[Mlir-commits] [mlir] [mlir][ArmSME] Make use of backend function attributes for enabling ZA storage (PR #71044)

[Benjamin Maxwell]

================
@@ -177,6 +178,39 @@ if(LLVM_ENABLE_PIC)
     target_link_options(mlir_async_runtime PRIVATE "-Wl,-exclude-libs,ALL")
   endif()
 
+  if (MLIR_RUN_ARM_SME_TESTS)
+    if (NOT DEFINED LLVM_MAIN_SRC_DIR)
+      message(FATAL_ERROR "LLVM_MAIN_SRC_DIR must be provided to build the ArmSME runtime.")
+    endif()
+
+    if (NOT DEFINED MLIR_ARM_SME__CAN_ASSEMBLE_ARM_SME)
+      # This should work on an AArch64 host with a recent version of clang.
+      file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/has_arm_sme_check.S
+      ".arch armv9-a+sme
+      .global main
+      .type   main, %function
+      main: smstart
+      .size   main, .-main")
+      try_compile(MLIR_ARM_SME__CAN_ASSEMBLE_ARM_SME ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR}/has_arm_sme_check.S)
+    endif()
+
+    if (NOT MLIR_ARM_SME__CAN_ASSEMBLE_ARM_SME)
+      message(FATAL_ERROR "Host compiler must be able to assemble AArch64 SME instructions to build the ArmSME runtime.")
+    endif()
+
+    # FIXME: This is very far from ideal, but enabling compiler-rt in the main
----------------
MacDue wrote:

I think these libraries are intended to be linked into your binary by clang, so in that case it makes sense for them to be static. There is an option to build parts into a shared library, for example:
```
option(COMPILER_RT_BUILD_STANDALONE_LIBATOMIC
  "Build standalone shared atomic library."
  OFF)
```
Which is what gave me the idea for the `COMPILER_RT_BUILD_STANDALONE_AARCH64_SME_RUNTIME` option. 


https://github.com/llvm/llvm-project/pull/71044