Advertisements I’m implementing a deferred refinement operation for my numerical static analysis framework, specifically, integers and longs. For reference, int (and smaller) can be compared directly, no need for a cmp operation. However, I have noticed that the bytecode generated (at least for Java 11 targeting 1.8) for binary comparisons flips the comparison operation. For… Read More Why does Java Compiler flip relational comparisons between primitive types? `i < j` => `i >= j`

Advertisements I want to edit a jar file, with byte code, and i created a project to edit it. I have 2 functions : public static byte[] transform(byte[] buf){ ClassNode classNode = new ClassNode(); ClassReader classReader = new ClassReader(buf); classReader.accept(classNode, ClassReader.EXPAND_FRAMES); for (MethodNode method : classNode.methods) { if(method.name.equals(shouldSideBeRenderedMethod) && method.desc.startsWith("(L") && method.desc.endsWith(";IIII)Z")){ System.out.println("[*] Patching bytecode… Read More Class compiled by a more recent version of the Java Runtime (0.0), this version of the Java Runtime only recognizes class file versions up to 52.0

Advertisements In gcc you can use -S to stop compilation after your code has been compiled into assembly. Is there a similar feature with Python/bytecode? I know of ways like: import dis x = compile(‘print(1)’, ”, ‘eval’) dis.dis(x) Which prints: 1 0 LOAD_NAME 0 (print) 2 LOAD_CONST 0 (1) 4 CALL_FUNCTION 1 6 RETURN_VALUE But… Read More Disassemble a Python script from the command line?