[crankshaft] do not restore rsi in stub for deferred number conversions

src/crankshaft/arm64/lithium-codegen-arm64.cc

 // Copyright 2013 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.
 
 #include "src/crankshaft/arm64/lithium-codegen-arm64.h"
 
 #include "src/arm64/frames-arm64.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 420 matching lines @@
   } else {
     UNREACHABLE();
   }
 }
 
 
 void LCodeGen::CallRuntimeFromDeferred(Runtime::FunctionId id,
                                        int argc,
                                        LInstruction* instr,
                                        LOperand* context) {
-  LoadContextFromDeferred(context);
+  if (context != nullptr) LoadContextFromDeferred(context);
   __ CallRuntimeSaveDoubles(id);
   RecordSafepointWithRegisters(
       instr->pointer_map(), argc, Safepoint::kNoLazyDeopt);
 }
 
 
 void LCodeGen::RecordSafepointWithLazyDeopt(LInstruction* instr,
                                             SafepointMode safepoint_mode) {
   if (safepoint_mode == RECORD_SIMPLE_SAFEPOINT) {
     RecordSafepoint(instr->pointer_map(), Safepoint::kLazyDeopt);
@@ skipping 996 matching lines @@
 }
 
 
 void LCodeGen::DoDeferredAllocate(LAllocate* instr) {
   // 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.
   __ Mov(ToRegister(instr->result()), Smi::FromInt(0));
 
   PushSafepointRegistersScope scope(this);
+  LoadContextFromDeferred(instr->context());
   // We're in a SafepointRegistersScope so we can use any scratch registers.
   Register size = x0;
   if (instr->size()->IsConstantOperand()) {
     __ Mov(size, ToSmi(LConstantOperand::cast(instr->size())));
   } else {
     __ SmiTag(size, ToRegister32(instr->size()).X());
   }
   int flags = AllocateDoubleAlignFlag::encode(
       instr->hydrogen()->MustAllocateDoubleAligned());
   if (instr->hydrogen()->IsOldSpaceAllocation()) {
     DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
     flags = AllocateTargetSpace::update(flags, OLD_SPACE);
   } else {
     flags = AllocateTargetSpace::update(flags, NEW_SPACE);
   }
   __ Mov(x10, Smi::FromInt(flags));
   __ Push(size, x10);
 
-  CallRuntimeFromDeferred(
-      Runtime::kAllocateInTargetSpace, 2, instr, instr->context());
+  CallRuntimeFromDeferred(Runtime::kAllocateInTargetSpace, 2, instr, nullptr);
   __ StoreToSafepointRegisterSlot(x0, ToRegister(instr->result()));
 
   if (instr->hydrogen()->IsAllocationFoldingDominator()) {
     AllocationFlags allocation_flags = NO_ALLOCATION_FLAGS;
     if (instr->hydrogen()->IsOldSpaceAllocation()) {
       DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
       allocation_flags = static_cast<AllocationFlags>(flags | PRETENURE);
     }
     // If the allocation folding dominator allocate triggered a GC, allocation
     // happend in the runtime. We have to reset the top pointer to virtually
@@ skipping 2700 matching lines @@
 
 
 void LCodeGen::DoDeferredNumberTagD(LNumberTagD* instr) {
   // 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.
   Register result = ToRegister(instr->result());
   __ Mov(result, 0);
 
   PushSafepointRegistersScope scope(this);
-  // NumberTagU and NumberTagD use the context from the frame, rather than
-  // the environment's HContext or HInlinedContext value.
-  // They only call Runtime::kAllocateHeapNumber.
-  // The corresponding HChange instructions are added in a phase that does
-  // not have easy access to the local context.
-  __ Ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+  // Reset the context register.
+  if (!result.is(cp)) {
+    __ Mov(cp, 0);
+  }
   __ CallRuntimeSaveDoubles(Runtime::kAllocateHeapNumber);
   RecordSafepointWithRegisters(
       instr->pointer_map(), 0, Safepoint::kNoLazyDeopt);
   __ StoreToSafepointRegisterSlot(x0, result);
 }
 
 
 void LCodeGen::DoNumberTagD(LNumberTagD* instr) {
   class DeferredNumberTagD: public LDeferredCode {
    public:
@@ skipping 39 matching lines @@
 
   // Slow case: call the runtime system to do the number allocation.
   __ Bind(&slow);
   // TODO(3095996): Put a valid pointer value in the stack slot where the result
   // register is stored, as this register is in the pointer map, but contains an
   // integer value.
   __ Mov(dst, 0);
   {
     // Preserve the value of all registers.
     PushSafepointRegistersScope scope(this);
-
-    // NumberTagU and NumberTagD use the context from the frame, rather than
-    // the environment's HContext or HInlinedContext value.
-    // They only call Runtime::kAllocateHeapNumber.
-    // The corresponding HChange instructions are added in a phase that does
-    // not have easy access to the local context.
-    __ Ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+    // Reset the context register.
+    if (!dst.is(cp)) {
+      __ Mov(cp, 0);
+    }
     __ CallRuntimeSaveDoubles(Runtime::kAllocateHeapNumber);
     RecordSafepointWithRegisters(
       instr->pointer_map(), 0, Safepoint::kNoLazyDeopt);
     __ StoreToSafepointRegisterSlot(x0, dst);
   }
 
   // Convert number to floating point and store in the newly allocated heap
   // number.
   __ Bind(&convert_and_store);
   DoubleRegister dbl_scratch = double_scratch();
@@ skipping 1439 matching lines @@
   // Index is equal to negated out of object property index plus 1.
   __ Sub(result, result, Operand::UntagSmiAndScale(index, kPointerSizeLog2));
   __ Ldr(result, FieldMemOperand(result,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ Bind(deferred->exit());
   __ Bind(&done);
 }
 
 }  // namespace internal
 }  // namespace v8