1//===-- DifferenceEngine.h - Module comparator ------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This header defines the interface to the LLVM difference engine,
10// which structurally compares functions within a module.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_TOOLS_LLVM_DIFF_DIFFERENCEENGINE_H
15#define LLVM_TOOLS_LLVM_DIFF_DIFFERENCEENGINE_H
16
17#include "DiffConsumer.h"
18#include "DiffLog.h"
19#include "llvm/ADT/StringRef.h"
20#include <utility>
21
22namespace llvm {
23 class Function;
24 class GlobalValue;
25 class Instruction;
26 class LLVMContext;
27 class Module;
28 class Twine;
29 class Value;
30
31 /// A class for performing structural comparisons of LLVM assembly.
32 class DifferenceEngine {
33 public:
34 /// A RAII object for recording the current context.
35 struct Context {
36 Context(DifferenceEngine &Engine, const Value *L, const Value *R)
37 : Engine(Engine) {
38 Engine.consumer.enterContext(Left: L, Right: R);
39 }
40
41 ~Context() {
42 Engine.consumer.exitContext();
43 }
44
45 private:
46 DifferenceEngine &Engine;
47 };
48
49 /// An oracle for answering whether two values are equivalent as
50 /// operands.
51 class Oracle {
52 virtual void anchor();
53 public:
54 virtual bool operator()(const Value *L, const Value *R) = 0;
55
56 protected:
57 virtual ~Oracle() {}
58 };
59
60 DifferenceEngine(Consumer &consumer)
61 : consumer(consumer), globalValueOracle(nullptr) {}
62
63 void diff(const Module *L, const Module *R);
64 void diff(const Function *L, const Function *R);
65 void log(StringRef text) {
66 consumer.log(Text: text);
67 }
68 LogBuilder logf(StringRef text) {
69 return LogBuilder(consumer, text);
70 }
71 Consumer& getConsumer() const { return consumer; }
72
73 /// Installs an oracle to decide whether two global values are
74 /// equivalent as operands. Without an oracle, global values are
75 /// considered equivalent as operands precisely when they have the
76 /// same name.
77 void setGlobalValueOracle(Oracle *oracle) {
78 globalValueOracle = oracle;
79 }
80
81 /// Determines whether two global values are equivalent.
82 bool equivalentAsOperands(const GlobalValue *L, const GlobalValue *R);
83
84 private:
85 Consumer &consumer;
86 Oracle *globalValueOracle;
87 };
88}
89
90#endif
91