[overlay] Make an overlay for the clang _Builtin_float module

Clang's builtin float.h is no longer included in OS/SDK modules, and so it needs its own overlay.

rdar://122351557

Author: ian-twilightcoder

CMakeLists.txt

@@ -238,6 +238,10 @@ option(SWIFT_STDLIB_ENABLE_UNICODE_DATA
     NOTE: Disabling this will cause many String methods to crash."
     TRUE)
 
+option(SWIFT_BUILD_CLANG_OVERLAYS
+  "Build Swift overlays for the clang builtin modules"
+  TRUE)
+
 option(SWIFT_BUILD_DYNAMIC_SDK_OVERLAY
     "Build dynamic variants of the Swift SDK overlay"
     TRUE)

stdlib/linker-support/previous-module-installname.json

@@ -0,0 +1,6 @@
+[
+  {
+    "module": "Darwin",
+    "install_name": "/usr/lib/swift/libswiftDarwin.dylib"
+  }
+]

stdlib/public/CMakeLists.txt

@@ -250,6 +250,10 @@ if(SWIFT_BUILD_STDLIB AND NOT SWIFT_STDLIB_BUILD_ONLY_CORE_MODULES)
   # In some internal Apple configurations we have the need
   # to build Core and Onone separately from the rest
   # of the stdlib
+  if(SWIFT_BUILD_CLANG_OVERLAYS)
+    add_subdirectory(ClangOverlays)
+  endif()
+
   if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
     add_subdirectory(Differentiation)
   endif()

stdlib/public/ClangOverlays/CMakeLists.txt

@@ -0,0 +1,19 @@
+add_swift_target_library(swift_Builtin_float
+    ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES}
+    IS_SDK_OVERLAY
+
+    "${SWIFT_SOURCE_DIR}/stdlib/linker-support/magic-symbols-for-install-name.c"
+
+    GYB_SOURCES
+      float.swift.gyb
+
+    SWIFT_COMPILE_FLAGS
+      ${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}
+      ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+      -Xfrontend -previous-module-installname-map-file -Xfrontend "${SWIFT_SOURCE_DIR}/stdlib/linker-support/previous-module-installname.json"
+
+    LINK_FLAGS
+      ${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}
+
+    INSTALL_IN_COMPONENT stdlib
+    MACCATALYST_BUILD_FLAVOR zippered)

stdlib/public/ClangOverlays/float.swift.gyb

@@ -0,0 +1,59 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2018 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
+//
+//===----------------------------------------------------------------------===//
+
+@_exported import _Builtin_float
+
+@available(swift, deprecated: 3.0, message: "Please use 'T.radix' to get the radix of a FloatingPoint type 'T'.")
+public let FLT_RADIX = Double.radix
+
+%for type, prefix in [('Float', 'FLT'), ('Double', 'DBL'), ('Float80', 'LDBL')]:
+% if type == "Float80":
+#if !os(Android) && !os(WASI) && !os(Windows) && (arch(i386) || arch(x86_64))
+% end
+//  Where does the 1 come from? C counts the usually-implicit leading
+//  significand bit, but Swift does not. Neither is really right or wrong.
+@available(swift, deprecated: 3.0, message: "Please use '${type}.significandBitCount + 1'.")
+@_originallyDefinedIn(module: "Darwin", SwiftStdlib 5.11)
+public let ${prefix}_MANT_DIG = ${type}.significandBitCount + 1
+
+//  Where does the 1 come from? C models floating-point numbers as having a
+//  significand in [0.5, 1), but Swift (following IEEE 754) considers the
+//  significand to be in [1, 2). This rationale applies to ${prefix}_MIN_EXP
+//  as well.
+@available(swift, deprecated: 3.0, message: "Please use '${type}.greatestFiniteMagnitude.exponent + 1'.")
+@_originallyDefinedIn(module: "Darwin", SwiftStdlib 5.11)
+public let ${prefix}_MAX_EXP = ${type}.greatestFiniteMagnitude.exponent + 1
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNormalMagnitude.exponent + 1'.")
+@_originallyDefinedIn(module: "Darwin", SwiftStdlib 5.11)
+public let ${prefix}_MIN_EXP = ${type}.leastNormalMagnitude.exponent + 1
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.greatestFiniteMagnitude' or '.greatestFiniteMagnitude'.")
+@_originallyDefinedIn(module: "Darwin", SwiftStdlib 5.11)
+public let ${prefix}_MAX = ${type}.greatestFiniteMagnitude
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.ulpOfOne' or '.ulpOfOne'.")
+@_originallyDefinedIn(module: "Darwin", SwiftStdlib 5.11)
+public let ${prefix}_EPSILON = ${type}.ulpOfOne
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNormalMagnitude' or '.leastNormalMagnitude'.")
+@_originallyDefinedIn(module: "Darwin", SwiftStdlib 5.11)
+public let ${prefix}_MIN = ${type}.leastNormalMagnitude
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNonzeroMagnitude' or '.leastNonzeroMagnitude'.")
+@_originallyDefinedIn(module: "Darwin", SwiftStdlib 5.11)
+public let ${prefix}_TRUE_MIN = ${type}.leastNonzeroMagnitude
+
+% if type == "Float80":
+#endif
+% end
+%end

utils/build-script-impl

@@ -146,6 +146,7 @@ KNOWN_SETTINGS=(
     ## Build ...
     build-llvm                                    "1"               "set to 1 to build LLVM and Clang"
     build-sil-debugging-stdlib                    "0"               "set to 1 to build the Swift standard library with -sil-based-debuginfo to enable debugging and profiling on SIL level"
+    build-swift-clang-overlays                    "1"               "set to 1 to build the Swift overlays for the clang builtin modules"
     build-swift-dynamic-sdk-overlay               ""                "set to 1 to build dynamic variants of the Swift SDK overlay"
     build-swift-dynamic-stdlib                    ""                "set to 1 to build dynamic variants of the Swift standard library"
     build-swift-examples                          "1"               "set to 1 to build examples"
@@ -1870,6 +1871,7 @@ for host in "${ALL_HOSTS[@]}"; do
                     -DSWIFT_NATIVE_CLANG_TOOLS_PATH:STRING="${native_clang_tools_path}"
                     -DSWIFT_NATIVE_SWIFT_TOOLS_PATH:STRING="${native_swift_tools_path}"
                     -DSWIFT_INCLUDE_TOOLS:BOOL=$(true_false "${BUILD_SWIFT_TOOLS}")
+                    -DSWIFT_BUILD_CLANG_OVERLAYS:BOOL=$(true_false "${BUILD_SWIFT_CLANG_OVERLAYS}")
                     -DSWIFT_BUILD_REMOTE_MIRROR:BOOL=$(true_false "${BUILD_SWIFT_REMOTE_MIRROR}")
                     -DSWIFT_BUILD_EXTERNAL_GENERIC_METADATA_BUILDER:BOOL=$(true_false "${BUILD_SWIFT_EXTERNAL_GENERIC_METADATA_BUILDER}")
                     -DSWIFT_STDLIB_SIL_DEBUGGING:BOOL=$(true_false "${BUILD_SIL_DEBUGGING_STDLIB}")

utils/build_swift/build_swift/driver_arguments.py

@@ -1093,6 +1093,10 @@ def create_argument_parser():
            help='Include Unicode data in the standard library.'
                 'Note: required for full String functionality')
 
+    option('--build-swift-clang-overlays', toggle_true,
+           default=True,
+           help='Build Swift overlays for the clang builtin modules')
+
     option('--build-swift-remote-mirror', toggle_true,
            default=True,
            help='Build Remote Mirror')

utils/build_swift/tests/expected_options.py

@@ -89,6 +89,7 @@
     'build_swift_stdlib_unittest_extra': False,
     'build_swift_stdlib_static_print': False,
     'build_swift_stdlib_unicode_data': True,
+    'build_swift_clang_overlays': True,
     'build_swift_remote_mirror': True,
     'build_swiftpm': False,
     'build_swift_driver': False,
@@ -578,6 +579,7 @@ class BuildScriptImplOption(_BaseOption):
     EnableOption('--build-swift-private-stdlib'),
     EnableOption('--build-swift-stdlib-unicode-data'),
     EnableOption('--build-swift-libexec'),
+    EnableOption('--build-swift-clang-overlays'),
     EnableOption('--build-swift-remote-mirror'),
     EnableOption('--build-swift-external-generic-metadata-builder'),
     EnableOption('--cross-compile-append-host-target-to-destdir'),

utils/swift_build_support/swift_build_support/build_script_invocation.py

@@ -134,6 +134,8 @@ def convert_to_impl_arguments(self):
             "--dsymutil-jobs", str(args.dsymutil_jobs),
             '--build-swift-libexec', str(args.build_swift_libexec).lower(),
             '--swift-enable-backtracing', str(args.swift_enable_backtracing).lower(),
+            '--build-swift-clang-overlays', str(
+                args.build_swift_clang_overlays).lower(),
             '--build-swift-remote-mirror', str(args.build_swift_remote_mirror).lower(),
             '--build-swift-external-generic-metadata-builder', str(
                 args.build_swift_external_generic_metadata_builder).lower(),