Store entry assembly path for easy access for diagnostics

[elinor-fung]

• Add g_EntryAssemblyPath global variable holding the full path to the entry assembly
  • Set right before loading the entry assembly (so also before startup hooks are run) - NULL if there is no entry assembly
• Ensure value is included dumps
  • For triage dumps, the dumped value is updated to only be the assembly file name instead of the full path

Example:

0:000> ||
.  0 User mini triage dump: C:\repos\helloworld\triage.dmp
0:000> x coreclr!g_EntryAssemblyPath
00007ffb`14f7dd58 coreclr!g_EntryAssemblyPath = 0x00000211`88016eb0 "helloworld.dll"

0:000> ||
.  0 User mini dump: C:\repos\helloworld\mini.dmp
0:000> x coreclr!g_EntryAssemblyPath
00007ffb`14f7dd58 coreclr!g_EntryAssemblyPath = 0x00000211`88016eb0 "C:\repos\helloworld\bin\Debug\net8.0\helloworld.dll"

Fixes #94474

@leculver
@dotnet/dotnet-diag

[ghost]

Tagging subscribers to this area: @vitek-karas, @agocke, @VSadov
See info in area-owners.md if you want to be subscribed.

Issue Details

---

• Add g_EntryAssemblyPath global variable holding the full path to the entry assembly
  • Set right before loading the entry assembly (so also before startup hooks are run) - NULL if there is no entry assembly
• Ensure value is included dumps
  • For triage dumps, the dumped value is updated to only be the assembly file name instead of the full path

Example:

0:000> ||
.  0 User mini triage dump: C:\repos\helloworld\triage.dmp
0:000> x coreclr!g_EntryAssemblyPath
00007ffb`14f7dd58 coreclr!g_EntryAssemblyPath = 0x00000211`88016eb0 "helloworld.dll"

0:000> ||
.  0 User mini dump: C:\repos\helloworld\mini.dmp
0:000> x coreclr!g_EntryAssemblyPath
00007ffb`14f7dd58 coreclr!g_EntryAssemblyPath = 0x00000211`88016eb0 "C:\repos\helloworld\bin\Debug\net8.0\helloworld.dll"

Fixes #94474

@leculver
@dotnet/dotnet-diag

Author:	elinor-fung
Assignees:	-
Labels:	area-AssemblyLoader-coreclr
Milestone:	-

[elinor-fung]

/backport to release/8.0-staging

[elinor-fung]

/backport to release/7.0-staging

[github-actions]

Started backporting to release/8.0-staging: https://github.com/dotnet/runtime/actions/runs/6937553925

[github-actions]

Started backporting to release/7.0-staging: https://github.com/dotnet/runtime/actions/runs/6937554937

[github-actions]

@elinor-fung backporting to release/8.0-staging failed, the patch most likely resulted in conflicts:

$ git am --3way --ignore-whitespace --keep-non-patch changes.patch

Applying: Store entry assembly path for easy access for diagnostics (dumps)
Using index info to reconstruct a base tree...
M	src/coreclr/inc/dacvars.h
M	src/coreclr/vm/vars.cpp
M	src/coreclr/vm/vars.hpp
Falling back to patching base and 3-way merge...
Auto-merging src/coreclr/vm/vars.hpp
CONFLICT (content): Merge conflict in src/coreclr/vm/vars.hpp
Auto-merging src/coreclr/vm/vars.cpp
CONFLICT (content): Merge conflict in src/coreclr/vm/vars.cpp
Auto-merging src/coreclr/inc/dacvars.h
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Store entry assembly path for easy access for diagnostics (dumps)
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!

[github-actions]

@elinor-fung an error occurred while backporting to release/8.0-staging, please check the run log for details!

Error: git am failed, most likely due to a merge conflict.

[github-actions]

@elinor-fung backporting to release/7.0-staging failed, the patch most likely resulted in conflicts:

$ git am --3way --ignore-whitespace --keep-non-patch changes.patch

Applying: Store entry assembly path for easy access for diagnostics (dumps)
Using index info to reconstruct a base tree...
M	src/coreclr/debug/daccess/enummem.cpp
M	src/coreclr/inc/daccess.h
M	src/coreclr/inc/dacvars.h
M	src/coreclr/vm/corhost.cpp
M	src/coreclr/vm/vars.cpp
M	src/coreclr/vm/vars.hpp
Falling back to patching base and 3-way merge...
Auto-merging src/coreclr/vm/vars.hpp
CONFLICT (content): Merge conflict in src/coreclr/vm/vars.hpp
Auto-merging src/coreclr/vm/vars.cpp
CONFLICT (content): Merge conflict in src/coreclr/vm/vars.cpp
Auto-merging src/coreclr/vm/corhost.cpp
Auto-merging src/coreclr/inc/dacvars.h
Auto-merging src/coreclr/inc/daccess.h
Auto-merging src/coreclr/debug/daccess/enummem.cpp
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Store entry assembly path for easy access for diagnostics (dumps)
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!

[github-actions]

@elinor-fung an error occurred while backporting to release/7.0-staging, please check the run log for details!

Error: git am failed, most likely due to a merge conflict.

[mikem8361]

How is this supposed to be used? It looks like a DAC'ized global variable was added (g_EntryAssemblyPath) but that is only accessible by the DAC and there is no DAC API exposed to query it.

[elinor-fung]

It is simply accessed as a global variable rather than via a DAC API.

[mikem8361]

The problem is that to access the global the tooling needs the symbol file. It is was an export, then tools like createdump or dotnet-dump, etc. could use it. I know that !analyze/Watson was it's intended usage so requiring a native debugger and symbols.