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Diffstat (limited to 'clang-r353983e/include/llvm/Transforms/Utils/Cloning.h')
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diff --git a/clang-r353983e/include/llvm/Transforms/Utils/Cloning.h b/clang-r353983e/include/llvm/Transforms/Utils/Cloning.h new file mode 100644 index 00000000..86775b1a --- /dev/null +++ b/clang-r353983e/include/llvm/Transforms/Utils/Cloning.h @@ -0,0 +1,280 @@ +//===- Cloning.h - Clone various parts of LLVM programs ---------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file defines various functions that are used to clone chunks of LLVM +// code for various purposes. This varies from copying whole modules into new +// modules, to cloning functions with different arguments, to inlining +// functions, to copying basic blocks to support loop unrolling or superblock +// formation, etc. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TRANSFORMS_UTILS_CLONING_H +#define LLVM_TRANSFORMS_UTILS_CLONING_H + +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/Twine.h" +#include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/AssumptionCache.h" +#include "llvm/Analysis/InlineCost.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/ValueHandle.h" +#include "llvm/Transforms/Utils/ValueMapper.h" +#include <functional> +#include <memory> +#include <vector> + +namespace llvm { + +class AllocaInst; +class BasicBlock; +class BlockFrequencyInfo; +class CallInst; +class CallGraph; +class DebugInfoFinder; +class DominatorTree; +class Function; +class Instruction; +class InvokeInst; +class Loop; +class LoopInfo; +class Module; +class ProfileSummaryInfo; +class ReturnInst; +class DomTreeUpdater; + +/// Return an exact copy of the specified module +std::unique_ptr<Module> CloneModule(const Module &M); +std::unique_ptr<Module> CloneModule(const Module &M, ValueToValueMapTy &VMap); + +/// Return a copy of the specified module. The ShouldCloneDefinition function +/// controls whether a specific GlobalValue's definition is cloned. If the +/// function returns false, the module copy will contain an external reference +/// in place of the global definition. +std::unique_ptr<Module> +CloneModule(const Module &M, ValueToValueMapTy &VMap, + function_ref<bool(const GlobalValue *)> ShouldCloneDefinition); + +/// This struct can be used to capture information about code +/// being cloned, while it is being cloned. +struct ClonedCodeInfo { + /// This is set to true if the cloned code contains a normal call instruction. + bool ContainsCalls = false; + + /// This is set to true if the cloned code contains a 'dynamic' alloca. + /// Dynamic allocas are allocas that are either not in the entry block or they + /// are in the entry block but are not a constant size. + bool ContainsDynamicAllocas = false; + + /// All cloned call sites that have operand bundles attached are appended to + /// this vector. This vector may contain nulls or undefs if some of the + /// originally inserted callsites were DCE'ed after they were cloned. + std::vector<WeakTrackingVH> OperandBundleCallSites; + + ClonedCodeInfo() = default; +}; + +/// Return a copy of the specified basic block, but without +/// embedding the block into a particular function. The block returned is an +/// exact copy of the specified basic block, without any remapping having been +/// performed. Because of this, this is only suitable for applications where +/// the basic block will be inserted into the same function that it was cloned +/// from (loop unrolling would use this, for example). +/// +/// Also, note that this function makes a direct copy of the basic block, and +/// can thus produce illegal LLVM code. In particular, it will copy any PHI +/// nodes from the original block, even though there are no predecessors for the +/// newly cloned block (thus, phi nodes will have to be updated). Also, this +/// block will branch to the old successors of the original block: these +/// successors will have to have any PHI nodes updated to account for the new +/// incoming edges. +/// +/// The correlation between instructions in the source and result basic blocks +/// is recorded in the VMap map. +/// +/// If you have a particular suffix you'd like to use to add to any cloned +/// names, specify it as the optional third parameter. +/// +/// If you would like the basic block to be auto-inserted into the end of a +/// function, you can specify it as the optional fourth parameter. +/// +/// If you would like to collect additional information about the cloned +/// function, you can specify a ClonedCodeInfo object with the optional fifth +/// parameter. +BasicBlock *CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap, + const Twine &NameSuffix = "", Function *F = nullptr, + ClonedCodeInfo *CodeInfo = nullptr, + DebugInfoFinder *DIFinder = nullptr); + +/// Return a copy of the specified function and add it to that +/// function's module. Also, any references specified in the VMap are changed +/// to refer to their mapped value instead of the original one. If any of the +/// arguments to the function are in the VMap, the arguments are deleted from +/// the resultant function. The VMap is updated to include mappings from all of +/// the instructions and basicblocks in the function from their old to new +/// values. The final argument captures information about the cloned code if +/// non-null. +/// +/// VMap contains no non-identity GlobalValue mappings and debug info metadata +/// will not be cloned. +/// +Function *CloneFunction(Function *F, ValueToValueMapTy &VMap, + ClonedCodeInfo *CodeInfo = nullptr); + +/// Clone OldFunc into NewFunc, transforming the old arguments into references +/// to VMap values. Note that if NewFunc already has basic blocks, the ones +/// cloned into it will be added to the end of the function. This function +/// fills in a list of return instructions, and can optionally remap types +/// and/or append the specified suffix to all values cloned. +/// +/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue +/// mappings. +/// +void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, + ValueToValueMapTy &VMap, bool ModuleLevelChanges, + SmallVectorImpl<ReturnInst*> &Returns, + const char *NameSuffix = "", + ClonedCodeInfo *CodeInfo = nullptr, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr); + +void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc, + const Instruction *StartingInst, + ValueToValueMapTy &VMap, bool ModuleLevelChanges, + SmallVectorImpl<ReturnInst *> &Returns, + const char *NameSuffix = "", + ClonedCodeInfo *CodeInfo = nullptr); + +/// This works exactly like CloneFunctionInto, +/// except that it does some simple constant prop and DCE on the fly. The +/// effect of this is to copy significantly less code in cases where (for +/// example) a function call with constant arguments is inlined, and those +/// constant arguments cause a significant amount of code in the callee to be +/// dead. Since this doesn't produce an exactly copy of the input, it can't be +/// used for things like CloneFunction or CloneModule. +/// +/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue +/// mappings. +/// +void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, + ValueToValueMapTy &VMap, bool ModuleLevelChanges, + SmallVectorImpl<ReturnInst*> &Returns, + const char *NameSuffix = "", + ClonedCodeInfo *CodeInfo = nullptr, + Instruction *TheCall = nullptr); + +/// This class captures the data input to the InlineFunction call, and records +/// the auxiliary results produced by it. +class InlineFunctionInfo { +public: + explicit InlineFunctionInfo(CallGraph *cg = nullptr, + std::function<AssumptionCache &(Function &)> + *GetAssumptionCache = nullptr, + ProfileSummaryInfo *PSI = nullptr, + BlockFrequencyInfo *CallerBFI = nullptr, + BlockFrequencyInfo *CalleeBFI = nullptr) + : CG(cg), GetAssumptionCache(GetAssumptionCache), PSI(PSI), + CallerBFI(CallerBFI), CalleeBFI(CalleeBFI) {} + + /// If non-null, InlineFunction will update the callgraph to reflect the + /// changes it makes. + CallGraph *CG; + std::function<AssumptionCache &(Function &)> *GetAssumptionCache; + ProfileSummaryInfo *PSI; + BlockFrequencyInfo *CallerBFI, *CalleeBFI; + + /// InlineFunction fills this in with all static allocas that get copied into + /// the caller. + SmallVector<AllocaInst *, 4> StaticAllocas; + + /// InlineFunction fills this in with callsites that were inlined from the + /// callee. This is only filled in if CG is non-null. + SmallVector<WeakTrackingVH, 8> InlinedCalls; + + /// All of the new call sites inlined into the caller. + /// + /// 'InlineFunction' fills this in by scanning the inlined instructions, and + /// only if CG is null. If CG is non-null, instead the value handle + /// `InlinedCalls` above is used. + SmallVector<CallSite, 8> InlinedCallSites; + + void reset() { + StaticAllocas.clear(); + InlinedCalls.clear(); + InlinedCallSites.clear(); + } +}; + +/// This function inlines the called function into the basic +/// block of the caller. This returns false if it is not possible to inline +/// this call. The program is still in a well defined state if this occurs +/// though. +/// +/// Note that this only does one level of inlining. For example, if the +/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now +/// exists in the instruction stream. Similarly this will inline a recursive +/// function by one level. +/// +/// Note that while this routine is allowed to cleanup and optimize the +/// *inlined* code to minimize the actual inserted code, it must not delete +/// code in the caller as users of this routine may have pointers to +/// instructions in the caller that need to remain stable. +/// +/// If ForwardVarArgsTo is passed, inlining a function with varargs is allowed +/// and all varargs at the callsite will be passed to any calls to +/// ForwardVarArgsTo. The caller of InlineFunction has to make sure any varargs +/// are only used by ForwardVarArgsTo. +InlineResult InlineFunction(CallInst *C, InlineFunctionInfo &IFI, + AAResults *CalleeAAR = nullptr, + bool InsertLifetime = true); +InlineResult InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, + AAResults *CalleeAAR = nullptr, + bool InsertLifetime = true); +InlineResult InlineFunction(CallSite CS, InlineFunctionInfo &IFI, + AAResults *CalleeAAR = nullptr, + bool InsertLifetime = true, + Function *ForwardVarArgsTo = nullptr); + +/// Clones a loop \p OrigLoop. Returns the loop and the blocks in \p +/// Blocks. +/// +/// Updates LoopInfo and DominatorTree assuming the loop is dominated by block +/// \p LoopDomBB. Insert the new blocks before block specified in \p Before. +/// Note: Only innermost loops are supported. +Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB, + Loop *OrigLoop, ValueToValueMapTy &VMap, + const Twine &NameSuffix, LoopInfo *LI, + DominatorTree *DT, + SmallVectorImpl<BasicBlock *> &Blocks); + +/// Remaps instructions in \p Blocks using the mapping in \p VMap. +void remapInstructionsInBlocks(const SmallVectorImpl<BasicBlock *> &Blocks, + ValueToValueMapTy &VMap); + +/// Split edge between BB and PredBB and duplicate all non-Phi instructions +/// from BB between its beginning and the StopAt instruction into the split +/// block. Phi nodes are not duplicated, but their uses are handled correctly: +/// we replace them with the uses of corresponding Phi inputs. ValueMapping +/// is used to map the original instructions from BB to their newly-created +/// copies. Returns the split block. +BasicBlock *DuplicateInstructionsInSplitBetween(BasicBlock *BB, + BasicBlock *PredBB, + Instruction *StopAt, + ValueToValueMapTy &ValueMapping, + DomTreeUpdater &DTU); + +/// Updates profile information by adjusting the entry count by adding +/// entryDelta then scaling callsite information by the new count divided by the +/// old count. VMap is used during inlinng to also update the new clone +void updateProfileCallee( + Function *Callee, int64_t entryDelta, + const ValueMap<const Value *, WeakTrackingVH> *VMap = nullptr); + +} // end namespace llvm + +#endif // LLVM_TRANSFORMS_UTILS_CLONING_H |