Re: [RFA]: Merge stack alignment branch

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, Apr 11, 2008 at 3:03 AM, Jan Hubicka <hubicka@ucw.cz> wrote:

>  Index: function.h
>  ===================================================================
>  --- function.h  (.../trunk/gcc) (revision 134098)
>  +++ function.h  (.../branches/stack/gcc)        (revision 134141)
>  @@ -352,9 +355,16 @@ struct function GTY(())
>    /* tm.h can use this to store whatever it likes.  */
>    struct machine_function * GTY ((maybe_undef)) machine;
>
>  -  /* The largest alignment of slot allocated on the stack.  */
>  +  /* The largest alignment needed on the stack, including requirement
>  +     for outgoing stack alignment.  */
>    unsigned int stack_alignment_needed;
>
>  +  /* The largest alignment of slot allocated on the stack.  */
>  +  unsigned int stack_alignment_used;
>  +
>  +  /* The estimated stack alignment.  */
>  +  unsigned int stack_alignment_estimated;
>  +
>    /* Preferred alignment of the end of stack frame.  */
>    unsigned int preferred_stack_boundary;
>
>  @@ -509,6 +519,38 @@ struct function GTY(())
>
>    /* Nonzero if pass_tree_profile was run on this function.  */
>    unsigned int after_tree_profile : 1;
>  +
>  +/* Nonzero if current function must be given a frame pointer.
>  +   Set in global.c if anything is allocated on the stack there.  */
>  +  unsigned int need_frame_pointer : 1;
>  +
>  +  /* Nonzero if need_frame_pointer has been set.  */
>  +  unsigned int need_frame_pointer_set : 1;
>  +
>  +  /* Nonzero if, by estimation, current function stack needs realignment. */
>  +  unsigned int stack_realign_needed : 1;
>  +
>  +  /* Nonzero if function stack realignment is really needed. This flag
>  +     will be set after reload if by then criteria of stack realignment
>  +     is still true. Its value may be contridition to stack_realign_needed
>  +     since the latter was set before reload. This flag is more accurate
>  +     than stack_realign_needed so prologue/epilogue should be generated
>  +     according to both flags  */
>  +  unsigned int stack_realign_really : 1;
>  +
>  +  /* Nonzero if function being compiled needs dynamic realigned
>  +     argument pointer (drap) if stack needs realigning.  */
>  +  unsigned int need_drap : 1;
>  +
>  +  /* Nonzero if current function needs to save/restore parameter
>  +     pointer register in prolog, because it is a callee save reg.  */
>  +  unsigned int save_param_ptr_reg : 1;
>  +
>  +  /* Nonzero if function stack realignment estimatoin is done.  */
>  +  unsigned int stack_realign_processed : 1;
>  +
>  +  /* Nonzero if function stack realignment has been finalized.  */
>  +  unsigned int stack_realign_finalized : 1;
>
>
>  As I've mentioned originally, it would be nice to place all the
>  variables and flags computed only at expansion time or later to
>  rtl_data.  I guess it covers majority of the above variables.
>
>  +#define frame_pointer_needed (cfun->need_frame_pointer)
>
>  It might be better to stick with the x_frame_pointer_needed accestor
>  scheme or simply replace it in sources with crtl->frame_pointer_needed
>  (I would definitly preffer the second)
>

They should stay with stack_alignment_needed and preferred_stack_boundary,
which are in "struct function". We can move those new stack alignment
fields to rtl_data when they are moved to rtl_data.

Thanks.


H.J.