1 //===--- Context.cpp - Context for the constexpr 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 #include "Context.h"
10 #include "ByteCodeEmitter.h"
11 #include "ByteCodeExprGen.h"
12 #include "ByteCodeStmtGen.h"
13 #include "EvalEmitter.h"
14 #include "Interp.h"
15 #include "InterpFrame.h"
16 #include "InterpStack.h"
17 #include "PrimType.h"
18 #include "Program.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/Basic/TargetInfo.h"
21
22 using namespace clang;
23 using namespace clang::interp;
24
Context(ASTContext & Ctx)25 Context::Context(ASTContext &Ctx) : Ctx(Ctx), P(new Program(*this)) {}
26
~Context()27 Context::~Context() {}
28
isPotentialConstantExpr(State & Parent,const FunctionDecl * FD)29 bool Context::isPotentialConstantExpr(State &Parent, const FunctionDecl *FD) {
30 assert(Stk.empty());
31 Function *Func = P->getFunction(FD);
32 if (!Func || !Func->hasBody()) {
33 if (auto R = ByteCodeStmtGen<ByteCodeEmitter>(*this, *P).compileFunc(FD)) {
34 Func = *R;
35 } else {
36 handleAllErrors(R.takeError(), [&Parent](ByteCodeGenError &Err) {
37 Parent.FFDiag(Err.getRange().getBegin(),
38 diag::err_experimental_clang_interp_failed)
39 << Err.getRange();
40 });
41 return false;
42 }
43 }
44
45 return Func->isConstexpr();
46 }
47
evaluateAsRValue(State & Parent,const Expr * E,APValue & Result)48 bool Context::evaluateAsRValue(State &Parent, const Expr *E, APValue &Result) {
49 assert(Stk.empty());
50 ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);
51 if (Check(Parent, C.interpretExpr(E))) {
52 assert(Stk.empty());
53 return true;
54 }
55
56 Stk.clear();
57 return false;
58 }
59
evaluateAsInitializer(State & Parent,const VarDecl * VD,APValue & Result)60 bool Context::evaluateAsInitializer(State &Parent, const VarDecl *VD,
61 APValue &Result) {
62 assert(Stk.empty());
63 ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);
64 if (Check(Parent, C.interpretDecl(VD))) {
65 assert(Stk.empty());
66 return true;
67 }
68
69 Stk.clear();
70 return false;
71 }
72
getLangOpts() const73 const LangOptions &Context::getLangOpts() const { return Ctx.getLangOpts(); }
74
classify(QualType T) const75 std::optional<PrimType> Context::classify(QualType T) const {
76 if (T->isReferenceType() || T->isPointerType()) {
77 return PT_Ptr;
78 }
79
80 if (T->isBooleanType())
81 return PT_Bool;
82
83 if (T->isSignedIntegerOrEnumerationType()) {
84 switch (Ctx.getIntWidth(T)) {
85 case 64:
86 return PT_Sint64;
87 case 32:
88 return PT_Sint32;
89 case 16:
90 return PT_Sint16;
91 case 8:
92 return PT_Sint8;
93 default:
94 return {};
95 }
96 }
97
98 if (T->isUnsignedIntegerOrEnumerationType()) {
99 switch (Ctx.getIntWidth(T)) {
100 case 64:
101 return PT_Uint64;
102 case 32:
103 return PT_Uint32;
104 case 16:
105 return PT_Uint16;
106 case 8:
107 return PT_Uint8;
108 default:
109 return {};
110 }
111 }
112
113 if (T->isNullPtrType())
114 return PT_Ptr;
115
116 if (auto *AT = dyn_cast<AtomicType>(T))
117 return classify(AT->getValueType());
118
119 return {};
120 }
121
getCharBit() const122 unsigned Context::getCharBit() const {
123 return Ctx.getTargetInfo().getCharWidth();
124 }
125
Run(State & Parent,Function * Func,APValue & Result)126 bool Context::Run(State &Parent, Function *Func, APValue &Result) {
127 InterpState State(Parent, *P, Stk, *this);
128 State.Current = new InterpFrame(State, Func, /*Caller=*/nullptr, {});
129 if (Interpret(State, Result))
130 return true;
131 Stk.clear();
132 return false;
133 }
134
Check(State & Parent,llvm::Expected<bool> && Flag)135 bool Context::Check(State &Parent, llvm::Expected<bool> &&Flag) {
136 if (Flag)
137 return *Flag;
138 handleAllErrors(Flag.takeError(), [&Parent](ByteCodeGenError &Err) {
139 Parent.FFDiag(Err.getRange().getBegin(),
140 diag::err_experimental_clang_interp_failed)
141 << Err.getRange();
142 });
143 return false;
144 }
145