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+//===--- InterpFrame.h - Call Frame implementation 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 class storing information about stack frames in the interpreter.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_INTERP_INTERPFRAME_H
+#define LLVM_CLANG_AST_INTERP_INTERPFRAME_H
+
+#include "Frame.h"
+#include "Pointer.h"
+#include "Program.h"
+#include "State.h"
+#include <cstdint>
+#include <vector>
+
+namespace clang {
+namespace interp {
+class Function;
+class InterpState;
+
+/// Frame storing local variables.
+class InterpFrame final : public Frame {
+public:
+ /// The frame of the previous function.
+ InterpFrame *Caller;
+
+ /// Creates a new frame for a method call.
+ InterpFrame(InterpState &S, Function *Func, InterpFrame *Caller,
+ CodePtr RetPC, Pointer &&This);
+
+ /// Destroys the frame, killing all live pointers to stack slots.
+ ~InterpFrame();
+
+ /// Invokes the destructors for a scope.
+ void destroy(unsigned Idx);
+
+ /// Pops the arguments off the stack.
+ void popArgs();
+
+ /// Describes the frame with arguments for diagnostic purposes.
+ void describe(llvm::raw_ostream &OS);
+
+ /// Returns the parent frame object.
+ Frame *getCaller() const;
+
+ /// Returns the location of the call to the frame.
+ SourceLocation getCallLocation() const;
+
+ /// Returns the caller.
+ const FunctionDecl *getCallee() const;
+
+ /// Returns the current function.
+ Function *getFunction() const { return Func; }
+
+ /// Returns the offset on the stack at which the frame starts.
+ size_t getFrameOffset() const { return FrameOffset; }
+
+ /// Returns the value of a local variable.
+ template <typename T> const T &getLocal(unsigned Offset) {
+ return localRef<T>(Offset);
+ }
+
+ /// Mutates a local variable.
+ template <typename T> void setLocal(unsigned Offset, const T &Value) {
+ localRef<T>(Offset) = Value;
+ }
+
+ /// Returns a pointer to a local variables.
+ Pointer getLocalPointer(unsigned Offset);
+
+ /// Returns the value of an argument.
+ template <typename T> const T &getParam(unsigned Offset) {
+ auto Pt = Params.find(Offset);
+ if (Pt == Params.end()) {
+ return stackRef<T>(Offset);
+ } else {
+ return Pointer(reinterpret_cast<Block *>(Pt->second.get())).deref<T>();
+ }
+ }
+
+ /// Mutates a local copy of a parameter.
+ template <typename T> void setParam(unsigned Offset, const T &Value) {
+ getParamPointer(Offset).deref<T>() = Value;
+ }
+
+ /// Returns a pointer to an argument - lazily creates a block.
+ Pointer getParamPointer(unsigned Offset);
+
+ /// Returns the 'this' pointer.
+ const Pointer &getThis() const { return This; }
+
+ /// Checks if the frame is a root frame - return should quit the interpreter.
+ bool isRoot() const { return !Func; }
+
+ /// Returns the PC of the frame's code start.
+ CodePtr getPC() const { return Func->getCodeBegin(); }
+
+ /// Returns the return address of the frame.
+ CodePtr getRetPC() const { return RetPC; }
+
+ /// Map a location to a source.
+ virtual SourceInfo getSource(CodePtr PC) const;
+ const Expr *getExpr(CodePtr PC) const;
+ SourceLocation getLocation(CodePtr PC) const;
+
+private:
+ /// Returns an original argument from the stack.
+ template <typename T> const T &stackRef(unsigned Offset) {
+ return *reinterpret_cast<const T *>(Args - ArgSize + Offset);
+ }
+
+ /// Returns an offset to a local.
+ template <typename T> T &localRef(unsigned Offset) {
+ return *reinterpret_cast<T *>(Locals.get() + Offset);
+ }
+
+ /// Returns a pointer to a local's block.
+ void *localBlock(unsigned Offset) {
+ return Locals.get() + Offset - sizeof(Block);
+ }
+
+private:
+ /// Reference to the interpreter state.
+ InterpState &S;
+ /// Reference to the function being executed.
+ Function *Func;
+ /// Current object pointer for methods.
+ Pointer This;
+ /// Return address.
+ CodePtr RetPC;
+ /// The size of all the arguments.
+ const unsigned ArgSize;
+ /// Pointer to the arguments in the callee's frame.
+ char *Args = nullptr;
+ /// Fixed, initial storage for known local variables.
+ std::unique_ptr<char[]> Locals;
+ /// Offset on the stack at entry.
+ const size_t FrameOffset;
+ /// Mapping from arg offsets to their argument blocks.
+ llvm::DenseMap<unsigned, std::unique_ptr<char[]>> Params;
+};
+
+} // namespace interp
+} // namespace clang
+
+#endif