1//===-- DifferenceEngine.h - Module comparator ------------------*- 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 header defines the interface to the LLVM difference engine,
11// which structurally compares functions within a module.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef _LLVM_DIFFERENCE_ENGINE_H_
16#define _LLVM_DIFFERENCE_ENGINE_H_
17
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/StringRef.h"
20#include "DiffLog.h"
21#include "DiffConsumer.h"
22
23#include <utility>
24
25namespace llvm {
26  class Function;
27  class GlobalValue;
28  class Instruction;
29  class LLVMContext;
30  class Module;
31  class Twine;
32  class Value;
33
34  /// A class for performing structural comparisons of LLVM assembly.
35  class DifferenceEngine {
36  public:
37    /// A RAII object for recording the current context.
38    struct Context {
39      Context(DifferenceEngine &Engine, Value *L, Value *R) : Engine(Engine) {
40        Engine.consumer.enterContext(L, R);
41      }
42
43      ~Context() {
44        Engine.consumer.exitContext();
45      }
46
47    private:
48      DifferenceEngine &Engine;
49    };
50
51    /// An oracle for answering whether two values are equivalent as
52    /// operands.
53    class Oracle {
54      virtual void anchor();
55    public:
56      virtual bool operator()(Value *L, Value *R) = 0;
57
58    protected:
59      virtual ~Oracle() {}
60    };
61
62    DifferenceEngine(Consumer &consumer)
63      : consumer(consumer), globalValueOracle(0) {}
64
65    void diff(Module *L, Module *R);
66    void diff(Function *L, Function *R);
67    void log(StringRef text) {
68      consumer.log(text);
69    }
70    LogBuilder logf(StringRef text) {
71      return LogBuilder(consumer, text);
72    }
73    Consumer& getConsumer() const { return consumer; }
74
75    /// Installs an oracle to decide whether two global values are
76    /// equivalent as operands.  Without an oracle, global values are
77    /// considered equivalent as operands precisely when they have the
78    /// same name.
79    void setGlobalValueOracle(Oracle *oracle) {
80      globalValueOracle = oracle;
81    }
82
83    /// Determines whether two global values are equivalent.
84    bool equivalentAsOperands(GlobalValue *L, GlobalValue *R);
85
86  private:
87    Consumer &consumer;
88    Oracle *globalValueOracle;
89  };
90}
91
92#endif
93