1//===--- EvalEmitter.h - Instruction emitter for the VM ---------*- 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// Defines the instruction emitters.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_AST_INTERP_EVALEMITTER_H
14#define LLVM_CLANG_AST_INTERP_EVALEMITTER_H
15
16#include "EvaluationResult.h"
17#include "InterpState.h"
18#include "PrimType.h"
19#include "Source.h"
20#include "llvm/Support/Error.h"
21
22namespace clang {
23namespace interp {
24class Context;
25class Function;
26class InterpStack;
27class Program;
28enum Opcode : uint32_t;
29
30/// An emitter which evaluates opcodes as they are emitted.
31class EvalEmitter : public SourceMapper {
32public:
33 using LabelTy = uint32_t;
34 using AddrTy = uintptr_t;
35 using Local = Scope::Local;
36
37 EvaluationResult interpretExpr(const Expr *E,
38 bool ConvertResultToRValue = false);
39 EvaluationResult interpretDecl(const VarDecl *VD, bool CheckFullyInitialized);
40
41 InterpState &getState() { return S; }
42
43protected:
44 EvalEmitter(Context &Ctx, Program &P, State &Parent, InterpStack &Stk);
45
46 virtual ~EvalEmitter();
47
48 /// Define a label.
49 void emitLabel(LabelTy Label);
50 /// Create a label.
51 LabelTy getLabel();
52
53 /// Methods implemented by the compiler.
54 virtual bool visitExpr(const Expr *E) = 0;
55 virtual bool visitDecl(const VarDecl *VD) = 0;
56
57 /// Emits jumps.
58 bool jumpTrue(const LabelTy &Label);
59 bool jumpFalse(const LabelTy &Label);
60 bool jump(const LabelTy &Label);
61 bool fallthrough(const LabelTy &Label);
62
63 /// Callback for registering a local.
64 Local createLocal(Descriptor *D);
65
66 /// Returns the source location of the current opcode.
67 SourceInfo getSource(const Function *F, CodePtr PC) const override {
68 return (F && F->hasBody()) ? F->getSource(PC) : CurrentSource;
69 }
70
71 /// Parameter indices.
72 llvm::DenseMap<const ParmVarDecl *, ParamOffset> Params;
73 /// Lambda captures.
74 llvm::DenseMap<const ValueDecl *, ParamOffset> LambdaCaptures;
75 /// Offset of the This parameter in a lambda record.
76 ParamOffset LambdaThisCapture{.Offset: 0, .IsPtr: false};
77 /// Local descriptors.
78 llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors;
79
80private:
81 /// Current compilation context.
82 Context &Ctx;
83 /// Current program.
84 Program &P;
85 /// Callee evaluation state.
86 InterpState S;
87 /// Location to write the result to.
88 EvaluationResult EvalResult;
89 /// Whether the result should be converted to an RValue.
90 bool ConvertResultToRValue = false;
91 /// Whether we should check if the result has been fully
92 /// initialized.
93 bool CheckFullyInitialized = false;
94
95 /// Temporaries which require storage.
96 llvm::DenseMap<unsigned, std::unique_ptr<char[]>> Locals;
97
98 Block *getLocal(unsigned Index) const {
99 auto It = Locals.find(Index);
100 assert(It != Locals.end() && "Missing local variable");
101 return reinterpret_cast<Block *>(It->second.get());
102 }
103
104 // The emitter always tracks the current instruction and sets OpPC to a token
105 // value which is mapped to the location of the opcode being evaluated.
106 CodePtr OpPC;
107 /// Location of the current instruction.
108 SourceInfo CurrentSource;
109
110 /// Next label ID to generate - first label is 1.
111 LabelTy NextLabel = 1;
112 /// Label being executed - 0 is the entry label.
113 LabelTy CurrentLabel = 0;
114 /// Active block which should be executed.
115 LabelTy ActiveLabel = 0;
116
117 /// Since expressions can only jump forward, predicated execution is
118 /// used to deal with if-else statements.
119 bool isActive() const { return CurrentLabel == ActiveLabel; }
120
121protected:
122#define GET_EVAL_PROTO
123#include "Opcodes.inc"
124#undef GET_EVAL_PROTO
125};
126
127} // namespace interp
128} // namespace clang
129
130#endif
131

source code of clang/lib/AST/Interp/EvalEmitter.h