Merge branch 'PHP-8.3' into PHP-8.4

Author: petk

cmake/cmake/Bootstrap.cmake

@@ -27,8 +27,8 @@ if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.29)
   endif()
 endif()
 
-# Check whether to enable interprocedural optimization.
-include(PHP/InterproceduralOptimization)
+# Check whether IPO/LTO can be enabled.
+include(PHP/Optimization)
 
 # Set CMAKE_POSITION_INDEPENDENT_CODE.
 include(PHP/PositionIndependentCode)

cmake/cmake/modules/PHP/InterproceduralOptimization.cmake

@@ -0,0 +1,76 @@
+#[=============================================================================[
+# PHP/Optimization
+
+Enable interprocedural optimization (IPO/LTO) on all targets, if supported.
+
+This adds linker flag `-flto` if it is supported by the compiler to run standard
+link-time optimizer.
+
+It can be also controlled more granular with the
+`CMAKE_INTERPROCEDURAL_OPTIMIZATION_<CONFIG>` variables based on the build type.
+
+This module also checks whether IPO/LTO can be enabled based on the PHP
+configuration (due to global register variables) and compiler/platform.
+
+https://cmake.org/cmake/help/latest/prop_tgt/INTERPROCEDURAL_OPTIMIZATION.html
+#]=============================================================================]
+
+include_guard(GLOBAL)
+
+# TODO: Recheck Clang errors as OBJECT libraries doesn't seem to work.
+# TODO: Recheck and add PHP_LTO option to docs.
+
+option(PHP_LTO "Build PHP with link time optimization (LTO) if supported")
+mark_as_advanced(PHP_LTO)
+
+block(PROPAGATE CMAKE_INTERPROCEDURAL_OPTIMIZATION)
+  set(enableIpo ${PHP_LTO})
+  set(reason "")
+
+  if(NOT PHP_LTO)
+    set(enableIpo FALSE)
+    # Disabled.
+  elseif(
+    CMAKE_C_COMPILER_ID STREQUAL "GNU"
+    AND (
+      NOT DEFINED ZEND_GLOBAL_REGISTER_VARIABLES
+      OR ZEND_GLOBAL_REGISTER_VARIABLES
+    )
+  )
+    # Zend/zend_execute.c uses global register variables and IPO is for now
+    # disabled when using GNU C compiler due to a bug:
+    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68384
+    set(reason "GCC global register variables")
+    set(enableIpo FALSE)
+  elseif(CMAKE_C_COMPILER_ID STREQUAL "AppleClang")
+    # See: https://gitlab.kitware.com/cmake/cmake/-/issues/25202
+    set(reason "AppleClang")
+    set(enableIpo FALSE)
+  elseif(CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_SIZEOF_VOID_P EQUAL 4)
+    # On 32-bit Linux machine, this produced undefined references linker errors.
+    set(reason "Clang on 32-bit")
+    set(enableIpo FALSE)
+  endif()
+
+  if(enableIpo)
+    include(CheckIPOSupported)
+    check_ipo_supported(RESULT supported OUTPUT reason)
+    if(NOT supported)
+      set(enableIpo FALSE)
+      if(NOT reason)
+        set(reason "unsupported")
+      endif()
+    endif()
+  endif()
+
+  if(enableIpo)
+    message(STATUS "Interprocedural optimization (IPO/LTO) enabled")
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
+  else()
+    if(reason)
+      set(reason " (${reason})")
+    endif()
+    message(STATUS "Interprocedural optimization (IPO/LTO) disabled${reason}")
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION FALSE)
+  endif()
+endblock()