feat: added BytecodePrinter

1 files changed, 79 insertions, 0 deletions

diff --git a/src/main/java/ftbsc/lll/tools/debug/BytecodePrinter.java b/src/main/java/ftbsc/lll/tools/debug/BytecodePrinter.java
new file mode 100644
index 0000000..cf253c9
--- /dev/null
+++ b/src/main/java/ftbsc/lll/tools/debug/BytecodePrinter.java
@@ -0,0 +1,79 @@
+package ftbsc.lll.tools.debug;
+
+import org.apache.logging.log4j.Logger;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.util.Printer;
+import org.objectweb.asm.util.Textifier;
+import org.objectweb.asm.util.TraceMethodVisitor;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+/**
+ * A collection of static methods for debugging by printing the ASM bytecode.
+ * These methods are only for debug, so most of the time they should stay unused.
+ */
+public class BytecodePrinter {
+
+	/**
+	 * Used for converting visit events to text, acts pretty much like a buffer in our case.
+	 */
+	private static final Printer PRINTER = new Textifier();
+
+	/**
+	 * MethodVisitor that visits the method and prints it to a given printer.
+	 */
+	private static final TraceMethodVisitor MP = new TraceMethodVisitor(PRINTER);
+
+	/**
+	 * Prints the bytecode of a method using System.out.print().
+	 * @param main the method to print
+	 */
+	public static void printAsmMethod(final MethodNode main) {
+		for (AbstractInsnNode i : main.instructions.toArray())
+			System.out.print(insnToString(i));
+	}
+
+	/**
+	 * Logs the bytecode of a method using the ASM logger.
+	 * @param main the method to print
+	 * @param logger the Log4j logger to print it with
+	 */
+	public static void logAsmMethod(final MethodNode main, final Logger logger) {
+		for (AbstractInsnNode i : main.instructions.toArray())
+			logger.debug(insnToString(i));
+	}
+
+	/**
+	 * Logs the bytecode of a method to a file.
+	 * @param main the method to print
+	 * @param path the file to log it to
+	 */
+	public static void logAsmMethod(final MethodNode main, String path) {
+		StringBuilder out = new StringBuilder();
+		for (AbstractInsnNode i : main.instructions.toArray())
+			out.append(insnToString(i));
+		try {
+			Files.write(Paths.get(path), out.toString().getBytes());
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+	}
+
+	/**
+	 * Converts an instruction node to a String.
+	 * @param insn the node to convert
+	 * @return the converted string
+	 */
+	public static String insnToString(AbstractInsnNode insn) {
+		insn.accept(MP);
+		StringWriter sw = new StringWriter();
+		PRINTER.print(new PrintWriter(sw));
+		PRINTER.getText().clear();
+		return sw.toString();
+	}
+}
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