X87: [crankshaft] Fragmentation-free allocation folding.

src/crankshaft/x87/lithium-codegen-x87.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/crankshaft/x87/lithium-codegen-x87.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 5438 matching lines @@
     }
     Label loop;
     __ bind(&loop);
     __ mov(FieldOperand(result, temp, times_pointer_size, 0),
         isolate()->factory()->one_pointer_filler_map());
     __ dec(temp);
     __ j(not_zero, &loop);
   }
 }
 
+void LCodeGen::DoFastAllocate(LFastAllocate* instr) {

[Hannes Payer (out of office), 2016/05/11 07:44:41]

Why do you move that piece of code? I would like to keep the order in sync with
the other platforms: DoAllocate, DoDeferredAllocate, DoFastAllocate.

+  DCHECK(instr->hydrogen()->IsAllocationFolded());
+  Register result = ToRegister(instr->result());
+  Register temp = ToRegister(instr->temp());
+
+  AllocationFlags flags = NO_ALLOCATION_FLAGS;
+  if (instr->hydrogen()->MustAllocateDoubleAligned()) {
+    flags = static_cast<AllocationFlags>(flags | DOUBLE_ALIGNMENT);
+  }
+  if (instr->hydrogen()->IsOldSpaceAllocation()) {
+    DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
+    flags = static_cast<AllocationFlags>(flags | PRETENURE);
+  }
+  if (!instr->hydrogen()->IsAllocationFoldingDominator()) {
+    if (instr->size()->IsConstantOperand()) {
+      int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
+      CHECK(size <= Page::kMaxRegularHeapObjectSize);
+      __ FastAllocate(size, result, temp, flags);
+    } else {
+      Register size = ToRegister(instr->size());
+      __ FastAllocate(size, result, temp, flags);
+    }
+  }
+}
 
 void LCodeGen::DoDeferredAllocate(LAllocate* instr) {
   Register result = ToRegister(instr->result());
 
   // TODO(3095996): Get rid of this. For now, we need to make the
   // result register contain a valid pointer because it is already
   // contained in the register pointer map.
   __ Move(result, Immediate(Smi::FromInt(0)));
 
   PushSafepointRegistersScope scope(this);
@@ skipping 37 matching lines @@
     // happend in the runtime. We have to reset the top pointer to virtually
     // undo the allocation.
     ExternalReference allocation_top =
         AllocationUtils::GetAllocationTopReference(isolate(), allocation_flags);
     __ sub(eax, Immediate(kHeapObjectTag));
     __ mov(Operand::StaticVariable(allocation_top), eax);
     __ add(eax, Immediate(kHeapObjectTag));
   }
 }
 
-void LCodeGen::DoFastAllocate(LFastAllocate* instr) {
-  DCHECK(instr->hydrogen()->IsAllocationFolded());
-  Register result = ToRegister(instr->result());
-  Register temp = ToRegister(instr->temp());
-
-  AllocationFlags flags = NO_ALLOCATION_FLAGS;
-  if (instr->hydrogen()->MustAllocateDoubleAligned()) {
-    flags = static_cast<AllocationFlags>(flags | DOUBLE_ALIGNMENT);
-  }
-  if (instr->hydrogen()->IsOldSpaceAllocation()) {
-    DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
-    flags = static_cast<AllocationFlags>(flags | PRETENURE);
-  }
-  if (!instr->hydrogen()->IsAllocationFoldingDominator()) {
-    if (instr->size()->IsConstantOperand()) {
-      int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
-      CHECK(size <= Page::kMaxRegularHeapObjectSize);
-      __ FastAllocate(size, result, temp, flags);
-    } else {
-      Register size = ToRegister(instr->size());
-      __ FastAllocate(size, result, temp, flags);
-    }
-  }
-}
-
 
 void LCodeGen::DoTypeof(LTypeof* instr) {
   DCHECK(ToRegister(instr->context()).is(esi));
   DCHECK(ToRegister(instr->value()).is(ebx));
   Label end, do_call;
   Register value_register = ToRegister(instr->value());
   __ JumpIfNotSmi(value_register, &do_call);
   __ mov(eax, Immediate(isolate()->factory()->number_string()));
   __ jmp(&end);
   __ bind(&do_call);
@@ skipping 338 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87