AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

Refactored PathTracer in heap.cc.

Browse Source 
This is so that it can be reused by LOL code later.

Patch by Mark Lam from Hewlett-Packard Development Company, LP

Review URL: http://codereview.chromium.org/6541044


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6886 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
sgjesse@chromium.org 2011-02-22 10:05:30 +00:00
parent 2ab5691ac1
commit b0fa94777e
2 changed files with 164 additions and 82 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

185
src/heap.cc
View File

@ -5181,32 +5181,77 @@ void HeapIterator::reset() {
}
#ifdef DEBUG
#if defined(DEBUG) || defined(LIVE_OBJECT_LIST)
static bool search_for_any_global;
static Object* search_target;
static bool found_target;
static List<Object*> object_stack(20);
Object* const PathTracer::kAnyGlobalObject = reinterpret_cast<Object*>(NULL);
// Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
static const int kMarkTag = 2;
static void MarkObjectRecursively(Object** p);
class MarkObjectVisitor : public ObjectVisitor {
class PathTracer::MarkVisitor: public ObjectVisitor {
public:
explicit MarkVisitor(PathTracer* tracer) : tracer_(tracer) {}
void VisitPointers(Object** start, Object** end) {
// Copy all HeapObject pointers in [start, end)
for (Object** p = start; p < end; p++) {
// Scan all HeapObject pointers in [start, end)
for (Object** p = start; !tracer_->found() && (p < end); p++) {
if ((*p)->IsHeapObject())
MarkObjectRecursively(p);
tracer_->MarkRecursively(p, this);
}
}
private:
PathTracer* tracer_;
};
static MarkObjectVisitor mark_visitor;
static void MarkObjectRecursively(Object** p) {
class PathTracer::UnmarkVisitor: public ObjectVisitor {
public:
explicit UnmarkVisitor(PathTracer* tracer) : tracer_(tracer) {}
void VisitPointers(Object** start, Object** end) {
// Scan all HeapObject pointers in [start, end)
for (Object** p = start; p < end; p++) {
if ((*p)->IsHeapObject())
tracer_->UnmarkRecursively(p, this);
}
}
private:
PathTracer* tracer_;
};
void PathTracer::VisitPointers(Object** start, Object** end) {
bool done = ((what_to_find_ == FIND_FIRST) && found_target_);
// Visit all HeapObject pointers in [start, end)
for (Object** p = start; !done && (p < end); p++) {
if ((*p)->IsHeapObject()) {
TracePathFrom(p);
done = ((what_to_find_ == FIND_FIRST) && found_target_);
}
}
}
void PathTracer::Reset() {
found_target_ = false;
object_stack_.Clear();
}
void PathTracer::TracePathFrom(Object** root) {
ASSERT((search_target_ == kAnyGlobalObject) ||
search_target_->IsHeapObject());
found_target_in_trace_ = false;
object_stack_.Clear();
MarkVisitor mark_visitor(this);
MarkRecursively(root, &mark_visitor);
UnmarkVisitor unmark_visitor(this);
UnmarkRecursively(root, &unmark_visitor);
ProcessResults();
}
void PathTracer::MarkRecursively(Object** p, MarkVisitor* mark_visitor) {
if (!(*p)->IsHeapObject()) return;
HeapObject* obj = HeapObject::cast(*p);
@ -5215,14 +5260,17 @@ static void MarkObjectRecursively(Object** p) {
if (!map->IsHeapObject()) return; // visited before
if (found_target) return; // stop if target found
object_stack.Add(obj);
if ((search_for_any_global && obj->IsJSGlobalObject()) ||
(!search_for_any_global && (obj == search_target))) {
found_target = true;
if (found_target_in_trace_) return; // stop if target found
object_stack_.Add(obj);
if (((search_target_ == kAnyGlobalObject) && obj->IsJSGlobalObject()) ||
(obj == search_target_)) {
found_target_in_trace_ = true;
found_target_ = true;
return;
}
bool is_global_context = obj->IsGlobalContext();
// not visited yet
Map* map_p = reinterpret_cast<Map*>(HeapObject::cast(map));
@ -5230,31 +5278,30 @@ static void MarkObjectRecursively(Object** p) {
obj->set_map(reinterpret_cast<Map*>(map_addr + kMarkTag));
MarkObjectRecursively(&map);
// Scan the object body.
if (is_global_context && (visit_mode_ == VISIT_ONLY_STRONG)) {
// This is specialized to scan Context's properly.
Object** start = reinterpret_cast<Object**>(obj->address() +
Context::kHeaderSize);
Object** end = reinterpret_cast<Object**>(obj->address() +
Context::kHeaderSize + Context::FIRST_WEAK_SLOT * kPointerSize);
mark_visitor->VisitPointers(start, end);
} else {
obj->IterateBody(map_p->instance_type(),
obj->SizeFromMap(map_p),
mark_visitor);
}
obj->IterateBody(map_p->instance_type(), obj->SizeFromMap(map_p),
&mark_visitor);
// Scan the map after the body because the body is a lot more interesting
// when doing leak detection.
MarkRecursively(&map, mark_visitor);
if (!found_target) // don't pop if found the target
object_stack.RemoveLast();
if (!found_target_in_trace_) // don't pop if found the target
object_stack_.RemoveLast();
}
static void UnmarkObjectRecursively(Object** p);
class UnmarkObjectVisitor : public ObjectVisitor {
public:
void VisitPointers(Object** start, Object** end) {
// Copy all HeapObject pointers in [start, end)
for (Object** p = start; p < end; p++) {
if ((*p)->IsHeapObject())
UnmarkObjectRecursively(p);
}
}
};
static UnmarkObjectVisitor unmark_visitor;
static void UnmarkObjectRecursively(Object** p) {
void PathTracer::UnmarkRecursively(Object** p, UnmarkVisitor* unmark_visitor) {
if (!(*p)->IsHeapObject()) return;
HeapObject* obj = HeapObject::cast(*p);
@ -5273,63 +5320,38 @@ static void UnmarkObjectRecursively(Object** p) {
obj->set_map(reinterpret_cast<Map*>(map_p));
UnmarkObjectRecursively(reinterpret_cast<Object**>(&map_p));
UnmarkRecursively(reinterpret_cast<Object**>(&map_p), unmark_visitor);
obj->IterateBody(Map::cast(map_p)->instance_type(),
obj->SizeFromMap(Map::cast(map_p)),
&unmark_visitor);
unmark_visitor);
}
static void MarkRootObjectRecursively(Object** root) {
if (search_for_any_global) {
ASSERT(search_target == NULL);
} else {
ASSERT(search_target->IsHeapObject());
}
found_target = false;
object_stack.Clear();
MarkObjectRecursively(root);
UnmarkObjectRecursively(root);
if (found_target) {
void PathTracer::ProcessResults() {
if (found_target_) {
PrintF("=====================================\n");
PrintF("==== Path to object ====\n");
PrintF("=====================================\n\n");
ASSERT(!object_stack.is_empty());
for (int i = 0; i < object_stack.length(); i++) {
ASSERT(!object_stack_.is_empty());
for (int i = 0; i < object_stack_.length(); i++) {
if (i > 0) PrintF("\n |\n |\n V\n\n");
Object* obj = object_stack[i];
Object* obj = object_stack_[i];
obj->Print();
}
PrintF("=====================================\n");
}
}
#endif // DEBUG || LIVE_OBJECT_LIST
// Helper class for visiting HeapObjects recursively.
class MarkRootVisitor: public ObjectVisitor {
public:
void VisitPointers(Object** start, Object** end) {
// Visit all HeapObject pointers in [start, end)
for (Object** p = start; p < end; p++) {
if ((*p)->IsHeapObject())
MarkRootObjectRecursively(p);
}
}
};
#ifdef DEBUG
// Triggers a depth-first traversal of reachable objects from roots
// and finds a path to a specific heap object and prints it.
void Heap::TracePathToObject(Object* target) {
search_target = target;
search_for_any_global = false;
MarkRootVisitor root_visitor;
IterateRoots(&root_visitor, VISIT_ONLY_STRONG);
PathTracer tracer(target, PathTracer::FIND_ALL, VISIT_ALL);
IterateRoots(&tracer, VISIT_ONLY_STRONG);
}
@ -5337,11 +5359,10 @@ void Heap::TracePathToObject(Object* target) {
// and finds a path to any global object and prints it. Useful for
// determining the source for leaks of global objects.
void Heap::TracePathToGlobal() {
search_target = NULL;
search_for_any_global = true;
MarkRootVisitor root_visitor;
IterateRoots(&root_visitor, VISIT_ONLY_STRONG);
PathTracer tracer(PathTracer::kAnyGlobalObject,
PathTracer::FIND_ALL,
VISIT_ALL);
IterateRoots(&tracer, VISIT_ONLY_STRONG);
}
#endif

61
src/heap.h
View File

@ -30,6 +30,8 @@
#include <math.h>
#include "globals.h"
#include "list.h"
#include "spaces.h"
#include "splay-tree-inl.h"
#include "v8-counters.h"
@ -2152,6 +2154,65 @@ class WeakObjectRetainer {
};
#if defined(DEBUG) || defined(LIVE_OBJECT_LIST)
// Helper class for tracing paths to a search target Object from all roots.
// The TracePathFrom() method can be used to trace paths from a specific
// object to the search target object.
class PathTracer : public ObjectVisitor {
public:
enum WhatToFind {
FIND_ALL, // Will find all matches.
FIND_FIRST // Will stop the search after first match.
};
// For the WhatToFind arg, if FIND_FIRST is specified, tracing will stop
// after the first match. If FIND_ALL is specified, then tracing will be
// done for all matches.
PathTracer(Object* search_target,
WhatToFind what_to_find,
VisitMode visit_mode)
: search_target_(search_target),
found_target_(false),
found_target_in_trace_(false),
what_to_find_(what_to_find),
visit_mode_(visit_mode),
object_stack_(20),
no_alloc() {}
virtual void VisitPointers(Object** start, Object** end);
void Reset();
void TracePathFrom(Object** root);
bool found() const { return found_target_; }
static Object* const kAnyGlobalObject;
protected:
class MarkVisitor;
class UnmarkVisitor;
void MarkRecursively(Object** p, MarkVisitor* mark_visitor);
void UnmarkRecursively(Object** p, UnmarkVisitor* unmark_visitor);
virtual void ProcessResults();
// Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
static const int kMarkTag = 2;
Object* search_target_;
bool found_target_;
bool found_target_in_trace_;
WhatToFind what_to_find_;
VisitMode visit_mode_;
List<Object*> object_stack_;
AssertNoAllocation no_alloc; // i.e. no gc allowed.
DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
};
#endif // DEBUG || LIVE_OBJECT_LIST
} } // namespace v8::internal
#endif // V8_HEAP_H_