[CMake] Include riscv32-unknown-elf runtimes in Fuchsia toolchain (#76849)

This contains compiler-rt builtins and llvm-libc for baremetal use.

Differential Revision: https://reviews.llvm.org/D155337

Author: petrhosek

clang/cmake/caches/Fuchsia-stage2.cmake

@@ -6,7 +6,7 @@ set(LLVM_TARGETS_TO_BUILD X86;ARM;AArch64;RISCV CACHE STRING "")
 
 set(PACKAGE_VENDOR Fuchsia CACHE STRING "")
 
-set(_FUCHSIA_ENABLE_PROJECTS "bolt;clang;clang-tools-extra;lld;llvm;polly")
+set(_FUCHSIA_ENABLE_PROJECTS "bolt;clang;clang-tools-extra;libc;lld;llvm;polly")
 set(LLVM_ENABLE_RUNTIMES "compiler-rt;libcxx;libcxxabi;libunwind" CACHE STRING "")
 
 set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")
@@ -22,8 +22,11 @@ set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_UNWIND_TABLES OFF CACHE BOOL "")
 set(LLVM_ENABLE_Z3_SOLVER OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB ON CACHE BOOL "")
+set(LLVM_FORCE_BUILD_RUNTIME ON CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
+set(LLVM_LIBC_FULL_BUILD ON CACHE BOOL "")
+set(LIBC_HDRGEN_ONLY ON CACHE BOOL "")
 set(LLVM_STATIC_LINK_CXX_STDLIB ON CACHE BOOL "")
 set(LLVM_USE_RELATIVE_PATHS_IN_FILES ON CACHE BOOL "")
 set(LLDB_ENABLE_CURSES OFF CACHE BOOL "")
@@ -297,6 +300,39 @@ if(FUCHSIA_SDK)
   set(LLVM_RUNTIME_MULTILIB_hwasan+noexcept_TARGETS "aarch64-unknown-fuchsia;riscv64-unknown-fuchsia" CACHE STRING "")
 endif()
 
+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_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} -march=rv32imafc -mabi=ilp32f" 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 RISCV CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_SYSROOT "" CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY CACHE STRING "")
+  foreach(lang C;CXX;ASM)
+    set(RUNTIMES_${target}_CMAKE_${lang}_FLAGS "--target=${target} -march=rv32imafc -mabi=ilp32f" 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_${target}_LLVM_ENABLE_RUNTIMES "libc" CACHE STRING "")
+endforeach()
+
 set(LLVM_BUILTIN_TARGETS "${BUILTIN_TARGETS}" CACHE STRING "")
 set(LLVM_RUNTIME_TARGETS "${RUNTIME_TARGETS}" CACHE STRING "")