Move additional swift compiler flags from build-script to Package.swift

This allows for a more consistent build, independent of whether
build-script was used or not. This will allow us to use a unified build
directory for all packages depending on Swift later on.

Author: ahoppen

Package.swift

@@ -1,29 +1,60 @@
-// swift-tools-version:4.2
+// swift-tools-version:5.1
 
 import PackageDescription
+import Foundation
+
+#if os(Linux)
+import Glibc
+#else
+import Darwin.C
+#endif
 
 let package = Package(
   name: "SwiftSyntax",
   targets: [
     .target(name: "_CSwiftSyntax"),
-    .target(name: "SwiftSyntax", dependencies: ["_CSwiftSyntax"]),
     .testTarget(name: "SwiftSyntaxTest", dependencies: ["SwiftSyntax"], exclude: ["Inputs"]),
     .target(name: "SwiftSyntaxBuilder", dependencies: ["SwiftSyntax"]),
     .testTarget(name: "SwiftSyntaxBuilderTest", dependencies: ["SwiftSyntaxBuilder"]),
     .target(name: "lit-test-helper", dependencies: ["SwiftSyntax"])
+    // Also see targets added below
   ]
 )
 
-#if os(Linux)
-import Glibc
-#else
-import Darwin.C
-#endif
+let swiftSyntaxTarget: PackageDescription.Target
+
+/// If we are in a controlled CI environment, we can use internal compiler flags
+/// to speed up the build or improve it.
+if getenv("SWIFT_SYNTAX_CI_ENVIRONMENT") != nil {
+  let groupFile = URL(fileURLWithPath: #file)
+    .deletingLastPathComponent()
+    .appendingPathComponent("utils")
+    .appendingPathComponent("group.json")
+
+  var swiftSyntaxUnsafeFlags = ["-Xfrontend", "-group-info-path",
+                                "-Xfrontend", groupFile.path]
+  // Enforcing exclusivity increases compile time of release builds by 2 minutes.
+  // Disable it when we're in a controlled CI environment.
+  swiftSyntaxUnsafeFlags += ["-enforce-exclusivity=unchecked"]
 
-if getenv("SWIFT_SYNTAX_BUILD_SCRIPT") == nil {
-  package.products.append(.library(name: "SwiftSyntax", targets: ["SwiftSyntax"]))
-  package.products.append(.library(name: "SwiftSyntaxBuilder", targets: ["SwiftSyntaxBuilder"]))
+  swiftSyntaxTarget = .target(name: "SwiftSyntax", dependencies: ["_CSwiftSyntax"],
+                              swiftSettings: [.unsafeFlags(swiftSyntaxUnsafeFlags)]
+  )
 } else {
-  package.products.append(.library(name: "SwiftSyntax", type: .dynamic, targets: ["SwiftSyntax"]))
-  package.products.append(.library(name: "SwiftSyntaxBuilder", type: .dynamic, targets: ["SwiftSyntaxBuilder"]))
+  swiftSyntaxTarget = .target(name: "SwiftSyntax", dependencies: ["_CSwiftSyntax"])
 }
+
+package.targets.append(swiftSyntaxTarget)
+
+let libraryType: Product.Library.LibraryType
+
+/// When we're in a CI environment, we want to build a dylib instead of a static
+/// library since we install the dylib into the toolchain.
+if getenv("SWIFT_SYNTAX_CI_ENVIRONMENT") != nil {
+  libraryType = .dynamic
+} else {
+  libraryType = .static
+}
+
+package.products.append(.library(name: "SwiftSyntax", type: libraryType, targets: ["SwiftSyntax"]))
+package.products.append(.library(name: "SwiftSyntaxBuilder", type: libraryType, targets: ["SwiftSyntaxBuilder"]))

build-script.py

@@ -87,7 +87,7 @@ def check_gyb_exec():
 
 
 def check_rsync():
-    with open(os.devnull, 'w')  as DEVNULL:
+    with open(os.devnull, 'w') as DEVNULL:
         if call(['rsync', '--version'], stdout=DEVNULL) != 0:
             fatal_error('Error: Could not find rsync.')
 
@@ -155,11 +155,8 @@ def generate_gyb_files(verbose, add_source_locations, destination=None):
 
 ## Building swiftSyntax
 
-def get_installed_name():
-    return 'SwiftSyntax'
-
 def get_installed_dylib_name():
-    return 'lib' + get_installed_name() + '.dylib'
+    return 'libSwiftSyntax.dylib'
 
 def get_swiftpm_invocation(toolchain, action, build_dir, release):
     swift_exec = os.path.join(toolchain, 'usr', 'bin', 'swift')
@@ -171,11 +168,6 @@ def get_swiftpm_invocation(toolchain, action, build_dir, release):
     if build_dir:
         swiftpm_call.extend(['--build-path', build_dir])
 
-    # Swift compiler needs to know the module link name.
-    swiftpm_call.extend(['-Xswiftc', '-module-link-name', '-Xswiftc', get_installed_name()])
-
-    # To speed up compilation.
-    swiftpm_call.extend(['-Xswiftc', '-enforce-exclusivity=unchecked'])
     return swiftpm_call
 
 class Builder(object):
@@ -190,20 +182,15 @@ def __init__(self, toolchain, build_dir, release, verbose,
       if verbose:
           self.swiftpm_call.extend(['--verbose'])
       self.verbose = verbose
-      self._environ = dict(os.environ)
-      self._environ['SWIFT_SYNTAX_BUILD_SCRIPT'] = ''
 
   def build(self, product_name, module_group_path=''):
       print('** Building ' + product_name + ' **')
       command = list(self.swiftpm_call)
       command.extend(['--product', product_name])
 
-      # To build the group information into the module documentation file
-      if module_group_path:
-        command.extend(['-Xswiftc', '-Xfrontend', '-Xswiftc', '-group-info-path'])
-        command.extend(['-Xswiftc', '-Xfrontend', '-Xswiftc', module_group_path])
-
-      check_call(command, env=self._environ, verbose=self.verbose)
+      env = dict(os.environ)
+      env['SWIFT_SYNTAX_CI_ENVIRONMENT'] = '1'
+      check_call(command, env=env, verbose=self.verbose)
 
 
 ## Testing
@@ -313,9 +300,15 @@ def run_lit_tests(toolchain, build_dir, release, filecheck_exec, verbose):
 
 def run_xctests(toolchain, build_dir, release, verbose):
     print('** Running XCTests **')
+
+    # Testing builds with testability enabled. Don't overwrite the
+    # build that we have just created and which shall be reused by
+    # dependent projects. Instead, build in a new directory.
+    test_build_dir = os.path.join(realpath(build_dir), 'test-build')
+
     swiftpm_call = get_swiftpm_invocation(toolchain=toolchain,
                                           action='test',
-                                          build_dir=build_dir,
+                                          build_dir=test_build_dir,
                                           release=release)
 
     if verbose:
@@ -390,7 +383,7 @@ def main():
 
     basic_group = parser.add_argument_group('Basic')
 
-    basic_group.add_argument('--build-dir', default=None, help='''
+    basic_group.add_argument('--build-dir', default='.build', help='''
         The directory in which build products shall be put. If omitted a
         directory named '.build' will be put in the swift-syntax directory.
         ''')
@@ -508,8 +501,6 @@ def main():
                           release=args.release,
                           verbose=args.verbose,
                           disable_sandbox=args.disable_sandbox)
-        # TODO: Building with group info does not allow us to reuse the build
-        # for running the tests.
         builder.build('SwiftSyntax', module_group_path=GROUP_INFO_PATH)
 
         # Only build lit-test-helper if we are planning to run tests
@@ -524,7 +515,7 @@ def main():
     if args.test:
         try:
             success = run_tests(toolchain=args.toolchain,
-                                build_dir=realpath(args.build_dir),
+                                build_dir=args.build_dir,
                                 release=args.release,
                                 filecheck_exec=realpath(args.filecheck_exec),
                                 verbose=args.verbose)