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
don't crash if we disable logging when some code already has a copy of the
logger. Prior to this fix, logs were handed out as pointers and if they were
held onto while a log got disabled, then it could cause a crash. Now all logs
are handed out as shared pointers so this problem shouldn't happen anymore.
We are also using our new shared pointers that put the shared pointer count
and the object into the same allocation for a tad better performance.
llvm-svn: 118319
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
loaded/parsed. Should add timers to this eventually.
Delay getting a full UnwindPlan if it's possible to unwind with
just a fast UnwindPlan. This keeps us from reading the eh_frame
section unless we hit something built -fomit-frame pointer or we
hit a frame with no symbol (read: no start address) available.
It doesn't look like it is correctly falling back to using the
full UnwindPlan to provide additional registers that the fast
UnwindPlan doesn't supply; e.g. go to the middle of a stack and
ask for r12 and it will show you the value of r12 in frame 0.
That's a bug for tomorrow.
llvm-svn: 117361
gets to be a problem if you have a unbounded stack walk.
Fix the CFA sanity checks. Add one to the arch default UnwindPlan run which was giving
one extra stack frame on the main thread. Fix a couple of logging lines that had their
argument order incorrect.
llvm-svn: 117350
prologue profiling.
Change the log print statements to elide the thread number, make
some of them only print when IsLogVerbose().
Add a couple of sanity checks for impossible CFA values so backtraces
don't go too far off into the weeds.
llvm-svn: 117343
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
whether a given register number is treated as volatile
or not for a given architecture/platform.
approx 450 lines of boilerplate, 50 lines of actual code. :)
llvm-svn: 114537
The Unwind and RegisterContext subclasses still need
to be finished; none of this code is used by lldb at
this point (unless you call into it by hand).
The ObjectFile class now has an UnwindTable object.
The UnwindTable object has a series of FuncUnwinders
objects (Function Unwinders) -- one for each function
in that ObjectFile we've backtraced through during this
debug session.
The FuncUnwinders object has a few different UnwindPlans.
UnwindPlans are a generic way of describing how to find
the canonical address of a given function's stack frame
(the CFA idea from DWARF/eh_frame) and how to restore the
caller frame's register values, if they have been saved
by this function.
UnwindPlans are created from different sources. One source is the
eh_frame exception handling information generated by the compiler
for unwinding an exception throw. Another source is an assembly
language inspection class (UnwindAssemblyProfiler, uses the Plugin
architecture) which looks at the instructions in the funciton
prologue and describes the stack movements/register saves that are
done.
Two additional types of UnwindPlans that are worth noting are
the "fast" stack UnwindPlan which is useful for making a first
pass over a thread's stack, determining how many stack frames there
are and retrieving the pc and CFA values for each frame (enough
to create StackFrameIDs). Only a minimal set of registers is
recovered during a fast stack walk.
The final UnwindPlan is an architectural default unwind plan.
These are provided by the ArchDefaultUnwindPlan class (which uses
the plugin architecture). When no symbol/function address range can
be found for a given pc value -- when we have no eh_frame information
and when we don't have a start address so we can't examine the assembly
language instrucitons -- we have to make a best guess about how to
unwind. That's when we use the architectural default UnwindPlan.
On x86_64, this would be to assume that rbp is used as a stack pointer
and we can use that to find the caller's frame pointer and pc value.
It's a last-ditch best guess about how to unwind out of a frame.
There are heuristics about when to use one UnwindPlan versues the other --
this will all happen in the still-begin-written UnwindLLDB subclass of
Unwind which runs the UnwindPlans.
llvm-svn: 113581
documentation. Symbol now inherits from the symbol
context scope so that the StackID can use a "SymbolContextScope *"
instead of a blockID (which could have been the same as some other
blockID from another symbol file).
Modified the stacks that are created on subsequent stops to reuse
the previous stack frame objects which will allow for some internal
optimization using pointer comparisons during stepping.
llvm-svn: 112495
complex inlined examples.
StackFrame classes don't have a "GetPC" anymore, they have "GetFrameCodeAddress()".
This is because inlined frames will have a PC value that is the same as the
concrete frame that owns the inlined frame, yet the code locations for the
frame can be different. We also need to be able to get the real PC value for
a given frame so that variables evaluate correctly. To get the actual PC
value for a frame you can use:
addr_t pc = frame->GetRegisterContext()->GetPC();
Some issues with the StackFrame stomping on its own symbol context were
resolved which were causing the information to change for a frame when the
stack ID was calculated. Also the StackFrame will now correctly store the
symbol context resolve flags for any extra bits of information that were
looked up (if you ask for a block only and you find one, you will alwasy have
the compile unit and function).
llvm-svn: 111964
which is now on by default. Frames are gotten from the unwinder as concrete
frames, then if inline frames are to be shown, extra information to track
and reconstruct these frames is cached with each Thread and exanded as needed.
I added an inline height as part of the lldb_private::StackID class, the class
that helps us uniquely identify stack frames. This allows for two frames to
shared the same call frame address, yet differ only in inline height.
Fixed setting breakpoint by address to not require addresses to resolve.
A quick example:
% cat main.cpp
% ./build/Debug/lldb test/stl/a.out
Current executable set to 'test/stl/a.out' (x86_64).
(lldb) breakpoint set --address 0x0000000100000d31
Breakpoint created: 1: address = 0x0000000100000d31, locations = 1
(lldb) r
Launching 'a.out' (x86_64)
(lldb) Process 38031 Stopped
* thread #1: tid = 0x2e03, pc = 0x0000000100000d31, where = a.out`main [inlined] std::string::_M_data() const at /usr/include/c++/4.2.1/bits/basic_string.h:280, stop reason = breakpoint 1.1, queue = com.apple.main-thread
277
278 _CharT*
279 _M_data() const
280 -> { return _M_dataplus._M_p; }
281
282 _CharT*
283 _M_data(_CharT* __p)
(lldb) bt
thread #1: tid = 0x2e03, stop reason = breakpoint 1.1, queue = com.apple.main-thread
frame #0: pc = 0x0000000100000d31, where = a.out`main [inlined] std::string::_M_data() const at /usr/include/c++/4.2.1/bits/basic_string.h:280
frame #1: pc = 0x0000000100000d31, where = a.out`main [inlined] std::string::_M_rep() const at /usr/include/c++/4.2.1/bits/basic_string.h:288
frame #2: pc = 0x0000000100000d31, where = a.out`main [inlined] std::string::size() const at /usr/include/c++/4.2.1/bits/basic_string.h:606
frame #3: pc = 0x0000000100000d31, where = a.out`main [inlined] operator<< <char, std::char_traits<char>, std::allocator<char> > at /usr/include/c++/4.2.1/bits/basic_string.h:2414
frame #4: pc = 0x0000000100000d31, where = a.out`main + 33 at /Volumes/work/gclayton/Documents/src/lldb/test/stl/main.cpp:14
frame #5: pc = 0x0000000100000d08, where = a.out`start + 52
Each inline frame contains only the variables that they contain and each inlined
stack frame is treated as a single entity.
llvm-svn: 111877
This will allow debugger plug-ins to make any instance of "lldb_private::StopInfo"
that can completely describe any stop reason. It also provides a framework for
doing intelligent things with the stop info at important times in the lifetime
of the inferior.
Examples include the signal stop info in StopInfoUnixSignal. It will check with
the process to see that the current action is for the signal. These actions
include wether to stop for the signal, wether the notify that the signal was
hit, and wether to pass the signal along to the inferior process. The
StopInfoUnixSignal class overrides the "ShouldStop()" method of StopInfo and
this allows the stop info to determine if it should stop at the signal or
continue the process.
StopInfo subclasses must override the following functions:
virtual lldb::StopReason
GetStopReason () const = 0;
virtual const char *
GetDescription () = 0;
StopInfo subclasses can override the following functions:
// If the subclass returns "false", the inferior will resume. The default
// version of this function returns "true" which means the default stop
// info will stop the process. The breakpoint subclass will check if
// the breakpoint wants us to stop by calling any installed callback on
// the breakpoint, and also checking if the breakpoint is for the current
// thread. Signals will check if they should stop based off of the
// UnixSignal settings in the process.
virtual bool
ShouldStop (Event *event_ptr);
// Sublasses can state if they want to notify the debugger when "ShouldStop"
// returns false. This would be handy for breakpoints where you want to
// log information and continue and is also used by the signal stop info
// to notify that a signal was received (after it checks with the process
// signal settings).
virtual bool
ShouldNotify (Event *event_ptr)
{
return false;
}
// Allow subclasses to do something intelligent right before we resume.
// The signal class will figure out if the signal should be propagated
// to the inferior process and pass that along to the debugger plug-ins.
virtual void
WillResume (lldb::StateType resume_state)
{
// By default, don't do anything
}
The support the Mach exceptions was moved into the lldb/source/Plugins/Process/Utility
folder and now doesn't polute the lldb_private::Thread class with platform
specific code.
llvm-svn: 110184
enabled LLVM make style building and made this compile LLDB on Mac OS X. We
can now iterate on this to make the build work on both linux and macosx.
llvm-svn: 108009
type and sub-type, or an ELF e_machine value. Also added a generic CPU type
to the arch spec class so we can have a single arch definition that the LLDB
core code can use. Previously a lot of places in the code were using the
mach-o definitions from a macosx header file.
Switches over to using "llvm/Support/MachO.h" for the llvm::MachO::XXX for the
CPU types and sub types for mach-o ArchSpecs. Added "llvm/Support/ELF.h" so
we can use the "llvm::ELF::XXX" defines for the ELF ArchSpecs.
Got rid of all CPU_TYPE_ and CPU_SUBTYPE_ defines that were previously being
used in LLDB.
llvm-svn: 105806
Jason Molenda