[PATCH] Reverse the order of OVERRIDES

[Chris Larson <kergoth@gmail.com>]

From: Chris Larson <chris_larson@mentor.com>

Given the current implementation of OVERRIDES in bitbake, the variable is
expected to contain elements in the order least specific to most specific,
however, our current usage of it does not match that.  As one example, "local"
is supposed to always be the most specific override, yet currently it's the
least specific.  As another example, currently the target architecture is seen
as more specific than the machine, which is also clearly wrong.

It becomes clear that a reversal of the current value will bring us to a more
sane behavior, and avoids the need for the dual overrides hack mentioned in
the comments, so clean those up as well.

This also introduces a MACHINE_OVERRIDES variable as a generic mechanism to
inject overrides elements which are more specific than the distro but less
specific than the machine, which is where things like MACHINE_CLASS or
SOC_FAMILY or the like would go.  This variable is *space* separated, to make
it easier and more convenient to assemble the variable incrementally, and it's
then translated to : separated when used in OVERRIDES.

Signed-off-by: Chris Larson <chris_larson@mentor.com>
---
 conf/bitbake.conf                             |   17 +++--------------
 conf/distro/include/arm-thumb.inc             |    6 +++---
 conf/distro/micro.conf                        |    6 +++---
 conf/distro/minimal.conf                      |    5 +++--
 conf/distro/shr.conf                          |    5 +++--
 conf/machine/fsg3be.conf                      |    2 +-
 conf/machine/kixrp435.conf                    |    2 +-
 conf/machine/nslu2be.conf                     |    2 +-
 conf/machine/nslu2le.conf                     |    2 +-
 recipes/binutils/binutils_csl-arm-20050416.bb |    2 +-
 recipes/binutils/binutils_csl-arm-20050603.bb |    2 +-
 recipes/eglibc/eglibc-package.bbclass         |    2 +-
 recipes/glibc/glibc-package.inc               |    2 +-
 recipes/prelink/prelink_20061027.bb           |    2 +-
 recipes/prelink/prelink_20071009.bb           |    2 +-
 recipes/prelink/prelink_20090925.bb           |    2 +-
 16 files changed, 26 insertions(+), 35 deletions(-)

diff --git a/conf/bitbake.conf b/conf/bitbake.conf
index 494e14e..c2359dc 100644
--- a/conf/bitbake.conf
+++ b/conf/bitbake.conf
@@ -675,20 +675,9 @@ BUILDCFG_NEEDEDVARS ?= "TARGET_ARCH TARGET_OS"
 
 # Overrides are processed left to right, so the ones that are named later take precedence.
 # You generally want them to go from least to most specific.
-# 
-# This means that an envionment variable named '<foo>_arm' overrides an
-# environment variable '<foo>' (when ${TARGET_ARCH} is arm).
-# an environment variable '<foo>_ramses' overrides '<foo>' but doesn't override
-# '<foo>_arm' when ${MACHINE} is 'ramses'. 
-# If you use combination ie '<foo>_arm_ramses', then '<foo>_arm_ramses' will override 
-# '<foo>_arm' and then '<foo>' will be overriden with that value from '<foo>_arm'.
-# And finally '<foo>_local' overrides anything, but with lowest priority.
-#
-# This works for  functions as well, they are really just environment variables.
-# Default OVERRIDES to make compilation fail fast in case of build system misconfiguration.
-OVERRIDES = "local:${MACHINE}:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
-# Alternative OVERRIDES definition without "fail fast", usually only for native building and Scratchbox toolchains.
-#OVERRIDES = "local:${MACHINE}:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:pn-${PN}"
+MACHINE_OVERRIDES ?= ""
+OVERRIDES = "pn-${PN}:fail-fast:build-${BUILD_OS}:${TARGET_ARCH}:${TARGET_OS}:\
+${DISTRO}:${@':'.join(d.getVar('MACHINE_OVERRIDES', True).split())}:${MACHINE}:local"
 
 ##################################################################
 # Include the rest of the config files.
diff --git a/conf/distro/include/arm-thumb.inc b/conf/distro/include/arm-thumb.inc
index 36edd4f..75ed978 100644
--- a/conf/distro/include/arm-thumb.inc
+++ b/conf/distro/include/arm-thumb.inc
@@ -16,9 +16,9 @@ THUMB_INTERWORK ?= "no"
 #    arm system and vice versa.  It is strongly recommended that DISTROs not
 #    turn this off - the actual cost is very small.
 
-OVERRIDE_THUMB = "${@['', ':thumb'][bb.data.getVar('ARM_INSTRUCTION_SET', d, 1) == 'thumb']}"
-OVERRIDE_INTERWORK = "${@['', ':thumb-interwork'][bb.data.getVar('THUMB_INTERWORK', d, 1) == 'yes']}"
-OVERRIDES_append_arm =. "${OVERRIDE_THUMB}${OVERRIDE_INTERWORK}"
+OVERRIDE_THUMB = "${@['', 'thumb:'][bb.data.getVar('ARM_INSTRUCTION_SET', d, 1) == 'thumb']}"
+OVERRIDE_INTERWORK = "${@['', 'thumb-interwork:'][bb.data.getVar('THUMB_INTERWORK', d, 1) == 'yes']}"
+OVERRIDES_prepend_arm =. "${OVERRIDE_THUMB}${OVERRIDE_INTERWORK}"
 
 #    Compiler and linker options for application code and kernel code.  These
 #    options ensure that the compiler has the correct settings for the selected
diff --git a/conf/distro/micro.conf b/conf/distro/micro.conf
index 6d396b3..19b5e62 100644
--- a/conf/distro/micro.conf
+++ b/conf/distro/micro.conf
@@ -69,10 +69,10 @@ require conf/distro/include/sane-toolchain.inc
 require conf/distro/include/arm-thumb.inc
 
 #############################################################################
-# OVERRIDES adjusted from bitbake.conf to feature the MACHINE_CLASS
+# Ensure MACHINE_CLASS is in OVERRIDES
 #############################################################################
-OVERRIDES = "local:${MACHINE}:${MACHINE_CLASS}:${DISTRO}:${TARGET_OS}:\
-${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
+MACHINE_CLASS ?= ""
+MACHINE_OVERRIDES += "${MACHINE_CLASS}"
 
 #############################################################################
 # PREFERRED VERSIONS
diff --git a/conf/distro/minimal.conf b/conf/distro/minimal.conf
index 376ffde..0d32cfe 100644
--- a/conf/distro/minimal.conf
+++ b/conf/distro/minimal.conf
@@ -81,9 +81,10 @@ KERNEL = "kernel26"
 MACHINE_KERNEL_VERSION = "2.6"
 
 #############################################################################
-# OVERWRITES adjusted from bitbake.conf to feature the MACHINE_CLASS
+# Ensure MACHINE_CLASS is in OVERRIDES
 #############################################################################
-OVERRIDES = "local:${MACHINE}:${MACHINE_CLASS}:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
+MACHINE_CLASS ?= ""
+MACHINE_OVERRIDES += "${MACHINE_CLASS}"
 
 #############################################################################
 # TOOLCHAIN
diff --git a/conf/distro/shr.conf b/conf/distro/shr.conf
index ade8cba..74e3fe9 100644
--- a/conf/distro/shr.conf
+++ b/conf/distro/shr.conf
@@ -151,9 +151,10 @@ KERNEL = "kernel26"
 MACHINE_KERNEL_VERSION = "2.6"
 
 #############################################################################
-# OVERWRITES adjusted from bitbake.conf to feature the MACHINE_CLASS
+# Ensure MACHINE_CLASS is in OVERRIDES
 #############################################################################
-OVERRIDES = "local:${MACHINE}:${MACHINE_CLASS}:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
+MACHINE_CLASS ?= ""
+MACHINE_OVERRIDES += "${MACHINE_CLASS}"
 
 #############################################################################
 # TOOLCHAIN
diff --git a/conf/machine/fsg3be.conf b/conf/machine/fsg3be.conf
index a2ca95b..c5ddc25 100644
--- a/conf/machine/fsg3be.conf
+++ b/conf/machine/fsg3be.conf
@@ -8,7 +8,7 @@ PACKAGE_EXTRA_ARCHS = "ixp4xxbe"
 
 MACHINE_ARCH = "ixp4xxbe"
 
-OVERRIDES = "local:${MACHINE}:ixp4xxbe:ixp4xx:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
+MACHINE_OVERRIDES += "ixp4xx ixp4xxbe"
 
 # Match the vendor's latest kernel
 PREFERRED_PROVIDER_virtual/kernel ?= "fsg3-kernel"
diff --git a/conf/machine/kixrp435.conf b/conf/machine/kixrp435.conf
index 8259127..b4a2fa6 100644
--- a/conf/machine/kixrp435.conf
+++ b/conf/machine/kixrp435.conf
@@ -7,7 +7,7 @@ TARGET_ARCH = "arm"
 # Note: armv4 armv4t armv5te will be added by tune-xscale.inc automatically.
 PACKAGE_EXTRA_ARCHS = "armv5e ixp4xxle"
 
-OVERRIDES = "local:${MACHINE}:nslu2:ixp4xx:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
+MACHINE_OVERRIDES += "nslu2 ixp4xx"
 
 PREFERRED_PROVIDER_virtual/kernel = "linux"
 PREFERRED_VERSION_linux = "2.6.30"
diff --git a/conf/machine/nslu2be.conf b/conf/machine/nslu2be.conf
index 9bc92f1..88e6ed2 100644
--- a/conf/machine/nslu2be.conf
+++ b/conf/machine/nslu2be.conf
@@ -7,7 +7,7 @@ TARGET_ARCH = "armeb"
 # Note: armv4b armv4tb armv5teb will be added by tune-xscale.inc automatically.
 PACKAGE_EXTRA_ARCHS = "armv5eb ixp4xxbe"
 
-OVERRIDES = "local:${MACHINE}:nslu2:ixp4xx:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
+MACHINE_OVERRIDES += "nslu2 ixp4xx"
 
 ROOT_FLASH_SIZE ?= "6"
 
diff --git a/conf/machine/nslu2le.conf b/conf/machine/nslu2le.conf
index 62e47cb..edd0d94 100644
--- a/conf/machine/nslu2le.conf
+++ b/conf/machine/nslu2le.conf
@@ -7,7 +7,7 @@ TARGET_ARCH = "arm"
 # Note: armv4 armv4t armv5te will be added by tune-xscale.inc automatically.
 PACKAGE_EXTRA_ARCHS = "armv5e ixp4xxle"
 
-OVERRIDES = "local:${MACHINE}:nslu2:ixp4xx:${DISTRO}:${TARGET_OS}:${TARGET_ARCH}:build-${BUILD_OS}:fail-fast:pn-${PN}"
+MACHINE_OVERRIDES += "nslu2 ixp4xx"
 
 ROOT_FLASH_SIZE ?= "6"
 
diff --git a/recipes/binutils/binutils_csl-arm-20050416.bb b/recipes/binutils/binutils_csl-arm-20050416.bb
index ad45438..71803d1 100644
--- a/recipes/binutils/binutils_csl-arm-20050416.bb
+++ b/recipes/binutils/binutils_csl-arm-20050416.bb
@@ -7,7 +7,7 @@ LICENSE = "GPL"
 FILESDIR = "${@os.path.dirname(bb.data.getVar('FILE',d,1))}/binutils-cvs"
 PV = "2.15.99+csl-arm+cvs20050416"
 PR = "r3"
-OVERRIDES_append = ":${TARGET_ARCH}-${TARGET_OS}"
+OVERRIDES_prepend = "${TARGET_ARCH}-${TARGET_OS}:"
 DEFAULT_PREFERENCE = "-1"
 DEFAULT_PREFERENCE_arm-linux = "-1"
 DEFAULT_PREFERENCE_arm-linuxeabi = "-1"
diff --git a/recipes/binutils/binutils_csl-arm-20050603.bb b/recipes/binutils/binutils_csl-arm-20050603.bb
index 595cb98..50e8677 100644
--- a/recipes/binutils/binutils_csl-arm-20050603.bb
+++ b/recipes/binutils/binutils_csl-arm-20050603.bb
@@ -7,7 +7,7 @@ LICENSE = "GPL"
 FILESDIR = "${@os.path.dirname(bb.data.getVar('FILE',d,1))}/binutils-cvs"
 PV = "2.15.99+csl-arm+cvs20050603"
 PR = "r3"
-OVERRIDES_append = ":${TARGET_ARCH}-${TARGET_OS}"
+OVERRIDES_prepend = "${TARGET_ARCH}-${TARGET_OS}:"
 DEFAULT_PREFERENCE = "-1"
 #DEFAULT_PREFERENCE_arm-linux = "1"
 #DEFAULT_PREFERENCE_arm-linuxeabi = "1"
diff --git a/recipes/eglibc/eglibc-package.bbclass b/recipes/eglibc/eglibc-package.bbclass
index dbca1ab..c802bd5 100644
--- a/recipes/eglibc/eglibc-package.bbclass
+++ b/recipes/eglibc/eglibc-package.bbclass
@@ -116,7 +116,7 @@ def get_eglibc_fpu_setting(bb, d):
 EXTRA_OECONF += "${@get_eglibc_fpu_setting(bb, d)}"
 EXTRA_OEMAKE += "rootsbindir=${base_sbindir}"
 
-OVERRIDES_append = ":${TARGET_ARCH}-${TARGET_OS}"
+OVERRIDES_prepend = "${TARGET_ARCH}-${TARGET_OS}:"
 
 do_configure_prepend() {
         sed -e "s#@BASH@#/bin/sh#" -i ${S}/elf/ldd.bash.in
diff --git a/recipes/glibc/glibc-package.inc b/recipes/glibc/glibc-package.inc
index 0b263bb..8cd8564 100644
--- a/recipes/glibc/glibc-package.inc
+++ b/recipes/glibc/glibc-package.inc
@@ -44,7 +44,7 @@ def get_glibc_fpu_setting(bb, d):
 EXTRA_OECONF += "${@get_glibc_fpu_setting(bb, d)}"
 EXTRA_OEMAKE += "rootsbindir=${base_sbindir}"
 
-OVERRIDES_append = ":${TARGET_ARCH}-${TARGET_OS}"
+OVERRIDES_prepend = "${TARGET_ARCH}-${TARGET_OS}:"
 
 do_install() {
 	oe_runmake install_root=${D} install
diff --git a/recipes/prelink/prelink_20061027.bb b/recipes/prelink/prelink_20061027.bb
index ad2faf5..552117b 100644
--- a/recipes/prelink/prelink_20061027.bb
+++ b/recipes/prelink/prelink_20061027.bb
@@ -12,7 +12,7 @@ SRC_URI = "${DEBIAN_MIRROR}/main/p/prelink/prelink_0.0.${PV}.orig.tar.gz \
            file://prelink.default"
 
 TARGET_OS_ORIG := "${TARGET_OS}"
-OVERRIDES_append = ":${TARGET_OS_ORIG}"
+OVERRIDES_prepend = "${TARGET_OS_ORIG}:"
 SRC_URI_append_linux-gnueabi = " file://arm_eabi.patch"
 
 S = "${WORKDIR}/prelink-0.0.${PV}"
diff --git a/recipes/prelink/prelink_20071009.bb b/recipes/prelink/prelink_20071009.bb
index faf930c..e2ab3fb 100644
--- a/recipes/prelink/prelink_20071009.bb
+++ b/recipes/prelink/prelink_20071009.bb
@@ -12,7 +12,7 @@ SRC_URI = "${DEBIAN_MIRROR}/main/p/prelink/prelink_0.0.${PV}.orig.tar.gz \
            file://prelink.default"
 
 TARGET_OS_ORIG := "${TARGET_OS}"
-OVERRIDES_append = ":${TARGET_OS_ORIG}"
+OVERRIDES_prepend = "${TARGET_OS_ORIG}:"
 SRC_URI_append_linux-gnueabi = " file://arm_eabi.patch"
 
 S = "${WORKDIR}/prelink-0.0.${PV}"
diff --git a/recipes/prelink/prelink_20090925.bb b/recipes/prelink/prelink_20090925.bb
index 4c83402..5b247b6 100644
--- a/recipes/prelink/prelink_20090925.bb
+++ b/recipes/prelink/prelink_20090925.bb
@@ -12,7 +12,7 @@ SRC_URI = "${DEBIAN_MIRROR}/main/p/prelink/prelink_0.0.${PV}.orig.tar.gz \
            file://prelink.default"
 
 #TARGET_OS_ORIG := "${TARGET_OS}"
-#OVERRIDES_append = ":${TARGET_OS_ORIG}"
+#OVERRIDES_prepend = "${TARGET_OS_ORIG}:"
 #SRC_URI_append_linux-gnueabi = " file://arm_eabi.patch"
 
 S = "${WORKDIR}/prelink-0.0.${PV}"
-- 
1.7.2.3