[Buildroot] [PATCH v3 1/2] erlang: use erlang's native atomic ops
Frank Hunleth
fhunleth at troodon-software.com
Sun Feb 21 19:17:25 UTC 2016
Now that we're using Erlang 18, the preferred atomic ops implementation
for Erlang is its own built-in implementation, so use it. It is still
possible to use libatomic_ops if the native implementation does not
work. BR2_PACKAGE_ERLANG_ARCH_SUPPORTS is added now that
BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS is no longer appropriate for
checking whether Erlang can be built for a platform.
This fixes an autobuilder failure when using libatomic_ops on aarch64.
Erlang's native atomic ops implementation works on this platform.
Fixes:
http://autobuild.buildroot.net/results/0cd/0cd22eb74fa29e5a85bf897762e16ab3daf33962/
Signed-off-by: Frank Hunleth <fhunleth at troodon-software.com>
---
Changes v2->v3:
- Move LIBS=-latomic_ops change to a separate commit
- Rebased to pull in BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS to
BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS change
- Note that the BR2_PACKAGE_ERLANG_ARCH_SUPPORTS caused me to
move the missing dependencies comment from the beginning of
the file down to the end.
- Made libatomic_ops a selection for now per comment from
Romain Naour. While Erlang supports a lot of options,
libatomic_ops was the only alternative in the choices.
Even then, it may not be used that often since the Erlang
native support covers most platforms.
Changes v1->v2:
- Add BR2_PACKAGE_ERLANG_ARCH_SUPPORTS and related changes
(Thanks to Thomas)
- Atomic ops selection is a choice now due to the potential for
more than two options based on the Erlang documentation.
- Line wrapping updates
- Added note on Erlang choosing native atomic ops even if
libatomic_ops is present.
- Removed LIBS=-latomic_ops. The ./configure test for it still
worked, and Erlang linked to it without errors.
package/erlang/Config.in | 41 +++++++++++++++++++++++++++++++++++------
package/erlang/erlang.mk | 4 ++++
2 files changed, 39 insertions(+), 6 deletions(-)
diff --git a/package/erlang/Config.in b/package/erlang/Config.in
index 5fa2028..d17fb7a 100644
--- a/package/erlang/Config.in
+++ b/package/erlang/Config.in
@@ -1,14 +1,30 @@
-comment "erlang needs a toolchain w/ dynamic library"
- depends on BR2_USE_MMU # fork()
- depends on BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS
- depends on BR2_STATIC_LIBS
+# Erlang requires platform support for atomic operations. See the
+# HOWTO/INSTALL.md file for the full description. A summary of the
+# options is as follows:
+#
+# 1. Erlang's atomic operations on 32/64-bit x86, 32/64-bit
+# SPARC V9, 32-bit PowerPC, or 32-bit Tile. The INSTALL.md
+# omits 32/64-bit ARM support, but those are supported as well.
+# 2. The API provided by Windows (N/A for Buildroot)
+# 3. Native atomic operations provided by the '__atomic_*' builtins
+# with gcc 4.7 or later.
+# 4. libatomic_ops
+# 5. The availability of __sync_*() operations. Based on
+# http://autobuild.buildroot.org/results/209/2090874eee165af3349cf2d597657fc1b4ca1012/build-end.log,
+# it needs the 4-byte and 8-byte versions.
+#
+# Cases 3 and 5 do not appear to work on configurations that are not
+# included in 1 and 4 due to compiler errors.
+config BR2_PACKAGE_ERLANG_ARCH_SUPPORTS
+ bool
+ default y if BR2_i386 || BR2_x86_64 || BR2_powerpc || BR2_sparc_v9 || BR2_arm || BR2_aarch64 # case (1)
+ default y if BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS # case (4)
config BR2_PACKAGE_ERLANG
bool "erlang"
depends on BR2_USE_MMU # fork()
depends on !BR2_STATIC_LIBS
- depends on BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS
- select BR2_PACKAGE_LIBATOMIC_OPS
+ depends on BR2_PACKAGE_ERLANG_ARCH_SUPPORTS
help
Erlang is a programming language used to build massively scalable
soft real-time systems with requirements on high availability.
@@ -20,6 +36,14 @@ config BR2_PACKAGE_ERLANG
if BR2_PACKAGE_ERLANG
+config BR2_PACKAGE_ERLANG_LIBATOMIC_OPS
+ bool "libatomic_ops"
+ depends on BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS
+ depends on !BR2_aarch64 # causes build failures
+ select BR2_PACKAGE_LIBATOMIC_OPS
+ help
+ Use libatomic_ops instead of Erlang's native atomic ops support.
+
config BR2_PACKAGE_ERLANG_SMP
bool "enable SMP support"
help
@@ -38,3 +62,8 @@ config BR2_PACKAGE_ERLANG_MEGACO
enable it.
endif # BR2_PACKAGE_ERLANG
+
+comment "erlang needs a toolchain w/ dynamic library, atomic_ops"
+ depends on BR2_USE_MMU # fork()
+ depends on BR2_STATIC_LIBS || !BR2_PACKAGE_ERLANG_ARCH_SUPPORTS
+
diff --git a/package/erlang/erlang.mk b/package/erlang/erlang.mk
index 638d2c2..8257ab4 100644
--- a/package/erlang/erlang.mk
+++ b/package/erlang/erlang.mk
@@ -30,8 +30,12 @@ ERLANG_CONF_ENV += erl_xcomp_sysroot=$(STAGING_DIR)
ERLANG_CONF_OPTS = --without-javac
+# Erlang uses its own native atomic ops implementation if support is
+# available. Override this if the user wants libatomic_ops.
+ifeq ($(BR2_PACKAGE_ERLANG_LIBATOMIC_OPS),y)
ERLANG_DEPENDENCIES += libatomic_ops
ERLANG_CONF_OPTS += --with-libatomic_ops=$(STAGING_DIR)/usr LIBS=-latomic_ops
+endif
# erlang uses openssl for all things crypto. Since the host tools (such as
# rebar) uses crypto, we need to build host-erlang with support for openssl.
--
2.5.0
More information about the buildroot
mailing list