Add CBMC proof-running GitHub Action (#924)

This commit adds a GitHub Action that runs the CBMC proofs upon every
push and pull request. This is intended to replace the current CBMC CI.

FreeRTOS/Test/CBMC/proofs/lib/print_tool_versions.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+#
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: MIT-0
+
+
+import logging
+import pathlib
+import shutil
+import subprocess
+
+
+_TOOLS = [
+    "cadical",
+    "cbmc",
+    "cbmc-viewer",
+    "cbmc-starter-kit-update",
+    "kissat",
+    "litani",
+]
+
+
+def _format_versions(table):
+    lines = [
+        "<table>",
+        '<tr><td colspan="2" style="font-weight: bold">Tool Versions</td></tr>',
+    ]
+    for tool, version in table.items():
+        if version:
+            v_str = f'<code><pre style="margin: 0">{version}</pre></code>'
+        else:
+            v_str = '<em>not found</em>'
+        lines.append(
+            f'<tr><td style="font-weight: bold; padding-right: 1em; '
+            f'text-align: right;">{tool}:</td>'
+            f'<td>{v_str}</td></tr>')
+    lines.append("</table>")
+    return "\n".join(lines)
+
+
+def _get_tool_versions():
+    ret = {}
+    for tool in _TOOLS:
+        err = f"Could not determine version of {tool}: "
+        ret[tool] = None
+        if not shutil.which(tool):
+            logging.error("%s'%s' not found on $PATH", err, tool)
+            continue
+        cmd = [tool, "--version"]
+        proc = subprocess.Popen(cmd, text=True, stdout=subprocess.PIPE)
+        try:
+            out, _ = proc.communicate(timeout=10)
+        except subprocess.TimeoutExpired:
+            logging.error("%s'%s --version' timed out", err, tool)
+            continue
+        if proc.returncode:
+            logging.error(
+                "%s'%s --version' returned %s", err, tool, str(proc.returncode))
+            continue
+        ret[tool] = out.strip()
+    return ret
+
+
+def main():
+    exe_name = pathlib.Path(__file__).name
+    logging.basicConfig(format=f"{exe_name}: %(message)s")
+
+    table = _get_tool_versions()
+    out = _format_versions(table)
+    print(out)
+
+
+if __name__ == "__main__":
+    main()