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//===- llvm/Analysis/Trace.h - Represent one trace of LLVM code -*- 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 class represents a single trace of LLVM basic blocks.  A trace is a

// single entry, multiple exit, region of code that is often hot.  Trace-based

// optimizations treat traces almost like they are a large, strange, basic

// block: because the trace path is assumed to be hot, optimizations for the

// fall-through path are made at the expense of the non-fall-through paths.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_TRACE_H

#define LLVM_ANALYSIS_TRACE_H

#include <cassert>

#include <vector>

namespace llvm {

class BasicBlock;

class Function;

class Module;

class raw_ostream;

class Trace {

  using BasicBlockListType = std::vector<BasicBlock *>;

  BasicBlockListType BasicBlocks;

public:

  /// Trace ctor - Make a new trace from a vector of basic blocks,

  /// residing in the function which is the parent of the first

  /// basic block in the vector.

  Trace(const std::vector<BasicBlock *> &vBB) : BasicBlocks (vBB) {}

  /// getEntryBasicBlock - Return the entry basic block (first block)

  /// of the trace.

  BasicBlock *getEntryBasicBlock () const { return BasicBlocks[0]; }

  /// operator[]/getBlock - Return basic block N in the trace.

  BasicBlock *operator[](unsigned i) const { return BasicBlocks[i]; }

  BasicBlock *getBlock(unsigned i)   const { return BasicBlocks[i]; }

  /// getFunction - Return this trace's parent function.

  Function *getFunction () const;

  /// getModule - Return this Module that contains this trace's parent

  /// function.

  Module *getModule () const;

  /// getBlockIndex - Return the index of the specified basic block in the

  /// trace, or -1 if it is not in the trace.

  int getBlockIndex(const BasicBlock *X) const {

    for (unsigned i = 0, e = BasicBlocks.size(); i != e; ++i)

      if (BasicBlocks[i] == X)

        return i;

    return -1;

  }

  /// contains - Returns true if this trace contains the given basic

  /// block.

  bool contains(const BasicBlock *X) const {

    return getBlockIndex(X) != -1;

  }

  /// Returns true if B1 occurs before B2 in the trace, or if it is the same

  /// block as B2..  Both blocks must be in the trace.

  bool dominates(const BasicBlock *B1, const BasicBlock *B2) const {

    int B1Idx = getBlockIndex(B1), B2Idx = getBlockIndex(B2);

    assert(B1Idx != -1 && B2Idx != -1 && "Block is not in the trace!");

    return B1Idx <= B2Idx;

  }

  // BasicBlock iterators...

  using iterator = BasicBlockListType::iterator;

  using const_iterator = BasicBlockListType::const_iterator;

  using reverse_iterator = std::reverse_iterator<iterator>;

  using const_reverse_iterator = std::reverse_iterator<const_iterator>;

  iterator                begin()       { return BasicBlocks.begin(); }

  const_iterator          begin() const { return BasicBlocks.begin(); }

  iterator                end  ()       { return BasicBlocks.end();   }

  const_iterator          end  () const { return BasicBlocks.end();   }

  reverse_iterator       rbegin()       { return BasicBlocks.rbegin(); }

  const_reverse_iterator rbegin() const { return BasicBlocks.rbegin(); }

  reverse_iterator       rend  ()       { return BasicBlocks.rend();   }

  const_reverse_iterator rend  () const { return BasicBlocks.rend();   }

  unsigned                 size() const { return BasicBlocks.size(); }

  bool                    empty() const { return BasicBlocks.empty(); }

  iterator erase(iterator q)               { return BasicBlocks.erase (q); }

  iterator erase(iterator q1, iterator q2) { return BasicBlocks.erase (q1, q2); }

  /// print - Write trace to output stream.

  void print(raw_ostream &O) const;

  /// dump - Debugger convenience method; writes trace to standard error

  /// output stream.

  void dump() const;

};

} // end namespace llvm

#endif // LLVM_ANALYSIS_TRACE_H