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 _FunctionT> class GenericSSAContext {
25 public:
26   // Specializations should provide the following types that are similar to how
27   // LLVM IR is structured:
28 
29   // The smallest unit of the IR is a ValueT. The SSA context uses a ValueRefT,
30   // which is a pointer to a ValueT, since Machine IR does not have the
31   // equivalent of a ValueT.
32   //
33   // using ValueRefT = ...
34 
35   // An InstT is a subclass of ValueT that itself defines one or more ValueT
36   // objects.
37   //
38   // using InstT = ... must be a subclass of Value
39 
40   // A BlockT is a sequence of InstT, and forms a node of the CFG. It
41   // has global methods predecessors() and successors() that return
42   // the list of incoming CFG edges and outgoing CFG edges
43   // respectively.
44   //
45   // using BlockT = ...
46 
47   // A FunctionT represents a CFG along with arguments and return values. It is
48   // the smallest complete unit of code in a Module.
49   //
50   // The compiler produces an error here if this class is implicitly
51   // specialized due to an instantiation. An explicit specialization
52   // of this template needs to be added before the instantiation point
53   // indicated by the compiler.
54   using FunctionT = typename _FunctionT::invalidTemplateInstanceError;
55 
56   // Every FunctionT has a unique BlockT marked as its entry.
57   //
58   // static BlockT* getEntryBlock(FunctionT &F);
59 
60   // Initialize the SSA context with information about the FunctionT being
61   // processed.
62   //
63   // void setFunction(FunctionT &function);
64   // FunctionT* getFunction() const;
65 
66   // Methods to print various objects.
67   //
68   // Printable print(BlockT *block) const;
69   // Printable print(InstructionT *inst) const;
70   // Printable print(ValueRefT value) const;
71 };
72 } // namespace llvm
73 
74 #endif // LLVM_ADT_GENERICSSACONTEXT_H
75