Improvements in lithium code generation. Recognizing if some operands are constants, we can often s…

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3178 matching lines @@
     LLoadExternalArrayPointer* instr) {
   Register result = ToRegister(instr->result());
   Register input = ToRegister(instr->object());
   __ mov(result, FieldOperand(input,
                               ExternalArray::kExternalPointerOffset));
 }
 
 
 void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
   Register arguments = ToRegister(instr->arguments());
-  Register length = ToRegister(instr->length());
-  Operand index = ToOperand(instr->index());
   Register result = ToRegister(instr->result());
-  // There are two words between the frame pointer and the last argument.
-  // Subtracting from length accounts for one of them add one more.
-  __ sub(length, index);
-  __ mov(result, Operand(arguments, length, times_4, kPointerSize));
+  if (instr->length()->IsConstantOperand() &&
+      instr->index()->IsConstantOperand()) {
+    int const_index = ToInteger32(LConstantOperand::cast(instr->index()));
+    int const_length = ToInteger32(LConstantOperand::cast(instr->length()));
+    int index = (const_length - const_index) + 1;
+    __ mov(result, Operand(arguments, index * kPointerSize));
+  } else {
+    Register length = ToRegister(instr->length());
+    Operand index = ToOperand(instr->index());
+    // There are two words between the frame pointer and the last argument.
+    // Subtracting from length accounts for one of them add one more.
+    __ sub(length, index);
+    __ mov(result, Operand(arguments, length, times_4, kPointerSize));
+  }
 }
 
 
 void LCodeGen::DoLoadKeyedExternalArray(LLoadKeyed* instr) {
   ElementsKind elements_kind = instr->elements_kind();
   LOperand* key = instr->key();
   if (!key->IsConstantOperand() &&
       ExternalArrayOpRequiresTemp(instr->hydrogen()->key()->representation(),
                                   elements_kind)) {
     __ SmiUntag(ToRegister(key));
@@ skipping 997 matching lines @@
 
 void LCodeGen::DoInnerAllocatedObject(LInnerAllocatedObject* instr) {
   Register result = ToRegister(instr->result());
   Register base = ToRegister(instr->base_object());
   __ lea(result, Operand(base, instr->offset()));
 }
 
 
 void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   Register object = ToRegister(instr->object());
-  Register value = ToRegister(instr->value());
   int offset = instr->offset();
 
   if (!instr->transition().is_null()) {
     if (!instr->hydrogen()->NeedsWriteBarrierForMap()) {
       __ mov(FieldOperand(object, HeapObject::kMapOffset), instr->transition());
     } else {
       Register temp = ToRegister(instr->temp());
       Register temp_map = ToRegister(instr->temp_map());
       __ mov(temp_map, instr->transition());
       __ mov(FieldOperand(object, HeapObject::kMapOffset), temp_map);
       // Update the write barrier for the map field.
       __ RecordWriteField(object,
                           HeapObject::kMapOffset,
                           temp_map,
                           temp,
                           GetSaveFPRegsMode(),
                           OMIT_REMEMBERED_SET,
                           OMIT_SMI_CHECK);
     }
   }
 
   // Do the store.
   HType type = instr->hydrogen()->value()->type();
   SmiCheck check_needed =
       type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
-  if (instr->is_in_object()) {
-    __ mov(FieldOperand(object, offset), value);
-    if (instr->hydrogen()->NeedsWriteBarrier()) {
-      Register temp = ToRegister(instr->temp());
-      // Update the write barrier for the object for in-object properties.
-      __ RecordWriteField(object,
-                          offset,
-                          value,
-                          temp,
-                          GetSaveFPRegsMode(),
-                          EMIT_REMEMBERED_SET,
-                          check_needed);
+
+  Register write_register = object;
+  if (!instr->is_in_object()) {
+    write_register = ToRegister(instr->temp());
+    __ mov(write_register,
+           FieldOperand(object, JSObject::kPropertiesOffset));
+  }
+
+  if (instr->value()->IsConstantOperand()) {
+    LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
+    if (IsInteger32(operand_value)) {
+      int const_value = ToInteger32(operand_value);
+      __ mov(FieldOperand(write_register, offset), Immediate(const_value));
+    } else {
+      if (operand_value->IsRegister()) {
+        __ mov(FieldOperand(write_register, offset), ToRegister(operand_value));
+      } else {
+        Handle<Object> handle_value = ToHandle(operand_value);
+        __ mov(FieldOperand(write_register, offset), handle_value);
+      }
     }
   } else {
-    Register temp = ToRegister(instr->temp());
-    __ mov(temp, FieldOperand(object, JSObject::kPropertiesOffset));
-    __ mov(FieldOperand(temp, offset), value);
-    if (instr->hydrogen()->NeedsWriteBarrier()) {
-      // Update the write barrier for the properties array.
-      // object is used as a scratch register.
-      __ RecordWriteField(temp,
-                          offset,
-                          value,
-                          object,
-                          GetSaveFPRegsMode(),
-                          EMIT_REMEMBERED_SET,
-                          check_needed);
-    }
+    __ mov(FieldOperand(write_register, offset), ToRegister(instr->value()));
+  }
+
+  if (instr->hydrogen()->NeedsWriteBarrier()) {
+    Register value = ToRegister(instr->value());
+    Register temp = instr->is_in_object() ? ToRegister(instr->temp()) : object;
+    // Update the write barrier for the object for in-object properties.
+    __ RecordWriteField(write_register,
+                        offset,
+                        value,
+                        temp,
+                        GetSaveFPRegsMode(),
+                        EMIT_REMEMBERED_SET,
+                        check_needed);
   }
 }
 
 
 void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* instr) {
   ASSERT(ToRegister(instr->context()).is(esi));
   ASSERT(ToRegister(instr->object()).is(edx));
   ASSERT(ToRegister(instr->value()).is(eax));
 
   __ mov(ecx, instr->name());
@@ skipping 157 matching lines @@
       }
 
       __ bind(&no_special_nan_handling);
       __ fst_d(double_store_operand);
     }
   }
 }
 
 
 void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
-  Register value = ToRegister(instr->value());
   Register elements = ToRegister(instr->elements());
   Register key = instr->key()->IsRegister() ? ToRegister(instr->key()) : no_reg;
 
   Operand operand = BuildFastArrayOperand(
       instr->elements(),
       instr->key(),
       instr->hydrogen()->key()->representation(),
       FAST_ELEMENTS,
       FixedArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
-  __ mov(operand, value);
+  if (instr->value()->IsRegister()) {
+    __ mov(operand, ToRegister(instr->value()));
+  } else {
+    LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
+    if (IsInteger32(operand_value)) {
+      int const_value = ToInteger32(operand_value);
+      __ mov(operand, Immediate(const_value));

[danno, 2013/04/18 15:37:54]

Shouldn't you store as a SMI?

[mvstanton, 2013/04/19 16:53:28]

Good catch, thanks. I'm wondering why a test didn't see this. 

+    } else {
+      Handle<Object> handle_value = ToHandle(operand_value);
+      __ mov(operand, handle_value);
+    }
+  }
 
   if (instr->hydrogen()->NeedsWriteBarrier()) {
+    ASSERT(instr->value()->IsRegister());
+    Register value = ToRegister(instr->value());
     ASSERT(!instr->key()->IsConstantOperand());
     HType type = instr->hydrogen()->value()->type();
     SmiCheck check_needed =
         type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
     // Compute address of modified element and store it into key register.
     __ lea(key, operand);
     __ RecordWrite(elements,
                    key,
                    value,
                    GetSaveFPRegsMode(),
@@ skipping 2071 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32