Reviewers: Erik Corry,
Message:
Hi Erik
Do you think it looks like a fix for
http://code.google.com/p/v8/issues/detail?id=915
?
Peter
Description:
Fix for Issue 915
Please review this at http://codereview.chromium.org/10332101/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/liveedit.cc
Index: src/liveedit.cc
diff --git a/src/liveedit.cc b/src/liveedit.cc
index
22b82501e91f244b7bf16839e30ffb295c51e34d..76da4fc8424a076d703a940a2b7a14f63d03d97c
100644
--- a/src/liveedit.cc
+++ b/src/liveedit.cc
@@ -922,33 +922,37 @@ void
LiveEdit::WrapSharedFunctionInfos(Handle<JSArray> array) {
}
-// Visitor that collects all references to a particular code object,
-// including "CODE_TARGET" references in other code objects.
-// It works in context of ZoneScope.
-class ReferenceCollectorVisitor : public ObjectVisitor {
+// Visitor that finds all references to a particular code object,
+// including "CODE_TARGET" references in other code objects and replaces
+// them on the fly.
+// TODO: Will heap iteration tolerate this changes-on-iteration?
+// TODO: Do we have to deal with any kind of write barriers here?
+class ReplacingVisitor : public ObjectVisitor {
public:
- explicit ReferenceCollectorVisitor(Code* original)
- : original_(original), rvalues_(10), reloc_infos_(10),
code_entries_(10) {
+ explicit ReplacingVisitor(Code* original, Code* substitution)
+ : original_(original), substitution_(substitution) {
}
virtual void VisitPointers(Object** start, Object** end) {
for (Object** p = start; p < end; p++) {
if (*p == original_) {
- rvalues_.Add(p);
+ *p = substitution_;
}
}
}
virtual void VisitCodeEntry(Address entry) {
if (Code::GetObjectFromEntryAddress(entry) == original_) {
- code_entries_.Add(entry);
+ Address substitution_entry = substitution_->instruction_start();
+ Memory::Address_at(entry) = substitution_entry;
}
}
virtual void VisitCodeTarget(RelocInfo* rinfo) {
if (RelocInfo::IsCodeTarget(rinfo->rmode()) &&
Code::GetCodeFromTargetAddress(rinfo->target_address()) ==
original_) {
- reloc_infos_.Add(*rinfo);
+ Address substitution_entry = substitution_->instruction_start();
+ rinfo->set_target_address(substitution_entry);
}
}
@@ -956,27 +960,9 @@ class ReferenceCollectorVisitor : public ObjectVisitor
{
VisitCodeTarget(rinfo);
}
- // Post-visiting method that iterates over all collected references and
- // modifies them.
- void Replace(Code* substitution) {
- for (int i = 0; i < rvalues_.length(); i++) {
- *(rvalues_[i]) = substitution;
- }
- Address substitution_entry = substitution->instruction_start();
- for (int i = 0; i < reloc_infos_.length(); i++) {
- reloc_infos_[i].set_target_address(substitution_entry);
- }
- for (int i = 0; i < code_entries_.length(); i++) {
- Address entry = code_entries_[i];
- Memory::Address_at(entry) = substitution_entry;
- }
- }
-
private:
Code* original_;
- ZoneList<Object**> rvalues_;
- ZoneList<RelocInfo> reloc_infos_;
- ZoneList<Address> code_entries_;
+ Code* substitution_;
};
@@ -984,28 +970,21 @@ class ReferenceCollectorVisitor : public
ObjectVisitor {
static void ReplaceCodeObject(Code* original, Code* substitution) {
ASSERT(!HEAP->InNewSpace(substitution));
- HeapIterator iterator;
AssertNoAllocation no_allocations_please;
- // A zone scope for ReferenceCollectorVisitor.
- ZoneScope scope(Isolate::Current(), DELETE_ON_EXIT);
-
- ReferenceCollectorVisitor visitor(original);
+ ReplacingVisitor visitor(original, substitution);
// Iterate over all roots. Stack frames may have pointer into original
code,
// so temporary replace the pointers with offset numbers
// in prologue/epilogue.
- {
- HEAP->IterateStrongRoots(&visitor, VISIT_ALL);
- }
+ HEAP->IterateRoots(&visitor, VISIT_ALL);
// Now iterate over all pointers of all objects, including code_target
// implicit pointers.
+ HeapIterator iterator;
for (HeapObject* obj = iterator.next(); obj != NULL; obj =
iterator.next()) {
obj->Iterate(&visitor);
}
-
- visitor.Replace(substitution);
}
--
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