Apple: Introduce separate system name for iOS, tvOS, and watchOS

- Remove code signing requirements for non-macOS
- Do not set deployment target for non-macOS
- Build static library for compiler feature detection for non-macOS
- Use framework to run CompilerId tests for watchOS
- Port tests to new SDK handling
- Add new Apple cross-compiling section to toolchain documentation

Closes: #17870

16 files changed, 66 insertions, 4 deletions

diff --git a/Modules/CMakeDetermineCCompiler.cmake b/Modules/CMakeDetermineCCompiler.cmake
index 4f355f3..d7f6f97 100644
--- a/Modules/CMakeDetermineCCompiler.cmake
+++ b/Modules/CMakeDetermineCCompiler.cmake
@@ -106,7 +106,7 @@ if(NOT CMAKE_C_COMPILER_ID_RUN)
   #      ...
   #      /path/to/cc ...CompilerIdC/...
   # to extract the compiler front-end for the language.
-  set(CMAKE_C_COMPILER_ID_TOOL_MATCH_REGEX "\nLd[^\n]*(\n[ \t]+[^\n]*)*\n[ \t]+([^ \t\r\n]+)[^\r\n]*-o[^\r\n]*CompilerIdC/(\\./)?(CompilerIdC.xctest/)?CompilerIdC[ \t\n\\\"]")
+  set(CMAKE_C_COMPILER_ID_TOOL_MATCH_REGEX "\nLd[^\n]*(\n[ \t]+[^\n]*)*\n[ \t]+([^ \t\r\n]+)[^\r\n]*-o[^\r\n]*CompilerIdC/(\\./)?(CompilerIdC.(framework|xctest)/)?CompilerIdC[ \t\n\\\"]")
   set(CMAKE_C_COMPILER_ID_TOOL_MATCH_INDEX 2)
 
   include(${CMAKE_ROOT}/Modules/CMakeDetermineCompilerId.cmake)
diff --git a/Modules/CMakeDetermineCXXCompiler.cmake b/Modules/CMakeDetermineCXXCompiler.cmake
index 96b4209..bd878b2 100644
--- a/Modules/CMakeDetermineCXXCompiler.cmake
+++ b/Modules/CMakeDetermineCXXCompiler.cmake
@@ -101,7 +101,7 @@ if(NOT CMAKE_CXX_COMPILER_ID_RUN)
   #      ...
   #      /path/to/cc ...CompilerIdCXX/...
   # to extract the compiler front-end for the language.
-  set(CMAKE_CXX_COMPILER_ID_TOOL_MATCH_REGEX "\nLd[^\n]*(\n[ \t]+[^\n]*)*\n[ \t]+([^ \t\r\n]+)[^\r\n]*-o[^\r\n]*CompilerIdCXX/(\\./)?(CompilerIdCXX.xctest/)?CompilerIdCXX[ \t\n\\\"]")
+  set(CMAKE_CXX_COMPILER_ID_TOOL_MATCH_REGEX "\nLd[^\n]*(\n[ \t]+[^\n]*)*\n[ \t]+([^ \t\r\n]+)[^\r\n]*-o[^\r\n]*CompilerIdCXX/(\\./)?(CompilerIdCXX.(framework|xctest)/)?CompilerIdCXX[ \t\n\\\"]")
   set(CMAKE_CXX_COMPILER_ID_TOOL_MATCH_INDEX 2)
 
   include(${CMAKE_ROOT}/Modules/CMakeDetermineCompilerId.cmake)
diff --git a/Modules/CMakeDetermineCompilerId.cmake b/Modules/CMakeDetermineCompilerId.cmake
index 2a0dbd3..a63d317 100644
--- a/Modules/CMakeDetermineCompilerId.cmake
+++ b/Modules/CMakeDetermineCompilerId.cmake
@@ -352,6 +352,8 @@ Id flags: ${testflags} ${CMAKE_${lang}_COMPILER_ID_FLAGS_ALWAYS}
       if(CMAKE_OSX_SYSROOT MATCHES "(^|/)[Ii][Pp][Hh][Oo][Nn][Ee]" OR
         CMAKE_OSX_SYSROOT MATCHES "(^|/)[Aa][Pp][Pp][Ll][Ee][Tt][Vv]")
         set(id_product_type "com.apple.product-type.bundle.unit-test")
+      elseif(CMAKE_OSX_SYSROOT MATCHES "(^|/)[Ww][Aa][Tt][Cc][Hh]")
+        set(id_product_type "com.apple.product-type.framework")
       endif()
     else()
       set(id_sdkroot "")
@@ -366,7 +368,7 @@ Id flags: ${testflags} ${CMAKE_${lang}_COMPILER_ID_FLAGS_ALWAYS}
       set(id_code_sign_identity
         "CODE_SIGN_IDENTITY = \"${CMAKE_XCODE_ATTRIBUTE_CODE_SIGN_IDENTITY}\";")
     else()
-      set(id_code_sign_identity "")
+      set(id_code_sign_identity "CODE_SIGN_IDENTITY = \"\";")
     endif()
     configure_file(${CMAKE_ROOT}/Modules/CompilerId/Xcode-3.pbxproj.in
       ${id_dir}/CompilerId${lang}.xcodeproj/project.pbxproj @ONLY)
@@ -491,6 +493,9 @@ ${CMAKE_${lang}_COMPILER_ID_OUTPUT}
 
       # com.apple.package-type.bundle.unit-test
       ${_glob_id_dir}/*.xctest/*
+
+      # com.apple.product-type.framework
+      ${_glob_id_dir}/*.framework/*
       )
     list(REMOVE_ITEM files "${src}")
     set(COMPILER_${lang}_PRODUCED_FILES "")
diff --git a/Modules/CMakeTestCCompiler.cmake b/Modules/CMakeTestCCompiler.cmake
index f74a1c6..7bf6fde 100644
--- a/Modules/CMakeTestCCompiler.cmake
+++ b/Modules/CMakeTestCCompiler.cmake
@@ -11,6 +11,12 @@ endif()
 
 include(CMakeTestCompilerCommon)
 
+# work around enforced code signing and / or missing exectuable target type
+set(__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE ${CMAKE_TRY_COMPILE_TARGET_TYPE})
+if(_CMAKE_FEATURE_DETECTION_TARGET_TYPE)
+  set(CMAKE_TRY_COMPILE_TARGET_TYPE ${_CMAKE_FEATURE_DETECTION_TARGET_TYPE})
+endif()
+
 # Remove any cached result from an older CMake version.
 # We now store this in CMakeCCompiler.cmake.
 unset(CMAKE_C_COMPILER_WORKS CACHE)
@@ -86,4 +92,6 @@ else()
   endif()
 endif()
 
+set(CMAKE_TRY_COMPILE_TARGET_TYPE ${__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE})
+unset(__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE)
 unset(__CMAKE_C_COMPILER_OUTPUT)
diff --git a/Modules/CMakeTestCXXCompiler.cmake b/Modules/CMakeTestCXXCompiler.cmake
index fe6bd25..7e595b7 100644
--- a/Modules/CMakeTestCXXCompiler.cmake
+++ b/Modules/CMakeTestCXXCompiler.cmake
@@ -11,6 +11,12 @@ endif()
 
 include(CMakeTestCompilerCommon)
 
+# work around enforced code signing and / or missing exectuable target type
+set(__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE ${CMAKE_TRY_COMPILE_TARGET_TYPE})
+if(_CMAKE_FEATURE_DETECTION_TARGET_TYPE)
+  set(CMAKE_TRY_COMPILE_TARGET_TYPE ${_CMAKE_FEATURE_DETECTION_TARGET_TYPE})
+endif()
+
 # Remove any cached result from an older CMake version.
 # We now store this in CMakeCXXCompiler.cmake.
 unset(CMAKE_CXX_COMPILER_WORKS CACHE)
@@ -79,4 +85,6 @@ else()
   endif()
 endif()
 
+set(CMAKE_TRY_COMPILE_TARGET_TYPE ${__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE})
+unset(__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE)
 unset(__CMAKE_CXX_COMPILER_OUTPUT)
diff --git a/Modules/Platform/Darwin-Initialize.cmake b/Modules/Platform/Darwin-Initialize.cmake
index 3db77aa..2d797f6 100644
--- a/Modules/Platform/Darwin-Initialize.cmake
+++ b/Modules/Platform/Darwin-Initialize.cmake
@@ -34,7 +34,7 @@ string(REGEX REPLACE "^([0-9]+\\.[0-9]+).*$" "\\1"
 # CMAKE_OSX_DEPLOYMENT_TARGET
 
 # Set cache variable - end user may change this during ccmake or cmake-gui configure.
-if(_CURRENT_OSX_VERSION VERSION_GREATER 10.3)
+if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND _CURRENT_OSX_VERSION VERSION_GREATER 10.3)
   set(CMAKE_OSX_DEPLOYMENT_TARGET "$ENV{MACOSX_DEPLOYMENT_TARGET}" CACHE STRING
     "Minimum OS X version to target for deployment (at runtime); newer APIs weak linked. Set to empty string for default value.")
 endif()
@@ -49,6 +49,12 @@ elseif(NOT "x$ENV{SDKROOT}" STREQUAL "x" AND
         (NOT "x$ENV{SDKROOT}" MATCHES "/" OR IS_DIRECTORY "$ENV{SDKROOT}"))
   # Use the value of SDKROOT from the environment.
   set(_CMAKE_OSX_SYSROOT_DEFAULT "$ENV{SDKROOT}")
+elseif(CMAKE_SYSTEM_NAME STREQUAL iOS)
+  set(_CMAKE_OSX_SYSROOT_DEFAULT "iphoneos")
+elseif(CMAKE_SYSTEM_NAME STREQUAL tvOS)
+  set(_CMAKE_OSX_SYSROOT_DEFAULT "appletvos")
+elseif(CMAKE_SYSTEM_NAME STREQUAL watchOS)
+  set(_CMAKE_OSX_SYSROOT_DEFAULT "watchos")
 elseif("${CMAKE_GENERATOR}" MATCHES Xcode
        OR CMAKE_OSX_DEPLOYMENT_TARGET
        OR CMAKE_OSX_ARCHITECTURES MATCHES "[^;]"
diff --git a/Modules/Platform/Darwin.cmake b/Modules/Platform/Darwin.cmake
index 727baa6..a73ffba 100644
--- a/Modules/Platform/Darwin.cmake
+++ b/Modules/Platform/Darwin.cmake
@@ -1,5 +1,13 @@
 set(APPLE 1)
 
+if(CMAKE_SYSTEM_NAME STREQUAL "iOS" OR CMAKE_SYSTEM_NAME STREQUAL "tvOS" OR CMAKE_SYSTEM_NAME STREQUAL "watchOS")
+  set(CMAKE_MACOSX_BUNDLE ON)
+
+  set(CMAKE_FIND_ROOT_PATH "${_CMAKE_OSX_SYSROOT_PATH}")
+  set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+  set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+endif()
+
 # Darwin versions:
 #   6.x == Mac OSX 10.2 (Jaguar)
 #   7.x == Mac OSX 10.3 (Panther)
diff --git a/Modules/Platform/iOS-Determine-CXX.cmake b/Modules/Platform/iOS-Determine-CXX.cmake
new file mode 100644
index 0000000..ac80fa6
--- /dev/null
+++ b/Modules/Platform/iOS-Determine-CXX.cmake
@@ -0,0 +1 @@
+include(Platform/Darwin-Determine-CXX)
diff --git a/Modules/Platform/iOS-Initialize.cmake b/Modules/Platform/iOS-Initialize.cmake
new file mode 100644
index 0000000..41399a3
--- /dev/null
+++ b/Modules/Platform/iOS-Initialize.cmake
@@ -0,0 +1,7 @@
+include(Platform/Darwin-Initialize)
+
+if(NOT _CMAKE_OSX_SYSROOT_PATH MATCHES "/iPhone(OS|Simulator)")
+  message(FATAL_ERROR "${CMAKE_OSX_SYSROOT} is not an iOS SDK")
+endif()
+
+set(_CMAKE_FEATURE_DETECTION_TARGET_TYPE STATIC_LIBRARY)
diff --git a/Modules/Platform/iOS.cmake b/Modules/Platform/iOS.cmake
new file mode 100644
index 0000000..850ddc2
--- /dev/null
+++ b/Modules/Platform/iOS.cmake
@@ -0,0 +1 @@
+include(Platform/Darwin)
diff --git a/Modules/Platform/tvOS-Determine-CXX.cmake b/Modules/Platform/tvOS-Determine-CXX.cmake
new file mode 100644
index 0000000..ac80fa6
--- /dev/null
+++ b/Modules/Platform/tvOS-Determine-CXX.cmake
@@ -0,0 +1 @@
+include(Platform/Darwin-Determine-CXX)
diff --git a/Modules/Platform/tvOS-Initialize.cmake b/Modules/Platform/tvOS-Initialize.cmake
new file mode 100644
index 0000000..6834c80
--- /dev/null
+++ b/Modules/Platform/tvOS-Initialize.cmake
@@ -0,0 +1,7 @@
+include(Platform/Darwin-Initialize)
+
+if(NOT _CMAKE_OSX_SYSROOT_PATH MATCHES "/AppleTV(OS|Simulator)")
+  message(FATAL_ERROR "${CMAKE_OSX_SYSROOT} is not an tvOS SDK")
+endif()
+
+set(_CMAKE_FEATURE_DETECTION_TARGET_TYPE STATIC_LIBRARY)
diff --git a/Modules/Platform/tvOS.cmake b/Modules/Platform/tvOS.cmake
new file mode 100644
index 0000000..850ddc2
--- /dev/null
+++ b/Modules/Platform/tvOS.cmake
@@ -0,0 +1 @@
+include(Platform/Darwin)
diff --git a/Modules/Platform/watchOS-Determine-CXX.cmake b/Modules/Platform/watchOS-Determine-CXX.cmake
new file mode 100644
index 0000000..ac80fa6
--- /dev/null
+++ b/Modules/Platform/watchOS-Determine-CXX.cmake
@@ -0,0 +1 @@
+include(Platform/Darwin-Determine-CXX)
diff --git a/Modules/Platform/watchOS-Initialize.cmake b/Modules/Platform/watchOS-Initialize.cmake
new file mode 100644
index 0000000..2f396d3
--- /dev/null
+++ b/Modules/Platform/watchOS-Initialize.cmake
@@ -0,0 +1,7 @@
+include(Platform/Darwin-Initialize)
+
+if(NOT _CMAKE_OSX_SYSROOT_PATH MATCHES "/Watch(OS|Simulator)")
+  message(FATAL_ERROR "${CMAKE_OSX_SYSROOT} is not an watchOS SDK")
+endif()
+
+set(_CMAKE_FEATURE_DETECTION_TARGET_TYPE STATIC_LIBRARY)
diff --git a/Modules/Platform/watchOS.cmake b/Modules/Platform/watchOS.cmake
new file mode 100644
index 0000000..850ddc2
--- /dev/null
+++ b/Modules/Platform/watchOS.cmake
@@ -0,0 +1 @@
+include(Platform/Darwin)