forked from OSchip/llvm-project
101 lines
2.9 KiB
C++
101 lines
2.9 KiB
C++
//===--- Context.h - Context for the constexpr VM ---------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Defines the constexpr execution context.
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//
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// The execution context manages cached bytecode and the global context.
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// It invokes the compiler and interpreter, propagating errors.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_AST_INTERP_CONTEXT_H
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#define LLVM_CLANG_AST_INTERP_CONTEXT_H
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#include "Context.h"
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#include "InterpStack.h"
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#include "clang/AST/APValue.h"
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#include "llvm/ADT/PointerIntPair.h"
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namespace clang {
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class ASTContext;
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class LangOptions;
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class Stmt;
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class FunctionDecl;
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class VarDecl;
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namespace interp {
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class Function;
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class Program;
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class State;
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enum PrimType : unsigned;
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/// Wrapper around interpreter termination results.
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enum class InterpResult {
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/// Interpreter successfully computed a value.
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Success,
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/// Interpreter encountered an error and quit.
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Fail,
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/// Interpreter encountered an unimplemented feature, AST fallback.
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Bail,
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};
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/// Holds all information required to evaluate constexpr code in a module.
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class Context {
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public:
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/// Initialises the constexpr VM.
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Context(ASTContext &Ctx);
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/// Cleans up the constexpr VM.
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~Context();
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/// Checks if a function is a potential constant expression.
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InterpResult isPotentialConstantExpr(State &Parent,
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const FunctionDecl *FnDecl);
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/// Evaluates a toplevel expression as an rvalue.
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InterpResult evaluateAsRValue(State &Parent, const Expr *E, APValue &Result);
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/// Evaluates a toplevel initializer.
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InterpResult evaluateAsInitializer(State &Parent, const VarDecl *VD,
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APValue &Result);
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/// Returns the AST context.
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ASTContext &getASTContext() const { return Ctx; }
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/// Returns the language options.
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const LangOptions &getLangOpts() const;
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/// Returns the interpreter stack.
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InterpStack &getStack() { return Stk; }
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/// Returns CHAR_BIT.
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unsigned getCharBit() const;
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/// Classifies an expression.
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llvm::Optional<PrimType> classify(QualType T);
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private:
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/// Runs a function.
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InterpResult Run(State &Parent, Function *Func, APValue &Result);
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/// Checks a result fromt the interpreter.
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InterpResult Check(State &Parent, llvm::Expected<bool> &&R);
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private:
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/// Current compilation context.
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ASTContext &Ctx;
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/// Flag to indicate if the use of the interpreter is mandatory.
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bool ForceInterp;
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/// Interpreter stack, shared across invocations.
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InterpStack Stk;
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/// Constexpr program.
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std::unique_ptr<Program> P;
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};
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} // namespace interp
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} // namespace clang
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#endif
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