Fix crashes during GC caused by partially initialized objects. The...

src/ia32/macro-assembler-ia32.cc

 // Copyright 2006-2009 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 519 matching lines @@
   mov(scratch, FieldOperand(scratch, token_offset));
   cmp(scratch, FieldOperand(holder_reg, token_offset));
   pop(holder_reg);
   j(not_equal, miss, not_taken);
 
   bind(&same_contexts);
 }
 
 
 void MacroAssembler::LoadAllocationTopHelper(Register result,
-                                             Register result_end,
                                              Register scratch,
                                              AllocationFlags flags) {
   ExternalReference new_space_allocation_top =
       ExternalReference::new_space_allocation_top_address();
 
   // Just return if allocation top is already known.
   if ((flags & RESULT_CONTAINS_TOP) != 0) {
     // No use of scratch if allocation top is provided.
     ASSERT(scratch.is(no_reg));
 #ifdef DEBUG
     // Assert that result actually contains top on entry.
     cmp(result, Operand::StaticVariable(new_space_allocation_top));
     Check(equal, "Unexpected allocation top");
 #endif
     return;
   }
 
   // Move address of new object to result. Use scratch register if available.
   if (scratch.is(no_reg)) {
     mov(result, Operand::StaticVariable(new_space_allocation_top));
   } else {
-    ASSERT(!scratch.is(result_end));
     mov(Operand(scratch), Immediate(new_space_allocation_top));
     mov(result, Operand(scratch, 0));
   }
 }
 
 
 void MacroAssembler::UpdateAllocationTopHelper(Register result_end,
                                                Register scratch) {
   if (FLAG_debug_code) {
     test(result_end, Immediate(kObjectAlignmentMask));
@@ skipping 28 matching lines @@
       if (scratch.is_valid()) {
         mov(scratch, Immediate(0x7291));
       }
     }
     jmp(gc_required);
     return;
   }
   ASSERT(!result.is(result_end));
 
   // Load address of new object into result.
-  LoadAllocationTopHelper(result, result_end, scratch, flags);
+  LoadAllocationTopHelper(result, scratch, flags);
 
   Register top_reg = result_end.is_valid() ? result_end : result;
 
   // Calculate new top and bail out if new space is exhausted.
   ExternalReference new_space_allocation_limit =
       ExternalReference::new_space_allocation_limit_address();
 
   if (top_reg.is(result)) {
     add(Operand(top_reg), Immediate(object_size));
   } else {
@@ skipping 35 matching lines @@
         mov(scratch, Immediate(0x7291));
       }
       // Register element_count is not modified by the function.
     }
     jmp(gc_required);
     return;
   }
   ASSERT(!result.is(result_end));
 
   // Load address of new object into result.
-  LoadAllocationTopHelper(result, result_end, scratch, flags);
+  LoadAllocationTopHelper(result, scratch, flags);
 
   // Calculate new top and bail out if new space is exhausted.
   ExternalReference new_space_allocation_limit =
       ExternalReference::new_space_allocation_limit_address();
   lea(result_end, Operand(result, element_count, element_size, header_size));
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required);
 
   // Tag result if requested.
   if ((flags & TAG_OBJECT) != 0) {
@@ skipping 20 matching lines @@
         mov(scratch, Immediate(0x7291));
       }
       // object_size is left unchanged by this function.
     }
     jmp(gc_required);
     return;
   }
   ASSERT(!result.is(result_end));
 
   // Load address of new object into result.
-  LoadAllocationTopHelper(result, result_end, scratch, flags);
+  LoadAllocationTopHelper(result, scratch, flags);
 
   // Calculate new top and bail out if new space is exhausted.
   ExternalReference new_space_allocation_limit =
       ExternalReference::new_space_allocation_limit_address();
   if (!object_size.is(result_end)) {
     mov(result_end, object_size);
   }
   add(result_end, Operand(result));
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required, not_taken);
@@ skipping 1140 matching lines @@
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32