1 files changed, 153 insertions, 0 deletions
diff --git a/clang/lib/AST/Interp/InterpFrame.h b/clang/lib/AST/Interp/InterpFrame.h
new file mode 100644
index 000000000000..b8391b0bcf92
--- /dev/null
+++ b/clang/lib/AST/Interp/InterpFrame.h
@@ -0,0 +1,153 @@
+//===--- 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