[Lldb-commits] [lldb] r252963 - Another little stepping optimization: if any of the source step commands are running through a range

Thu Nov 12 15:52:29 PST 2015

Hi Jim,

This breaks about 12 tests on Windows.  The patch looks simple, but this
isn't really my area, is there anything I can give you to help diagnose
what might be wrong?  The following tests fail:

FAIL: LLDB (suite) :: Test-rdar-9974002.py (Windows zturner-win81 8
6.2.9200 AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestDataFormatterHexCaps.py (Windows zturner-win81 8
6.2.9200 AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestDataFormatterNamedSummaries.py (Windows
zturner-win81 8 6.2.9200 AMD64 Intel64 Family 6 Model 45 Stepping 7,
GenuineIntel)
FAIL: LLDB (suite) :: TestDataFormatterPythonSynth.py (Windows
zturner-win81 8 6.2.9200 AMD64 Intel64 Family 6 Model 45 Stepping 7,
GenuineIntel)
FAIL: LLDB (suite) :: TestDataFormatterSynth.py (Windows zturner-win81 8
6.2.9200 AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestDiamond.py (Windows zturner-win81 8 6.2.9200
AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestFormatPropagation.py (Windows zturner-win81 8
6.2.9200 AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestFrames.py (Windows zturner-win81 8 6.2.9200 AMD64
Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestInlineStepping.py (Windows zturner-win81 8
6.2.9200 AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestSBData.py (Windows zturner-win81 8 6.2.9200 AMD64
Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestStepNoDebug.py (Windows zturner-win81 8 6.2.9200
AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)
FAIL: LLDB (suite) :: TestThreadJump.py (Windows zturner-win81 8 6.2.9200
AMD64 Intel64 Family 6 Model 45 Stepping 7, GenuineIntel)

And here's the error I get from one of the failing tests, although I don't
know how much insight it provides.

Traceback (most recent call last):
  File "D:\src\llvm\tools\lldb\packages\Python\lldbsuite\test\lldbtest.py",
line 536, in wrapper
    return func(self, *args, **kwargs)
  File "D:\src\llvm\tools\lldb\packages\Python\lldbsuite\test\lldbtest.py",
line 2228, in dwarf_test_method
    return attrvalue(self)
  File "D:\src\llvm\tools\lldb\packages\Python\lldbsuite\test\lldbtest.py",
line 608, in wrapper
    func(*args, **kwargs)
  File
"D:\src\llvm\tools\lldb\packages\Python\lldbsuite\test\functionalities\step-avoids-no-debug\TestStepNoDebug.py",
line 41, in test_step_in_with_python
    self.do_step_in_past_nodebug()
  File
"D:\src\llvm\tools\lldb\packages\Python\lldbsuite\test\functionalities\step-avoids-no-debug\TestStepNoDebug.py",
line 105, in do_step_in_past_nodebug
    self.hit_correct_line ("intermediate_return_value =
called_from_nodebug_actual(some_value)")
  File
"D:\src\llvm\tools\lldb\packages\Python\lldbsuite\test\functionalities\step-avoids-no-debug\TestStepNoDebug.py",
line 57, in hit_correct_line
    self.assertTrue (cur_line == target_line, "Stepped to line %d instead
of expected %d with pattern '%s'."%(cur_line, target_line, pattern))
AssertionError: False is not True : Stepped to line 0 instead of expected
19 with pattern 'intermediate_return_value =
called_from_nodebug_actual(some_value)'.
Config=i686-d:\src\llvmbuild\ninja_release\bin\clang.exe
Session info generated @ Thu Nov 12 15:44:43 2015
To rerun this test, issue the following command from the 'test' directory:

If it's not obvious what the problem is, can we revert this until we figure
it out and then reland it?

On Thu, Nov 12, 2015 at 2:34 PM Jim Ingham via lldb-commits <
lldb-commits at lists.llvm.org> wrote:

> Author: jingham
> Date: Thu Nov 12 16:32:09 2015
> New Revision: 252963
>
> URL: http://llvm.org/viewvc/llvm-project?rev=252963&view=rev
> Log:
> Another little stepping optimization: if any of the source step commands
> are running through a range
> of addresses, and the range has no branches, instead of running to the
> last instruction and
> single-stepping over that, run to the first instruction after the end of
> the range.  If there
> are no branches in the current range, then the bytes right after it have
> to be in the current
> function, and have to be instructions not data in code, so this is safe.
> And it cuts down one
> extra stepi per source range step.
>
> Incidentally, this also works around a bug in the llvm Intel assembler
> where it treats the "rep"
> prefix as a separate instruction from the repeated instruction.  If that
> were at the end of a
> line range, then we would put a trap in place of the repeated instruction,
> which is undefined
> behavior.  Current processors just ignore the repetition in this case,
> which changes program behavior.
> Since there would never be a line range break after the rep prefix, always
> doing the range stepping
> to the beginning of the new range avoids this problem.
>
> <rdar://problem/23461686>
>
> Modified:
>     lldb/trunk/source/Target/ThreadPlanStepRange.cpp
>
> Modified: lldb/trunk/source/Target/ThreadPlanStepRange.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/ThreadPlanStepRange.cpp?rev=252963&r1=252962&r2=252963&view=diff
>
> ==============================================================================
> --- lldb/trunk/source/Target/ThreadPlanStepRange.cpp (original)
> +++ lldb/trunk/source/Target/ThreadPlanStepRange.cpp Thu Nov 12 16:32:09
> 2015
> @@ -390,12 +390,19 @@ ThreadPlanStepRange::SetNextBranchBreakp
>          if (branch_index == UINT32_MAX)
>          {
>              branch_index = instructions->GetSize() - 1;
> +            InstructionSP last_inst =
> instructions->GetInstructionAtIndex(branch_index);
> +            size_t last_inst_size = last_inst->GetOpcode().GetByteSize();
> +            run_to_address = last_inst->GetAddress();
> +            run_to_address.Slide(last_inst_size);
> +        }
> +        else if (branch_index - pc_index > 1)
> +        {
> +            run_to_address =
> instructions->GetInstructionAtIndex(branch_index)->GetAddress();
>          }
>
> -        if (branch_index - pc_index > 1)
> +        if (run_to_address.IsValid())
>          {
>              const bool is_internal = true;
> -            run_to_address =
> instructions->GetInstructionAtIndex(branch_index)->GetAddress();
>              m_next_branch_bp_sp =
> GetTarget().CreateBreakpoint(run_to_address, is_internal, false);
>              if (m_next_branch_bp_sp)
>              {
>
>
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>
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