Make Debug Info work with --gc=G1.

In particular, when G1 is used together with `-H:-UseCompressedReferences`.
oracle · Jan 16, 2023 · 058563c · 058563c
1 parent fe66a0d
commit 058563c
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Showing 2 changed files with 9 additions and 6 deletions.
diff --git a/...tratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debugentry/DebugInfoBase.java b/...tratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debugentry/DebugInfoBase.java
@@ -227,8 +227,8 @@ public void installDebugInfo(DebugInfoProvider debugInfoProvider) {
          */
         int oopTagsMask = debugInfoProvider.oopTagsMask();
 
-        /* Tag bits must be between 1 and 32 for us to emit as DW_OP_lit<n>. */
-        assert oopTagsMask > 0 && oopTagsMask < 32;
+        /* Tag bits must be between 0 and 32 for us to emit as DW_OP_lit<n>. */
+        assert oopTagsMask >= 0 && oopTagsMask < 32;
         /* Mask must be contiguous from bit 0. */
         assert ((oopTagsMask + 1) & oopTagsMask) == 0;
 

diff --git a/...m/src/com.oracle.objectfile/src/com/oracle/objectfile/elf/dwarf/DwarfInfoSectionImpl.java b/...m/src/com.oracle.objectfile/src/com/oracle/objectfile/elf/dwarf/DwarfInfoSectionImpl.java
@@ -1687,7 +1687,7 @@ public int writeIndirectOopConversionExpression(boolean isHub, byte[] buffer, in
          *
          * The setting for option -H:+/-SpawnIsolates is determined by useHeapBase == true/false.
          *
-         * The setting for option -H:+/-UseCompressedReferences is determined by oopShiftCount ==
+         * The setting for option -H:+/-UseCompressedReferences is determined by oopTagsShift ==
          * zero/non-zero
          */
 
@@ -1760,10 +1760,13 @@ public int writeIndirectOopConversionExpression(boolean isHub, byte[] buffer, in
                     mask = dwarfSections.oopTagsMask();
                     exprSize += 3;
                 } else {
-                    /* We need two shifts to remove the bits. */
-                    rightShift = oopTagsShift;
+                    /* We need one or two shifts to remove the bits. */
+                    if (oopTagsShift != 0) { // -H:+UseCompressedReferences
+                        rightShift = oopTagsShift;
+                        exprSize += 2;
+                    }
                     leftShift = oopCompressShift;
-                    exprSize += 4;
+                    exprSize += 2;
                 }
             } else {
                 /* No flags to deal with, so we need either an uncompress or nothing. */