if this is a mapped/executable region of memory. If it isn't, we've jumped
through a bad pointer and we know how to unwind the stack correctly based
on the ABI.
Previously I had 0x0 special cased but if you jumped to 0x2 on x86_64 one
frame would be skipped because the unwinder would try using the x86_64
ArchDefaultUnwindPlan which relied on the rbp.
Fixes <rdar://problem/10508291>
llvm-svn: 146477
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
with the same CFA (or an alternating sequence between two CFA values) to catch a handful of
unwind cases where lldb will inf loop trying to unwind a stack.
llvm-svn: 142331
the arm emulate instruction unwinder so you can leave it
on by default and not be overwhelmed. Set verbose mode to
get the full story on how the unwindplans were created.
llvm-svn: 139897
UnwindPlan for unwinding from the first instruction of an otherwise
unknown function call (GetUnwindPlanArchitectureDefaultAtFunctionEntry()).
Update RegisterContextLLDB::GetFullUnwindPlanForFrame() to detect the
case of a frame 0 at address 0x0 which indicates that we jumped through
a NULL function pointer. Use the ABI's FunctionEntryUnwindPlan to
find the caller frame.
These changes make it so lldb can identify the calling frame correctly
in code like
int main ()
{
void (*f)(void) = 0;
f();
}
llvm-svn: 139760
register names when dumping variable locations and location lists. Also did
some cleanup where "int" types were being used for "lldb::RegisterKind"
values.
llvm-svn: 138988
darwin (not sure about other platforms).
Modified the communication and connection classes to not require the
BytesAvailable function. Now the "Read(...)" function has a timeout in
microseconds.
Fixed a lot of assertions that were firing off in certain cases and replaced
them with error output and code that can deal with the assertion case.
llvm-svn: 133224
respective ABI plugins as they were plug-ins that supplied ABI specfic info.
Also hookep up the UnwindAssemblyInstEmulation so that it can generate the
unwind plans for ARM.
Changed the way ABI plug-ins are handed out when you get an instance from
the plug-in manager. They used to return pointers that would be mananged
individually by each client that requested them, but now they are handed out
as shared pointers since there is no state in the ABI objects, they can be
shared.
llvm-svn: 131193
into some cleanup I have been wanting to do when reading/writing registers.
Previously all RegisterContext subclasses would need to implement:
virtual bool
ReadRegisterBytes (uint32_t reg, DataExtractor &data);
virtual bool
WriteRegisterBytes (uint32_t reg, DataExtractor &data, uint32_t data_offset = 0);
There is now a new class specifically designed to hold register values:
lldb_private::RegisterValue
The new register context calls that subclasses must implement are:
virtual bool
ReadRegister (const RegisterInfo *reg_info, RegisterValue ®_value) = 0;
virtual bool
WriteRegister (const RegisterInfo *reg_info, const RegisterValue ®_value) = 0;
The RegisterValue class must be big enough to handle any register value. The
class contains an enumeration for the value type, and then a union for the
data value. Any integer/float values are stored directly in an appropriate
host integer/float. Anything bigger is stored in a byte buffer that has a length
and byte order. The RegisterValue class also knows how to copy register value
bytes into in a buffer with a specified byte order which can be used to write
the register value down into memory, and this does the right thing when not
all bytes from the register values are needed (getting a uint8 from a uint32
register value..).
All RegiterContext and other sources have been switched over to using the new
regiter value class.
llvm-svn: 131096
inline contexts when the deepest most block is not inlined.
Added source path remappings to the lldb_private::Target class that allow it
to remap paths found in debug info so we can find source files that are elsewhere
on the current system.
Fixed disassembly by function name to disassemble inline functions that are
inside other functions much better and to show enough context before the
disassembly output so you can tell where things came from.
Added the ability to get more than one address range from a SymbolContext
class for the case where a block or function has discontiguous address ranges.
llvm-svn: 130044
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
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
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
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
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
Jason Molenda