clang 17.0.0git
EvalEmitter.h
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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 "ByteCodeGenError.h"
17#include "Context.h"
18#include "InterpStack.h"
19#include "InterpState.h"
20#include "PrimType.h"
21#include "Program.h"
22#include "Source.h"
23#include "llvm/Support/Error.h"
24
25namespace clang {
26namespace interp {
27class Context;
28class Function;
29class InterpState;
30class Program;
31class SourceInfo;
32enum Opcode : uint32_t;
33
34/// An emitter which evaluates opcodes as they are emitted.
35class EvalEmitter : public SourceMapper {
36public:
37 using LabelTy = uint32_t;
40
43
44protected:
46 APValue &Result);
47
48 virtual ~EvalEmitter() {}
49
50 /// Define a label.
52 /// Create a label.
54
55 /// Methods implemented by the compiler.
56 virtual bool visitExpr(const Expr *E) = 0;
57 virtual bool visitDecl(const VarDecl *VD) = 0;
58
59 bool bail(const Stmt *S) { return bail(S->getBeginLoc()); }
60 bool bail(const Decl *D) { return bail(D->getBeginLoc()); }
61 bool bail(const SourceLocation &Loc);
62
63 /// Emits jumps.
64 bool jumpTrue(const LabelTy &Label);
65 bool jumpFalse(const LabelTy &Label);
66 bool jump(const LabelTy &Label);
67 bool fallthrough(const LabelTy &Label);
68
69 /// Callback for registering a local.
71
72 /// Returns the source location of the current opcode.
73 SourceInfo getSource(const Function *F, CodePtr PC) const override {
74 return (F && F->hasBody()) ? F->getSource(PC) : CurrentSource;
75 }
76
77 /// Parameter indices.
78 llvm::DenseMap<const ParmVarDecl *, unsigned> Params;
79 /// Local descriptors.
81
82private:
83 /// Current compilation context.
84 Context &Ctx;
85 /// Current program.
86 Program &P;
87 /// Callee evaluation state.
89 /// Location to write the result to.
90 APValue &Result;
91
92 /// Temporaries which require storage.
93 llvm::DenseMap<unsigned, std::unique_ptr<char[]>> Locals;
94
95 Block *getLocal(unsigned Index) const {
96 auto It = Locals.find(Index);
97 assert(It != Locals.end() && "Missing local variable");
98 return reinterpret_cast<Block *>(It->second.get());
99 }
100
101 // The emitter always tracks the current instruction and sets OpPC to a token
102 // value which is mapped to the location of the opcode being evaluated.
103 CodePtr OpPC;
104 /// Location of a failure.
105 std::optional<SourceLocation> BailLocation;
106 /// Location of the current instruction.
107 SourceInfo CurrentSource;
108
109 /// Next label ID to generate - first label is 1.
110 LabelTy NextLabel = 1;
111 /// Label being executed - 0 is the entry label.
112 LabelTy CurrentLabel = 0;
113 /// Active block which should be executed.
114 LabelTy ActiveLabel = 0;
115
116 /// Since expressions can only jump forward, predicated execution is
117 /// used to deal with if-else statements.
118 bool isActive() const { return CurrentLabel == ActiveLabel; }
119
120protected:
121#define GET_EVAL_PROTO
122#include "Opcodes.inc"
123#undef GET_EVAL_PROTO
124};
125
126} // namespace interp
127} // namespace clang
128
129#endif
NodeId Parent
Definition: ASTDiff.cpp:191
std::string Label
APValue - This class implements a discriminated union of [uninitialized] [APSInt] [APFloat],...
Definition: APValue.h:122
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:83
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: DeclBase.h:424
This represents one expression.
Definition: Expr.h:110
Encodes a location in the source.
Stmt - This represents one statement.
Definition: Stmt.h:72
Represents a variable declaration or definition.
Definition: Decl.h:913
A memory block, either on the stack or in the heap.
Definition: InterpBlock.h:49
Pointer into the code segment.
Definition: Source.h:26
Holds all information required to evaluate constexpr code in a module.
Definition: Context.h:35
An emitter which evaluates opcodes as they are emitted.
Definition: EvalEmitter.h:35
bool jump(const LabelTy &Label)
Definition: EvalEmitter.cpp:96
llvm::DenseMap< const ParmVarDecl *, unsigned > Params
Parameter indices.
Definition: EvalEmitter.h:78
virtual bool visitExpr(const Expr *E)=0
Methods implemented by the compiler.
bool jumpFalse(const LabelTy &Label)
Definition: EvalEmitter.cpp:88
Local createLocal(Descriptor *D)
Callback for registering a local.
Definition: EvalEmitter.cpp:52
bool bail(const Stmt *S)
Definition: EvalEmitter.h:59
void emitLabel(LabelTy Label)
Define a label.
Definition: EvalEmitter.cpp:46
bool fallthrough(const LabelTy &Label)
LabelTy getLabel()
Create a label.
Definition: EvalEmitter.cpp:50
llvm::Expected< bool > interpretDecl(const VarDecl *VD)
Definition: EvalEmitter.cpp:38
bool bail(const Decl *D)
Definition: EvalEmitter.h:60
llvm::Expected< bool > interpretExpr(const Expr *E)
Definition: EvalEmitter.cpp:30
SourceInfo getSource(const Function *F, CodePtr PC) const override
Returns the source location of the current opcode.
Definition: EvalEmitter.h:73
llvm::SmallVector< SmallVector< Local, 8 >, 2 > Descriptors
Local descriptors.
Definition: EvalEmitter.h:80
virtual bool visitDecl(const VarDecl *VD)=0
bool jumpTrue(const LabelTy &Label)
Emits jumps.
Definition: EvalEmitter.cpp:80
Bytecode function.
Definition: Function.h:74
bool hasBody() const
Definition: Function.h:146
SourceInfo getSource(CodePtr PC) const
Returns the source information at a given PC.
Definition: Function.cpp:32
Stack frame storing temporaries and parameters.
Definition: InterpStack.h:25
Interpreter context.
Definition: InterpState.h:34
The program contains and links the bytecode for all functions.
Definition: Program.h:40
Describes the statement/declaration an opcode was generated from.
Definition: Source.h:70
Interface for classes which map locations to sources.
Definition: Source.h:91
Interface for the VM to interact with the AST walker's context.
Definition: State.h:55
__UINTPTR_TYPE__ uintptr_t
An unsigned integer type with the property that any valid pointer to void can be converted to this ty...
Describes a memory block created by an allocation site.
Definition: Descriptor.h:76
Information about a local's storage.
Definition: Function.h:35