[clang] [Fuchsia] Include baremetal ARM builtins and libc (PR #83949)

[Petr Hosek via cfe-commits]

https://github.com/petrhosek created https://github.com/llvm/llvm-project/pull/83949

For now we only include the armv6m-unknown-eabi target but we plan to include more targets in the future (including multilibs).

>From 7924ab437a5df81aa5d5481541ad4979335f5a9b Mon Sep 17 00:00:00 2001
From: Petr Hosek <phosek at google.com>
Date: Mon, 6 Mar 2023 19:31:13 +0000
Subject: [PATCH] [Fuchsia] Include baremetal ARM builtins and libc

For now we only include the armv6m-unknown-eabi target but we plan to
include more targets in the future (including multilibs).
---
 clang/cmake/caches/Fuchsia-stage2.cmake | 37 +++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/clang/cmake/caches/Fuchsia-stage2.cmake b/clang/cmake/caches/Fuchsia-stage2.cmake
index eee37c5e7901fa..97c93969e18e80 100644
--- a/clang/cmake/caches/Fuchsia-stage2.cmake
+++ b/clang/cmake/caches/Fuchsia-stage2.cmake
@@ -300,10 +300,43 @@ if(FUCHSIA_SDK)
   set(LLVM_RUNTIME_MULTILIB_hwasan+noexcept_TARGETS "aarch64-unknown-fuchsia;riscv64-unknown-fuchsia" CACHE STRING "")
 endif()
 
+foreach(target armv6m-unknown-eabi)
+  list(APPEND BUILTIN_TARGETS "${target}")
+  set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Generic CACHE STRING "")
+  set(BUILTINS_${target}_CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
+  set(BUILTINS_${target}_CMAKE_SYSROOT "" CACHE STRING "")
+  set(BUILTINS_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+  foreach(lang C;CXX;ASM)
+    set(BUILTINS_${target}_CMAKE_${lang}_FLAGS "--target=${target} -mcpu=cortex-m0plus -mthumb" CACHE STRING "")
+  endforeach()
+  foreach(type SHARED;MODULE;EXE)
+    set(BUILTINS_${target}_CMAKE_${type}_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
+  endforeach()
+  set(BUILTINS_${target}_COMPILER_RT_BAREMETAL_BUILD ON CACHE BOOL "")
+
+  list(APPEND RUNTIME_TARGETS "${target}")
+  set(RUNTIMES_${target}_CMAKE_SYSTEM_NAME Generic CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_SYSROOT "" CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY CACHE STRING "")
+  foreach(lang C;CXX;ASM)
+    set(RUNTIMES_${target}_CMAKE_${lang}_FLAGS "--target=${target} -mcpu=cortex-m0plus -mthumb" CACHE STRING "")
+  endforeach()
+  foreach(type SHARED;MODULE;EXE)
+    set(RUNTIMES_${target}_CMAKE_${type}_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
+  endforeach()
+  set(RUNTIMES_${target}_LLVM_LIBC_FULL_BUILD ON CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBC_ENABLE_USE_BY_CLANG ON CACHE BOOL "")
+  set(RUNTIMES_${target}_LLVM_INCLUDE_TESTS OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LLVM_ENABLE_ASSERTIONS OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LLVM_ENABLE_RUNTIMES "libc" CACHE STRING "")
+endforeach()
+
 foreach(target riscv32-unknown-elf)
   list(APPEND BUILTIN_TARGETS "${target}")
   set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Generic CACHE STRING "")
-  set(BUILTINS_${target}_CMAKE_SYSTEM_PROCESSOR RISCV CACHE STRING "")
+  set(BUILTINS_${target}_CMAKE_SYSTEM_PROCESSOR riscv CACHE STRING "")
   set(BUILTINS_${target}_CMAKE_SYSROOT "" CACHE STRING "")
   set(BUILTINS_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
   foreach(lang C;CXX;ASM)
@@ -316,7 +349,7 @@ foreach(target riscv32-unknown-elf)
 
   list(APPEND RUNTIME_TARGETS "${target}")
   set(RUNTIMES_${target}_CMAKE_SYSTEM_NAME Generic CACHE STRING "")
-  set(RUNTIMES_${target}_CMAKE_SYSTEM_PROCESSOR RISCV CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_SYSTEM_PROCESSOR riscv CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_SYSROOT "" CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY CACHE STRING "")