From 54d5e1445c952909f7dd1b042afddc3429c3dc99 Mon Sep 17 00:00:00 2001
From: John Dallaway <john@dallaway.org.uk>
Date: Sun, 2 Jul 2023 14:49:00 +0100
Subject: [PATCH] Support DWARF attribute form DW_FORM_implicit_const

---
 .../.settings/.api_filters                    |  6 +++++
 .../org.eclipse.cdt.core/META-INF/MANIFEST.MF |  2 +-
 .../eclipse/cdt/utils/debug/dwarf/Dwarf.java  | 26 +++++++++++++++----
 .../cdt/utils/debug/dwarf/DwarfConstants.java |  5 ++++
 4 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/core/org.eclipse.cdt.core/.settings/.api_filters b/core/org.eclipse.cdt.core/.settings/.api_filters
index dda81c3a1bc..51035270037 100644
--- a/core/org.eclipse.cdt.core/.settings/.api_filters
+++ b/core/org.eclipse.cdt.core/.settings/.api_filters
@@ -1,6 +1,12 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <component id="org.eclipse.cdt.core" version="2">
     <resource path="utils/org/eclipse/cdt/utils/debug/dwarf/DwarfConstants.java" type="org.eclipse.cdt.utils.debug.dwarf.DwarfConstants">
+        <filter id="336658481">
+            <message_arguments>
+                <message_argument value="org.eclipse.cdt.utils.debug.dwarf.DwarfConstants"/>
+                <message_argument value="DW_FORM_implicit_const"/>
+            </message_arguments>
+        </filter>
         <filter id="336658481">
             <message_arguments>
                 <message_argument value="org.eclipse.cdt.utils.debug.dwarf.DwarfConstants"/>
diff --git a/core/org.eclipse.cdt.core/META-INF/MANIFEST.MF b/core/org.eclipse.cdt.core/META-INF/MANIFEST.MF
index 82693b61112..8d1303efaa9 100644
--- a/core/org.eclipse.cdt.core/META-INF/MANIFEST.MF
+++ b/core/org.eclipse.cdt.core/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.cdt.core; singleton:=true
-Bundle-Version: 8.2.200.qualifier
+Bundle-Version: 8.3.0.qualifier
 Bundle-Activator: org.eclipse.cdt.core.CCorePlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
diff --git a/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/Dwarf.java b/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/Dwarf.java
index 8750f348af2..fca32d3f41c 100644
--- a/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/Dwarf.java
+++ b/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/Dwarf.java
@@ -13,6 +13,7 @@
  *     Salvatore Culcasi - Bug 322475
  *     Serge Beauchamp - Bug 409916
  *     John Dallaway - Support DW_FORM_line_strp (#198)
+ *     John Dallaway - Support DW_FORM_implicit_const (#443)
  *******************************************************************************/
 
 package org.eclipse.cdt.utils.debug.dwarf;
@@ -109,17 +110,21 @@ class Attribute {
 		long name;
 		/* unsigned */
 		long form;
+		/* signed (for DW_FORM_implicit_const) */
+		long value;
 
-		Attribute(long n, long f) {
+		Attribute(long n, long f, long v) {
 			name = n;
 			form = f;
+			value = v;
 		}
 
 		@Override
 		public String toString() {
 			StringBuilder sb = new StringBuilder();
 			sb.append("name: ").append(Long.toHexString(name)); //$NON-NLS-1$
-			sb.append(" value: ").append(Long.toHexString(form)); //$NON-NLS-1$
+			sb.append(" form: ").append(Long.toHexString(form)); //$NON-NLS-1$
+			sb.append(" value: ").append(Long.toHexString(value)); //$NON-NLS-1$
 			return sb.toString();
 		}
 	}
@@ -579,11 +584,17 @@ Map<Long, AbbreviationEntry> parseDebugAbbreviation(CompilationUnitHeader header
 					do {
 						name = read_unsigned_leb128(data);
 						form = read_unsigned_leb128(data);
+						long value = 0;
+						if (DwarfConstants.DW_FORM_implicit_const == form) {
+							value = read_signed_leb128(data);
+						}
 						if (name != 0) {
-							entry.attributes.add(new Attribute(name, form));
+							entry.attributes.add(new Attribute(name, form, value));
 						}
 						if (printEnabled)
-							System.out.println("\t\t " + Long.toHexString(name) + " " + Long.toHexString(form)); //$NON-NLS-1$ //$NON-NLS-2$
+							System.out.println("\t\t " + Long.toHexString(name) //$NON-NLS-1$
+									+ " " + Long.toHexString(form) //$NON-NLS-1$
+									+ " " + Long.toHexString(value)); //$NON-NLS-1$
 					} while (name != 0 && form != 0);
 					abbrevs.put(Long.valueOf(code), entry);
 				}
@@ -603,7 +614,12 @@ void parseDebugInfoEntry(IDebugEntryRequestor requestor, ByteBuffer in, Map<Long
 				try {
 					for (int i = 0; i < len; i++) {
 						Attribute attr = entry.attributes.get(i);
-						Object obj = readAttribute((int) attr.form, in, header);
+						Object obj;
+						if (DwarfConstants.DW_FORM_implicit_const == attr.form) {
+							obj = Long.valueOf(attr.value);
+						} else {
+							obj = readAttribute((int) attr.form, in, header);
+						}
 						list.add(new AttributeValue(attr, obj));
 					}
 				} catch (IOException e) {
diff --git a/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/DwarfConstants.java b/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/DwarfConstants.java
index 6508da7ff62..e1c62cf9a13 100644
--- a/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/DwarfConstants.java
+++ b/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/utils/debug/dwarf/DwarfConstants.java
@@ -11,6 +11,7 @@
  * Contributors:
  *     QNX Software Systems - Initial API and implementation
  *     John Dallaway - Add DW_FORM_line_strp (#198)
+ *     John Dallaway - Add DW_FORM_implicit_const (#443)
  *******************************************************************************/
 
 package org.eclipse.cdt.utils.debug.dwarf;
@@ -216,6 +217,10 @@ public class DwarfConstants {
 	 * @since 5.7
 	 */
 	public final static int DW_FORM_ref_sig8 = 0x20;
+	/**
+	 * @since 8.3
+	 */
+	public final static int DW_FORM_implicit_const = 0x21;
 	/* Extensions for Fission. See http://gcc.gnu.org/wiki/DebugFission. */
 	/**
 	 * @since 5.7