Re: [patch/rfa] fix call-dummies for hppa

[Andrew Cagney <cagney@gnu.org>]

> This fixes a few bugs in the 32-bit version of the hppa push_dummy_call
> method.
> 
> Tested against hppa2.0w-hp-hpux11.11 and hppa-linux.

Which compilers?  I'm suspicious of GCC - it too often gets struct 
parameters and return values internally consistent but wrong :-(

> All of structs.exp pass, there are still some failures in call-sc.exp
> and callfuncs.exp. In the latter case it appears most are due to
> problems with calling malloc() in the inferior (at least on hppa-linux).

>     We simply allocate the appropriate amount of stack space and put
>     arguments into their proper slots.  */
> -   
> +

Be careful of white space change, this shouldn't be included.  If you 
want to fix some indention just do it separatly.

>  CORE_ADDR
>  hppa32_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr,
>  			struct regcache *regcache, CORE_ADDR bp_addr,
>  			int nargs, struct value **args, CORE_ADDR sp,
>  			int struct_return, CORE_ADDR struct_addr)
>  {
> -  /* NOTE: cagney/2004-02-27: This is a guess - its implemented by
> -     reverse engineering testsuite failures.  */
> -

(I've now got a copy of the 32-bit ABI but it doesn't help much)

>    /* Stack base address at which any pass-by-reference parameters are
>       stored.  */
>    CORE_ADDR struct_end = 0;
> @@ -781,12 +779,15 @@ hppa32_push_dummy_call (struct gdbarch *
>    /* Two passes.  First pass computes the location of everything,
>       second pass writes the bytes out.  */
>    int write_pass;
> +
>    for (write_pass = 0; write_pass < 2; write_pass++)
>      {
>        CORE_ADDR struct_ptr = 0;
> -      CORE_ADDR param_ptr = 0;
> -      int reg = 27;	      /* NOTE: Registers go down.  */

the comment doesn't match the assignment.

> +      /* The first parameter goes into sp-36, each stack slot is 4-bytes.  */
> +      CORE_ADDR param_ptr = 32;
>        int i;
> +      int small_struct = 0;
> +
>        for (i = 0; i < nargs; i++)
>  	{
>  	  struct value *arg = args[i];
> @@ -795,6 +796,7 @@ hppa32_push_dummy_call (struct gdbarch *
>  	     stack, and [possibly] passed in a register.  */
>  	  char param_val[8];
>  	  int param_len;
> +
>  	  memset (param_val, 0, sizeof param_val);
>  	  if (TYPE_LENGTH (type) > 8)
>  	    {
> @@ -813,27 +815,76 @@ hppa32_push_dummy_call (struct gdbarch *
>  	      /* Integer value store, right aligned.  "unpack_long"
>  		 takes care of any sign-extension problems.  */
>  	      param_len = align_up (TYPE_LENGTH (type), 4);
> +
white space
>  	      store_unsigned_integer (param_val, param_len,
>  				      unpack_long (type,
>  						   VALUE_CONTENTS (arg)));
>  	    }
> +	  else if (TYPE_CODE (type) == TYPE_CODE_FLT)
> +            {

more comments (the rest is well commented), ``&& TYPE_LENGTH () == 4'' 
test needed?

> +	      param_len = align_up (TYPE_LENGTH (type), 4);
> +	      memcpy (param_val, VALUE_CONTENTS (arg), param_len);
> +            }
>  	  else
>  	    {
> -	      /* Small struct value, store right aligned?  */
>  	      param_len = align_up (TYPE_LENGTH (type), 4);
> +
> +	      /* Small struct value are stored right-aligned.  */
>  	      memcpy (param_val + param_len - TYPE_LENGTH (type),
>  		      VALUE_CONTENTS (arg), TYPE_LENGTH (type));
> +
> +	      /* Structures of size 5, 6 and 7 bytes are special in that
> +	         the higher-ordered word is stored in the lower-ordered
> +		 argument, and even though it is a 8-byte quantity the
> +		 registers need not be 8-byte aligned.  */
> +	      if (param_len > 4)
> +		small_struct = 1;
>  	    }
> +
>  	  param_ptr += param_len;
> -	  reg -= param_len / 4;
> +	  if (param_len == 8 && !small_struct)
> +	    param_ptr += (param_ptr & 4);

align_up?

Otherwize, yep, thanks for fixing this.

Andrew