Reviewers: Mads Ager,
Description:
Optimize functions needing a local context.
Allocate the context in the prologue. Two issues had to be solved:
(1) deoptimization needs to handle functions with a local context,
(2) we need a safepoint in the prologue.
(Thanks to Kevin.)
Please review this at http://codereview.chromium.org/6534022/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/hydrogen.cc
M src/ia32/deoptimizer-ia32.cc
M src/ia32/lithium-codegen-ia32.cc
Index: src/hydrogen.cc
===================================================================
--- src/hydrogen.cc (revision 6838)
+++ src/hydrogen.cc (working copy)
@@ -2292,9 +2292,6 @@
// We don't yet handle the function name for named function expressions.
if (scope->function() != NULL) BAILOUT("named function expression");
- // We can't handle heap-allocated locals.
- if (scope->num_heap_slots() > 0) BAILOUT("heap allocated locals");
-
HConstant* undefined_constant =
new HConstant(Factory::undefined_value(), Representation::Tagged());
AddInstruction(undefined_constant);
@@ -2316,6 +2313,10 @@
// Handle the arguments and arguments shadow variables specially (they do
// not have declarations).
if (scope->arguments() != NULL) {
+ if (!scope->arguments()->IsStackAllocated() ||
+ !scope->arguments_shadow()->IsStackAllocated()) {
+ BAILOUT("context-allocated arguments");
+ }
HArgumentsObject* object = new HArgumentsObject;
AddInstruction(object);
graph()->SetArgumentsObject(object);
@@ -4023,6 +4024,7 @@
}
return false;
}
+ if (inner_info.scope()->num_heap_slots() > 0) return false;
FunctionLiteral* function = inner_info.function();
// Count the number of AST nodes added by inlining this call.
Index: src/ia32/deoptimizer-ia32.cc
===================================================================
--- src/ia32/deoptimizer-ia32.cc (revision 6838)
+++ src/ia32/deoptimizer-ia32.cc (working copy)
@@ -431,14 +431,16 @@
fp_value, output_offset, value);
}
- // The context can be gotten from the function so long as we don't
- // optimize functions that need local contexts.
+ // For the bottommost output frame the context can be gotten from the
input
+ // frame. For all subsequent output frames it can be gotten from the
function
+ // so long as we don't inline functions that need local contexts.
output_offset -= kPointerSize;
input_offset -= kPointerSize;
- value = reinterpret_cast<uint32_t>(function->context());
- // The context for the bottommost output frame should also agree with the
- // input frame.
- ASSERT(!is_bottommost || input_->GetFrameSlot(input_offset) == value);
+ if (is_bottommost) {
+ value = input_->GetFrameSlot(input_offset);
+ } else {
+ value = reinterpret_cast<uint32_t>(function->context());
+ }
output_frame->SetFrameSlot(output_offset, value);
if (is_topmost) output_frame->SetRegister(esi.code(), value);
if (FLAG_trace_deopt) {
Index: src/ia32/lithium-codegen-ia32.cc
===================================================================
--- src/ia32/lithium-codegen-ia32.cc (revision 6838)
+++ src/ia32/lithium-codegen-ia32.cc (working copy)
@@ -137,6 +137,46 @@
__ push(esi); // Callee's context.
__ push(edi); // Callee's JS function.
+ // Possibly allocate a local context.
+ int heap_slots = scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+ if (heap_slots > 0) {
+ Comment(";;; Allocate local context");
+ // Argument to NewContext is the function, which is still in edi.
+ __ push(edi);
+ if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+ FastNewContextStub stub(heap_slots);
+ __ CallStub(&stub);
+ } else {
+ __ CallRuntime(Runtime::kNewContext, 1);
+ }
+ safepoints_.DefineSafepoint(masm(), Safepoint::kSimple, 0,
+ Safepoint::kNoDeoptimizationIndex);
+ // Context is returned in both eax and esi. It replaces the context
+ // passed to us. It's saved in the stack and kept live in esi.
+ __ mov(Operand(ebp, StandardFrameConstants::kContextOffset), esi);
+
+ // Copy parameters into context if necessary.
+ int num_parameters = scope()->num_parameters();
+ for (int i = 0; i < num_parameters; i++) {
+ Slot* slot = scope()->parameter(i)->AsSlot();
+ if (slot != NULL && slot->type() == Slot::CONTEXT) {
+ int parameter_offset = StandardFrameConstants::kCallerSPOffset +
+ (num_parameters - 1 - i) * kPointerSize;
+ // Load parameter from stack.
+ __ mov(eax, Operand(ebp, parameter_offset));
+ // Store it in the context.
+ int context_offset = Context::SlotOffset(slot->index());
+ __ mov(Operand(esi, context_offset), eax);
+ // Update the write barrier. This clobbers all involved
+ // registers, so we have use a third register to avoid
+ // clobbering esi.
+ __ mov(ecx, esi);
+ __ RecordWrite(ecx, context_offset, eax, ebx);
+ }
+ }
+ Comment(";;; End allocate local context");
+ }
+
// Reserve space for the stack slots needed by the code.
int slots = StackSlotCount();
if (slots > 0) {
--
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