[CMake] Updates to allow inclusion using FetchContent

Various updates that allow swift-syntax to be included using
FetchContent.

Mostly this is just not replacing `target_link_libraries` since that is
a global replacement, but we also now use a couple of variables from the
swift if they're set (eg. `SWIFT_HOST_LIBRARIES_DEST_DIR` and
`SWIFT_HOST_MODULE_TRIPLE`).

Author: bnbarham

CMakeLists.txt

@@ -15,11 +15,22 @@ project(SwiftSyntax LANGUAGES C Swift)
 set(SWIFT_VERSION 5)
 set(CMAKE_Swift_LANGUAGE_VERSION ${SWIFT_VERSION})
 
+if(CMAKE_VERSION VERSION_LESS 3.21)
+  get_property(parent_dir DIRECTORY PROPERTY PARENT_DIRECTORY)
+  if(NOT parent_dir)
+    set(PROJECT_IS_TOP_LEVEL TRUE)
+  endif()
+endif()
+
 # The subdirectory into which host libraries will be installed.
 set(SWIFT_HOST_LIBRARIES_SUBDIRECTORY "swift/host")
-
-set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib/${SWIFT_HOST_LIBRARIES_SUBDIRECTORY}")
-set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib/${SWIFT_HOST_LIBRARIES_SUBDIRECTORY}")
+if(SWIFT_HOST_LIBRARIES_DEST_DIR)
+  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${SWIFT_HOST_LIBRARIES_DEST_DIR}")
+  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${SWIFT_HOST_LIBRARIES_DEST_DIR}")
+else()
+  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib/${SWIFT_HOST_LIBRARIES_SUBDIRECTORY}")
+  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib/${SWIFT_HOST_LIBRARIES_SUBDIRECTORY}")
+endif()
 
 set(CMAKE_MACOSX_RPATH YES)
 
@@ -50,22 +61,25 @@ if (NOT SWIFT_SUPPORTS_DISABLE_IMPLICIT_STRING_PROCESSING_MODULE_IMPORT)
 endif()
 
 # Determine the module triple.
-# FIXME: This is a hack. It's all a hack. Windows isn't setting
-# CMAKE_Swift_COMPILER_TARGET.
-if(CMAKE_Swift_COMPILER_TARGET)
-  string(REGEX REPLACE "macosx[0-9]+([.][0-9]+)?" "macos" SWIFT_MODULE_TRIPLE
-    ${CMAKE_Swift_COMPILER_TARGET})
-elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
-  if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64|AMD64")
-    set(SWIFT_MODULE_TRIPLE "x86_64-unknown-windows-msvc")
-  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64|ARM64|arm64")
-    set(SWIFT_MODULE_TRIPLE "aarch64-unknown-windows-msvc")
+if("${SWIFT_HOST_MODULE_TRIPLE}" STREQUAL "")
+  # FIXME: This is a hack. It's all a hack. Windows isn't setting
+  # CMAKE_Swift_COMPILER_TARGET.
+  if(CMAKE_Swift_COMPILER_TARGET)
+    string(REGEX REPLACE "macosx[0-9]+([.][0-9]+)?" "macos" SWIFT_HOST_MODULE_TRIPLE
+      ${CMAKE_Swift_COMPILER_TARGET})
+  elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
+    if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64|AMD64")
+      set(SWIFT_HOST_MODULE_TRIPLE "x86_64-unknown-windows-msvc")
+    elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64|ARM64|arm64")
+      set(SWIFT_HOST_MODULE_TRIPLE "aarch64-unknown-windows-msvc")
+    else()
+      message(FATAL_ERROR "Unrecognized architecture for Windows host")
+    endif()
   else()
-    message(FATAL_ERROR "Unrecognized architecture for Windows host")
+    message(FATAL_ERROR "Host module triple required")
   endif()
 endif()
-
-message(STATUS "Module triple: ${SWIFT_MODULE_TRIPLE}")
+message(STATUS "Module triple: ${SWIFT_HOST_MODULE_TRIPLE}")
 
 # Force single-threaded-only syntax trees to eliminate the Darwin
 # dependency in the compiler.
@@ -80,9 +94,9 @@ endif()
 
 add_subdirectory(Sources)
 
-export(EXPORT SwiftSyntaxTargets
-       FILE "${CMAKE_CURRENT_BINARY_DIR}/cmake/SwiftSyntaxTargets.cmake"
-       NAMESPACE SwiftSyntax::
-)
-
-add_subdirectory(cmake/modules)
+if(PROJECT_IS_TOP_LEVEL)
+  export(EXPORT SwiftSyntaxTargets
+         FILE "${CMAKE_CURRENT_BINARY_DIR}/cmake/SwiftSyntaxTargets.cmake"
+         NAMESPACE SwiftSyntax::
+  )
+endif()

Sources/CMakeLists.txt

@@ -6,31 +6,6 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-# cmake generation for Swift adds an order only dependency, which matches how C-family languages
-# works. In that case, however, ninja (and presumably other generators) will rebuild on header
-# changes. That's not the case for Swift, and thus if A -> B, A is not being rebuilt when the
-# ABI/API of B changes.
-#
-# For now workaround this by touching a file whenever B is rebuilt and then compiling that file as
-# part of A. Ideally this file would be generated by each of the targets, but that dependency didn't
-# seem to be being tracked.
-#
-# Remove once rdar://102202478 is fixed.
-function(target_link_libraries TARGET)
-  cmake_parse_arguments(ARGS "" "" "PUBLIC" ${ARGN})
-
-  _target_link_libraries(${TARGET} PUBLIC ${ARGS_PUBLIC})
-  foreach(DEPENDENCY ${ARGS_PUBLIC})
-    add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/forced-${DEPENDENCY}-dep.swift
-      COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/forced-${DEPENDENCY}-dep.swift
-      DEPENDS ${DEPENDENCY}
-      )
-    target_sources(${TARGET} PRIVATE
-      ${CMAKE_CURRENT_BINARY_DIR}/forced-${DEPENDENCY}-dep.swift
-    )
-  endforeach()
-endfunction()
-
 add_subdirectory(SwiftBasicFormat)
 add_subdirectory(SwiftSyntax)
 add_subdirectory(SwiftDiagnostics)

Sources/SwiftBasicFormat/CMakeLists.txt

@@ -6,12 +6,12 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftBasicFormat
+add_swift_syntax_library(SwiftBasicFormat
   BasicFormat.swift
   generated/BasicFormat+Extensions.swift
   SyntaxProtocol+Formatted.swift
   Trivia+FormatExtensions.swift
 )
 
-target_link_libraries(SwiftBasicFormat PUBLIC
+target_link_swift_syntax_libraries(SwiftBasicFormat PUBLIC
   SwiftSyntax)

Sources/SwiftCompilerPluginMessageHandling/CMakeLists.txt

@@ -6,15 +6,15 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftCompilerPluginMessageHandling
+add_swift_syntax_library(SwiftCompilerPluginMessageHandling
   CompilerPluginMessageHandler.swift
   Diagnostics.swift
   Macros.swift
   PluginMacroExpansionContext.swift
   PluginMessages.swift
 )
 
-target_link_libraries(SwiftCompilerPluginMessageHandling PUBLIC
+target_link_swift_syntax_libraries(SwiftCompilerPluginMessageHandling PUBLIC
   SwiftSyntax
   SwiftBasicFormat
   SwiftDiagnostics

Sources/SwiftDiagnostics/CMakeLists.txt

@@ -6,7 +6,7 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftDiagnostics
+add_swift_syntax_library(SwiftDiagnostics
   Diagnostic.swift
   DiagnosticsFormatter.swift
   FixIt.swift
@@ -15,5 +15,5 @@ add_swift_host_library(SwiftDiagnostics
   Note.swift
 )
 
-target_link_libraries(SwiftDiagnostics PUBLIC
+target_link_swift_syntax_libraries(SwiftDiagnostics PUBLIC
   SwiftSyntax)

Sources/SwiftIDEUtils/CMakeLists.txt

@@ -6,11 +6,11 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftIDEUtils
+add_swift_syntax_library(SwiftIDEUtils
   generated/SyntaxClassification.swift
   Syntax+Classifications.swift
   SyntaxClassifier.swift
 )
 
-target_link_libraries(SwiftIDEUtils PUBLIC
+target_link_swift_syntax_libraries(SwiftIDEUtils PUBLIC
   SwiftSyntax)

Sources/SwiftOperators/CMakeLists.txt

@@ -6,7 +6,7 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftOperators
+add_swift_syntax_library(SwiftOperators
   Operator.swift
   OperatorError+Diagnostics.swift
   OperatorError.swift
@@ -19,7 +19,7 @@ add_swift_host_library(SwiftOperators
   SyntaxSynthesis.swift
 )
 
-target_link_libraries(SwiftOperators PUBLIC
+target_link_swift_syntax_libraries(SwiftOperators PUBLIC
   SwiftSyntax
   SwiftDiagnostics
   SwiftParser)

Sources/SwiftParser/CMakeLists.txt

@@ -6,7 +6,7 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftParser
+add_swift_syntax_library(SwiftParser
   Attributes.swift
   Availability.swift
   CharacterInfo.swift
@@ -49,6 +49,6 @@ add_swift_host_library(SwiftParser
   Lexer/UnicodeScalarExtensions.swift
 )
 
-target_link_libraries(SwiftParser PUBLIC
+target_link_swift_syntax_libraries(SwiftParser PUBLIC
   SwiftSyntax
   SwiftDiagnostics)

Sources/SwiftParserDiagnostics/CMakeLists.txt

@@ -6,7 +6,7 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftParserDiagnostics
+add_swift_syntax_library(SwiftParserDiagnostics
   DiagnosticExtensions.swift
   LexerDiagnosticMessages.swift
   MissingNodesError.swift
@@ -23,7 +23,7 @@ add_swift_host_library(SwiftParserDiagnostics
   generated/TokenNameForDiagnostics.swift
 )
 
-target_link_libraries(SwiftParserDiagnostics PUBLIC
+target_link_swift_syntax_libraries(SwiftParserDiagnostics PUBLIC
   SwiftBasicFormat
   SwiftDiagnostics
   SwiftParser

Sources/SwiftSyntax/CMakeLists.txt

@@ -6,7 +6,7 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-add_swift_host_library(SwiftSyntax
+add_swift_syntax_library(SwiftSyntax
   AbsolutePosition.swift
   Assert.swift
   BumpPtrAllocator.swift