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
to use AddrMode4, there was a count of the registers stored in one of the
operands. I changed that to just count the operands but forgot to adjust for
the size of D registers. This was noticed by Evan as a performance problem
but it is a potential correctness bug as well, since it is possible that this
could merge a base update with a non-matching immediate.
llvm-svn: 113576
cleaning up the output of many GetDescription objects that are part of a
symbol context. This fixes an issue where no ranges were being printed out
for functions, blocks and symbols.
llvm-svn: 113571
take multiple cycles to decode.
For the current if-converter clients (actually only ARM), the instructions that
are predicated on false are not nops. They would still take machine cycles to
decode. Micro-coded instructions such as LDM / STM can potentially take multiple
cycles to decode. If-converter should take treat them as non-micro-coded
simple instructions.
llvm-svn: 113570
is different from what the code now uses in a two ways: NamedMDNodes
were considered Values and included in the numbering, and the
function-local metadata counter wasn't reset between functions.
The later problem breaks lazy deserialization, so instead of trying
to emulate the old numbering, just drop the old metadata. The only
in-tree use case is debug info with LTO, where the QOI loss is
considered acceptable.
llvm-svn: 113557
follows objective's semantics and is not overload'able
with an assignment operator. Fixes a crash and a missing
diagnostics. Radar 8379892.
llvm-svn: 113555
spelled (#pragma, _Pragma, __pragma). In -E mode, use that information
to add appropriate newlines when translating _Pragma and __pragma into
#pragma, like GCC does. Fixes <rdar://problem/8412013>.
llvm-svn: 113553
constructor, in source order. Also introduces a new reference kind for
class members, which is used here (for member initializers) and will
also be used for designated initializers and offsetof.
llvm-svn: 113545
not unrolling loops that contain calls that would be better off getting inlined. This mostly
comes up when an interleaved devirtualization pass has devirtualized a call which the inliner
will inline on a future pass. Thus, rather than blocking all loops containing calls, add
a metric for "inline candidate calls" and block loops containing those instead.
llvm-svn: 113535
to be set up the way they are. Comment out code that removes pending
settings for live instances (after the settings are copied over).
llvm-svn: 113519
Chandler Carruth