Server : Apache/2.4.41 (Ubuntu) System : Linux absol.cf 5.4.0-198-generic #218-Ubuntu SMP Fri Sep 27 20:18:53 UTC 2024 x86_64 User : www-data ( 33) PHP Version : 7.4.33 Disable Function : pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wifcontinued,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_get_handler,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,pcntl_async_signals,pcntl_unshare, Directory :  /usr/lib/llvm-6.0/build/Release/include/llvm/Analysis/

Upload File : current_dir [ Writeable ] document_root [ Writeable ]

//===- llvm/Analysis/OrderedBasicBlock.h --------------------- -*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the OrderedBasicBlock class. OrderedBasicBlock maintains
// an interface where clients can query if one instruction comes before another
// in a BasicBlock. Since BasicBlock currently lacks a reliable way to query
// relative position between instructions one can use OrderedBasicBlock to do
// such queries. OrderedBasicBlock is lazily built on a source BasicBlock and
// maintains an internal Instruction -> Position map. A OrderedBasicBlock
// instance should be discarded whenever the source BasicBlock changes.
//
// It's currently used by the CaptureTracker in order to find relative
// positions of a pair of instructions inside a BasicBlock.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_ORDEREDBASICBLOCK_H
#define LLVM_ANALYSIS_ORDEREDBASICBLOCK_H

#include "llvm/ADT/DenseMap.h"
#include "llvm/IR/BasicBlock.h"

namespace llvm {

class Instruction;
class BasicBlock;

class OrderedBasicBlock {
private:
  /// \brief Map a instruction to its position in a BasicBlock.
  SmallDenseMap<const Instruction *, unsigned, 32> NumberedInsts;

  /// \brief Keep track of last instruction inserted into \p NumberedInsts.
  /// It speeds up queries for uncached instructions by providing a start point
  /// for new queries in OrderedBasicBlock::comesBefore.
  BasicBlock::const_iterator LastInstFound;

  /// \brief The position/number to tag the next instruction to be found.
  unsigned NextInstPos;

  /// \brief The source BasicBlock to map.
  const BasicBlock *BB;

  /// \brief Given no cached results, find if \p A comes before \p B in \p BB.
  /// Cache and number out instruction while walking \p BB.
  bool comesBefore(const Instruction *A, const Instruction *B);

public:
  OrderedBasicBlock(const BasicBlock *BasicB);

  /// \brief Find out whether \p A dominates \p B, meaning whether \p A
  /// comes before \p B in \p BB. This is a simplification that considers
  /// cached instruction positions and ignores other basic blocks, being
  /// only relevant to compare relative instructions positions inside \p BB.
  /// Returns false for A == B.
  bool dominates(const Instruction *A, const Instruction *B);
};

} // End llvm namespace

#endif