concretizer: try hard to infer the real version of compilers (#20099)

fixes #20055

Compiler with custom versions like gcc@foo are not currently
matched to the appropriate targets. This is because the
version of spec doesn't match the "real" version of the
compiler.

This PR replicates the strategy used in the original
concretizer to deal with that and tries to detect the real
version of compilers if the version in the spec returns no
results.

3 files changed, 53 insertions, 3 deletions

diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index f0fa41fb6e..f4b2da319a 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -31,6 +31,7 @@ import llnl.util.tty.color as color
 import spack
 import spack.architecture
 import spack.cmd
+import spack.compilers
 import spack.config
 import spack.dependency
 import spack.error
@@ -829,6 +830,18 @@ class SpackSolverSetup(object):
             f = fn.default_compiler_preference(cspec.name, cspec.version, i)
             self.gen.fact(f)
 
+        # Enumerate target families. This may be redundant, but compilers with
+        # custom versions will be able to concretize properly.
+        for entry in spack.compilers.all_compilers_config():
+            compiler_entry = entry['compiler']
+            cspec = spack.spec.CompilerSpec(compiler_entry['spec'])
+            if not compiler_entry.get('target', None):
+                continue
+
+            self.gen.fact(fn.compiler_supports_target(
+                cspec.name, cspec.version, compiler_entry['target']
+            ))
+
     def compiler_supports_os(self):
         compilers_yaml = spack.compilers.all_compilers_config()
         for entry in compilers_yaml:
@@ -1230,7 +1243,7 @@ class SpackSolverSetup(object):
                 if dep.versions.concrete:
                     self.possible_versions[dep.name].add(dep.version)
 
-    def _supported_targets(self, compiler, targets):
+    def _supported_targets(self, compiler_name, compiler_version, targets):
         """Get a list of which targets are supported by the compiler.
 
         Results are ordered most to least recent.
@@ -1239,7 +1252,7 @@ class SpackSolverSetup(object):
 
         for target in targets:
             try:
-                target.optimization_flags(compiler.name, compiler.version)
+                target.optimization_flags(compiler_name, compiler_version)
                 supported.append(target)
             except archspec.cpu.UnsupportedMicroarchitecture:
                 continue
@@ -1289,7 +1302,22 @@ class SpackSolverSetup(object):
         # TODO: investigate this.
         best_targets = set([uarch.family.name])
         for compiler in sorted(compilers):
-            supported = self._supported_targets(compiler, compatible_targets)
+            supported = self._supported_targets(
+                compiler.name, compiler.version, compatible_targets
+            )
+
+            # If we can't find supported targets it may be due to custom
+            # versions in the spec, e.g. gcc@foo. Try to match the
+            # real_version from the compiler object to get more accurate
+            # results.
+            if not supported:
+                compiler_obj = spack.compilers.compilers_for_spec(compiler)
+                compiler_obj = compiler_obj[0]
+                supported = self._supported_targets(
+                    compiler.name,
+                    compiler_obj.real_version,
+                    compatible_targets
+                )
 
             if not supported:
                 continue
diff --git a/lib/spack/spack/test/concretize.py b/lib/spack/spack/test/concretize.py
index e5cd8b162a..8366ecca14 100644
--- a/lib/spack/spack/test/concretize.py
+++ b/lib/spack/spack/test/concretize.py
@@ -959,3 +959,11 @@ class TestConcretize(object):
         # Check that non-default variant values are forced on the dependency
         d = s['dep-with-variants']
         assert '+foo+bar+baz' in d
+
+    @pytest.mark.regression('20055')
+    def test_custom_compiler_version(self):
+        if spack.config.get('config:concretizer') == 'original':
+            pytest.xfail('Known failure of the original concretizer')
+
+        s = Spec('a %gcc@foo os=redhat6').concretized()
+        assert '%gcc@foo' in s
diff --git a/lib/spack/spack/test/data/config/compilers.yaml b/lib/spack/spack/test/data/config/compilers.yaml
index 3a63796941..641331dc9f 100644
--- a/lib/spack/spack/test/data/config/compilers.yaml
+++ b/lib/spack/spack/test/data/config/compilers.yaml
@@ -8,6 +8,7 @@ compilers:
       f77: None
       fc: None
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: gcc@4.5.0
     operating_system: {0.name}{0.version}
@@ -17,6 +18,7 @@ compilers:
       f77: None
       fc: None
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: clang@3.3
     operating_system: CNL
@@ -35,6 +37,7 @@ compilers:
       f77: None
       fc: None
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: clang@3.3
     operating_system: yosemite
@@ -44,6 +47,7 @@ compilers:
       f77: None
       fc: None
     modules: 'None'
+    target: x86_64
 - compiler:
     paths:
       cc: /path/to/gcc
@@ -62,6 +66,7 @@ compilers:
     operating_system: SuSE11
     spec: gcc@4.5.0
     modules: 'None'
+    target: x86_64
 - compiler:
     paths:
       cc: /path/to/gcc
@@ -71,6 +76,7 @@ compilers:
     operating_system: yosemite
     spec: gcc@4.5.0
     modules: 'None'
+    target: x86_64
 - compiler:
     paths:
       cc: /path/to/gcc
@@ -80,6 +86,7 @@ compilers:
     operating_system: elcapitan
     spec: gcc@4.5.0
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: clang@3.3
     operating_system: elcapitan
@@ -89,6 +96,7 @@ compilers:
       f77: None
       fc: None
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: gcc@4.7.2
     operating_system: redhat6
@@ -102,6 +110,7 @@ compilers:
       cxxflags: -O0 -g
       fflags: -O0 -g
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: gcc@4.4.0
     operating_system: redhat6
@@ -123,6 +132,7 @@ compilers:
       cflags: -O3
       cxxflags: -O3
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: clang@8.0.0
     operating_system: redhat7
@@ -135,6 +145,7 @@ compilers:
       cflags: -O3
       cxxflags: -O3
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: apple-clang@9.1.0
     operating_system: elcapitan
@@ -144,6 +155,7 @@ compilers:
       f77: None
       fc: None
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: gcc@foo
     operating_system: redhat6
@@ -153,6 +165,7 @@ compilers:
       f77: /path/to/gfortran
       fc: /path/to/gfortran
     modules: 'None'
+    target: x86_64
 - compiler:
     spec: gcc@4.4.0-special
     operating_system: redhat6
@@ -162,3 +175,4 @@ compilers:
       f77: /path/to/gfortran
       fc: /path/to/gfortran
     modules: 'None'
+    target: x86_64