From: John David Anglin <danglin@gcc.gnu.org>
Date: Mon, 27 Jan 2025 17:39:00 +0000 (-0500)
Subject: c++: Use mapped reads and writes when munmap and msync are available
X-Git-Tag: basepoints/gcc-16~2320
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9d450dee7112635a541c5a34268d54f63da48f71;p=thirdparty%2Fgcc.git

c++: Use mapped reads and writes when munmap and msync are available

Module support is broken when MAPPED_READING and MAPPED_WRITING
are defined to 0.  This causes internal compiler errors in the
permissive-error-1.C and permissive-error-2.C tests.

HP-UX 11.11 doesn't define _POSIX_MAPPED_FILES but it does have
munmap and msync.  Testing indicates support is sufficient for
c++ modules, so use checks for these functions instead of
_POSIX_MAPPED_FILES check.

2025-01-27  John David Anglin  <danglin@gcc.gnu.org>

gcc/ChangeLog:

	PR c++/116524
	* configure.ac: Check for munmap and msync.
	* configure: Regenerate.
	* config.in: Regenerate.

gcc/cp/ChangeLog:
	* module.cc: Test HAVE_MUNMAP and HAVE_MSYNC instead of
	_POSIX_MAPPED_FILES > 0.
---

diff --git a/gcc/config.in b/gcc/config.in
index 44de5a54611..3b06533c482 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -1972,6 +1972,18 @@
 #endif
 
 
+/* Define to 1 if you have the `msync' function. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_MSYNC
+#endif
+
+
+/* Define to 1 if you have the `munmap' function. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_MUNMAP
+#endif
+
+
 /* Define if GCC has been configured with --enable-newlib-nano-formatted-io.
    */
 #ifndef USED_FOR_TARGET
diff --git a/gcc/configure b/gcc/configure
index b4c52de6218..e36d1d91612 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -10637,7 +10637,7 @@ for ac_func in times clock kill getrlimit setrlimit atoq \
 	popen sysconf strsignal getrusage nl_langinfo \
 	gettimeofday mbstowcs wcswidth mmap posix_fallocate setlocale \
 	clearerr_unlocked feof_unlocked   ferror_unlocked fflush_unlocked fgetc_unlocked fgets_unlocked   fileno_unlocked fprintf_unlocked fputc_unlocked fputs_unlocked   fread_unlocked fwrite_unlocked getchar_unlocked getc_unlocked   putchar_unlocked putc_unlocked madvise mallinfo mallinfo2 fstatat getauxval \
-	clock_gettime
+	clock_gettime munmap msync
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_cxx_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 6c38c4925fb..8fab93c9365 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -1574,7 +1574,7 @@ AC_CHECK_FUNCS(times clock kill getrlimit setrlimit atoq \
 	popen sysconf strsignal getrusage nl_langinfo \
 	gettimeofday mbstowcs wcswidth mmap posix_fallocate setlocale \
 	gcc_UNLOCKED_FUNCS madvise mallinfo mallinfo2 fstatat getauxval \
-	clock_gettime)
+	clock_gettime munmap msync)
 
 # At least for glibc, clock_gettime is in librt.  But don't pull that
 # in if it still doesn't give us the function we want.
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 312ff668750..59716e1873e 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -241,11 +241,11 @@ Classes used:
 #define MAPPED_READING 0
 #define MAPPED_WRITING 0
 #else
-#if HAVE_MMAP_FILE && _POSIX_MAPPED_FILES > 0
-/* mmap, munmap.  */
+#if HAVE_MMAP_FILE && HAVE_MUNMAP && HAVE_MSYNC
+/* mmap, munmap, msync.  */
 #define MAPPED_READING 1
 #if HAVE_SYSCONF && defined (_SC_PAGE_SIZE)
-/* msync, sysconf (_SC_PAGE_SIZE), ftruncate  */
+/* sysconf (_SC_PAGE_SIZE), ftruncate  */
 /* posix_fallocate used if available.  */
 #define MAPPED_WRITING 1
 #else