[PATCH 0/4] Darwin: Replace environment runpath with embedded [PR88590].

[PATCH 0/4] Darwin: Replace environment runpath with embedded [PR88590].

[Iain Sandoe]

This is a fairly long explanation of the problems being addressed by
the patch set.  Most of the changes are Darwin-specific - a change to
the libtool component allowing for this @rpath and some minor additions
to makefiles where libtool is not in use.  At present, this seems pretty
specific to the GCC build; since we depend on accessing newly-built
components during the bootstrap.

There are additional details relevant to each patch in its own commit
message.

=====

Darwin builds shared libraries with information on the runpath as part
of the library name.  For example, /installation/path/for/libfoo.dylib.

That is regarded as two components; the 'runpath' /installation/path/for/
and the library name libfoo.dylib.

This means that (at runtime) two libraries with the same name can be
disambiguated by their runpaths, and potentially used by the same exe.

===== Problem #1

That is fine and works well; until we disturb the assumptions by
overriding the library runpath with an environment one: DYLD_LIBRARY_PATH.

Now the library runpath(s) can be discarded and the libraries are first
searched on the basis of that provided by the environment; two libraries
with the same name are no longer distinct (if a library with that name is
found in the environment path).

This causes problems in configuring, building and testing GCC because we
set the runpath environment at a very high level so that it applies to
stage1+ target configures and stage2+ host configures.  This is needed so
that executables built during those configures get the newly-built libgcc_s
when the target defaults to using a shared libgcc.

However, it also means that every tool that is used during the configure
has its libgcc_s (or any of the newly-built bootstrapped libs) overriden
to use the new one(s) - which might be buggy.

In the testsuite it is more serious - since more target libs come into
play - especially libstdc++.  Several system tools on Darwin use(d) libc++
and that has caused wrong or crashed test output.  In principle,
LD_LIBRARY_PATH on Linux has the same issue - although perhaps there is
less tendency to default to use of shared dependent libs.

Ideally, one would have several environment paths, and some way to use
the appropriate one at the appropriate time.  I experimented with this
as a solution to both this and the following problem, but it proved
unrealistic - since the process would have to be applied to all relevant
OSS projects using auto-tools to be safe - and mostly the uninstalled
use of libraries is a GCC build-time issue.

===== Problem #2

A change in security policy for Darwin means that DYLD_LIBRARY_PATH is
now removed from the environment for all system tools (e.g. /usr/sh, env
etc).  This means that for all realistic build steps that use any system
utility (like sh) will no longer see the the environment runpath and the
only ones available will be those in the libraries.

This breaks GCC's configuration since the steps mentioned above are now
not seeing the newly-built shared libraries, but actually much olders ones
installed on the system.  It means that for all Darwin15+ we misconfigure
libstdc++.

/bin/sh is hardwired into autoconf, one cannot use CONFIG_SHELL to work
around this - because /bin/sh is invoked first, and then passes control to
CONFIG_SHELL.

A second problem is that we cannot bump the SO name for libgcc_s (which
I need to do to solve an EH problem) - since the new SO name is not
available on the system, and therefore none of the stage1+ target configures
will succeed.  This is because the eventual install path is correctly
encoded into the built library, but it is not present at the install
position (and, in general, cannot be installed - since that might not even
be a suitable path on the build system).

This has also meant that we could not do in-tree testing without first
installing the target libraries (which is mostly inconvenient rather than
a show-stopper, but still).

===== Tested solution.

Darwin has the ability to make the runpaths install-position independent.

One sets the library runpath to @rpath/ which essentially means "use the
runpath available at the time we want to load this".

One can then add (potentially multiple) runpaths to the executable, the
built library can be put anywhere convenient - providing we can put that
path into the exe.

For GCC's build, test and install process this means that we need at each
stage to build exes with the runpaths that are relevant to the positions
of the dependent libraries.

To do this, we add an rpath for each of the startfile paths.  While we are
building/testing GCC these correspond to (for example gcc/  or 
<target>/libstdc++/src/.libs etc) and then, after the compiler is installed
at its intended install path - these become /compiler/installation/path/lib
etc.

I have tested this widely on i686, powerpc, x86_64 and aarch64 Darwin over
more than a year.

So patch 1 : provides a spec that expands to -rpath xxx for each xxx in the
startfiles (which means that this works for anything added as -B and thus
the testsuite also works without installing the target libs again).

The remaining patches implement the Darwin changes to build the target
libraries with @rpath runpaths - this is the largest part of the patch
in bytes - because the libtool change expands.

I would like to get this in early in stage 3 so that it has time to be
kicked around before we branch.

OK for master?
(ideally, we'd also backport to open branches because the breakage is
 quite significant)
 
 thanks
 Iain


Iain Sandoe (4):
  Driver : Provide a spec to insert rpaths for compiler lib dirs.
  Darwin : Handle rpaths given on the command line.
  Darwin : Allow for configuring Darwin to use embedded runpath.
  Darwin, Ada : Add loader path as a default rpath.

 configure                         |   5 +
 configure.ac                      |   5 +
 fixincludes/config.h.in           | 204 ---------------------------
 fixincludes/configure             |   2 +-
 gcc/aclocal.m4                    |  50 +++++++
 gcc/ada/gcc-interface/Makefile.in |   2 +
 gcc/config/darwin-driver.c        |  18 +++
 gcc/config/darwin.h               |  11 +-
 gcc/config/darwin.opt             |   4 +
 gcc/configure                     | 157 +++++++++++++++++++--
 gcc/gcc.c                         |  18 +++
 libatomic/Makefile.am             |   6 +-
 libatomic/Makefile.in             |   5 +-
 libatomic/configure               |  82 ++++++++++-
 libatomic/testsuite/Makefile.in   |   1 +
 libbacktrace/configure            |  80 ++++++++++-
 libcc1/Makefile.am                |   9 ++
 libcc1/Makefile.in                |  12 +-
 libcc1/configure                  | 157 +++++++++++++++++++--
 libffi/Makefile.am                |   7 +-
 libffi/Makefile.in                |   6 +-
 libffi/configure                  | 157 +++++++++++++++++++--
 libgcc/config.host                |  22 ++-
 libgcc/config/t-darwin-rpath      |   5 +
 libgcc/config/t-slibgcc-darwin    |  13 +-
 libgfortran/Makefile.am           |   3 +
 libgfortran/Makefile.in           |  30 ++--
 libgfortran/configure             | 155 ++++++++++++++++++--
 libgfortran/configure.ac          |   4 +-
 libgomp/Makefile.am               |   6 +-
 libgomp/Makefile.in               |   3 +-
 libgomp/configure                 | 151 ++++++++++++++++++--
 libitm/Makefile.am                |   5 +-
 libitm/Makefile.in                |   3 +-
 libitm/configure                  | 171 ++++++++++++++++++++---
 libobjc/configure                 |  96 +++++++++++--
 libobjc/configure.ac              |  14 +-
 liboffloadmic/configure           | 199 +++++++++++++++++++++-----
 liboffloadmic/plugin/Makefile.in  |   2 +-
 liboffloadmic/plugin/aclocal.m4   |   2 +-
 liboffloadmic/plugin/configure    | 199 +++++++++++++++++++++-----
 libphobos/configure               | 151 ++++++++++++++++++--
 libphobos/libdruntime/Makefile.am |   5 +-
 libphobos/libdruntime/Makefile.in |   3 +-
 libphobos/src/Makefile.am         |   5 +-
 libphobos/src/Makefile.in         |   3 +-
 libquadmath/Makefile.am           |   6 +-
 libquadmath/Makefile.in           |   4 +-
 libquadmath/configure             | 225 +++++++++++++++++++++++++++++-
 libquadmath/configure.ac          |   2 +
 libsanitizer/asan/Makefile.am     |   6 +-
 libsanitizer/asan/Makefile.in     |   5 +-
 libsanitizer/configure            | 157 +++++++++++++++++++--
 libsanitizer/hwasan/Makefile.am   |   6 +-
 libsanitizer/hwasan/Makefile.in   |   5 +-
 libsanitizer/lsan/Makefile.am     |   7 +-
 libsanitizer/lsan/Makefile.in     |   6 +-
 libsanitizer/tsan/Makefile.am     |   6 +-
 libsanitizer/tsan/Makefile.in     |   5 +-
 libsanitizer/ubsan/Makefile.am    |   6 +-
 libsanitizer/ubsan/Makefile.in    |   5 +-
 libssp/Makefile.am                |   5 +-
 libssp/Makefile.in                |   3 +-
 libssp/configure                  |  82 ++++++++++-
 libstdc++-v3/configure            | 169 +++++++++++++++++++---
 libstdc++-v3/src/Makefile.am      |   6 +-
 libstdc++-v3/src/Makefile.in      |   3 +-
 libtool.m4                        |  64 ++++++++-
 libvtv/configure                  | 171 ++++++++++++++++++++---
 lto-plugin/Makefile.in            |   1 -
 lto-plugin/configure              |  80 ++++++++++-
 zlib/configure                    |  82 ++++++++++-
 72 files changed, 2832 insertions(+), 533 deletions(-)
 create mode 100644 libgcc/config/t-darwin-rpath

-- 
2.24.3 (Apple Git-128)

[PATCH 1/4] Driver : Provide a spec to insert rpaths for compiler lib dirs.

[Iain Sandoe]

This provides a spec to insert "-rpath DDD" for each DDD corresponding
to a compiler startfile directory.  This allows a target to use @rpath
as the install path for libraries, and have the compiler provide the
necessary rpath to handle this.

gcc/ChangeLog:

	* gcc.c (RUNPATH_OPTION): New.
	(do_spec_1): Provide '%P' as a spec to insert rpaths for
	each compiler startfile path.
---
 gcc/gcc.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/gcc/gcc.c b/gcc/gcc.c
index 506c2acc282..7b52d0bcbfd 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -572,6 +572,7 @@ or with constant text in a single argument.
  %l     process LINK_SPEC as a spec.
  %L     process LIB_SPEC as a spec.
  %M     Output multilib_os_dir.
+ %P	Output a RUNPATH_OPTION for each directory in startfile_prefixes.
  %G     process LIBGCC_SPEC as a spec.
  %R     Output the concatenation of target_system_root and
         target_sysroot_suffix.
@@ -1191,6 +1192,10 @@ proper position among the other output files.  */
 # define SYSROOT_HEADERS_SUFFIX_SPEC ""
 #endif
 
+#ifndef RUNPATH_OPTION
+# define RUNPATH_OPTION "-rpath"
+#endif
+
 static const char *asm_debug = ASM_DEBUG_SPEC;
 static const char *asm_debug_option = ASM_DEBUG_OPTION_SPEC;
 static const char *cpp_spec = CPP_SPEC;
@@ -6130,6 +6135,19 @@ do_spec_1 (const char *spec, int inswitch, const char *soft_matched_part)
 	    }
 	    break;
 
+	  case 'P':
+	    {
+	      struct spec_path_info info;
+
+	      info.option = RUNPATH_OPTION;
+	      info.append_len = 0;
+	      info.omit_relative = false;
+	      info.separate_options = true;
+
+	      for_each_path (&startfile_prefixes, true, 0, spec_path, &info);
+	    }
+	    break;
+
 	  case 'e':
 	    /* %efoo means report an error with `foo' as error message
 	       and don't execute any more commands for this file.  */
-- 
2.24.3 (Apple Git-128)

[PATCH 2/4] Darwin : Handle rpaths given on the command line.

[Iain Sandoe]

We want to produce a situation where a default rpath can be added
to each executable (or dylib), but that can be overridden by any
specific rpath provided by the user.

gcc/ChangeLog:

	* config.gcc: Include rpath.opt
	* config/darwin-driver.c (darwin_driver_init): Detect cases
	where the user has added rpaths via a -Wl or -Xlinker command
	and suppress default rpaths in that case.
	* config/darwin.h (DRIVER_SELF_SPECS): Handle -rpath.
	(DARWIN_RPATH_SPEC): New.
	* config/darwin.opt: Add nodefaultrpath option.
---
 gcc/config/darwin-driver.c | 18 ++++++++++++++++++
 gcc/config/darwin.h        | 11 ++++++++++-
 gcc/config/darwin.opt      |  4 ++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/gcc/config/darwin-driver.c b/gcc/config/darwin-driver.c
index 4f0c6bad61f..ccc288f20ce 100644
--- a/gcc/config/darwin-driver.c
+++ b/gcc/config/darwin-driver.c
@@ -281,6 +281,7 @@ darwin_driver_init (unsigned int *decoded_options_count,
   const char *vers_string = NULL;
   bool seen_version_min = false;
   bool seen_sysroot_p = false;
+  bool seen_rpath_p = false;
 
   for (i = 1; i < *decoded_options_count; i++)
     {
@@ -349,6 +350,13 @@ darwin_driver_init (unsigned int *decoded_options_count,
 	  seen_sysroot_p = true;
 	  break;
 
+	case OPT_Xlinker:
+	case OPT_Wl_:
+	  gcc_checking_assert ((*decoded_options)[i].arg);
+	  if (strncmp ((*decoded_options)[i].arg, "-rpath", 6) == 0)
+	    seen_rpath_p = true;
+	  break;
+
 	default:
 	  break;
 	}
@@ -474,4 +482,14 @@ darwin_driver_init (unsigned int *decoded_options_count,
 			  &(*decoded_options)[*decoded_options_count - 1]);
         }
     }
+
+  if (seen_rpath_p)
+    {
+      ++*decoded_options_count;
+      *decoded_options = XRESIZEVEC (struct cl_decoded_option,
+				     *decoded_options,
+				     *decoded_options_count);
+      generate_option (OPT_nodefaultrpath, NULL, 1, CL_DRIVER,
+		       &(*decoded_options)[*decoded_options_count - 1]);
+    }
 }
diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h
index 7ed01efa694..4423933890b 100644
--- a/gcc/config/darwin.h
+++ b/gcc/config/darwin.h
@@ -384,6 +384,7 @@ extern GTY(()) int darwin_ms_struct;
     DARWIN_NOPIE_SPEC \
     DARWIN_RDYNAMIC \
     DARWIN_NOCOMPACT_UNWIND \
+    "%{!r:%{!nostdlib:%{!rpath:%{!nodefaultrpath:%(darwin_rpaths)}}}} " \
     "}}}}}}} %<pie %<no-pie %<rdynamic %<X %<rpath "
 
 /* Spec that controls whether the debug linker is run automatically for
@@ -516,7 +517,8 @@ extern GTY(()) int darwin_ms_struct;
   { "darwin_crt2", DARWIN_CRT2_SPEC },					\
   { "darwin_crt3", DARWIN_CRT3_SPEC },					\
   { "darwin_dylib1", DARWIN_DYLIB1_SPEC },				\
-  { "darwin_bundle1", DARWIN_BUNDLE1_SPEC },
+  { "darwin_bundle1", DARWIN_BUNDLE1_SPEC },				\
+  { "darwin_rpaths", DARWIN_RPATH_SPEC },
 
 #define DARWIN_CRT1_SPEC						\
   "%:version-compare(!> 10.5 mmacosx-version-min= -lcrt1.o)		\
@@ -542,6 +544,13 @@ extern GTY(()) int darwin_ms_struct;
 "%{!static:%:version-compare(< 10.6 mmacosx-version-min= -lbundle1.o)	\
 	   %{fgnu-tm: -lcrttms.o}}"
 
+/* A default rpath, that picks up dependent libraries installed in the same 
+   director as one being loaded.  */
+#define DARWIN_RPATH_SPEC \
+  "%:version-compare(>= 10.5 mmacosx-version-min= -rpath) \
+   %:version-compare(>= 10.5 mmacosx-version-min= @loader_path) \
+   %P "
+
 #ifdef HAVE_AS_MMACOSX_VERSION_MIN_OPTION
 /* Emit macosx version (but only major).  */
 #define ASM_MMACOSX_VERSION_MIN_SPEC \
diff --git a/gcc/config/darwin.opt b/gcc/config/darwin.opt
index d1d1f816912..021d67b17c7 100644
--- a/gcc/config/darwin.opt
+++ b/gcc/config/darwin.opt
@@ -233,6 +233,10 @@ no_dead_strip_inits_and_terms
 Driver RejectNegative
 (Obsolete) Current linkers never dead-strip these items, so the option is not needed.
 
+nodefaultrpath
+Driver RejectNegative
+Do not add a default rpath to executables, modules or dynamic libraries.
+
 nofixprebinding
 Driver RejectNegative
 (Obsolete after 10.3.9) Set MH_NOPREFIXBINDING, in an executable.
-- 
2.24.3 (Apple Git-128)

[PATCH 3/4] Darwin : Allow for configuring Darwin to use embedded runpath.

[Iain Sandoe]

Recent Darwin versions place contraints on the use of run paths
specified in environment variables.  This breaks some assumptions
in the GCC build.

This change allows the user to configure a Darwin build to use
'@rpath/libraryname.dylib' in library names and then to add an
embedded runpath to executables (and libraries with dependents).

The embedded runpath is added by default unless:

1. the user adds an explicit -rpath / -Wl,-rpath,....
2. the user adds '-nodefaultrpath'.

For an installed compiler, it means that any executable built with
that compiler will reference the runtimes installed with the
compiler (equivalent to hard-coding the library path into the name
of the library).

During build-time configurations  any "-B" entries will be added to
the runpath thus the newly-built libraries will be found by exes.

Since the install name is set in libtool, that decision needs to be
available here (but might also cause dependent ones in Makefiles,
so we need to export a conditional).

This facility is not available for Darwin 8 or earlier, however the
existing environment variable runpath does work there.

We default this on for systems where the external DYLD_LIBRARY_PATH
does not work and off for Darwin 8 or earlier.  For systems that can
use either method, if the value is unset, we use the default (which
is currently DYLD_LIBRARY_PATH).

ChangeLog:

	* configure: Regenerate.
	* configure.ac: Do not add default runpaths to GCC exes
	when we are building -static-libstdc++/-static-libgcc (the
	default).
	* libtool.m4: Add 'enable-darwin-at-runpath'.  Act  on the
	enable flag to alter Darwin libraries to use @rpath names.

gcc/ChangeLog:

	* aclocal.m4: Regenerate.
	* configure: Regenerate.

libatomic/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* testsuite/Makefile.in: Regenerate.

libcc1/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

libffi/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

libgcc/ChangeLog:

	* config/t-slibgcc-darwin: Generate libgcc_s
	with an @rpath name.

libgfortran/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths

libgomp/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

libhsail-rt/ChangeLog:

	* configure: Regenerate.

libitm/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

libobjc/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

liboffloadmic/ChangeLog:

	* configure: Regenerate.
	* plugin/Makefile.in: Regenerate.
	* plugin/aclocal.m4: Regenerate.
	* plugin/configure: Regenerate.

libphobos/ChangeLog:

	* configure: Regenerate.
	* libdruntime/Makefile.am: Handle Darwin rpaths.
	* libdruntime/Makefile.in: Regenerate.
	* src/Makefile.am: Handle Darwin rpaths.
	* src/Makefile.in: Regenerate.

libquadmath/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Handle Darwin rpaths.

libsanitizer/ChangeLog:

	* asan/Makefile.am: Handle Darwin rpaths.
	* asan/Makefile.in: Regenerate.
	* configure: Regenerate.
	* hwasan/Makefile.am: Handle Darwin rpaths.
	* hwasan/Makefile.in: Regenerate.
	* lsan/Makefile.am: Handle Darwin rpaths.
	* lsan/Makefile.in: Regenerate.
	* tsan/Makefile.am: Handle Darwin rpaths.
	* tsan/Makefile.in: Regenerate.
	* ubsan/Makefile.am: Handle Darwin rpaths.
	* ubsan/Makefile.in: Regenerate.

libssp/ChangeLog:

	* Makefile.am: Handle Darwin rpaths.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

libstdc++-v3/ChangeLog:

	* configure: Regenerate.
	* src/Makefile.am: Handle Darwin rpaths.
	* src/Makefile.in: Regenerate.

Darwin, libtool : Provide a mechanism to enable embedded rpaths.

We need to be able to build libraries with install names that begin
with @rpath so that we can use rpaths in DSOs that depend on
them.  Since the install name is set in libtool, that decision needs
to be available here (but might also cause dependent ones in
Makefiles, so we need to export a conditional).
---
 configure                         |   5 +
 configure.ac                      |   5 +
 gcc/aclocal.m4                    |  50 +++++++
 gcc/configure                     | 157 +++++++++++++++++++--
 libatomic/Makefile.am             |   6 +-
 libatomic/Makefile.in             |   5 +-
 libatomic/configure               |  82 ++++++++++-
 libatomic/testsuite/Makefile.in   |   1 +
 libbacktrace/configure            |  80 ++++++++++-
 libcc1/Makefile.am                |   9 ++
 libcc1/Makefile.in                |  12 +-
 libcc1/configure                  | 157 +++++++++++++++++++--
 libffi/Makefile.am                |   7 +-
 libffi/Makefile.in                |   6 +-
 libffi/configure                  | 157 +++++++++++++++++++--
 libgcc/config.host                |  22 ++-
 libgcc/config/t-darwin-rpath      |   5 +
 libgcc/config/t-slibgcc-darwin    |  13 +-
 libgfortran/Makefile.am           |   3 +
 libgfortran/Makefile.in           |  30 ++--
 libgfortran/configure             | 155 ++++++++++++++++++--
 libgfortran/configure.ac          |   4 +-
 libgomp/Makefile.am               |   6 +-
 libgomp/Makefile.in               |   3 +-
 libgomp/configure                 | 151 ++++++++++++++++++--
 libitm/Makefile.am                |   5 +-
 libitm/Makefile.in                |   3 +-
 libitm/configure                  | 171 ++++++++++++++++++++---
 libobjc/configure                 |  96 +++++++++++--
 libobjc/configure.ac              |  14 +-
 liboffloadmic/configure           | 199 +++++++++++++++++++++-----
 liboffloadmic/plugin/Makefile.in  |   2 +-
 liboffloadmic/plugin/aclocal.m4   |   2 +-
 liboffloadmic/plugin/configure    | 199 +++++++++++++++++++++-----
 libphobos/configure               | 151 ++++++++++++++++++--
 libphobos/libdruntime/Makefile.am |   5 +-
 libphobos/libdruntime/Makefile.in |   3 +-
 libphobos/src/Makefile.am         |   5 +-
 libphobos/src/Makefile.in         |   3 +-
 libquadmath/Makefile.am           |   6 +-
 libquadmath/Makefile.in           |   4 +-
 libquadmath/configure             | 225 +++++++++++++++++++++++++++++-
 libquadmath/configure.ac          |   2 +
 libsanitizer/asan/Makefile.am     |   6 +-
 libsanitizer/asan/Makefile.in     |   5 +-
 libsanitizer/configure            | 157 +++++++++++++++++++--
 libsanitizer/hwasan/Makefile.am   |   6 +-
 libsanitizer/hwasan/Makefile.in   |   5 +-
 libsanitizer/lsan/Makefile.am     |   7 +-
 libsanitizer/lsan/Makefile.in     |   6 +-
 libsanitizer/tsan/Makefile.am     |   6 +-
 libsanitizer/tsan/Makefile.in     |   5 +-
 libsanitizer/ubsan/Makefile.am    |   6 +-
 libsanitizer/ubsan/Makefile.in    |   5 +-
 libssp/Makefile.am                |   5 +-
 libssp/Makefile.in                |   3 +-
 libssp/configure                  |  82 ++++++++++-
 libstdc++-v3/configure            | 169 +++++++++++++++++++---
 libstdc++-v3/src/Makefile.am      |   6 +-
 libstdc++-v3/src/Makefile.in      |   3 +-
 libtool.m4                        |  64 ++++++++-
 libvtv/configure                  | 171 ++++++++++++++++++++---
 lto-plugin/Makefile.in            |   1 -
 lto-plugin/configure              |  80 ++++++++++-
 zlib/configure                    |  82 ++++++++++-
 67 files changed, 2780 insertions(+), 532 deletions(-)
 create mode 100644 libgcc/config/t-darwin-rpath

diff --git a/configure.ac b/configure.ac
index bed60bcaf72..bd79a2ffcb9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1769,6 +1769,11 @@ AC_ARG_WITH(boot-ldflags,
  if test "$poststage1_libs" = ""; then
    poststage1_ldflags="-static-libstdc++ -static-libgcc"
  fi])
+if test "x$enable_darwin_at_rpath" = "xyes"; then
+  if test "x$host_shared" != "xyes"; then 
+    poststage1_ldflags="$poststage1_ldflags -nodefaultrpath"
+  fi
+fi 
 AC_SUBST(poststage1_ldflags)
 
 # GCC GRAPHITE dependency isl.


diff --git a/libatomic/Makefile.am b/libatomic/Makefile.am
index 0f3cd6f7121..cde856e532e 100644
--- a/libatomic/Makefile.am
+++ b/libatomic/Makefile.am
@@ -65,8 +65,12 @@ libatomic_version_script =
 libatomic_version_dep =
 endif
 libatomic_version_info = -version-info $(libtool_VERSION)
+if ENABLE_DARWIN_AT_RPATH
+libatomic_darwin_rpath = -Wl,-rpath,@loader_path
+endif
 
-libatomic_la_LDFLAGS = $(libatomic_version_info) $(libatomic_version_script) $(lt_host_flags)
+libatomic_la_LDFLAGS = $(libatomic_version_info) $(libatomic_version_script) \
+	$(lt_host_flags) $(libatomic_darwin_rpath) 
 libatomic_la_SOURCES = gload.c gstore.c gcas.c gexch.c glfree.c lock.c init.c \
 	fenv.c fence.c flag.c
 
diff --git a/libcc1/Makefile.am b/libcc1/Makefile.am
index 49a9543ea7d..aa07d5923bb 100644
--- a/libcc1/Makefile.am
+++ b/libcc1/Makefile.am
@@ -55,6 +55,9 @@ marshall_c_source = marshall-c.hh
 marshall_cxx_source = marshall-cp.hh
 
 libcc1plugin_la_LDFLAGS = -module -export-symbols $(srcdir)/libcc1plugin.sym
+if ENABLE_DARWIN_AT_RPATH
+libcc1plugin_la_LDFLAGS += -Wl,-rpath,@loader_path
+endif
 libcc1plugin_la_SOURCES = libcc1plugin.cc context.cc context.hh \
 	$(shared_source) $(marshall_c_source)
 libcc1plugin.lo_CPPFLAGS = $(CPPFLAGS_FOR_C)
@@ -65,6 +68,9 @@ libcc1plugin_la_LINK = $(LIBTOOL) --tag=CXX $(AM_LIBTOOLFLAGS) \
 	$(CXXFLAGS) $(libcc1plugin_la_LDFLAGS) $(LTLDFLAGS) -o $@
 
 libcp1plugin_la_LDFLAGS = -module -export-symbols $(srcdir)/libcp1plugin.sym
+if ENABLE_DARWIN_AT_RPATH
+libcp1plugin_la_LDFLAGS += -Wl,-rpath,@loader_path
+endif
 libcp1plugin_la_SOURCES = libcp1plugin.cc context.cc context.hh \
 	$(shared_source) $(marshall_cxx_source)
 libcp1plugin.lo_CPPFLAGS = $(CPPFLAGS_FOR_CXX)
@@ -76,6 +82,9 @@ libcp1plugin_la_LINK = $(LIBTOOL) --tag=CXX $(AM_LIBTOOLFLAGS) \
 
 LTLDFLAGS = $(shell $(SHELL) $(top_srcdir)/../libtool-ldflags $(LDFLAGS))
 libcc1_la_LDFLAGS = -module -export-symbols $(srcdir)/libcc1.sym
+if ENABLE_DARWIN_AT_RPATH
+libcc1_la_LDFLAGS += -Wl,-rpath,@loader_path
+endif
 libcc1_la_SOURCES = findcomp.cc libcc1.cc libcp1.cc \
 		compiler.cc compiler.hh names.cc names.hh $(shared_source) \
 		$(marshall_c_source) $(marshall_cxx_source)

diff --git a/libffi/Makefile.am b/libffi/Makefile.am
index c6d6f849c53..d2ae0c04c7b 100644
--- a/libffi/Makefile.am
+++ b/libffi/Makefile.am
@@ -214,7 +214,12 @@ libffi.map: $(top_srcdir)/libffi.map.in
 	$(COMPILE) -D$(TARGET) -DGENERATE_LIBFFI_MAP \
 	 -E -x assembler-with-cpp -o $@ $(top_srcdir)/libffi.map.in
 
-libffi_la_LDFLAGS = -no-undefined $(libffi_version_info) $(libffi_version_script) $(LTLDFLAGS) $(AM_LTLDFLAGS)
+if ENABLE_DARWIN_AT_RPATH
+libffi_darwin_rpath = -Wl,-rpath,@loader_path
+endif
+libffi_la_LDFLAGS = -no-undefined $(libffi_version_info) \
+	$(libffi_version_script) $(LTLDFLAGS) $(AM_LTLDFLAGS) \
+	$(libffi_darwin_rpath)
 libffi_la_DEPENDENCIES = $(libffi_la_LIBADD) $(libffi_version_dep)
 
 AM_CPPFLAGS = -I. -I$(top_srcdir)/include -Iinclude -I$(top_srcdir)/src

diff --git a/libffi/Makefile.in b/libffi/Makefile.in
index 5524a6a571e..34e77a45d1a 100644
--- a/libffi/Makefile.in
+++ b/libffi/Makefile.in
@@ -597,7 +597,11 @@ AM_CFLAGS = -Wall -g -fexceptions $(CET_FLAGS) $(am__append_2)
 @LIBFFI_BUILD_VERSIONED_SHLIB_GNU_TRUE@@LIBFFI_BUILD_VERSIONED_SHLIB_TRUE@libffi_version_dep = libffi.map
 @LIBFFI_BUILD_VERSIONED_SHLIB_SUN_TRUE@@LIBFFI_BUILD_VERSIONED_SHLIB_TRUE@libffi_version_dep = libffi.map-sun
 libffi_version_info = -version-info `grep -v '^\#' $(srcdir)/libtool-version`
-libffi_la_LDFLAGS = -no-undefined $(libffi_version_info) $(libffi_version_script) $(LTLDFLAGS) $(AM_LTLDFLAGS)
+@ENABLE_DARWIN_AT_RPATH_TRUE@libffi_darwin_rpath = -Wl,-rpath,@loader_path
+libffi_la_LDFLAGS = -no-undefined $(libffi_version_info) \
+	$(libffi_version_script) $(LTLDFLAGS) $(AM_LTLDFLAGS) \
+	$(libffi_darwin_rpath)
+
 libffi_la_DEPENDENCIES = $(libffi_la_LIBADD) $(libffi_version_dep)
 AM_CPPFLAGS = -I. -I$(top_srcdir)/include -Iinclude -I$(top_srcdir)/src
 AM_CCASFLAGS = $(AM_CPPFLAGS) $(CET_FLAGS)


diff --git a/libgcc/config.host b/libgcc/config.host
index 168535b1780..5306a509ff8 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -214,7 +214,27 @@ esac
 case ${host} in
 *-*-darwin*)
   asm_hidden_op=.private_extern
-  tmake_file="$tmake_file t-darwin ${cpu_type}/t-darwin t-libgcc-pic t-slibgcc-darwin"
+  tmake_file="$tmake_file t-darwin ${cpu_type}/t-darwin "
+  tmake_file="$tmake_file t-libgcc-pic t-slibgcc-darwin "
+  # We are not using libtool to build the libs here, so we need to replicate
+  # a little of the logic around setting Darwin rpaths.  Setting an explicit
+  # yes or no is honoured, otherwise we choose a suitable default.
+  # Sadly, this has to be kept in line with the rules in libtool.m4.
+  if test "x$enable_darwin_at_rpath" = "xyes"; then
+    tmake_file="$tmake_file t-darwin-rpath "
+  elif test "x$enable_darwin_at_rpath" = "x"; then
+    echo "enable_darwin_at_rpath is unset" 1>&2
+    case ${host} in
+      *-darwin[45678]*) ;;
+      *-darwin9* | *-darwin1[01234]*) ;; # We might default these on later.
+      *-darwin*)
+        echo "but is needed after macOS 10.11 (setting it on)" 1>&2
+        tmake_file="$tmake_file t-darwin-rpath "
+        ;;
+    esac
+  else
+    echo "enable_darwin_at_rpath is '$enable_darwin_at_rpath'" 1>&2
+  fi
   extra_parts="crt3.o libd10-uwfef.a crttms.o crttme.o"
   ;;
 *-*-dragonfly*)

diff --git a/libgcc/config/t-darwin-rpath b/libgcc/config/t-darwin-rpath
new file mode 100644
index 00000000000..7cf63d9cb6b
--- /dev/null
+++ b/libgcc/config/t-darwin-rpath
@@ -0,0 +1,5 @@
+# Use @rpath and add a search path to exes and dylibs that depend on this.
+SHLIB_RPATH = @rpath
+
+# Which does not work for Darwin < 9
+HOST_LIBGCC2_CFLAGS += -mmacosx-version-min=10.5
diff --git a/libgcc/config/t-slibgcc-darwin b/libgcc/config/t-slibgcc-darwin
index bd1e9631c17..b800a9aa175 100644
--- a/libgcc/config/t-slibgcc-darwin
+++ b/libgcc/config/t-slibgcc-darwin
@@ -10,17 +10,16 @@ SHLIB_OBJS = @shlib_objs@
 SHLIB_DIR = @multilib_dir@
 SHLIB_LC = -lc
 
-# Darwin only searches in /usr/lib for shared libraries, not in subdirectories,
-# so the libgcc variants have different names not different locations.
-# Note that this version is used for the loader, not the linker; the linker
-# uses the stub versions named by the versioned members of $(INSTALL_FILES).
+# Instead of using @shlib_slibdir@, use @rpath and add a search path to exes
+# and dylibs that depend on this.
+SHLIB_RPATH = @shlib_slibdir@
 
 SHLIB_LINK = $(CC) $(LIBGCC2_CFLAGS) $(LDFLAGS) -dynamiclib -nodefaultlibs \
-	-install_name @shlib_slibdir@/$(SHLIB_INSTALL_NAME) \
+	-install_name $(SHLIB_RPATH)/$(SHLIB_INSTALL_NAME) \
 	-single_module -o $(SHLIB_DIR)/$(SHLIB_SONAME) \
 	-Wl,-exported_symbols_list,$(SHLIB_MAP) \
-	$(SHLIB_VERSTRING) \
-	@multilib_flags@ $(SHLIB_OBJS) $(SHLIB_LC)
+	$(SHLIB_VERSTRING) -nodefaultrpath \
+	@multilib_flags@ @shlib_objs@ $(SHLIB_LC)
 
 SHLIB_MKMAP = $(srcdir)/mkmap-flat.awk
 SHLIB_MKMAP_OPTS = -v leading_underscore=1

diff --git a/libgfortran/Makefile.am b/libgfortran/Makefile.am
index 008f2e7549c..e036b88119e 100644
--- a/libgfortran/Makefile.am
+++ b/libgfortran/Makefile.am
@@ -29,6 +29,9 @@ else
 version_arg =
 version_dep =
 endif
+if ENABLE_DARWIN_AT_RPATH
+extra_ldflags_libgfortran += -Wl,-rpath,@loader_path
+endif
 
 gfor_c_HEADERS = ISO_Fortran_binding.h
 gfor_cdir = $(libdir)/gcc/$(target_alias)/$(gcc_version)/include

diff --git a/libgomp/Makefile.am b/libgomp/Makefile.am
index f8b2a06d63e..4dca7e532bf 100644
--- a/libgomp/Makefile.am
+++ b/libgomp/Makefile.am
@@ -53,9 +53,13 @@ else
 libgomp_version_script =
 libgomp_version_dep =
 endif
+
 libgomp_version_info = -version-info $(libtool_VERSION)
+if ENABLE_DARWIN_AT_RPATH
+libgomp_darwin_rpath = -Wl,-rpath,@loader_path
+endif
 libgomp_la_LDFLAGS = $(libgomp_version_info) $(libgomp_version_script) \
-        $(lt_host_flags)
+        $(lt_host_flags) $(libgomp_darwin_rpath)
 libgomp_la_DEPENDENCIES = $(libgomp_version_dep)
 libgomp_la_LINK = $(LINK) $(libgomp_la_LDFLAGS)
 
diff --git a/libgomp/Makefile.in b/libgomp/Makefile.in
index 22cb2136a08..7a45add6a36 100644
--- a/libgomp/Makefile.in
+++ b/libgomp/Makefile.in
@@ -546,8 +546,9 @@ nodist_toolexeclib_HEADERS = libgomp.spec
 @LIBGOMP_BUILD_VERSIONED_SHLIB_GNU_TRUE@@LIBGOMP_BUILD_VERSIONED_SHLIB_TRUE@libgomp_version_dep = libgomp.ver
 @LIBGOMP_BUILD_VERSIONED_SHLIB_SUN_TRUE@@LIBGOMP_BUILD_VERSIONED_SHLIB_TRUE@libgomp_version_dep = libgomp.ver-sun
 libgomp_version_info = -version-info $(libtool_VERSION)
+@ENABLE_DARWIN_AT_RPATH_TRUE@libgomp_darwin_rpath = -Wl,-rpath,@loader_path
 libgomp_la_LDFLAGS = $(libgomp_version_info) $(libgomp_version_script) \
-        $(lt_host_flags)
+        $(lt_host_flags) $(libgomp_darwin_rpath)
 
 libgomp_la_DEPENDENCIES = $(libgomp_version_dep)
 libgomp_la_LINK = $(LINK) $(libgomp_la_LDFLAGS)

diff --git a/libitm/Makefile.am b/libitm/Makefile.am
index 3f31ad30556..053a54fb093 100644
--- a/libitm/Makefile.am
+++ b/libitm/Makefile.am
@@ -54,7 +54,10 @@ libitm_version_info = -version-info $(libtool_VERSION)
 # want or need libstdc++.
 libitm_la_DEPENDENCIES = $(libitm_version_dep)
 libitm_la_LINK = $(LINK) $(libitm_la_LDFLAGS)
-libitm_la_LDFLAGS = $(libitm_version_info) $(libitm_version_script)
+if ENABLE_DARWIN_AT_RPATH
+libitm_darwin_rpath = -Wl,-rpath,@loader_path
+endif
+libitm_la_LDFLAGS = $(libitm_version_info) $(libitm_version_script) $(libitm_darwin_rpath)
 
 libitm_la_SOURCES = \
 	aatree.cc alloc.cc alloc_c.cc alloc_cpp.cc barrier.cc beginend.cc \


diff --git a/libobjc/configure.ac b/libobjc/configure.ac
index c1104db85f0..92b77dc1700 100644
--- a/libobjc/configure.ac
+++ b/libobjc/configure.ac
@@ -148,10 +148,20 @@ m4_rename_force([real_PRECIOUS],[_AC_ARG_VAR_PRECIOUS])
 # extra LD Flags which are required for targets
 ACX_LT_HOST_FLAGS
 case "${host}" in
-  *-darwin*)
-    # Darwin needs -single_module when linking libobjc
+  *-darwin[[4567]]*)
+    # Earlier Darwin versions need -single_module when linking libobjc; they
+    # do not support @rpath.
     extra_ldflags_libobjc='$(lt_host_flags) -Wl,-single_module'
     ;;
+  *-darwin*)
+    # Otherwise, single_module is the default and multi-module is ignored and
+    # obsolete.
+    if test "x$enable_darwin_at_rpath" = "xyes"; then
+      extra_ldflags_libobjc='$(lt_host_flags) -Wl,-rpath,@loader_path'
+    else
+      extra_ldflags_libobjc='$(lt_host_flags)'
+    fi
+    ;;
   *-cygwin*|*-mingw*)
     # Tell libtool to build DLLs on Windows
     extra_ldflags_libobjc='$(lt_host_flags)'


diff --git a/libsanitizer/asan/Makefile.am b/libsanitizer/asan/Makefile.am
index 4f802f723d6..86ac110466b 100644
--- a/libsanitizer/asan/Makefile.am
+++ b/libsanitizer/asan/Makefile.am
@@ -60,7 +60,11 @@ libasan_la_LIBADD += $(top_builddir)/libbacktrace/libsanitizer_libbacktrace.la
 endif
 libasan_la_LIBADD += $(LIBSTDCXX_RAW_CXX_LDFLAGS)
 
-libasan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` $(link_libasan)
+if ENABLE_DARWIN_AT_RPATH
+libasan_darwin_rpath = -Wl,-rpath,@loader_path
+endif
+libasan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
+	$(link_libasan) $(libasan_darwin_rpath)
 
 libasan_preinit.o: asan_preinit.o
 	cp $< $@

diff --git a/libsanitizer/hwasan/Makefile.am b/libsanitizer/hwasan/Makefile.am
index e12c0a0ce71..d73bcac782a 100644
--- a/libsanitizer/hwasan/Makefile.am
+++ b/libsanitizer/hwasan/Makefile.am
@@ -46,7 +46,11 @@ libhwasan_la_LIBADD += $(top_builddir)/libbacktrace/libsanitizer_libbacktrace.la
 endif
 libhwasan_la_LIBADD += $(LIBSTDCXX_RAW_CXX_LDFLAGS)
 
-libhwasan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` $(link_libhwasan)
+if ENABLE_DARWIN_AT_RPATH
+libhwasan_darwin_rpath = -Wl,-rpath,@loader_path
+endif
+libhwasan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
+	$(link_libhwasan) $(libhwasan_darwin_rpath)
 
 # Work around what appears to be a GNU make bug handling MAKEFLAGS
 # values defined in terms of make variables, as is the case for CC and

diff --git a/libsanitizer/lsan/Makefile.am b/libsanitizer/lsan/Makefile.am
index 6ff28ff5eea..34a9f7b9977 100644
--- a/libsanitizer/lsan/Makefile.am
+++ b/libsanitizer/lsan/Makefile.am
@@ -41,8 +41,11 @@ if LIBBACKTRACE_SUPPORTED
 liblsan_la_LIBADD += $(top_builddir)/libbacktrace/libsanitizer_libbacktrace.la
 endif
 liblsan_la_LIBADD += $(LIBSTDCXX_RAW_CXX_LDFLAGS)
-liblsan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` $(link_liblsan)
-
+if ENABLE_DARWIN_AT_RPATH
+liblsan_darwin_rpath = -Wl,-rpath,@loader_path
+endif
+liblsan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
+	$(link_liblsan) $(liblsan_darwin_rpath)
 liblsan_preinit.o: lsan_preinit.o
 	cp $< $@
 

diff --git a/libsanitizer/tsan/Makefile.am b/libsanitizer/tsan/Makefile.am
index ae588a67df6..eed8f321b3c 100644
--- a/libsanitizer/tsan/Makefile.am
+++ b/libsanitizer/tsan/Makefile.am
@@ -58,7 +58,11 @@ libtsan_la_LIBADD += $(top_builddir)/libbacktrace/libsanitizer_libbacktrace.la
 libtsan_la_DEPENDENCIES +=$(top_builddir)/libbacktrace/libsanitizer_libbacktrace.la
 endif
 libtsan_la_LIBADD += $(LIBSTDCXX_RAW_CXX_LDFLAGS)
-libtsan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` $(link_libtsan)
+if ENABLE_DARWIN_AT_RPATH
+libtsan_darwin_rpath = -Wl,-rpath,@loader_path
+endif
+libtsan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
+	$(link_libtsan) $(libtsan_darwin_rpath)
 
 libtsan_preinit.o: tsan_preinit.o
 	cp $< $@

diff --git a/libsanitizer/ubsan/Makefile.am b/libsanitizer/ubsan/Makefile.am
index d480f26adc0..0bfae37ba09 100644
--- a/libsanitizer/ubsan/Makefile.am
+++ b/libsanitizer/ubsan/Makefile.am
@@ -36,7 +36,11 @@ if LIBBACKTRACE_SUPPORTED
 libubsan_la_LIBADD += $(top_builddir)/libbacktrace/libsanitizer_libbacktrace.la
 endif
 libubsan_la_LIBADD += $(LIBSTDCXX_RAW_CXX_LDFLAGS)
-libubsan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` $(link_libubsan)
+if ENABLE_DARWIN_AT_RPATH
+libubsan_darwin_rpath = -Wl,-rpath,@loader_path
+endif
+libubsan_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
+	$(link_libubsan) $(libubsan_darwin_rpath)
 
 # Use special rules for files that require RTTI support.
 ubsan_handlers_cxx.% ubsan_type_hash.% ubsan_type_hash_itanium.% : AM_CXXFLAGS += -frtti

diff --git a/libssp/Makefile.am b/libssp/Makefile.am
index 6045c320cfa..1155e987a9b 100644
--- a/libssp/Makefile.am
+++ b/libssp/Makefile.am
@@ -49,8 +49,11 @@ libssp_la_SOURCES = \
 	vsnprintf-chk.c vsprintf-chk.c
 libssp_la_LIBADD = 
 libssp_la_DEPENDENCIES = $(version_dep) $(libssp_la_LIBADD)
+if ENABLE_DARWIN_AT_RPATH
+libssp_darwin_rpath = -Wl,-rpath,@loader_path
+endif
 libssp_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
-		    $(version_arg) $(lt_host_flags)
+		    $(version_arg) $(lt_host_flags) $(libssp_darwin_rpath)
 
 libssp_nonshared_la_SOURCES = \
 	ssp-local.c

diff --git a/libstdc++-v3/src/Makefile.am b/libstdc++-v3/src/Makefile.am
index f27d3f8c87e..77e7cedb17a 100644
--- a/libstdc++-v3/src/Makefile.am
+++ b/libstdc++-v3/src/Makefile.am
@@ -122,8 +122,12 @@ libstdc___la_DEPENDENCIES = \
 	$(top_builddir)/src/c++17/libc++17convenience.la \
 	$(top_builddir)/src/c++20/libc++20convenience.la
 
+if ENABLE_DARWIN_AT_RPATH
+libstdc___darwin_rpath = -Wl,-rpath,@loader_path
+endif
+
 libstdc___la_LDFLAGS = \
-	-version-info $(libtool_VERSION) ${version_arg} -lm
+	-version-info $(libtool_VERSION) ${version_arg} -lm $(libstdc___darwin_rpath)
 
 libstdc___la_LINK = $(CXXLINK) $(libstdc___la_LDFLAGS) $(lt_host_flags)
 
diff --git a/libstdc++-v3/src/Makefile.in b/libstdc++-v3/src/Makefile.in
index 05b25ed5e9d..c4eb9e8c546 100644
--- a/libstdc++-v3/src/Makefile.in
+++ b/libstdc++-v3/src/Makefile.in
@@ -534,8 +534,9 @@ libstdc___la_DEPENDENCIES = \
 	$(top_builddir)/src/c++17/libc++17convenience.la \
 	$(top_builddir)/src/c++20/libc++20convenience.la
 
+@ENABLE_DARWIN_AT_RPATH_TRUE@libstdc___darwin_rpath = -Wl,-rpath,@loader_path
 libstdc___la_LDFLAGS = \
-	-version-info $(libtool_VERSION) ${version_arg} -lm
+	-version-info $(libtool_VERSION) ${version_arg} -lm $(libstdc___darwin_rpath)
 
 libstdc___la_LINK = $(CXXLINK) $(libstdc___la_LDFLAGS) $(lt_host_flags)
 @GLIBCXX_LDBL_ALT128_COMPAT_FALSE@@GLIBCXX_LDBL_COMPAT_TRUE@LTCXXCOMPILE64 = $(LTCXXCOMPILE)

diff --git a/libtool.m4 b/libtool.m4
index 17f8e5f3074..b474089fc3e 100644
--- a/libtool.m4
+++ b/libtool.m4
@@ -1039,6 +1039,47 @@ _LT_EOF
 m4_defun([_LT_DARWIN_LINKER_FEATURES],
 [
   m4_require([_LT_REQUIRED_DARWIN_CHECKS])
+
+  # Publish an arg to allow the user to select that Darwin host (and target)
+  # libraries should be given install-names like @rpath/libfoo.dylib.  This
+  # requires that the user of the library then adds an 'rpath' to the DSO that
+  # needs access.
+  # NOTE: there are defaults below, for systems that support rpaths.  The person
+  # configuring can override the defaults for any system version that supports
+  # them - they are, however, forced off for system versions without support.
+  AC_ARG_ENABLE([darwin-at-rpath],
+    AS_HELP_STRING([--enable-darwin-at-path],
+      [install libraries with @rpath/library-name, requires rpaths to be added to executables]),
+  [if test "x$enable_darwin_at_rpath" = "xyes"; then
+    # This is not supported before macOS 10.5 / Darwin9.
+    case ${MACOSX_DEPLOYMENT_TARGET-UNSET},$host_os in
+      UNSET,darwin[[45678]]*|UNSET,rhapsody*|10.[[01234]][[,.]]*)
+	echo "WARNING: Darwin @rpath library names are incompatible with macOS versions earlier than 10.5 (rpaths disabled)" 1>&AS_MESSAGE_LOG_FD
+	enable_darwin_at_rpath=no
+      ;;
+    esac
+   fi],
+  [case ${MACOSX_DEPLOYMENT_TARGET-UNSET},$host_os in
+    # As above, before 10.5 / Darwin9 this does not work.
+     UNSET,darwin[[45678]]*|UNSET,rhapsody*|10.[[01234]][[,.]]*)
+       enable_darwin_at_rpath=no
+       ;;
+
+    # We cannot build and test reliably on macOS 10.11+ (Darwin15+) without use
+    # of rpaths, since runpaths set via DYLD_LIBRARY_PATH are elided by key
+    # system executables (e.g. /bin/sh).  Force rpaths on for these systems.
+      UNSET,darwin1[[56789]]*|UNSET,darwin2*|10.1[[123456789]][[,.]]*|1[[12]].*[[,.]]* )
+      echo "@rpath library names are needed on macOS versions later than 10.11 (rpaths enabled)" 1>&AS_MESSAGE_LOG_FD
+      enable_darwin_at_rpath=yes
+      ;;
+    # NOTE: we are not (yet) doing anything for 10.5 .. 10.10, since they can
+    # work with either DYLD_LIBRARY_PATH or embedded rpaths.
+
+    esac
+  ])
+
+  AM_CONDITIONAL([ENABLE_DARWIN_AT_RPATH], [test "x$enable_darwin_at_rpath" = "xyes"])
+
   _LT_TAGVAR(archive_cmds_need_lc, $1)=no
   _LT_TAGVAR(hardcode_direct, $1)=no
   _LT_TAGVAR(hardcode_automatic, $1)=yes
@@ -1056,13 +1097,26 @@ m4_defun([_LT_DARWIN_LINKER_FEATURES],
   esac
   if test "$_lt_dar_can_shared" = "yes"; then
     output_verbose_link_cmd=func_echo_all
-    _LT_TAGVAR(archive_cmds, $1)="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod${_lt_dsymutil}"
-    _LT_TAGVAR(module_cmds, $1)="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dsymutil}"
-    _LT_TAGVAR(archive_expsym_cmds, $1)="sed 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring ${_lt_dar_single_mod}${_lt_dar_export_syms}${_lt_dsymutil}"
-    _LT_TAGVAR(module_expsym_cmds, $1)="sed -e 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dar_export_syms}${_lt_dsymutil}"
+    if test "x$enable_darwin_at_rpath" = "xyes"; then
+      echo "using Darwin @rpath" 1>&AS_MESSAGE_LOG_FD
+      _LT_TAGVAR(archive_cmds, $1)="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name @rpath/\$soname \$verstring ${_lt_dsymutil}"
+      _LT_TAGVAR(module_cmds, $1)="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dsymutil}"
+      _LT_TAGVAR(archive_expsym_cmds, $1)="sed 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name @rpath/\$soname \$verstring ${_lt_dar_export_syms}${_lt_dsymutil}"
+      _LT_TAGVAR(module_expsym_cmds, $1)="sed -e 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dar_export_syms}${_lt_dsymutil}"
+    else
+      echo "NOT using Darwin @rpath" 1>&AS_MESSAGE_LOG_FD
+      _LT_TAGVAR(archive_cmds, $1)="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod${_lt_dsymutil}"
+      _LT_TAGVAR(module_cmds, $1)="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dsymutil}"
+      _LT_TAGVAR(archive_expsym_cmds, $1)="sed 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring ${_lt_dar_single_mod}${_lt_dar_export_syms}${_lt_dsymutil}"
+      _LT_TAGVAR(module_expsym_cmds, $1)="sed -e 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags${_lt_dar_export_syms}${_lt_dsymutil}"
+    fi
     m4_if([$1], [CXX],
 [   if test "$lt_cv_apple_cc_single_mod" != "yes"; then
-      _LT_TAGVAR(archive_cmds, $1)="\$CC -r -keep_private_externs -nostdlib -o \${lib}-master.o \$libobjs~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \${lib}-master.o \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring${_lt_dsymutil}"
+      if test "x$enable_darwin_at_rpath" = "xyes"; then
+        _LT_TAGVAR(archive_cmds, $1)="\$CC -r -keep_private_externs -nostdlib -o \${lib}-master.o \$libobjs~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \${lib}-master.o \$deplibs \$compiler_flags -install_name @rpath/\$soname \$verstring${_lt_dsymutil}"
+      else
+        _LT_TAGVAR(archive_cmds, $1)="\$CC -r -keep_private_externs -nostdlib -o \${lib}-master.o \$libobjs~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \${lib}-master.o \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring${_lt_dsymutil}"
+      fi
       _LT_TAGVAR(archive_expsym_cmds, $1)="sed 's,^,_,' < \$export_symbols > \$output_objdir/\${libname}-symbols.expsym~\$CC -r -keep_private_externs -nostdlib -o \${lib}-master.o \$libobjs~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \${lib}-master.o \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring${_lt_dar_export_syms}${_lt_dsymutil}"
     fi
 ],[])

diff --git a/lto-plugin/Makefile.in b/lto-plugin/Makefile.in
index f8df31bb1e8..591a1624e98 100644
--- a/lto-plugin/Makefile.in
+++ b/lto-plugin/Makefile.in
@@ -323,7 +323,6 @@ prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
 real_target_noncanonical = @real_target_noncanonical@
-runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@

-- 
2.24.3 (Apple Git-128)

[PATCH 4/4] Darwin, Ada : Add loader path as a default rpath.

[Iain Sandoe]

Allow the Ada runtimes to find GCC runtimes relative to their non-
standard install positions.

gcc/ada/
	* gcc-interface/Makefile.in: Add @loader_path runpaths to the
	libgnat and libgnarl shared library builds.
	
---
 gcc/ada/gcc-interface/Makefile.in | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/ada/gcc-interface/Makefile.in b/gcc/ada/gcc-interface/Makefile.in
index 53d0739470a..bffe9de4c89 100644
--- a/gcc/ada/gcc-interface/Makefile.in
+++ b/gcc/ada/gcc-interface/Makefile.in
@@ -788,6 +788,7 @@ gnatlib-shared-darwin:
 		$(GNATRTL_NONTASKING_OBJS) $(LIBGNAT_OBJS) \
 		$(SO_OPTS) \
 		-Wl,-install_name,@rpath/libgnat$(hyphen)$(LIBRARY_VERSION)$(soext) \
+		-Wl,-rpath,@loader_path \
 		$(MISCLIB)
 	cd $(RTSDIR); `echo "$(GCC_FOR_TARGET)" \
                 | sed -e 's,\./xgcc,../../xgcc,' -e 's,-B\./,-B../../,'` -dynamiclib $(PICFLAG_FOR_TARGET) \
@@ -795,6 +796,7 @@ gnatlib-shared-darwin:
 		$(GNATRTL_TASKING_OBJS) \
 		$(SO_OPTS) \
 		-Wl,-install_name,@rpath/libgnarl$(hyphen)$(LIBRARY_VERSION)$(soext) \
+		-Wl,-rpath,@loader_path \
 		$(THREADSLIB) -Wl,libgnat$(hyphen)$(LIBRARY_VERSION)$(soext)
 	cd $(RTSDIR); $(LN_S) libgnat$(hyphen)$(LIBRARY_VERSION)$(soext) \
 		libgnat$(soext)
-- 
2.24.3 (Apple Git-128)

Re: [PATCH 3/4] Darwin : Allow for configuring Darwin to use embedded runpath.

[Joseph Myers]

On Wed, 17 Nov 2021, Iain Sandoe via Gcc-patches wrote:

> 	* libtool.m4: Add 'enable-darwin-at-runpath'.  Act  on the
> 	enable flag to alter Darwin libraries to use @rpath names.

To confirm: has this been sent to upstream libtool (which has recently 
acquired a new maintainer, so hopefully might become a bit more active at 
dealing with the backlog of patches)?

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: [PATCH 3/4] Darwin : Allow for configuring Darwin to use embedded runpath.

[Iain Sandoe]

> On 17 Nov 2021, at 22:50, Joseph Myers <joseph@codesourcery.com> wrote:
> 
> On Wed, 17 Nov 2021, Iain Sandoe via Gcc-patches wrote:
> 
>> 	* libtool.m4: Add 'enable-darwin-at-runpath'.  Act  on the
>> 	enable flag to alter Darwin libraries to use @rpath names.
> 
> To confirm: has this been sent to upstream libtool (which has recently 
> acquired a new maintainer, so hopefully might become a bit more active at 
> dealing with the backlog of patches)?

No. it has not
(a) I was not aware of the new maintainer
(b) the background problem does seem a pretty GCC-specific issue.

If we are going to try and reconcile GCC’s local libtool for more generic Darwin
use, then I fear that is going to take quite significant work over a period of time
(since it will need much more wide testing than GCC).

Having said that, it would be good to have a more up-to-date upstream libtool
the current source has a lot of ancient content - as with all things it’s just a
question of resources.   It’s unlikely to be on my radar in time for GCC12.

Iain

Re: [PATCH 4/4] Darwin, Ada : Add loader path as a default rpath.

[Arnaud Charlet]

> Allow the Ada runtimes to find GCC runtimes relative to their non-
> standard install positions.
> 
> gcc/ada/
> 	* gcc-interface/Makefile.in: Add @loader_path runpaths to the
> 	libgnat and libgnarl shared library builds.

OK, thanks.

Re: [PATCH 3/4] Darwin : Allow for configuring Darwin to use embedded runpath.

[Jonathan Wakely]

On Wed, 17 Nov 2021 at 21:28, Iain Sandoe via Libstdc++ <
libstdc++@gcc.gnu.org> wrote:

> this refers to the libstdc++ changes (mostly a regeneration from the
> libtool
> change) but a small addition to Makefile.am to add @loader_path as a
> default for libstdc++ to find its dependent libs.
>


The libstdc++ part looks OK.

Re: [PATCH 3/4] Darwin : Allow for configuring Darwin to use embedded runpath.

[Joseph Myers]

On Wed, 17 Nov 2021, Iain Sandoe via Gcc-patches wrote:

> If we are going to try and reconcile GCC’s local libtool for more 
> generic Darwin use, then I fear that is going to take quite significant 
> work over a period of time (since it will need much more wide testing 
> than GCC).

The goal isn't any kind of merging GCC's libtool with upstream right now.  
But, once the new maintainer has got through the patch backlog, we'd like 
to be in a position where the starting point for a libtool update in GCC 
is simply taking upstream libtool and reverting libtool commit 
3334f7ed5851ef1e96b052f2984c4acdbf39e20c to deal with a mismatch of 
--with-sysroot interpretations - but not needing any local changes other 
than that reversion.  If each local libtool patch gets submitted upstream 
before being applied to GCC, that reduces the chances of missing some 
significant local change that needs to be reapplied when updating libtool 
(given that GCC is apparently using libtool commit 
2c9c38d8a12eb0a2ce7fe9c3862523026c3d5622 from 2009, it may well be 
nontrivial to figure out whether a given local change is actually relevant 
with a new libtool version or not).

-- 
Joseph S. Myers
joseph@codesourcery.com