Stepping into constructors broken

[dwilliamson]

Issue Type: Bug

Stepping into constructors seems to step elsewhere. See this example:

Actions taken:

• Press F5 to launch debugger and hit initial breakpoint.
• F10 to game::Host constructor.
• F11 to step into constructor.
• Subsequent F10 presses are not stepping on any code.

The only way to work around this is to put a breakpoint inside the constructor itself:

Actions taken:

• Press F5 to launch debugger and hit initial breakpoint.
• Press F5 again to jump to next breakpoint in the constructor.
• Subsequent F10 steps on correct code.

In cases where the constructor has initializers the separation is worse.

It appears to be stepping through some prologue code: if I continue to press F10 in the first example it will eventually end up back at the constructor entry-point, allowing me to continue debugging.

Extension version: 0.22.1
VS Code version: Code 1.33.0 (0dd516dd412d42323fc3464531b1c715d51c4c1a, 2019-04-04T15:14:28.026Z)
OS version: Windows_NT x64 10.0.17134

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-6800K CPU @ 3.40GHz (12 x 3398)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: disabled_software rasterization: enabled surface_synchronization: enabled_on video_decode: enabled webgl: enabled webgl2: enabled
Memory (System)	31.91GB (18.92GB free)
Process Argv
Screen Reader	no
VM	0%

[sean-mcmanus]

What is your debugger "type"? I'm not reproing this with the cppvsdbg. Are you able to step into library constructors such as std::lock_guard?

[dwilliamson]

It's cppvsdbg and I'm using Visual Studio 12.0.

Compiler command-line is:

cl.exe /c /showIncludes /errorReport:none /nologo /W3 /MTd /EHsc /arch:IA32 /fp:precise /Zp8 /Gd /Zi /GR- /Od /D WIN32 /D _WINDOWS /D _CRT_SECURE_NO_WARNINGS /D _SCL_SECURE_NO_WARNINGS /D _CRT_NONSTDC_NO_WARNINGS /FC /Fdvc100.pdb

Linker command-line is:

link.exe /ERRORREPORT:NONE /VERBOSE:LIB /SAFESEH /DEBUG /NOLOGO /MACHINE:x86 /OPT:NOREF /OPT:NOICF /SUBSYSTEM:WINDOWS /NODEFAULTLIB

If it makes a difference I'm using my own CRT but that shouldn't affect codegen.

[sean-mcmanus]

Does this repro with 0.21.0 or earlier? We updated our cppvsdbg in 0.22.0 in order to support the newer C++17 language features like structured bindings (see #3197 ), which may have regressed older compilers.

[dwilliamson]

I just tried these versions:

0.22.0
0.21.0
0.16.0

It repros on all of them. Interestingly, where it steps varies between builds; I've had one constructor step off beyond the end of a file.

I have never really paid attention to stepping into constructors before, but I do know that it works on x64/Linux.

I might be able to get a simple repro.

[sean-mcmanus]

It's possible it could be a bug with how the pdb info is generated with that compiler, i.e. you might try a newer compiler?

Our debugger team is pretty busy with other stuff, so I don't know if they'll have time to investigate a repro.

[dwilliamson]

I have the same issue with WinDbg and I'm sure this is new behaviour.