[Backport][22.3] c++ compatible mangling support

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debugentry/ArrayTypeEntry.java

@@ -61,4 +61,15 @@ public void addDebugInfo(DebugInfoBase debugInfoBase, DebugTypeInfo debugTypeInf
     public TypeEntry getElementType() {
         return elementType;
     }
+
+    public String getLoaderId() {
+        TypeEntry type = elementType;
+        while (type.isArray()) {
+            type = ((ArrayTypeEntry) type).elementType;
+        }
+        if (type.isClass()) {
+            return ((ClassEntry) type).getLoaderId();
+        }
+        return "";
+    }
 }

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debugentry/ClassEntry.java

@@ -62,6 +62,10 @@ public class ClassEntry extends StructureTypeEntry {
      * Details of the associated file.
      */
     private FileEntry fileEntry;
+    /**
+     * Details of the associated loader.
+     */
+    private LoaderEntry loader;
     /**
      * Details of methods located in this instance.
      */
@@ -108,6 +112,7 @@ public ClassEntry(String className, FileEntry fileEntry, int size) {
         super(className, size);
         this.interfaces = new ArrayList<>();
         this.fileEntry = fileEntry;
+        this.loader = null;
         this.methods = new ArrayList<>();
         this.methodsIndex = new HashMap<>();
         this.normalCompiledEntries = new ArrayList<>();
@@ -150,6 +155,10 @@ public void addDebugInfo(DebugInfoBase debugInfoBase, DebugTypeInfo debugTypeInf
         if (superType != null) {
             this.superClass = debugInfoBase.lookupClassEntry(superType);
         }
+        String loaderName = debugInstanceTypeInfo.loaderName();
+        if (!loaderName.isEmpty()) {
+            this.loader = debugInfoBase.ensureLoaderEntry(loaderName);
+        }
         debugInstanceTypeInfo.interfaces().forEach(interfaceType -> processInterface(interfaceType, debugInfoBase, debugContext));
         /* Add details of fields and field types */
         debugInstanceTypeInfo.fieldInfoProvider().forEach(debugFieldInfo -> this.processField(debugFieldInfo, debugInfoBase, debugContext));
@@ -256,6 +265,10 @@ public FileEntry getFileEntry() {
         return fileEntry;
     }
 
+    public String getLoaderId() {
+        return (loader != null ? loader.getLoaderId() : "");
+    }
+
     /**
      * Retrieve a stream of all compiled method entries for this class, including both normal and
      * deopt fallback compiled methods.

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debugentry/DebugInfoBase.java

@@ -141,6 +141,17 @@ public abstract class DebugInfoBase {
      * Index of files which contain primary or secondary ranges keyed by path.
      */
     private Map<Path, FileEntry> filesIndex = new HashMap<>();
+
+    /**
+     * List of all loaders associated with classes included in the image.
+     */
+    private List<LoaderEntry> loaders = new ArrayList<>();
+
+    /**
+     * Index of all loaders associated with classes included in the image.
+     */
+    private Map<String, LoaderEntry> loaderIndex = new HashMap<>();
+
     /**
      * Flag set to true if heap references are stored as addresses relative to a heap base register
      * otherwise false.
@@ -501,6 +512,15 @@ private DirEntry ensureDirEntry(Path filePath) {
         return dirEntry;
     }
 
+    protected LoaderEntry ensureLoaderEntry(String loaderId) {
+        LoaderEntry loaderEntry = loaderIndex.get(loaderId);
+        if (loaderEntry == null) {
+            loaderEntry = new LoaderEntry(uniqueDebugString(loaderId));
+            loaderIndex.put(loaderEntry.getLoaderId(), loaderEntry);
+        }
+        return loaderEntry;
+    }
+
     /* Accessors to query the debug info model. */
     public ByteOrder getByteOrder() {
         return byteOrder;
@@ -524,6 +544,15 @@ public FileEntry findFile(Path fullFileName) {
         return filesIndex.get(fullFileName);
     }
 
+    public List<LoaderEntry> getLoaders() {
+        return loaders;
+    }
+
+    @SuppressWarnings("unused")
+    public LoaderEntry findLoader(String id) {
+        return loaderIndex.get(id);
+    }
+
     public StringTable getStringTable() {
         return stringTable;
     }

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debugentry/LoaderEntry.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2020, Red Hat Inc. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.objectfile.debugentry;
+
+/**
+ * A LoaderEntry is used to record a unique id string for the class loader asscoiated with classes
+ * that can be susceptible to repeat definitions. In such cases the loader id can be used when
+ * constructing a unique linker symbol for methods and static fields of the class. That same id may
+ * need to be embedded in debug info that identifies class and method names.
+ */
+public class LoaderEntry {
+    String loaderId;
+
+    public LoaderEntry(String id) {
+        loaderId = id;
+    }
+
+    public String getLoaderId() {
+        return loaderId;
+    }
+}

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

@@ -138,6 +138,8 @@ public String toString() {
     public interface DebugInstanceTypeInfo extends DebugTypeInfo {
         int headerSize();
 
+        String loaderName();
+
         Stream<DebugFieldInfo> fieldInfoProvider();
 
         Stream<DebugMethodInfo> methodInfoProvider();

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/elf/dwarf/DwarfAbbrevSectionImpl.java

@@ -154,6 +154,15 @@ public void createContent() {
          * instance fields. They are not needed when typing local vars and parameters held in
          * registers or on the stack as they appear as raw addresses.
          *
+         * <li><code>code = namespace, tag = namespace, parent = class_unit, array_unit,
+         * interface_unit<code> - a wrap-around DIE that is used to embed all the normal level 1
+         * DIEs of a <code>class_unit</code> or <code>array_unit</code_unit> in a namespace. This is
+         * needed when the corresponding class/interface or array base element type have been loaded
+         * by a loader with a non-empty loader in order to ensure that mangled names for the class
+         * and its members can legitimately employ the loader id as a namespace prefix. Note that
+         * use of a namespace wrapper DIE causes all the embedded level 1+ DIEs documented above and
+         * all their children to be generated at a level one greater than documented here.
+         *
          * </ul>
          *
          * <ul>
@@ -198,7 +207,18 @@ public void createContent() {
          *
          * Details of each specific DIE contents are as follows:
          *
-         * Primitive Types: For each non-void Java primitive type there is a level 0 DIE defining a
+         * A single instance of the level 0 <code>builtin_unit</code> compile unit provides details
+         * of all Java primitive types and of the struct type which describes the layout of object
+         * headers, including array headers.
+         *
+         * <li><code>abbrev_code == builtin_unit, tag == DW_TAG_compilation_unit,
+         * has_children</code>
+         *
+         * <li><code>DW_AT_language : ... DW_FORM_data1</code>
+         *
+         * </ul>
+         *
+         * Primitive Types: For each non-void Java primitive type there is a level 1 DIE defining a
          * base type
          *
          * <ul>
@@ -225,7 +245,7 @@ public void createContent() {
          *
          * </ul>
          *
-         * Header: There is a level 0 DIE defining structure types used to define the various types
+         * Header: There is a level 1 DIE defining structure types used to define the various types
          * of header structure embedded at the start of every instance or array. All instances embed
          * the same object header. Array headers embed the object header as a parent type, allowing
          * an array to be viewed as a type of object. Multiple array headers structures are defined
@@ -243,7 +263,7 @@ public void createContent() {
          *
          * </ul>
          *
-         * Header Data: A level 1 DIE of type member is used to describe the fields of both object
+         * Header Data: A level 2 DIE of type member is used to describe the fields of both object
          * and array headers. This includes the type tag and other tag bits in all objects, the
          * length field in all arrays and any padding bytes needed to complete the layout.
          *
@@ -290,6 +310,20 @@ public void createContent() {
          *
          * </ul>
          *
+         * Namespace embedding:
+         *
+         * When the class loader associated with a class defined in a <code>class_unit</code>
+         * compile unit has a non-empty loader id string then a namespace DIE is used to wrap all
+         * its child DIEs. Otherwise the children are embedded directly. The namespace DIE has a
+         * single attribute defining the namespace's name as the loader id string.
+         *
+         * <li><code>abbrev_code == namespace, tag == DW_TAG_namespace, has_children</code>
+         *
+         * <li><code>DW_AT_name : ....... DW_FORM_strp</code>
+         *
+         * </ul>
+         *
+         *
          * Instance Class Structure: Each class_unit DIE contains a series of level 1 DIEs. The
          * first one describes the class layout. The normal layout does not include a data_location
          * attribute. However, an alternative layout, including that extra attribute, is provided to
@@ -663,10 +697,15 @@ public void createContent() {
          *
          * Array Structure: Each array_unit DIE contains four level 1 DIEs. The first one describes
          * the array layout. It has only one child, a super_reference DIE (see above) that
-         * references the appropriate array header type for an obnject aray or primitive array of
+         * references the appropriate array header type for an object array or primitive array of
          * the relevant primitive type). The size of the array layout is the same as the size of the
          * array header.
          *
+         * Note that when the base element type of the array is a class whose loader has an
+         * associated loader id the array's children are embedded in a namespace DIE. This is needed
+         * because the encoded type name for the array will include a namespace prefix in order to
+         * guarantee that it remains unique.
+         *
          * <ul>
          *
          * <li><code>abbrev_code == array_layout, tag == DW_TAG_class_type, has_children</code>
@@ -825,6 +864,8 @@ public int writeAbbrevs(DebugContext context, byte[] buffer, int p) {
         pos = writeVoidTypeAbbrev(context, buffer, pos);
         pos = writeObjectHeaderAbbrev(context, buffer, pos);
 
+        pos = writeNamespaceAbbrev(context, buffer, pos);
+
         pos = writeClassLayoutAbbrevs(context, buffer, pos);
         pos = writeClassReferenceAbbrev(context, buffer, pos);
         pos = writeMethodDeclarationAbbrevs(context, buffer, pos);
@@ -1002,6 +1043,21 @@ private int writeObjectHeaderAbbrev(@SuppressWarnings("unused") DebugContext con
         return pos;
     }
 
+    private int writeNamespaceAbbrev(@SuppressWarnings("unused") DebugContext context, byte[] buffer, int p) {
+        int pos = p;
+        pos = writeAbbrevCode(DwarfDebugInfo.DW_ABBREV_CODE_namespace, buffer, pos);
+        pos = writeTag(DwarfDebugInfo.DW_TAG_namespace, buffer, pos);
+        pos = writeFlag(DwarfDebugInfo.DW_CHILDREN_yes, buffer, pos);
+        pos = writeAttrType(DwarfDebugInfo.DW_AT_name, buffer, pos);
+        pos = writeAttrForm(DwarfDebugInfo.DW_FORM_strp, buffer, pos);
+        /*
+         * Now terminate.
+         */
+        pos = writeAttrType(DwarfDebugInfo.DW_AT_null, buffer, pos);
+        pos = writeAttrForm(DwarfDebugInfo.DW_FORM_null, buffer, pos);
+        return pos;
+    }
+
     private int writeClassLayoutAbbrevs(@SuppressWarnings("unused") DebugContext context, byte[] buffer, int p) {
         int pos = p;
         pos = writeClassLayoutAbbrev(context, DwarfDebugInfo.DW_ABBREV_CODE_class_layout1, buffer, pos);

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/elf/dwarf/DwarfDebugInfo.java

@@ -78,43 +78,44 @@ public class DwarfDebugInfo extends DebugInfoBase {
     public static final int DW_ABBREV_CODE_primitive_type = 5;
     public static final int DW_ABBREV_CODE_void_type = 6;
     public static final int DW_ABBREV_CODE_object_header = 7;
-    public static final int DW_ABBREV_CODE_class_layout1 = 8;
-    public static final int DW_ABBREV_CODE_class_layout2 = 9;
-    public static final int DW_ABBREV_CODE_class_pointer = 10;
-    public static final int DW_ABBREV_CODE_method_location = 11;
-    public static final int DW_ABBREV_CODE_abstract_inline_method = 12;
-    public static final int DW_ABBREV_CODE_static_field_location = 13;
-    public static final int DW_ABBREV_CODE_array_layout = 14;
-    public static final int DW_ABBREV_CODE_array_pointer = 15;
-    public static final int DW_ABBREV_CODE_interface_layout = 16;
-    public static final int DW_ABBREV_CODE_interface_pointer = 17;
-    public static final int DW_ABBREV_CODE_indirect_layout = 18;
-    public static final int DW_ABBREV_CODE_indirect_pointer = 19;
+    public static final int DW_ABBREV_CODE_namespace = 8;
+    public static final int DW_ABBREV_CODE_class_layout1 = 9;
+    public static final int DW_ABBREV_CODE_class_layout2 = 10;
+    public static final int DW_ABBREV_CODE_class_pointer = 11;
+    public static final int DW_ABBREV_CODE_method_location = 12;
+    public static final int DW_ABBREV_CODE_abstract_inline_method = 13;
+    public static final int DW_ABBREV_CODE_static_field_location = 14;
+    public static final int DW_ABBREV_CODE_array_layout = 15;
+    public static final int DW_ABBREV_CODE_array_pointer = 16;
+    public static final int DW_ABBREV_CODE_interface_layout = 17;
+    public static final int DW_ABBREV_CODE_interface_pointer = 18;
+    public static final int DW_ABBREV_CODE_indirect_layout = 19;
+    public static final int DW_ABBREV_CODE_indirect_pointer = 20;
     /* Level 2 DIEs. */
-    public static final int DW_ABBREV_CODE_method_declaration = 20;
-    public static final int DW_ABBREV_CODE_method_declaration_static = 21;
-    public static final int DW_ABBREV_CODE_field_declaration1 = 22;
-    public static final int DW_ABBREV_CODE_field_declaration2 = 23;
-    public static final int DW_ABBREV_CODE_field_declaration3 = 24;
-    public static final int DW_ABBREV_CODE_field_declaration4 = 25;
-    public static final int DW_ABBREV_CODE_header_field = 26;
-    public static final int DW_ABBREV_CODE_array_data_type = 27;
-    public static final int DW_ABBREV_CODE_super_reference = 28;
-    public static final int DW_ABBREV_CODE_interface_implementor = 29;
+    public static final int DW_ABBREV_CODE_method_declaration = 21;
+    public static final int DW_ABBREV_CODE_method_declaration_static = 22;
+    public static final int DW_ABBREV_CODE_field_declaration1 = 23;
+    public static final int DW_ABBREV_CODE_field_declaration2 = 24;
+    public static final int DW_ABBREV_CODE_field_declaration3 = 25;
+    public static final int DW_ABBREV_CODE_field_declaration4 = 26;
+    public static final int DW_ABBREV_CODE_header_field = 27;
+    public static final int DW_ABBREV_CODE_array_data_type = 28;
+    public static final int DW_ABBREV_CODE_super_reference = 29;
+    public static final int DW_ABBREV_CODE_interface_implementor = 30;
     /* Level 2+K DIEs (where inline depth K >= 0) */
-    public static final int DW_ABBREV_CODE_inlined_subroutine = 30;
-    public static final int DW_ABBREV_CODE_inlined_subroutine_with_children = 31;
+    public static final int DW_ABBREV_CODE_inlined_subroutine = 31;
+    public static final int DW_ABBREV_CODE_inlined_subroutine_with_children = 32;
     /* Level 2 DIEs. */
-    public static final int DW_ABBREV_CODE_method_parameter_declaration1 = 32;
-    public static final int DW_ABBREV_CODE_method_parameter_declaration2 = 33;
-    public static final int DW_ABBREV_CODE_method_parameter_declaration3 = 34;
-    public static final int DW_ABBREV_CODE_method_local_declaration1 = 35;
-    public static final int DW_ABBREV_CODE_method_local_declaration2 = 36;
+    public static final int DW_ABBREV_CODE_method_parameter_declaration1 = 33;
+    public static final int DW_ABBREV_CODE_method_parameter_declaration2 = 34;
+    public static final int DW_ABBREV_CODE_method_parameter_declaration3 = 35;
+    public static final int DW_ABBREV_CODE_method_local_declaration1 = 36;
+    public static final int DW_ABBREV_CODE_method_local_declaration2 = 37;
     /* Level 3 DIEs. */
-    public static final int DW_ABBREV_CODE_method_parameter_location1 = 37;
-    public static final int DW_ABBREV_CODE_method_parameter_location2 = 38;
-    public static final int DW_ABBREV_CODE_method_local_location1 = 39;
-    public static final int DW_ABBREV_CODE_method_local_location2 = 40;
+    public static final int DW_ABBREV_CODE_method_parameter_location1 = 38;
+    public static final int DW_ABBREV_CODE_method_parameter_location2 = 39;
+    public static final int DW_ABBREV_CODE_method_local_location1 = 40;
+    public static final int DW_ABBREV_CODE_method_local_location2 = 41;
 
     /*
      * Define all the Dwarf tags we need for our DIEs.
@@ -131,6 +132,7 @@ public class DwarfDebugInfo extends DebugInfoBase {
     public static final int DW_TAG_base_type = 0x24;
     public static final int DW_TAG_subprogram = 0x2e;
     public static final int DW_TAG_variable = 0x34;
+    public static final int DW_TAG_namespace = 0x39;
     public static final int DW_TAG_unspecified_type = 0x3b;
     public static final int DW_TAG_inlined_subroutine = 0x1d;
 
@@ -208,6 +210,11 @@ public class DwarfDebugInfo extends DebugInfoBase {
      * Value for DW_AT_language attribute with form DATA1.
      */
     public static final byte DW_LANG_Java = 0xb;
+    /**
+     * This field defines the value used for the DW_AT_language attribute of compile units.
+     *
+     */
+    public static final byte LANG_ENCODING = DW_LANG_Java;
     /*
      * Values for {@link DW_AT_inline} attribute with form DATA1.
      */