1 files changed, 61 insertions, 13 deletions

diff --git a/clang/lib/AST/Interp/Function.h b/clang/lib/AST/Interp/Function.h
index ac1dffea1160..5b2a77f1a12d 100644
--- a/clang/lib/AST/Interp/Function.h
+++ b/clang/lib/AST/Interp/Function.h
@@ -29,7 +29,7 @@ enum PrimType : uint32_t;
 /// Describes a scope block.
 ///
 /// The block gathers all the descriptors of the locals defined in this block.
-class Scope {
+class Scope final {
 public:
   /// Information about a local's storage.
   struct Local {
@@ -43,7 +43,7 @@ public:
 
   Scope(LocalVectorTy &&Descriptors) : Descriptors(std::move(Descriptors)) {}
 
-  llvm::iterator_range<LocalVectorTy::iterator> locals() {
+  llvm::iterator_range<LocalVectorTy::const_iterator> locals() const {
     return llvm::make_range(Descriptors.begin(), Descriptors.end());
   }
 
@@ -56,23 +56,42 @@ private:
 ///
 /// Contains links to the bytecode of the function, as well as metadata
 /// describing all arguments and stack-local variables.
-class Function {
+///
+/// # Calling Convention
+///
+/// When calling a function, all argument values must be on the stack.
+///
+/// If the function has a This pointer (i.e. hasThisPointer() returns true,
+/// the argument values need to be preceeded by a Pointer for the This object.
+///
+/// If the function uses Return Value Optimization, the arguments (and
+/// potentially the This pointer) need to be proceeded by a Pointer pointing
+/// to the location to construct the returned value.
+///
+/// After the function has been called, it will remove all arguments,
+/// including RVO and This pointer, from the stack.
+///
+class Function final {
 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
+  /// Returns the size of the argument stack.
   unsigned getArgSize() const { return ArgSize; }
 
   /// Returns a pointer to the start of the code.
-  CodePtr getCodeBegin() const;
+  CodePtr getCodeBegin() const { return Code.data(); }
   /// Returns a pointer to the end of the code.
-  CodePtr getCodeEnd() const;
+  CodePtr getCodeEnd() const { return Code.data() + Code.size(); }
 
   /// Returns the original FunctionDecl.
   const FunctionDecl *getDecl() const { return F; }
 
+  /// Returns the name of the function decl this code
+  /// was generated for.
+  const std::string getName() const { return F->getNameInfo().getAsString(); }
+
   /// Returns the location.
   SourceLocation getLoc() const { return Loc; }
 
@@ -80,21 +99,24 @@ public:
   ParamDescriptor getParamDescriptor(unsigned Offset) const;
 
   /// Checks if the first argument is a RVO pointer.
-  bool hasRVO() const { return ParamTypes.size() != Params.size(); }
+  bool hasRVO() const { return HasRVO; }
 
   /// Range over the scope blocks.
-  llvm::iterator_range<llvm::SmallVector<Scope, 2>::iterator> scopes() {
+  llvm::iterator_range<llvm::SmallVector<Scope, 2>::const_iterator>
+  scopes() const {
     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());
+  using arg_reverse_iterator =
+      SmallVectorImpl<PrimType>::const_reverse_iterator;
+  llvm::iterator_range<arg_reverse_iterator> args_reverse() const {
+    return llvm::reverse(ParamTypes);
   }
 
   /// Returns a specific scope.
   Scope &getScope(unsigned Idx) { return Scopes[Idx]; }
+  const Scope &getScope(unsigned Idx) const { return Scopes[Idx]; }
 
   /// Returns the source information at a given PC.
   SourceInfo getSource(CodePtr PC) const;
@@ -108,11 +130,22 @@ public:
   /// Checks if the function is a constructor.
   bool isConstructor() const { return isa<CXXConstructorDecl>(F); }
 
+  /// Checks if the function is fully done compiling.
+  bool isFullyCompiled() const { return IsFullyCompiled; }
+
+  bool hasThisPointer() const { return HasThisPointer; }
+
+  // Checks if the funtion already has a body attached.
+  bool hasBody() const { return HasBody; }
+
+  unsigned getNumParams() const { return ParamTypes.size(); }
+
 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);
+           llvm::DenseMap<unsigned, ParamDescriptor> &&Params,
+           bool HasThisPointer, bool HasRVO);
 
   /// Sets the code of a function.
   void setCode(unsigned NewFrameSize, std::vector<char> &&NewCode, SourceMap &&NewSrcMap,
@@ -122,8 +155,11 @@ private:
     SrcMap = std::move(NewSrcMap);
     Scopes = std::move(NewScopes);
     IsValid = true;
+    HasBody = true;
   }
 
+  void setIsFullyCompiled(bool FC) { IsFullyCompiled = FC; }
+
 private:
   friend class Program;
   friend class ByteCodeEmitter;
@@ -135,7 +171,7 @@ private:
   /// Declaration this function was compiled from.
   const FunctionDecl *F;
   /// Local area size: storage + metadata.
-  unsigned FrameSize;
+  unsigned FrameSize = 0;
   /// Size of the argument stack.
   unsigned ArgSize;
   /// Program code.
@@ -150,6 +186,18 @@ private:
   llvm::DenseMap<unsigned, ParamDescriptor> Params;
   /// Flag to indicate if the function is valid.
   bool IsValid = false;
+  /// Flag to indicate if the function is done being
+  /// compiled to bytecode.
+  bool IsFullyCompiled = false;
+  /// Flag indicating if this function takes the this pointer
+  /// as the first implicit argument
+  bool HasThisPointer = false;
+  /// Whether this function has Return Value Optimization, i.e.
+  /// the return value is constructed in the caller's stack frame.
+  /// This is done for functions that return non-primive values.
+  bool HasRVO = false;
+  /// If we've already compiled the function's body.
+  bool HasBody = false;
 
 public:
   /// Dumps the disassembled bytecode to \c llvm::errs().