Trace.h revision 688ed8583eaa1544e8e53b039b2b8284d2e9268a 
1//===- llvm/Analysis/Trace.h - Represent one trace of LLVM code -*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This class represents a single trace of LLVM basic blocks.  A trace is a
11// single entry, multiple exit, region of code that is often hot.  Trace-based
12// optimizations treat traces almost like they are a large, strange, basic
13// block: because the trace path is assumed to be hot, optimizations for the
14// fall-through path are made at the expense of the non-fall-through paths.
15//
16//===----------------------------------------------------------------------===//
17
18#ifndef LLVM_ANALYSIS_TRACE_H
19#define LLVM_ANALYSIS_TRACE_H
20
21#include <vector>
22#include <cassert>
23#include <iosfwd>
24
25namespace llvm {
26  class BasicBlock;
27  class Function;
28  class Module;
29
30class Trace {
31  typedef std::vector<BasicBlock *> BasicBlockListType;
32  BasicBlockListType BasicBlocks;
33
34public:
35  /// Trace ctor - Make a new trace from a vector of basic blocks,
36  /// residing in the function which is the parent of the first
37  /// basic block in the vector.
38  ///
39  Trace(const std::vector<BasicBlock *> &vBB) : BasicBlocks (vBB) {}
40
41  /// getEntryBasicBlock - Return the entry basic block (first block)
42  /// of the trace.
43  ///
44  BasicBlock *getEntryBasicBlock () const { return BasicBlocks[0]; }
45
46  /// operator[]/getBlock - Return basic block N in the trace.
47  ///
48  BasicBlock *operator[](unsigned i) const { return BasicBlocks[i]; }
49  BasicBlock *getBlock(unsigned i)   const { return BasicBlocks[i]; }
50
51  /// getFunction - Return this trace's parent function.
52  ///
53  Function *getFunction () const;
54
55  /// getModule - Return this Module that contains this trace's parent
56  /// function.
57  ///
58  Module *getModule () const;
59
60  /// getBlockIndex - Return the index of the specified basic block in the
61  /// trace, or -1 if it is not in the trace.
62  int getBlockIndex(const BasicBlock *X) const {
63    for (unsigned i = 0, e = BasicBlocks.size(); i != e; ++i)
64      if (BasicBlocks[i] == X)
65        return i;
66    return -1;
67  }
68
69  /// contains - Returns true if this trace contains the given basic
70  /// block.
71  ///
72  bool contains(const BasicBlock *X) const {
73    return getBlockIndex(X) != -1;
74  }
75
76  /// Returns true if B1 occurs before B2 in the trace, or if it is the same
77  /// block as B2..  Both blocks must be in the trace.
78  ///
79  bool dominates(const BasicBlock *B1, const BasicBlock *B2) const {
80    int B1Idx = getBlockIndex(B1), B2Idx = getBlockIndex(B2);
81    assert(B1Idx != -1 && B2Idx != -1 && "Block is not in the trace!");
82    return B1Idx <= B2Idx;
83  }
84
85  // BasicBlock iterators...
86  typedef BasicBlockListType::iterator iterator;
87  typedef BasicBlockListType::const_iterator const_iterator;
88  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
89  typedef std::reverse_iterator<iterator> reverse_iterator;
90
91  iterator                begin()       { return BasicBlocks.begin(); }
92  const_iterator          begin() const { return BasicBlocks.begin(); }
93  iterator                end  ()       { return BasicBlocks.end();   }
94  const_iterator          end  () const { return BasicBlocks.end();   }
95
96  reverse_iterator       rbegin()       { return BasicBlocks.rbegin(); }
97  const_reverse_iterator rbegin() const { return BasicBlocks.rbegin(); }
98  reverse_iterator       rend  ()       { return BasicBlocks.rend();   }
99  const_reverse_iterator rend  () const { return BasicBlocks.rend();   }
100
101  unsigned                 size() const { return BasicBlocks.size(); }
102  bool                    empty() const { return BasicBlocks.empty(); }
103
104  iterator erase(iterator q)               { return BasicBlocks.erase (q); }
105  iterator erase(iterator q1, iterator q2) { return BasicBlocks.erase (q1, q2); }
106
107  /// print - Write trace to output stream.
108  ///
109  void print (std::ostream &O) const;
110  void print (std::ostream *O) const { if (O) print(*O); }
111
112  /// dump - Debugger convenience method; writes trace to standard error
113  /// output stream.
114  ///
115  void dump () const;
116};
117
118} // end namespace llvm
119
120#endif // TRACE_H
121