From c644b7df11afc818d6308c3776813e50e4ebe551 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Wed, 13 Apr 2022 14:09:33 +0100 Subject: [PATCH] libstdc++: Use LTLIBICONV when linking libstdc++.so [PR93602] This fixes missing libiconv symbols when libstdc++ is built on a system that has libiconv installed. If the libiconv headers are found then libstdc++ depends on libiconv_open etc instead of libc's iconv_open. But without this fix libstdc++ is not linked to the libiconv library that provides the definitions of those symbols. As discussed in PR 93602 this changed means that libstdc++.so.6 might have an rpath pointing to the location of the libiconv.so library. If that is not desired, then GCC must be configured to link to a static libiconv.a instead, using either --with-libiconv-type=static or an in-tree build of libiconv. libstdc++-v3/ChangeLog: PR libstdc++/93602 * doc/xml/manual/prerequisites.xml: Document libiconv workarounds. * doc/html/manual/setup.html: Regenerate. * src/Makefile.am (CXXLINK): Add $(LTLIBICONV). * src/Makefile.in: Regenerate. --- libstdc++-v3/doc/html/manual/setup.html | 33 ++++++++++++++++++ libstdc++-v3/doc/xml/manual/prerequisites.xml | 50 +++++++++++++++++++++++++++ libstdc++-v3/src/Makefile.am | 4 ++- libstdc++-v3/src/Makefile.in | 4 ++- 4 files changed, 89 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/doc/html/manual/setup.html b/libstdc++-v3/doc/html/manual/setup.html index 636a440..069354b 100644 --- a/libstdc++-v3/doc/html/manual/setup.html +++ b/libstdc++-v3/doc/html/manual/setup.html @@ -42,6 +42,39 @@

Finally, a few system-specific requirements:

linux

+ The 'gnu' locale model makes use of iconv + for character set conversions. The relevant functions are provided + by Glibc and so are always available, however they can also be + provided by the separate GNU libiconv library. If GNU libiconv is + found when GCC is built (e.g., because its headers are installed + in /usr/local/include) + then the libstdc++.so.6 library will have a + run-time dependency on libiconv.so.2. + If you do not want that run-time dependency then you should do + one of the following: +

  • + Uninstall the libiconv headers before building GCC. + Glibc already provides iconv so you should + not need libiconv anyway. +

  • + + Download the libiconv sources and extract them into the + top level of the GCC source tree, e.g., + 

    +wget https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.16.tar.gz
+tar xf libiconv-1.16.tar.gz
+ln -s libiconv-1.16 libiconv
+

    + This will build libiconv as part of building GCC and link to + it statically, so there is no libiconv.so.2 + dependency. +

  • + Configure GCC with --with-libiconv-type=static. + This requires the static libiconv.a library, + which is not installed by default. You might need to reinstall + libiconv using the --enable-static configure + option to get the static library. +

If GCC 3.1.0 or later on is being used on GNU/Linux, an attempt will be made to use "C" library functionality necessary for C++ named locale support. For GCC 4.6.0 and later, this diff --git a/libstdc++-v3/doc/xml/manual/prerequisites.xml b/libstdc++-v3/doc/xml/manual/prerequisites.xml index 22e90a7..8799487 100644 --- a/libstdc++-v3/doc/xml/manual/prerequisites.xml +++ b/libstdc++-v3/doc/xml/manual/prerequisites.xml @@ -50,6 +50,56 @@ + The 'gnu' locale model makes use of iconv + for character set conversions. The relevant functions are provided + by Glibc and so are always available, however they can also be + provided by the separate GNU libiconv library. If GNU libiconv is + found when GCC is built (e.g., because its headers are installed + in /usr/local/include) + then the libstdc++.so.6 library will have a + run-time dependency on libiconv.so.2. + If you do not want that run-time dependency then you should do + one of the following: + + + + + Uninstall the libiconv headers before building GCC. + Glibc already provides iconv so you should + not need libiconv anyway. + + + + + + Download the libiconv sources and extract them into the + top level of the GCC source tree, e.g., + + +wget https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.16.tar.gz +tar xf libiconv-1.16.tar.gz +ln -s libiconv-1.16 libiconv + + + This will build libiconv as part of building GCC and link to + it statically, so there is no libiconv.so.2 + dependency. + + + + + Configure GCC with . + This requires the static libiconv.a library, + which is not installed by default. You might need to reinstall + libiconv using the configure + option to get the static library. + + + + + + + If GCC 3.1.0 or later on is being used on GNU/Linux, an attempt will be made to use "C" library functionality necessary for C++ named locale support. For GCC 4.6.0 and later, this diff --git a/libstdc++-v3/src/Makefile.am b/libstdc++-v3/src/Makefile.am index 18f5763..9c3f4ac 100644 --- a/libstdc++-v3/src/Makefile.am +++ b/libstdc++-v3/src/Makefile.am @@ -278,7 +278,9 @@ CXXLINK = \ $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) \ --mode=link $(CXX) \ $(VTV_CXXLINKFLAGS) \ - $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) $(LTLDFLAGS) -o $@ + $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) \ + $(LTLDFLAGS) $(LTLIBICONV) \ + -o $@ # Symbol versioning for shared libraries. if ENABLE_SYMVERS diff --git a/libstdc++-v3/src/Makefile.in b/libstdc++-v3/src/Makefile.in index eeafb89..4a06f6c 100644 --- a/libstdc++-v3/src/Makefile.in +++ b/libstdc++-v3/src/Makefile.in @@ -643,7 +643,9 @@ CXXLINK = \ $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) \ --mode=link $(CXX) \ $(VTV_CXXLINKFLAGS) \ - $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) $(LTLDFLAGS) -o $@ + $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) \ + $(LTLDFLAGS) $(LTLIBICONV) \ + -o $@ @ENABLE_SYMVERS_TRUE@CLEANFILES = libstdc++-symbols.ver $(version_dep) @ENABLE_SYMVERS_DARWIN_TRUE@@ENABLE_SYMVERS_TRUE@version_arg = -Wl,-exported_symbols_list,libstdc++-symbols.explist -- 2.7.4