1 //===-- llvm/IR/Statepoint.h - gc.statepoint utilities ------ --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains utility functions and a wrapper class analogous to
11 // CallSite for accessing the fields of gc.statepoint, gc.relocate,
12 // gc.result intrinsics; and some general utilities helpful when dealing with
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_IR_STATEPOINT_H
18 #define LLVM_IR_STATEPOINT_H
20 #include "llvm/ADT/iterator_range.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/IR/BasicBlock.h"
23 #include "llvm/IR/CallSite.h"
24 #include "llvm/IR/Constants.h"
25 #include "llvm/IR/Function.h"
26 #include "llvm/IR/Instructions.h"
27 #include "llvm/IR/IntrinsicInst.h"
28 #include "llvm/IR/Intrinsics.h"
31 /// The statepoint intrinsic accepts a set of flags as its third argument.
32 /// Valid values come out of this set.
33 enum class StatepointFlags {
35 GCTransition = 1, ///< Indicates that this statepoint is a transition from
36 ///< GC-aware code to code that is not GC-aware.
38 MaskAll = GCTransition ///< A bitmask that includes all valid flags.
43 class ImmutableStatepoint;
45 bool isStatepoint(ImmutableCallSite CS);
46 bool isStatepoint(const Value *V);
47 bool isStatepoint(const Value &V);
49 bool isGCRelocate(ImmutableCallSite CS);
50 bool isGCResult(ImmutableCallSite CS);
52 /// Analogous to CallSiteBase, this provides most of the actual
53 /// functionality for Statepoint and ImmutableStatepoint. It is
54 /// templatized to allow easily specializing of const and non-const
55 /// concrete subtypes. This is structured analogous to CallSite
56 /// rather than the IntrinsicInst.h helpers since we need to support
57 /// invokable statepoints.
58 template <typename FunTy, typename InstructionTy, typename ValueTy,
60 class StatepointBase {
61 CallSiteTy StatepointCS;
62 void *operator new(size_t, unsigned) = delete;
63 void *operator new(size_t s) = delete;
66 explicit StatepointBase(InstructionTy *I) {
67 if (isStatepoint(I)) {
68 StatepointCS = CallSiteTy(I);
69 assert(StatepointCS && "isStatepoint implies CallSite");
72 explicit StatepointBase(CallSiteTy CS) {
78 typedef typename CallSiteTy::arg_iterator arg_iterator;
83 CalledFunctionPos = 2,
89 explicit operator bool() const {
90 // We do not assign non-statepoint CallSites to StatepointCS.
91 return (bool)StatepointCS;
94 /// Return the underlying CallSite.
95 CallSiteTy getCallSite() const {
96 assert(*this && "check validity first!");
100 uint64_t getFlags() const {
101 return cast<ConstantInt>(getCallSite().getArgument(FlagsPos))
105 /// Return the ID associated with this statepoint.
106 uint64_t getID() const {
107 const Value *IDVal = getCallSite().getArgument(IDPos);
108 return cast<ConstantInt>(IDVal)->getZExtValue();
111 /// Return the number of patchable bytes associated with this statepoint.
112 uint32_t getNumPatchBytes() const {
113 const Value *NumPatchBytesVal = getCallSite().getArgument(NumPatchBytesPos);
114 uint64_t NumPatchBytes =
115 cast<ConstantInt>(NumPatchBytesVal)->getZExtValue();
116 assert(isInt<32>(NumPatchBytes) && "should fit in 32 bits!");
117 return NumPatchBytes;
120 /// Return the value actually being called or invoked.
121 ValueTy *getCalledValue() const {
122 return getCallSite().getArgument(CalledFunctionPos);
125 InstructionTy *getInstruction() const {
126 return getCallSite().getInstruction();
129 /// Return the function being called if this is a direct call, otherwise
130 /// return null (if it's an indirect call).
131 FunTy *getCalledFunction() const {
132 return dyn_cast<Function>(getCalledValue());
135 /// Return the caller function for this statepoint.
136 FunTy *getCaller() const { return getCallSite().getCaller(); }
138 /// Determine if the statepoint cannot unwind.
139 bool doesNotThrow() const {
140 Function *F = getCalledFunction();
141 return getCallSite().doesNotThrow() || (F ? F->doesNotThrow() : false);
144 /// Return the type of the value returned by the call underlying the
146 Type *getActualReturnType() const {
147 auto *FTy = cast<FunctionType>(
148 cast<PointerType>(getCalledValue()->getType())->getElementType());
149 return FTy->getReturnType();
152 /// Number of arguments to be passed to the actual callee.
153 int getNumCallArgs() const {
154 const Value *NumCallArgsVal = getCallSite().getArgument(NumCallArgsPos);
155 return cast<ConstantInt>(NumCallArgsVal)->getZExtValue();
158 size_t arg_size() const { return getNumCallArgs(); }
159 typename CallSiteTy::arg_iterator arg_begin() const {
160 assert(CallArgsBeginPos <= (int)getCallSite().arg_size());
161 return getCallSite().arg_begin() + CallArgsBeginPos;
163 typename CallSiteTy::arg_iterator arg_end() const {
164 auto I = arg_begin() + arg_size();
165 assert((getCallSite().arg_end() - I) >= 0);
169 ValueTy *getArgument(unsigned Index) {
170 assert(Index < arg_size() && "out of bounds!");
171 return *(arg_begin() + Index);
174 /// range adapter for call arguments
175 iterator_range<arg_iterator> call_args() const {
176 return make_range(arg_begin(), arg_end());
179 /// \brief Return true if the call or the callee has the given attribute.
180 bool paramHasAttr(unsigned i, Attribute::AttrKind A) const {
181 Function *F = getCalledFunction();
182 return getCallSite().paramHasAttr(i + CallArgsBeginPos, A) ||
183 (F ? F->getAttributes().hasAttribute(i, A) : false);
186 /// Number of GC transition args.
187 int getNumTotalGCTransitionArgs() const {
188 const Value *NumGCTransitionArgs = *arg_end();
189 return cast<ConstantInt>(NumGCTransitionArgs)->getZExtValue();
191 typename CallSiteTy::arg_iterator gc_transition_args_begin() const {
192 auto I = arg_end() + 1;
193 assert((getCallSite().arg_end() - I) >= 0);
196 typename CallSiteTy::arg_iterator gc_transition_args_end() const {
197 auto I = gc_transition_args_begin() + getNumTotalGCTransitionArgs();
198 assert((getCallSite().arg_end() - I) >= 0);
202 /// range adapter for GC transition arguments
203 iterator_range<arg_iterator> gc_transition_args() const {
204 return make_range(gc_transition_args_begin(), gc_transition_args_end());
207 /// Number of additional arguments excluding those intended
208 /// for garbage collection.
209 int getNumTotalVMSArgs() const {
210 const Value *NumVMSArgs = *gc_transition_args_end();
211 return cast<ConstantInt>(NumVMSArgs)->getZExtValue();
214 typename CallSiteTy::arg_iterator vm_state_begin() const {
215 auto I = gc_transition_args_end() + 1;
216 assert((getCallSite().arg_end() - I) >= 0);
219 typename CallSiteTy::arg_iterator vm_state_end() const {
220 auto I = vm_state_begin() + getNumTotalVMSArgs();
221 assert((getCallSite().arg_end() - I) >= 0);
225 /// range adapter for vm state arguments
226 iterator_range<arg_iterator> vm_state_args() const {
227 return make_range(vm_state_begin(), vm_state_end());
230 typename CallSiteTy::arg_iterator gc_args_begin() const {
231 return vm_state_end();
233 typename CallSiteTy::arg_iterator gc_args_end() const {
234 return getCallSite().arg_end();
237 unsigned gcArgsStartIdx() const {
238 return gc_args_begin() - getInstruction()->op_begin();
241 /// range adapter for gc arguments
242 iterator_range<arg_iterator> gc_args() const {
243 return make_range(gc_args_begin(), gc_args_end());
246 /// Get list of all gc reloactes linked to this statepoint
247 /// May contain several relocations for the same base/derived pair.
248 /// For example this could happen due to relocations on unwinding
250 std::vector<const GCRelocateInst *> getRelocates() const;
252 /// Get the experimental_gc_result call tied to this statepoint. Can be
253 /// nullptr if there isn't a gc_result tied to this statepoint. Guaranteed to
254 /// be a CallInst if non-null.
255 const GCResultInst *getGCResult() const {
256 for (auto *U : getInstruction()->users())
257 if (auto *GRI = dyn_cast<GCResultInst>(U))
263 /// Asserts if this statepoint is malformed. Common cases for failure
264 /// include incorrect length prefixes for variable length sections or
265 /// illegal values for parameters.
267 assert(getNumCallArgs() >= 0 &&
268 "number of arguments to actually callee can't be negative");
270 // The internal asserts in the iterator accessors do the rest.
273 (void)gc_transition_args_begin();
274 (void)gc_transition_args_end();
275 (void)vm_state_begin();
276 (void)vm_state_end();
277 (void)gc_args_begin();
283 /// A specialization of it's base class for read only access
284 /// to a gc.statepoint.
285 class ImmutableStatepoint
286 : public StatepointBase<const Function, const Instruction, const Value,
288 typedef StatepointBase<const Function, const Instruction, const Value,
289 ImmutableCallSite> Base;
292 explicit ImmutableStatepoint(const Instruction *I) : Base(I) {}
293 explicit ImmutableStatepoint(ImmutableCallSite CS) : Base(CS) {}
296 /// A specialization of it's base class for read-write access
297 /// to a gc.statepoint.
299 : public StatepointBase<Function, Instruction, Value, CallSite> {
300 typedef StatepointBase<Function, Instruction, Value, CallSite> Base;
303 explicit Statepoint(Instruction *I) : Base(I) {}
304 explicit Statepoint(CallSite CS) : Base(CS) {}
307 /// Common base class for representing values projected from a statepoint.
308 /// Currently, the only projections available are gc.result and gc.relocate.
309 class GCProjectionInst : public IntrinsicInst {
311 static inline bool classof(const IntrinsicInst *I) {
312 return I->getIntrinsicID() == Intrinsic::experimental_gc_relocate ||
313 I->getIntrinsicID() == Intrinsic::experimental_gc_result;
315 static inline bool classof(const Value *V) {
316 return isa<IntrinsicInst>(V) && classof(cast<IntrinsicInst>(V));
319 /// Return true if this relocate is tied to the invoke statepoint.
320 /// This includes relocates which are on the unwinding path.
321 bool isTiedToInvoke() const {
322 const Value *Token = getArgOperand(0);
324 return isa<LandingPadInst>(Token) || isa<InvokeInst>(Token);
327 /// The statepoint with which this gc.relocate is associated.
328 const Instruction *getStatepoint() const {
329 const Value *Token = getArgOperand(0);
331 // This takes care both of relocates for call statepoints and relocates
332 // on normal path of invoke statepoint.
333 if (!isa<LandingPadInst>(Token)) {
334 assert(isStatepoint(Token));
335 return cast<Instruction>(Token);
338 // This relocate is on exceptional path of an invoke statepoint
339 const BasicBlock *InvokeBB =
340 cast<Instruction>(Token)->getParent()->getUniquePredecessor();
342 assert(InvokeBB && "safepoints should have unique landingpads");
343 assert(InvokeBB->getTerminator() &&
344 "safepoint block should be well formed");
345 assert(isStatepoint(InvokeBB->getTerminator()));
347 return InvokeBB->getTerminator();
351 /// Represents calls to the gc.relocate intrinsic.
352 class GCRelocateInst : public GCProjectionInst {
354 static inline bool classof(const IntrinsicInst *I) {
355 return I->getIntrinsicID() == Intrinsic::experimental_gc_relocate;
357 static inline bool classof(const Value *V) {
358 return isa<IntrinsicInst>(V) && classof(cast<IntrinsicInst>(V));
361 /// The index into the associate statepoint's argument list
362 /// which contains the base pointer of the pointer whose
363 /// relocation this gc.relocate describes.
364 unsigned getBasePtrIndex() const {
365 return cast<ConstantInt>(getArgOperand(1))->getZExtValue();
368 /// The index into the associate statepoint's argument list which
369 /// contains the pointer whose relocation this gc.relocate describes.
370 unsigned getDerivedPtrIndex() const {
371 return cast<ConstantInt>(getArgOperand(2))->getZExtValue();
374 Value *getBasePtr() const {
375 ImmutableCallSite CS(getStatepoint());
376 return *(CS.arg_begin() + getBasePtrIndex());
379 Value *getDerivedPtr() const {
380 ImmutableCallSite CS(getStatepoint());
381 return *(CS.arg_begin() + getDerivedPtrIndex());
385 /// Represents calls to the gc.result intrinsic.
386 class GCResultInst : public GCProjectionInst {
388 static inline bool classof(const IntrinsicInst *I) {
389 return I->getIntrinsicID() == Intrinsic::experimental_gc_result;
391 static inline bool classof(const Value *V) {
392 return isa<IntrinsicInst>(V) && classof(cast<IntrinsicInst>(V));
396 template <typename FunTy, typename InstructionTy, typename ValueTy,
398 std::vector<const GCRelocateInst *>
399 StatepointBase<FunTy, InstructionTy, ValueTy, CallSiteTy>::getRelocates()
402 std::vector<const GCRelocateInst *> Result;
404 CallSiteTy StatepointCS = getCallSite();
406 // Search for relocated pointers. Note that working backwards from the
407 // gc_relocates ensures that we only get pairs which are actually relocated
408 // and used after the statepoint.
409 for (const User *U : getInstruction()->users())
410 if (auto *Relocate = dyn_cast<GCRelocateInst>(U))
411 Result.push_back(Relocate);
413 if (!StatepointCS.isInvoke())
416 // We need to scan thorough exceptional relocations if it is invoke statepoint
417 LandingPadInst *LandingPad =
418 cast<InvokeInst>(getInstruction())->getLandingPadInst();
420 // Search for gc relocates that are attached to this landingpad.
421 for (const User *LandingPadUser : LandingPad->users()) {
422 if (auto *Relocate = dyn_cast<GCRelocateInst>(LandingPadUser))
423 Result.push_back(Relocate);
428 /// Call sites that get wrapped by a gc.statepoint (currently only in
429 /// RewriteStatepointsForGC and potentially in other passes in the future) can
430 /// have attributes that describe properties of gc.statepoint call they will be
431 /// eventually be wrapped in. This struct is used represent such directives.
432 struct StatepointDirectives {
433 Optional<uint32_t> NumPatchBytes;
434 Optional<uint64_t> StatepointID;
436 static const uint64_t DefaultStatepointID = 0xABCDEF00;
437 static const uint64_t DeoptBundleStatepointID = 0xABCDEF0F;
440 /// Parse out statepoint directives from the function attributes present in \p
442 StatepointDirectives parseStatepointDirectivesFromAttrs(AttributeSet AS);
444 /// Return \c true if the the \p Attr is an attribute that is a statepoint
446 bool isStatepointDirectiveAttr(Attribute Attr);