Merge pull request swiftlang#39401 from kubamracek/enforce-undefined-symbols

Ensure that we only depend on a small expected set of external symbols in the freestanding stdlib

Author: kubamracek

test/stdlib/symbols-depended-on-in-freestanding.darwin.test-sh

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+// Ensure that we only depend on a small expected set of external symbols in the freestanding stdlib.
+
+// Important (!): This test is in test/stdlib/ to make sure it is actually run on the minimal/freestanding CI job, which
+// filters the set of tests to test/stdlib/ only (see build-preset.ini).
+
+// REQUIRES: freestanding
+// REQUIRES: executable_test
+
+// RUN: %{python} %utils/check_freestanding_dependencies.py --vendor %target-vendor --library %test-resource-dir/freestanding/libswiftCore.a --nm-path %llvm-nm

utils/check_freestanding_dependencies.py

@@ -0,0 +1,119 @@
+#!/usr/bin/env python
+#
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+import argparse
+import subprocess
+import sys
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--library", help="path to libswiftCore.a to check")
+parser.add_argument("--vendor", help="flavor of the freestanding stdlib")
+parser.add_argument("--nm-path", help="path to llvm-nm binary to use")
+args = parser.parse_args()
+
+
+################################################################################
+#
+# EXPECTED/ALLOWED DEPENDENCIES
+#
+# Before adding new symbols into these lists please consult with:
+# @kubamracek, @compnerd
+#
+# The 'freestanding' build of the Swift runtime and standard library is
+# intended to depend on as few platform symbols/APIs as possible.
+#
+################################################################################
+icu_dependencies = [
+    "_u_charAge", "_u_charName", "_u_getIntPropertyValue", "_u_getNumericValue",
+    "_u_hasBinaryProperty", "_u_strToLower", "_u_strToTitle", "_u_strToUpper",
+    "_ubrk_close", "_ubrk_following", "_ubrk_open", "_ubrk_preceding",
+    "_ubrk_setText", "_ubrk_setUText", "_unorm2_getNFCInstance",
+    "_unorm2_hasBoundaryBefore", "_unorm2_normalize",
+    "_unorm2_spanQuickCheckYes", "_utext_openUChars", "_utext_openUTF8",
+]
+cxx_dependencies = [
+    "___cxa_guard_acquire", "___cxa_guard_release",
+]
+math_dependencies = [
+    "_ceill", "_cos", "_cosf", "_cosl", "_exp", "_exp2", "_exp2f", "_exp2l",
+    "_expf", "_expl", "_fma", "_fmaf", "_fmal", "_fmod", "_fmodf", "_fmodl",
+    "_log", "_log10", "_log10f", "_log10l", "_log2", "_log2f", "_log2l",
+    "_logf", "_logl", "_nearbyintl", "_remainder", "_remainderf", "_remainderl",
+    "_rintl", "_roundl", "_sin", "_sinf", "_sinl", "_truncl",
+]
+common_expected_dependencies = [
+    "___bzero", "___divti3", "___error", "___stderrp", "___stdoutp",
+    "___truncsfhf2", "___udivti3", "_abort", "_arc4random_buf", "_backtrace",
+    "_calloc", "_close", "_environ", "_flockfile", "_floorl", "_fprintf",
+    "_fputc", "_fputs", "_free", "_funlockfile", "_fwrite", "_malloc",
+    "_malloc_size", "_memchr", "_memcmp", "_memcpy", "_memmove", "_memset",
+    "_posix_memalign", "_putc", "_read", "_realloc", "_snprintf", "_strchr",
+    "_strcmp", "_strdup", "_strlen", "_strncmp", "_strtod_l", "_strtof_l",
+    "_strtol", "_strtold_l", "_vsnprintf", "_write",
+] + icu_dependencies + cxx_dependencies + math_dependencies
+vendor_apple_specific_dependencies = [
+    "__NSGetArgc", "__NSGetArgv", "___stack_chk_fail", "___stack_chk_guard",
+    "_asl_log", "_getsectiondata", "__dyld_register_func_for_add_image",
+]
+################################################################################
+
+
+if args.vendor == "apple":
+    vendor_specific_dependencies = vendor_apple_specific_dependencies
+
+    nm = args.nm_path
+    lines = subprocess.check_output(
+        [nm, "--portability", "--undefined-only", args.library]) \
+        .decode("utf-8").strip().splitlines()
+    deps = [line.split(" ")[0] for line in lines if " U " in line]
+    print("")
+else:
+    print("vendor {} not handled yet".format(args.vendor))
+    sys.exit(1)
+
+deps = [dep for dep in deps if not dep.startswith("_$")]
+deps = [dep for dep in deps if not dep.startswith("__Z")]
+deps = [dep for dep in deps if not dep.startswith("section$start$")]
+deps = [dep for dep in deps if not dep.startswith("section$end$")]
+deps = [dep for dep in deps if not dep.startswith("___swift_stdlib")]
+deps = [dep for dep in deps if not dep.startswith("__swift_stdlib")]
+deps = [dep for dep in deps if not dep.startswith("__swift")]
+deps = [dep for dep in deps if not dep.startswith("_swift_")]
+deps = [dep for dep in deps if not dep.startswith("__stdlib_")]
+deps = [dep for dep in deps if not dep.startswith("_getSuperclassMetadata")]
+
+deps = set(deps)
+
+print("libswiftCore.a dependencies:")
+print("\n".join(sorted(deps)))
+print("")
+
+# for sanity checking that we are getting a valid symbol list
+required_dependencies = ["_malloc", "_free"]
+
+fail = False
+for symbol in required_dependencies:
+    if symbol not in deps:
+        print("Error: Required dependency '{}' missing".format(symbol))
+        fail = True
+
+allowlist = set(common_expected_dependencies + vendor_specific_dependencies)
+for symbol in deps:
+    if symbol not in allowlist:
+        print("Error: Unexpected dependency '{}'".format(symbol))
+        fail = True
+
+for symbol in allowlist:
+    if symbol not in deps:
+        print("Warning: Allowed dependency '{}' not present".format(symbol))
+
+print("")
+print("All checks done. Result: {}".format("FAIL" if fail else "SUCCESS"))
+sys.exit(1 if fail else 0)