- When we detect that we're stepping over a function call, also store
the CPU state at the time it occurred. This information is needed
in order to correctly reconstruct target addresses later since some
operands may be register-based.
- Add the aforementioned CPU state to CreateFrame()'s arguments and
adjust implementations and callers accordingly.
- ArchitectureX86 now hands off the work for GetInstructionInfo() to
DisassemblerX86, since the latter has all the information we need
to properly classify and evaluate instructions. Correspondingly a
CpuState is passed down to it in order to perform address calculations
for the instruction if it's a jump or call instruction. The latter's
targets are then stored on the thread for later retrieval when
constructing a stack trace. Adjust X86_64 accordingly for the
signature changes. This also fixes a bug where Step Over would
sometimes result in a Step Into instead due to the previous
implementation of GetInstructionInfo() occasionally failing to
classify call instructions correctly.
- Architecture::CreateStackTrace() now takes an argument specifying
the address of the last executed function if applicable. This is used
to decide who/where to decode a return value from. Adjust callers.
- DwarfImageDebugInfo::_CreateReturnValue() uses the above information
in order to know directly who the caller it needs to look up a return
value for is, rather than trying to walk backwards to find them.
Type resolution is now also a bit more sophisticated due to various
cases where the subprogram entry didn't directly contain the return
type but referred to another DIE that did. Retrieving return value
now appears to work properly in all cases except when position
independent code is involved. The latter however will require
resolving the appropriate function address in the PLT, which will
need some additional work.
- Thread now has a data member indicating if a subroutine was
executed during the last set of steps.
- ThreadHandler now sets the aforementioned state appropriate during
Step Over/Step Out.
- Architecture::CreateStackTrace() now takes a parameter indicating
whether return value retrieval is desired (based on aforementioned
thread value). Adjust callers accordingly.
- DwarfImageDebugInfo: If return value retrieval is requested, loop
backwards from the current IP to find the call instruction.
- CreateStackTrace() now takes a parameter indicating whether or not
to try and retrieve full frame information. This in turn is passed
on to SpecificImageDebugInfo, where e.g. DwarfImageDebugInfo can
use it to avoid constructing variables and parameters. This is
used by ThreadHandler since, when it requests the top frame for
its stepping calculations, this additional data/work is completely
unnecessary.
Rene Gollent