9b58b2e64b
Summary: The LBR only has information about taken branches and does not record information when a branch is not taken. In our CFG, we call these edges "fall-through" edges. This patch teaches llvm-flo how to infer fall-through edge frequencies. (cherry picked from FBD2536633)
229 lines
8.7 KiB
C++
229 lines
8.7 KiB
C++
//===--- BinaryBasicBlock.h - Interface for assembly-level basic block ----===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// TODO: memory management for instructions.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TOOLS_LLVM_FLO_BINARY_BASIC_BLOCK_H
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#define LLVM_TOOLS_LLVM_FLO_BINARY_BASIC_BLOCK_H
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#include "llvm/ADT/StringRef.h"
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#include "llvm/ADT/ilist.h"
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#include "llvm/MC/MCCodeEmitter.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/MC/MCInstPrinter.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Object/ObjectFile.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include <limits>
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namespace llvm {
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namespace flo {
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class BinaryFunction;
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/// The intention is to keep the structure similar to MachineBasicBlock as
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/// we might switch to it at some point.
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class BinaryBasicBlock {
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/// Label associated with the block.
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MCSymbol *Label{nullptr};
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/// Original offset in the function.
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uint64_t Offset{std::numeric_limits<uint64_t>::max()};
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/// Alignment requirements for the block.
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uint64_t Alignment{1};
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/// Number of times this basic block was executed.
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uint64_t ExecutionCount{COUNT_NO_PROFILE};
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/// Vector of all instructions in the block.
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std::vector<MCInst> Instructions;
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/// CFG information.
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std::vector<BinaryBasicBlock *> Predecessors;
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std::vector<BinaryBasicBlock *> Successors;
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struct BinaryBranchInfo {
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uint64_t Count;
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uint64_t MispredictedCount; /// number of branches mispredicted
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};
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/// Each successor has a corresponding BranchInfo entry in the list.
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std::vector<BinaryBranchInfo> BranchInfo;
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typedef std::vector<BinaryBranchInfo>::iterator branch_info_iterator;
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typedef std::vector<BinaryBranchInfo>::const_iterator
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const_branch_info_iterator;
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BinaryBasicBlock() {}
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explicit BinaryBasicBlock(
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MCSymbol *Label,
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uint64_t Offset = std::numeric_limits<uint64_t>::max())
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: Label(Label), Offset(Offset) {}
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explicit BinaryBasicBlock(uint64_t Offset)
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: Offset(Offset) {}
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// Exclusively managed by BinaryFunction.
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friend class BinaryFunction;
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friend bool operator<(const BinaryBasicBlock &LHS,
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const BinaryBasicBlock &RHS);
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public:
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static constexpr uint64_t COUNT_FALLTHROUGH_EDGE =
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std::numeric_limits<uint64_t>::max();
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static constexpr uint64_t COUNT_NO_PROFILE =
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std::numeric_limits<uint64_t>::max();
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// Instructions iterators.
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typedef std::vector<MCInst>::iterator iterator;
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typedef std::vector<MCInst>::const_iterator const_iterator;
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typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
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typedef std::reverse_iterator<iterator> reverse_iterator;
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MCInst &front() { return Instructions.front(); }
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MCInst &back() { return Instructions.back(); }
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const MCInst &front() const { return Instructions.front(); }
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const MCInst &back() const { return Instructions.back(); }
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iterator begin() { return Instructions.begin(); }
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const_iterator begin() const { return Instructions.begin(); }
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iterator end () { return Instructions.end(); }
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const_iterator end () const { return Instructions.end(); }
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reverse_iterator rbegin() { return Instructions.rbegin(); }
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const_reverse_iterator rbegin() const { return Instructions.rbegin(); }
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reverse_iterator rend () { return Instructions.rend(); }
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const_reverse_iterator rend () const { return Instructions.rend(); }
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// CFG iterators.
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typedef std::vector<BinaryBasicBlock *>::iterator pred_iterator;
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typedef std::vector<BinaryBasicBlock *>::const_iterator const_pred_iterator;
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typedef std::vector<BinaryBasicBlock *>::iterator succ_iterator;
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typedef std::vector<BinaryBasicBlock *>::const_iterator const_succ_iterator;
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typedef std::vector<BinaryBasicBlock *>::reverse_iterator
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pred_reverse_iterator;
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typedef std::vector<BinaryBasicBlock *>::const_reverse_iterator
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const_pred_reverse_iterator;
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typedef std::vector<BinaryBasicBlock *>::reverse_iterator
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succ_reverse_iterator;
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typedef std::vector<BinaryBasicBlock *>::const_reverse_iterator
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const_succ_reverse_iterator;
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pred_iterator pred_begin() { return Predecessors.begin(); }
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const_pred_iterator pred_begin() const { return Predecessors.begin(); }
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pred_iterator pred_end() { return Predecessors.end(); }
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const_pred_iterator pred_end() const { return Predecessors.end(); }
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pred_reverse_iterator pred_rbegin()
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{ return Predecessors.rbegin();}
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const_pred_reverse_iterator pred_rbegin() const
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{ return Predecessors.rbegin();}
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pred_reverse_iterator pred_rend()
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{ return Predecessors.rend(); }
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const_pred_reverse_iterator pred_rend() const
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{ return Predecessors.rend(); }
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unsigned pred_size() const {
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return (unsigned)Predecessors.size();
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}
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bool pred_empty() const { return Predecessors.empty(); }
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succ_iterator succ_begin() { return Successors.begin(); }
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const_succ_iterator succ_begin() const { return Successors.begin(); }
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succ_iterator succ_end() { return Successors.end(); }
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const_succ_iterator succ_end() const { return Successors.end(); }
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succ_reverse_iterator succ_rbegin()
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{ return Successors.rbegin(); }
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const_succ_reverse_iterator succ_rbegin() const
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{ return Successors.rbegin(); }
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succ_reverse_iterator succ_rend()
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{ return Successors.rend(); }
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const_succ_reverse_iterator succ_rend() const
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{ return Successors.rend(); }
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unsigned succ_size() const {
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return (unsigned)Successors.size();
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}
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bool succ_empty() const { return Successors.empty(); }
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inline iterator_range<pred_iterator> predecessors() {
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return iterator_range<pred_iterator>(pred_begin(), pred_end());
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}
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inline iterator_range<const_pred_iterator> predecessors() const {
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return iterator_range<const_pred_iterator>(pred_begin(), pred_end());
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}
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inline iterator_range<succ_iterator> successors() {
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return iterator_range<succ_iterator>(succ_begin(), succ_end());
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}
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inline iterator_range<const_succ_iterator> successors() const {
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return iterator_range<const_succ_iterator>(succ_begin(), succ_end());
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}
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/// Return symbol marking the start of this basic block.
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MCSymbol *getLabel() const {
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return Label;
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}
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/// Return local name for the block.
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StringRef getName() const {
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return Label->getName();
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}
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/// Add instruction at the end of this basic block.
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void addInstruction(MCInst &Inst) {
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Instructions.emplace_back(Inst);
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}
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/// Return required alignment for the block.
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uint64_t getAlignment() const {
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return Alignment;
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}
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/// Adds block to successor list, and also updates predecessor list for
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/// successor block.
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/// Set branch info for this path.
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void addSuccessor(BinaryBasicBlock *Succ,
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uint64_t Count = 0,
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uint64_t MispredictedCount = 0);
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/// Remove /p Succ basic block from the list of successors. Update the
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/// list of predecessors of /p Succ and update branch info.
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void removeSuccessor(BinaryBasicBlock *Succ);
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/// Return the information about the number of times this basic block was
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/// executed.
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///
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/// Return COUNT_NO_PROFILE if there's no profile info.
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uint64_t getExecutionCount() const {
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return ExecutionCount;
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}
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private:
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/// Adds predecessor to the BB. Most likely you don't need to call this.
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void addPredecessor(BinaryBasicBlock *Pred);
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/// Remove predecessor of the basic block. Don't use directly, instead
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/// use removeSuccessor() funciton.
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void removePredecessor(BinaryBasicBlock *Pred);
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};
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bool operator<(const BinaryBasicBlock &LHS, const BinaryBasicBlock &RHS);
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} // namespace flo
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} // namespace llvm
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#endif
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