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 Function *Func = P->getFunction(FD);
31 if (!Func) {
32 if (auto R = ByteCodeStmtGen<ByteCodeEmitter>(*this, *P).compileFunc(FD)) {
33 Func = *R;
34 } else {
35 handleAllErrors(R.takeError(), [&Parent](ByteCodeGenError &Err) {
36 Parent.FFDiag(Err.getLoc(), diag::err_experimental_clang_interp_failed);
37 });
38 return false;
39 }
40 }
41
42 if (!Func->isConstexpr())
43 return false;
44
45 APValue Dummy;
46 return Run(Parent, Func, Dummy);
47 }
48
evaluateAsRValue(State & Parent,const Expr * E,APValue & Result)49 bool Context::evaluateAsRValue(State &Parent, const Expr *E, APValue &Result) {
50 ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);
51 return Check(Parent, C.interpretExpr(E));
52 }
53
evaluateAsInitializer(State & Parent,const VarDecl * VD,APValue & Result)54 bool Context::evaluateAsInitializer(State &Parent, const VarDecl *VD,
55 APValue &Result) {
56 ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);
57 return Check(Parent, C.interpretDecl(VD));
58 }
59
getLangOpts() const60 const LangOptions &Context::getLangOpts() const { return Ctx.getLangOpts(); }
61
classify(QualType T)62 llvm::Optional<PrimType> Context::classify(QualType T) {
63 if (T->isReferenceType() || T->isPointerType()) {
64 return PT_Ptr;
65 }
66
67 if (T->isBooleanType())
68 return PT_Bool;
69
70 if (T->isSignedIntegerOrEnumerationType()) {
71 switch (Ctx.getIntWidth(T)) {
72 case 64:
73 return PT_Sint64;
74 case 32:
75 return PT_Sint32;
76 case 16:
77 return PT_Sint16;
78 case 8:
79 return PT_Sint8;
80 default:
81 return {};
82 }
83 }
84
85 if (T->isUnsignedIntegerOrEnumerationType()) {
86 switch (Ctx.getIntWidth(T)) {
87 case 64:
88 return PT_Uint64;
89 case 32:
90 return PT_Uint32;
91 case 16:
92 return PT_Uint16;
93 case 8:
94 return PT_Uint8;
95 default:
96 return {};
97 }
98 }
99
100 if (T->isNullPtrType())
101 return PT_Ptr;
102
103 if (auto *AT = dyn_cast<AtomicType>(T))
104 return classify(AT->getValueType());
105
106 return {};
107 }
108
getCharBit() const109 unsigned Context::getCharBit() const {
110 return Ctx.getTargetInfo().getCharWidth();
111 }
112
Run(State & Parent,Function * Func,APValue & Result)113 bool Context::Run(State &Parent, Function *Func, APValue &Result) {
114 InterpState State(Parent, *P, Stk, *this);
115 State.Current = new InterpFrame(State, Func, nullptr, {}, {});
116 if (Interpret(State, Result))
117 return true;
118 Stk.clear();
119 return false;
120 }
121
Check(State & Parent,llvm::Expected<bool> && Flag)122 bool Context::Check(State &Parent, llvm::Expected<bool> &&Flag) {
123 if (Flag)
124 return *Flag;
125 handleAllErrors(Flag.takeError(), [&Parent](ByteCodeGenError &Err) {
126 Parent.FFDiag(Err.getLoc(), diag::err_experimental_clang_interp_failed);
127 });
128 return false;
129 }
130