Improve algorithm for detaching and attaching a virtual frame to the code

generator.  Inline copying of a register file.
Review URL: http://codereview.chromium.org/113402

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1954 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/virtual-frame-arm.h

@@ -127,13 +127,29 @@ class VirtualFrame : public ZoneObject {
   // 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();
+  void DetachFromCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Unuse(temp);
+      }
+    }
+  }
 
   // (Re)attach a frame to its code generator.  This informs the register
   // allocator that the frame-internal register references are active again.
   // Used when a code generator's frame is switched from NULL to this one by
   // binding a label.
-  void AttachToCodeGenerator();
+  void AttachToCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Use(temp);
+      }
+    }
+  }
 
   // Emit code for the physical JS entry and exit frame sequences.  After
   // calling Enter, the virtual frame is ready for use; and after calling

src/ia32/virtual-frame-ia32.h

@@ -130,13 +130,29 @@ class VirtualFrame : public ZoneObject {
   // 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();
+  void DetachFromCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Unuse(temp);
+      }
+    }
+  }
 
   // (Re)attach a frame to its code generator.  This informs the register
   // allocator that the frame-internal register references are active again.
   // Used when a code generator's frame is switched from NULL to this one by
   // binding a label.
-  void AttachToCodeGenerator();
+  void AttachToCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Use(temp);
+      }
+    }
+  }
 
   // Emit code for the physical JS entry and exit frame sequences.  After
   // calling Enter, the virtual frame is ready for use; and after calling

src/register-allocator.cc

@@ -71,16 +71,6 @@ void Result::CopyTo(Result* destination) const {
 }
 
 
-// -------------------------------------------------------------------------
-// RegisterFile implementation.
-
-void RegisterFile::CopyTo(RegisterFile* other) {
-  for (int i = 0; i < kNumRegisters; i++) {
-    other->ref_counts_[i] = ref_counts_[i];
-  }
-}
-
-
 // -------------------------------------------------------------------------
 // RegisterAllocator implementation.
 

src/register-allocator.h

@@ -243,7 +243,11 @@ class RegisterFile BASE_EMBEDDED {
   }
 
   // Copy the reference counts from this register file to the other.
-  void CopyTo(RegisterFile* other);
+  void CopyTo(RegisterFile* other) {
+    for (int i = 0; i < kNumRegisters; i++) {
+      other->ref_counts_[i] = ref_counts_[i];
+    }
+  }
 
  private:
   int ref_counts_[kNumRegisters];

src/virtual-frame.cc

@@ -304,30 +304,6 @@ void VirtualFrame::PrepareForCall(int spilled_args, int dropped_args) {
 }
 
 
-void VirtualFrame::DetachFromCodeGenerator() {
-  // Tell the global register allocator that it is free to reallocate all
-  // register references contained in this frame.  The frame elements remain
-  // register references, so the frame-internal reference count is not
-  // decremented.
-  for (int i = 0; i < elements_.length(); i++) {
-    if (elements_[i].is_register()) {
-      cgen_->allocator()->Unuse(elements_[i].reg());
-    }
-  }
-}
-
-
-void VirtualFrame::AttachToCodeGenerator() {
-  // Tell the global register allocator that the frame-internal register
-  // references are live again.
-  for (int i = 0; i < elements_.length(); i++) {
-    if (elements_[i].is_register()) {
-      cgen_->allocator()->Use(elements_[i].reg());
-    }
-  }
-}
-
-
 void VirtualFrame::PrepareForReturn() {
   // Spill all locals. This is necessary to make sure all locals have
   // the right value when breaking at the return site in the debugger.

src/x64/virtual-frame-x64.h

@@ -130,13 +130,28 @@ class VirtualFrame : public Malloced {
   // 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();
-
+  void DetachFromCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Unuse(temp);
+      }
+    }
+  }
   // (Re)attach a frame to its code generator.  This informs the register
   // allocator that the frame-internal register references are active again.
   // Used when a code generator's frame is switched from NULL to this one by
   // binding a label.
-  void AttachToCodeGenerator();
+  void AttachToCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Use(temp);
+      }
+    }
+  }
 
   // Emit code for the physical JS entry and exit frame sequences.  After
   // calling Enter, the virtual frame is ready for use; and after calling