Compilers can inject first order rules into the solver

* Restore PackageBase class, and modify only ASP

  This prevents a noticeable slowdown in concretization
  due to the number of directives involved.

* Fix issue with 'clang' being preferred to 'gcc',
  due to runtime version weights

* Constraints on runtimes are declared by compilers

  The declaration of available runtime versions, and of
  their compatibility constraints are in the associated
  compiler class.

Co-authored-by: Harmen Stoppels <harmenstoppels@gmail.com>

7 files changed, 103 insertions, 70 deletions

diff --git a/var/spack/repos/builtin/packages/gcc-runtime/package.py b/var/spack/repos/builtin/packages/gcc-runtime/package.py
index f0cd13dd14..ff13e05476 100644
--- a/var/spack/repos/builtin/packages/gcc-runtime/package.py
+++ b/var/spack/repos/builtin/packages/gcc-runtime/package.py
@@ -20,6 +20,8 @@ class GccRuntime(Package):
     homepage = "https://gcc.gnu.org"
     has_code = False
 
+    tags = ["runtime"]
+
     maintainers("haampie")
 
     license("GPL-3.0-or-later WITH GCC-exception-3.1")
@@ -42,76 +44,6 @@ class GccRuntime(Package):
         "ubsan",
     ]
 
-    for v in [
-        "13.2",
-        "13.1",
-        "12.3",
-        "12.2",
-        "12.1",
-        "11.4",
-        "11.3",
-        "11.2",
-        "11.1",
-        "10.5",
-        "10.4",
-        "10.3",
-        "10.2",
-        "10.1",
-        "9.5",
-        "9.4",
-        "9.3",
-        "9.2",
-        "9.1",
-        "8.5",
-        "8.4",
-        "8.3",
-        "8.2",
-        "8.1",
-        "7.5",
-        "7.4",
-        "7.3",
-        "7.2",
-        "7.1",
-        "6.5",
-        "6.4",
-        "6.3",
-        "6.2",
-        "6.1",
-        "5.5",
-        "5.4",
-        "5.3",
-        "5.2",
-        "5.1",
-        "4.9.4",
-        "4.9.3",
-        "4.9.2",
-        "4.9.1",
-        "4.9.0",
-        "4.8.5",
-        "4.8.4",
-        "4.8.3",
-        "4.8.2",
-        "4.8.1",
-        "4.8.0",
-        "4.7.4",
-        "4.7.3",
-        "4.7.2",
-        "4.7.1",
-        "4.7.0",
-        "4.6.4",
-        "4.6.3",
-        "4.6.2",
-        "4.6.1",
-        "4.6.0",
-        "4.5.4",
-        "4.5.3",
-        "4.5.2",
-        "4.5.1",
-        "4.5.0",
-    ]:
-        version(v)
-        requires(f"%gcc@{v}", when=f"@{v}")
-
     def install(self, spec, prefix):
         if spec.platform in ["linux", "cray", "freebsd"]:
             libraries = self._get_libraries_elf()
diff --git a/var/spack/repos/builtin/packages/gcc/package.py b/var/spack/repos/builtin/packages/gcc/package.py
index f6dce2ea00..2fb8d23aed 100644
--- a/var/spack/repos/builtin/packages/gcc/package.py
+++ b/var/spack/repos/builtin/packages/gcc/package.py
@@ -1111,3 +1111,32 @@ class Gcc(AutotoolsPackage, GNUMirrorPackage):
                         ),
                     ),
                 )
+
+    @classmethod
+    def runtime_constraints(cls, *, compiler, pkg):
+        """Callback function to inject runtime-related rules into the solver.
+
+        Rule-injection is obtained through method calls of the ``pkg`` argument.
+
+        Documentation for this function is temporary. When the API will be in its final state,
+        we'll document the behavior at https://spack.readthedocs.io/en/latest/
+
+        Args:
+            compiler: compiler object (node attribute) currently considered
+            pkg: object used to forward information to the solver
+        """
+        pkg("*").depends_on(
+            "gcc-runtime",
+            when="%gcc",
+            type="link",
+            description="If any package uses %gcc, it depends on gcc-runtime",
+        )
+        pkg("*").depends_on(
+            f"gcc-runtime@{str(compiler.version)}:",
+            when=f"%{str(compiler.spec)}",
+            type="link",
+            description=f"If any package uses %{str(compiler.spec)}, "
+            f"it depends on gcc-runtime@{str(compiler.version)}:",
+        )
+        # The version of gcc-runtime is the same as the %gcc used to "compile" it
+        pkg("gcc-runtime").requires(f"@={str(compiler.version)}", when=f"%{str(compiler.spec)}")
diff --git a/var/spack/repos/compiler_runtime.test/packages/a/package.py b/var/spack/repos/compiler_runtime.test/packages/a/package.py
new file mode 100644
index 0000000000..1f68aadc2f
--- /dev/null
+++ b/var/spack/repos/compiler_runtime.test/packages/a/package.py
@@ -0,0 +1,13 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+from spack.package import *
+
+
+class A(Package):
+    homepage = "http://www.example.com"
+    has_code = False
+
+    version("1.0")
+    depends_on("b")
diff --git a/var/spack/repos/compiler_runtime.test/packages/b/package.py b/var/spack/repos/compiler_runtime.test/packages/b/package.py
new file mode 100644
index 0000000000..ab9f3150e6
--- /dev/null
+++ b/var/spack/repos/compiler_runtime.test/packages/b/package.py
@@ -0,0 +1,12 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+from spack.package import *
+
+
+class B(Package):
+    homepage = "http://www.example.com"
+    has_code = False
+
+    version("1.0")
diff --git a/var/spack/repos/compiler_runtime.test/packages/gcc-runtime/package.py b/var/spack/repos/compiler_runtime.test/packages/gcc-runtime/package.py
new file mode 100644
index 0000000000..61d40a2df6
--- /dev/null
+++ b/var/spack/repos/compiler_runtime.test/packages/gcc-runtime/package.py
@@ -0,0 +1,13 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack.package import *
+
+
+class GccRuntime(Package):
+    homepage = "https://example.com"
+    has_code = False
+    tags = ["runtime"]
+    requires("%gcc")
diff --git a/var/spack/repos/compiler_runtime.test/packages/gcc/package.py b/var/spack/repos/compiler_runtime.test/packages/gcc/package.py
new file mode 100644
index 0000000000..db81066599
--- /dev/null
+++ b/var/spack/repos/compiler_runtime.test/packages/gcc/package.py
@@ -0,0 +1,32 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack.package import *
+
+
+class Gcc(Package):
+    homepage = "http://www.example.com/"
+    has_code = False
+
+    version("13.2.0")
+    version("12.3.0")
+
+    @classmethod
+    def runtime_constraints(cls, *, compiler, pkg):
+        pkg("*").depends_on(
+            "gcc-runtime",
+            when="%gcc",
+            type="link",
+            description="If any package uses %gcc, it depends on gcc-runtime",
+        )
+        pkg("*").depends_on(
+            f"gcc-runtime@{str(compiler.version)}:",
+            when=f"%{str(compiler.spec)}",
+            type="link",
+            description=f"If any package uses %{str(compiler.spec)}, "
+            f"it depends on gcc-runtime@{str(compiler.version)}:",
+        )
+        # The version of gcc-runtime is the same as the %gcc used to "compile" it
+        pkg("gcc-runtime").requires(f"@={str(compiler.version)}", when=f"%{str(compiler.spec)}")
diff --git a/var/spack/repos/compiler_runtime.test/repo.yaml b/var/spack/repos/compiler_runtime.test/repo.yaml
new file mode 100644
index 0000000000..1be826a641
--- /dev/null
+++ b/var/spack/repos/compiler_runtime.test/repo.yaml
@@ -0,0 +1,2 @@
+repo:
+  namespace: compiler_runtime.test