Re: Changing the word-size was: Re: eat your own dog food?

[jamal <hadi-fAAogVwAN2Kw5LPnMra/2Q@public.gmane.org>]

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On Sat, 2008-12-01 at 15:28 -0200, Arnaldo Carvalho de Melo wrote:

> Now what seems to be the last thing to do is to follow typedefs and find
> unnamed structs, think about spinlock_t, socket_lock_t, etc.
> 

Good stuff Arnaldo - updated local tree. 
I should be able to test later today.

Dont know much about cmake, is it possible to check for elfutils version
and not depend on build_id if version < xxx?
This way i dont have to go out of my way to maintain my own versions of
elf utilities. I have to do the patch you sent earlier manually now. I
will remove it if you will fix cmake.

BTW, while perusing archs i managed i think to gather sufficiently
accurate info (;->) on the different alignments; i got lazy at the end,
but quiet a few are in the attached txt file incase you find them
useful. Double check sparc for example. I think most 64-bit hardware
looks consistent; the funnies are in 32-bit archs.

cheers,
jamal

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		MIPS EABI
			=========

Sizes and alignments
--------------------

	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long		4		4 (32-bit mode)
			8		8 (64-bit mode)
	long long	8		8
	float		4		4
	double		8		8
	pointers	4		4 (32-bit mode)
			8		8 (64-bit mode)

* alignment within aggregates (structs and unions) is as above, with
  padding added if needed
* aggregates have alignment equal to that of their most aligned
  member
* aggregates have sizes which are a multiple of their alignment

ia32 Sizes and alignments
--------------------

	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long		4		4 
	long long	8		4
	float		4		4
	double		8		4
	pointers	4		4 

* alignment within aggregates (structs and unions) is as above, with
  padding added if needed
* aggregates have alignment equal to that of their most aligned
  member
* aggregates have sizes which are a multiple of their alignment
  This may result in tail padding.

ia64 Sizes and alignments
--------------------

	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long		8		8 
	long long	8		8
	float		4		4
	double		8		8
	pointers	8		8 

    * An entire structure or union object shall be aligned on the same 
      boundary as its most strictly aligned member.
    * Each member shall be assigned to the lowest available offset with the 
      appropriate alignment. This may require internal padding, depending 
      on the previous member.
    * A structure's size shall be increased, if necessary, to make it a 
      multiple of the alignment. This may require tail padding, depending 
      on the last member. 

AMD 64
-------


	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long		4		4 
			8		8 (64-bit mode)
	long long	8		4
			8		8 (64-bit mode)
	float		4		4
	double		8		4
	pointers	4		4 
			8		8 (64-bit mode)

powerpc - 32bit

	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long	        4		4
	long long	8		8
	float		4		4
	double		8		8
	long double	16		16
	pointers	4		4 

powerpc - 64bit
	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long	        8		8
	long long	8		8
	int128  	16		16
	float		4		4
	double		8		8
	long double	16		16
	pointers	8		8 


sparc:
	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long	        4		4
	long long	8		8
	float		4		4
	double		8		8
	long double	16		8
	pointers	4		4 


s390:
------
	Type		Size (bytes)	Alignment (bytes)

	char		1		1
	short		2		2
	int		4		4
	unsigned	4		4
	long	        4		4
	long long	8		8
	float		4		4
	double		8		8
	long double	16		16
	pointers	4		4 

s390-zseries
---------