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+//===--- Function.h - Bytecode function for the VM --------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines the Function class which holds all bytecode function-specific data.
+//
+// The scope class which describes local variables is also defined here.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_INTERP_FUNCTION_H
+#define LLVM_CLANG_AST_INTERP_FUNCTION_H
+
+#include "Pointer.h"
+#include "Source.h"
+#include "clang/AST/Decl.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace clang {
+namespace interp {
+class Program;
+class ByteCodeEmitter;
+enum PrimType : uint32_t;
+
+/// Describes a scope block.
+///
+/// The block gathers all the descriptors of the locals defined in this block.
+class Scope {
+public:
+ /// Information about a local's storage.
+ struct Local {
+ /// Offset of the local in frame.
+ unsigned Offset;
+ /// Descriptor of the local.
+ Descriptor *Desc;
+ };
+
+ using LocalVectorTy = llvm::SmallVector<Local, 8>;
+
+ Scope(LocalVectorTy &&Descriptors) : Descriptors(std::move(Descriptors)) {}
+
+ llvm::iterator_range<LocalVectorTy::iterator> locals() {
+ return llvm::make_range(Descriptors.begin(), Descriptors.end());
+ }
+
+private:
+ /// Object descriptors in this block.
+ LocalVectorTy Descriptors;
+};
+
+/// Bytecode function.
+///
+/// Contains links to the bytecode of the function, as well as metadata
+/// describing all arguments and stack-local variables.
+class Function {
+public:
+ using ParamDescriptor = std::pair<PrimType, Descriptor *>;
+
+ /// Returns the size of the function's local stack.
+ unsigned getFrameSize() const { return FrameSize; }
+ /// Returns the size of the argument stackx
+ unsigned getArgSize() const { return ArgSize; }
+
+ /// Returns a pointer to the start of the code.
+ CodePtr getCodeBegin() const;
+ /// Returns a pointer to the end of the code.
+ CodePtr getCodeEnd() const;
+
+ /// Returns the original FunctionDecl.
+ const FunctionDecl *getDecl() const { return F; }
+
+ /// Returns the lcoation.
+ SourceLocation getLoc() const { return Loc; }
+
+ /// Returns a parameter descriptor.
+ ParamDescriptor getParamDescriptor(unsigned Offset) const;
+
+ /// Checks if the first argument is a RVO pointer.
+ bool hasRVO() const { return ParamTypes.size() != Params.size(); }
+
+ /// Range over the scope blocks.
+ llvm::iterator_range<llvm::SmallVector<Scope, 2>::iterator> scopes() {
+ return llvm::make_range(Scopes.begin(), Scopes.end());
+ }
+
+ /// Range over argument types.
+ using arg_reverse_iterator = SmallVectorImpl<PrimType>::reverse_iterator;
+ llvm::iterator_range<arg_reverse_iterator> args_reverse() {
+ return llvm::make_range(ParamTypes.rbegin(), ParamTypes.rend());
+ }
+
+ /// Returns a specific scope.
+ Scope &getScope(unsigned Idx) { return Scopes[Idx]; }
+
+ /// Returns the source information at a given PC.
+ SourceInfo getSource(CodePtr PC) const;
+
+ /// Checks if the function is valid to call in constexpr.
+ bool isConstexpr() const { return IsValid; }
+
+ /// Checks if the function is virtual.
+ bool isVirtual() const;
+
+ /// Checks if the function is a constructor.
+ bool isConstructor() const { return isa<CXXConstructorDecl>(F); }
+
+private:
+ /// Construct a function representing an actual function.
+ Function(Program &P, const FunctionDecl *F, unsigned ArgSize,
+ llvm::SmallVector<PrimType, 8> &&ParamTypes,
+ llvm::DenseMap<unsigned, ParamDescriptor> &&Params);
+
+ /// Sets the code of a function.
+ void setCode(unsigned NewFrameSize, std::vector<char> &&NewCode, SourceMap &&NewSrcMap,
+ llvm::SmallVector<Scope, 2> &&NewScopes) {
+ FrameSize = NewFrameSize;
+ Code = std::move(NewCode);
+ SrcMap = std::move(NewSrcMap);
+ Scopes = std::move(NewScopes);
+ IsValid = true;
+ }
+
+private:
+ friend class Program;
+ friend class ByteCodeEmitter;
+
+ /// Program reference.
+ Program &P;
+ /// Location of the executed code.
+ SourceLocation Loc;
+ /// Declaration this function was compiled from.
+ const FunctionDecl *F;
+ /// Local area size: storage + metadata.
+ unsigned FrameSize;
+ /// Size of the argument stack.
+ unsigned ArgSize;
+ /// Program code.
+ std::vector<char> Code;
+ /// Opcode-to-expression mapping.
+ SourceMap SrcMap;
+ /// List of block descriptors.
+ llvm::SmallVector<Scope, 2> Scopes;
+ /// List of argument types.
+ llvm::SmallVector<PrimType, 8> ParamTypes;
+ /// Map from byte offset to parameter descriptor.
+ llvm::DenseMap<unsigned, ParamDescriptor> Params;
+ /// Flag to indicate if the function is valid.
+ bool IsValid = false;
+
+public:
+ /// Dumps the disassembled bytecode to \c llvm::errs().
+ void dump() const;
+ void dump(llvm::raw_ostream &OS) const;
+};
+
+} // namespace interp
+} // namespace clang
+
+#endif