Revision: 3482
Author: [email protected]
Date: Thu Dec 17 00:53:19 2009
Log: Enable fast allocation of context objects on IA-32.
Review URL: http://codereview.chromium.org/507035
http://code.google.com/p/v8/source/detail?r=3482
Modified:
/branches/bleeding_edge/src/code-stubs.h
/branches/bleeding_edge/src/codegen.h
/branches/bleeding_edge/src/ia32/codegen-ia32.cc
=======================================
--- /branches/bleeding_edge/src/code-stubs.h Wed Dec 16 07:43:20 2009
+++ /branches/bleeding_edge/src/code-stubs.h Thu Dec 17 00:53:19 2009
@@ -44,6 +44,7 @@
V(WriteInt32ToHeapNumber) \
V(StackCheck) \
V(FastNewClosure) \
+ V(FastNewContext) \
V(UnarySub) \
V(RevertToNumber) \
V(ToBoolean) \
=======================================
--- /branches/bleeding_edge/src/codegen.h Wed Dec 16 07:43:20 2009
+++ /branches/bleeding_edge/src/codegen.h Thu Dec 17 00:53:19 2009
@@ -244,6 +244,25 @@
};
+class FastNewContextStub : public CodeStub {
+ public:
+ static const int kMaximumSlots = 64;
+
+ explicit FastNewContextStub(int slots) : slots_(slots) {
+ ASSERT(slots_ > 0 && slots <= kMaximumSlots);
+ }
+
+ void Generate(MacroAssembler* masm);
+
+ private:
+ int slots_;
+
+ const char* GetName() { return "FastNewContextStub"; }
+ Major MajorKey() { return FastNewContext; }
+ int MinorKey() { return slots_; }
+};
+
+
class InstanceofStub: public CodeStub {
public:
InstanceofStub() { }
=======================================
--- /branches/bleeding_edge/src/ia32/codegen-ia32.cc Wed Dec 16 23:35:12
2009
+++ /branches/bleeding_edge/src/ia32/codegen-ia32.cc Thu Dec 17 00:53:19
2009
@@ -174,12 +174,19 @@
function_return_is_shadowed_ = false;
// Allocate the local context if needed.
- if (scope_->num_heap_slots() > 0) {
+ int heap_slots = scope_->num_heap_slots();
+ if (heap_slots > 0) {
Comment cmnt(masm_, "[ allocate local context");
// Allocate local context.
// Get outer context and create a new context based on it.
frame_->PushFunction();
- Result context = frame_->CallRuntime(Runtime::kNewContext, 1);
+ Result context;
+ if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+ FastNewContextStub stub(heap_slots);
+ context = frame_->CallStub(&stub, 1);
+ } else {
+ context = frame_->CallRuntime(Runtime::kNewContext, 1);
+ }
// Update context local.
frame_->SaveContextRegister();
@@ -6588,6 +6595,47 @@
__ push(ecx); // Restore return address.
__ TailCallRuntime(ExternalReference(Runtime::kNewClosure), 2, 1);
}
+
+
+void FastNewContextStub::Generate(MacroAssembler* masm) {
+ // Try to allocate the context in new space.
+ Label gc;
+ int length = slots_ + Context::MIN_CONTEXT_SLOTS;
+ __ AllocateInNewSpace((length * kPointerSize) + FixedArray::kHeaderSize,
+ eax, ebx, ecx, &gc, TAG_OBJECT);
+
+ // Get the function from the stack.
+ __ mov(ecx, Operand(esp, 1 * kPointerSize));
+
+ // Setup the object header.
+ __ mov(FieldOperand(eax, HeapObject::kMapOffset),
Factory::context_map());
+ __ mov(FieldOperand(eax, Array::kLengthOffset), Immediate(length));
+
+ // Setup the fixed slots.
+ __ xor_(ebx, Operand(ebx)); // Set to NULL.
+ __ mov(Operand(eax, Context::SlotOffset(Context::CLOSURE_INDEX)), ecx);
+ __ mov(Operand(eax, Context::SlotOffset(Context::FCONTEXT_INDEX)), eax);
+ __ mov(Operand(eax, Context::SlotOffset(Context::PREVIOUS_INDEX)), ebx);
+ __ mov(Operand(eax, Context::SlotOffset(Context::EXTENSION_INDEX)), ebx);
+
+ // Copy the global object from the surrounding context.
+ __ mov(ebx, Operand(esi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+ __ mov(Operand(eax, Context::SlotOffset(Context::GLOBAL_INDEX)), ebx);
+
+ // Initialize the rest of the slots to undefined.
+ __ mov(ebx, Factory::undefined_value());
+ for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+ __ mov(Operand(eax, Context::SlotOffset(i)), ebx);
+ }
+
+ // Return and remove the on-stack parameter.
+ __ mov(esi, Operand(eax));
+ __ ret(1 * kPointerSize);
+
+ // Need to collect. Call into runtime system.
+ __ bind(&gc);
+ __ TailCallRuntime(ExternalReference(Runtime::kNewContext), 1, 1);
+}
// NOTE: The stub does not handle the inlined cases (Smis, Booleans,
undefined).
--
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