1 //===--- Context.h - 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 // Defines the constexpr execution context. 10 // 11 // The execution context manages cached bytecode and the global context. 12 // It invokes the compiler and interpreter, propagating errors. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_CLANG_AST_INTERP_CONTEXT_H 17 #define LLVM_CLANG_AST_INTERP_CONTEXT_H 18 19 #include "Context.h" 20 #include "InterpStack.h" 21 #include "clang/AST/APValue.h" 22 #include "llvm/ADT/PointerIntPair.h" 23 24 namespace clang { 25 class ASTContext; 26 class LangOptions; 27 class Stmt; 28 class FunctionDecl; 29 class VarDecl; 30 31 namespace interp { 32 class Function; 33 class Program; 34 class State; 35 enum PrimType : unsigned; 36 37 /// Holds all information required to evaluate constexpr code in a module. 38 class Context { 39 public: 40 /// Initialises the constexpr VM. 41 Context(ASTContext &Ctx); 42 43 /// Cleans up the constexpr VM. 44 ~Context(); 45 46 /// Checks if a function is a potential constant expression. 47 bool isPotentialConstantExpr(State &Parent, const FunctionDecl *FnDecl); 48 49 /// Evaluates a toplevel expression as an rvalue. 50 bool evaluateAsRValue(State &Parent, const Expr *E, APValue &Result); 51 52 /// Evaluates a toplevel initializer. 53 bool evaluateAsInitializer(State &Parent, const VarDecl *VD, APValue &Result); 54 55 /// Returns the AST context. 56 ASTContext &getASTContext() const { return Ctx; } 57 /// Returns the language options. 58 const LangOptions &getLangOpts() const; 59 /// Returns the interpreter stack. 60 InterpStack &getStack() { return Stk; } 61 /// Returns CHAR_BIT. 62 unsigned getCharBit() const; 63 64 /// Classifies an expression. 65 llvm::Optional<PrimType> classify(QualType T); 66 67 private: 68 /// Runs a function. 69 bool Run(State &Parent, Function *Func, APValue &Result); 70 71 /// Checks a result fromt the interpreter. 72 bool Check(State &Parent, llvm::Expected<bool> &&R); 73 74 private: 75 /// Current compilation context. 76 ASTContext &Ctx; 77 /// Interpreter stack, shared across invocations. 78 InterpStack Stk; 79 /// Constexpr program. 80 std::unique_ptr<Program> P; 81 }; 82 83 } // namespace interp 84 } // namespace clang 85 86 #endif 87