Add a codesize check of the freestanding/minimal stdlib to prevent large codesize regressions (#40653)

test/CMakeLists.txt

@@ -94,6 +94,7 @@ function(get_test_dependencies SDK result_var_name)
       llvm-profdata
       llvm-readelf
       llvm-readobj
+      llvm-size
       llvm-strings
       not
       split-file)

test/lit.cfg

@@ -344,6 +344,7 @@ config.llvm_dwarfdump = inferSwiftBinary('llvm-dwarfdump')
 config.llvm_readelf = inferSwiftBinary('llvm-readelf')
 config.llvm_dis = inferSwiftBinary('llvm-dis')
 config.llvm_nm = inferSwiftBinary('llvm-nm')
+config.llvm_size = inferSwiftBinary('llvm-size')
 config.sourcekitd_test = inferSwiftBinary('sourcekitd-test')
 config.complete_test = inferSwiftBinary('complete-test')
 config.swift_api_digester = inferSwiftBinary('swift-api-digester')
@@ -516,6 +517,7 @@ config.substitutions.append( ('%llvm-dwarfdump', config.llvm_dwarfdump) )
 config.substitutions.append( ('%llvm-readelf', config.llvm_readelf) )
 config.substitutions.append( ('%llvm-dis', config.llvm_dis) )
 config.substitutions.append( ('%llvm-nm', config.llvm_nm) )
+config.substitutions.append( ('%llvm-size', config.llvm_size) )
 config.substitutions.append( ('%swift-demangle-yamldump', config.swift_demangle_yamldump) )
 config.substitutions.append( ('%swift-demangle', config.swift_demangle) )
 config.substitutions.append( ('%Benchmark_O', config.benchmark_o) )

test/stdlib/freestanding-check-size1.swift

@@ -0,0 +1,13 @@
+// Check that we can LTO-optimize the freestanding/minimal stdlib against client usage of APIs, and that we don't produce unexpectedly large final binary.
+
+// 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: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/a.out
+// RUN: %{python} %utils/check_freestanding_size.py --path %t/a.out --triple %module-target-triple --size-path %llvm-size
+
+print("Hello world")

test/stdlib/freestanding-check-size2.swift

@@ -0,0 +1,16 @@
+// Check that we can LTO-optimize the freestanding/minimal stdlib against client usage of APIs, and that we don't produce unexpectedly large final binary.
+
+// 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: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/a.out
+// RUN: %{python} %utils/check_freestanding_size.py --path %t/a.out --triple %module-target-triple --size-path %llvm-size
+
+let array = [1, 2, 3]
+let dict = ["abc": 42]
+let s = Set([1, 3, 5])
+print("Hello \(array) \(dict) \(s)")

utils/build-script-impl

@@ -1769,14 +1769,15 @@ for host in "${ALL_HOSTS[@]}"; do
                     # build of Swift depend on these for building and testing.
                     build_targets=(llvm-tblgen clang-resource-headers intrinsics_gen clang-tablegen-targets)
                     # If we are not performing a toolchain only build, then we
-                    # also want to include FileCheck, not, llvm-nm for testing
-                    # purposes.
+                    # also want to include FileCheck, not, llvm-nm, and similar
+                    # for testing purposes.
                     if [[ ! "${BUILD_TOOLCHAIN_ONLY}" ]] ; then
                       build_targets=(
                           "${build_targets[@]}"
                           FileCheck
                           not
                           llvm-nm
+                          llvm-size
                       )
                     fi
                 fi

utils/check_freestanding_size.py

@@ -0,0 +1,67 @@
+#!/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("--path", help="path to a binary to check")
+parser.add_argument("--triple", help="target triple of the freestanding stdlib")
+parser.add_argument("--size-path", help="path to llvm-size binary to use")
+args = parser.parse_args()
+
+
+################################################################################
+#
+# EXPECTED/ALLOWED TEXT SEGMENT SIZE
+#
+# Before bumping the maximum text segment size please consult with:
+# @kubamracek, @compnerd
+#
+# The 'freestanding' build of the Swift runtime and standard library is
+# intended to be lean and allow dead-code elimination from the standard library
+# based on client code usage.
+#
+################################################################################
+
+# As of 2022-01-05: TEXT segment is 640 KiB on x86_64 Darwin, stdlib without
+# asserts. Let's allow for some minor increases (~ 15%) and cap at 740 kiB:
+
+max_text_size_x86_64_apple_macos = 740 * 1024
+
+################################################################################
+
+
+if args.triple == "x86_64-apple-macos":
+    max_text_size = max_text_size_x86_64_apple_macos
+    actual_text_size = 0
+
+    nm = args.size_path
+    lines = subprocess.check_output(
+        [nm, "--format=darwin", args.path]) \
+        .decode("utf-8").strip().splitlines()
+    for line in lines:
+        if line.startswith("Segment __TEXT: "):
+            actual_text_size = int(line[len("Segment __TEXT: "):])
+
+    if actual_text_size == 0:
+        print("cannot determine TEXT segment size")
+        sys.exit(1)
+
+else:
+    print("triple {} not handled yet".format(args.triple))
+    sys.exit(1)
+
+print("max_text_size: %d" % max_text_size)
+print("actual_text_size: %d" % actual_text_size)
+fail = actual_text_size > max_text_size
+
+sys.exit(1 if fail else 0)