From 0f50c8e32c872097f86c424a17e2e4f856bd2f6e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Date: Fri, 17 May 2019 23:58:47 +0200 Subject: [PATCH] Makefile: remove the NO_R_TO_GCC_LINKER flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Change our default CC_LD_DYNPATH invocation to something GCC likes these days. Since the GCC 4.6 release unknown flags haven't been passed through to ld(1). Thus our previous default of CC_LD_DYNPATH=-R would cause an error on modern GCC unless NO_R_TO_GCC_LINKER was set. This CC_LD_DYNPATH flag is really obscure, and I don't expect anyone except those working on git development ever use this. It's not needed to simply link to libraries like say libpcre, but *only* for those cases where we're linking to such a library not present in the OS's library directories. See e.g. ldconfig(8) on Linux for more details. I use this to compile my git with a LIBPCREDIR=$HOME/g/pcre2/inst as I'm building that from source, but someone maintaining an OS package is almost certainly not going to use this. They're just going to set USE_LIBPCRE=YesPlease after installing the libpcre dependency, which'll point to OS libraries which ld(1) will find without the help of CC_LD_DYNPATH. Another thing that helps mitigate any potential breakage is that we detect the right type of invocation in configure.ac, which e.g. HP/UX uses[1], as does IBM's AIX package[2]. From what I can tell both AIX and Solaris packagers are building git with GCC, so I'm not adding a corresponding config.mak.uname default to cater to their OS-native linkers. Now for an overview of past development in this area: Our use of "-R" dates back to 455a7f3275 ("More portability.", 2005-09-30). Soon after that in bbfc63dd78 ("gcc does not necessarily pass runtime libpath with -R", 2006-12-27) the NO_R_TO_GCC flag was added, allowing optional use of "-Wl,-rpath=". Then in f5b904db6b ("Makefile: Allow CC_LD_DYNPATH to be overriden", 2008-08-16) the ability to override this flag to something else entirely was added, as some linkers use neither "-Wl,-rpath," nor "-R". From what I can tell we should, with the benefit of hindsight, have made this change back in 2006. GCC & ld supported this type of invocation back then, or since at least binutils-gdb.git's[3] a1ad915dc4 ("[...]Add support for -rpath[...]", 1994-07-20). Further reading and prior art can be found at [4][5][6][7]. Making a plain "-R" an error seems from reading those reports to have been introduced in GCC 4.6 released on March 25, 2011[8], but I couldn't confirm this with absolute certainty, its release notes are ambiguous on the subject, and I couldn't be bothered to try to build & bisect it against GCC 4.5. 1. https://public-inbox.org/git/20190516093412.14795-1-avarab@gmail.com/ 2. https://www.ibm.com/developerworks/aix/library/aix-toolbox/alpha.html 3. git://sourceware.org/git/binutils-gdb.git 4. https://github.com/tsuna/boost.m4/issues/15 5. https://bugzilla.gnome.org/show_bug.cgi?id=641416 6. https://stackoverflow.com/questions/12629042/g-4-6-real-error-unrecognized-option-r 7. https://curl.haxx.se/mail/archive-2014-11/0005.html 8. https://gcc.gnu.org/gcc-4.6/changes.html Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano --- Makefile | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) diff --git a/Makefile b/Makefile index f965509b3c..ce7a489d64 100644 --- a/Makefile +++ b/Makefile @@ -265,10 +265,6 @@ all:: # # Define NO_DEFLATE_BOUND if your zlib does not have deflateBound. # -# Define NO_R_TO_GCC_LINKER if your gcc does not like "-R/path/lib" -# that tells runtime paths to dynamic libraries; -# "-Wl,-rpath=/path/lib" is used instead. -# # Define NO_NORETURN if using buggy versions of gcc 4.6+ and profile feedback, # as the compiler can crash (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49299) # @@ -1160,6 +1156,7 @@ endif # which'll override these defaults. CFLAGS = -g -O2 -Wall LDFLAGS = +CC_LD_DYNPATH = -Wl,-rpath, BASIC_CFLAGS = -I. BASIC_LDFLAGS = @@ -1287,16 +1284,6 @@ ifeq ($(uname_S),Darwin) PTHREAD_LIBS = endif -ifndef CC_LD_DYNPATH - ifdef NO_R_TO_GCC_LINKER - # Some gcc does not accept and pass -R to the linker to specify - # the runtime dynamic library path. - CC_LD_DYNPATH = -Wl,-rpath, - else - CC_LD_DYNPATH = -R - endif -endif - ifdef NO_LIBGEN_H COMPAT_CFLAGS += -DNO_LIBGEN_H COMPAT_OBJS += compat/basename.o