1//===------ EvaluationResult.h - Result class 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#ifndef LLVM_CLANG_AST_INTERP_EVALUATION_RESULT_H
10#define LLVM_CLANG_AST_INTERP_EVALUATION_RESULT_H
11
12#include "clang/AST/APValue.h"
13#include "clang/AST/Decl.h"
14#include "clang/AST/Expr.h"
15
16namespace clang {
17namespace interp {
18class EvalEmitter;
19class Context;
20class Pointer;
21class SourceInfo;
22class InterpState;
23
24/// Defines the result of an evaluation.
25///
26/// The Kind defined if the evaluation was invalid, valid (but empty, e.g. for
27/// void expressions) or if we have a valid evaluation result.
28///
29/// We use this class to inspect and diagnose the result, as well as
30/// convert it to the requested form.
31class EvaluationResult final {
32public:
33 enum ResultKind {
34 Empty, // Initial state.
35 Invalid, // Result is invalid.
36 Valid, // Result is valid and empty.
37 };
38
39 using DeclTy = llvm::PointerUnion<const Decl *, const Expr *>;
40
41private:
42#ifndef NDEBUG
43 const Context *Ctx = nullptr;
44#endif
45 APValue Value;
46 ResultKind Kind = Empty;
47 DeclTy Source = nullptr;
48
49 void setSource(DeclTy D) { Source = D; }
50
51 void takeValue(APValue &&V) {
52 assert(empty());
53 Value = std::move(V);
54 }
55 void setInvalid() {
56 // We are NOT asserting empty() here, since setting it to invalid
57 // is allowed even if there is already a result.
58 Kind = Invalid;
59 }
60 void setValid() {
61 assert(empty());
62 Kind = Valid;
63 }
64
65public:
66#ifndef NDEBUG
67 EvaluationResult(const Context *Ctx) : Ctx(Ctx) {}
68#else
69 EvaluationResult(const Context *Ctx) {}
70#endif
71
72 bool empty() const { return Kind == Empty; }
73 bool isInvalid() const { return Kind == Invalid; }
74
75 /// Returns an APValue for the evaluation result.
76 APValue toAPValue() const {
77 assert(!empty());
78 assert(!isInvalid());
79 return Value;
80 }
81
82 APValue stealAPValue() { return std::move(Value); }
83
84 /// Check that all subobjects of the given pointer have been initialized.
85 bool checkFullyInitialized(InterpState &S, const Pointer &Ptr) const;
86 /// Check that none of the blocks the given pointer (transitively) points
87 /// to are dynamically allocated.
88 bool checkReturnValue(InterpState &S, const Context &Ctx, const Pointer &Ptr,
89 const SourceInfo &Info);
90
91 QualType getSourceType() const {
92 if (const auto *D =
93 dyn_cast_if_present<ValueDecl>(Val: Source.dyn_cast<const Decl *>()))
94 return D->getType();
95 if (const auto *E = Source.dyn_cast<const Expr *>())
96 return E->getType();
97 return QualType();
98 }
99
100 /// Dump to stderr.
101 void dump() const;
102
103 friend class EvalEmitter;
104 friend class InterpState;
105};
106
107} // namespace interp
108} // namespace clang
109
110#endif
111