[NativeAOT] ObjectWriter for MacOS should be built and published from the Main branch

[VSadov]

While working on adding TLS support it was discovered that we may be omitting building/publishing ObjectWriter for MacOS.
The libobjwriter.dylib in the nuget that is used by the runtime build is old - from February 6.
That is before merging ObjectWriter into dotnet/llvm-project/main

Also there could be that we accumulated a few issues/bugs in the main branch as a part of the merge or since then.
The binary that is built from main causes dsymutil to OOM which breaks the smoketests build. There are also warnings like:

EXEC : warning : DWARF unit from offset 0x00000000 incl. to offset 0x00133e38 excl. tries to read DIEs at offset 0x00133e38 [/Users/vs/aot01/runtime/src/tests/nativeaot/SmokeTests/UnitTests/UnitTests.csproj] [/Users/vs/aot01/runtime/src/tests/build.proj]
EXEC : warning : DWARF unit from offset 0x00000000 incl. to offset 0x001ce1c2 excl. tries to read DIEs at offset 0x001ce1c2 [/Users/vs/aot01/runtime/src/tests/nativeaot/SmokeTests/Reflection/Reflection_FromUsage.csproj] [/Users/vs/aot01/runtime/src/tests/build.proj]
EXEC : warning : DWARF unit from offset 0x00000000 incl. to offset 0x00129592 excl. tries to read DIEs at offset 0x00129592 [/Users/vs/aot01/runtime/src/tests/nativeaot/SmokeTests/Reflection/Reflection.csproj] [/Users/vs/aot01/runtime/src/tests/build.proj]

This might be happening only on some scenarios and hopefully due to some simple issue, but it prevents using Main branch for further development/testing on MacOS.

Re: dotnet/llvm-project#425

[ghost]

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

Issue Details

---

While working on adding TLS support it was discovered that we may be omitting building/publishing ObjectWriter for MacOS.
The libobjwriter.dylib in the nuget that is used by the runtime build is old - from February 6.
That is before merging ObjectWriter into dotnet/llvm-project/main

Also there could be that we accumulated a few issues/bugs in the main branch as a part of the merge or since then.
The binary that is built from main causes dsymutil to OOM which breaks the smoketests build. There are also warnings like:

EXEC : warning : DWARF unit from offset 0x00000000 incl. to offset 0x00133e38 excl. tries to read DIEs at offset 0x00133e38 [/Users/vs/aot01/runtime/src/tests/nativeaot/SmokeTests/UnitTests/UnitTests.csproj] [/Users/vs/aot01/runtime/src/tests/build.proj]
EXEC : warning : DWARF unit from offset 0x00000000 incl. to offset 0x001ce1c2 excl. tries to read DIEs at offset 0x001ce1c2 [/Users/vs/aot01/runtime/src/tests/nativeaot/SmokeTests/Reflection/Reflection_FromUsage.csproj] [/Users/vs/aot01/runtime/src/tests/build.proj]
EXEC : warning : DWARF unit from offset 0x00000000 incl. to offset 0x00129592 excl. tries to read DIEs at offset 0x00129592 [/Users/vs/aot01/runtime/src/tests/nativeaot/SmokeTests/Reflection/Reflection.csproj] [/Users/vs/aot01/runtime/src/tests/build.proj]

This might be happening only on some scenarios and hopefully due to some simple issue, but it prevents using Main branch for further development/testing on MacOS.

Re: dotnet/llvm-project#425

Author:	VSadov
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	-

[filipnavara]

I plan to look into it.

[filipnavara]

I can reproduce it. The DWARF info in the .o file has unbalanced nesting and ends with missing NULL terminator.

[filipnavara]

The unbalanced nesting happens here:

-0x00001e06:   DW_TAG_enumeration_type
-                DW_AT_name	("Reflection_ReflectionTest_TestAttributeExpressions_MyEnum")
-                DW_AT_type	(0x000000c0 "int")
-                DW_AT_byte_size	(0x04)
-
-0x00001e10:     NULL
+0x00001e01:   DW_TAG_enumeration_type
+                DW_AT_name	("Reflection_ReflectionTest_TestAttributeExpressions_MyEnum")
+                DW_AT_type	(0x000000bb "int")
+                DW_AT_byte_size	(0x04)

[filipnavara]

I submitted the ObjWriter fix. Someone else will have to fix up DARC once that is merged.

[VSadov]

I just want to confirm the ObjWriter fix. I am able to build it on MacOS and then build/run tests with that ObjWriter.

[directhex]

@filipnavara you're a hero. This has been a problem for me.

[filipnavara]

Happy to help! Are you going to take care of the DARC changes as part of the LLVM 16 retargeting? Should I open PR against the LLVM 16 branch as well?

[directhex]

Yeah, I already made the DARC changes in my LLVM 16 branch, hence running into this

[akoeplinger]

We might want to make the DARC changes separately so we don't depend on the LLVM 16 work in case that one gets delayed.

[agocke]

This should be done.