due to RTTI worries since llvm and clang don't use RTTI, but I was able to
switch back with no issues as far as I can tell. Once the RTTI issue wasn't
an issue, we were looking for a way to properly track weak pointers to objects
to solve some of the threading issues we have been running into which naturally
led us back to std::tr1::weak_ptr. We also wanted the ability to make a shared
pointer from just a pointer, which is also easily solved using the
std::tr1::enable_shared_from_this class.
The main reason for this move back is so we can start properly having weak
references to objects. Currently a lldb_private::Thread class has a refrence
to its parent lldb_private::Process. This doesn't work well when we now hand
out a SBThread object that contains a shared pointer to a lldb_private::Thread
as this SBThread can be held onto by external clients and if they end up
using one of these objects we can easily crash.
So the next task is to start adopting std::tr1::weak_ptr where ever it makes
sense which we can do with lldb_private::Debugger, lldb_private::Target,
lldb_private::Process, lldb_private::Thread, lldb_private::StackFrame, and
many more objects now that they are no longer using intrusive ref counted
pointer objects (you can't do std::tr1::weak_ptr functionality with intrusive
pointers).
llvm-svn: 149207
RegisterContextLLDBs it contains.
Previously RegisterContextLLDB objects had a pointer to their "next"
frame down the stack. e.g. stack starts at frame 0; frame 3 has a
pointer to frame 2. This is used to retreive callee saved register
values. When debugging an inferior that has blown out its own stack,
however, this could result in lldb blowing out its own stack while
recursing down to retrieve register values.
RegisterContextLLDB no longer has a pointer to its next frame; it
has a reference to the UnwindLLDB which contains it. When it needs
to retrieve a reg value, it asks the UnwindLLDB for that reg value
and UnwindLLDB iterates through the frames until it finds a location.
llvm-svn: 143423
virtual bool
ABI::StackUsesFrames () = 0;
Should return true if your ABI uses frames when doing stack backtraces. This
means a frame pointer is used that points to the previous stack frame in some
way or another.
virtual bool
ABI::CallFrameAddressIsValid (lldb::addr_t cfa) = 0;
Should take a look at a call frame address (CFA) which is just the stack
pointer value upon entry to a function. ABIs usually impose alignment
restrictions (4, 8 or 16 byte aligned), and zero is usually not allowed.
This function should return true if "cfa" is valid call frame address for
the ABI, and false otherwise. This is used by the generic stack frame unwinding
code to help determine when a stack ends.
virtual bool
ABI::CodeAddressIsValid (lldb::addr_t pc) = 0;
Validates a possible PC value and returns true if an opcode can be at "pc".
Some ABIs or architectures have fixed width instructions and must be aligned
to a 2 or 4 byte boundary. "pc" can be an opcode or a callable address which
means the load address might be decorated with extra bits (such as bit zero
to indicate a thumb function call for ARM targets), so take this into account
when returning true or false. The address should also be validated to ensure
it is a valid address for the address size of the inferior process. 32 bit
targets should make sure the address is less than UINT32_MAX.
Modified UnwindLLDB to use the new ABI functions to help it properly terminate
stacks.
Modified the mach-o function that extracts dependent files to not resolve the
path as the paths inside a binary might not match those on the current
host system.
llvm-svn: 132021
public types and public enums. This was done to keep the SWIG stuff from
parsing all sorts of enums and types that weren't needed, and allows us to
abstract our API better.
llvm-svn: 128239
ArchDefaultUnwindPlan plug-in interfaces are now cached per architecture
instead of being leaked for every frame.
Split the ArchDefaultUnwindPlan_x86 into ArchDefaultUnwindPlan_x86_64 and
ArchDefaultUnwindPlan_i386 interfaces.
There were sporadic crashes that were due to something leaking or being
destroyed when doing stack crawls. This patch should clear up these issues.
llvm-svn: 125541
subclasses will automatically be able to take advantage of caching. The
cache line size is set to 512 by default.
This greatly speeds up stack backtraces on MacOSX when using the
ProcessGDBRemote process plug-in since only about 6300 packets per second
can be sent.
Initial speedups show:
Prior to caching: 10,000 stack frames took 5.2 seconds
After caching: 10,000 stack frames in 240 ms!
About a 20x speedup!
llvm-svn: 122996
an issue with the way the UnwindLLDB was handing out RegisterContexts: it
was making shared pointers to register contexts and then handing out just
the pointers (which would get put into shared pointers in the thread and
stack frame classes) and cause double free issues. MallocScribble helped to
find these issues after I did some other cleanup. To help avoid any
RegisterContext issue in the future, all code that deals with them now
returns shared pointers to the register contexts so we don't end up with
multiple deletions. Also now that the RegisterContext class doesn't require
a stack frame, we patched a memory leak where a StackFrame object was being
created and leaked.
Made the RegisterContext class not have a pointer to a StackFrame object as
one register context class can be used for N inlined stack frames so there is
not a 1 - 1 mapping. Updates the ExecutionContextScope part of the
RegisterContext class to never return a stack frame to indicate this when it
is asked to recreate the execution context. Now register contexts point to the
concrete frame using a concrete frame index. Concrete frames are all of the
frames that are actually formed on the stack of a thread. These concrete frames
can be turned into one or more user visible frames due to inlining. Each
inlined stack frame has the exact same register context (shared via shared
pointers) as any parent inlined stack frames all the way up to the concrete
frame itself.
So now the stack frames and the register contexts should behave much better.
llvm-svn: 122976
the frame count is requested or each frame is individually requested.
In practice this doesn't seem to help anything because we have
functions like StackFrameList::GetNumFrames() which is going to
request each frame anyway. And classes like ThreadPlanStepRange
and ThreadPlanStepOverRange get the stack depth in their ctor forcing
a full stack walk. But at least UnwindLLDB will delay doing a full
walk if it can.
llvm-svn: 118477
FuncUnwinders object if the eh_frame section was missing
from an objfile. Worked fine on x86_64 but on i386 where
eh_frame is unusual, that resulted in the arch default
UnwindPlan being used all the time instead of picking up
an assembly profile based unwindplan.
llvm-svn: 118467
fixed them. Added DISALLOW_COPY_AND_ASSIGN to classes that should
not be bitwise copied. Added default initializers for member
variables that weren't being initialized in the ctor. Fixed a few
shadowed local variable mistakes.
llvm-svn: 118240
RegisterContextLLDB holds a reference to the SymbolContext
in the vector of Cursors that UnwindLLDB maintains. Switch
UnwindLLDB to hold a vector of shared pointers of Cursors
so this reference doesn't become invalid.
Correctly falling back from the "fast" UnwindPlan to the
"full" UnwindPlan when additional registers need to be
retrieved.
llvm-svn: 118218
Not yet enabled as the default unwinder but there are no known
backtrace problems with the code at this point.
Added 'log enable lldb unwind' to help diagnose backtrace problems;
this output needs a little refining but it's a good first step.
eh_frame information is currently read unconditionally - the code
is structured to allow this to be delayed until it's actually needed.
There is a performance hit when you have to parse the eh_frame
information for any largeish executable/library so it's necessary
to avoid if possible.
It's confusing having both the UnwindPlan::RegisterLocation struct
and the RegisterConextLLDB::RegisterLocation struct, I need to rename
one of them.
The writing of registers isn't done in the RegisterConextLLDB subclass
yet; neither is the running of complex DWARF expressions from eh_frame
(e.g. used for _sigtramp on Mac OS X).
llvm-svn: 117256
Greg Clayton