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List:       linux-sparse
Subject:    Re: Query regarding sizeof long
From:       Luc Van Oostenryck <luc.vanoostenryck () gmail ! com>
Date:       2017-01-24 18:00:03
Message-ID: CAMHZB6EB31xGf6C-j=x0MpPnKjyap5Hb7P5BJd1V5DsycT92DA () mail ! gmail ! com
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On Tue, Jan 24, 2017 at 4:08 PM, Dibyendu Majumdar
<mobile@majumdar.org.uk> wrote:
> Hi Luc,
>
> On 24 January 2017 at 14:47, Luc Van Oostenryck
> <luc.vanoostenryck@gmail.com> wrote:
>> On Tue, Jan 24, 2017 at 02:23:13PM +0000, Dibyendu Majumdar wrote:
>>> I am working on porting Sparse to Windows, and I noticed that in
>>> 64-bit architecture the bits_in_long is set to 64. This is not true
>>> for Windows where long is 32 bits on a 64-bit machine. I was wondering
>>> if I just need to set this parameter to 32 or if there are other
>>> implications that I need to be aware of.
>>
>> If you just change the initial value in target.c, it won't do what you
>> need because currently, if you compile sparse on a machine where
>> __x86_64__ is defined, it will automatically enable the -m64 option
>> which will setup things for an LP64 architecture instead of the LLP64
>> that you need (inside handle_arch_m64_finalize()).
>>
>
> Yes I noticed that and I can easily make that conditional on MSVC. I
> guess my question is more whether there are any assumptions in the
> code that a long in a 64-bit environment is 64-bits (e.g. pointers fit
> into long). I have not yet been able to run all the tests on Windows,
> but I guess that is one way I can find out if there are any issues.

There shouldn't be any such assumptions :)
And I think, you shouldn't have much bad surprised,
but I'm a bit less confident regarding the test-suite. It's very possible
that some tests have the assumption that sizeof(long) == sizeof(pointer).
And I'm pretty sure that this LLP64 situation have been very little tested,
very possibly never been tested at all.

Luc
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