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Add a function to make a mutex-protected copy of a breakpoint site's 

owners list, so the StopInfo machinery can get the list of owners without
some other thread being able to mess up the list by deleting/disabline one of its
locations in the process of doing so.

<rdar://problem/18685197>

llvm-svn: 243541
This commit is contained in:
Jim Ingham 2015-07-29 17:51:36 +00:00
parent 38c0250679
commit 9d1ccdaf7e
3 changed files with 31 additions and 7 deletions
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14
lldb/include/lldb/Breakpoint/BreakpointSite.h
View File

@ -186,6 +186,20 @@ public:
lldb::BreakpointLocationSP
GetOwnerAtIndex (size_t idx);
//------------------------------------------------------------------
/// This method copies the breakpoint site's owners into a new collection.
/// It does this while the owners mutex is locked.
///
/// @param[out] out_collection
/// The BreakpointLocationCollection into which to put the owners
/// of this breakpoint site.
///
/// @return
/// The number of elements copied into out_collection.
//------------------------------------------------------------------
size_t
CopyOwnersList (BreakpointLocationCollection &out_collection);
//------------------------------------------------------------------
/// Check whether the owners of this breakpoint site have any
/// thread specifiers, and if yes, is \a thread contained in any

11
lldb/source/Breakpoint/BreakpointSite.cpp
View File

@ -254,3 +254,14 @@ BreakpointSite::IntersectsRange(lldb::addr_t addr, size_t size, lldb::addr_t *in
}
return false;
}
size_t
BreakpointSite::CopyOwnersList (BreakpointLocationCollection &out_collection)
{
Mutex::Locker locker(m_owners_mutex);
for (BreakpointLocationSP loc_sp : m_owners.BreakpointLocations())
{
out_collection.Add(loc_sp);
}
return out_collection.GetSize();
}

13
lldb/source/Target/StopInfo.cpp
View File

@ -350,7 +350,10 @@ protected:
if (bp_site_sp)
{
size_t num_owners = bp_site_sp->GetNumberOfOwners();
// Let's copy the owners list out of the site and store them in a local list. That way if
// one of the breakpoint actions changes the site, then we won't be operating on a bad list.
BreakpointLocationCollection site_locations;
size_t num_owners = bp_site_sp->CopyOwnersList(site_locations);
if (num_owners == 0)
{
@ -416,20 +419,16 @@ protected:
StoppointCallbackContext context (event_ptr, exe_ctx, false);
// Let's copy the breakpoint locations out of the site and store them in a local list. That way if
// one of the breakpoint actions changes the site, then we won't be operating on a bad list.
// For safety's sake let's also grab an extra reference to the breakpoint owners of the locations we're
// going to examine, since the locations are going to have to get back to their breakpoints, and the
// locations don't keep their owners alive. I'm just sticking the BreakpointSP's in a vector since
// I'm only really using it to locally increment their retain counts.
// I'm only using it to locally increment their retain counts.
BreakpointLocationCollection site_locations;
std::vector<lldb::BreakpointSP> location_owners;
for (size_t j = 0; j < num_owners; j++)
{
BreakpointLocationSP loc(bp_site_sp->GetOwnerAtIndex(j));
site_locations.Add(loc);
BreakpointLocationSP loc(site_locations.GetByIndex(j));
location_owners.push_back(loc->GetBreakpoint().shared_from_this());
}