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//===- llvm/CodeGen/MachineBasicBlock.h -------------------------*- 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
//
//===----------------------------------------------------------------------===//
//
// Collect the sequence of machine instructions for a basic block.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H
#define LLVM_CODEGEN_MACHINEBASICBLOCK_H
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/SparseBitVector.h"
#include "llvm/ADT/ilist.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBundleIterator.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/MC/LaneBitmask.h"
#include "llvm/Support/BranchProbability.h"
#include <cassert>
#include <cstdint>
#include <iterator>
#include <string>
#include <vector>
namespace llvm {
class BasicBlock;
class MachineFunction;
class MCSymbol;
class ModuleSlotTracker;
class Pass;
class Printable;
class SlotIndexes;
class StringRef;
class raw_ostream;
class LiveIntervals;
class TargetRegisterClass;
class TargetRegisterInfo;
template <typename IRUnitT, typename... ExtraArgTs> class AnalysisManager;
using MachineFunctionAnalysisManager = AnalysisManager<MachineFunction>;
// This structure uniquely identifies a basic block section.
// Possible values are
// {Type: Default, Number: (unsigned)} (These are regular section IDs)
// {Type: Exception, Number: 0} (ExceptionSectionID)
// {Type: Cold, Number: 0} (ColdSectionID)
struct MBBSectionID {
enum SectionType {
Default = 0, // Regular section (these sections are distinguished by the
// Number field).
Exception, // Special section type for exception handling blocks
Cold, // Special section type for cold blocks
} Type;
unsigned Number;
MBBSectionID(unsigned N) : Type(Default), Number(N) {}
// Special unique sections for cold and exception blocks.
const static MBBSectionID ColdSectionID;
const static MBBSectionID ExceptionSectionID;
bool operator==(const MBBSectionID &Other) const {
return Type == Other.Type && Number == Other.Number;
}
bool operator!=(const MBBSectionID &Other) const { return !(*this == Other); }
private:
// This is only used to construct the special cold and exception sections.
MBBSectionID(SectionType T) : Type(T), Number(0) {}
};
template <> struct DenseMapInfo<MBBSectionID> {
using TypeInfo = DenseMapInfo<MBBSectionID::SectionType>;
using NumberInfo = DenseMapInfo<unsigned>;
static inline MBBSectionID getEmptyKey() {
return MBBSectionID(NumberInfo::getEmptyKey());
}
static inline MBBSectionID getTombstoneKey() {
return MBBSectionID(NumberInfo::getTombstoneKey());
}
static unsigned getHashValue(const MBBSectionID &SecID) {
return detail::combineHashValue(TypeInfo::getHashValue(SecID.Type),
NumberInfo::getHashValue(SecID.Number));
}
static bool isEqual(const MBBSectionID &LHS, const MBBSectionID &RHS) {
return LHS == RHS;
}
};
// This structure represents the information for a basic block pertaining to
// the basic block sections profile.
struct UniqueBBID {
unsigned BaseID;
unsigned CloneID;
};
template <> struct ilist_traits<MachineInstr> {
private:
friend class MachineBasicBlock; // Set by the owning MachineBasicBlock.
MachineBasicBlock *Parent;
using instr_iterator =
simple_ilist<MachineInstr, ilist_sentinel_tracking<true>>::iterator;
public:
void addNodeToList(MachineInstr *N);
void removeNodeFromList(MachineInstr *N);
void transferNodesFromList(ilist_traits &FromList, instr_iterator First,
instr_iterator Last);
void deleteNode(MachineInstr *MI);
};
class MachineBasicBlock
: public ilist_node_with_parent<MachineBasicBlock, MachineFunction> {
public:
/// Pair of physical register and lane mask.
/// This is not simply a std::pair typedef because the members should be named
/// clearly as they both have an integer type.
struct RegisterMaskPair {
public:
MCPhysReg PhysReg;
LaneBitmask LaneMask;
RegisterMaskPair(MCPhysReg PhysReg, LaneBitmask LaneMask)
: PhysReg(PhysReg), LaneMask(LaneMask) {}
bool operator==(const RegisterMaskPair &other) const {
return PhysReg == other.PhysReg && LaneMask == other.LaneMask;
}
};
private:
using Instructions = ilist<MachineInstr, ilist_sentinel_tracking<true>>;
const BasicBlock *BB;
int Number;
/// The call frame size on entry to this basic block due to call frame setup
/// instructions in a predecessor. This is usually zero, unless basic blocks
/// are split in the middle of a call sequence.
///
/// This information is only maintained until PrologEpilogInserter eliminates
/// call frame pseudos.
unsigned CallFrameSize = 0;
MachineFunction *xParent;
Instructions Insts;
/// Keep track of the predecessor / successor basic blocks.
std::vector<MachineBasicBlock *> Predecessors;
std::vector<MachineBasicBlock *> Successors;
/// Keep track of the probabilities to the successors. This vector has the
/// same order as Successors, or it is empty if we don't use it (disable
/// optimization).
std::vector<BranchProbability> Probs;
using probability_iterator = std::vector<BranchProbability>::iterator;
using const_probability_iterator =
std::vector<BranchProbability>::const_iterator;
std::optional<uint64_t> IrrLoopHeaderWeight;
/// Keep track of the physical registers that are livein of the basicblock.
using LiveInVector = std::vector<RegisterMaskPair>;
LiveInVector LiveIns;
/// Alignment of the basic block. One if the basic block does not need to be
/// aligned.
Align Alignment;
/// Maximum amount of bytes that can be added to align the basic block. If the
/// alignment cannot be reached in this many bytes, no bytes are emitted.
/// Zero to represent no maximum.
unsigned MaxBytesForAlignment = 0;
/// Indicate that this basic block is entered via an exception handler.
bool IsEHPad = false;
/// Indicate that this MachineBasicBlock is referenced somewhere other than
/// as predecessor/successor, a terminator MachineInstr, or a jump table.
bool MachineBlockAddressTaken = false;
/// If this MachineBasicBlock corresponds to an IR-level "blockaddress"
/// constant, this contains a pointer to that block.
BasicBlock *AddressTakenIRBlock = nullptr;
/// Indicate that this basic block needs its symbol be emitted regardless of
/// whether the flow just falls-through to it.
bool LabelMustBeEmitted = false;
/// Indicate that this basic block is the entry block of an EH scope, i.e.,
/// the block that used to have a catchpad or cleanuppad instruction in the
/// LLVM IR.
bool IsEHScopeEntry = false;
/// Indicates if this is a target block of a catchret.
bool IsEHCatchretTarget = false;
/// Indicate that this basic block is the entry block of an EH funclet.
bool IsEHFuncletEntry = false;
/// Indicate that this basic block is the entry block of a cleanup funclet.
bool IsCleanupFuncletEntry = false;
/// Fixed unique ID assigned to this basic block upon creation. Used with
/// basic block sections and basic block labels.
std::optional<UniqueBBID> BBID;
/// With basic block sections, this stores the Section ID of the basic block.
MBBSectionID SectionID{0};
// Indicate that this basic block begins a section.
bool IsBeginSection = false;
// Indicate that this basic block ends a section.
bool IsEndSection = false;
/// Indicate that this basic block is the indirect dest of an INLINEASM_BR.
bool IsInlineAsmBrIndirectTarget = false;
/// since getSymbol is a relatively heavy-weight operation, the symbol
/// is only computed once and is cached.
mutable MCSymbol *CachedMCSymbol = nullptr;
/// Cached MCSymbol for this block (used if IsEHCatchRetTarget).
mutable MCSymbol *CachedEHCatchretMCSymbol = nullptr;
/// Marks the end of the basic block. Used during basic block sections to
/// calculate the size of the basic block, or the BB section ending with it.
mutable MCSymbol *CachedEndMCSymbol = nullptr;
// Intrusive list support
MachineBasicBlock() = default;
explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB);
~MachineBasicBlock();
// MachineBasicBlocks are allocated and owned by MachineFunction.
friend class MachineFunction;
public:
/// Return the LLVM basic block that this instance corresponded to originally.
/// Note that this may be NULL if this instance does not correspond directly
/// to an LLVM basic block.
const BasicBlock *getBasicBlock() const { return BB; }
/// Remove the reference to the underlying IR BasicBlock. This is for
/// reduction tools and should generally not be used.
void clearBasicBlock() {
BB = nullptr;
}
/// Check if there is a name of corresponding LLVM basic block.
bool hasName() const;
/// Return the name of the corresponding LLVM basic block, or an empty string.
StringRef getName() const;
/// Return a formatted string to identify this block and its parent function.
std::string getFullName() const;
/// Test whether this block is used as something other than the target
/// of a terminator, exception-handling target, or jump table. This is
/// either the result of an IR-level "blockaddress", or some form
/// of target-specific branch lowering.
bool hasAddressTaken() const {
return MachineBlockAddressTaken || AddressTakenIRBlock;
}
/// Test whether this block is used as something other than the target of a
/// terminator, exception-handling target, jump table, or IR blockaddress.
/// For example, its address might be loaded into a register, or
/// stored in some branch table that isn't part of MachineJumpTableInfo.
bool isMachineBlockAddressTaken() const { return MachineBlockAddressTaken; }
/// Test whether this block is the target of an IR BlockAddress. (There can
/// more than one MBB associated with an IR BB where the address is taken.)
bool isIRBlockAddressTaken() const { return AddressTakenIRBlock; }
/// Retrieves the BasicBlock which corresponds to this MachineBasicBlock.
BasicBlock *getAddressTakenIRBlock() const { return AddressTakenIRBlock; }
/// Set this block to indicate that its address is used as something other
/// than the target of a terminator, exception-handling target, jump table,
/// or IR-level "blockaddress".
void setMachineBlockAddressTaken() { MachineBlockAddressTaken = true; }
/// Set this block to reflect that it corresponds to an IR-level basic block
/// with a BlockAddress.
void setAddressTakenIRBlock(BasicBlock *BB) { AddressTakenIRBlock = BB; }
/// Test whether this block must have its label emitted.
bool hasLabelMustBeEmitted() const { return LabelMustBeEmitted; }
/// Set this block to reflect that, regardless how we flow to it, we need
/// its label be emitted.
void setLabelMustBeEmitted() { LabelMustBeEmitted = true; }
/// Return the MachineFunction containing this basic block.
const MachineFunction *getParent() const { return xParent; }
MachineFunction *getParent() { return xParent; }
using instr_iterator = Instructions::iterator;
using const_instr_iterator = Instructions::const_iterator;
using reverse_instr_iterator = Instructions::reverse_iterator;
using const_reverse_instr_iterator = Instructions::const_reverse_iterator;
using iterator = MachineInstrBundleIterator<MachineInstr>;
using const_iterator = MachineInstrBundleIterator<const MachineInstr>;
using reverse_iterator = MachineInstrBundleIterator<MachineInstr, true>;
using const_reverse_iterator =
MachineInstrBundleIterator<const MachineInstr, true>;
unsigned size() const { return (unsigned)Insts.size(); }
bool sizeWithoutDebugLargerThan(unsigned Limit) const;
bool empty() const { return Insts.empty(); }
MachineInstr &instr_front() { return Insts.front(); }
MachineInstr &instr_back() { return Insts.back(); }
const MachineInstr &instr_front() const { return Insts.front(); }
const MachineInstr &instr_back() const { return Insts.back(); }
MachineInstr &front() { return Insts.front(); }
MachineInstr &back() { return *--end(); }
const MachineInstr &front() const { return Insts.front(); }
const MachineInstr &back() const { return *--end(); }
instr_iterator instr_begin() { return Insts.begin(); }
const_instr_iterator instr_begin() const { return Insts.begin(); }
instr_iterator instr_end() { return Insts.end(); }
const_instr_iterator instr_end() const { return Insts.end(); }
reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); }
const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); }
reverse_instr_iterator instr_rend () { return Insts.rend(); }
const_reverse_instr_iterator instr_rend () const { return Insts.rend(); }
using instr_range = iterator_range<instr_iterator>;
using const_instr_range = iterator_range<const_instr_iterator>;
instr_range instrs() { return instr_range(instr_begin(), instr_end()); }
const_instr_range instrs() const {
return const_instr_range(instr_begin(), instr_end());
}
iterator begin() { return instr_begin(); }
const_iterator begin() const { return instr_begin(); }
iterator end () { return instr_end(); }
const_iterator end () const { return instr_end(); }
reverse_iterator rbegin() {
return reverse_iterator::getAtBundleBegin(instr_rbegin());
}
const_reverse_iterator rbegin() const {
return const_reverse_iterator::getAtBundleBegin(instr_rbegin());
}
reverse_iterator rend() { return reverse_iterator(instr_rend()); }
const_reverse_iterator rend() const {
return const_reverse_iterator(instr_rend());
}
/// Support for MachineInstr::getNextNode().
static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) {
return &MachineBasicBlock::Insts;
}
inline iterator_range<iterator> terminators() {
return make_range(getFirstTerminator(), end());
}
inline iterator_range<const_iterator> terminators() const {
return make_range(getFirstTerminator(), end());
}
/// Returns a range that iterates over the phis in the basic block.
inline iterator_range<iterator> phis() {
return make_range(begin(), getFirstNonPHI());
}
inline iterator_range<const_iterator> phis() const {
return const_cast<MachineBasicBlock *>(this)->phis();
}
// Machine-CFG iterators
using pred_iterator = std::vector<MachineBasicBlock *>::iterator;
using const_pred_iterator = std::vector<MachineBasicBlock *>::const_iterator;
using succ_iterator = std::vector<MachineBasicBlock *>::iterator;
using const_succ_iterator = std::vector<MachineBasicBlock *>::const_iterator;
using pred_reverse_iterator =
std::vector<MachineBasicBlock *>::reverse_iterator;
using const_pred_reverse_iterator =
std::vector<MachineBasicBlock *>::const_reverse_iterator;
using succ_reverse_iterator =
std::vector<MachineBasicBlock *>::reverse_iterator;
using const_succ_reverse_iterator =
std::vector<MachineBasicBlock *>::const_reverse_iterator;
pred_iterator pred_begin() { return Predecessors.begin(); }
const_pred_iterator pred_begin() const { return Predecessors.begin(); }
pred_iterator pred_end() { return Predecessors.end(); }
const_pred_iterator pred_end() const { return Predecessors.end(); }
pred_reverse_iterator pred_rbegin()
{ return Predecessors.rbegin();}
const_pred_reverse_iterator pred_rbegin() const
{ return Predecessors.rbegin();}
pred_reverse_iterator pred_rend()
{ return Predecessors.rend(); }
const_pred_reverse_iterator pred_rend() const
{ return Predecessors.rend(); }
unsigned pred_size() const {
return (unsigned)Predecessors.size();
}
bool pred_empty() const { return Predecessors.empty(); }
succ_iterator succ_begin() { return Successors.begin(); }
const_succ_iterator succ_begin() const { return Successors.begin(); }
succ_iterator succ_end() { return Successors.end(); }
const_succ_iterator succ_end() const { return Successors.end(); }
succ_reverse_iterator succ_rbegin()
{ return Successors.rbegin(); }
const_succ_reverse_iterator succ_rbegin() const
{ return Successors.rbegin(); }
succ_reverse_iterator succ_rend()
{ return Successors.rend(); }
const_succ_reverse_iterator succ_rend() const
{ return Successors.rend(); }
unsigned succ_size() const {
return (unsigned)Successors.size();
}
bool succ_empty() const { return Successors.empty(); }
inline iterator_range<pred_iterator> predecessors() {
return make_range(pred_begin(), pred_end());
}
inline iterator_range<const_pred_iterator> predecessors() const {
return make_range(pred_begin(), pred_end());
}
inline iterator_range<succ_iterator> successors() {
return make_range(succ_begin(), succ_end());
}
inline iterator_range<const_succ_iterator> successors() const {
return make_range(succ_begin(), succ_end());
}
// LiveIn management methods.
/// Adds the specified register as a live in. Note that it is an error to add
/// the same register to the same set more than once unless the intention is
/// to call sortUniqueLiveIns after all registers are added.
void addLiveIn(MCRegister PhysReg,
LaneBitmask LaneMask = LaneBitmask::getAll()) {
LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask));
}
void addLiveIn(const RegisterMaskPair &RegMaskPair) {
LiveIns.push_back(RegMaskPair);
}
/// Sorts and uniques the LiveIns vector. It can be significantly faster to do
/// this than repeatedly calling isLiveIn before calling addLiveIn for every
/// LiveIn insertion.
void sortUniqueLiveIns();
/// Clear live in list.
void clearLiveIns();
/// Clear the live in list, and return the removed live in's in \p OldLiveIns.
/// Requires that the vector \p OldLiveIns is empty.
void clearLiveIns(std::vector<RegisterMaskPair> &OldLiveIns);
/// Add PhysReg as live in to this block, and ensure that there is a copy of
/// PhysReg to a virtual register of class RC. Return the virtual register
/// that is a copy of the live in PhysReg.
Register addLiveIn(MCRegister PhysReg, const TargetRegisterClass *RC);
/// Remove the specified register from the live in set.
void removeLiveIn(MCPhysReg Reg,
LaneBitmask LaneMask = LaneBitmask::getAll());
/// Return true if the specified register is in the live in set.
bool isLiveIn(MCPhysReg Reg,
LaneBitmask LaneMask = LaneBitmask::getAll()) const;
// Iteration support for live in sets. These sets are kept in sorted
// order by their register number.
using livein_iterator = LiveInVector::const_iterator;
/// Unlike livein_begin, this method does not check that the liveness
/// information is accurate. Still for debug purposes it may be useful
/// to have iterators that won't assert if the liveness information
/// is not current.
livein_iterator livein_begin_dbg() const { return LiveIns.begin(); }
iterator_range<livein_iterator> liveins_dbg() const {
return make_range(livein_begin_dbg(), livein_end());
}
livein_iterator livein_begin() const;
livein_iterator livein_end() const { return LiveIns.end(); }
bool livein_empty() const { return LiveIns.empty(); }
iterator_range<livein_iterator> liveins() const {
return make_range(livein_begin(), livein_end());
}
/// Remove entry from the livein set and return iterator to the next.
livein_iterator removeLiveIn(livein_iterator I);
const std::vector<RegisterMaskPair> &getLiveIns() const { return LiveIns; }
class liveout_iterator {
public:
using iterator_category = std::input_iterator_tag;
using difference_type = std::ptrdiff_t;
using value_type = RegisterMaskPair;
using pointer = const RegisterMaskPair *;
using reference = const RegisterMaskPair &;
liveout_iterator(const MachineBasicBlock &MBB, MCPhysReg ExceptionPointer,
MCPhysReg ExceptionSelector, bool End)
: ExceptionPointer(ExceptionPointer),
ExceptionSelector(ExceptionSelector), BlockI(MBB.succ_begin()),
BlockEnd(MBB.succ_end()) {
if (End)
BlockI = BlockEnd;
else if (BlockI != BlockEnd) {
LiveRegI = (*BlockI)->livein_begin();
if (!advanceToValidPosition())
return;
if (LiveRegI->PhysReg == ExceptionPointer ||
LiveRegI->PhysReg == ExceptionSelector)
++(*this);
}
}
liveout_iterator &operator++() {
do {
++LiveRegI;
if (!advanceToValidPosition())
return *this;
} while ((*BlockI)->isEHPad() &&
(LiveRegI->PhysReg == ExceptionPointer ||
LiveRegI->PhysReg == ExceptionSelector));
return *this;
}
liveout_iterator operator++(int) {
liveout_iterator Tmp = *this;
++(*this);
return Tmp;
}
reference operator*() const {
return *LiveRegI;
}
pointer operator->() const {
return &*LiveRegI;
}
bool operator==(const liveout_iterator &RHS) const {
if (BlockI != BlockEnd)
return BlockI == RHS.BlockI && LiveRegI == RHS.LiveRegI;
return RHS.BlockI == BlockEnd;
}
bool operator!=(const liveout_iterator &RHS) const {
return !(*this == RHS);
}
private:
bool advanceToValidPosition() {
if (LiveRegI != (*BlockI)->livein_end())
return true;
do {
++BlockI;
} while (BlockI != BlockEnd && (*BlockI)->livein_empty());
if (BlockI == BlockEnd)
return false;
LiveRegI = (*BlockI)->livein_begin();
return true;
}
MCPhysReg ExceptionPointer, ExceptionSelector;
const_succ_iterator BlockI;
const_succ_iterator BlockEnd;
livein_iterator LiveRegI;
};
/// Iterator scanning successor basic blocks' liveins to determine the
/// registers potentially live at the end of this block. There may be
/// duplicates or overlapping registers in the list returned.
liveout_iterator liveout_begin() const;
liveout_iterator liveout_end() const {
return liveout_iterator(*this, 0, 0, true);
}
iterator_range<liveout_iterator> liveouts() const {
return make_range(liveout_begin(), liveout_end());
}
/// Get the clobber mask for the start of this basic block. Funclets use this
/// to prevent register allocation across funclet transitions.
const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const;
/// Get the clobber mask for the end of the basic block.
/// \see getBeginClobberMask()
const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const;
/// Return alignment of the basic block.
Align getAlignment() const { return Alignment; }
/// Set alignment of the basic block.
void setAlignment(Align A) { Alignment = A; }
void setAlignment(Align A, unsigned MaxBytes) {
setAlignment(A);
setMaxBytesForAlignment(MaxBytes);
}
/// Return the maximum amount of padding allowed for aligning the basic block.
unsigned getMaxBytesForAlignment() const { return MaxBytesForAlignment; }
/// Set the maximum amount of padding allowed for aligning the basic block
void setMaxBytesForAlignment(unsigned MaxBytes) {
MaxBytesForAlignment = MaxBytes;
}
/// Returns true if the block is a landing pad. That is this basic block is
/// entered via an exception handler.
bool isEHPad() const { return IsEHPad; }
/// Indicates the block is a landing pad. That is this basic block is entered
/// via an exception handler.
void setIsEHPad(bool V = true) { IsEHPad = V; }
bool hasEHPadSuccessor() const;
/// Returns true if this is the entry block of the function.
bool isEntryBlock() const;
/// Returns true if this is the entry block of an EH scope, i.e., the block
/// that used to have a catchpad or cleanuppad instruction in the LLVM IR.
bool isEHScopeEntry() const { return IsEHScopeEntry; }
/// Indicates if this is the entry block of an EH scope, i.e., the block that
/// that used to have a catchpad or cleanuppad instruction in the LLVM IR.
void setIsEHScopeEntry(bool V = true) { IsEHScopeEntry = V; }
/// Returns true if this is a target block of a catchret.
bool isEHCatchretTarget() const { return IsEHCatchretTarget; }
/// Indicates if this is a target block of a catchret.
void setIsEHCatchretTarget(bool V = true) { IsEHCatchretTarget = V; }
/// Returns true if this is the entry block of an EH funclet.
bool isEHFuncletEntry() const { return IsEHFuncletEntry; }
/// Indicates if this is the entry block of an EH funclet.
void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; }
/// Returns true if this is the entry block of a cleanup funclet.
bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; }
/// Indicates if this is the entry block of a cleanup funclet.
void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; }
/// Returns true if this block begins any section.
bool isBeginSection() const { return IsBeginSection; }
/// Returns true if this block ends any section.
bool isEndSection() const { return IsEndSection; }
void setIsBeginSection(bool V = true) { IsBeginSection = V; }
void setIsEndSection(bool V = true) { IsEndSection = V; }
std::optional<UniqueBBID> getBBID() const { return BBID; }
/// Returns the section ID of this basic block.
MBBSectionID getSectionID() const { return SectionID; }
/// Sets the fixed BBID of this basic block.
void setBBID(const UniqueBBID &V) {
assert(!BBID.has_value() && "Cannot change BBID.");
BBID = V;
}
/// Sets the section ID for this basic block.
void setSectionID(MBBSectionID V) { SectionID = V; }
/// Returns the MCSymbol marking the end of this basic block.
MCSymbol *getEndSymbol() const;
/// Returns true if this block may have an INLINEASM_BR (overestimate, by
/// checking if any of the successors are indirect targets of any inlineasm_br
/// in the function).
bool mayHaveInlineAsmBr() const;
/// Returns true if this is the indirect dest of an INLINEASM_BR.
bool isInlineAsmBrIndirectTarget() const {
return IsInlineAsmBrIndirectTarget;
}
/// Indicates if this is the indirect dest of an INLINEASM_BR.
void setIsInlineAsmBrIndirectTarget(bool V = true) {
IsInlineAsmBrIndirectTarget = V;
}
/// Returns true if it is legal to hoist instructions into this block.
bool isLegalToHoistInto() const;
// Code Layout methods.
/// Move 'this' block before or after the specified block. This only moves
/// the block, it does not modify the CFG or adjust potential fall-throughs at
/// the end of the block.
void moveBefore(MachineBasicBlock *NewAfter);
void moveAfter(MachineBasicBlock *NewBefore);
/// Returns true if this and MBB belong to the same section.
bool sameSection(const MachineBasicBlock *MBB) const {
return getSectionID() == MBB->getSectionID();
}
/// Update the terminator instructions in block to account for changes to
/// block layout which may have been made. PreviousLayoutSuccessor should be
/// set to the block which may have been used as fallthrough before the block
/// layout was modified. If the block previously fell through to that block,
/// it may now need a branch. If it previously branched to another block, it
/// may now be able to fallthrough to the current layout successor.
void updateTerminator(MachineBasicBlock *PreviousLayoutSuccessor);
// Machine-CFG mutators
/// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
/// of Succ is automatically updated. PROB parameter is stored in
/// Probabilities list. The default probability is set as unknown. Mixing
/// known and unknown probabilities in successor list is not allowed. When all
/// successors have unknown probabilities, 1 / N is returned as the
/// probability for each successor, where N is the number of successors.
///
/// Note that duplicate Machine CFG edges are not allowed.
void addSuccessor(MachineBasicBlock *Succ,
BranchProbability Prob = BranchProbability::getUnknown());
/// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
/// of Succ is automatically updated. The probability is not provided because
/// BPI is not available (e.g. -O0 is used), in which case edge probabilities
/// won't be used. Using this interface can save some space.
void addSuccessorWithoutProb(MachineBasicBlock *Succ);
/// Set successor probability of a given iterator.
void setSuccProbability(succ_iterator I, BranchProbability Prob);
/// Normalize probabilities of all successors so that the sum of them becomes
/// one. This is usually done when the current update on this MBB is done, and
/// the sum of its successors' probabilities is not guaranteed to be one. The
/// user is responsible for the correct use of this function.
/// MBB::removeSuccessor() has an option to do this automatically.
void normalizeSuccProbs() {
BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end());
}
/// Validate successors' probabilities and check if the sum of them is
/// approximate one. This only works in DEBUG mode.
void validateSuccProbs() const;
/// Remove successor from the successors list of this MachineBasicBlock. The
/// Predecessors list of Succ is automatically updated.
/// If NormalizeSuccProbs is true, then normalize successors' probabilities
/// after the successor is removed.
void removeSuccessor(MachineBasicBlock *Succ,
bool NormalizeSuccProbs = false);
/// Remove specified successor from the successors list of this
/// MachineBasicBlock. The Predecessors list of Succ is automatically updated.
/// If NormalizeSuccProbs is true, then normalize successors' probabilities
/// after the successor is removed.
/// Return the iterator to the element after the one removed.
succ_iterator removeSuccessor(succ_iterator I,
bool NormalizeSuccProbs = false);
/// Replace successor OLD with NEW and update probability info.
void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New);
/// Copy a successor (and any probability info) from original block to this
/// block's. Uses an iterator into the original blocks successors.
///
/// This is useful when doing a partial clone of successors. Afterward, the
/// probabilities may need to be normalized.
void copySuccessor(const MachineBasicBlock *Orig, succ_iterator I);
/// Split the old successor into old plus new and updates the probability
/// info.
void splitSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New,
bool NormalizeSuccProbs = false);
/// Transfers all the successors from MBB to this machine basic block (i.e.,
/// copies all the successors FromMBB and remove all the successors from
/// FromMBB).
void transferSuccessors(MachineBasicBlock *FromMBB);
/// Transfers all the successors, as in transferSuccessors, and update PHI
/// operands in the successor blocks which refer to FromMBB to refer to this.
void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB);
/// Return true if any of the successors have probabilities attached to them.
bool hasSuccessorProbabilities() const { return !Probs.empty(); }
/// Return true if the specified MBB is a predecessor of this block.
bool isPredecessor(const MachineBasicBlock *MBB) const;
/// Return true if the specified MBB is a successor of this block.
bool isSuccessor(const MachineBasicBlock *MBB) const;
/// Return true if the specified MBB will be emitted immediately after this
/// block, such that if this block exits by falling through, control will
/// transfer to the specified MBB. Note that MBB need not be a successor at
/// all, for example if this block ends with an unconditional branch to some
/// other block.
bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
/// Return the successor of this block if it has a single successor.
/// Otherwise return a null pointer.
///
const MachineBasicBlock *getSingleSuccessor() const;
MachineBasicBlock *getSingleSuccessor() {
return const_cast<MachineBasicBlock *>(
static_cast<const MachineBasicBlock *>(this)->getSingleSuccessor());
}
/// Return the predecessor of this block if it has a single predecessor.
/// Otherwise return a null pointer.
///
const MachineBasicBlock *getSinglePredecessor() const;
MachineBasicBlock *getSinglePredecessor() {
return const_cast<MachineBasicBlock *>(
static_cast<const MachineBasicBlock *>(this)->getSinglePredecessor());
}
/// Return the fallthrough block if the block can implicitly
/// transfer control to the block after it by falling off the end of
/// it. If an explicit branch to the fallthrough block is not allowed,
/// set JumpToFallThrough to be false. Non-null return is a conservative
/// answer.
MachineBasicBlock *getFallThrough(bool JumpToFallThrough = true);
/// Return the fallthrough block if the block can implicitly
/// transfer control to it's successor, whether by a branch or
/// a fallthrough. Non-null return is a conservative answer.
MachineBasicBlock *getLogicalFallThrough() { return getFallThrough(false); }
/// Return true if the block can implicitly transfer control to the
/// block after it by falling off the end of it. This should return
/// false if it can reach the block after it, but it uses an
/// explicit branch to do so (e.g., a table jump). True is a
/// conservative answer.
bool canFallThrough();
/// Returns a pointer to the first instruction in this block that is not a
/// PHINode instruction. When adding instructions to the beginning of the
/// basic block, they should be added before the returned value, not before
/// the first instruction, which might be PHI.
/// Returns end() is there's no non-PHI instruction.
iterator getFirstNonPHI();
const_iterator getFirstNonPHI() const {
return const_cast<MachineBasicBlock *>(this)->getFirstNonPHI();
}
/// Return the first instruction in MBB after I that is not a PHI or a label.
/// This is the correct point to insert lowered copies at the beginning of a
/// basic block that must be before any debugging information.
iterator SkipPHIsAndLabels(iterator I);
/// Return the first instruction in MBB after I that is not a PHI, label or
/// debug. This is the correct point to insert copies at the beginning of a
/// basic block. \p Reg is the register being used by a spill or defined for a
/// restore/split during register allocation.
iterator SkipPHIsLabelsAndDebug(iterator I, Register Reg = Register(),
bool SkipPseudoOp = true);
/// Returns an iterator to the first terminator instruction of this basic
/// block. If a terminator does not exist, it returns end().
iterator getFirstTerminator();
const_iterator getFirstTerminator() const {
return const_cast<MachineBasicBlock *>(this)->getFirstTerminator();
}
/// Same getFirstTerminator but it ignores bundles and return an
/// instr_iterator instead.
instr_iterator getFirstInstrTerminator();
/// Finds the first terminator in a block by scanning forward. This can handle
/// cases in GlobalISel where there may be non-terminator instructions between
/// terminators, for which getFirstTerminator() will not work correctly.
iterator getFirstTerminatorForward();
/// Returns an iterator to the first non-debug instruction in the basic block,
/// or end(). Skip any pseudo probe operation if \c SkipPseudoOp is true.
/// Pseudo probes are like debug instructions which do not turn into real
/// machine code. We try to use the function to skip both debug instructions
/// and pseudo probe operations to avoid API proliferation. This should work
/// most of the time when considering optimizing the rest of code in the
/// block, except for certain cases where pseudo probes are designed to block
/// the optimizations. For example, code merge like optimizations are supposed
/// to be blocked by pseudo probes for better AutoFDO profile quality.
/// Therefore, they should be considered as a valid instruction when this
/// function is called in a context of such optimizations. On the other hand,
/// \c SkipPseudoOp should be true when it's used in optimizations that
/// unlikely hurt profile quality, e.g., without block merging. The default
/// value of \c SkipPseudoOp is set to true to maximize code quality in
/// general, with an explict false value passed in in a few places like branch
/// folding and if-conversion to favor profile quality.
iterator getFirstNonDebugInstr(bool SkipPseudoOp = true);
const_iterator getFirstNonDebugInstr(bool SkipPseudoOp = true) const {
return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr(
SkipPseudoOp);
}
/// Returns an iterator to the last non-debug instruction in the basic block,
/// or end(). Skip any pseudo operation if \c SkipPseudoOp is true.
/// Pseudo probes are like debug instructions which do not turn into real
/// machine code. We try to use the function to skip both debug instructions
/// and pseudo probe operations to avoid API proliferation. This should work
/// most of the time when considering optimizing the rest of code in the
/// block, except for certain cases where pseudo probes are designed to block
/// the optimizations. For example, code merge like optimizations are supposed
/// to be blocked by pseudo probes for better AutoFDO profile quality.
/// Therefore, they should be considered as a valid instruction when this
/// function is called in a context of such optimizations. On the other hand,
/// \c SkipPseudoOp should be true when it's used in optimizations that
/// unlikely hurt profile quality, e.g., without block merging. The default
/// value of \c SkipPseudoOp is set to true to maximize code quality in
/// general, with an explict false value passed in in a few places like branch
/// folding and if-conversion to favor profile quality.
iterator getLastNonDebugInstr(bool SkipPseudoOp = true);
const_iterator getLastNonDebugInstr(bool SkipPseudoOp = true) const {
return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr(
SkipPseudoOp);
}
/// Convenience function that returns true if the block ends in a return
/// instruction.
bool isReturnBlock() const {
return !empty() && back().isReturn();
}
/// Convenience function that returns true if the bock ends in a EH scope
/// return instruction.
bool isEHScopeReturnBlock() const {
return !empty() && back().isEHScopeReturn();
}
/// Split a basic block into 2 pieces at \p SplitPoint. A new block will be
/// inserted after this block, and all instructions after \p SplitInst moved
/// to it (\p SplitInst will be in the original block). If \p LIS is provided,
/// LiveIntervals will be appropriately updated. \return the newly inserted
/// block.
///
/// If \p UpdateLiveIns is true, this will ensure the live ins list is
/// accurate, including for physreg uses/defs in the original block.
MachineBasicBlock *splitAt(MachineInstr &SplitInst, bool UpdateLiveIns = true,
LiveIntervals *LIS = nullptr);
/// Split the critical edge from this block to the given successor block, and
/// return the newly created block, or null if splitting is not possible.
///
/// This function updates LiveVariables, MachineDominatorTree, and
/// MachineLoopInfo, as applicable.
MachineBasicBlock *
SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P,
std::vector<SparseBitVector<>> *LiveInSets = nullptr) {
return SplitCriticalEdge(Succ, &P, nullptr, LiveInSets);
}
MachineBasicBlock *
SplitCriticalEdge(MachineBasicBlock *Succ,
MachineFunctionAnalysisManager &MFAM,
std::vector<SparseBitVector<>> *LiveInSets = nullptr) {
return SplitCriticalEdge(Succ, nullptr, &MFAM, LiveInSets);
}
/// Check if the edge between this block and the given successor \p
/// Succ, can be split. If this returns true a subsequent call to
/// SplitCriticalEdge is guaranteed to return a valid basic block if
/// no changes occurred in the meantime.
bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const;
void pop_front() { Insts.pop_front(); }
void pop_back() { Insts.pop_back(); }
void push_back(MachineInstr *MI) { Insts.push_back(MI); }
/// Insert MI into the instruction list before I, possibly inside a bundle.
///
/// If the insertion point is inside a bundle, MI will be added to the bundle,
/// otherwise MI will not be added to any bundle. That means this function
/// alone can't be used to prepend or append instructions to bundles. See
/// MIBundleBuilder::insert() for a more reliable way of doing that.
instr_iterator insert(instr_iterator I, MachineInstr *M);
/// Insert a range of instructions into the instruction list before I.
template<typename IT>
void insert(iterator I, IT S, IT E) {
assert((I == end() || I->getParent() == this) &&
"iterator points outside of basic block");
Insts.insert(I.getInstrIterator(), S, E);
}
/// Insert MI into the instruction list before I.
iterator insert(iterator I, MachineInstr *MI) {
assert((I == end() || I->getParent() == this) &&
"iterator points outside of basic block");
assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
"Cannot insert instruction with bundle flags");
return Insts.insert(I.getInstrIterator(), MI);
}
/// Insert MI into the instruction list after I.
iterator insertAfter(iterator I, MachineInstr *MI) {
assert((I == end() || I->getParent() == this) &&
"iterator points outside of basic block");
assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
"Cannot insert instruction with bundle flags");
return Insts.insertAfter(I.getInstrIterator(), MI);
}
/// If I is bundled then insert MI into the instruction list after the end of
/// the bundle, otherwise insert MI immediately after I.
instr_iterator insertAfterBundle(instr_iterator I, MachineInstr *MI) {
assert((I == instr_end() || I->getParent() == this) &&
"iterator points outside of basic block");
assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
"Cannot insert instruction with bundle flags");
while (I->isBundledWithSucc())
++I;
return Insts.insertAfter(I, MI);
}
/// Remove an instruction from the instruction list and delete it.
///
/// If the instruction is part of a bundle, the other instructions in the
/// bundle will still be bundled after removing the single instruction.
instr_iterator erase(instr_iterator I);
/// Remove an instruction from the instruction list and delete it.
///
/// If the instruction is part of a bundle, the other instructions in the
/// bundle will still be bundled after removing the single instruction.
instr_iterator erase_instr(MachineInstr *I) {
return erase(instr_iterator(I));
}
/// Remove a range of instructions from the instruction list and delete them.
iterator erase(iterator I, iterator E) {
return Insts.erase(I.getInstrIterator(), E.getInstrIterator());
}
/// Remove an instruction or bundle from the instruction list and delete it.
///
/// If I points to a bundle of instructions, they are all erased.
iterator erase(iterator I) {
return erase(I, std::next(I));
}
/// Remove an instruction from the instruction list and delete it.
///
/// If I is the head of a bundle of instructions, the whole bundle will be
/// erased.
iterator erase(MachineInstr *I) {
return erase(iterator(I));
}
/// Remove the unbundled instruction from the instruction list without
/// deleting it.
///
/// This function can not be used to remove bundled instructions, use
/// remove_instr to remove individual instructions from a bundle.
MachineInstr *remove(MachineInstr *I) {
assert(!I->isBundled() && "Cannot remove bundled instructions");
return Insts.remove(instr_iterator(I));
}
/// Remove the possibly bundled instruction from the instruction list
/// without deleting it.
///
/// If the instruction is part of a bundle, the other instructions in the
/// bundle will still be bundled after removing the single instruction.
MachineInstr *remove_instr(MachineInstr *I);
void clear() {
Insts.clear();
}
/// Take an instruction from MBB 'Other' at the position From, and insert it
/// into this MBB right before 'Where'.
///
/// If From points to a bundle of instructions, the whole bundle is moved.
void splice(iterator Where, MachineBasicBlock *Other, iterator From) {
// The range splice() doesn't allow noop moves, but this one does.
if (Where != From)
splice(Where, Other, From, std::next(From));
}
/// Take a block of instructions from MBB 'Other' in the range [From, To),
/// and insert them into this MBB right before 'Where'.
///
/// The instruction at 'Where' must not be included in the range of
/// instructions to move.
void splice(iterator Where, MachineBasicBlock *Other,
iterator From, iterator To) {
Insts.splice(Where.getInstrIterator(), Other->Insts,
From.getInstrIterator(), To.getInstrIterator());
}
/// This method unlinks 'this' from the containing function, and returns it,
/// but does not delete it.
MachineBasicBlock *removeFromParent();
/// This method unlinks 'this' from the containing function and deletes it.
void eraseFromParent();
/// Given a machine basic block that branched to 'Old', change the code and
/// CFG so that it branches to 'New' instead.
void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
/// Update all phi nodes in this basic block to refer to basic block \p New
/// instead of basic block \p Old.
void replacePhiUsesWith(MachineBasicBlock *Old, MachineBasicBlock *New);
/// Find the next valid DebugLoc starting at MBBI, skipping any debug
/// instructions. Return UnknownLoc if there is none.
DebugLoc findDebugLoc(instr_iterator MBBI);
DebugLoc findDebugLoc(iterator MBBI) {
return findDebugLoc(MBBI.getInstrIterator());
}
/// Has exact same behavior as @ref findDebugLoc (it also searches towards the
/// end of this MBB) except that this function takes a reverse iterator to
/// identify the starting MI.
DebugLoc rfindDebugLoc(reverse_instr_iterator MBBI);
DebugLoc rfindDebugLoc(reverse_iterator MBBI) {
return rfindDebugLoc(MBBI.getInstrIterator());
}
/// Find the previous valid DebugLoc preceding MBBI, skipping any debug
/// instructions. It is possible to find the last DebugLoc in the MBB using
/// findPrevDebugLoc(instr_end()). Return UnknownLoc if there is none.
DebugLoc findPrevDebugLoc(instr_iterator MBBI);
DebugLoc findPrevDebugLoc(iterator MBBI) {
return findPrevDebugLoc(MBBI.getInstrIterator());
}
/// Has exact same behavior as @ref findPrevDebugLoc (it also searches towards
/// the beginning of this MBB) except that this function takes reverse
/// iterator to identify the starting MI. A minor difference compared to
/// findPrevDebugLoc is that we can't start scanning at "instr_end".
DebugLoc rfindPrevDebugLoc(reverse_instr_iterator MBBI);
DebugLoc rfindPrevDebugLoc(reverse_iterator MBBI) {
return rfindPrevDebugLoc(MBBI.getInstrIterator());
}
/// Find and return the merged DebugLoc of the branch instructions of the
/// block. Return UnknownLoc if there is none.
DebugLoc findBranchDebugLoc();
/// Possible outcome of a register liveness query to computeRegisterLiveness()
enum LivenessQueryResult {
LQR_Live, ///< Register is known to be (at least partially) live.
LQR_Dead, ///< Register is known to be fully dead.
LQR_Unknown ///< Register liveness not decidable from local neighborhood.
};
/// Return whether (physical) register \p Reg has been defined and not
/// killed as of just before \p Before.
///
/// Search is localised to a neighborhood of \p Neighborhood instructions
/// before (searching for defs or kills) and \p Neighborhood instructions
/// after (searching just for defs) \p Before.
///
/// \p Reg must be a physical register.
LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI,
MCRegister Reg,
const_iterator Before,
unsigned Neighborhood = 10) const;
// Debugging methods.
void dump() const;
void print(raw_ostream &OS, const SlotIndexes * = nullptr,
bool IsStandalone = true) const;
void print(raw_ostream &OS, ModuleSlotTracker &MST,
const SlotIndexes * = nullptr, bool IsStandalone = true) const;
enum PrintNameFlag {
PrintNameIr = (1 << 0), ///< Add IR name where available
PrintNameAttributes = (1 << 1), ///< Print attributes
};
void printName(raw_ostream &os, unsigned printNameFlags = PrintNameIr,
ModuleSlotTracker *moduleSlotTracker = nullptr) const;
// Printing method used by LoopInfo.
void printAsOperand(raw_ostream &OS, bool PrintType = true) const;
/// MachineBasicBlocks are uniquely numbered at the function level, unless
/// they're not in a MachineFunction yet, in which case this will return -1.
int getNumber() const { return Number; }
void setNumber(int N) { Number = N; }
/// Return the call frame size on entry to this basic block.
unsigned getCallFrameSize() const { return CallFrameSize; }
/// Set the call frame size on entry to this basic block.
void setCallFrameSize(unsigned N) { CallFrameSize = N; }
/// Return the MCSymbol for this basic block.
MCSymbol *getSymbol() const;
/// Return the EHCatchret Symbol for this basic block.
MCSymbol *getEHCatchretSymbol() const;
std::optional<uint64_t> getIrrLoopHeaderWeight() const {
return IrrLoopHeaderWeight;
}
void setIrrLoopHeaderWeight(uint64_t Weight) {
IrrLoopHeaderWeight = Weight;
}
/// Return probability of the edge from this block to MBB. This method should
/// NOT be called directly, but by using getEdgeProbability method from
/// MachineBranchProbabilityInfo class.
BranchProbability getSuccProbability(const_succ_iterator Succ) const;
private:
/// Return probability iterator corresponding to the I successor iterator.
probability_iterator getProbabilityIterator(succ_iterator I);
const_probability_iterator
getProbabilityIterator(const_succ_iterator I) const;
friend class MachineBranchProbabilityInfo;
friend class MIPrinter;
// Methods used to maintain doubly linked list of blocks...
friend struct ilist_callback_traits<MachineBasicBlock>;
// Machine-CFG mutators
/// Add Pred as a predecessor of this MachineBasicBlock. Don't do this
/// unless you know what you're doing, because it doesn't update Pred's
/// successors list. Use Pred->addSuccessor instead.
void addPredecessor(MachineBasicBlock *Pred);
/// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this
/// unless you know what you're doing, because it doesn't update Pred's
/// successors list. Use Pred->removeSuccessor instead.
void removePredecessor(MachineBasicBlock *Pred);
// Helper method for new pass manager migration.
MachineBasicBlock *
SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P,
MachineFunctionAnalysisManager *MFAM,
std::vector<SparseBitVector<>> *LiveInSets);
};
raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB);
/// Prints a machine basic block reference.
///
/// The format is:
/// %bb.5 - a machine basic block with MBB.getNumber() == 5.
///
/// Usage: OS << printMBBReference(MBB) << '\n';
Printable printMBBReference(const MachineBasicBlock &MBB);
// This is useful when building IndexedMaps keyed on basic block pointers.
struct MBB2NumberFunctor {
using argument_type = const MachineBasicBlock *;
unsigned operator()(const MachineBasicBlock *MBB) const {
return MBB->getNumber();
}
};
//===--------------------------------------------------------------------===//
// GraphTraits specializations for machine basic block graphs (machine-CFGs)
//===--------------------------------------------------------------------===//
// Provide specializations of GraphTraits to be able to treat a
// MachineFunction as a graph of MachineBasicBlocks.
//
template <> struct GraphTraits<MachineBasicBlock *> {
using NodeRef = MachineBasicBlock *;
using ChildIteratorType = MachineBasicBlock::succ_iterator;
static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; }
static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); }
static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); }
};
template <> struct GraphTraits<const MachineBasicBlock *> {
using NodeRef = const MachineBasicBlock *;
using ChildIteratorType = MachineBasicBlock::const_succ_iterator;
static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; }
static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); }
static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); }
};
// Provide specializations of GraphTraits to be able to treat a
// MachineFunction as a graph of MachineBasicBlocks and to walk it
// in inverse order. Inverse order for a function is considered
// to be when traversing the predecessor edges of a MBB
// instead of the successor edges.
//
template <> struct GraphTraits<Inverse<MachineBasicBlock*>> {
using NodeRef = MachineBasicBlock *;
using ChildIteratorType = MachineBasicBlock::pred_iterator;
static NodeRef getEntryNode(Inverse<MachineBasicBlock *> G) {
return G.Graph;
}
static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); }
static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); }
};
template <> struct GraphTraits<Inverse<const MachineBasicBlock*>> {
using NodeRef = const MachineBasicBlock *;
using ChildIteratorType = MachineBasicBlock::const_pred_iterator;
static NodeRef getEntryNode(Inverse<const MachineBasicBlock *> G) {
return G.Graph;
}
static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); }
static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); }
};
// These accessors are handy for sharing templated code between IR and MIR.
inline auto successors(const MachineBasicBlock *BB) { return BB->successors(); }
inline auto predecessors(const MachineBasicBlock *BB) {
return BB->predecessors();
}
/// MachineInstrSpan provides an interface to get an iteration range
/// containing the instruction it was initialized with, along with all
/// those instructions inserted prior to or following that instruction
/// at some point after the MachineInstrSpan is constructed.
class MachineInstrSpan {
MachineBasicBlock &MBB;
MachineBasicBlock::iterator I, B, E;
public:
MachineInstrSpan(MachineBasicBlock::iterator I, MachineBasicBlock *BB)
: MBB(*BB), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)),
E(std::next(I)) {
assert(I == BB->end() || I->getParent() == BB);
}
MachineBasicBlock::iterator begin() {
return B == MBB.end() ? MBB.begin() : std::next(B);
}
MachineBasicBlock::iterator end() { return E; }
bool empty() { return begin() == end(); }
MachineBasicBlock::iterator getInitial() { return I; }
};
/// Increment \p It until it points to a non-debug instruction or to \p End
/// and return the resulting iterator. This function should only be used
/// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
/// const_instr_iterator} and the respective reverse iterators.
template <typename IterT>
inline IterT skipDebugInstructionsForward(IterT It, IterT End,
bool SkipPseudoOp = true) {
while (It != End &&
(It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe())))
++It;
return It;
}
/// Decrement \p It until it points to a non-debug instruction or to \p Begin
/// and return the resulting iterator. This function should only be used
/// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
/// const_instr_iterator} and the respective reverse iterators.
template <class IterT>
inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin,
bool SkipPseudoOp = true) {
while (It != Begin &&
(It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe())))
--It;
return It;
}
/// Increment \p It, then continue incrementing it while it points to a debug
/// instruction. A replacement for std::next.
template <typename IterT>
inline IterT next_nodbg(IterT It, IterT End, bool SkipPseudoOp = true) {
return skipDebugInstructionsForward(std::next(It), End, SkipPseudoOp);
}
/// Decrement \p It, then continue decrementing it while it points to a debug
/// instruction. A replacement for std::prev.
template <typename IterT>
inline IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp = true) {
return skipDebugInstructionsBackward(std::prev(It), Begin, SkipPseudoOp);
}
/// Construct a range iterator which begins at \p It and moves forwards until
/// \p End is reached, skipping any debug instructions.
template <typename IterT>
inline auto instructionsWithoutDebug(IterT It, IterT End,
bool SkipPseudoOp = true) {
return make_filter_range(make_range(It, End), [=](const MachineInstr &MI) {
return !MI.isDebugInstr() && !(SkipPseudoOp && MI.isPseudoProbe());
});
}
} // end namespace llvm
#endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H
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