void putVar(LocalVar var) {
        if (!varDebugInfo) return;
        if ((var.sym.flags() & Flags.SYNTHETIC) != 0) return;
        if (varBuffer == null)
            varBuffer = new LocalVar[20];
        else if (varBufferSize >= varBuffer.length) {
            LocalVar[] newVarBuffer = new LocalVar[varBufferSize*2];
            System.arraycopy(varBuffer, 0, newVarBuffer, 0, varBuffer.length);
            varBuffer = newVarBuffer;
        }
        varBuffer[varBufferSize++] = var;
    }