cmake: linker: separate toolchain_ld_options() calls for grouped flags

Fixes #91045

Adding NO_SPLIT in the TOOLCHAIN_LD_FLAGS list caused every flags in the
list to be checked together by the linker. This caused issues where
incompatible flags was passed together, and the result was that none was
propagated to the linker.

By using separate variables, we can achieve the initial goal of NO_SPLIT to
only group a sub-set of flags.

Signed-off-by: Pierrick Guillaume <[email protected]>

Author: Fymyte

CMakeLists.txt

@@ -474,6 +474,16 @@ if(DEFINED TOOLCHAIN_LD_FLAGS)
   zephyr_ld_options(${TOOLCHAIN_LD_FLAGS})
 endif()
 
+foreach(GROUPED_FLAGS IN LISTS TOOLCHAIN_GROUPED_LD_FLAGS)
+  if(DEFINED ${GROUPED_FLAGS})
+    zephyr_ld_options(NO_SPLIT ${${GROUPED_FLAGS}})
+  else()
+    message(FATAL_ERROR "Variable '${GROUPED_FLAGS}' is not defined, "
+      "please ensure the variable is defined and points to valid linker flags. "
+      "If '${GROUPED_FLAGS}' is a linker flags itself, then it must be placed in a list")
+  endif()
+endforeach()
+
 zephyr_link_libraries(PROPERTY base)
 
 zephyr_link_libraries_ifndef(CONFIG_LINKER_USE_RELAX PROPERTY no_relax)

cmake/compiler/clang/target_arm.cmake

@@ -39,4 +39,4 @@ if(CONFIG_FP16)
   endif()
 endif()
 list(APPEND TOOLCHAIN_C_FLAGS ${ARM_C_FLAGS})
-list(APPEND TOOLCHAIN_LD_FLAGS NO_SPLIT ${ARM_C_FLAGS})
+list(APPEND TOOLCHAIN_GROUPED_LD_FLAGS ARM_C_FLAGS)

cmake/compiler/gcc/target_arm.cmake

@@ -45,7 +45,7 @@ if(CONFIG_THREAD_LOCAL_STORAGE)
 endif()
 
 list(APPEND TOOLCHAIN_C_FLAGS ${ARM_C_FLAGS})
-list(APPEND TOOLCHAIN_LD_FLAGS NO_SPLIT ${ARM_C_FLAGS})
+list(APPEND TOOLCHAIN_GROUPED_LD_FLAGS ARM_C_FLAGS)
 
 # Flags not supported by llext linker
 # (regexps are supported and match whole word)

cmake/compiler/gcc/target_riscv.cmake

@@ -129,17 +129,13 @@ if(NOT CONFIG_RISCV_ISA_EXT_M AND
   string(CONCAT riscv_march ${riscv_march} "_zmmul")
 endif()
 
-list(APPEND TOOLCHAIN_C_FLAGS
-     -mabi=${riscv_mabi}
-     -march=${riscv_march}
-     -mcmodel=${riscv_mcmodel}
-     )
-
-list(APPEND TOOLCHAIN_LD_FLAGS NO_SPLIT
+list(APPEND RISCV_C_FLAGS
      -mabi=${riscv_mabi}
      -march=${riscv_march}
      -mcmodel=${riscv_mcmodel}
      )
+list(APPEND TOOLCHAIN_C_FLAGS ${RISCV_C_FLAGS})
+list(APPEND TOOLCHAIN_GROUPED_LD_FLAGS RISCV_C_FLAGS)
 
 # Flags not supported by llext linker
 # (regexps are supported and match whole word)