Test failure: ilasm round-trip ver_fg_13

[BruceForstall]

With:

set COMPlus_TieredCompilation=0
set RunningIlasmRoundTrip=1

>pushd c:\gh\runtime\artifacts\tests\coreclr\Windows_NT.x64.Release\JIT\jit64\verif\sniff\fg\ver_fg_13
>call c:\gh\runtime\artifacts\tests\coreclr\Windows_NT.x64.Release\JIT\jit64\verif\sniff\fg\ver_fg_13\ver_fg_13.cmd -coreroot c:\gh\runtime\artifacts\tests\coreclr\Windows_NT.x64.Debug\tests\Core_Root

BEGIN EXECUTION
c:\gh\runtime\artifacts\tests\coreclr\Windows_NT.x64.Debug\tests\Core_Root\ildasm.exe /raweh /out=ver_fg_13.dasm.il ver_fg_13.dll
c:\gh\runtime\artifacts\tests\coreclr\Windows_NT.x64.Debug\tests\Core_Root\ilasm.exe /output=ver_fg_13.asm.dll -QUIET -NOLOGO -DEBUG=OPT -OPTIMIZE ver_fg_13.dasm.il
ver_fg_13.dasm.il(94) : error : Unable to find forward reference label 'IL_000e' called from PC=36
ver_fg_13.dasm.il(94) : error : Method 'test2' compilation failed.
***** FAILURE *****
EXECUTION OF ILASM - FAILED 1

[markples]

Test seems to intentionally have invalid IR

...
		leave -22
...

in a method called from Main, which catches InvalidProgramException.

The -22 seems to be an explicit relative IL offset (from the next instruction) rather than the usual use of a label in manually written IL files. However, -22 doesn't line up with an instruction.

This ilasms fine in the test tree, but ildasm attempts to write a label IL_000e as the destination rather than -22. My guess is that the emitter needs to check if the target exists before writing a label. Since ildasm creates a label for every instruction, presumably the assumption was that targets would always be there.

Note that this is hard to see in the original il file because the instructions aren't labeled, but you can see the -22 in the original file and then the IL_000e in the disasm version.