gecko-dev/build/autoconf/toolchain.m4
Nick Alexander d56eb2a314 Bug 1489443 - Set GCC_USE_GNU_LD based on linker kind. r=froydnj
The desired outcome of this change is that we'll set
-Wl,--version-script based on linker kind and not on the output of
$LINKER -v.

This is a cheap way to address a simple problem that has a complicated
ideal solution. The underlying issue is that in some situations, when
targeting Android, a macOS system ld is interrogated to determine if
a cross-compiling linker "is GNU ld" and a particular linker feature
is set in that situation. The macOS system ld doesn't pass the "is
GNU ld" test, and the linker feature isn't set; that causes link
failures, even though the actual linker has nothing to do with the
system ld.

The ideal solution is to test for linker capabilities dynamically. We
do a lot of that in old-configure.in, and we don't do any of that in
toolchain.configure. Rather than start testing in
toolchain.configure, we hard-code: a cheap solution to the immediate
problem.

MinGW suffers somewhat from the opposite problem: the linker "is GNU
ld" (compatible), but the linker checks don't happen at all. We hard-code
for MinGW based on the C compiler instead.

Differential Revision: https://phabricator.services.mozilla.com/D8471

--HG--
extra : moz-landing-system : lando
2018-10-17 19:46:03 +00:00

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dnl This Source Code Form is subject to the terms of the Mozilla Public
dnl License, v. 2.0. If a copy of the MPL was not distributed with this
dnl file, You can obtain one at http://mozilla.org/MPL/2.0/.
dnl Several autoconf functions AC_REQUIRE AC_PROG_CPP/AC_PROG_CXXCPP
dnl or AC_HEADER_STDC, meaning they are called even when we don't call
dnl them explicitly.
dnl However, theses checks are not necessary and python configure sets
dnl the corresponding variables already, so just skip those tests
dnl entirely.
define([AC_PROG_CPP],[])
define([AC_PROG_CXXCPP],[])
define([AC_HEADER_STDC], [])
AC_DEFUN([MOZ_TOOL_VARIABLES],
[
GNU_CC=
GNU_CXX=
if test "$CC_TYPE" = "gcc"; then
GNU_CC=1
GNU_CXX=1
fi
CLANG_CC=
CLANG_CXX=
CLANG_CL=
if test "$CC_TYPE" = "clang"; then
GNU_CC=1
GNU_CXX=1
CLANG_CC=1
CLANG_CXX=1
fi
if test "$CC_TYPE" = "clang-cl"; then
CLANG_CL=1
fi
AC_SUBST(CLANG_CXX)
AC_SUBST(CLANG_CL)
])
AC_DEFUN([MOZ_CROSS_COMPILER],
[
echo "cross compiling from $host to $target"
if test -z "$HOST_AR_FLAGS"; then
HOST_AR_FLAGS="$AR_FLAGS"
fi
AC_CHECK_PROGS(HOST_RANLIB, $HOST_RANLIB ranlib, ranlib, :)
AC_CHECK_PROGS(HOST_AR, $HOST_AR ar, ar, :)
dnl AC_CHECK_PROGS manually goes through $PATH, and as such fails to handle
dnl absolute or relative paths. Relative paths wouldn't work anyways, but
dnl absolute paths would. Trick AC_CHECK_PROGS into working in that case by
dnl adding / to PATH. This is temporary until this moves to moz.configure
dnl (soon).
_SAVE_PATH=$PATH
case "${TOOLCHAIN_PREFIX}" in
/*)
PATH="/:$PATH"
;;
esac
AC_PROG_CC
AC_PROG_CXX
AC_CHECK_PROGS(RANLIB, "${TOOLCHAIN_PREFIX}ranlib", :)
AC_CHECK_PROGS(AR, "${TOOLCHAIN_PREFIX}ar", :)
AC_CHECK_PROGS(AS, "${TOOLCHAIN_PREFIX}as", :)
AC_CHECK_PROGS(LIPO, "${TOOLCHAIN_PREFIX}lipo", :)
AC_CHECK_PROGS(STRIP, "${TOOLCHAIN_PREFIX}strip", :)
AC_CHECK_PROGS(WINDRES, "${TOOLCHAIN_PREFIX}windres", :)
AC_CHECK_PROGS(OTOOL, "${TOOLCHAIN_PREFIX}otool", :)
AC_CHECK_PROGS(INSTALL_NAME_TOOL, "${TOOLCHAIN_PREFIX}install_name_tool", :)
AC_CHECK_PROGS(OBJCOPY, "${TOOLCHAIN_PREFIX}objcopy", :)
PATH=$_SAVE_PATH
])
AC_DEFUN([MOZ_CXX11],
[
dnl Updates to the test below should be duplicated further below for the
dnl cross-compiling case.
AC_LANG_CPLUSPLUS
if test "$GNU_CXX"; then
AC_CACHE_CHECK([whether 64-bits std::atomic requires -latomic],
ac_cv_needs_atomic,
dnl x86 with clang is a little peculiar. std::atomic does not require
dnl linking with libatomic, but using atomic intrinsics does, so we
dnl force the setting on for such systems.
if test "$CC_TYPE" = "clang" -a "$CPU_ARCH" = "x86" -a "$OS_ARCH" = "Linux"; then
ac_cv_needs_atomic=yes
else
AC_TRY_LINK(
[#include <cstdint>
#include <atomic>],
[ std::atomic<uint64_t> foo; foo = 1; ],
ac_cv_needs_atomic=no,
_SAVE_LIBS="$LIBS"
LIBS="$LIBS -latomic"
AC_TRY_LINK(
[#include <cstdint>
#include <atomic>],
[ std::atomic<uint64_t> foo; foo = 1; ],
ac_cv_needs_atomic=yes,
ac_cv_needs_atomic="do not know; assuming no")
LIBS="$_SAVE_LIBS"
)
fi
)
if test "$ac_cv_needs_atomic" = yes; then
MOZ_NEEDS_LIBATOMIC=1
else
MOZ_NEEDS_LIBATOMIC=
fi
AC_SUBST(MOZ_NEEDS_LIBATOMIC)
fi
AC_LANG_C
])