diff options
| author | Stephen Hines <srhines@google.com> | 2019-07-02 16:25:20 -0700 |
|---|---|---|
| committer | Ali B <abittin@gmail.com> | 2019-07-05 19:33:16 +0300 |
| commit | 9afee4e65dc5f9f5eb371683729ff67b8df81d03 (patch) | |
| tree | 4cf241d6c9044f91ee8c06e6920174d06f8de0b6 /clang-r353983e/include/llvm/Transforms/Utils/PredicateInfo.h | |
| parent | 2f19bd722c4c825320d1511c1ed83161b7f95d51 (diff) | |
clang 9.0.5 (based on r353983e) from build 5696680.
Bug: http://b/135931688
Bug: http://b/136008926
Test: N/A
Change-Id: I922d17410047d2e2df4625615352c588ee71b203
Diffstat (limited to 'clang-r353983e/include/llvm/Transforms/Utils/PredicateInfo.h')
| -rw-r--r-- | clang-r353983e/include/llvm/Transforms/Utils/PredicateInfo.h | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/clang-r353983e/include/llvm/Transforms/Utils/PredicateInfo.h b/clang-r353983e/include/llvm/Transforms/Utils/PredicateInfo.h new file mode 100644 index 00000000..da4a5dcc --- /dev/null +++ b/clang-r353983e/include/llvm/Transforms/Utils/PredicateInfo.h @@ -0,0 +1,298 @@ +//===- PredicateInfo.h - Build PredicateInfo ----------------------*-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 +// +//===----------------------------------------------------------------------===// +/// +/// \file +/// This file implements the PredicateInfo analysis, which creates an Extended +/// SSA form for operations used in branch comparisons and llvm.assume +/// comparisons. +/// +/// Copies of these operations are inserted into the true/false edge (and after +/// assumes), and information attached to the copies. All uses of the original +/// operation in blocks dominated by the true/false edge (and assume), are +/// replaced with uses of the copies. This enables passes to easily and sparsely +/// propagate condition based info into the operations that may be affected. +/// +/// Example: +/// %cmp = icmp eq i32 %x, 50 +/// br i1 %cmp, label %true, label %false +/// true: +/// ret i32 %x +/// false: +/// ret i32 1 +/// +/// will become +/// +/// %cmp = icmp eq i32, %x, 50 +/// br i1 %cmp, label %true, label %false +/// true: +/// %x.0 = call \@llvm.ssa_copy.i32(i32 %x) +/// ret i32 %x.0 +/// false: +/// ret i32 1 +/// +/// Using getPredicateInfoFor on x.0 will give you the comparison it is +/// dominated by (the icmp), and that you are located in the true edge of that +/// comparison, which tells you x.0 is 50. +/// +/// In order to reduce the number of copies inserted, predicateinfo is only +/// inserted where it would actually be live. This means if there are no uses of +/// an operation dominated by the branch edges, or by an assume, the associated +/// predicate info is never inserted. +/// +/// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TRANSFORMS_UTILS_PREDICATEINFO_H +#define LLVM_TRANSFORMS_UTILS_PREDICATEINFO_H + +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/DenseSet.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallSet.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/ilist.h" +#include "llvm/ADT/ilist_node.h" +#include "llvm/ADT/iterator.h" +#include "llvm/Analysis/AssumptionCache.h" +#include "llvm/Analysis/OrderedInstructions.h" +#include "llvm/IR/BasicBlock.h" +#include "llvm/IR/Dominators.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/Module.h" +#include "llvm/IR/OperandTraits.h" +#include "llvm/IR/Type.h" +#include "llvm/IR/Use.h" +#include "llvm/IR/User.h" +#include "llvm/IR/Value.h" +#include "llvm/IR/ValueHandle.h" +#include "llvm/Pass.h" +#include "llvm/PassAnalysisSupport.h" +#include "llvm/Support/Casting.h" +#include "llvm/Support/Compiler.h" +#include "llvm/Support/ErrorHandling.h" +#include <algorithm> +#include <cassert> +#include <cstddef> +#include <iterator> +#include <memory> +#include <utility> + +namespace llvm { + +class DominatorTree; +class Function; +class Instruction; +class MemoryAccess; +class LLVMContext; +class raw_ostream; + +enum PredicateType { PT_Branch, PT_Assume, PT_Switch }; + +// Base class for all predicate information we provide. +// All of our predicate information has at least a comparison. +class PredicateBase : public ilist_node<PredicateBase> { +public: + PredicateType Type; + // The original operand before we renamed it. + // This can be use by passes, when destroying predicateinfo, to know + // whether they can just drop the intrinsic, or have to merge metadata. + Value *OriginalOp; + PredicateBase(const PredicateBase &) = delete; + PredicateBase &operator=(const PredicateBase &) = delete; + PredicateBase() = delete; + virtual ~PredicateBase() = default; + +protected: + PredicateBase(PredicateType PT, Value *Op) : Type(PT), OriginalOp(Op) {} +}; + +class PredicateWithCondition : public PredicateBase { +public: + Value *Condition; + static bool classof(const PredicateBase *PB) { + return PB->Type == PT_Assume || PB->Type == PT_Branch || + PB->Type == PT_Switch; + } + +protected: + PredicateWithCondition(PredicateType PT, Value *Op, Value *Condition) + : PredicateBase(PT, Op), Condition(Condition) {} +}; + +// Provides predicate information for assumes. Since assumes are always true, +// we simply provide the assume instruction, so you can tell your relative +// position to it. +class PredicateAssume : public PredicateWithCondition { +public: + IntrinsicInst *AssumeInst; + PredicateAssume(Value *Op, IntrinsicInst *AssumeInst, Value *Condition) + : PredicateWithCondition(PT_Assume, Op, Condition), + AssumeInst(AssumeInst) {} + PredicateAssume() = delete; + static bool classof(const PredicateBase *PB) { + return PB->Type == PT_Assume; + } +}; + +// Mixin class for edge predicates. The FROM block is the block where the +// predicate originates, and the TO block is the block where the predicate is +// valid. +class PredicateWithEdge : public PredicateWithCondition { +public: + BasicBlock *From; + BasicBlock *To; + PredicateWithEdge() = delete; + static bool classof(const PredicateBase *PB) { + return PB->Type == PT_Branch || PB->Type == PT_Switch; + } + +protected: + PredicateWithEdge(PredicateType PType, Value *Op, BasicBlock *From, + BasicBlock *To, Value *Cond) + : PredicateWithCondition(PType, Op, Cond), From(From), To(To) {} +}; + +// Provides predicate information for branches. +class PredicateBranch : public PredicateWithEdge { +public: + // If true, SplitBB is the true successor, otherwise it's the false successor. + bool TrueEdge; + PredicateBranch(Value *Op, BasicBlock *BranchBB, BasicBlock *SplitBB, + Value *Condition, bool TakenEdge) + : PredicateWithEdge(PT_Branch, Op, BranchBB, SplitBB, Condition), + TrueEdge(TakenEdge) {} + PredicateBranch() = delete; + static bool classof(const PredicateBase *PB) { + return PB->Type == PT_Branch; + } +}; + +class PredicateSwitch : public PredicateWithEdge { +public: + Value *CaseValue; + // This is the switch instruction. + SwitchInst *Switch; + PredicateSwitch(Value *Op, BasicBlock *SwitchBB, BasicBlock *TargetBB, + Value *CaseValue, SwitchInst *SI) + : PredicateWithEdge(PT_Switch, Op, SwitchBB, TargetBB, + SI->getCondition()), + CaseValue(CaseValue), Switch(SI) {} + PredicateSwitch() = delete; + static bool classof(const PredicateBase *PB) { + return PB->Type == PT_Switch; + } +}; + +// This name is used in a few places, so kick it into their own namespace +namespace PredicateInfoClasses { +struct ValueDFS; +} + +/// Encapsulates PredicateInfo, including all data associated with memory +/// accesses. +class PredicateInfo { +private: + // Used to store information about each value we might rename. + struct ValueInfo { + // Information about each possible copy. During processing, this is each + // inserted info. After processing, we move the uninserted ones to the + // uninserted vector. + SmallVector<PredicateBase *, 4> Infos; + SmallVector<PredicateBase *, 4> UninsertedInfos; + }; + // This owns the all the predicate infos in the function, placed or not. + iplist<PredicateBase> AllInfos; + +public: + PredicateInfo(Function &, DominatorTree &, AssumptionCache &); + ~PredicateInfo(); + + void verifyPredicateInfo() const; + + void dump() const; + void print(raw_ostream &) const; + + const PredicateBase *getPredicateInfoFor(const Value *V) const { + return PredicateMap.lookup(V); + } + +protected: + // Used by PredicateInfo annotater, dumpers, and wrapper pass. + friend class PredicateInfoAnnotatedWriter; + friend class PredicateInfoPrinterLegacyPass; + +private: + void buildPredicateInfo(); + void processAssume(IntrinsicInst *, BasicBlock *, SmallPtrSetImpl<Value *> &); + void processBranch(BranchInst *, BasicBlock *, SmallPtrSetImpl<Value *> &); + void processSwitch(SwitchInst *, BasicBlock *, SmallPtrSetImpl<Value *> &); + void renameUses(SmallPtrSetImpl<Value *> &); + using ValueDFS = PredicateInfoClasses::ValueDFS; + typedef SmallVectorImpl<ValueDFS> ValueDFSStack; + void convertUsesToDFSOrdered(Value *, SmallVectorImpl<ValueDFS> &); + Value *materializeStack(unsigned int &, ValueDFSStack &, Value *); + bool stackIsInScope(const ValueDFSStack &, const ValueDFS &) const; + void popStackUntilDFSScope(ValueDFSStack &, const ValueDFS &); + ValueInfo &getOrCreateValueInfo(Value *); + void addInfoFor(SmallPtrSetImpl<Value *> &OpsToRename, Value *Op, + PredicateBase *PB); + const ValueInfo &getValueInfo(Value *) const; + Function &F; + DominatorTree &DT; + AssumptionCache &AC; + OrderedInstructions OI; + // This maps from copy operands to Predicate Info. Note that it does not own + // the Predicate Info, they belong to the ValueInfo structs in the ValueInfos + // vector. + DenseMap<const Value *, const PredicateBase *> PredicateMap; + // This stores info about each operand or comparison result we make copies + // of. The real ValueInfos start at index 1, index 0 is unused so that we can + // more easily detect invalid indexing. + SmallVector<ValueInfo, 32> ValueInfos; + // This gives the index into the ValueInfos array for a given Value. Because + // 0 is not a valid Value Info index, you can use DenseMap::lookup and tell + // whether it returned a valid result. + DenseMap<Value *, unsigned int> ValueInfoNums; + // The set of edges along which we can only handle phi uses, due to critical + // edges. + DenseSet<std::pair<BasicBlock *, BasicBlock *>> EdgeUsesOnly; + // The set of ssa_copy declarations we created with our custom mangling. + SmallSet<AssertingVH<Function>, 20> CreatedDeclarations; +}; + +// This pass does eager building and then printing of PredicateInfo. It is used +// by +// the tests to be able to build, dump, and verify PredicateInfo. +class PredicateInfoPrinterLegacyPass : public FunctionPass { +public: + PredicateInfoPrinterLegacyPass(); + + static char ID; + bool runOnFunction(Function &) override; + void getAnalysisUsage(AnalysisUsage &AU) const override; +}; + +/// Printer pass for \c PredicateInfo. +class PredicateInfoPrinterPass + : public PassInfoMixin<PredicateInfoPrinterPass> { + raw_ostream &OS; + +public: + explicit PredicateInfoPrinterPass(raw_ostream &OS) : OS(OS) {} + PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); +}; + +/// Verifier pass for \c PredicateInfo. +struct PredicateInfoVerifierPass : PassInfoMixin<PredicateInfoVerifierPass> { + PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); +}; + +} // end namespace llvm + +#endif // LLVM_TRANSFORMS_UTILS_PREDICATEINFO_H |
