A number of debuginfo tests now fail on Windows/GNU and maybe other platforms

[petrochenkov]

If I remember correctly, this regression happened after upgrade to LLVM 7 - #51966.

Failing tests on MSYS2's gdb (GNU gdb (GDB) 7.12.1):

[debuginfo-gdb] debuginfo\borrowed-c-style-enum.rs
[debuginfo-gdb] debuginfo\c-style-enum-in-composite.rs
[debuginfo-gdb] debuginfo\generic-enum-with-different-disr-sizes.rs

Failing tests on mingw-w64's gdb from x86_64-7.2.0-posix-seh-rt_v5-rev1 toolchain (GNU gdb (GDB) 8.0.1):

[debuginfo-gdb] debuginfo\borrowed-c-style-enum.rs
[debuginfo-gdb] debuginfo\borrowed-enum.rs
[debuginfo-gdb] debuginfo\c-style-enum-in-composite.rs
[debuginfo-gdb] debuginfo\generic-enum-with-different-disr-sizes.rs
[debuginfo-gdb] debuginfo\generic-struct-style-enum.rs
[debuginfo-gdb] debuginfo\generic-tuple-style-enum.rs
[debuginfo-gdb] debuginfo\struct-style-enum.rs
[debuginfo-gdb] debuginfo\tuple-style-enum.rs
[debuginfo-gdb] debuginfo\unique-enum.rs

For the borrowed-c-style-enum test the failure reason is

error: line not found in debugger output: $1 = borrowed_c_style_enum::ABC::TheA

cc @tromey @michaelwoerister

[petrochenkov]

Full gdb outputs (with some fun windows/gnu-specific warnings that would be nice to fix in addition to the test error):

MSYS:

---- [debuginfo-gdb] debuginfo\borrowed-c-style-enum.rs stdout ----
NOTE: compiletest thinks it is using GDB with native rust support
NOTE: compiletest thinks it is using GDB version 7012001

error: line not found in debugger output: $1 = borrowed_c_style_enum::ABC::TheA
status: exit code: 0
command: PATH="C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\stage1\lib\rustlib\x86_64-pc-windows-gnu\lib;C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\llvm\build\bin;C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\stage0-bootstrap-tools\x86_64-pc-windows-gnu\release\deps;C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\stage0\bin;C:\msys64\mingw64\bin;C:\Users\we\.cargo\bin;C:\Program Files\CMake\bin;C:\Program Files\Git\cmd;C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin;C:\ProgramData\chocolatey\bin;C:\msys64\mingw64\bin;C:\msys64\usr\local\bin;C:\msys64\usr\bin;C:\msys64\usr\bin;C:\Windows\System32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\msys64\usr\bin\site_perl;C:\msys64\usr\bin\vendor_perl;C:\msys64\usr\bin\core_perl" "C:\\msys64\\usr\\bin\\gdb" "-quiet" "-batch" "-nx" "-command=C:\\msys64\\home\\we\\rust\\build\\x86_64-pc-windows-gnu\\test\\debuginfo\\borrowed-c-style-enum\\borrowed-c-style-enum.debugger.script"
stdout:
------------------------------------------
GNU gdb (GDB) 7.12.1
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-pc-msys".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word".
Breakpoint 1 at 0x401581: file C:\msys64\home\we\rust\src/test\debuginfo\borrowed-c-style-enum.rs, line 61.
[New Thread 6384.0x19f8]

Breakpoint 1, borrowed_c_style_enum::main::h533312d9b0c462da () at C:\msys64\home\we\rust\src/test\debuginfo\borrowed-c-style-enum.rs:61
61          zzz(); // #break
$1 = borrowed_c_style_enum::TheA
$2 = borrowed_c_style_enum::TheB
$3 = borrowed_c_style_enum::TheC
A debugging session is active.

        Inferior 1 [process 6384] will be killed.

Quit anyway? (y or n) [answered Y; input not from terminal]

------------------------------------------
stderr:
------------------------------------------
Warning: /home/we/rust/C: No such file or directory.
Warning: /home/we/rust/msys64homewerust./src/etc: No such file or directory.
warning: SHIMVIEW: ShimInfo(Complete)

------------------------------------------

mingw-w64:

---- [debuginfo-gdb] debuginfo\borrowed-c-style-enum.rs stdout ----
NOTE: compiletest thinks it is using GDB with native rust support
NOTE: compiletest thinks it is using GDB version 8000001

error: line not found in debugger output: $1 = borrowed_c_style_enum::ABC::TheA
status: exit code: 0
command: PATH="C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\stage1\lib\rustlib\x86_64-pc-windows-gnu\lib;C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\llvm\build\bin;C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\stage0-bootstrap-tools\x86_64-pc-windows-gnu\release\deps;C:\msys64\home\we\rust\build\x86_64-pc-windows-gnu\stage0\bin;C:\msys64\mingw64\bin;C:\Users\we\.cargo\bin;C:\Program Files\CMake\bin;C:\Program Files\Git\cmd;C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin;C:\ProgramData\chocolatey\bin;C:\msys64\mingw64\bin;C:\msys64\usr\local\bin;C:\msys64\usr\bin;C:\msys64\usr\bin;C:\Windows\System32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\msys64\usr\bin\site_perl;C:\msys64\usr\bin\vendor_perl;C:\msys64\usr\bin\core_perl" "C:\\mingw-w64\\x86_64-7.2.0-posix-seh-rt_v5-rev1\\mingw64\\bin\\gdb" "-quiet" "-batch" "-nx" "-command=C:\\msys64\\home\\we\\rust\\build\\x86_64-pc-windows-gnu\\test\\debuginfo\\borrowed-c-style-enum\\borrowed-c-style-enum.debugger.script"
stdout:
------------------------------------------
GNU gdb (GDB) 8.0.1
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-w64-mingw32".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word".
Breakpoint 1 at 0x401581: file C:\msys64\home\we\rust\src/test\debuginfo\borrowed-c-style-enum.rs, line 61.
[New Thread 5532.0x7c]

Breakpoint 1, borrowed_c_style_enum::main () at C:\msys64\home\we\rust\src/test\debuginfo\borrowed-c-style-enum.rs:61
61          zzz(); // #break
$1 = borrowed_c_style_enum::TheA
$2 = borrowed_c_style_enum::TheB
$3 = borrowed_c_style_enum::TheC
A debugging session is active.

        Inferior 1 [process 5532] will be killed.

Quit anyway? (y or n) [answered Y; input not from terminal]

------------------------------------------
stderr:
------------------------------------------
Warning: C:msys64homewerust./src/etc: No such file or directory.
warning: SHIMVIEW: ShimInfo(Complete)

------------------------------------------

[petrochenkov]

#52452 looks very similar.

[petrochenkov]

I no longer observe these failures on MSYS2's gdb (GNU gdb (GDB) 7.12.1).