ARM: Remove a bunch of spilled scopes. Still a lot to go.

Review URL: http://codereview.chromium.org/2828004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4932 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/jump-target-arm.cc

@@ -61,9 +61,17 @@ void JumpTarget::DoJump() {
   } else {
     // Clone the current frame to use as the expected one at the target.
     set_entry_frame(cgen()->frame());
+    // Zap the fall-through frame since the jump was unconditional.
     RegisterFile empty;
     cgen()->SetFrame(NULL, &empty);
   }
+  if (entry_label_.is_bound()) {
+    // You can't jump backwards to an already bound label unless you admitted
+    // up front that this was a bidirectional jump target.  Bidirectional jump
+    // targets will zap their type info when bound in case some later virtual
+    // frame with less precise type info branches to them.
+    ASSERT(direction_ != FORWARD_ONLY);
+  }
   __ jmp(&entry_label_);
 }
 
@@ -83,6 +91,13 @@ void JumpTarget::DoBranch(Condition cc, Hint ignored) {
     // Clone the current frame to use as the expected one at the target.
     set_entry_frame(cgen()->frame());
   }
+  if (entry_label_.is_bound()) {
+    // You can't branch backwards to an already bound label unless you admitted
+    // up front that this was a bidirectional jump target.  Bidirectional jump
+    // targets will zap their type info when bound in case some later virtual
+    // frame with less precise type info branches to them.
+    ASSERT(direction_ != FORWARD_ONLY);
+  }
   __ b(cc, &entry_label_);
   if (cc == al) {
     cgen()->DeleteFrame();
@@ -121,6 +136,7 @@ void JumpTarget::DoBind() {
   ASSERT(!cgen()->has_valid_frame() || cgen()->HasValidEntryRegisters());
 
   if (cgen()->has_valid_frame()) {
+    if (direction_ != FORWARD_ONLY) cgen()->frame()->ForgetTypeInfo();
     // If there is a current frame we can use it on the fall through.
     if (!entry_frame_set_) {
       entry_frame_ = *cgen()->frame();

src/arm/virtual-frame-arm.cc

@@ -482,6 +482,32 @@ void VirtualFrame::SpillAllButCopyTOSToR0() {
 }
 
 
+void VirtualFrame::SpillAllButCopyTOSToR1() {
+  switch (top_of_stack_state_) {
+    case NO_TOS_REGISTERS:
+      __ ldr(r1, MemOperand(sp, 0));
+      break;
+    case R0_TOS:
+      __ push(r0);
+      __ mov(r1, r0);
+      break;
+    case R1_TOS:
+      __ push(r1);
+      break;
+    case R0_R1_TOS:
+      __ Push(r1, r0);
+      __ mov(r1, r0);
+      break;
+    case R1_R0_TOS:
+      __ Push(r0, r1);
+      break;
+    default:
+      UNREACHABLE();
+  }
+  top_of_stack_state_ = NO_TOS_REGISTERS;
+}
+
+
 void VirtualFrame::SpillAllButCopyTOSToR1R0() {
   switch (top_of_stack_state_) {
     case NO_TOS_REGISTERS:
@@ -524,6 +550,24 @@ Register VirtualFrame::Peek() {
 }
 
 
+Register VirtualFrame::Peek2() {
+  AssertIsNotSpilled();
+  switch (top_of_stack_state_) {
+    case NO_TOS_REGISTERS:
+    case R0_TOS:
+    case R0_R1_TOS:
+      MergeTOSTo(R0_R1_TOS);
+      return r1;
+    case R1_TOS:
+    case R1_R0_TOS:
+      MergeTOSTo(R1_R0_TOS);
+      return r0;
+  }
+  UNREACHABLE();
+  return no_reg;
+}
+
+
 void VirtualFrame::Dup() {
   if (SpilledScope::is_spilled()) {
     __ ldr(ip, MemOperand(sp, 0));

src/arm/virtual-frame-arm.h

@@ -189,12 +189,15 @@ class VirtualFrame : public ZoneObject {
     return (tos_known_smi_map_ & (~other->tos_known_smi_map_)) == 0;
   }
 
+  inline void ForgetTypeInfo() {
+    tos_known_smi_map_ = 0;
+  }
+
   // Detach a frame from its code generator, perhaps temporarily.  This
   // tells the register allocator that it is free to use frame-internal
   // registers.  Used when the code generator's frame is switched from this
   // one to NULL by an unconditional jump.
   void DetachFromCodeGenerator() {
-    AssertIsSpilled();
   }
 
   // (Re)attach a frame to its code generator.  This informs the register
@@ -202,7 +205,6 @@ class VirtualFrame : public ZoneObject {
   // Used when a code generator's frame is switched from NULL to this one by
   // binding a label.
   void AttachToCodeGenerator() {
-    AssertIsSpilled();
   }
 
   // Emit code for the physical JS entry and exit frame sequences.  After
@@ -330,6 +332,10 @@ class VirtualFrame : public ZoneObject {
   // must be copied to a scratch register before modification.
   Register Peek();
 
+  // Look at the value beneath the top of the stack.  The register returned is
+  // aliased and must be copied to a scratch register before modification.
+  Register Peek2();
+
   // Duplicate the top of stack.
   void Dup();
 
@@ -339,6 +345,9 @@ class VirtualFrame : public ZoneObject {
   // Flushes all registers, but it puts a copy of the top-of-stack in r0.
   void SpillAllButCopyTOSToR0();
 
+  // Flushes all registers, but it puts a copy of the top-of-stack in r1.
+  void SpillAllButCopyTOSToR1();
+
   // Flushes all registers, but it puts a copy of the top-of-stack in r1
   // and the next value on the stack in r0.
   void SpillAllButCopyTOSToR1R0();

src/ast-inl.h

@@ -45,7 +45,9 @@ SwitchStatement::SwitchStatement(ZoneStringList* labels)
 
 
 IterationStatement::IterationStatement(ZoneStringList* labels)
-    : BreakableStatement(labels, TARGET_FOR_ANONYMOUS), body_(NULL) {
+    : BreakableStatement(labels, TARGET_FOR_ANONYMOUS),
+      body_(NULL),
+      continue_target_(JumpTarget::BIDIRECTIONAL) {
 }
 
 

src/jump-target-heavy.h

@@ -196,6 +196,8 @@ class BreakTarget : public JumpTarget {
  public:
   // Construct a break target.
   BreakTarget() {}
+  explicit BreakTarget(JumpTarget::Directionality direction)
+    : JumpTarget(direction) { }
 
   virtual ~BreakTarget() {}
 

src/jump-target-light-inl.h

@@ -36,16 +36,20 @@ namespace internal {
 // Construct a jump target.
 JumpTarget::JumpTarget(Directionality direction)
     : entry_frame_set_(false),
+      direction_(direction),
       entry_frame_(kInvalidVirtualFrameInitializer) {
 }
 
 JumpTarget::JumpTarget()
     : entry_frame_set_(false),
+      direction_(FORWARD_ONLY),
       entry_frame_(kInvalidVirtualFrameInitializer) {
 }
 
 
 BreakTarget::BreakTarget() { }
+BreakTarget::BreakTarget(JumpTarget::Directionality direction)
+  : JumpTarget(direction) { }
 
 } }  // namespace v8::internal
 

src/jump-target-light.h

@@ -120,6 +120,9 @@ class JumpTarget : public ZoneObject {  // Shadows are dynamically allocated.
   // Has an entry frame been found?
   bool entry_frame_set_;
 
+  // Can we branch backwards to this label?
+  Directionality direction_;
+
   // The frame used on entry to the block and expected at backward
   // jumps to the block.  Set the first time something branches to this
   // jump target.
@@ -150,6 +153,7 @@ class BreakTarget : public JumpTarget {
  public:
   // Construct a break target.
   inline BreakTarget();
+  inline BreakTarget(JumpTarget::Directionality direction);
 
   virtual ~BreakTarget() {}