Implement warning for non-deterministic selection of virtual cores

fusesoc/coremanager.py

@@ -225,14 +225,36 @@ def eq_vln(this, that):
         except NoPackageFound as e:
             raise DependencyError(top_core.name)
 
+        virtual_selection = {}
         objdict = {}
         if len(transaction.operations) > 1:
             for op in transaction.operations:
+                package_name = self._package_name(op.package.core.name)
+                virtuals = op.package.core.get_virtuals(_flags)
                 for p in op.package.provides:
+                    for virtual in virtuals:
+                        if p[0] == self._package_name(virtual):
+                            # Add virtual core selection to dictionary
+                            virtual_selection[package_name] = (
+                                op.package.core.name,
+                                virtual,
+                            )
                     objdict[p[0]] = str(op.package.core.name)
+                for p in op.package.install_requires:
+                    if p[0] in virtual_selection:
+                        # If package that implements a virtual core is required, remove from the dictionary
+                        del virtual_selection[p[0]]
                 op.package.core.direct_deps = [
                     objdict[n[0]] for n in op.package.install_requires
                 ]
+        # Print a warning for all virtual selections that has no concrete requirement selection
+        for virtual in virtual_selection.values():
+            logger.warning(
+                "Non-deterministic selection of virtual core {} selected {}".format(
+                    virtual[1], virtual[0]
+                )
+            )
+
         result = [op.package.core for op in transaction.operations]
 
         # Cache the solution for further lookups

tests/capi2_cores/virtual/top_conflict.core

@@ -0,0 +1,22 @@
+CAPI=2:
+# Copyright FuseSoC contributors
+# Licensed under the 2-Clause BSD License, see LICENSE for details.
+# SPDX-License-Identifier: BSD-2-Clause
+
+name: ::top_conflict:0
+filesets:
+  rtl:
+    depend:
+      - ::user:0
+      - ::impl1:0
+      - ::impl2:0
+    files:
+      - top_conflict.sv
+    file_type: systemVerilogSource
+
+
+targets:
+  default:
+    filesets:
+      - rtl
+    toplevel: top_impl2

tests/capi2_cores/virtual/top_non_deterministic.core

@@ -0,0 +1,19 @@
+CAPI=2:
+# Copyright FuseSoC contributors
+# Licensed under the 2-Clause BSD License, see LICENSE for details.
+# SPDX-License-Identifier: BSD-2-Clause
+
+name: ::top_non_deterministic:0
+filesets:
+  rtl:
+    depend:
+      - ::user:0
+    files:
+      - top_impl1.sv
+    file_type: systemVerilogSource
+
+targets:
+  default:
+    filesets:
+      - rtl
+    toplevel: top_impl1

tests/test_coremanager.py

@@ -278,3 +278,90 @@ def test_virtual():
         deps_names = [str(c) for c in deps]
 
         assert deps_names == expected_deps
+
+
+def test_virtual_conflict():
+    """
+    Test virtual core selection when there are more than one selected implementation.
+    This shall result in a conflict of cores.
+    """
+    import os
+    import tempfile
+
+    from fusesoc.config import Config
+    from fusesoc.coremanager import CoreManager, DependencyError
+    from fusesoc.edalizer import Edalizer
+    from fusesoc.librarymanager import Library
+    from fusesoc.vlnv import Vlnv
+
+    flags = {"tool": "icarus"}
+
+    build_root = tempfile.mkdtemp(prefix="export_")
+    work_root = os.path.join(build_root, "work")
+
+    core_dir = os.path.join(os.path.dirname(__file__), "capi2_cores", "virtual")
+
+    cm = CoreManager(Config())
+    cm.add_library(Library("virtual", core_dir), [])
+
+    root_core = cm.get_core(Vlnv("::top_conflict"))
+
+    edalizer = Edalizer(
+        toplevel=root_core.name,
+        flags=flags,
+        core_manager=cm,
+        work_root=work_root,
+    )
+    with pytest.raises(DependencyError) as _:
+        edalizer.run()
+
+
+def test_virtual_non_deterministic_virtual(caplog):
+    """
+    Test virtual core selection when there are no selected implementations.
+    This shall result in a warning that the virtual core selection is non-deteministic.
+    """
+    import logging
+    import os
+    import tempfile
+
+    from fusesoc.config import Config
+    from fusesoc.coremanager import CoreManager
+    from fusesoc.edalizer import Edalizer
+    from fusesoc.librarymanager import Library
+    from fusesoc.vlnv import Vlnv
+
+    flags = {"tool": "icarus"}
+
+    build_root = tempfile.mkdtemp(prefix="export_")
+    work_root = os.path.join(build_root, "work")
+
+    core_dir = os.path.join(os.path.dirname(__file__), "capi2_cores", "virtual")
+
+    cm = CoreManager(Config())
+    cm.add_library(Library("virtual", core_dir), [])
+
+    root_core = cm.get_core(Vlnv("::top_non_deterministic"))
+
+    edalizer = Edalizer(
+        toplevel=root_core.name,
+        flags=flags,
+        core_manager=cm,
+        work_root=work_root,
+    )
+    edalizer.run()
+
+    with caplog.at_level(logging.WARNING):
+        edalizer.run()
+    assert "Non-deterministic selection of virtual core" in caplog.text
+
+    deps = cm.get_depends(root_core.name, {})
+    deps_names = [str(c) for c in deps]
+
+    for dependency in deps_names:
+        assert dependency in [
+            "::impl1:0",
+            "::impl2:0",
+            "::user:0",
+            "::top_non_deterministic:0",
+        ]