8034066: Incorrect alignment in the "Code" section for "-c -XDdetails" options

Reviewed-by: jvernee, liach

src/jdk.jdeps/share/classes/com/sun/tools/javap/ClassWriter.java

@@ -576,9 +576,7 @@ public class ClassWriter extends BasicWriter {
             attrWriter.write(m.attributes());
         } else if (code != null) {
             if (options.showDisassembled) {
-                println("Code:");
-                codeWriter.writeInstrs(code);
-                codeWriter.writeExceptionTable(code);
+                codeWriter.writeMinimal(code);
             }
 
             if (options.showLineAndLocalVariableTables) {

src/jdk.jdeps/share/classes/com/sun/tools/javap/CodeWriter.java

@@ -70,13 +70,11 @@ public class CodeWriter extends BasicWriter {
     }
 
     void write(CodeAttribute attr) {
-        println("Code:");
-        indent(+1);
-        writeVerboseHeader(attr);
-        writeInstrs(attr);
-        writeExceptionTable(attr);
-        attrWriter.write(attr.attributes(), attr);
-        indent(-1);
+        writeInternal(attr, false);
+    }
+
+    void writeMinimal(CodeAttribute attr) {
+        writeInternal(attr, true);
     }
 
     public void writeVerboseHeader(CodeAttribute attr) {
@@ -259,6 +257,20 @@ public class CodeWriter extends BasicWriter {
         return detailWriters;
     }
 
+    private void writeInternal(CodeAttribute attr, boolean minimal) {
+        println("Code:");
+        indent(+1);
+        if (!minimal) {
+            writeVerboseHeader(attr);
+        }
+        writeInstrs(attr);
+        writeExceptionTable(attr);
+        if (!minimal) {
+            attrWriter.write(attr.attributes(), attr);
+        }
+        indent(-1);
+    }
+
     private AttributeWriter attrWriter;
     private ClassWriter classWriter;
     private ConstantWriter constantWriter;

test/langtools/tools/javap/ClassWriterCodeIndentTest.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2024, Oracle and/or its affiliates. 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 8034066
+ * @summary javap incorrect indentation when CodeWriter called via ClassWriter
+ * @run main ClassWriterCodeIndentTest
+ * @modules jdk.jdeps/com.sun.tools.javap
+ */
+
+import java.io.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ClassWriterCodeIndentTest {
+    public static void main(String[] args) {
+        new ClassWriterCodeIndentTest().run();
+    }
+
+    public void run() {
+        /*
+         * Partial expected output within a larger file. There exists another "Code: " section above, and thus we
+         * select the second occurrence in `findNthMatchPrecedingSpaces(output, "Code:", 1);`
+         * ...
+         *    Code:
+         *         0: iconst_0
+         *         1: istore_1
+         *      StackMap locals:  this int
+         *      StackMap stack:
+         * ...
+         */
+        String output = javap();
+
+        int codeHeaderIndent = findNthMatchPrecedingSpaces(output, "Code:", 1);
+        int detailIndent = findNthMatchPrecedingSpaces(output, "StackMap ", 0);
+        int bytecodeIndent = findNthMatchPrecedingSpaces(output, "0: iconst_0", 0);
+
+        if (detailIndent - codeHeaderIndent != 2) {
+            error("Details are not indented correctly with respect to code header.");
+        }
+
+        if (bytecodeIndent - codeHeaderIndent != 5) {
+            error("Bytecode is not indented correctly with respect to code header.");
+        }
+
+        if (errors > 0) {
+            throw new Error(errors + " found.");
+        }
+    }
+
+    String javap() {
+        StringWriter sw = new StringWriter();
+        PrintWriter out = new PrintWriter(sw);
+        int rc = com.sun.tools.javap.Main.run(new String[]{"-c", "-XDdetails:stackMaps",
+            System.getProperty("test.classes") + "/EmptyLoop.class"}, out);
+        if (rc != 0)
+            throw new Error("javap failed. rc=" + rc);
+        out.close();
+        System.out.println(sw.toString());
+        return sw.toString();
+    }
+
+    public static int findNthMatchPrecedingSpaces(String inputString, String searchString, int occurrence) {
+        String regex = "^(\\s*)" + Pattern.quote(searchString);
+        Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
+        Matcher matcher = pattern.matcher(inputString);
+
+        int count = 0;
+        while (matcher.find()) {
+            if (count == occurrence) {
+                return matcher.group(1).length();
+            }
+            count++;
+        }
+
+        throw new Error("Could not find " + searchString + " in " + inputString);
+    }
+
+    void error(String msg) {
+        System.err.println(msg);
+        errors++;
+    }
+
+    int errors;
+}
+
+class EmptyLoop {
+    public void emptyLoop() {
+        for (int i = 0; i < 10; i++) {
+        }
+    }
+}