[arm] Rewrite t-aprofile using new selector methodology

Now that the default FPU is 'auto' we can finally rewrite (and
simplify) the rules for mapping compiler options to multilibs.  We
no-longer need to know the specific CPU, since the driver will
construct a suitable -march flag for us; this greatly simplifies the
overall logic.  This patch rewrites the library list for A-profile
cores.  We use various Make extention rules to simplify the logic even
further.

A couple of minor tweaks to the configure script and to the main
driver ensures that we always know the setting of -mfloat-abi and
-marm/-mthumb.  Again, this helps simplify the logic further.  The
change to arm_target_thumb_only relies on the fact that this routine
is only called if neither -marm nor -mthumb has been previously
selected or specified by the user.

A new testsuite module is added to check the libraries generated.  The
new tests are only run if the compiler is configured with the relevant
multilibs enabled.

gcc:
	* config.gcc: (arm*-*-*): When building a-profile libraries, force
	the driver to pass through the default setting of -mfloat-abi.
	* common/config/arm/arm-common.c (arm_target_thumb_only): Return -marm
	rather than NULL.
	* config/arm/t-multilib (MULTILIB_REUSE): Initialize to empty.
	(all_feat_combs): New rule.
	(MULTILIB_OPTIONS): Use explicit ARM and Thumb directories.  Rework
	default libraries.
	* config/arm/t-aprofile: Rewrite.

gcc/testsuite:
	* gcc.target/arm/multilibs.exp: New file.

From-SVN: r249296

gcc/ChangeLog

 2017-06-16  Richard Earnshaw  <rearnsha@arm.com>
 
+	* config.gcc: (arm*-*-*): When building a-profile libraries, force
+	the driver to pass through the default setting of -mfloat-abi.
+	* common/config/arm/arm-common.c (arm_target_thumb_only): Return -marm
+	rather than NULL.
+	* config/arm/t-multilib (MULTILIB_REUSE): Initialize to empty.
+	(all_feat_combs): New rule.
+	(MULTILIB_OPTIONS): Use explicit ARM and Thumb directories.  Rework
+	default libraries.
+	* config/arm/t-aprofile: Rewrite.
+
+2017-06-16  Richard Earnshaw  <rearnsha@arm.com>
+
 	* config/arm/arm.h (FPUTYPE_AUTO): Define.
 	* config/arm/arm.c (arm_option_override): Use FPUTYPE_AUTO if the
 	fpu is not specified by the user/command-line.

gcc/common/config/arm/arm-common.c

@@ -215,7 +215,9 @@ arm_target_thumb_only (int argc, const char **argv)
 	return "-mthumb";
     }
 
-  return NULL;
+  /* Compiler hasn't been configured with a default, and the CPU
+     doesn't require Thumb, so default to ARM.  */
+  return "-marm";
 }
 
 /* List the permitted CPU option names.  If TARGET is a near miss for an

gcc/config.gcc

@@ -3856,7 +3856,9 @@ case "${target}" in
 				    echo "Error: You cannot use any of --with-arch/cpu/fpu/float/mode with --with-multilib-list=${with_multilib_list}" 1>&2
 				    exit 1
 				fi
-
+				# But pass the default value for float-abi
+				# through to the multilib selector
+				with_float="soft"
 				tmake_file="${tmake_file} ${tmake_profile_file}"
 				TM_MULTILIB_CONFIG="$with_multilib_list"
 			fi

gcc/config/arm/t-multilib

@@ -29,6 +29,7 @@ MULTILIB_DIRNAMES    =
 MULTILIB_EXCEPTIONS  =
 MULTILIB_MATCHES     =
 MULTILIB_REUSE	     =
+MULTILIB_REQUIRED    =
 
 comma := ,
 tm_multilib_list := $(subst $(comma), ,$(TM_MULTILIB_CONFIG))
@@ -36,6 +37,26 @@ tm_multilib_list := $(subst $(comma), ,$(TM_MULTILIB_CONFIG))
 HAS_APROFILE := $(filter aprofile,$(tm_multilib_list))
 HAS_RMPROFILE := $(filter rmprofile,$(tm_multilib_list))
 
+# Produce the combinatorial list of extensions.  Where there are
+# multiple permutations for a combination, the ordering is the
+# selected by the forward ordering of the original list.  This matches
+# the canonical ordering generated by the canonicalizer in the driver.
+#
+# For example,
+#   $(call all_feat_combs, a b)
+# will produce
+#   +a +a+b +b
+# but will not include
+#   +b+a
+# The rule is recursive and can be called with any (reasonable) list of
+# extensions.
+all_feat_combs	= +$(firstword $(1)) \
+		  $(if $(wordlist 2, $(words $(1)), $(1)), \
+		    $(foreach OPT, \
+		      $(call all_feat_combs, \
+		        $(wordlist 2, $(words $(1)), $(1))), \
+		      +$(firstword $(1))$(OPT) $(OPT)),)
+
 ifneq (,$(HAS_APROFILE))
 include $(srcdir)/config/arm/t-aprofile
 endif
@@ -45,25 +66,14 @@ 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       += marm/mthumb
+MULTILIB_DIRNAMES      += arm thumb
 
-MULTILIB_OPTIONS       += $(MULTI_ARCH_OPTS_A)$(SEP)$(MULTI_ARCH_OPTS_RM)
-MULTILIB_DIRNAMES      += $(MULTI_ARCH_DIRS_A) $(MULTI_ARCH_DIRS_RM)
+MULTILIB_OPTIONS       += march=armv5te+fp/$(MULTI_ARCH_OPTS_A)$(SEP)$(MULTI_ARCH_OPTS_RM)
+MULTILIB_DIRNAMES      += v5te $(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=soft/mfloat-abi=softfp/mfloat-abi=hard
+MULTILIB_DIRNAMES      += nofp softfp hard
 
-MULTILIB_OPTIONS       += mfloat-abi=softfp/mfloat-abi=hard
-MULTILIB_DIRNAMES      += softfp hard
+MULTILIB_REQUIRED      += mthumb/mfloat-abi=soft
+MULTILIB_REQUIRED      += marm/march=armv5te+fp/mfloat-abi=hard

gcc/testsuite/ChangeLog

+2017-06-16  Richard Earnshaw  <rearnsha@arm.com>
+
+	* gcc.target/arm/multilibs.exp: New file.
+
 2017-06-16  Martin Sebor  <msebor@redhat.com>
 
 	PR tree-optimization/80933