Build ppc64le docker images (#26442)

* Update archspec
* Add ppc64le to docker images

.github/workflows/build-containers.yml

@@ -26,10 +26,10 @@ jobs:
       # they support.
       matrix:
         dockerfile: [[amazon-linux, amazonlinux-2.dockerfile, 'linux/amd64,linux/arm64'],
-                     [centos7, centos-7.dockerfile, 'linux/amd64,linux/arm64'],
-                     [leap15, leap-15.dockerfile, 'linux/amd64,linux/arm64'],
-                     [ubuntu-xenial, ubuntu-1604.dockerfile, 'linux/amd64,linux/arm64'],
-                     [ubuntu-bionic, ubuntu-1804.dockerfile, 'linux/amd64,linux/arm64']]
+                     [centos7, centos-7.dockerfile, 'linux/amd64,linux/arm64,linux/ppc64le'],
+                     [leap15, leap-15.dockerfile, 'linux/amd64,linux/arm64,linux/ppc64le'],
+                     [ubuntu-xenial, ubuntu-1604.dockerfile, 'linux/amd64,linux/arm64,linux/ppc64le'],
+                     [ubuntu-bionic, ubuntu-1804.dockerfile, 'linux/amd64,linux/arm64,linux/ppc64le']]
     name: Build ${{ matrix.dockerfile[0] }}
     steps:
       - name: Checkout

lib/spack/external/__init__.py

@@ -11,7 +11,7 @@
 
 * Homepage: https://pypi.python.org/pypi/archspec
 * Usage: Labeling, comparison and detection of microarchitectures
-* Version: 0.1.2 (commit 4dbf253daf37e4a008e4beb6489f347b4a35aed4)
+* Version: 0.1.2 (commit 8940a8b099a54ded21f8cf4314c4b83b558bb6d1)
 
 argparse
 --------

lib/spack/external/archspec/cpu/detect.py

@@ -206,11 +206,26 @@ def host():
     # Get a list of possible candidates for this micro-architecture
     candidates = compatible_microarchitectures(info)
 
+    # Sorting criteria for candidates
+    def sorting_fn(item):
+        return len(item.ancestors), len(item.features)
+
+    # Get the best generic micro-architecture
+    generic_candidates = [c for c in candidates if c.vendor == "generic"]
+    best_generic = max(generic_candidates, key=sorting_fn)
+
+    # Filter the candidates to be descendant of the best generic candidate.
+    # This is to avoid that the lack of a niche feature that can be disabled
+    # from e.g. BIOS prevents detection of a reasonably performant architecture
+    candidates = [c for c in candidates if c > best_generic]
+
+    # If we don't have candidates, return the best generic micro-architecture
+    if not candidates:
+        return best_generic
+
     # Reverse sort of the depth for the inheritance tree among only targets we
     # can use. This gets the newest target we satisfy.
-    return sorted(
-        candidates, key=lambda t: (len(t.ancestors), len(t.features)), reverse=True
-    )[0]
+    return max(candidates, key=sorting_fn)
 
 
 def compatibility_check(architecture_family):
@@ -245,7 +260,13 @@ def compatibility_check_for_power(info, target):
     """Compatibility check for PPC64 and PPC64LE architectures."""
     basename = platform.machine()
     generation_match = re.search(r"POWER(\d+)", info.get("cpu", ""))
+    try:
         generation = int(generation_match.group(1))
+    except AttributeError:
+        # There might be no match under emulated environments. For instance
+        # emulating a ppc64le with QEMU and Docker still reports the host
+        # /proc/cpuinfo and not a Power
+        generation = 0
 
     # We can use a target if it descends from our machine type and our
     # generation (9 for POWER9, etc) is at least its generation.

lib/spack/external/archspec/cpu/microarchitecture.py

@@ -173,6 +173,12 @@ def family(self):
 
         return roots.pop()
 
+    @property
+    def generic(self):
+        """Returns the best generic architecture that is compatible with self"""
+        generics = [x for x in [self] + self.ancestors if x.vendor == "generic"]
+        return max(generics, key=lambda x: len(x.ancestors))
+
     def to_dict(self, return_list_of_items=False):
         """Returns a dictionary representation of this object.