Analysis.h

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//===- CodeGen/Analysis.h - CodeGen LLVM IR Analysis Utilities --*- 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 declares several CodeGen-specific LLVM IR analysis utilities.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CODEGEN_ANALYSIS_H
#define LLVM_CODEGEN_ANALYSIS_H
 
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/IR/Instructions.h"
 
namespace llvm {
template <typename T> class SmallVectorImpl;
class Constant;
class GlobalValue;
class LLT;
class MachineBasicBlock;
class MachineFunction;
class TargetLoweringBase;
class TargetLowering;
class TargetMachine;
struct EVT;
 
/// Compute the linearized index of a member in a nested
/// aggregate/struct/array.
///
/// Given an LLVM IR aggregate type and a sequence of insertvalue or
/// extractvalue indices that identify a member, return the linearized index of
/// the start of the member, i.e the number of element in memory before the
/// sought one. This is disconnected from the number of bytes.
///
/// \param Ty is the type indexed by \p Indices.
/// \param Indices is an optional pointer in the indices list to the current
/// index.
/// \param IndicesEnd is the end of the indices list.
/// \param CurIndex is the current index in the recursion.
///
/// \returns \p CurIndex plus the linear index in \p Ty  the indices list.
LLVM_ABI unsigned ComputeLinearIndex(Type *Ty, const unsigned *Indices,
                                     const unsigned *IndicesEnd,
                                     unsigned CurIndex = 0);
 
inline unsigned ComputeLinearIndex(Type *Ty,
                                   ArrayRef<unsigned> Indices,
                                   unsigned CurIndex = 0) {
  return ComputeLinearIndex(Ty, Indices.begin(), Indices.end(), CurIndex);
}
 
/// Given an LLVM IR type, compute non-aggregate subtypes. Optionally also
/// compute their offsets.
LLVM_ABI void ComputeValueTypes(const DataLayout &DL, Type *Ty,
                                SmallVectorImpl<Type *> &Types,
                                SmallVectorImpl<TypeSize> *Offsets = nullptr,
                                TypeSize StartingOffset = TypeSize::getZero());
 
/// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
/// EVTs that represent all the individual underlying
/// non-aggregate types that comprise it.
///
/// If Offsets is non-null, it points to a vector to be filled in
/// with the in-memory offsets of each of the individual values.
///
LLVM_ABI void ComputeValueVTs(const TargetLowering &TLI, const DataLayout &DL,
                              Type *Ty, SmallVectorImpl<EVT> &ValueVTs,
                              SmallVectorImpl<EVT> *MemVTs = nullptr,
                              SmallVectorImpl<TypeSize> *Offsets = nullptr,
                              TypeSize StartingOffset = TypeSize::getZero());
LLVM_ABI void ComputeValueVTs(const TargetLowering &TLI, const DataLayout &DL,
                              Type *Ty, SmallVectorImpl<EVT> &ValueVTs,
                              SmallVectorImpl<EVT> *MemVTs,
                              SmallVectorImpl<uint64_t> *FixedOffsets,
                              uint64_t StartingOffset);
 
/// computeValueLLTs - Given an LLVM IR type, compute a sequence of
/// LLTs that represent all the individual underlying
/// non-aggregate types that comprise it.
///
/// If Offsets is non-null, it points to a vector to be filled in
/// with the in-memory offsets of each of the individual values.
///
LLVM_ABI void computeValueLLTs(const DataLayout &DL, Type &Ty,
                               SmallVectorImpl<LLT> &ValueLLTs,
                               SmallVectorImpl<TypeSize> *Offsets = nullptr,
                               TypeSize StartingOffset = TypeSize::getZero());
LLVM_ABI void computeValueLLTs(const DataLayout &DL, Type &Ty,
                               SmallVectorImpl<LLT> &ValueLLTs,
                               SmallVectorImpl<uint64_t> *FixedOffsets,
                               uint64_t FixedStartingOffset = 0);
 
/// ExtractTypeInfo - Returns the type info, possibly bitcast, encoded in V.
LLVM_ABI GlobalValue *ExtractTypeInfo(Value *V);
 
/// Return true if landingpad result type \p Ty is a struct of an exception
/// pointer (pointer or integer) and an integer selector, the only lowerable
/// form.
LLVM_ABI bool isExceptionPointerAndSelectorType(Type *Ty);
 
/// getFCmpCondCode - Return the ISD condition code corresponding to
/// the given LLVM IR floating-point condition code.  This includes
/// consideration of global floating-point math flags.
///
LLVM_ABI ISD::CondCode getFCmpCondCode(FCmpInst::Predicate Pred);
 
/// getFCmpCodeWithoutNaN - Given an ISD condition code comparing floats,
/// return the equivalent code if we're allowed to assume that NaNs won't occur.
LLVM_ABI ISD::CondCode getFCmpCodeWithoutNaN(ISD::CondCode CC);
 
/// getICmpCondCode - Return the ISD condition code corresponding to
/// the given LLVM IR integer condition code.
LLVM_ABI ISD::CondCode getICmpCondCode(ICmpInst::Predicate Pred);
 
/// getICmpCondCode - Return the LLVM IR integer condition code
/// corresponding to the given ISD integer condition code.
LLVM_ABI ICmpInst::Predicate getICmpCondCode(ISD::CondCode Pred);
 
/// Test if the address of \p GV can be described in debug info as a plain
/// reference to its symbol, so that a variable holding that address can be
/// described for the whole of its scope rather than only from wherever the
/// address happens to be materialized.
///
/// Whether the symbol alone denotes the runtime address depends on \p MF: the
/// relocation model decides whether a base has to be added to it, and the
/// debug format and DWARF version decide whether the result can be spelled as
/// a value rather than as a place to load from.
LLVM_ABI bool canDescribeGlobalAddressInDebugInfo(const GlobalValue *GV,
                                                  const MachineFunction &MF);
 
/// If \p C is the address of a global, possibly displaced by a constant,
/// return that global and set \p Offset to the displacement in bytes. Returns
/// nullptr if \p C is not such an address, or if the global's address cannot be
/// described per canDescribeGlobalAddressInDebugInfo(). \p Offset is set to
/// zero in those cases, so it only carries a displacement alongside a global.
LLVM_ABI const GlobalValue *
getDescribableGlobalAddress(const Constant *C, int64_t &Offset,
                            const MachineFunction &MF);
 
/// Test if the debug info for \p MF can name a describable global address in a
/// location list too, rather than only in a variable's single location. Where
/// it cannot, a register holding the address is the more robust description.
LLVM_ABI bool canDescribeGlobalAddressInLocationList(const MachineFunction &MF);
 
/// Test if the given instruction is in a position to be optimized
/// with a tail-call. This roughly means that it's in a block with
/// a return and there's nothing that needs to be scheduled
/// between it and the return.
///
/// This function only tests target-independent requirements.
LLVM_ABI bool isInTailCallPosition(const CallBase &Call,
                                   const TargetMachine &TM,
                                   bool ReturnsFirstArg = false);
 
/// Test if given that the input instruction is in the tail call position, if
/// there is an attribute mismatch between the caller and the callee that will
/// inhibit tail call optimizations.
/// \p AllowDifferingSizes is an output parameter which, if forming a tail call
/// is permitted, determines whether it's permitted only if the size of the
/// caller's and callee's return types match exactly.
LLVM_ABI bool attributesPermitTailCall(const Function *F, const Instruction *I,
                                       const ReturnInst *Ret,
                                       const TargetLoweringBase &TLI,
                                       bool *AllowDifferingSizes = nullptr);
 
/// Test if given that the input instruction is in the tail call position if the
/// return type or any attributes of the function will inhibit tail call
/// optimization.
LLVM_ABI bool returnTypeIsEligibleForTailCall(const Function *F,
                                              const Instruction *I,
                                              const ReturnInst *Ret,
                                              const TargetLoweringBase &TLI,
                                              bool ReturnsFirstArg = false);
 
/// Returns true if the parent of \p CI returns CI's first argument after
/// calling \p CI.
LLVM_ABI bool funcReturnsFirstArgOfCall(const CallInst &CI);
 
LLVM_ABI DenseMap<const MachineBasicBlock *, int>
getEHScopeMembership(const MachineFunction &MF);
 
} // End llvm namespace
 
#endif