sim_if/modelsim: use vmap to find modelsim.ini

* This creates a single source of truth for finding modelsim.ini. It is
  now possible to use MODELSIM=/path/to/custom/modelsim.ini and both
  ModelSim and vunit will use that. (The VUNIT_MODELSIM_INI environment
  variable can still be used to override modelsim.ini only for vunit.)

* This fixes detecting modelsim.ini in the quartus-prime-lite package
  from https://github.com/nixos/nixpkgs, which exposes binaries at
  $prefix/bin, but has no $prefix/modelsim.ini, because the latter would
  be an FHS violation.

tests/unit/test_modelsim_interface.py

@@ -22,14 +22,27 @@
 from vunit.vhdl_standard import VHDL
 
 
+def _get_test_path():
+    return Path(__file__).parent / "test_modelsim_out"
+
+
+def _get_prefix_path():
+    return _get_test_path() / "prefix" / "bin"
+
+
+def _get_installed_modelsim_ini():
+    return (_get_prefix_path() / ".." / "modelsim.ini").resolve()
+
+
 class TestModelSimInterface(unittest.TestCase):
     """
     Test the ModelSim interface
     """
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_vhdl_2008(self, process, check_output):
+    def test_compile_project_vhdl_2008(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -50,9 +63,10 @@ def test_compile_project_vhdl_2008(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_vhdl_2002(self, process, check_output):
+    def test_compile_project_vhdl_2002(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -73,9 +87,10 @@ def test_compile_project_vhdl_2002(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_vhdl_93(self, process, check_output):
+    def test_compile_project_vhdl_93(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -96,9 +111,10 @@ def test_compile_project_vhdl_93(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_vhdl_extra_flags(self, process, check_output):
+    def test_compile_project_vhdl_extra_flags(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -122,9 +138,10 @@ def test_compile_project_vhdl_extra_flags(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_verilog(self, process, check_output):
+    def test_compile_project_verilog(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -146,9 +163,10 @@ def test_compile_project_verilog(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_system_verilog(self, process, check_output):
+    def test_compile_project_system_verilog(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -171,9 +189,10 @@ def test_compile_project_system_verilog(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_verilog_extra_flags(self, process, check_output):
+    def test_compile_project_verilog_extra_flags(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -198,9 +217,10 @@ def test_compile_project_verilog_extra_flags(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_verilog_include(self, process, check_output):
+    def test_compile_project_verilog_include(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -223,9 +243,10 @@ def test_compile_project_verilog_include(self, process, check_output):
         ]
         check_output.assert_called_once_with(check_args, env=simif.get_env())
 
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
-    def test_compile_project_verilog_define(self, process, check_output):
+    def test_compile_project_verilog_define(self, process, check_output, get_modelsim_ini):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", "lib_path")
@@ -251,11 +272,12 @@ def test_compile_project_verilog_define(self, process, check_output):
     def _get_inis(self):
         return (
             str(Path(self.output_path) / "modelsim.ini"),
-            str(Path(self.prefix_path) / ".." / "modelsim.ini"),
+            str(_get_installed_modelsim_ini()),
             str(Path(self.test_path) / "my_modelsim.ini"),
         )
 
-    def test_copies_modelsim_ini_file_from_install(self):
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
+    def test_copies_modelsim_ini_file_from_install(self, get_modelsim_ini):
         (modelsim_ini, installed_modelsim_ini, user_modelsim_ini) = self._get_inis()
 
         with open(installed_modelsim_ini, "w") as fptr:
@@ -268,7 +290,8 @@ def test_copies_modelsim_ini_file_from_install(self):
         with open(modelsim_ini, "r") as fptr:
             self.assertEqual(fptr.read(), "installed")
 
-    def test_copies_modelsim_ini_file_from_user(self):
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
+    def test_copies_modelsim_ini_file_from_user(self, get_modelsim_ini):
         (modelsim_ini, installed_modelsim_ini, user_modelsim_ini) = self._get_inis()
 
         with open(installed_modelsim_ini, "w") as fptr:
@@ -283,7 +306,8 @@ def test_copies_modelsim_ini_file_from_user(self):
         with open(modelsim_ini, "r") as fptr:
             self.assertEqual(fptr.read(), "user")
 
-    def test_overwrites_modelsim_ini_file_from_install(self):
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
+    def test_overwrites_modelsim_ini_file_from_install(self, get_modelsim_ini):
         (modelsim_ini, installed_modelsim_ini, user_modelsim_ini) = self._get_inis()
 
         with open(modelsim_ini, "w") as fptr:
@@ -299,7 +323,8 @@ def test_overwrites_modelsim_ini_file_from_install(self):
         with open(modelsim_ini, "r") as fptr:
             self.assertEqual(fptr.read(), "installed")
 
-    def test_overwrites_modelsim_ini_file_from_user(self):
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
+    def test_overwrites_modelsim_ini_file_from_user(self, get_modelsim_ini):
         (modelsim_ini, installed_modelsim_ini, user_modelsim_ini) = self._get_inis()
 
         with open(modelsim_ini, "w") as fptr:
@@ -318,10 +343,11 @@ def test_overwrites_modelsim_ini_file_from_user(self):
             self.assertEqual(fptr.read(), "user")
 
     @mock.patch("vunit.sim_if.modelsim.LOGGER", autospec=True)
+    @mock.patch("vunit.sim_if.modelsim.ModelSimInterface._get_modelsim_ini_from_vmap", return_value=_get_installed_modelsim_ini())
     @mock.patch("vunit.sim_if.check_output", autospec=True, return_value="")
     @mock.patch("vunit.sim_if.modelsim.Process", autospec=True)
     @mock.patch("vunit.sim_if.vsim_simulator_mixin.Process", autospec=True)
-    def test_optimize(self, vsim_simulator_mixin_process, modelsim_process, check_output, LOGGER):
+    def test_optimize(self, vsim_simulator_mixin_process, modelsim_process, check_output, get_modelsim_ini, LOGGER):
         simif = ModelSimInterface(prefix=self.prefix_path, output_path=self.output_path, persistent=False)
         project = Project()
         project.add_library("lib", str(Path(self.libraries_path) / "lib"))
@@ -361,18 +387,18 @@ def test_optimize(self, vsim_simulator_mixin_process, modelsim_process, check_ou
         LOGGER.error.assert_has_calls(expected_error_calls)
 
     def setUp(self):
-        self.test_path = str(Path(__file__).parent / "test_modelsim_out")
+        self.test_path = str(_get_test_path())
 
         self.output_path = str(Path(self.test_path) / "modelsim")
-        self.prefix_path = str(Path(self.test_path) / "prefix" / "bin")
+        self.prefix_path = str(_get_prefix_path)
         self.libraries_path = str(Path(self.output_path) / "libraries")
         self.simulation_output_path = str(Path(self.test_path) / "test_output" / "lib.tb")
         renew_path(self.test_path)
         renew_path(self.output_path)
         renew_path(self.prefix_path)
         renew_path(self.libraries_path)
         renew_path(self.simulation_output_path)
-        installed_modelsim_ini = str(Path(self.prefix_path) / ".." / "modelsim.ini")
+        installed_modelsim_ini = str(_get_installed_modelsim_ini())
         write_file(installed_modelsim_ini, "[Library]")
         self.project = Project()
         self.cwd = os.getcwd()

vunit/sim_if/modelsim.py

@@ -10,6 +10,7 @@
 
 from pathlib import Path
 import os
+import re
 import logging
 from threading import Lock, Event
 from time import sleep
@@ -84,11 +85,11 @@ def find_prefix_from_path(cls):
         """
         Find first valid modelsim toolchain prefix
         """
-
-        def has_modelsim_ini(path):
-            return os.path.isfile(str(Path(path).parent / "modelsim.ini"))
-
-        return cls.find_toolchain(["vsim"], constraints=[has_modelsim_ini])
+        def not_aldec_simulator(path):
+            is_active_hdl = cls.find_toolchain(["vsim", "avhdl"]) is not None
+            is_riviera = cls.find_toolchain(["vsim", "vsimsa"]) is not None
+            return not (is_active_hdl or is_riviera)
+        return cls.find_toolchain(["vsim"], constraints=[not_aldec_simulator])
 
     @classmethod
     def supports_vhdl_package_generics(cls):
@@ -126,6 +127,32 @@ def __init__(self, prefix, output_path, *, persistent=False, gui=False, debugger
         # Lock to access the two shared variables above
         self._shared_state_lock = Lock()
 
+    def _get_modelsim_ini_from_vmap(self):
+        """
+        Get the path to modelsim.ini, as used by vmap.
+
+        This means it listens to the MODELSIM environment variable, allowing
+        both vunit and other code/scripts to use the same modelsim.ini.
+        """
+        vmap_output = []
+        proc = Process([str(Path(self._prefix) / "vmap")])
+        try:
+            proc.consume_output(callback=lambda line: vmap_output.append(line))
+        except Process.NonZeroExitCode:
+            # The responsibility of this code is only detecting where
+            # modelsim.ini is, not to check that all libraries defined in it
+            # exist. So suppress non-zero exit codes.
+            pass
+        for line in vmap_output:
+            m = re.match(r"Reading (.*modelsim\.ini)", line)
+            if m is None:
+                continue
+            modelsim_ini = Path(m.group(1)).resolve()
+            if not modelsim_ini.exists():
+                raise FileNotFoundError(modelsim_ini)
+            return modelsim_ini
+        raise Exception("Failed to get the path to modelsim.ini from vmap")
+
     def _create_modelsim_ini(self):
         """
         Create the modelsim.ini file
@@ -134,7 +161,11 @@ def _create_modelsim_ini(self):
         if not file_exists(parent):
             os.makedirs(parent)
 
-        original_modelsim_ini = os.environ.get("VUNIT_MODELSIM_INI", str(Path(self._prefix).parent / "modelsim.ini"))
+        # Try vunit specific environment variable first, then query vmap, which
+        # reads the MODELSIM environment variable if it exists, then checks the
+        # current working directory and eventually falls back to modelsim.ini
+        # bundled with ModelSim.
+        original_modelsim_ini = os.environ.get("VUNIT_MODELSIM_INI", str(self._get_modelsim_ini_from_vmap()))
         with Path(original_modelsim_ini).open("rb") as fread:
             with Path(self._sim_cfg_file_name).open("wb") as fwrite:
                 fwrite.write(fread.read())