gdb debugging of native images without setting the sources directory no longer works as of GraalVM/Mandrel 21.1

[zakkak]

Describe the bug

oracle/graal@dee66ca (included in GraalVM/Mandrel >=21.1) started enforcing the use of absolute paths in DW_AT_comp_dir. These paths are essentially pointing to the location of the "sources" directory holding the source code corresponding to the binary being debugged. In Quarkus we copy the "sources" directory after the compilation is done:

quarkus/core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/NativeImageBuildStep.java

Lines 226 to 230 in 5b91e61

	final String sources = "sources";
	final Path generatedSources = outputDir.resolve(sources);
	final Path finalSources = outputTargetBuildItem.getOutputDirectory().resolve(sources);
	IoUtils.copy(generatedSources, finalSources);
	IoUtils.recursiveDelete(generatedSources);

As a result the absolute paths written in the DW_AT_comp_dir entries become invalid and thus the user needs to invoke directory path/to/sources in gdb to let it know where to find the sources. This was optional prior to 21.1 as long as gdb was started from the same directory containing the sources directory. This last part made debugging on deployment environments a bit easier as well, since the user could copy the sources directory next to the binary and start gdb from there without any additional configuration.

Expected behavior

When running gdb in the target directory, it should be able to detect the sources without additional configuration.

Actual behavior

gdb requires using directory to point it to the sources directory.

How to Reproduce?

1. Compile an application with -Dnative and -Dquarkus.native.debug.enabled=true
2. Enter target directory and run gdb <my-app-runner>
3. Run info func <part of a method name in the app> to get a method
4. Try to list that method, e.g. list myMethod

Output of uname -a or ver

No response

Output of java -version

No response

GraalVM version (if different from Java)

No response

Quarkus version or git rev

No response

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

No response

[quarkus-bot]

/cc @galderz