) const
SmallSet - This maintains a set of unique values, optimizing for the case when the set is small (less...
Definition: SmallSet.h:134
This file contains the declarations for the subclasses of Constant, which represent the different fla...
static AttributeList legalizeCallAttributes(AttributeList AL)
std::pair< iterator, bool > insert(const ValueT &V)
Definition: DenseSet.h:187
Interval::pred_iterator pred_begin(Interval *I)
pred_begin/pred_end - define methods so that Intervals may be used just like BasicBlocks can with the...
Definition: Interval.h:112
bool runOnFunction(Function &F, DominatorTree &, TargetTransformInfo &, const TargetLibraryInfo &)
Optional< uint32_t > NumPatchBytes
Definition: Statepoint.h:438
Represent the analysis usage information of a pass.
static Type * getVoidTy(LLVMContext &C)
Definition: Type.cpp:165
bool any_of(R &&range, UnaryPredicate P)
Provide wrappers to std::any_of which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1172
RematerializedValueMapTy RematerializedValues
Record live values we are rematerialized instead of relocating.
constexpr double e
Definition: MathExtras.h:57
void setCallingConv(CallingConv::ID CC)
Definition: InstrTypes.h:1348
amdgpu Simplify well known AMD library false FunctionCallee Value * Arg
static FunctionType * get(Type *Result, ArrayRef< Type *> Params, bool isVarArg)
This static method is the primary way of constructing a FunctionType.
Definition: Type.cpp:301
A specialization of it&#39;s base class for read-write access to a gc.statepoint.
Definition: Statepoint.h:305
Interval::pred_iterator pred_end(Interval *I)
Definition: Interval.h:115
static void print(raw_ostream &Out, object::Archive::Kind Kind, T Val)
self_iterator getIterator()
Definition: ilist_node.h:81
std::pair< NoneType, bool > insert(const T &V)
insert - Insert an element into the set if it isn&#39;t already there.
Definition: SmallSet.h:180
static void stripNonValidData(Module &M)
The IR fed into RewriteStatepointsForGC may have had attributes and metadata implying dereferenceabil...
void setTailCallKind(TailCallKind TCK)
const Function * getFunction() const
Return the function this instruction belongs to.
Definition: Instruction.cpp:59
lazy value info
static bool containsGCPtrType(Type *Ty)
Returns true if this type contains a gc pointer whether we know how to handle that type or not...
auto remove_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range))
Provide wrappers to std::remove_if which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1205
LLVMContext & getContext() const
getContext - Return a reference to the LLVMContext associated with this function. ...
Definition: Function.cpp:205
static StringRef getDeoptLowering(CallBase *Call)
static UndefValue * get(Type *T)
Static factory methods - Return an &#39;undef&#39; object of the specified type.
Definition: Constants.cpp:1446
const Value * stripPointerCasts() const
Strip off pointer casts, all-zero GEPs and address space casts.
Definition: Value.cpp:529
iterator erase(const_iterator CI)
Definition: SmallVector.h:434
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
Definition: PassManager.h:159
Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const
Return the attribute object that exists at the given index.
static void findLiveSetAtInst(Instruction *inst, GCPtrLivenessData &Data, StatepointLiveSetTy &out)
Given results from the dataflow liveness computation, find the set of live Values at a particular ins...
size_t size() const
Definition: SmallVector.h:52
Value * getIncomingValue(unsigned i) const
Return incoming value number x.
bool hasFnAttr(Attribute::AttrKind Kind) const
Determine whether this call has the given attribute.
Definition: InstrTypes.h:1373
auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range))
Provide wrappers to std::find which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1186
static PointerType * getInt8PtrTy(LLVMContext &C, unsigned AS=0)
Definition: Type.cpp:224
static Value * findBaseOrBDV(Value *I, DefiningValueMapTy &Cache)
Return a base pointer for this value if known.
INITIALIZE_PASS_END(RegBankSelect, DEBUG_TYPE, "Assign register bank of generic virtual registers", false, false) RegBankSelect
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
void setMetadata(unsigned KindID, MDNode *Node)
Set the metadata of the specified kind to the specified node.
Definition: Metadata.cpp:1222
Type * getAllocatedType() const
Return the type that is being allocated by the instruction.
Definition: Instructions.h:105
static bool shouldRewriteStatepointsIn(Function &F)
Returns true if this function should be rewritten by this pass.
void sort(IteratorTy Start, IteratorTy End)
Definition: STLExtras.h:1095
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
bool isPtrOrPtrVectorTy() const
Return true if this is a pointer type or a vector of pointer types.
Definition: Type.h:227
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: MapVector.h:117
static cl::opt< bool > PrintBasePointers("spp-print-base-pointers", cl::Hidden, cl::init(false))
static cl::opt< bool > AllowStatepointWithNoDeoptInfo("rs4gc-allow-statepoint-with-no-deopt-info", cl::Hidden, cl::init(true))
A SetVector that performs no allocations if smaller than a certain size.
Definition: SetVector.h:297
This pass provides access to the codegen interfaces that are needed for IR-level transformations.
arg_iterator gc_args_end() const
Definition: Statepoint.h:242
AttrBuilder & removeAttribute(Attribute::AttrKind Val)
Remove an attribute from the builder.
bool callsGCLeafFunction(const CallBase *Call, const TargetLibraryInfo &TLI)
Return true if this call calls a gc leaf function.
Definition: Local.cpp:2515
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:837
static BDVState meetBDVState(const BDVState &LHS, const BDVState &RHS)
bool dominates(const Instruction *Def, const Use &U) const
Return true if Def dominates a use in User.
Definition: Dominators.cpp:248
Module.h This file contains the declarations for the Module class.
Provides information about what library functions are available for the current target.
iterator end() const
Definition: ArrayRef.h:137
Indicates that this statepoint is a transition from GC-aware code to code that is not GC-aware...
LLVM_NODISCARD T pop_back_val()
Definition: SmallVector.h:374
ConstantInt * getInt32(uint32_t C)
Get a constant 32-bit value.
Definition: IRBuilder.h:343
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
static BasicBlock * normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent, DominatorTree &DT)
static PHINode * Create(Type *Ty, unsigned NumReservedValues, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
Constructors - NumReservedValues is a hint for the number of incoming edges that this phi node will h...
FunctionCallee getOrInsertFunction(StringRef Name, FunctionType *T, AttributeList AttributeList)
Look up the specified function in the module symbol table.
Definition: Module.cpp:143
unsigned getNumIncomingValues() const
Return the number of incoming edges.
AttributeList getAttributes() const
Return the parameter attributes for this call.
Definition: InstrTypes.h:1366
static const Function * getCalledFunction(const Value *V, bool LookThroughBitCast, bool &IsNoBuiltin)
void set_subtract(const STy &S)
Compute This := This - B TODO: We should be able to use set_subtract from SetOperations.h, but SetVector interface is inconsistent with DenseSet.
Definition: SetVector.h:260
Value handle that asserts if the Value is deleted.
Definition: ValueHandle.h:237
Intrinsic::ID getIntrinsicID() const LLVM_READONLY
getIntrinsicID - This method returns the ID number of the specified function, or Intrinsic::not_intri...
Definition: Function.h:193
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
unsigned getVectorNumElements() const
Definition: DerivedTypes.h:566
static bool ClobberNonLive
A range adaptor for a pair of iterators.
Class to represent vector types.
Definition: DerivedTypes.h:432
static std::string suffixed_name_or(Value *V, StringRef Suffix, StringRef DefaultName)
const Module * getModule() const
Return the module owning the function this instruction belongs to or nullptr it the function does not...
Definition: Instruction.cpp:55
MapVector< AssertingVH< Instruction >, AssertingVH< Value > > RematerializedValueMapTy
bool isStatepointDirectiveAttr(Attribute Attr)
Return true if the Attr is an attribute that is a statepoint directive.
Definition: Statepoint.cpp:54
Optional< uint64_t > StatepointID
Definition: Statepoint.h:439
iterator_range< user_iterator > users()
Definition: Value.h:419
static const uint64_t DefaultStatepointID
Definition: Statepoint.h:441
void FoldSingleEntryPHINodes(BasicBlock *BB, MemoryDependenceResults *MemDep=nullptr)
We know that BB has one predecessor.
iterator insert(iterator I, T &&Elt)
Definition: SmallVector.h:467
const Value * getFalseValue() const
LLVM_NODISCARD bool equals(StringRef RHS) const
equals - Check for string equality, this is more efficient than compare() when the relative ordering ...
Definition: StringRef.h:174
Call sites that get wrapped by a gc.statepoint (currently only in RewriteStatepointsForGC and potenti...
Definition: Statepoint.h:437
User::op_iterator arg_begin()
Return the iterator pointing to the beginning of the argument list.
Definition: InstrTypes.h:1206
bool operator!=(uint64_t V1, const APInt &V2)
Definition: APInt.h:1977
static void CreateGCRelocates(ArrayRef< Value *> LiveVariables, const int LiveStart, ArrayRef< Value *> BasePtrs, Instruction *StatepointToken, IRBuilder<> Builder)
Helper function to place all gc relocates necessary for the given statepoint.
bool hasValue() const
Definition: Optional.h:259
unsigned getNumUses() const
This method computes the number of uses of this Value.
Definition: Value.cpp:160
bool hasGC() const
hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm to use during code generatio...
Definition: Function.h:351
static void findLiveReferences(Function &F, DominatorTree &DT, ArrayRef< CallBase *> toUpdate, MutableArrayRef< struct PartiallyConstructedSafepointRecord > records)
static cl::opt< bool > PrintLiveSetSize("spp-print-liveset-size", cl::Hidden, cl::init(false))
bool empty() const
Return true if the builder contains no target-independent attributes.
Definition: Attributes.h:828
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:55
StringRef getValueAsString() const
Return the attribute&#39;s value as a string.
Definition: Attributes.cpp:223
static VectorType * get(Type *ElementType, ElementCount EC)
This static method is the primary way to construct an VectorType.
Definition: Type.cpp:614
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:214
static bool isUnhandledGCPointerType(Type *Ty)
BasicBlock * getIncomingBlock(unsigned i) const
Return incoming basic block number i.
Function * getCalledFunction() const
Returns the function called, or null if this is an indirect function invocation.
Definition: InstrTypes.h:1287
void insertAfter(Instruction *InsertPos)
Insert an unlinked instruction into a basic block immediately after the specified instruction...
Definition: Instruction.cpp:79
unsigned pred_size(const BasicBlock *BB)
Get the number of predecessors of BB.
Definition: CFG.h:121
#define I(x, y, z)
Definition: MD5.cpp:58
bool empty() const
Determine if the SetVector is empty or not.
Definition: SetVector.h:72
static GCRegistry::Add< ErlangGC > A("erlang", "erlang-compatible garbage collector")
ModulePass class - This class is used to implement unstructured interprocedural optimizations and ana...
Definition: Pass.h:224
static void findBasePointers(const StatepointLiveSetTy &live, MapVector< Value *, Value *> &PointerToBase, DominatorTree *DT, DefiningValueMapTy &DVCache)
iterator_range< value_op_iterator > operand_values()
Definition: User.h:261
void setAttributes(AttributeList A)
Set the parameter attributes for this call.
Definition: InstrTypes.h:1370
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:332
ilist_iterator< OptionsT, !IsReverse, IsConst > getReverse() const
Get a reverse iterator to the same node.
void preserve()
Mark an analysis as preserved.
Definition: PassManager.h:174
static void insertRematerializationStores(const RematerializedValueMapTy &RematerializedValues, DenseMap< Value *, AllocaInst *> &AllocaMap, DenseSet< Value *> &VisitedLiveValues)
CallInst * CreateCall(FunctionType *FTy, Value *Callee, ArrayRef< Value *> Args=None, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:2240
static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val=0)
Return a uniquified Attribute object.
Definition: Attributes.cpp:80
size_type count(const_arg_type_t< ValueT > V) const
Return 1 if the specified key is in the set, 0 otherwise.
Definition: DenseSet.h:91
static bool insertParsePoints(Function &F, DominatorTree &DT, TargetTransformInfo &TTI, SmallVectorImpl< CallBase *> &ToUpdate)
bool removeUnreachableBlocks(Function &F, DomTreeUpdater *DTU=nullptr, MemorySSAUpdater *MSSAU=nullptr)
Remove all blocks that can not be reached from the function&#39;s entry.
Definition: Local.cpp:2214
raw_ostream & operator<<(raw_ostream &OS, const APInt &I)
Definition: APInt.h:2047
size_type count(const_arg_type_t< KeyT > Val) const
Return 1 if the specified key is in the map, 0 otherwise.
Definition: DenseMap.h:145
bool isDeclaration() const
Return true if the primary definition of this global value is outside of the current translation unit...
Definition: Globals.cpp:231
Analysis pass providing the TargetLibraryInfo.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
Represents calls to the gc.relocate intrinsic.
Definition: Statepoint.h:360
Mark the deopt arguments associated with the statepoint as only being "live-in".
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:575
LLVM Value Representation.
Definition: Value.h:73
A vector that has set insertion semantics.
Definition: SetVector.h:40
succ_range successors(Instruction *I)
Definition: CFG.h:259
static const Function * getParent(const Value *V)
AttributeSet getFnAttributes() const
The function attributes are returned.
Attribute getFnAttribute(Attribute::AttrKind Kind) const
Return the attribute for the given attribute kind.
Definition: Function.h:333
MapVector< BasicBlock *, SetVector< Value * > > LiveOut
Values live out of this basic block (i.e.
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
void PromoteMemToReg(ArrayRef< AllocaInst *> Allocas, DominatorTree &DT, AssumptionCache *AC=nullptr)
Promote the specified list of alloca instructions into scalar registers, inserting PHI nodes as appro...
Invoke instruction.
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
inst_range instructions(Function *F)
Definition: InstIterator.h:133
A container for analyses that lazily runs them and caches their results.
const LandingPadInst * getLandingPadInst() const
Return the landingpad instruction associated with the landing pad.
Definition: BasicBlock.cpp:475
Legacy analysis pass which computes a DominatorTree.
Definition: Dominators.h:259
This pass exposes codegen information to IR-level passes.
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1975
MapVector< Value *, Value * > PointerToBase
Mapping from live pointers to a base-defining-value.
void setIncomingValue(unsigned i, Value *V)
static void analyzeParsePointLiveness(DominatorTree &DT, GCPtrLivenessData &OriginalLivenessData, CallBase *Call, PartiallyConstructedSafepointRecord &Result)
static ExtractElementInst * Create(Value *Vec, Value *Idx, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
#define LLVM_DEBUG(X)
Definition: Debug.h:122
bool isEmpty() const
Return true if there are no attributes.
Definition: Attributes.h:669
InstListType::reverse_iterator reverse_iterator
Definition: BasicBlock.h:91
MDNode * createMutableTBAAAccessTag(MDNode *Tag)
Return mutable version of the given mutable or immutable TBAA access tag.
Definition: MDBuilder.cpp:278
bool use_empty() const
Definition: Value.h:342
LocationClass< Ty > location(Ty &L)
Definition: CommandLine.h:448
static AttributeList get(LLVMContext &C, ArrayRef< std::pair< unsigned, Attribute >> Attrs)
Create an AttributeList with the specified parameters in it.
Definition: Attributes.cpp:973
iterator_range< arg_iterator > args()
Definition: Function.h:719
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:143
A wrapper class for inspecting calls to intrinsic functions.
Definition: IntrinsicInst.h:43
const BasicBlock * getParent() const
Definition: Instruction.h:66
an instruction to allocate memory on the stack
Definition: Instructions.h:59
static BaseDefiningValueResult findBaseDefiningValue(Value *I)
Helper function for findBasePointer - Will return a value which either a) defines the base pointer fo...
An analysis over an "outer" IR unit that provides access to an analysis manager over an "inner" IR un...
Definition: PassManager.h:1044
bool is_contained(R &&Range, const E &Element)
Wrapper function around std::find to detect if an element exists in a container.
Definition: STLExtras.h:1224
unsigned gcArgsStartIdx() const
Definition: Statepoint.h:244