Reimplement stack manipulations for LiveEdit

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 1b625897d11dd732c4556fd8e3c6c7116702518c..7cae8a1826a0dd086d70eaa4f7f9c68502126c31 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -2423,13 +2423,10 @@ Object* Heap::CopyCode(Code* code) {
 }
 
 
-Object* Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
-  // Allocate ByteArray before the Code object, so that we do not risk
-  // leaving uninitialized Code object (and breaking the heap).
-  Object* reloc_info_array = AllocateByteArray(reloc_info.length(), TENURED);
-  if (reloc_info_array->IsFailure()) return reloc_info_array;
-
-  int new_body_size = RoundUp(code->instruction_size(), kObjectAlignment);
+Object* Heap::AddPatchToCode(Code* code, Code* patch) {
+  int space_size = patch->instruction_size();
+  int new_body_size = RoundUp(code->instruction_size() + space_size,
+      kObjectAlignment);
 
   int sinfo_size = code->sinfo_size();
 
@@ -2437,9 +2434,6 @@ Object* Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
 
   Address old_addr = code->address();
 
-  size_t relocation_offset =
-      static_cast<size_t>(code->instruction_end() - old_addr);
-
   Object* result;
   if (new_obj_size > MaxObjectSizeInPagedSpace()) {
     result = lo_space_->AllocateRawCode(new_obj_size);
@@ -2452,14 +2446,18 @@ Object* Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
   // Copy code object.
   Address new_addr = reinterpret_cast<HeapObject*>(result)->address();
 
+  int first_part_size =
+      code->instruction_start() + code->instruction_size() - old_addr;
+
   // Copy header and instructions.
-  memcpy(new_addr, old_addr, relocation_offset);
+  memcpy(new_addr, old_addr, first_part_size);
 
   Code* new_code = Code::cast(result);
-  new_code->set_relocation_info(ByteArray::cast(reloc_info_array));
+  new_code->set_instruction_size(code->instruction_size() + space_size);
+
+  // Copy patch instructions ignoring its rinfo/sinfo.
+  memcpy(new_addr + first_part_size, patch->instruction_start(), space_size);
 
-  // Copy patched rinfo.
-  memcpy(new_code->relocation_start(), reloc_info.start(), reloc_info.length());
   // Copy sinfo.
   memcpy(new_code->sinfo_start(), code->sinfo_start(), code->sinfo_size());
 
@@ -2468,7 +2466,7 @@ Object* Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
   new_code->Relocate(new_addr - old_addr);
 
 #ifdef DEBUG
-  code->Verify();
+  new_code->Verify();
 #endif
   return new_code;
 }