Use relative path in DW_AT_comp_dir if possible

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debuginfo/DebugInfoProvider.java

@@ -82,8 +82,10 @@ interface DebugFileInfo {
         Path filePath();
 
         /**
-         * @return a relative path to the source cache containing the cached source file of a file
-         *         element or {@code null} if sources are not available.
+         * @return the path to the source cache containing the cached source file of a file element
+         *         or {@code null} if sources are not available. Relative paths to the target
+         *         directory are preferred over absolute paths, to make it easier to move the binary
+         *         and the cache directory around.
          */
         Path cachePath();
     }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/SubstrateOptions.java

@@ -476,14 +476,28 @@ public static void defaultDebugInfoValueUpdateHandler(EconomicMap<OptionKey<?>,
     @Option(help = "Directory under which to create source file cache for Application or GraalVM classes")//
     public static final HostedOptionKey<String> DebugInfoSourceCacheRoot = new HostedOptionKey<>("sources");
 
-    public static Path getDebugInfoSourceCacheRoot() {
+    /**
+     * Returns {@link SubstrateOptions#DebugInfoSourceCacheRoot} as an absolute path, by resolving
+     * it on {@link SubstrateOptions#Path} if it's not already an absolute path.
+     *
+     * @return the source cache root as an absolute path
+     */
+    public static Path getDebugInfoSourceCacheRootAsAbsolutePath() {
         try {
             return Paths.get(Path.getValue()).resolve(DebugInfoSourceCacheRoot.getValue());
         } catch (InvalidPathException ipe) {
             throw UserError.abort("Invalid path provided for option DebugInfoSourceCacheRoot %s", DebugInfoSourceCacheRoot.getValue());
         }
     }
 
+    public static Path getDebugInfoSourceCacheRoot() {
+        try {
+            return Paths.get(DebugInfoSourceCacheRoot.getValue());
+        } catch (InvalidPathException ipe) {
+            throw UserError.abort("Invalid path provided for option DebugInfoSourceCacheRoot %s", DebugInfoSourceCacheRoot.getValue());
+        }
+    }
+
     @Option(help = "Omit generation of DebugLineInfo originating from inlined methods") //
     public static final HostedOptionKey<Boolean> OmitInlinedMethodDebugLineInfo = new HostedOptionKey<>(true);
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageDebugInfoProvider.java

@@ -87,6 +87,7 @@
 class NativeImageDebugInfoProvider implements DebugInfoProvider {
     private final DebugContext debugContext;
     private final NativeImageCodeCache codeCache;
+    private final Path cachePath;
     @SuppressWarnings("unused") private final NativeImageHeap heap;
     boolean useHeapBase;
     int compressShift;
@@ -101,6 +102,7 @@ class NativeImageDebugInfoProvider implements DebugInfoProvider {
         super();
         this.debugContext = debugContext;
         this.codeCache = codeCache;
+        this.cachePath = SubstrateOptions.getDebugInfoSourceCacheRoot();
         this.heap = heap;
         ObjectHeader objectHeader = Heap.getHeap().getObjectHeader();
         ObjectInfo primitiveFields = heap.getObjectInfo(StaticFieldsSupport.getStaticPrimitiveFields());
@@ -236,8 +238,6 @@ private static String toJavaName(JavaType javaType) {
         return javaType.toJavaName();
     }
 
-    private final Path cachePath = SubstrateOptions.getDebugInfoSourceCacheRoot();
-
     private abstract class NativeImageDebugFileInfo implements DebugFileInfo {
         private Path fullFilePath;
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageViaCC.java

@@ -461,7 +461,7 @@ public LinkerInvocation write(DebugContext debug, Path outputDirectory, Path tem
                 }
 
                 if (SubstrateOptions.GenerateDebugInfo.getValue() > 0) {
-                    BuildArtifacts.singleton().add(ArtifactType.DEBUG_INFO, SubstrateOptions.getDebugInfoSourceCacheRoot());
+                    BuildArtifacts.singleton().add(ArtifactType.DEBUG_INFO, SubstrateOptions.getDebugInfoSourceCacheRootAsAbsolutePath());
                     if (OS.getCurrent() == OS.WINDOWS) {
                         BuildArtifacts.singleton().add(ArtifactType.DEBUG_INFO, imagePath.resolveSibling(imageName + ".pdb"));
                     } else {

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/sources/SourceCache.java

@@ -94,7 +94,7 @@ public class SourceCache {
      * Create the source cache.
      */
     protected SourceCache() {
-        basePath = SubstrateOptions.getDebugInfoSourceCacheRoot();
+        basePath = SubstrateOptions.getDebugInfoSourceCacheRootAsAbsolutePath();
         srcRoots = new ArrayList<>();
         specialSrcRoots = new HashMap<>();
         addJDKSources();