Re: How to GTYize a struct properly?

[Daniel Berlin <dberlin at dberlin dot org>]

Laurynas Biveinis wrote:
> Hi,
> 
> For typed GC allocation I've to add GTY markers for a few datatypes.
> An example from value-prof.h:
> 
> Before:
> 
> struct histogram_value_t
> {
>   struct
>     {                   /* <--- line 48, error below occurs here */
>       tree value;		/* The value to profile.  */
>       tree stmt;		/* Insn containing the value.  */
>       gcov_type *counters;		        /* Pointer to first counter.  */
>       struct histogram_value_t *next;		/* Linked list pointer.  */
>     } hvalue;
>   enum hist_type type;			/* Type of information to measure.  */
>   unsigned n_counters;			/* Number of required counters.  */
>   union
>     {
>       struct
> 	{
> 	  int int_start;	/* First value in interval.  */
> 	  unsigned int steps;	/* Number of values in it.  */
> 	} intvl;	/* Interval histogram data.  */
>     } hdata;		/* Profiled information specific data.  */
> };
> 
> 
> After my best effor so far:
> 
> struct histogram_value_t GTY(())
> {
>   struct
>     {                        /* <--- line 48, error below occurs here */
>       tree value;		/* The value to profile.  */
>       tree stmt;		/* Insn containing the value.  */
>       gcov_type *counters;		        /* Pointer to first counter.  */
>       struct histogram_value_t GTY((chain_next("%h.next")) *next;		/*
> Linked list pointer.  */
>     } hvalue;
>   enum hist_type type;			/* Type of information to measure.  */
>   unsigned n_counters;			/* Number of required counters.  */
>   union
>     {
>       struct
> 	{
> 	  int int_start;	/* First value in interval.  */
> 	  unsigned int steps;	/* Number of values in it.  */
> 	} intvl;	/* Interval histogram data.  */
>     } GTY ((default("intvl")) hdata;		/* Profiled information specific data.  */
> };
> 
> And this one gives a gengtype error:
> 
> ../../gcc-boehm-custom-marking/gcc/value-prof.h:48: syntax error,
> unexpected '*', expecting ')'
> 
> What should I do about it?
> 

Have to typedef the pointer due to gengtype silliness, IIRC.

IE typedef struct histogram_value_t *histogram_value_t_p;

then use histogram_value_t_p in the structure with the gty marker.