Jakub Jelinek <ja...@redhat.com> writes:
> Hi!
>
> The recent pp_wide_int changes for _BitInt support (because not all
> wide_ints fit into the small fixed size digit_buffer anymore) apparently
> broke
> +FAIL: gcc.dg/analyzer/out-of-bounds-diagram-1-debug.c (test for excess
> errors)
> +FAIL: gcc.dg/analyzer/out-of-bounds-diagram-1-debug.c 2 blank line(s) in
> output
> +FAIL: gcc.dg/analyzer/out-of-bounds-diagram-1-debug.c expected multiline
> pattern lines 17-39
> (and I couldn't reproduce that in bisect seed (which is -O0 compiled) and
> thought it would be some analyzer diagnostic bug).
>
> The problem is that analyzer uses pp_wide_int with a function call in the
> second argument. Previously, when pp_wide_int macro just did
> print_dec (W, pp_buffer (PP)->digit_buffer, SGN);
> pp_string (PP, pp_buffer (PP)->digit_buffer);
> it worked, because the const wide_int_ref & first argument to print_dec
> bound to a temporary, which was only destructed at the end of the full
> statement after print_dec was called.
> But with my changes where I need to first compare the precision of the
> const wide_int_ref & to decide whether to use digit_buffer or XALLOCAVEC
> something larger, this means that pp_wide_int_ref binds to a temporary
> which is destroyed at the end of full statement which is the
> const wide_int_ref &pp_wide_int_ref = (W);
> declaration, so then invokes UB accessing a destructed temporary.
>
> The following patch fixes it by rewriting pp_wide_int into an inline
> function, so that the end of the full statement is the end of the inline
> function call. As functions using alloca aren't normally inlined, I've
> also split that part into a separate out of line function. Putting that
> into pretty-print.cc didn't work, e.g. the gm2 binary doesn't link,
> because pretty-print.o is in libcommon.a, but wide-print-print.o which
> defines print_dec is not. So I've put that out of line function into
> wide-int-print.cc instead.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2023-09-08 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/111329
> * pretty-print.h (pp_wide_int): Rewrite from macro into inline
> function. For printing values which don't fit into digit_buffer
> use out-of-line function.
> * wide-int-print.h (pp_wide_int_large): Declare.
> * wide-int-print.cc: Include pretty-print.h.
> (pp_wide_int_large): Define.
OK, thanks.
Richard
> --- gcc/pretty-print.h.jj 2023-09-06 14:36:53.485246347 +0200
> +++ gcc/pretty-print.h 2023-09-08 11:11:21.173649942 +0200
> @@ -333,28 +333,6 @@ pp_get_prefix (const pretty_printer *pp)
> #define pp_decimal_int(PP, I) pp_scalar (PP, "%d", I)
> #define pp_unsigned_wide_integer(PP, I) \
> pp_scalar (PP, HOST_WIDE_INT_PRINT_UNSIGNED, (unsigned HOST_WIDE_INT) I)
> -#define pp_wide_int(PP, W, SGN) \
> - do \
> - { \
> - const wide_int_ref &pp_wide_int_ref = (W); \
> - unsigned int pp_wide_int_prec \
> - = pp_wide_int_ref.get_precision (); \
> - if ((pp_wide_int_prec + 3) / 4 \
> - > sizeof (pp_buffer (PP)->digit_buffer) - 3) \
> - { \
> - char *pp_wide_int_buf \
> - = XALLOCAVEC (char, (pp_wide_int_prec + 3) / 4 + 3);\
> - print_dec (pp_wide_int_ref, pp_wide_int_buf, SGN); \
> - pp_string (PP, pp_wide_int_buf); \
> - } \
> - else \
> - { \
> - print_dec (pp_wide_int_ref, \
> - pp_buffer (PP)->digit_buffer, SGN); \
> - pp_string (PP, pp_buffer (PP)->digit_buffer); \
> - } \
> - } \
> - while (0)
> #define pp_vrange(PP, R) \
> do \
> { \
> @@ -453,6 +431,19 @@ pp_wide_integer (pretty_printer *pp, HOS
> pp_scalar (pp, HOST_WIDE_INT_PRINT_DEC, i);
> }
>
> +inline void
> +pp_wide_int (pretty_printer *pp, const wide_int_ref &w, signop sgn)
> +{
> + unsigned int prec = w.get_precision ();
> + if (UNLIKELY ((prec + 3) / 4 > sizeof (pp_buffer (pp)->digit_buffer) - 3))
> + pp_wide_int_large (pp, w, sgn);
> + else
> + {
> + print_dec (w, pp_buffer (pp)->digit_buffer, sgn);
> + pp_string (pp, pp_buffer (pp)->digit_buffer);
> + }
> +}
> +
> template<unsigned int N, typename T>
> void pp_wide_integer (pretty_printer *pp, const poly_int_pod<N, T> &);
>
> --- gcc/wide-int-print.h.jj 2023-09-08 11:03:48.320944156 +0200
> +++ gcc/wide-int-print.h 2023-09-08 11:11:46.982292282 +0200
> @@ -34,5 +34,6 @@ extern void print_decu (const wide_int_r
> extern void print_decu (const wide_int_ref &wi, FILE *file);
> extern void print_hex (const wide_int_ref &wi, char *buf);
> extern void print_hex (const wide_int_ref &wi, FILE *file);
> +extern void pp_wide_int_large (pretty_printer *, const wide_int_ref &,
> signop);
>
> #endif /* WIDE_INT_PRINT_H */
> --- gcc/wide-int-print.cc.jj 2023-09-08 11:03:51.543898946 +0200
> +++ gcc/wide-int-print.cc 2023-09-08 11:12:11.481952762 +0200
> @@ -21,6 +21,7 @@ along with GCC; see the file COPYING3.
> #include "config.h"
> #include "system.h"
> #include "coretypes.h"
> +#include "pretty-print.h"
>
> /*
> * public printing routines.
> @@ -138,3 +139,14 @@ print_hex (const wide_int_ref &wi, FILE
> fputs (buf, file);
> }
>
> +/* Print larger precision wide_int. Not defined as inline in a header
> + together with pp_wide_int because XALLOCAVEC will make it uninlinable. */
> +
> +void
> +pp_wide_int_large (pretty_printer *pp, const wide_int_ref &w, signop sgn)
> +{
> + unsigned int prec = w.get_precision ();
> + char *buf = XALLOCAVEC (char, (prec + 3) / 4 + 3);
> + print_dec (w, buf, sgn);
> + pp_string (pp, buf);
> +}
>
> Jakub
