Armcompiler (#9840)

* Initial compiler support

* added arm.py

* Changed licence to Arm suggested header

* Changed licence to the same as clang.py
Main author of file is Nick Forrington <Nick.Forrington@arm.com>
Minor changes by Srinath Vadlamani <srinath.vadlamani@arm.com>

* compilers: add arm compiler detection to Spack

- added arm.py with support for detecting `armclang` and `armflang`

Co-authored-by: Srinath Vadlamani <srinath.vadlamani@arm.com>

* Changed to using get get_compiler_version

* linking to general cc for arm compiler

* For arm compiler add CFLAGS to use compiler-rt rtlib.

* Escape for special characters in rexep

* Cleaned up for Flake8 to pass.

* libcompiler-rt should be part of the LDFLAGS not CFLAGS

* fixed m4 when using clang to used LDFLAGS.  Fixed comments for arm.py to display compiler --version output with # NOAQ for flakes pass.

* added arm compilers

* proper linked names

6 files changed, 29 insertions, 27 deletions

diff --git a/lib/spack/env/arm/armclang b/lib/spack/env/arm/armclang
new file mode 120000
index 0000000000..82c2b8e90a
--- /dev/null
+++ b/lib/spack/env/arm/armclang
@@ -0,0 +1 @@
+../cc
\ No newline at end of file
diff --git a/lib/spack/env/arm/armclang++ b/lib/spack/env/arm/armclang++
new file mode 120000
index 0000000000..82c2b8e90a
--- /dev/null
+++ b/lib/spack/env/arm/armclang++
@@ -0,0 +1 @@
+../cc
\ No newline at end of file
diff --git a/lib/spack/env/arm/armflang b/lib/spack/env/arm/armflang
new file mode 120000
index 0000000000..82c2b8e90a
--- /dev/null
+++ b/lib/spack/env/arm/armflang
@@ -0,0 +1 @@
+../cc
\ No newline at end of file
diff --git a/lib/spack/env/cc b/lib/spack/env/cc
index 5e68702c5f..70f429055d 100755
--- a/lib/spack/env/cc
+++ b/lib/spack/env/cc
@@ -106,19 +106,19 @@ case "$command" in
     cpp)
         mode=cpp
         ;;
-    cc|c89|c99|gcc|clang|icc|pgcc|xlc|xlc_r)
+    cc|c89|c99|gcc|clang|armclang|icc|pgcc|xlc|xlc_r)
         command="$SPACK_CC"
         language="C"
         comp="CC"
         lang_flags=C
         ;;
-    c++|CC|g++|clang++|icpc|pgc++|xlc++|xlc++_r)
+    c++|CC|g++|clang++|armclang++|icpc|pgc++|xlc++|xlc++_r)
         command="$SPACK_CXX"
         language="C++"
         comp="CXX"
         lang_flags=CXX
         ;;
-    ftn|f90|fc|f95|gfortran|flang|ifort|pgfortran|xlf90|xlf90_r|nagfor)
+    ftn|f90|fc|f95|gfortran|flang|armflang|ifort|pgfortran|xlf90|xlf90_r|nagfor)
         command="$SPACK_FC"
         language="Fortran 90"
         comp="FC"
diff --git a/lib/spack/spack/compilers/arm.py b/lib/spack/spack/compilers/arm.py
index 33801a1ccc..b2c4871236 100644
--- a/lib/spack/spack/compilers/arm.py
+++ b/lib/spack/spack/compilers/arm.py
@@ -3,10 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
-import re
-
-from spack.compiler import Compiler, _version_cache
-from spack.util.executable import Executable
+from spack.compiler import Compiler, get_compiler_version
 
 
 class Arm(Compiler):
@@ -23,10 +20,10 @@ class Arm(Compiler):
     fc_names = ['armflang']
 
     # Named wrapper links within lib/spack/env
-    link_paths = {'cc': 'clang/clang',
-                  'cxx': 'clang/clang++',
-                  'f77': 'clang/flang',
-                  'fc': 'clang/flang'}
+    link_paths = {'cc': 'arm/armclang',
+                  'cxx': 'arm/armclang++',
+                  'f77': 'arm/armflang',
+                  'fc': 'arm/armflang'}
 
     @property
     def openmp_flag(self):
@@ -50,19 +47,19 @@ class Arm(Compiler):
 
     @classmethod
     def default_version(cls, comp):
-        if comp not in _version_cache:
-            compiler = Executable(comp)
-            output = compiler('--version', output=str, error=str)
-
-            ver = 'unknown'
-            match = re.search(r'Arm C/C++/Fortran Compiler version ([^ )]+)',
-                              output)
-            if match:
-                ver = match.group(1)
-
-            _version_cache[comp] = ver
-
-        return _version_cache[comp]
+        """The ``--version`` option seems to be the most consistent one
+        for arm compilers.  Output looks like this::
+
+            $ arm<c/f>lang --version
+            Arm C/C++/Fortran Compiler version 19.0 (build number 73) (based on LLVM 7.0.2) # NOQA
+            Target: aarch64--linux-gnu
+            Thread model: posix
+            InstalledDir:
+            /opt/arm/arm-hpc-compiler-19.0_Generic-AArch64_RHEL-7_aarch64-linux/bin # NOQA
+        """
+        return get_compiler_version(
+            comp, '--version',
+            r'Arm C\/C\+\+\/Fortran Compiler version ([^ )]+)')
 
     @classmethod
     def fc_version(cls, fc):
diff --git a/var/spack/repos/builtin/packages/m4/package.py b/var/spack/repos/builtin/packages/m4/package.py
index b14956e3ae..ad180b15a8 100644
--- a/var/spack/repos/builtin/packages/m4/package.py
+++ b/var/spack/repos/builtin/packages/m4/package.py
@@ -34,9 +34,11 @@ class M4(AutotoolsPackage):
         spec = self.spec
         args = ['--enable-c++']
 
-        if (spec.satisfies('%clang') or spec.satisfies('%arm')) and not \
-           spec.satisfies('platform=darwin'):
-            args.append('CFLAGS=-rtlib=compiler-rt')
+        if spec.satisfies('%clang') and not spec.satisfies('platform=darwin'):
+            args.append('LDFLAGS=-rtlib=compiler-rt')
+
+        if spec.satisfies('%arm') and not spec.satisfies('platform=darwin'):
+            args.append('LDFLAGS=-rtlib=compiler-rt')
 
         if spec.satisfies('%intel'):
             args.append('CFLAGS=-no-gcc')