Merge change list off bleeding_edge into toiger branch.

src/macro-assembler-ia32.h

Index: src/macro-assembler-ia32.h
===================================================================
--- src/macro-assembler-ia32.h	(revision 668)
+++ src/macro-assembler-ia32.h	(working copy)
@@ -33,7 +33,7 @@
 namespace v8 { namespace internal {
 
 
-// Helper type to make boolean flag easier to read at call-site.
+// Helper types to make flags easier to read at call sites.
 enum InvokeFlag {
   CALL_FUNCTION,
   JUMP_FUNCTION
@@ -52,6 +52,306 @@
 };
 
 
+// -------------------------------------------------------------------------
+// Virtual frames
+//
+// The virtual frame is an abstraction of the physical stack frame.  It
+// encapsulates the parameters, frame-allocated locals, and the expression
+// stack.  It supports push/pop operations on the expression stack, as well
+// as random access to the expression stack elements, locals, and
+// parameters.
+
+class VirtualFrame : public Malloced {
+ public:
+  // Construct a virtual frame with the given code generator used to
+  // generate code.
+  explicit VirtualFrame(CodeGenerator* cgen);
+
+  // Construct a virtual frame that is a clone of an existing one, initially
+  // with an identical state.
+  explicit VirtualFrame(VirtualFrame* original);
+
+  // The height of the virtual expression stack.  Always non-negative.
+  int height() const { return height_; }
+
+  // Forget elements from the top of the expression stack.  This is
+  // used when the stack pointer is manually lowered to pop values
+  // left by statements (eg, for...in, try...finally) that have been
+  // escaped from.
+  void Forget(int count);
+
+  // Make this virtual frame have a state identical to an expected virtual
+  // frame.  As a side effect, code may be emitted to make this frame match
+  // the expected one.
+  void MergeTo(VirtualFrame* expected);
+
+  // Emit code for the physical JS entry and exit frame sequences.  After
+  // calling Enter, the virtual frame is ready for use; and after calling
+  // Exit it should not be used.  Note that Enter does not allocate space in
+  // the physical frame for storing frame-allocated locals.
+  void Enter();
+  void Exit();
+
+  // Allocate and initialize the frame-allocated locals.  The number of
+  // locals is known from the frame's code generator's state (specifically
+  // its scope).  As a side effect, code may be emitted.
+  void AllocateLocals();
+
+  // The current top of the expression stack as an assembly operand.
+  Operand Top() const { return Operand(esp, 0); }
+
+  // An element of the expression stack as an assembly operand.
+  Operand Element(int index) const {
+    return Operand(esp, index * kPointerSize);
+  }
+
+  // A frame-allocated local as an assembly operand.
+  Operand Local(int index) const {
+    ASSERT(0 <= index && index < frame_local_count_);
+    return Operand(ebp, kLocal0Offset - index * kPointerSize);
+  }
+
+  // The function frame slot.
+  Operand Function() const { return Operand(ebp, kFunctionOffset); }
+
+  // The context frame slot.
+  Operand Context() const { return Operand(ebp, kContextOffset); }
+
+  // A parameter as an assembly operand.
+  Operand Parameter(int index) const {
+    ASSERT(-1 <= index && index < parameter_count_);
+    return Operand(ebp, (1 + parameter_count_ - index) * kPointerSize);
+  }
+
+  // The receiver frame slot.
+  Operand Receiver() const { return Parameter(-1); }
+
+  // Push a try-catch or try-finally handler on top of the virtual frame.
+  inline void PushTryHandler(HandlerType type);
+
+  // Call a code stub, given the number of arguments it expects on (and
+  // removes from) the top of the physical frame.
+  inline void CallStub(CodeStub* stub, int frame_arg_count);
+
+  // Call the runtime, given the number of arguments expected on (and
+  // removed from) the top of the physical frame.
+  inline void CallRuntime(Runtime::Function* f, int frame_arg_count);
+  inline void CallRuntime(Runtime::FunctionId id, int frame_arg_count);
+
+  // Invoke a builtin, given the number of arguments it expects on (and
+  // removes from) the top of the physical frame.
+  inline void InvokeBuiltin(Builtins::JavaScript id,
+                            InvokeFlag flag,
+                            int frame_arg_count);
+
+  // Call into a JS code object, given the number of arguments it expects on
+  // (and removes from) the top of the physical frame.
+  inline void CallCode(Handle<Code> ic,
+                       RelocInfo::Mode rmode,
+                       int frame_arg_count);
+
+  // Drop a number of elements from the top of the expression stack.  May
+  // emit code to effect the physical frame.
+  inline void Drop(int count);
+
+  // Pop and discard an element from the top of the expression stack.
+  // Specifically does not clobber any registers excepting possibly the
+  // stack pointer.
+  inline void Pop();
+
+  // Pop and save an element from the top of the expression stack.  May emit
+  // code.
+  inline void Pop(Register reg);
+  inline void Pop(Operand operand);
+
+  // Push an element on top of the expression stack.  May emit code.
+  inline void Push(Register reg);
+  inline void Push(Operand operand);
+  inline void Push(Immediate immediate);
+
+ private:
+  static const int kLocal0Offset = JavaScriptFrameConstants::kLocal0Offset;
+  static const int kFunctionOffset = JavaScriptFrameConstants::kFunctionOffset;
+  static const int kContextOffset = StandardFrameConstants::kContextOffset;
+
+  static const int kHandlerSize = StackHandlerConstants::kSize / kPointerSize;
+
+  MacroAssembler* masm_;
+
+  // The number of frame-allocated locals and parameters respectively.
+  int frame_local_count_;
+  int parameter_count_;
+
+  // The height of the expression stack.
+  int height_;
+
+  // The JumpTarget class explicitly sets the height_ field of the expected
+  // frame at the actual return target.
+  friend class JumpTarget;
+};
+
+
+// -------------------------------------------------------------------------
+// Jump targets
+//
+// A jump target is an abstraction of a control-flow target in generated
+// code.  It encapsulates an assembler label and an expected virtual frame
+// layout at that label.  The first time control flow reaches the target,
+// either via jumping or branching or by binding the target, the expected
+// frame is set.  If control flow subsequently reaches the target, code may
+// be emitted to ensure that the current frame matches the expected frame.
+//
+// A jump target must have been reached via control flow (either by jumping,
+// branching, or falling through) when it is bound.  In particular, this
+// means that at least one of the control-flow graph edges reaching the
+// target must be a forward edge and must be compiled before any backward
+// edges.
+
+class JumpTarget : public ZoneObject {  // Shadows are dynamically allocated.
+ public:
+  // Construct a jump target with a given code generator used to generate
+  // code and to provide access to a current frame.
+  explicit JumpTarget(CodeGenerator* cgen);
+
+  // Construct a jump target without a code generator.  A code generator
+  // must be supplied before using the jump target as a label.  This is
+  // useful, eg, when jump targets are embedded in AST nodes.
+  JumpTarget();
+
+  virtual ~JumpTarget() { delete expected_frame_; }
+
+  // Supply a code generator.  This function expects to be given a non-null
+  // code generator, and to be called only when the code generator is not
+  // yet set.
+  void set_code_generator(CodeGenerator* cgen);
+
+  // Accessors.
+  CodeGenerator* code_generator() const { return code_generator_; }
+
+  MacroAssembler* masm() const { return masm_; }
+
+  Label* label() { return &label_; }
+
+  VirtualFrame* expected_frame() const { return expected_frame_; }
+  void set_expected_frame(VirtualFrame* frame) {
+    expected_frame_ = frame;
+  }
+
+  // Predicates testing the state of the encapsulated label.
+  bool is_bound() const { return label_.is_bound(); }
+  bool is_linked() const { return label_.is_linked(); }
+  bool is_unused() const { return label_.is_unused(); }
+
+  // Treat the jump target as a fresh one---the label is unused and the
+  // expected frame if any is reset.
+  void Unuse() {
+    label_.Unuse();
+    delete expected_frame_;
+    expected_frame_ = NULL;
+  }
+
+  // True if this jump target is the (non-shadowed) target of the return
+  // from the code generator's current function.
+  bool IsActualFunctionReturn();
+
+  // Emit a jump to the target.  If there is no expected frame, the code
+  // generator's current frame becomes the expected one.  If there is
+  // already an expected frame, code may be emitted to merge the current
+  // frame to the expected one.  After the jump, the code generate has no
+  // current frame (because control flow does not fall through from a jump).
+  // A new current frame can be picked up by, eg, binding a jump target with
+  // an expected frame.
+  void Jump();
+
+  // Emit a conditional branch to the target.  If there is no expected
+  // frame, a clone of the code generator's current frame becomes the
+  // expected one.  If there is already an expected frame, code may be
+  // emitted to merge the current frame to the expected one.
+  void Branch(Condition cc, Hint hint = no_hint);
+
+  // Bind a jump target.  If there is no expected frame and there is a
+  // current frame (ie, control flow is falling through to the target), then
+  // a clone of the current frame becomes the expected one.  If there is a
+  // current frame and an expected one (eg, control flow is falling through
+  // to a target that has already been reached via a jump or branch), then
+  // code may be emitted to merge the frames.  A jump target that already
+  // has an expected frame can be bound even if there is no current
+  // frame---in that case, the new current frame is picked up from the jump
+  // target.
+  void Bind();
+
+  // Call a jump target.  A clone of the current frame, with a return
+  // address pushed on top of it, becomes the expected frame at the target.
+  // The current frame after the site of the call (ie, after the return) is
+  // expected to be the same as before the call.  This operation is only
+  // supported when there is a current frame and when there is no expected
+  // frame at the label.
+  void Call();
+
+ protected:
+  // The encapsulated assembler label.
+  Label label_;
+
+  // The expected frame where the label is bound, or NULL.
+  VirtualFrame* expected_frame_;
+
+ private:
+  // The code generator gives access to the current frame.
+  CodeGenerator* code_generator_;
+
+  // Used to emit code.
+  MacroAssembler* masm_;
+};
+
+
+// -------------------------------------------------------------------------
+// Shadow jump targets
+//
+// Shadow jump targets represent a jump target that is temporarily shadowed
+// by another one (represented by the original during shadowing).  They are
+// used to catch jumps to labels in certain contexts, e.g. try blocks.
+// After shadowing ends, the formerly shadowed target is again represented
+// by the original and the ShadowTarget can be used as a jump target in its
+// own right, representing the formerly shadowing target.
+
+class ShadowTarget : public JumpTarget {
+ public:
+  // Construct a shadow a jump target.  After construction, the original
+  // jump target shadows the former target, which is hidden as the
+  // newly-constructed shadow target.
+  explicit ShadowTarget(JumpTarget* original);
+
+  virtual ~ShadowTarget() {
+    ASSERT(!is_shadowing_);
+  }
+
+  // End shadowing.  After shadowing ends, the original jump target gives
+  // access to the formerly shadowed target and the shadow target object
+  // gives access to the formerly shadowing target.
+  void StopShadowing();
+
+  // During shadowing, the currently shadowing target.  After shadowing, the
+  // target that was shadowed.
+  JumpTarget* original_target() const { return original_target_; }
+
+ private:
+  // During shadowing, the currently shadowing target.  After shadowing, the
+  // target that was shadowed.
+  JumpTarget* original_target_;
+
+  // During shadowing, the saved state of the shadowed target's label.
+  int original_pos_;
+
+  // During shadowing, the saved state of the shadowed target's expected
+  // frame.
+  VirtualFrame* original_expected_frame_;
+
+#ifdef DEBUG
+  bool is_shadowing_;
+#endif
+};
+
+
 // MacroAssembler implements a collection of frequently used macros.
 class MacroAssembler: public Assembler {
  public:
@@ -323,6 +623,117 @@
 }
 
 
+// -------------------------------------------------------------------------
+// VirtualFrame inline functions.
+
+#define __ masm_->
+
+void VirtualFrame::PushTryHandler(HandlerType type) {
+  // Grow the expression stack by handler size less two (the return address
+  // is already pushed by a call instruction, and PushTryHandler from the
+  // macro assembler will leave the top of stack in the eax register to be
+  // pushed separately).
+  height_ += (kHandlerSize - 2);
+  __ PushTryHandler(IN_JAVASCRIPT, type);
+  // TODO(1222589): remove the reliance of PushTryHandler on a cached TOS
+  Push(eax);
+}
+
+
+void VirtualFrame::CallStub(CodeStub* stub, int frame_arg_count) {
+  ASSERT(frame_arg_count >= 0);
+  ASSERT(height_ >= frame_arg_count);
+  height_ -= frame_arg_count;
+  __ CallStub(stub);
+}
+
+
+void VirtualFrame::CallRuntime(Runtime::Function* f, int frame_arg_count) {
+  ASSERT(frame_arg_count >= 0);
+  ASSERT(height_ >= frame_arg_count);
+  height_ -= frame_arg_count;
+  __ CallRuntime(f, frame_arg_count);
+}
+
+
+void VirtualFrame::CallRuntime(Runtime::FunctionId id, int frame_arg_count) {
+  ASSERT(frame_arg_count >= 0);
+  ASSERT(height_ >= frame_arg_count);
+  height_ -= frame_arg_count;
+  __ CallRuntime(id, frame_arg_count);
+}
+
+
+void VirtualFrame::InvokeBuiltin(Builtins::JavaScript id,
+                                 InvokeFlag flag,
+                                 int frame_arg_count) {
+  ASSERT(frame_arg_count >= 0);
+  ASSERT(height_ >= frame_arg_count);
+  height_ -= frame_arg_count;
+  __ InvokeBuiltin(id, flag);
+}
+
+
+void VirtualFrame::CallCode(Handle<Code> code,
+                            RelocInfo::Mode rmode,
+                            int frame_arg_count) {
+  ASSERT(frame_arg_count >= 0);
+  ASSERT(height_ >= frame_arg_count);
+  height_ -= frame_arg_count;
+  __ call(code, rmode);
+}
+
+
+void VirtualFrame::Drop(int count) {
+  ASSERT(count >= 0);
+  ASSERT(height_ >= count);
+  if (count > 0) {
+    __ add(Operand(esp), Immediate(count * kPointerSize));
+    height_ -= count;
+  }
+}
+
+
+void VirtualFrame::Pop() {
+  ASSERT(height_ > 0);
+  __ add(Operand(esp), Immediate(kPointerSize));
+  height_--;
+}
+
+
+void VirtualFrame::Pop(Register reg) {
+  ASSERT(height_ > 0);
+  __ pop(reg);
+  height_--;
+}
+
+
+void VirtualFrame::Pop(Operand operand) {
+  ASSERT(height_ > 0);
+  __ pop(operand);
+  height_--;
+}
+
+
+void VirtualFrame::Push(Register reg) {
+  height_++;
+  __ push(reg);
+}
+
+
+void VirtualFrame::Push(Operand operand) {
+  height_++;
+  __ push(operand);
+}
+
+
+void VirtualFrame::Push(Immediate immediate) {
+  height_++;
+  __ push(immediate);
+}
+
+#undef __
+
 } }  // namespace v8::internal
 
 #endif  // V8_MACRO_ASSEMBLER_IA32_H_