[crankshaft] Loads and stores to typed arrays have to reference the backing store holder

src/crankshaft/x64/lithium-x64.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.
 
 #include "src/crankshaft/x64/lithium-x64.h"
 
 #include <sstream>
 
 #if V8_TARGET_ARCH_X64
 
@@ skipping 2172 matching lines @@
         ? UseTempRegister(instr->key())
         : UseRegisterOrConstantAtStart(instr->key());
   }
 
   if ((kPointerSize == kInt64Size) && instr->IsDehoisted()) {
     FindDehoistedKeyDefinitions(instr->key());
   }
 
   if (!instr->is_fixed_typed_array()) {
     LOperand* obj = UseRegisterAtStart(instr->elements());
-    result = DefineAsRegister(new(zone()) LLoadKeyed(obj, key));
+    result = DefineAsRegister(new (zone()) LLoadKeyed(obj, key, nullptr));
   } else {
     DCHECK(
         (instr->representation().IsInteger32() &&
          !(IsDoubleOrFloatElementsKind(elements_kind))) ||
         (instr->representation().IsDouble() &&
          (IsDoubleOrFloatElementsKind(elements_kind))));
     LOperand* backing_store = UseRegister(instr->elements());
-    result = DefineAsRegister(new(zone()) LLoadKeyed(backing_store, key));
+    LOperand* backing_store_owner = UseAny(instr->backing_store_owner());

[Benedikt Meurer, 2015/12/07 05:02:03]

I think UseAny in this case will prevent aliasing of backing_store_owner and
result, which means you need at least 4 free registers for this instruction,
even tho 3 would suffice. But given that we are sort of sloppy about the
constraints in this case anyway (i.e. UseRegister always on instr->elements())
it's probably fine to say UseAny here.

+    result = DefineAsRegister(
+        new (zone()) LLoadKeyed(backing_store, key, backing_store_owner));
   }
 
   bool needs_environment;
   if (instr->is_fixed_typed_array()) {
     // see LCodeGen::DoLoadKeyedExternalArray
     needs_environment = elements_kind == UINT32_ELEMENTS &&
                         !instr->CheckFlag(HInstruction::kUint32);
   } else {
     // see LCodeGen::DoLoadKeyedFixedDoubleArray and
     // LCodeGen::DoLoadKeyedFixedArray
@@ skipping 51 matching lines @@
         object = UseTempRegister(instr->elements());
         val = UseTempRegister(instr->value());
         key = UseTempRegister(instr->key());
       } else {
         object = UseRegisterAtStart(instr->elements());
         val = UseRegisterOrConstantAtStart(instr->value());
         key = UseRegisterOrConstantAtStart(instr->key());
       }
     }
 
-    return new(zone()) LStoreKeyed(object, key, val);
+    return new (zone()) LStoreKeyed(object, key, val, nullptr);
   }
 
   DCHECK(
        (instr->value()->representation().IsInteger32() &&
        !IsDoubleOrFloatElementsKind(elements_kind)) ||
        (instr->value()->representation().IsDouble() &&
        IsDoubleOrFloatElementsKind(elements_kind)));
   DCHECK(instr->elements()->representation().IsExternal());
   bool val_is_temp_register = elements_kind == UINT8_CLAMPED_ELEMENTS ||
                               elements_kind == FLOAT32_ELEMENTS;
   LOperand* val = val_is_temp_register ? UseTempRegister(instr->value())
       : UseRegister(instr->value());
   LOperand* key = NULL;
   if (kPointerSize == kInt64Size) {
     key = UseRegisterOrConstantAtStart(instr->key());
   } else {
     bool clobbers_key = ExternalArrayOpRequiresTemp(
         instr->key()->representation(), elements_kind);
     key = clobbers_key
         ? UseTempRegister(instr->key())
         : UseRegisterOrConstantAtStart(instr->key());
   }
   LOperand* backing_store = UseRegister(instr->elements());
-  return new(zone()) LStoreKeyed(backing_store, key, val);
+  LOperand* backing_store_owner = UseAny(instr->backing_store_owner());

[Benedikt Meurer, 2015/12/07 05:02:03]

Hm, I'm not sure if UseAny is the ideal choice here; but my knowledge about the
lithium allocator is close to zero at this point, so it's probably OK even tho
not 100% ideal.

+  return new (zone()) LStoreKeyed(backing_store, key, val, backing_store_owner);
 }
 
 
 LInstruction* LChunkBuilder::DoStoreKeyedGeneric(HStoreKeyedGeneric* instr) {
   LOperand* context = UseFixed(instr->context(), rsi);
   LOperand* object =
       UseFixed(instr->object(), StoreDescriptor::ReceiverRegister());
   LOperand* key = UseFixed(instr->key(), StoreDescriptor::NameRegister());
   LOperand* value = UseFixed(instr->value(), StoreDescriptor::ValueRegister());
 
@@ skipping 372 matching lines @@
   LAllocateBlockContext* result =
       new(zone()) LAllocateBlockContext(context, function);
   return MarkAsCall(DefineFixed(result, rsi), instr);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64