Examples with Label org.jf.dexlib2.builder.Label used on opensource projects

Example 16 with Label

use of org.jf.dexlib2.builder.Label in project soot by Sable.

the class DexPrinter method insertIntermediateJump.

/**
 * Creates an intermediate jump instruction between the original jump
 * instruction and its target
 *
 * @param targetInsPos
 *            The jump target index
 * @param jumpInsPos
 *            The position of the jump instruction
 * @param stmtV
 *            The statement visitor used for constructing the instructions
 * @param instructions
 *            The list of Dalvik instructions
 * @param labelAssigner
 *            The label assigner to be used for creating new labels
 */
private void insertIntermediateJump(int targetInsPos, int jumpInsPos, StmtVisitor stmtV, List<BuilderInstruction> instructions, LabelAssigner labelAssigner) {
    // Get the original jump instruction
    BuilderInstruction originalJumpInstruction = instructions.get(jumpInsPos);
    Insn originalJumpInsn = stmtV.getInsnForInstruction(originalJumpInstruction);
    if (originalJumpInsn == null)
        return;
    if (!(originalJumpInsn instanceof InsnWithOffset))
        throw new RuntimeException("Unexpected jump instruction target");
    InsnWithOffset offsetInsn = (InsnWithOffset) originalJumpInsn;
    // If this is goto instruction, we can just replace it
    if (originalJumpInsn instanceof Insn10t) {
        if (originalJumpInsn.getOpcode() == Opcode.GOTO) {
            Insn30t newJump = new Insn30t(Opcode.GOTO_32);
            newJump.setTarget(((Insn10t) originalJumpInsn).getTarget());
            BuilderInstruction newJumpInstruction = newJump.getRealInsn(labelAssigner);
            instructions.remove(jumpInsPos);
            instructions.add(jumpInsPos, newJumpInstruction);
            stmtV.fakeNewInsn(stmtV.getStmtForInstruction(originalJumpInstruction), newJump, newJumpInstruction);
            return;
        }
    }
    // Find a position where we can jump to
    int distance = Math.max(targetInsPos, jumpInsPos) - Math.min(targetInsPos, jumpInsPos);
    if (distance == 0)
        return;
    int newJumpIdx = Math.min(targetInsPos, jumpInsPos) + (distance / 2);
    int sign = (int) Math.signum(targetInsPos - jumpInsPos);
    // label may otherwise be attached to the wrong statement
    do {
        Stmt newStmt = stmtV.getStmtForInstruction(instructions.get(newJumpIdx));
        Stmt prevStmt = newJumpIdx > 0 ? stmtV.getStmtForInstruction(instructions.get(newJumpIdx - 1)) : null;
        if (newStmt == null || newStmt == prevStmt) {
            newJumpIdx -= sign;
            if (newJumpIdx < 0 || newJumpIdx >= instructions.size())
                throw new RuntimeException("No position for inserting intermediate " + "jump instruction found");
        } else
            break;
    } while (true);
    // Create a jump instruction from the middle to the end
    NopStmt nop = Jimple.v().newNopStmt();
    Insn30t newJump = new Insn30t(Opcode.GOTO_32);
    newJump.setTarget(stmtV.getStmtForInstruction(instructions.get(targetInsPos)));
    BuilderInstruction newJumpInstruction = newJump.getRealInsn(labelAssigner);
    instructions.add(newJumpIdx, newJumpInstruction);
    stmtV.fakeNewInsn(nop, newJump, newJumpInstruction);
    // We have added something, so we need to fix indices
    if (newJumpIdx <= jumpInsPos)
        jumpInsPos++;
    if (newJumpIdx <= targetInsPos)
        targetInsPos++;
    // Jump from the original instruction to the new one in the middle
    offsetInsn.setTarget(nop);
    BuilderInstruction replacementJumpInstruction = offsetInsn.getRealInsn(labelAssigner);
    assert instructions.get(jumpInsPos) == originalJumpInstruction;
    instructions.remove(jumpInsPos);
    instructions.add(jumpInsPos, replacementJumpInstruction);
    stmtV.fakeNewInsn(stmtV.getStmtForInstruction(originalJumpInstruction), originalJumpInsn, replacementJumpInstruction);
    // Our indices are still fine, because we just replaced something
    Stmt afterNewJump = stmtV.getStmtForInstruction(instructions.get(newJumpIdx + 1));
    // Make the original control flow jump around the new artificial jump
    // instruction
    Insn10t jumpAround = new Insn10t(Opcode.GOTO);
    jumpAround.setTarget(afterNewJump);
    BuilderInstruction jumpAroundInstruction = jumpAround.getRealInsn(labelAssigner);
    instructions.add(newJumpIdx, jumpAroundInstruction);
    stmtV.fakeNewInsn(Jimple.v().newNopStmt(), jumpAround, jumpAroundInstruction);
}

Example 17 with Label

use of org.jf.dexlib2.builder.Label in project soot by Sable.

the class DexPrinter method fixLongJumps.

/**
 * Fixes long jumps that exceed the maximum distance for the respective jump
 * type
 *
 * @param instructions
 *            The list of generated dalvik instructions
 * @param labelAssigner
 *            The label assigner that maps statements to labels
 * @param stmtV
 *            The statement visitor used to produce the dalvik instructions
 */
private void fixLongJumps(List<BuilderInstruction> instructions, LabelAssigner labelAssigner, StmtVisitor stmtV) {
    // Only construct the maps once and update them afterwards
    Map<Instruction, Integer> instructionsToIndex = new HashMap<Instruction, Integer>();
    List<Integer> instructionsToOffsets = new ArrayList<Integer>();
    Map<Label, Integer> labelsToOffsets = new HashMap<Label, Integer>();
    Map<Label, Integer> labelsToIndex = new HashMap<Label, Integer>();
    boolean hasChanged;
    l0: do {
        // Look for changes anew every time
        hasChanged = false;
        instructionsToOffsets.clear();
        // Build a mapping between instructions and offsets
        {
            int offset = 0;
            int idx = 0;
            for (BuilderInstruction bi : instructions) {
                instructionsToIndex.put(bi, idx);
                instructionsToOffsets.add(offset);
                Stmt origStmt = stmtV.getStmtForInstruction(bi);
                if (origStmt != null) {
                    Label lbl = labelAssigner.getLabelUnsafe(origStmt);
                    if (lbl != null) {
                        labelsToOffsets.put(lbl, offset);
                        labelsToIndex.put(lbl, idx);
                    }
                }
                offset += (bi.getFormat().size / 2);
                idx++;
            }
        }
        // Look for references to labels
        for (int j = 0; j < instructions.size(); j++) {
            BuilderInstruction bj = instructions.get(j);
            if (bj instanceof BuilderOffsetInstruction) {
                BuilderOffsetInstruction boj = (BuilderOffsetInstruction) bj;
                // Compute the distance between the instructions
                Insn jumpInsn = stmtV.getInsnForInstruction(boj);
                if (jumpInsn instanceof InsnWithOffset) {
                    InsnWithOffset offsetInsn = (InsnWithOffset) jumpInsn;
                    Integer targetOffset = labelsToOffsets.get(boj.getTarget());
                    if (targetOffset == null)
                        continue;
                    int distance = instructionsToOffsets.get(j) - targetOffset;
                    if (Math.abs(distance) > offsetInsn.getMaxJumpOffset()) {
                        // We need intermediate jumps
                        insertIntermediateJump(labelsToIndex.get(boj.getTarget()), j, stmtV, instructions, labelAssigner);
                        hasChanged = true;
                        continue l0;
                    }
                }
            }
        }
    } while (hasChanged);
}