Fix JimplePrinter escaping to work like (old) Soot

sootup.core/src/main/java/sootup/core/util/printer/AbstractStmtPrinter.java

@@ -128,7 +128,7 @@ public void typeSignature(@Nonnull Type type) {
         ((ArrayType) type).toString(this);
       } else {
         // primitive types: there should be no need to escape sth
-        output.append(type.toString());
+        output.append(type);
       }
     } else {
       output.append(Jimple.escape(type.toString()));

sootup.core/src/main/java/sootup/core/util/printer/JimplePrinter.java

@@ -238,17 +238,19 @@ private void printMethods(SootClass<?> cl, LabeledStmtPrinter printer, PrintWrit
       while (methodIt.hasNext()) {
         SootMethod method = (SootMethod) methodIt.next();
 
+        printer.handleIndent();
+        method.toString(printer);
+
         if (method.hasBody()) {
           Body body = method.getBody();
           // print method's full signature information
-          method.toString(printer);
           printer.newline();
+          incJimpleLnNum();
           printBody(body, printer);
 
         } else {
-          printer.handleIndent();
-          method.toString(printer);
           printer.literal(";");
+          printer.newline();
           incJimpleLnNum();
         }
 
@@ -323,6 +325,7 @@ private void printStmts(StmtGraph<?> stmtGraph, LabeledStmtPrinter printer) {
 
     final Map<Stmt, String> labels = printer.getLabels();
     for (Stmt currentStmt : linearizedStmtGraph) {
+      if (currentStmt == null) continue;
       previousStmt = currentStmt;
 
       // Print appropriate header.

sootup.core/src/main/java/sootup/core/util/printer/LegacyJimplePrinter.java

@@ -22,8 +22,14 @@
  * #L%
  */
 
+import com.google.common.collect.ImmutableSet;
+import java.util.Set;
+import javax.annotation.Nonnull;
 import sootup.core.jimple.common.stmt.Stmt;
 import sootup.core.jimple.javabytecode.stmt.JSwitchStmt;
+import sootup.core.types.ClassType;
+import sootup.core.types.Type;
+import sootup.core.util.StringTools;
 
 /**
  * StmtPrinter implementation for normal (full) Jimple for OldSoot
@@ -35,10 +41,82 @@
  */
 public class LegacyJimplePrinter extends NormalStmtPrinter {
 
+  // source:
+  // https://github.com/soot-oss/soot/blob/1ad74494974165e8b5f2286c90f218a00eadc243/eclipse/ca.mcgill.sable.soot/src/ca/mcgill/sable/soot/editors/JimpleScanner.java
+  Set<String> soot_jimple_keywords =
+      ImmutableSet.of(
+          "ignored",
+          "abstract",
+          "final",
+          "native",
+          "public",
+          "protected",
+          "private",
+          "static",
+          "synchronized",
+          "transient",
+          "volatile",
+          "class",
+          "interface",
+          "void",
+          "boolean",
+          "byte",
+          "short",
+          "char",
+          "int",
+          "long",
+          "float",
+          "double",
+          "null_type",
+          "unknown",
+          "extends",
+          "implements",
+          "breakpoint",
+          "case",
+          "catch",
+          "cmp",
+          "cmpg",
+          "cmpl",
+          "default",
+          "entermonitor",
+          "exitmonitor",
+          "goto",
+          "if",
+          "instanceof",
+          "interfaceinvoke",
+          "lengthof",
+          "lookupswitch",
+          "neg",
+          "new",
+          "newarray",
+          "newmultiarray",
+          "nop",
+          "ret",
+          "return",
+          "specialinvoke",
+          "staticinvoke",
+          "tableswitch",
+          "throw",
+          "throws",
+          "virtualinvoke",
+          "null",
+          "from",
+          "to",
+          "with",
+          "annotation",
+          "enum");
+
   public LegacyJimplePrinter() {
     super();
   }
 
+  String sootEscape(String str) {
+    if (str.length() == 0) {
+      return "''";
+    }
+    return StringTools.getQuotedStringOf(str, soot_jimple_keywords.contains(str));
+  }
+
   @Override
   void enableImports(boolean enable) {
     if (enable) {
@@ -47,6 +125,27 @@ void enableImports(boolean enable) {
     }
   }
 
+  @Override
+  public void typeSignature(@Nonnull Type type) {
+    handleIndent();
+    if (type instanceof ClassType) {
+      ClassType ctype = (ClassType) type;
+      final String[] splits = ctype.getPackageName().getPackageName().split("\\.");
+      for (String split : splits) {
+        if (split.length() == 0) {
+          continue;
+        }
+        output.append(sootEscape(split));
+        output.append(".");
+      }
+      output.append(sootEscape(ctype.getClassName()));
+
+    } else {
+      // primitivetypes
+      output.append(type);
+    }
+  }
+
   @Override
   public void stmt(Stmt currentStmt) {
     startStmt(currentStmt);

sootup.java.core/src/test/java/sootup/java/core/printer/LegacyJimplePrinterTest.java

@@ -29,14 +29,18 @@
 public class LegacyJimplePrinterTest {
 
   SootClass buildClass(Body.BodyBuilder builder) {
+    return buildClass(builder, "dummyMain", "main");
+  }
+
+  SootClass buildClass(Body.BodyBuilder builder, String className, String methodName) {
 
     Project project =
         JavaProject.builder(new JavaLanguage(8)).addInputLocation(new EagerInputLocation()).build();
     View view = project.createView();
 
     MethodSignature methodSignature =
         view.getIdentifierFactory()
-            .getMethodSignature("main", "dummyMain", "void", Collections.emptyList());
+            .getMethodSignature(methodName, className, "void", Collections.emptyList());
     Body body =
         builder
             .setMethodSignature(methodSignature)
@@ -63,7 +67,7 @@ SootClass buildClass(Body.BodyBuilder builder) {
             null,
             null,
             null,
-            view.getIdentifierFactory().getClassType("dummyMain"),
+            view.getIdentifierFactory().getClassType(className),
             new EagerInputLocation()),
         SourceType.Application);
   }
@@ -157,4 +161,17 @@ public void testValidOptions() {
         new JimplePrinter(JimplePrinter.Option.UseImports, JimplePrinter.Option.LegacyMode);
     p.printTo(buildClass(Body.builder()), new PrintWriter(new StringWriter()));
   }
+
+  @Test
+  public void testLegacyEscaping() {
+    StringWriter out = new StringWriter();
+    PrintWriter writer = new PrintWriter(out);
+    JimplePrinter printer = new JimplePrinter(JimplePrinter.Option.LegacyMode);
+
+    SootClass clazz = buildClass(Body.builder(), "dummyMain", "from");
+    printer.printTo(clazz, writer);
+    String jimple = out.toString();
+    assertEquals("public class dummyMain\n{\n    public static void \'from\'()\n    {\n    }\n}\n\r\n", jimple);
+  }
+
 }