diff mbox

[GCC/ARM,2/2,ping] Allow combination of aprofile and rmprofile multilibs

Message ID 49f38170-be52-c9de-2d6f-f2f26e3362a7@foss.arm.com
State New
Headers show

Commit Message

Thomas Preudhomme Oct. 24, 2016, 8:07 a.m. UTC 
Ping?

Best regards,

Thomas

On 13/10/16 16:35, Thomas Preudhomme wrote:
> Hi ARM maintainers,
>
> This patchset aims at adding multilib support for R and M profile ARM
> architectures and allowing it to be built alongside multilib for A profile ARM
> architectures. This specific patch is concerned with the latter. The patch works
> by moving the bits shared by both aprofile and rmprofile multilib build
> (variable initilization as well as ISA and float ABI to build multilib for) to a
> new t-multilib file. Then, based on which profile was requested in
> --with-multilib-list option, that files includes t-aprofile and/or t-rmprofile
> where the architecture and FPU to build the multilib for are specified.
>
> Unfortunately the duplication of CPU to A profile architectures could not be
> avoided because substitution due to MULTILIB_MATCHES are not transitive.
> Therefore, mapping armv7-a to armv7 for rmprofile multilib build does not have
> the expected effect. Two patches were written to allow this using 2 different
> approaches but I decided against it because this is not the right solution IMO.
> See caveats below for what I believe is the correct approach.
>
>
> *** combined build caveats ***
>
> As the documentation in this patch warns, there is a few caveats to using a
> combined multilib build due to the way the multilib framework works.
>
> 1) For instance, when using only rmprofile the combination of options -mthumb
> -march=armv7 -mfpu=neon the thumb/-march=armv7 multilib but in a combined
> multilib build the default multilib would be used. This is because in the
> rmprofile build -mfpu=neon is not specified in MULTILIB_OPTION and thus the
> option is ignored when considering MULTILIB_REQUIRED entries.
>
> 2) Another issue is the fact that aprofile and rmprofile multilib build have
> some conflicting requirements in terms of how to map options for which no
> multilib is built to another option. (i) A first example of this is the
> difference of CPU to architecture mapping mentionned above: rmprofile multilib
> build needs A profile CPUs and architectures to be mapped down to ARMv7 so that
> one of the v7-ar multilib gets chosen in such a case but aprofile needs A
> profile architectures to stand on their own because multilibs are built for
> several architectures.
>
> (ii) Another example of this is that in aprofile multilib build no multilib is
> built with -mfpu=fpv5-d16 but some multilibs are built with -mfpu=fpv4-d16.
> Therefore, aprofile defines a match rule to map fpv5-d16 onto fpv4-d16. However,
> rmprofile multilib profile *does* build some multilibs with -mfpu=fpv5-d16. This
> has the consequence that when building for -mthumb -march=armv7e-m
> -mfpu=fpv5-d16 -mfloat-abi=hard the default multilib is chosen because this is
> rewritten into -mthumb -march=armv7e-m -mfpu=fpv5-d16 -mfloat-abi=hard and there
> is no multilib for that.
>
> Both of these issues could be handled by using MULTILIB_REUSE instead of
> MULTILIB_MATCHES but this would require a large set of rules. I believe instead
> the right approach is to create a new mechanism to inform GCC on how options can
> be down mapped _when no multilib can be found_ which would require a smaller set
> of rules and would make it explicit that the options are not equivalent. A patch
> will be posted to this effect at a later time.
>
> ChangeLog entry is as follows:
>
>
> *** gcc/ChangeLog ***
>
> 2016-10-03  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>
>         * config.gcc: Allow combinations of aprofile and rmprofile values for
>         --with-multilib-list.
>         * config/arm/t-multilib: New file.
>         * config/arm/t-aprofile: Remove initialization of MULTILIB_*
>         variables.  Remove setting of ISA and floating-point ABI in
>         MULTILIB_OPTIONS and MULTILIB_DIRNAMES.  Set architecture and FPU in
>         MULTI_ARCH_OPTS_A and MULTI_ARCH_DIRS_A rather than MULTILIB_OPTIONS
>         and MULTILIB_DIRNAMES respectively.  Add comment to introduce all
>         matches.  Add architecture matches for marvel-pj4 and generic-armv7-a
>         CPU options.
>         * config/arm/t-rmprofile: Likewise except for the matches changes.
>         * doc/install.texi (--with-multilib-list): Document the combination of
>         aprofile and rmprofile values and warn about pitfalls in doing that.
>
>
> Testing:
>
> * "tree install/lib/gcc/arm-none-eabi/7.0.0" is the same before and after the
> patchset for both aprofile and rmprofile
> * "tree install/lib/gcc/arm-none-eabi/7.0.0" is the same for aprofile,rmprofile
> and rmprofile,aprofile
> * default spec (gcc -dumpspecs) is the same for aprofile,rmprofile and
> rmprofile,aprofile
>
> * Difference in --print-multi-directory between aprofile or rmprofile and
> aprofile,rmprofile for all combination of ISA (ARM/Thumb), architecture, CPU,
> FPU and float ABI is as expected (best multilib for the combination is chosen),
> modulo the caveat mentionned above and the new marvel-pj4 and generic-armv7-a
> CPU to architecture mapping.
>
>
> Is this ok for master?
>
> Best regards,
>
> Thomas

Comments

Thomas Preudhomme Nov. 2, 2016, 10:05 a.m. UTC | #1 
Ping?

Best regards,

Thomas

On 24/10/16 09:07, Thomas Preudhomme wrote:
> Ping?
>
> Best regards,
>
> Thomas
>
> On 13/10/16 16:35, Thomas Preudhomme wrote:
>> Hi ARM maintainers,
>>
>> This patchset aims at adding multilib support for R and M profile ARM
>> architectures and allowing it to be built alongside multilib for A profile ARM
>> architectures. This specific patch is concerned with the latter. The patch works
>> by moving the bits shared by both aprofile and rmprofile multilib build
>> (variable initilization as well as ISA and float ABI to build multilib for) to a
>> new t-multilib file. Then, based on which profile was requested in
>> --with-multilib-list option, that files includes t-aprofile and/or t-rmprofile
>> where the architecture and FPU to build the multilib for are specified.
>>
>> Unfortunately the duplication of CPU to A profile architectures could not be
>> avoided because substitution due to MULTILIB_MATCHES are not transitive.
>> Therefore, mapping armv7-a to armv7 for rmprofile multilib build does not have
>> the expected effect. Two patches were written to allow this using 2 different
>> approaches but I decided against it because this is not the right solution IMO.
>> See caveats below for what I believe is the correct approach.
>>
>>
>> *** combined build caveats ***
>>
>> As the documentation in this patch warns, there is a few caveats to using a
>> combined multilib build due to the way the multilib framework works.
>>
>> 1) For instance, when using only rmprofile the combination of options -mthumb
>> -march=armv7 -mfpu=neon the thumb/-march=armv7 multilib but in a combined
>> multilib build the default multilib would be used. This is because in the
>> rmprofile build -mfpu=neon is not specified in MULTILIB_OPTION and thus the
>> option is ignored when considering MULTILIB_REQUIRED entries.
>>
>> 2) Another issue is the fact that aprofile and rmprofile multilib build have
>> some conflicting requirements in terms of how to map options for which no
>> multilib is built to another option. (i) A first example of this is the
>> difference of CPU to architecture mapping mentionned above: rmprofile multilib
>> build needs A profile CPUs and architectures to be mapped down to ARMv7 so that
>> one of the v7-ar multilib gets chosen in such a case but aprofile needs A
>> profile architectures to stand on their own because multilibs are built for
>> several architectures.
>>
>> (ii) Another example of this is that in aprofile multilib build no multilib is
>> built with -mfpu=fpv5-d16 but some multilibs are built with -mfpu=fpv4-d16.
>> Therefore, aprofile defines a match rule to map fpv5-d16 onto fpv4-d16. However,
>> rmprofile multilib profile *does* build some multilibs with -mfpu=fpv5-d16. This
>> has the consequence that when building for -mthumb -march=armv7e-m
>> -mfpu=fpv5-d16 -mfloat-abi=hard the default multilib is chosen because this is
>> rewritten into -mthumb -march=armv7e-m -mfpu=fpv5-d16 -mfloat-abi=hard and there
>> is no multilib for that.
>>
>> Both of these issues could be handled by using MULTILIB_REUSE instead of
>> MULTILIB_MATCHES but this would require a large set of rules. I believe instead
>> the right approach is to create a new mechanism to inform GCC on how options can
>> be down mapped _when no multilib can be found_ which would require a smaller set
>> of rules and would make it explicit that the options are not equivalent. A patch
>> will be posted to this effect at a later time.
>>
>> ChangeLog entry is as follows:
>>
>>
>> *** gcc/ChangeLog ***
>>
>> 2016-10-03  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>>
>>         * config.gcc: Allow combinations of aprofile and rmprofile values for
>>         --with-multilib-list.
>>         * config/arm/t-multilib: New file.
>>         * config/arm/t-aprofile: Remove initialization of MULTILIB_*
>>         variables.  Remove setting of ISA and floating-point ABI in
>>         MULTILIB_OPTIONS and MULTILIB_DIRNAMES.  Set architecture and FPU in
>>         MULTI_ARCH_OPTS_A and MULTI_ARCH_DIRS_A rather than MULTILIB_OPTIONS
>>         and MULTILIB_DIRNAMES respectively.  Add comment to introduce all
>>         matches.  Add architecture matches for marvel-pj4 and generic-armv7-a
>>         CPU options.
>>         * config/arm/t-rmprofile: Likewise except for the matches changes.
>>         * doc/install.texi (--with-multilib-list): Document the combination of
>>         aprofile and rmprofile values and warn about pitfalls in doing that.
>>
>>
>> Testing:
>>
>> * "tree install/lib/gcc/arm-none-eabi/7.0.0" is the same before and after the
>> patchset for both aprofile and rmprofile
>> * "tree install/lib/gcc/arm-none-eabi/7.0.0" is the same for aprofile,rmprofile
>> and rmprofile,aprofile
>> * default spec (gcc -dumpspecs) is the same for aprofile,rmprofile and
>> rmprofile,aprofile
>>
>> * Difference in --print-multi-directory between aprofile or rmprofile and
>> aprofile,rmprofile for all combination of ISA (ARM/Thumb), architecture, CPU,
>> FPU and float ABI is as expected (best multilib for the combination is chosen),
>> modulo the caveat mentionned above and the new marvel-pj4 and generic-armv7-a
>> CPU to architecture mapping.
>>
>>
>> Is this ok for master?
>>
>> Best regards,
>>
>> Thomas
diff mbox

Patch

diff --git a/gcc/config.gcc b/gcc/config.gcc
index bfd1127d6e8e647ca8c3a57dd2d58b586dffe4a5..d7508e89de0e1d7a3027da0b04e4fa36c1e95fd0 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -3710,34 +3710,18 @@  case "${target}" in
 		# Add extra multilibs
 		if test "x$with_multilib_list" != x; then
 			arm_multilibs=`echo $with_multilib_list | sed -e 's/,/ /g'`
-			case ${arm_multilibs} in
-			aprofile)
-				# Note that arm/t-aprofile is a
-				# stand-alone make file fragment to be
-				# used only with itself.  We do not
-				# specifically use the
-				# TM_MULTILIB_OPTION framework because
-				# this shorthand is more
-				# pragmatic.
-				tmake_profile_file="arm/t-aprofile"
-				;;
-			rmprofile)
-				# Note that arm/t-rmprofile is a
-				# stand-alone make file fragment to be
-				# used only with itself.  We do not
-				# specifically use the
-				# TM_MULTILIB_OPTION framework because
-				# this shorthand is more
-				# pragmatic.
-				tmake_profile_file="arm/t-rmprofile"
-				;;
-			default)
-				;;
-			*)
-				echo "Error: --with-multilib-list=${with_multilib_list} not supported." 1>&2
-				exit 1
-				;;
-			esac
+			if test "x${arm_multilibs}" != xdefault ; then
+				for arm_multilib in ${arm_multilibs}; do
+					case ${arm_multilib} in
+					aprofile|rmprofile)
+						tmake_profile_file="arm/t-multilib"
+						;;
+					*)
+						echo "Error: --with-multilib-list=${with_multilib_list} not supported." 1>&2
+						exit 1
+						;;
+					esac
+				done
 
 			if test "x${tmake_profile_file}" != x ; then
 				# arm/t-aprofile and arm/t-rmprofile are only
diff --git a/gcc/config/arm/t-aprofile b/gcc/config/arm/t-aprofile
index 90305e1206e3964e08a673e385d3198747bdffa1..2cbd8e3c8e8bcd4bed6368bfea83ece953c8dbb4 100644
--- a/gcc/config/arm/t-aprofile
+++ b/gcc/config/arm/t-aprofile
@@ -24,30 +24,13 @@ 
 # have their default values during the configure step.  We enforce
 # this during the top-level configury.
 
-MULTILIB_OPTIONS     =
-MULTILIB_DIRNAMES    =
-MULTILIB_EXCEPTIONS  =
-MULTILIB_MATCHES     =
-MULTILIB_REUSE	     =
+# Arch and FPU variants to build libraries with
 
-# We have the following hierachy:
-#   ISA: A32 (.) or T32 (thumb)
-#   Architecture: ARMv7-A (v7-a), ARMv7VE (v7ve), or ARMv8-A (v8-a).
-#   FPU: VFPv3-D16 (fpv3), NEONv1 (simdv1), VFPv4-D16 (fpv4),
-#        NEON-VFPV4 (simdvfpv4), NEON for ARMv8 (simdv8), or None (.).
-#   Float-abi: Soft (.), softfp (softfp), or hard (hardfp).
+MULTI_ARCH_OPTS_A       = march=armv7-a/march=armv7ve/march=armv8-a
+MULTI_ARCH_DIRS_A       = v7-a v7ve v8-a
 
-MULTILIB_OPTIONS       += mthumb
-MULTILIB_DIRNAMES      += thumb
-
-MULTILIB_OPTIONS       += march=armv7-a/march=armv7ve/march=armv8-a
-MULTILIB_DIRNAMES      += v7-a v7ve v8-a
-
-MULTILIB_OPTIONS       += mfpu=vfpv3-d16/mfpu=neon/mfpu=vfpv4-d16/mfpu=neon-vfpv4/mfpu=neon-fp-armv8
-MULTILIB_DIRNAMES      += fpv3 simdv1 fpv4 simdvfpv4 simdv8
-
-MULTILIB_OPTIONS       += mfloat-abi=softfp/mfloat-abi=hard
-MULTILIB_DIRNAMES      += softfp hard
+MULTI_FPU_OPTS_A        = mfpu=vfpv3-d16/mfpu=neon/mfpu=vfpv4-d16/mfpu=neon-vfpv4/mfpu=neon-fp-armv8
+MULTI_FPU_DIRS_A        = fpv3 simdv1 fpv4 simdvfpv4 simdv8
 
 
 # Option combinations to build library with
@@ -71,7 +54,11 @@  MULTILIB_REQUIRED      += *march=armv8-a
 MULTILIB_REQUIRED      += *march=armv8-a/mfpu=neon-fp-armv8/mfloat-abi=*
 
 
+# Matches
+
 # CPU Matches
+MULTILIB_MATCHES       += march?armv7-a=mcpu?marvell-pj4
+MULTILIB_MATCHES       += march?armv7-a=mcpu?generic-armv7-a
 MULTILIB_MATCHES       += march?armv7-a=mcpu?cortex-a8
 MULTILIB_MATCHES       += march?armv7-a=mcpu?cortex-a9
 MULTILIB_MATCHES       += march?armv7-a=mcpu?cortex-a5
diff --git a/gcc/config/arm/t-multilib b/gcc/config/arm/t-multilib
new file mode 100644
index 0000000000000000000000000000000000000000..642e731765534904b752d7e15fb6b68a3db2708e
--- /dev/null
+++ b/gcc/config/arm/t-multilib
@@ -0,0 +1,69 @@ 
+# Copyright (C) 2016 Free Software Foundation, Inc.
+#
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GCC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# This is a target makefile fragment that attempts to get
+# multilibs built for the range of CPU's, FPU's and ABI's that
+# are relevant for the ARM architecture.  It should not be used in
+# conjunction with another make file fragment and assumes --with-arch,
+# --with-cpu, --with-fpu, --with-float, --with-mode have their default
+# values during the configure step.  We enforce this during the
+# top-level configury.
+
+MULTILIB_OPTIONS     =
+MULTILIB_DIRNAMES    =
+MULTILIB_EXCEPTIONS  =
+MULTILIB_MATCHES     =
+MULTILIB_REUSE	     =
+
+comma := ,
+tm_multilib_list := $(subst $(comma), ,$(TM_MULTILIB_CONFIG))
+
+HAS_APROFILE := $(filter aprofile,$(tm_multilib_list))
+HAS_RMPROFILE := $(filter rmprofile,$(tm_multilib_list))
+
+ifneq (,$(HAS_APROFILE))
+include $(srcdir)/config/arm/t-aprofile
+endif
+ifneq (,$(HAS_RMPROFILE))
+include $(srcdir)/config/arm/t-rmprofile
+endif
+SEP := $(and $(HAS_APROFILE),$(HAS_RMPROFILE),/)
+
+
+# We have the following hierachy:
+#   ISA: A32 (.) or T16/T32 (thumb)
+#   Architecture: ARMv6-M (v6-m), ARMv7-M (v7-m), ARMv7E-M (v7e-m),
+#                 ARMv7 (v7-ar), ARMv7-A (v7-a), ARMv7VE (v7ve),
+#                 ARMv8-M Baseline (v8-m.base), ARMv8-M Mainline (v8-m.main)
+#                 or ARMv8-A (v8-a).
+#   FPU: VFPv3-D16 (fpv3), NEONv1 (simdv1), FPV4-SP-D16 (fpv4-sp),
+#        VFPv4-D16 (fpv4), NEON-VFPV4 (simdvfpv4), FPV5-SP-D16 (fpv5-sp),
+#        VFPv5-D16 (fpv5), NEON for ARMv8 (simdv8), or None (.).
+#   Float-abi: Soft (.), softfp (softfp), or hard (hard).
+
+MULTILIB_OPTIONS       += mthumb
+MULTILIB_DIRNAMES      += thumb
+
+MULTILIB_OPTIONS       += $(MULTI_ARCH_OPTS_A)$(SEP)$(MULTI_ARCH_OPTS_RM)
+MULTILIB_DIRNAMES      += $(MULTI_ARCH_DIRS_A) $(MULTI_ARCH_DIRS_RM)
+
+MULTILIB_OPTIONS       += $(MULTI_FPU_OPTS_A)$(SEP)$(MULTI_FPU_OPTS_RM)
+MULTILIB_DIRNAMES      += $(MULTI_FPU_DIRS_A) $(MULTI_FPU_DIRS_RM)
+
+MULTILIB_OPTIONS       += mfloat-abi=softfp/mfloat-abi=hard
+MULTILIB_DIRNAMES      += softfp hard
diff --git a/gcc/config/arm/t-rmprofile b/gcc/config/arm/t-rmprofile
index c195a6590c2f8e1753a9f2498583f5be89df7d1e..ea6054dfd58be63426fc77e3a00a25fde96a8583 100644
--- a/gcc/config/arm/t-rmprofile
+++ b/gcc/config/arm/t-rmprofile
@@ -24,33 +24,14 @@ 
 # values during the configure step.  We enforce this during the
 # top-level configury.
 
-MULTILIB_OPTIONS     =
-MULTILIB_DIRNAMES    =
-MULTILIB_EXCEPTIONS  =
-MULTILIB_MATCHES     =
-MULTILIB_REUSE       =
 
-# We have the following hierachy:
-#   ISA: A32 (.) or T16/T32 (thumb).
-#   Architecture: ARMv6S-M (v6-m), ARMv7-M (v7-m), ARMv7E-M (v7e-m),
-#                 ARMv8-M Baseline (v8-m.base) or ARMv8-M Mainline (v8-m.main).
-#   FPU: VFPv3-D16 (fpv3), FPV4-SP-D16 (fpv4-sp), FPV5-SP-D16 (fpv5-sp),
-#        VFPv5-D16 (fpv5), or None (.).
-#   Float-abi: Soft (.), softfp (softfp), or hard (hardfp).
+# Arch and FPU variants to build libraries with
 
-# Options to build libraries with
+MULTI_ARCH_OPTS_RM      = march=armv6s-m/march=armv7-m/march=armv7e-m/march=armv7/march=armv8-m.base/march=armv8-m.main
+MULTI_ARCH_DIRS_RM      = v6-m v7-m v7e-m v7-ar v8-m.base v8-m.main
 
-MULTILIB_OPTIONS       += mthumb
-MULTILIB_DIRNAMES      += thumb
-
-MULTILIB_OPTIONS       += march=armv6s-m/march=armv7-m/march=armv7e-m/march=armv7/march=armv8-m.base/march=armv8-m.main
-MULTILIB_DIRNAMES      += v6-m v7-m v7e-m v7-ar v8-m.base v8-m.main
-
-MULTILIB_OPTIONS       += mfpu=vfpv3-d16/mfpu=fpv4-sp-d16/mfpu=fpv5-sp-d16/mfpu=fpv5-d16
-MULTILIB_DIRNAMES      += fpv3 fpv4-sp fpv5-sp fpv5
-
-MULTILIB_OPTIONS       += mfloat-abi=softfp/mfloat-abi=hard
-MULTILIB_DIRNAMES      += softfp hard
+MULTI_FPU_OPTS_RM       = mfpu=vfpv3-d16/mfpu=fpv4-sp-d16/mfpu=fpv5-sp-d16/mfpu=fpv5-d16
+MULTI_FPU_DIRS_RM       = fpv3 fpv4-sp fpv5-sp fpv5
 
 
 # Option combinations to build library with
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 0b94bc1931a226e58d06a7ed5a726454142c006a..d91c82b569c017819cc2390085ed159e02929819 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1114,14 +1114,18 @@  for each target is given below.
 
 @table @code
 @item arm*-*-*
-@var{list} is one of@code{default}, @code{aprofile} or @code{rmprofile}.
-Specifying @code{default} is equivalent to omitting this option, ie. only the
-default runtime library will be enabled.  Specifying @code{aprofile} or
-@code{rmprofile} builds multilibs for a combination of ISA, architecture,
-FPU available and floating-point ABI.
+@var{list} is a comma separated list of @code{aprofile} and @code{rmprofile}
+to build multilibs for A or R and M architecture profiles respectively.  Note
+that, due to some limitation of the current multilib framework, using the
+combined @code{aprofile,rmprofile} multilibs selects in some cases a less
+optimal multilib than when using the multilib profile for the architecture
+targetted.  The special value @code{default} is also accepted and is equivalent
+to omitting the option, ie. only the default run-time library will be enabled.
 
 The table below gives the combination of ISAs, architectures, FPUs and
 floating-point ABIs for which multilibs are built for each accepted value.
+The union of these options is considered when specifying both @code{aprofile}
+and @code{rmprofile}.
 
 @multitable @columnfractions .15 .28 .30
 @item Option @tab aprofile @tab rmprofile