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Diffstat (limited to 'include/llvm/Analysis/TargetTransformInfo.h')
| -rw-r--r-- | include/llvm/Analysis/TargetTransformInfo.h | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/include/llvm/Analysis/TargetTransformInfo.h b/include/llvm/Analysis/TargetTransformInfo.h new file mode 100644 index 0000000..a9d6725 --- /dev/null +++ b/include/llvm/Analysis/TargetTransformInfo.h @@ -0,0 +1,349 @@ +//===- llvm/Analysis/TargetTransformInfo.h ----------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This pass exposes codegen information to IR-level passes. Every +// transformation that uses codegen information is broken into three parts: +// 1. The IR-level analysis pass. +// 2. The IR-level transformation interface which provides the needed +// information. +// 3. Codegen-level implementation which uses target-specific hooks. +// +// This file defines #2, which is the interface that IR-level transformations +// use for querying the codegen. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ANALYSIS_TARGETTRANSFORMINFO_H +#define LLVM_ANALYSIS_TARGETTRANSFORMINFO_H + +#include "llvm/IR/Intrinsics.h" +#include "llvm/Pass.h" +#include "llvm/Support/DataTypes.h" + +namespace llvm { + +class GlobalValue; +class Type; +class User; +class Value; + +/// TargetTransformInfo - This pass provides access to the codegen +/// interfaces that are needed for IR-level transformations. +class TargetTransformInfo { +protected: + /// \brief The TTI instance one level down the stack. + /// + /// This is used to implement the default behavior all of the methods which + /// is to delegate up through the stack of TTIs until one can answer the + /// query. + TargetTransformInfo *PrevTTI; + + /// \brief The top of the stack of TTI analyses available. + /// + /// This is a convenience routine maintained as TTI analyses become available + /// that complements the PrevTTI delegation chain. When one part of an + /// analysis pass wants to query another part of the analysis pass it can use + /// this to start back at the top of the stack. + TargetTransformInfo *TopTTI; + + /// All pass subclasses must in their initializePass routine call + /// pushTTIStack with themselves to update the pointers tracking the previous + /// TTI instance in the analysis group's stack, and the top of the analysis + /// group's stack. + void pushTTIStack(Pass *P); + + /// All pass subclasses must in their finalizePass routine call popTTIStack + /// to update the pointers tracking the previous TTI instance in the analysis + /// group's stack, and the top of the analysis group's stack. + void popTTIStack(); + + /// All pass subclasses must call TargetTransformInfo::getAnalysisUsage. + virtual void getAnalysisUsage(AnalysisUsage &AU) const; + +public: + /// This class is intended to be subclassed by real implementations. + virtual ~TargetTransformInfo() = 0; + + /// \name Generic Target Information + /// @{ + + /// \brief Underlying constants for 'cost' values in this interface. + /// + /// Many APIs in this interface return a cost. This enum defines the + /// fundamental values that should be used to interpret (and produce) those + /// costs. The costs are returned as an unsigned rather than a member of this + /// enumeration because it is expected that the cost of one IR instruction + /// may have a multiplicative factor to it or otherwise won't fit directly + /// into the enum. Moreover, it is common to sum or average costs which works + /// better as simple integral values. Thus this enum only provides constants. + /// + /// Note that these costs should usually reflect the intersection of code-size + /// cost and execution cost. A free instruction is typically one that folds + /// into another instruction. For example, reg-to-reg moves can often be + /// skipped by renaming the registers in the CPU, but they still are encoded + /// and thus wouldn't be considered 'free' here. + enum TargetCostConstants { + TCC_Free = 0, ///< Expected to fold away in lowering. + TCC_Basic = 1, ///< The cost of a typical 'add' instruction. + TCC_Expensive = 4 ///< The cost of a 'div' instruction on x86. + }; + + /// \brief Estimate the cost of a specific operation when lowered. + /// + /// Note that this is designed to work on an arbitrary synthetic opcode, and + /// thus work for hypothetical queries before an instruction has even been + /// formed. However, this does *not* work for GEPs, and must not be called + /// for a GEP instruction. Instead, use the dedicated getGEPCost interface as + /// analyzing a GEP's cost required more information. + /// + /// Typically only the result type is required, and the operand type can be + /// omitted. However, if the opcode is one of the cast instructions, the + /// operand type is required. + /// + /// The returned cost is defined in terms of \c TargetCostConstants, see its + /// comments for a detailed explanation of the cost values. + virtual unsigned getOperationCost(unsigned Opcode, Type *Ty, + Type *OpTy = 0) const; + + /// \brief Estimate the cost of a GEP operation when lowered. + /// + /// The contract for this function is the same as \c getOperationCost except + /// that it supports an interface that provides extra information specific to + /// the GEP operation. + virtual unsigned getGEPCost(const Value *Ptr, + ArrayRef<const Value *> Operands) const; + + /// \brief Estimate the cost of a function call when lowered. + /// + /// The contract for this is the same as \c getOperationCost except that it + /// supports an interface that provides extra information specific to call + /// instructions. + /// + /// This is the most basic query for estimating call cost: it only knows the + /// function type and (potentially) the number of arguments at the call site. + /// The latter is only interesting for varargs function types. + virtual unsigned getCallCost(FunctionType *FTy, int NumArgs = -1) const; + + /// \brief Estimate the cost of calling a specific function when lowered. + /// + /// This overload adds the ability to reason about the particular function + /// being called in the event it is a library call with special lowering. + virtual unsigned getCallCost(const Function *F, int NumArgs = -1) const; + + /// \brief Estimate the cost of calling a specific function when lowered. + /// + /// This overload allows specifying a set of candidate argument values. + virtual unsigned getCallCost(const Function *F, + ArrayRef<const Value *> Arguments) const; + + /// \brief Estimate the cost of an intrinsic when lowered. + /// + /// Mirrors the \c getCallCost method but uses an intrinsic identifier. + virtual unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy, + ArrayRef<Type *> ParamTys) const; + + /// \brief Estimate the cost of an intrinsic when lowered. + /// + /// Mirrors the \c getCallCost method but uses an intrinsic identifier. + virtual unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy, + ArrayRef<const Value *> Arguments) const; + + /// \brief Estimate the cost of a given IR user when lowered. + /// + /// This can estimate the cost of either a ConstantExpr or Instruction when + /// lowered. It has two primary advantages over the \c getOperationCost and + /// \c getGEPCost above, and one significant disadvantage: it can only be + /// used when the IR construct has already been formed. + /// + /// The advantages are that it can inspect the SSA use graph to reason more + /// accurately about the cost. For example, all-constant-GEPs can often be + /// folded into a load or other instruction, but if they are used in some + /// other context they may not be folded. This routine can distinguish such + /// cases. + /// + /// The returned cost is defined in terms of \c TargetCostConstants, see its + /// comments for a detailed explanation of the cost values. + virtual unsigned getUserCost(const User *U) const; + + /// \brief Test whether calls to a function lower to actual program function + /// calls. + /// + /// The idea is to test whether the program is likely to require a 'call' + /// instruction or equivalent in order to call the given function. + /// + /// FIXME: It's not clear that this is a good or useful query API. Client's + /// should probably move to simpler cost metrics using the above. + /// Alternatively, we could split the cost interface into distinct code-size + /// and execution-speed costs. This would allow modelling the core of this + /// query more accurately as the a call is a single small instruction, but + /// incurs significant execution cost. + virtual bool isLoweredToCall(const Function *F) const; + + /// @} + + /// \name Scalar Target Information + /// @{ + + /// \brief Flags indicating the kind of support for population count. + /// + /// Compared to the SW implementation, HW support is supposed to + /// significantly boost the performance when the population is dense, and it + /// may or may not degrade performance if the population is sparse. A HW + /// support is considered as "Fast" if it can outperform, or is on a par + /// with, SW implementation when the population is sparse; otherwise, it is + /// considered as "Slow". + enum PopcntSupportKind { + PSK_Software, + PSK_SlowHardware, + PSK_FastHardware + }; + + /// isLegalAddImmediate - Return true if the specified immediate is legal + /// add immediate, that is the target has add instructions which can add + /// a register with the immediate without having to materialize the + /// immediate into a register. + virtual bool isLegalAddImmediate(int64_t Imm) const; + + /// isLegalICmpImmediate - Return true if the specified immediate is legal + /// icmp immediate, that is the target has icmp instructions which can compare + /// a register against the immediate without having to materialize the + /// immediate into a register. + virtual bool isLegalICmpImmediate(int64_t Imm) const; + + /// isLegalAddressingMode - Return true if the addressing mode represented by + /// AM is legal for this target, for a load/store of the specified type. + /// The type may be VoidTy, in which case only return true if the addressing + /// mode is legal for a load/store of any legal type. + /// TODO: Handle pre/postinc as well. + virtual bool isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV, + int64_t BaseOffset, bool HasBaseReg, + int64_t Scale) const; + + /// isTruncateFree - Return true if it's free to truncate a value of + /// type Ty1 to type Ty2. e.g. On x86 it's free to truncate a i32 value in + /// register EAX to i16 by referencing its sub-register AX. + virtual bool isTruncateFree(Type *Ty1, Type *Ty2) const; + + /// Is this type legal. + virtual bool isTypeLegal(Type *Ty) const; + + /// getJumpBufAlignment - returns the target's jmp_buf alignment in bytes + virtual unsigned getJumpBufAlignment() const; + + /// getJumpBufSize - returns the target's jmp_buf size in bytes. + virtual unsigned getJumpBufSize() const; + + /// shouldBuildLookupTables - Return true if switches should be turned into + /// lookup tables for the target. + virtual bool shouldBuildLookupTables() const; + + /// getPopcntSupport - Return hardware support for population count. + virtual PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) const; + + /// getIntImmCost - Return the expected cost of materializing the given + /// integer immediate of the specified type. + virtual unsigned getIntImmCost(const APInt &Imm, Type *Ty) const; + + /// @} + + /// \name Vector Target Information + /// @{ + + /// \brief The various kinds of shuffle patterns for vector queries. + enum ShuffleKind { + SK_Broadcast, ///< Broadcast element 0 to all other elements. + SK_Reverse, ///< Reverse the order of the vector. + SK_InsertSubvector, ///< InsertSubvector. Index indicates start offset. + SK_ExtractSubvector ///< ExtractSubvector Index indicates start offset. + }; + + /// \brief Additonal information about an operand's possible values. + enum OperandValueKind { + OK_AnyValue, // Operand can have any value. + OK_UniformValue, // Operand is uniform (splat of a value). + OK_UniformConstantValue // Operand is uniform constant. + }; + + /// \return The number of scalar or vector registers that the target has. + /// If 'Vectors' is true, it returns the number of vector registers. If it is + /// set to false, it returns the number of scalar registers. + virtual unsigned getNumberOfRegisters(bool Vector) const; + + /// \return The width of the largest scalar or vector register type. + virtual unsigned getRegisterBitWidth(bool Vector) const; + + /// \return The maximum unroll factor that the vectorizer should try to + /// perform for this target. This number depends on the level of parallelism + /// and the number of execution units in the CPU. + virtual unsigned getMaximumUnrollFactor() const; + + /// \return The expected cost of arithmetic ops, such as mul, xor, fsub, etc. + virtual unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty, + OperandValueKind Opd1Info = OK_AnyValue, + OperandValueKind Opd2Info = OK_AnyValue) const; + + /// \return The cost of a shuffle instruction of kind Kind and of type Tp. + /// The index and subtype parameters are used by the subvector insertion and + /// extraction shuffle kinds. + virtual unsigned getShuffleCost(ShuffleKind Kind, Type *Tp, int Index = 0, + Type *SubTp = 0) const; + + /// \return The expected cost of cast instructions, such as bitcast, trunc, + /// zext, etc. + virtual unsigned getCastInstrCost(unsigned Opcode, Type *Dst, + Type *Src) const; + + /// \return The expected cost of control-flow related instructions such as + /// Phi, Ret, Br. + virtual unsigned getCFInstrCost(unsigned Opcode) const; + + /// \returns The expected cost of compare and select instructions. + virtual unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy, + Type *CondTy = 0) const; + + /// \return The expected cost of vector Insert and Extract. + /// Use -1 to indicate that there is no information on the index value. + virtual unsigned getVectorInstrCost(unsigned Opcode, Type *Val, + unsigned Index = -1) const; + + /// \return The cost of Load and Store instructions. + virtual unsigned getMemoryOpCost(unsigned Opcode, Type *Src, + unsigned Alignment, + unsigned AddressSpace) const; + + /// \returns The cost of Intrinsic instructions. + virtual unsigned getIntrinsicInstrCost(Intrinsic::ID ID, Type *RetTy, + ArrayRef<Type *> Tys) const; + + /// \returns The number of pieces into which the provided type must be + /// split during legalization. Zero is returned when the answer is unknown. + virtual unsigned getNumberOfParts(Type *Tp) const; + + /// \returns The cost of the address computation. For most targets this can be + /// merged into the instruction indexing mode. Some targets might want to + /// distinguish between address computation for memory operations on vector + /// types and scalar types. Such targets should override this function. + virtual unsigned getAddressComputationCost(Type *Ty) const; + + /// @} + + /// Analysis group identification. + static char ID; +}; + +/// \brief Create the base case instance of a pass in the TTI analysis group. +/// +/// This class provides the base case for the stack of TTI analyzes. It doesn't +/// delegate to anything and uses the STTI and VTTI objects passed in to +/// satisfy the queries. +ImmutablePass *createNoTargetTransformInfoPass(); + +} // End llvm namespace + +#endif |
