Use gnuconfig package for config file replacement for RISC-V. (#26364)

* Use gnuconfig package for config file replacement for RISC-V.

This extends the changes in #26035 to handle RISC-V. Before this change,
many packages fail to configure on riscv64 due to config.guess being too
old to know about RISC-V. This is seen out of the box when clingo fails
to build from source due to pkgconfig failing to configure, throwing
error: "configure: error: cannot guess build type; you must specify one".

* Add riscv64 architecture

* Update vendored archspec from upstream project.
These archspec updates include changes needed to support riscv64.

* Update archspec's __init__.py to reflect the commit hash of archspec being used.

5 files changed, 86 insertions, 10 deletions

diff --git a/lib/spack/external/__init__.py b/lib/spack/external/__init__.py
index 112ad9e9af..b2acccd8cc 100644
--- a/lib/spack/external/__init__.py
+++ b/lib/spack/external/__init__.py
@@ -11,7 +11,7 @@ archspec
 
 * Homepage: https://pypi.python.org/pypi/archspec
 * Usage: Labeling, comparison and detection of microarchitectures
-* Version: 0.1.2 (commit 8940a8b099a54ded21f8cf4314c4b83b558bb6d1)
+* Version: 0.1.2 (commit 85757b6666422fca86aa882a769bf78b0f992f54)
 
 argparse
 --------
diff --git a/lib/spack/external/archspec/README.md b/lib/spack/external/archspec/README.md
index 015eb684b5..fb1eaebda3 100644
--- a/lib/spack/external/archspec/README.md
+++ b/lib/spack/external/archspec/README.md
@@ -49,6 +49,19 @@ $ tox
   congratulations :)
 ```
 
+## Citing Archspec
+
+If you are referencing `archspec` in a publication, please cite the following
+paper:
+
+ * Massimiliano Culpo, Gregory Becker, Carlos Eduardo Arango Gutierrez, Kenneth
+   Hoste, and Todd Gamblin.
+   [**`archspec`: A library for detecting, labeling, and reasoning about
+   microarchitectures**](https://tgamblin.github.io/pubs/archspec-canopie-hpc-2020.pdf).
+   In *2nd International Workshop on Containers and New Orchestration Paradigms
+   for Isolated Environments in HPC (CANOPIE-HPC'20)*, Online Event, November
+   12, 2020.
+
 ## License
 
 Archspec is distributed under the terms of both the MIT license and the
diff --git a/lib/spack/external/archspec/cpu/detect.py b/lib/spack/external/archspec/cpu/detect.py
index 56b73b3a75..31cde2af6d 100644
--- a/lib/spack/external/archspec/cpu/detect.py
+++ b/lib/spack/external/archspec/cpu/detect.py
@@ -306,3 +306,22 @@ def compatibility_check_for_aarch64(info, target):
         and (target.vendor == vendor or target.vendor == "generic")
         and target.features.issubset(features)
     )
+
+
+@compatibility_check(architecture_family="riscv64")
+def compatibility_check_for_riscv64(info, target):
+    """Compatibility check for riscv64 architectures."""
+    basename = "riscv64"
+    uarch = info.get("uarch")
+
+    # sifive unmatched board
+    if uarch == "sifive,u74-mc":
+        uarch = "u74mc"
+    # catch-all for unknown uarchs
+    else:
+        uarch = "riscv64"
+
+    arch_root = TARGETS[basename]
+    return (target == arch_root or arch_root in target.ancestors) and (
+        target == uarch or target.vendor == "generic"
+    )
diff --git a/lib/spack/external/archspec/json/cpu/microarchitectures.json b/lib/spack/external/archspec/json/cpu/microarchitectures.json
index 40f59bfd9e..0be30c25e0 100644
--- a/lib/spack/external/archspec/json/cpu/microarchitectures.json
+++ b/lib/spack/external/archspec/json/cpu/microarchitectures.json
@@ -2017,6 +2017,44 @@
       "features": [],
       "compilers": {
       }
+    },
+    "riscv64": {
+      "from": [],
+      "vendor": "generic",
+      "features": [],
+      "compilers": {
+        "gcc": [
+          {
+            "versions": "7.1:",
+            "flags" : "-march=rv64gc"
+          }
+        ],
+        "clang": [
+          {
+            "versions": "9.0:",
+            "flags" : "-march=rv64gc"
+          }
+        ]
+      }
+    },
+    "u74mc": {
+      "from": ["riscv64"],
+      "vendor": "SiFive",
+      "features": [],
+      "compilers": {
+        "gcc": [
+          {
+            "versions": "10.2:",
+            "flags" : "-march=rv64gc -mtune=sifive-7-series"
+          }
+        ],
+        "clang" : [
+          {
+            "versions": "12.0:",
+            "flags" : "-march=rv64gc -mtune=sifive-7-series"
+          }
+        ]
+      }
     }
   },
   "feature_aliases": {
diff --git a/lib/spack/spack/build_systems/autotools.py b/lib/spack/spack/build_systems/autotools.py
index 9a00764e22..f6ac0b3821 100644
--- a/lib/spack/spack/build_systems/autotools.py
+++ b/lib/spack/spack/build_systems/autotools.py
@@ -60,16 +60,18 @@ class AutotoolsPackage(PackageBase):
     def patch_config_files(self):
         """
         Whether or not to update old ``config.guess`` and ``config.sub`` files
-        distributed with the tarball. This currently only applies to ``ppc64le:``
-        and ``aarch64:`` target architectures. The substitutes are taken from the
-        ``gnuconfig`` package, which is automatically added as a build dependency
-        for these architectures. In case system versions of these config files are
-        required, the ``gnuconfig`` package can be marked external with a prefix
-        pointing to the directory containing the system ``config.guess`` and
-        ``config.sub`` files.
+        distributed with the tarball. This currently only applies to
+        ``ppc64le:``, ``aarch64:``, and ``riscv64`` target architectures. The
+        substitutes are taken from the ``gnuconfig`` package, which is
+        automatically added as a build dependency for these architectures. In
+        case system versions of these config files are required, the
+        ``gnuconfig`` package can be marked external with a prefix pointing to
+        the directory containing the system ``config.guess`` and ``config.sub``
+        files.
         """
         return (self.spec.satisfies('target=ppc64le:')
-                or self.spec.satisfies('target=aarch64:'))
+                or self.spec.satisfies('target=aarch64:')
+                or self.spec.satisfies('target=riscv64:'))
 
     #: Whether or not to update ``libtool``
     #: (currently only for Arm/Clang/Fujitsu compilers)
@@ -99,6 +101,7 @@ class AutotoolsPackage(PackageBase):
 
     depends_on('gnuconfig', type='build', when='target=ppc64le:')
     depends_on('gnuconfig', type='build', when='target=aarch64:')
+    depends_on('gnuconfig', type='build', when='target=riscv64:')
 
     @property
     def _removed_la_files_log(self):
@@ -121,7 +124,8 @@ class AutotoolsPackage(PackageBase):
         """Some packages ship with older config.guess/config.sub files and
         need to have these updated when installed on a newer architecture.
         In particular, config.guess fails for PPC64LE for version prior
-        to a 2013-06-10 build date (automake 1.13.4) and for ARM (aarch64).
+        to a 2013-06-10 build date (automake 1.13.4) and for ARM (aarch64) and
+        RISC-V (riscv64).
         """
         if not self.patch_config_files:
             return
@@ -133,6 +137,8 @@ class AutotoolsPackage(PackageBase):
             config_arch = 'ppc64le'
         elif self.spec.satisfies('target=aarch64:'):
             config_arch = 'aarch64'
+        elif self.spec.satisfies('target=riscv64:'):
+            config_arch = 'riscv64'
         else:
             config_arch = 'local'