module's AST context. Prior to this fix, with gcc binaries, we end up with
a full class definition for any used classes in each compile unit due to the
one definition rule. This would result in us making N copies of class T, where
N is the number of compile units that use class T, in the module AST. When
an expression would then try and use any types that were duplicated, it would
quickly confuse clang and make expression evaluation fail due to all of the
duplicate types that got copied over. This is now fixed by making a map of
types in the DWARF that maps type names to a collection of types + declaration
(file + line number) + DIE. Then later when we find a type we look in this
module map and find any already cached types that we can just use.
8935777
llvm-svn: 125207
to be fed 4 callbacks: read/write memory, and read/write registers. After this,
you can tell the object to read an instruction. This will cause the class to read
the PC, and read and instruction. Then you can emulate the instruction by calling
EvaluateInstruction. This will cause the class to figure out exactly what an opcode
does, and call the read/write mem/regs functions with actual values which allows one
to emulate an instruction without running a process, or it allows one to watch the
context information (the memory write is a pushing register 3 onto the stack at offset
12) so it can be used for generating call frame information. This way, in the future,
we will have one class that can be used to emulate instructions and generate our
unwind info from assembly.
llvm-svn: 123998
bool RegisterContextLLDB::GetPC (addr_t& pc);
to:
bool RegisterContextLLDB::ReadPC (addr_t& pc);
To avoid confusion with the GetPC() function that is part of the
lldb_private::RegisterContext:
uint64_t RegisterContext::GetPC (uint64_t fail_value);
Bad things could happen if the two got intermixed and the wrong one got
called.
Fixed inifinite loop detection by watching for two frames where the
RegisterContextLLDB::CursorSP contains the same start_pc and cfa.
llvm-svn: 123673
a method:
void RegisterContext::InvalidateIfNeeded (bool force);
Each time this function is called, when "force" is false, it will only call
the pure virtual "virtual void RegisterContext::InvalideAllRegisters()" if
the register context's stop ID doesn't match that of the process. When the
stop ID doesn't match, or "force" is true, the base class will clear its
cached registers and the RegisterContext will update its stop ID to match
that of the process. This helps make it easier to correctly flush the register
context (possibly from multiple locations depending on when and where new
registers are availabe) without inadvertently clearing the register cache
when it doesn't need to be.
Modified the ProcessGDBRemote plug-in to be much more efficient when it comes
to:
- caching the expedited registers in the stop reply packets (we were ignoring
these before and it was causing us to read at least three registers every
time we stopped that were already supplied in the stop reply packet).
- When a thread has no stop reason, don't keep asking for the thread stopped
info. Prior to this fix we would continually send a qThreadStopInfo packet
over and over when any thread stop info was requested. We now note the stop
ID that the stop info was requested for and avoid multiple requests.
Cleaned up some of the expression code to not look for ClangExpressionVariable
objects up by name since they are now shared pointers and we can just look for
the exact pointer match and avoid possible errors.
Fixed an bug in the ValueObject code that would cause children to not be
displayed.
llvm-svn: 123127
frames, UnwindLLDB could create the incorrect RegisterContext for a given
stack frame because it was using the frame index (not the concrete frame
index). This was causing crashes when doing backtraces through the
SBFrame::GetFP() because a NULL register context was being returned for the
deepest stack frame.
llvm-svn: 123052
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
cache even when a valid process exists. Previously, Target::ReadMemory would
read from the process if there was a valid one and then fallback to the
object file cache.
llvm-svn: 122989
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
0 mid-stack, stop backtracing.
SectionLoadList.cpp (ResolveLoadAddress): Don't assert on an
out-of-range address, just return an invalid Address object.
The unwinder may be passing in invalid addresses on the final
stack frame and the assert is a problem.
llvm-svn: 122386
RegisterContext* - normally this is retrieved from the ExecutionContext's
StackFrame but when we need to evaluate an expression while creating
the stack frame list this can be a little tricky.
Add DW_OP_deref_size, needed for the _sigtramp FDE expression.
Add support for processing DWARF expressions in RegisterContextLLDB.
Update callers to DWARFExpression::Evaluate.
llvm-svn: 119885
we're using the stack pointer to define the CFA again. Makes unwinds
while sitting at the 'ret' instruction work, assuming we have accurate
function address bounds.
llvm-svn: 119327
needs to use the current pc and current offset in two ways: To
determine which function we are currently executing, and the decide
how much of that function has executed so far. For the former use,
we need to back up the saved pc value by one byte if we're going to
use the correct function's unwind information -- we may be executing
a CALL instruction at the end of a function and the following instruction
belongs to a new function, or we may be looking at unwind information
which only covers the call instruction and not the subsequent instruction.
But when we're talking about deciding which row of an UnwindPlan to
execute, we want to use the actual byte offset in the function, not the
byte offset - 1.
Right now RegisterContextLLDB is tracking both the "real" offset and
an "offset minus one" and different parts of the class have to know
which one to use and they need to be updated/set in tandem. I want
to revisit this at some point.
The second change made in looking up eh_frame information; it was
formerly done by looking for the start address of the function we
are currently executing. But it is possible to have unwind information
for a function which only covers a small section of the function's
address range. In which case looking up by the start pc value may not
find the eh_frame FDE.
The hand-written _sigtramp() unwind info on Mac OS X, which covers
exactly one instruction in the middle of the function, happens to
trigger both of these issues.
I still need to get the UnwindPlan runner to handle arbitrary dwarf
expressions in the FDE but there's a good chance it will be easy to
reuse the DWARFExpression class to do this.
llvm-svn: 118882
I only did a tiny bit of testing; in the one case I tried changing the
contents of a radar in the middle of a stack and it was still current in
the live register context so it filtered down to frame 0 and was handed
over to the live register set RegisterContext. I need to test a case
where a register is saved on the stack in memory before I check this
one off.
llvm-svn: 118486
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
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
Johnny Chen