How to add new instruction with dexlib2?

[Modify]

I try to add new instruction,

// old

const/v4 v?, 0x0

// new

const/v4 v?, 0x0
const-string v?, "Hello" // new instruction

can someone help me, adding instruction without duplicate register number?

[CodeExplorer]

Look to these sample I've created DEXPatcher:
https://gitlab.com/CodeCracker/DEXPatcher
https://github.com/CodeCrackerSND/DEXPatcher
https://bitbucket.org/CodeCrackerSND/dexpatcher

More exactly look here:
https://gitlab.com/CodeCracker/DEXPatcher/blob/master/dexpatcher/DEXPatcher.java

 

Edited September 20, 2018 by CodeExplorer

[Modify]

@CodeExplorer

I try with this code:

private static MethodImplementation addNewInstructions(@Nonnull MethodImplementation implementation) {

		MutableMethodImplementation mutableImplementation = new MutableMethodImplementation(implementation);

		List<BuilderInstruction> instructions = mutableImplementation.getInstructions();
		
		for (int i = 0; i < instructions.size(); i++) {
			
			Instruction instruction = instructions.get(i);
			
			if (instruction instanceof ReferenceInstruction) {

				if (((ReferenceInstruction) instruction).getReferenceType() == ReferenceType.METHOD) {

					Opcode opcode = instruction.getOpcode();

					if (!opcode.name.endsWith("range")) {
						mutableImplementation.addInstruction(i++, new BuilderInstruction21c(Opcode.CONST_STRING,
								0, new ImmutableStringReference("Hello World"))); // look
					}
				}
			}
		}

		return mutableImplementation;
	}

after :

// before

.line 54
iget-object v0, p0, Lapp/test/MainActivity;->ed:Landroid/widget/TextView;


// after

.line 54
iget-object v0, p0, Lapp/test/MainActivity;->ed:Landroid/widget/TextView; // v0 already register

const-string v0, "Hello World" // v0 duplicate register

If i storing a new value in it, I'll be clobbering any value that was already there, and later code that expects the previous value will likely fail.

Edited September 20, 2018 by Modify