Refactor and improve inlined double-aligned allocations

src/arm/macro-assembler-arm.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 1599 matching lines @@
       // immediately below so this use of ip does not cause difference with
       // respect to register content between debug and release mode.
       ldr(ip, MemOperand(topaddr));
       cmp(result, ip);
       Check(eq, "Unexpected allocation top");
     }
     // Load allocation limit into ip. Result already contains allocation top.
     ldr(ip, MemOperand(topaddr, limit - top));
   }
 
+  if ((flags & DOUBLE_ALIGNMENT) != 0) {
+    // Align the next allocation. Storing the filler map without checking top is
+    // always safe because the limit of the heap is always aligned.
+    ASSERT(kPointerAlignment * 2 == kDoubleAlignment);
+    and_(scratch2, result, Operand(kDoubleAlignmentMask), SetCC);
+    Label aligned;
+    b(eq, &aligned);
+    mov(scratch2, Operand(isolate()->factory()->one_pointer_filler_map()));
+    str(scratch2, MemOperand(result, kDoubleSize / 2, PostIndex));
+    bind(&aligned);
+  }
+
   // Calculate new top and bail out if new space is exhausted. Use result
   // to calculate the new top.
   if (obj_size_operand.is_single_instruction(this)) {
     // We can add the size as an immediate
     add(scratch2, result, obj_size_operand, SetCC);
   } else {
     // Doesn't fit in an immediate, we have to use the register
     add(scratch2, result, obj_size_reg, SetCC);
   }
   b(cs, gc_required);
@@ skipping 65 matching lines @@
       // immediately below so this use of ip does not cause difference with
       // respect to register content between debug and release mode.
       ldr(ip, MemOperand(topaddr));
       cmp(result, ip);
       Check(eq, "Unexpected allocation top");
     }
     // Load allocation limit into ip. Result already contains allocation top.
     ldr(ip, MemOperand(topaddr, limit - top));
   }
 
+  if ((flags & DOUBLE_ALIGNMENT) != 0) {
+    // Align the next allocation. Storing the filler map without checking top is
+    // always safe because the limit of the heap is always aligned.
+    ASSERT(kPointerAlignment * 2 == kDoubleAlignment);
+    and_(scratch2, result, Operand(kDoubleAlignmentMask), SetCC);
+    Label aligned;
+    b(eq, &aligned);
+    mov(scratch2, Operand(isolate()->factory()->one_pointer_filler_map()));
+    str(scratch2, MemOperand(result, kDoubleSize / 2, PostIndex));
+    bind(&aligned);
+  }
+
   // Calculate new top and bail out if new space is exhausted. Use result
   // to calculate the new top. Object size may be in words so a shift is
   // required to get the number of bytes.
   if ((flags & SIZE_IN_WORDS) != 0) {
     add(scratch2, result, Operand(object_size, LSL, kPointerSizeLog2), SetCC);
   } else {
     add(scratch2, result, Operand(object_size), SetCC);
   }
   b(cs, gc_required);
   cmp(scratch2, Operand(ip));
@@ skipping 2201 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM