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