maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

<rdar://problem/15593026> 

Fix the algorithm used to detect a loop in a std::list

llvm-svn: 202205
This commit is contained in:
Enrico Granata 2014-02-25 23:34:40 +00:00
parent 339430f993
commit c6f0a6ac27
1 changed files with 30 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
lldb/source/DataFormatters/LibCxxList.cpp
View File

@ -33,20 +33,20 @@ public:
ListEntry (const ListEntry& rhs) : m_entry_sp(rhs.m_entry_sp) {}
ListEntry (ValueObject* entry) : m_entry_sp(entry ? entry->GetSP() : ValueObjectSP()) {}
ValueObjectSP
ListEntry
next ()
{
if (!m_entry_sp)
return m_entry_sp;
return m_entry_sp->GetChildMemberWithName(ConstString("__next_"), true);
return ListEntry();
return ListEntry(m_entry_sp->GetChildMemberWithName(ConstString("__next_"), true));
}
ValueObjectSP
ListEntry
prev ()
{
if (!m_entry_sp)
return m_entry_sp;
return m_entry_sp->GetChildMemberWithName(ConstString("__prev_"), true);
return ListEntry();
return ListEntry(m_entry_sp->GetChildMemberWithName(ConstString("__prev_"), true));
}
uint64_t
@ -63,6 +63,11 @@ public:
return (value() == 0);
}
explicit operator bool ()
{
return GetEntry().get() != nullptr && null() == false;
}
ValueObjectSP
GetEntry ()
{
@ -130,13 +135,13 @@ protected:
void
next ()
{
m_entry.SetEntry(m_entry.next());
m_entry = m_entry.next();
}
void
prev ()
{
m_entry.SetEntry(m_entry.prev());
m_entry = m_entry.prev();
}
private:
ListEntry m_entry;
@ -161,17 +166,24 @@ lldb_private::formatters::LibcxxStdListSyntheticFrontEnd::HasLoop()
{
if (g_use_loop_detect == false)
return false;
// don't bother checking for a loop if we won't actually need to jump nodes
if (m_count < 2)
return false;
auto steps_left = m_count;
ListEntry slow(m_head);
ListEntry fast1(m_head);
ListEntry fast2(m_head);
while (slow.next() && slow.next()->GetValueAsUnsigned(0) != m_node_address)
ListEntry fast(m_head);
while (steps_left-- > 0)
{
auto slow_value = slow.value();
fast1.SetEntry(fast2.next());
fast2.SetEntry(fast1.next());
if (fast1.value() == slow_value || fast2.value() == slow_value)
slow = slow.next();
fast = fast.next();
if (fast.next())
fast = fast.next().next();
else
fast = nullptr;
if (!slow || !fast)
return false;
if (slow == fast)
return true;
slow.SetEntry(slow.next());
}
return false;
}
@ -212,10 +224,10 @@ lldb_private::formatters::LibcxxStdListSyntheticFrontEnd::CalculateNumChildren (
return 0;
uint64_t size = 2;
ListEntry current(m_head);
while (current.next() && current.next()->GetValueAsUnsigned(0) != m_node_address)
while (current.next() && current.next().value() != m_node_address)
{
size++;
current.SetEntry(current.next());
current = current.next();
if (size > m_list_capping_size)
break;
}