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| author | Jonathan Wakely <jwakely@redhat.com> | 2022-01-17 23:53:37 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2022-01-18 09:51:02 +0000 |
| commit | 5f3c0ee908b5e10f5226be0bad8b4ac55d41d985 (patch) | |
| tree | 117d5c610624840b395bda0c5fbfd07cdcfbb2e5 | |
| parent | e8feb059ca2b3fb50a1ccec01a49f119ec223084 (diff) | |
| download | gcc-5f3c0ee908b5e10f5226be0bad8b4ac55d41d985.zip gcc-5f3c0ee908b5e10f5226be0bad8b4ac55d41d985.tar.gz gcc-5f3c0ee908b5e10f5226be0bad8b4ac55d41d985.tar.bz2 | |
libstdc++: Improve comments describing --enable-fully-dynamic-string
libstdc++-v3/ChangeLog:
* acinclude.m4 (GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING): Improve
comments.
* configure: Regenerate.
| -rw-r--r-- | libstdc++-v3/acinclude.m4 | 17 | ||||
| -rwxr-xr-x | libstdc++-v3/configure | 4 |
2 files changed, 13 insertions, 8 deletions
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 336c690..930861e 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -499,19 +499,24 @@ AC_DEFUN([GLIBCXX_CHECK_LFS], [ dnl -dnl Check for whether a fully dynamic basic_string implementation should -dnl be turned on, that does not put empty objects in per-process static -dnl memory (mostly useful together with shared memory allocators, see PR -dnl libstdc++/16612 for details). +dnl Check whether the old Copy-On-Write basic_string should allocate a new +dnl empty representation for every default-constructed basic_string. Without +dnl this option, COW strings share a single empty rep in static storage, +dnl but this only works if the linker can guarantee the static storage has +dnl a unique definition in the process. It also doesn't work if basic_string +dnl objects are stored in shared memory (see PR libstdc++/16612). +dnl When fully dynamic strings are enabled, the static storage is not used +dnl and a new empty string with reference-count == 1 is allocated each time. +dnl Enabling this changes the libstdc++.so ABI. dnl dnl --enable-fully-dynamic-string defines _GLIBCXX_FULLY_DYNAMIC_STRING to 1 dnl --disable-fully-dynamic-string defines _GLIBCXX_FULLY_DYNAMIC_STRING to 0 -dnl otherwise undefined +dnl otherwise the macro is not defined. dnl + Usage: GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING[(DEFAULT)] dnl Where DEFAULT is either `yes' or `no'. dnl AC_DEFUN([GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING], [ - GLIBCXX_ENABLE(fully-dynamic-string,$1,,[do not put empty strings in per-process static memory]) + GLIBCXX_ENABLE(fully-dynamic-string,$1,,[do not put empty strings in per-process static memory], [permit yes|no]) if test $enable_fully_dynamic_string = yes; then enable_fully_dynamic_string_def=1 else diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure index 34f6718..4c9be00 100755 --- a/libstdc++-v3/configure +++ b/libstdc++-v3/configure @@ -18679,8 +18679,8 @@ if test "${enable_fully_dynamic_string+set}" = set; then : enableval=$enable_fully_dynamic_string; case "$enableval" in yes|no) ;; - *) as_fn_error $? "Argument to enable/disable fully-dynamic-string must be yes or no" "$LINENO" 5 ;; - esac + *) as_fn_error $? "Unknown argument to enable/disable fully-dynamic-string" "$LINENO" 5 ;; + esac else enable_fully_dynamic_string=no |