Exemple #1
0
  /**
   * Rewrites a move instruction if it has 2 memory operands. One of the 2 memory operands must be a
   * stack location operand. Move the SP to the appropriate location and use a push or pop
   * instruction.
   *
   * @param s the instruction to rewrite
   */
  private void rewriteMoveInstruction(Instruction s) {
    // first attempt to mutate the move into a noop
    if (mutateMoveToNop(s)) return;

    Operand result = MIR_Move.getResult(s);
    Operand val = MIR_Move.getValue(s);
    if (result instanceof StackLocationOperand) {
      if (val instanceof MemoryOperand || val instanceof StackLocationOperand) {
        int offset = ((StackLocationOperand) result).getOffset();
        byte size = ((StackLocationOperand) result).getSize();
        offset = FPOffset2SPOffset(offset) + size;
        moveESPBefore(s, offset);
        MIR_UnaryNoRes.mutate(s, IA32_PUSH, val);
      }
    } else {
      if (result instanceof MemoryOperand) {
        if (val instanceof StackLocationOperand) {
          int offset = ((StackLocationOperand) val).getOffset();
          offset = FPOffset2SPOffset(offset);
          moveESPBefore(s, offset);
          MIR_Nullary.mutate(s, IA32_POP, result);
        }
      }
    }
  }
  /**
   * expand an FCLEAR pseudo-insruction using FFREEs.
   *
   * @param s the instruction to expand
   * @param ir the containing IR
   */
  private static void expandFClear(Instruction s, IR ir) {
    int nSave = MIR_UnaryNoRes.getVal(s).asIntConstant().value;
    int fpStackHeight = ir.MIRInfo.fpStackHeight;
    PhysicalRegisterSet phys = ir.regpool.getPhysicalRegisterSet().asIA32();

    for (int i = nSave; i < fpStackHeight; i++) {
      Register f = phys.getFPR(i);
      s.insertBefore(MIR_Nullary.create(IA32_FFREE, D(f)));
    }

    // Remove the FCLEAR.
    s.remove();
  }
Exemple #3
0
  /**
   * Insert the epilogue before a particular return instruction.
   *
   * @param ret the return instruction.
   */
  private void insertEpilogue(Instruction ret) {
    // 1. Restore any saved registers
    if (ir.compiledMethod.isSaveVolatile()) {
      restoreVolatileRegisters(ret);
      restoreFloatingPointState(ret);
    }
    restoreNonVolatiles(ret);

    // 2. Restore caller's stackpointer and framepointer
    int frameSize = getFrameFixedSize();
    ret.insertBefore(MIR_UnaryNoRes.create(REQUIRE_ESP, IC(frameSize)));
    MemoryOperand fpHome =
        MemoryOperand.BD(
            ir.regpool.makeTROp(),
            ArchEntrypoints.framePointerField.getOffset(),
            (byte) WORDSIZE,
            null,
            null);
    ret.insertBefore(MIR_Nullary.create(IA32_POP, fpHome));
  }