Re: RFA: frame id enhancement

[Andrew Cagney <ac131313@redhat.com>]

> Is the revised attached patch ok?

Yep, now I understand it.  Thanks.

Andrew

ex: frame.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/frame.h,v
> retrieving revision 1.110
> diff -u -r1.110 frame.h
> --- frame.h	10 Oct 2003 00:32:04 -0000	1.110
> +++ frame.h	16 Oct 2003 23:30:50 -0000
> @@ -95,8 +95,6 @@
>       is used.  Watch out for all the legacy targets that still use the
>       function pointer register or stack pointer register.  They are
>       wrong.  */
> -  /* NOTE: cagney/2002-11-16: The ia64 has two stacks and hence two
> -     frame bases.  This will need to be expanded to accomodate that.  */
>    CORE_ADDR stack_addr;
>    /* The frame's code address.  This shall be constant through out the
>       lifetime of the frame.  While the PC (a.k.a. resume address)
> @@ -104,15 +102,33 @@
>       Typically, it is set to the address of the entry point of the
>       frame's function (as returned by frame_func_unwind().  */
>    CORE_ADDR code_addr;
> +  /* The frame's special address.  This shall be constant through out the
> +     lifetime of the frame.  This is used for architectures that may have
> +     frames that do not change the stack but are still distinct and have 
> +     some form of distinct identifier (e.g. the ia64 which uses a 2nd 
> +     stack for registers).  This field is treated as unordered - i.e. will
> +     not be used in frame ordering comparisons such as frame_id_inner().
> +     A zero in this field will be treated as a wild-card when comparing
> +     frames for equality.  */
> +  CORE_ADDR special_addr;
>  };
>  
>  /* Methods for constructing and comparing Frame IDs.
>  
> -   NOTE: Given frameless functions A and B, where A calls B (and hence
> +   NOTE: Given stackless functions A and B, where A calls B (and hence
>     B is inner-to A).  The relationships: !eq(A,B); !eq(B,A);
> -   !inner(A,B); !inner(B,A); all hold.  This is because, while B is
> -   inner to A, B is not strictly inner to A (being frameless, they
> -   have the same .base value).  */
> +   !inner(A,B); !inner(B,A); all hold.
> +
> +   This is because, while B is inner-to A, B is not strictly inner-to A.  
> +   Being stackless, they have an identical .stack_addr value, and differ 
> +   only by their unordered .code_addr and/or .special_addr values.
> +
> +   Because frame_id_inner is only used as a safety net (e.g.,
> +   detect a corrupt stack) the lack of strictness is not a problem.
> +   Code needing to determine an exact relationship between two frames
> +   must instead use frame_id_eq and frame_id_unwind.  For instance,
> +   in the above, to determine that A stepped-into B, the equation
> +   "A.id != B.id && A.id == id_unwind (B)" can be used.  */
>  
>  /* For convenience.  All fields are zero.  */
>  extern const struct frame_id null_frame_id;
> @@ -120,9 +136,20 @@
>  /* Construct a frame ID.  The first parameter is the frame's constant
>     stack address (typically the outer-bound), and the second the
>     frame's constant code address (typically the entry point) (or zero,
> -   to indicate a wild card).  */
> +   to indicate a wild card).  The special identifier address is
> +   defaulted to zero.  */
>  extern struct frame_id frame_id_build (CORE_ADDR stack_addr,
>  				       CORE_ADDR code_addr);
> +
> +/* Construct a special frame ID.  The first parameter is the frame's constant
> +   stack address (typically the outer-bound), the second is the
> +   frame's constant code address (typically the entry point) (or zero,
> +   to indicate a wild card), and the third parameter is the frame's
> +   special identifier address (or zero to indicate a wild card or 
> +   unused default).  */
> +extern struct frame_id frame_id_build_special (CORE_ADDR stack_addr,
> +					       CORE_ADDR code_addr,
> +					       CORE_ADDR special_addr);
>  
>  /* Returns non-zero when L is a valid frame (a valid frame has a
>     non-zero .base).  */
> Index: frame.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/frame.c,v
> retrieving revision 1.145
> diff -u -r1.145 frame.c
> --- frame.c	2 Oct 2003 20:28:29 -0000	1.145
> +++ frame.c	16 Oct 2003 23:30:51 -0000
> @@ -144,9 +144,10 @@
>  void
>  fprint_frame_id (struct ui_file *file, struct frame_id id)
>  {
> -  fprintf_unfiltered (file, "{stack=0x%s,code=0x%s}",
> +  fprintf_unfiltered (file, "{stack=0x%s,code=0x%s,special=0x%s}",
>  		      paddr_nz (id.stack_addr),
> -		      paddr_nz (id.code_addr));
> +		      paddr_nz (id.code_addr),
> +		      paddr_nz (id.special_addr));
>  }
>  
>  static void
> @@ -256,14 +257,22 @@
>  const struct frame_id null_frame_id; /* All zeros.  */
>  
>  struct frame_id
> -frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr)
> +frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr,
> +                        CORE_ADDR special_addr)
>  {
>    struct frame_id id;
>    id.stack_addr = stack_addr;
>    id.code_addr = code_addr;
> +  id.special_addr = special_addr;
>    return id;
>  }
>  
> +struct frame_id
> +frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr)
> +{
> +  return frame_id_build_special (stack_addr, code_addr, 0);
> +}
> +
>  int
>  frame_id_p (struct frame_id l)
>  {
> @@ -292,8 +301,14 @@
>    else if (l.code_addr == 0 || r.code_addr == 0)
>      /* A zero code addr is a wild card, always succeed.  */
>      eq = 1;
> -  else if (l.code_addr == r.code_addr)
> -    /* The .stack and .code are identical, the ID's are identical.  */
> +  else if (l.code_addr != r.code_addr)
> +    /* If .code addresses are different, the frames are different.  */
> +    eq = 0;
> +  else if (l.special_addr == 0 || r.special_addr == 0)
> +    /* A zero special addr is a wild card (or unused), always succeed.  */
> +    eq = 1;
> +  else if (l.special_addr == r.special_addr)
> +    /* Frames are equal.  */
>      eq = 1;
>    else
>      /* No luck.  */
> @@ -320,7 +335,7 @@
>      /* Only return non-zero when strictly inner than.  Note that, per
>         comment in "frame.h", there is some fuzz here.  Frameless
>         functions are not strictly inner than (same .stack but
> -       different .code).  */
> +       different .code and/or .special address).  */
>      inner = INNER_THAN (l.stack_addr, r.stack_addr);
>    if (frame_debug)
>      {