Add a script that emits a JSON representation of wasm-delegations-fields.def

scripts/gen-delegations-json.py

@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+#
+# Copyright 2024 WebAssembly Community Group participants
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# Generates a json file that represents the contents of
+# wasm-delegations-fields.def, that is, with a structural description of all the
+# subclasses of Expression that make up the core of Binaryen IR. This can be
+# useful to automate bindings generation.
+#
+# To run this, just run the script and it outputs the json to stdout. The output
+# contains things like this:
+#
+#   {
+#     id: 'Block',
+#     fields: [
+#       {
+#         form: 'CHILD_VECTOR',
+#         name: 'list',
+#       },
+#       {
+#         form: 'SCOPE_NAME_DEF',
+#         name: 'name',
+#       },
+#     ]
+#   },
+#
+# This describes an Expression type "Block", whose first field "list" is a
+# CHILD_VECTOR, that is, a vector of children, and whose second field "name" is
+# a scope name definition. For example, consider this block:
+#
+#   (block $foo
+#     (nop)
+#     (unreachable)
+#   )
+#
+# In the IR for this block, the field "name" will contain "foo", and the field
+# "list" will contain a vector with a pointer to a Nop expression and an
+# Unreachable expression. For more details on what the forms mean, see
+# wasm-delegations-fields.def.
+#
+
+import os, sys
+
+binaryen_root = os.path.dirname(os.path.dirname(__file__))
+delegations_filename = os.path.join(binaryen_root, 'src', 'wasm-delegations-fields.def')
+
+print('[')
+
+for l in open(delegations_filename).read().splitlines():
+    # We seek lines like
+    #
+    # DELEGATE_FIELD_FOO(bar, baz)
+    #
+    # which we parse into the command (FOO) and args (bar, baz).
+    if not l.startswith('DELEGATE_FIELD') or '(' not in l:
+        continue
+    command, after = l.split('(')
+    command = command[15:]
+    args, _ = after.split(')')
+    args = [arg.strip() for arg in args.split(',')]
+    if command == 'CASE_START':
+        print(f'''  {{
+    id: '{args[0]}',
+    fields: [''')
+    elif command == 'CASE_END':
+        print('    ]\n  },')
+    elif len(args) == 2:
+        # e.g.
+        #
+        # DELEGATE_FIELD_CHILD(ArrayFill, value)
+        print(f'''      {{
+        form: '{command}',
+        name: '{args[1]}',
+      }},''')
+    elif len(args) == 3:
+        # e.g.
+        #
+        # DELEGATE_FIELD_NAME_KIND(ArrayInitData, segment, ModuleItemKind::DataSegment)
+        kind = args[2].split('::')[1]
+        print(f'''      {{
+        form: '{command}',
+        name: '{args[1]}',
+        kind: '{kind}',
+      }},''')
+    else:
+        raise Exception(l)
+
+print(']')
+

test/lit/gen-delegations-json.test

@@ -0,0 +1,25 @@
+
+;; RUN: gen-delegations-json.py > %t.js
+
+;; Verify that we emit valid JSON from the delegations tool.
+;; RUN: nodejs %t.js
+
+;; Verify that it contains things we expect, for example If.
+;; RUN: cat %t.js | filecheck %s --check-prefix=CHECK
+;; CHECK:    id: 'If',
+;; CHECK-NEXT:    fields: [
+;; CHECK-NEXT:      {
+;; CHECK-NEXT:        form: 'OPTIONAL_CHILD',
+;; CHECK-NEXT:        name: 'ifFalse',
+;; CHECK-NEXT:      },
+;; CHECK-NEXT:      {
+;; CHECK-NEXT:        form: 'CHILD',
+;; CHECK-NEXT:        name: 'ifTrue',
+;; CHECK-NEXT:      },
+;; CHECK-NEXT:      {
+;; CHECK-NEXT:        form: 'CHILD',
+;; CHECK-NEXT:        name: 'condition',
+;; CHECK-NEXT:      },
+;; CHECK-NEXT:    ]
+;; CHECK-NEXT:  },
+

test/lit/lit.cfg.py

@@ -20,6 +20,15 @@
     tool = tool_file[:-4] if tool_file.endswith('.exe') else tool_file
     config.substitutions.append((tool, tool_path))
 
+# Replace all Binaryen scripts with their absolute paths
+binaryen_src_root = os.path.dirname(os.path.dirname(config.test_source_root))
+scripts_dir = os.path.join(binaryen_src_root, 'scripts')
+assert(os.path.isdir(scripts_dir))
+
+for script_file in os.listdir(scripts_dir):
+    script_path = os.path.join(scripts_dir, script_file)
+    config.substitutions.append((script_file, script_path))
+
 # Also make the `not` and `foreach` commands available
 for tool in ('not', 'foreach'):
     tool_file = config.binaryen_src_root + '/scripts/' + tool + '.py'