Deprecate the _warning statement

Author: mandolaerik

RELEASENOTES.md

@@ -200,3 +200,6 @@
   syntax is only permitted when this feature is enabled. his feature will be
   disabled in Simics API versions \> 7, where all uses of `vect` instead require
   explicit `provisional` declarations.
+- `note 6` The rarely used `_warning` statement has been deprecated, through
+  the introduction of a new compatibility feature `warning_statement`.
+  Warning statements will be illegal when Simics API 8 or newer is used.

dmlast.py

@@ -8,8 +8,11 @@ def create_dmlasts(dmlc_path, dmlast_path, dml_path, depfile):
     sys.path.append(str(dmlc_path))
     from dml.toplevel import produce_dmlast
     from dml.logging import ignore_warning
+    import dml.globals
+    from dml import compat
 
     ignore_warning('WEXPERIMENTAL')
+    dml.globals.enabled_compat.add(compat.warning_statement)
     dml_files_abs = list(dml_path.rglob('*.dml'))
     dml_files = [p.relative_to(dml_path) for p in dml_files_abs]
     assert dml_files

lib/1.2/dml-builtins.dml

@@ -224,6 +224,7 @@ template device {
     parameter _compat_dml12_misc auto;
     parameter _compat_dml12_int auto;
     parameter _compat_c_vect_without_provisional auto;
+    parameter _compat_warning_statement auto;
 
     // automatic parameters
     parameter obj                       auto;

lib/1.2/utility.dml

@@ -169,9 +169,12 @@ template write_only {
             log spec_viol, log_level, Register_Read:
                 "Read from write-only register %s (returning 0).", $qname;
             log_level = 2;
-        } else {
+        } else if ($dev._compat_warning_statement) {
             _warning "The write_only template only makes sense on registers."
                 + " For fields, use read_zero instead.";
+        } else {
+            error "The write_only template only makes sense on registers."
+                + " For fields, use read_zero instead.";
         }
         value = 0;
     }
@@ -541,8 +544,13 @@ template _unimpl_base_write_warn {
             }
             $this = value;
             if (defined ($reg.limitations)
-                && $reg.limitations == "Not implemented.")
-                _warning "unimplemented template used in both field and register";
+                && $reg.limitations == "Not implemented.") {
+                if ($dev._compat_warning_statement) {
+                    _warning "unimplemented template used in both field and register";
+                } else {
+                    error "unimplemented template used in both field and register";
+                }
+            }
         }
     }
 }

lib/1.4/dml-builtins.dml

@@ -626,6 +626,7 @@ template device {
     param _compat_dml12_misc auto;
     param _compat_dml12_int auto;
     param _compat_c_vect_without_provisional auto;
+    param _compat_warning_statement auto;
 
     // automatic parameters
     param obj                       auto;

py/dml/compat.py

@@ -392,3 +392,12 @@ class c_vect_without_provisional(CompatFeature):
     '''
     short = "Permit vect syntax without 'provisional c_vect'"
     last_api_version = api_7
+
+
+@feature
+class warning_statement(CompatFeature):
+    '''This compatibility feature enables the `_warning` statement.
+    This turned out to not be very useful, so in Simics API 8 and
+    newer the feature is no longer allowed.'''
+    short = "Allow the `_warning` statement"
+    last_api_version = api_7

py/dml/dmlparse.py

@@ -2498,6 +2498,8 @@ def warning_statement(t):
 @prod
 def warning_stmt(t):
     'warning_stmt : _WARNING bracketed_string_literal SEMI'
+    if compat.warning_statement not in dml.globals.enabled_compat:
+        raise ESYNTAX(site(t), '_warning', 'deprecated _warning statement')
     report(WEXPERIMENTAL(site(t), "_warning statement"))
     t[0] = ast.warning(site(t), t[2])
 

test/1.4/legacy/T_warning_statement_disabled.dml

@@ -0,0 +1,14 @@
+/*
+  © 2024 Intel Corporation
+  SPDX-License-Identifier: MPL-2.0
+*/
+dml 1.4;
+device test;
+
+/// DMLC-FLAG --simics-api=7
+/// DMLC-FLAG --no-compat=warning_statement
+
+method m() {
+    /// ERROR ESYNTAX
+    _warning "foo";
+}

test/1.4/legacy/T_warning_statement_enabled.dml

@@ -0,0 +1,15 @@
+/*
+  © 2024 Intel Corporation
+  SPDX-License-Identifier: MPL-2.0
+*/
+dml 1.4;
+device test;
+
+/// COMPILE-ONLY
+/// DMLC-FLAG --simics-api=7
+
+method m() {
+    // method is dead, so no WWRNSTMT
+    /// WARNING WEXPERIMENTAL
+    _warning "foo";
+}

test/tests.py

@@ -1452,6 +1452,7 @@ def test(self):
        ('utility.dml', None, 'PRENAME_TEMPLATE'),
        ('utility.dml', None, 'PABSTRACT_TEMPLATE'),
        ('utility.dml', None, 'PHASH'),
+       ('utility.dml', None, 'PHASHELSE'),
        ('utility.dml', None, 'PIFAND'),
        ('utility.dml', None, 'PANDOR'),
        ('utility.dml', None, 'PCHANGE_INARGS'),