CMake: add support for Intel's LLVM-based compiler

This includes a few cleanups to our .cmake files where it was easier to
combine existing sections of Clang / AppleClang that no longer needed to
be distinct.

icpx could be replaced with a shell script:
 exec `basename $0`/clang++ --intel "$@"

tst_qnumeric is not passing
FAIL!  : tst_QNumeric::classifyF() Compared values are not the same
   Actual   (qFpClassify(tiny / two)): 2
   Expected (FP_SUBNORMAL)           : 3
   Loc: [/home/tjmaciei/src/qt/qt6-icx/qtbase/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp(344)]
FAIL!  : tst_QNumeric::classifyD() Compared values are not the same
   Actual   (qFpClassify(tiny / two)): 2
   Expected (FP_SUBNORMAL)           : 3
   Loc: [/home/tjmaciei/src/qt/qt6-icx/qtbase/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp(344)]
FAIL!  : tst_QNumeric::floatDistance(denormal) Compared values are not the same
   Actual   (qFloatDistance(from, stop)): 0
   Expected (expectedDistance)          : 4194304
   Loc: [/home/tjmaciei/src/qt/qt6-icx/qtbase/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp(408)]
FAIL!  : tst_QNumeric::doubleDistance(denormal) Compared values are not the same
   Actual   (qFloatDistance(from, stop)): 0
   Expected (expectedDistance)          : 2251799813685248
   Loc: [/home/tjmaciei/src/qt/qt6-icx/qtbase/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp(408)]
P

Change-Id: Icb2516126f674e7b8bb3fffd16ad59431e8c3379
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

6 files changed, 13 insertions, 25 deletions

diff --git a/cmake/QtBuildInformation.cmake b/cmake/QtBuildInformation.cmake
index e09f64e958..81daae5f13 100644
--- a/cmake/QtBuildInformation.cmake
+++ b/cmake/QtBuildInformation.cmake
@@ -292,6 +292,8 @@ function(qt_configure_process_add_summary_build_type_and_config)
     set(message "Compiler: ")
     if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
         string(APPEND message "clang (Apple)")
+    elseif(CMAKE_CXX_COMPILER_ID STREQUAL "IntelLLVM")
+        string(APPEND message "clang (Intel LLVM)")
     elseif(CLANG)
         string(APPEND message "clang")
     elseif(ICC)
diff --git a/cmake/QtFlagHandlingHelpers.cmake b/cmake/QtFlagHandlingHelpers.cmake
index dc81a79333..11d6a3933e 100644
--- a/cmake/QtFlagHandlingHelpers.cmake
+++ b/cmake/QtFlagHandlingHelpers.cmake
@@ -153,9 +153,7 @@ function(qt_internal_set_exceptions_flags target exceptions_on)
         set(_defs "QT_NO_EXCEPTIONS")
         if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
             set(_flag "/wd4530" "/wd4577")
-        elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
-            set(_flag "-fno-exceptions")
-        elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
+        elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU|AppleClang|InteLLLVM")
             set(_flag "-fno-exceptions")
         elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
             if (MSVC)
diff --git a/cmake/QtHeadersClean.cmake b/cmake/QtHeadersClean.cmake
index 7f54926f1a..f2596b4733 100644
--- a/cmake/QtHeadersClean.cmake
+++ b/cmake/QtHeadersClean.cmake
@@ -97,7 +97,7 @@ function(qt_internal_add_headers_clean_target
         "$<${compile_flags_exist_genex}:$<JOIN:${target_compile_flags_genex},;>>")
 
     if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU"
-            OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang"
+            OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang|IntelLLVM"
             OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
         # Turn on some extra warnings not found in -Wall -Wextra.
 
diff --git a/cmake/QtInternalTargets.cmake b/cmake/QtInternalTargets.cmake
index 7cc340d381..7bfa77d2b8 100644
--- a/cmake/QtInternalTargets.cmake
+++ b/cmake/QtInternalTargets.cmake
@@ -1,17 +1,8 @@
 
 function(qt_internal_set_warnings_are_errors_flags target)
     set(flags "")
-    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND NOT MSVC)
-        # Regular clang 3.0+
-        if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "3.0.0")
-            list(APPEND flags -Werror -Wno-error=\#warnings -Wno-error=deprecated-declarations)
-        endif()
-    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
-        # using AppleClang
-        # Apple clang 4.0+
-        if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "4.0.0" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS_EQUAL "9.2")
-            list(APPEND flags -Werror -Wno-error=\#warnings -Wno-error=deprecated-declarations)
-        endif()
+    if (CLANG AND NOT MSVC)
+        list(APPEND flags -Werror -Wno-error=\#warnings -Wno-error=deprecated-declarations)
     elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
         # using GCC
         list(APPEND flags -Werror -Wno-error=cpp -Wno-error=deprecated-declarations)
@@ -297,15 +288,7 @@ qt_auto_detect_implicit_sse2()
 function(qt_auto_detect_fpmath)
     # fpmath configuration adjustment in qt_module.prf
     set(fpmath_supported FALSE)
-    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-        if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "3.4")
-            set(fpmath_supported TRUE)
-        endif()
-    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
-        if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "5.1")
-            set(fpmath_supported TRUE)
-        endif()
-    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+    if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang|GNU|IntelLLVM")
         set(fpmath_supported TRUE)
     endif()
     if(fpmath_supported AND TEST_architecture_arch STREQUAL "i386" AND __implicit_sse2_for_qt_modules_enabled)
diff --git a/cmake/QtPlatformSupport.cmake b/cmake/QtPlatformSupport.cmake
index e4c8ca123b..e4a33ab46f 100644
--- a/cmake/QtPlatformSupport.cmake
+++ b/cmake/QtPlatformSupport.cmake
@@ -30,9 +30,10 @@ qt_set01(UIKIT APPLE AND (IOS OR TVOS OR WATCHOS))
 qt_set01(MACOS APPLE AND NOT UIKIT)
 
 qt_set01(GCC CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-qt_set01(CLANG CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+qt_set01(CLANG CMAKE_CXX_COMPILER_ID MATCHES "Clang|IntelLLVM")
 qt_set01(APPLECLANG CMAKE_CXX_COMPILER_ID MATCHES "AppleClang")
 qt_set01(ICC CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
+qt_set01(IntelLLVM CMAKE_CXX_COMPILER_ID STREQUAL "IntelLLVM")
 qt_set01(QCC CMAKE_CXX_COMPILER_ID STREQUAL "QCC") # CMP0047
 
 if(CMAKE_SIZEOF_VOID_P EQUAL 8)
diff --git a/cmake/QtPriHelpers.cmake b/cmake/QtPriHelpers.cmake
index 85767fadbe..ba7322ad03 100644
--- a/cmake/QtPriHelpers.cmake
+++ b/cmake/QtPriHelpers.cmake
@@ -712,6 +712,10 @@ QT_PATCH_VERSION = ${PROJECT_VERSION_PATCH}
         set(compiler_version_major_var_name "QT_APPLE_CLANG_MAJOR_VERSION")
         set(compiler_version_minor_var_name "QT_APPLE_CLANG_MINOR_VERSION")
         set(compiler_version_patch_var_name "QT_APPLE_CLANG_PATCH_VERSION")
+    elseif(IntelLLVM)
+        set(compiler_version_major_var_name "QT_INTELLLVM_MAJOR_VERSION")
+        set(compiler_version_minor_var_name "QT_INTELLLVM_MINOR_VERSION")
+        set(compiler_version_patch_var_name "QT_INTELLLVM_PATCH_VERSION")
     elseif(CLANG)
         set(compiler_version_major_var_name "QT_CLANG_MAJOR_VERSION")
         set(compiler_version_minor_var_name "QT_CLANG_MINOR_VERSION")