From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
Subject: gcc/11 libestdc++: drop sprintf ld warnings
To: ports@openbsd.org
Cc: Pascal Stumpf <pascal@stumpf.co>
Date: Sun, 14 Sep 2025 17:51:17 +0200


ld.bfd spots it with a "hello, world!" program, ld.lld doesn't.  The
sprintf_ld() change is adapted from code already in lang/gcc/15.
Since that function is internal, it's not a problem.

With this, eg++ (-fuse-ld=bfd) doesn't warn about the sprintf use.
This matters for some overly picky ports that fail to find a working
C++ compiler when ld(1) spits any warning.  Diff for gcc/15 to follow.

ok?


Index: Makefile
===================================================================
RCS file: /home/cvs/ports/lang/gcc/11/Makefile,v
diff -u -p -r1.52 Makefile
--- Makefile	13 Sep 2025 14:45:15 -0000	1.52
+++ Makefile	14 Sep 2025 15:41:14 -0000
@@ -17,7 +17,7 @@ USE_NOEXECONLY = Yes
 V = 11.2.0
 FULL_VERSION = $V
 FULL_PKGVERSION = $V
-REVISION = 18
+REVISION = 19
 
 ADASTRAP-amd64 = adastrap-amd64-$V-5.tar.xz
 ADASTRAP-i386 = adastrap-i386-$V-4.tar.xz
Index: patches/patch-libstdc++-v3_src_c++17_floating_to_chars_cc
===================================================================
RCS file: patches/patch-libstdc++-v3_src_c++17_floating_to_chars_cc
diff -N patches/patch-libstdc++-v3_src_c++17_floating_to_chars_cc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ patches/patch-libstdc++-v3_src_c++17_floating_to_chars_cc	13 Sep 2025 18:02:43 -0000
@@ -0,0 +1,44 @@
+Avoid using sprintf, aside from its unsafety it triggers ld(1)
+warnings leading to broken feature detection when linking test
+programs with libestdc++.
+
+Index: libstdc++-v3/src/c++17/floating_to_chars.cc
+--- libstdc++-v3/src/c++17/floating_to_chars.cc.orig
++++ libstdc++-v3/src/c++17/floating_to_chars.cc
+@@ -879,7 +879,8 @@ namespace
+ #pragma GCC diagnostic ignored "-Wabi"
+   template<typename T, typename... Extra>
+   inline int
+-  sprintf_ld(char* buffer, const char* format_string, T value, Extra... args)
++  sprintf_ld(char* buffer, size_t length __attribute__((unused)),
++             const char* format_string, T value, Extra... args)
+   {
+     int len;
+ 
+@@ -894,7 +895,7 @@ namespace
+       len = __sprintfieee128(buffer, format_string, args..., value);
+     else
+ #endif
+-    len = sprintf(buffer, format_string, args..., value);
++    len = snprintf(buffer, length, format_string, args..., value);
+ 
+ #if _GLIBCXX_USE_C99_FENV_TR1 && defined(FE_TONEAREST)
+     if (saved_rounding_mode != FE_TONEAREST)
+@@ -1040,7 +1041,7 @@ template<typename T>
+ 	    // digit, and carefully compute and write the last digit
+ 	    // ourselves.
+ 	    char buffer[expected_output_length+1];
+-	    const int output_length = sprintf_ld(buffer, "%.0Lf", value);
++	    const int output_length = sprintf_ld(buffer, sizeof(buffer), "%.0Lf", value);
+ 	    __glibcxx_assert(output_length == expected_output_length);
+ 	    memcpy(first, buffer, output_length);
+ 	    return {first + output_length, errc{}};
+@@ -1227,7 +1228,7 @@ template<typename T>
+ 	// Do the sprintf into the local buffer.
+ 	char buffer[output_length_upper_bound+1];
+ 	int output_length
+-	  = sprintf_ld(buffer, output_specifier, value, effective_precision);
++	  = sprintf_ld(buffer, sizeof(buffer), output_specifier, value, effective_precision);
+ 	__glibcxx_assert(output_length <= output_length_upper_bound);
+ 
+ 	if (effective_precision > 0)

-- 
jca