Re: [Qemu-devel] scripts/gdb: Fix a python exception in mtree.py

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Wed, Dec 02, 2015 at 03:56:24PM +0800, Yang Wei wrote:
> The following exception is threw:
> Python Exception <class 'NameError'> name 'long' is not defined:
> Error occurred in Python command: name 'long' is not defined
> 
> In python3, long is rename to int
> 
> Signed-off-by: Yang Wei <w90p710@gmail.com>
> ---
>  scripts/qemugdb/mtree.py | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)

Even in Python 2.4+, int()/long() have been unified to an extent:
https://www.python.org/dev/peps/pep-0237/
https://docs.python.org/2/whatsnew/2.4.html

If the value is too large for the int() constructor, it returns a
long().

Can this patch be simplified to s/\<int\>/long/g ?

That way no Python version checks are necessary.

> diff --git a/scripts/qemugdb/mtree.py b/scripts/qemugdb/mtree.py
> index 06011c3..460d4b6 100644
> --- a/scripts/qemugdb/mtree.py
> +++ b/scripts/qemugdb/mtree.py
> @@ -16,12 +16,19 @@
>  # 'qemu mtree' -- display the memory hierarchy
>  
>  import gdb
> +import sys
>  
>  def isnull(ptr):
>      return ptr == gdb.Value(0).cast(ptr.type)
>  
> +# PEP 0237: long renamed to int. That is, there is only one built-integral
> +# integral type, named int; but it behaves mostly like the old long type.
> +# https://docs.python.org/3.3/whatsnew/3.0.html#integers
> +def intptr(p):
> +    return long(p) if sys.version_info.major == 2 else int(p)
> +
>  def int128(p):
> -    return long(p['lo']) + (long(p['hi']) << 64)
> +    return intptr(p['lo']) + (intptr(p['hi']) << 64)
>  
>  class MtreeCommand(gdb.Command):
>      '''Display the memory tree hierarchy'''
> @@ -40,11 +47,11 @@ class MtreeCommand(gdb.Command):
>      def process_queue(self):
>          while self.queue:
>              ptr = self.queue.pop(0)
> -            if long(ptr) in self.seen:
> +            if intptr(ptr) in self.seen:
>                  continue
>              self.print_item(ptr)
>      def print_item(self, ptr, offset = gdb.Value(0), level = 0):
> -        self.seen.add(long(ptr))
> +        self.seen.add(intptr(ptr))
>          addr = ptr['addr']
>          addr += offset
>          size = int128(ptr['size'])
> @@ -58,8 +65,8 @@ class MtreeCommand(gdb.Command):
>              klass = ' (RAM)'
>          gdb.write('%s%016x-%016x %s%s (@ %s)\n'
>                    % ('  ' * level,
> -                     long(addr),
> -                     long(addr + (size - 1)),
> +                     intptr(addr),
> +                     intptr(addr + (size - 1)),
>                       ptr['name'].string(),
>                       klass,
>                       ptr,
> -- 
> 1.9.1
> 
> 

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