1 | //===- GenericSSAContext.h --------------------------------------*- 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 | /// \file |
9 | /// |
10 | /// This file defines the little GenericSSAContext<X> template class |
11 | /// that can be used to implement IR analyses as templates. |
12 | /// Specializing these templates allows the analyses to be used over |
13 | /// both LLVM IR and Machine IR. |
14 | /// |
15 | //===----------------------------------------------------------------------===// |
16 | |
17 | #ifndef LLVM_ADT_GENERICSSACONTEXT_H |
18 | #define LLVM_ADT_GENERICSSACONTEXT_H |
19 | |
20 | #include "llvm/Support/Printable.h" |
21 | |
22 | namespace llvm { |
23 | |
24 | template <typename, bool> class DominatorTreeBase; |
25 | template <typename> class SmallVectorImpl; |
26 | |
27 | namespace Intrinsic { |
28 | typedef unsigned ID; |
29 | } |
30 | |
31 | // Specializations of this template should provide the types used by the |
32 | // template GenericSSAContext below. |
33 | template <typename _FunctionT> struct GenericSSATraits; |
34 | |
35 | // Ideally this should have been a stateless traits class. But the print methods |
36 | // for Machine IR need access to the owning function. So we track that state in |
37 | // the template itself. |
38 | // |
39 | // We use FunctionT as a template argument and not GenericSSATraits to allow |
40 | // forward declarations using well-known typenames. |
41 | template <typename _FunctionT> class GenericSSAContext { |
42 | using SSATraits = GenericSSATraits<_FunctionT>; |
43 | const typename SSATraits::FunctionT *F; |
44 | |
45 | public: |
46 | // The smallest unit of the IR is a ValueT. The SSA context uses a ValueRefT, |
47 | // which is a pointer to a ValueT, since Machine IR does not have the |
48 | // equivalent of a ValueT. |
49 | using ValueRefT = typename SSATraits::ValueRefT; |
50 | |
51 | // The ConstValueRefT is needed to work with "const Value *", where const |
52 | // needs to bind to the pointee and not the pointer. |
53 | using ConstValueRefT = typename SSATraits::ConstValueRefT; |
54 | |
55 | // The null value for ValueRefT. For LLVM IR and MIR, this is simply the |
56 | // default constructed value. |
57 | static constexpr ValueRefT *ValueRefNull = {}; |
58 | |
59 | // An InstructionT usually defines one or more ValueT objects. |
60 | using InstructionT = typename SSATraits::InstructionT; |
61 | |
62 | // A UseT represents a data-edge from the defining instruction to the using |
63 | // instruction. |
64 | using UseT = typename SSATraits::UseT; |
65 | |
66 | // A BlockT is a sequence of InstructionT, and forms a node of the CFG. It |
67 | // has global methods predecessors() and successors() that return |
68 | // the list of incoming CFG edges and outgoing CFG edges |
69 | // respectively. |
70 | using BlockT = typename SSATraits::BlockT; |
71 | |
72 | // A FunctionT represents a CFG along with arguments and return values. It is |
73 | // the smallest complete unit of code in a Module. |
74 | using FunctionT = typename SSATraits::FunctionT; |
75 | |
76 | // A dominator tree provides the dominance relation between basic blocks in |
77 | // a given funciton. |
78 | using DominatorTreeT = DominatorTreeBase<BlockT, false>; |
79 | |
80 | GenericSSAContext() = default; |
81 | GenericSSAContext(const FunctionT *F) : F(F) {} |
82 | |
83 | const FunctionT *getFunction() const { return F; } |
84 | |
85 | static Intrinsic::ID getIntrinsicID(const InstructionT &I); |
86 | |
87 | static void appendBlockDefs(SmallVectorImpl<ValueRefT> &defs, BlockT &block); |
88 | static void appendBlockDefs(SmallVectorImpl<ConstValueRefT> &defs, |
89 | const BlockT &block); |
90 | |
91 | static void appendBlockTerms(SmallVectorImpl<InstructionT *> &terms, |
92 | BlockT &block); |
93 | static void appendBlockTerms(SmallVectorImpl<const InstructionT *> &terms, |
94 | const BlockT &block); |
95 | |
96 | static bool isConstantOrUndefValuePhi(const InstructionT &Instr); |
97 | const BlockT *getDefBlock(ConstValueRefT value) const; |
98 | |
99 | Printable print(const BlockT *block) const; |
100 | Printable printAsOperand(const BlockT *BB) const; |
101 | Printable print(const InstructionT *inst) const; |
102 | Printable print(ConstValueRefT value) const; |
103 | }; |
104 | } // namespace llvm |
105 | |
106 | #endif // LLVM_ADT_GENERICSSACONTEXT_H |
107 | |