diff --git a/clang/cmake/caches/CrossWinToARMLinux.cmake b/clang/cmake/caches/CrossWinToARMLinux.cmake
--- a/clang/cmake/caches/CrossWinToARMLinux.cmake
+++ b/clang/cmake/caches/CrossWinToARMLinux.cmake
@@ -101,6 +101,7 @@
 set(COMPILER_RT_BUILD_LIBFUZZER             OFF CACHE BOOL "")
 set(COMPILER_RT_BUILD_PROFILE               OFF CACHE BOOL "")
 set(COMPILER_RT_BUILD_CRT                   OFF CACHE BOOL "")
+set(COMPILER_RT_BUILD_ORC                   OFF CACHE BOOL "")
 set(COMPILER_RT_DEFAULT_TARGET_ONLY         ON CACHE BOOL "")
 set(COMPILER_RT_INCLUDE_TESTS               ON CACHE BOOL "")
 
diff --git a/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake b/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake
--- a/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake
+++ b/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake
@@ -78,5 +78,5 @@
 set(ALL_SHADOWCALLSTACK_SUPPORTED_ARCH ${ARM64})
 
 if (UNIX)
-set(ALL_ORC_SUPPORTED_ARCH ${X86_64})
+set(ALL_ORC_SUPPORTED_ARCH ${X86_64} ${ARM64} ${ARM32})
 endif()
diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -480,6 +480,7 @@
           list(APPEND PROFILE_SUPPORTED_OS ${platform}sim)
           list(APPEND TSAN_SUPPORTED_OS ${platform}sim)
           list(APPEND FUZZER_SUPPORTED_OS ${platform}sim)
+          list(APPEND ORC_SUPPORTED_OS ${platform}sim)
         endif()
         foreach(arch ${DARWIN_${platform}sim_ARCHS})
           list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
@@ -510,6 +511,7 @@
             list(APPEND TSAN_SUPPORTED_OS ${platform})
           endif()
           list(APPEND FUZZER_SUPPORTED_OS ${platform})
+          list(APPEND ORC_SUPPORTED_OS ${platform})
         endif()
         foreach(arch ${DARWIN_${platform}_ARCHS})
           list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
diff --git a/compiler-rt/lib/orc/CMakeLists.txt b/compiler-rt/lib/orc/CMakeLists.txt
--- a/compiler-rt/lib/orc/CMakeLists.txt
+++ b/compiler-rt/lib/orc/CMakeLists.txt
@@ -10,8 +10,7 @@
   )
 
 # Implementation files for all ORC architectures.
-set(x86_64_SOURCES
-# x86-64 specific assembly files will go here.
+set(ALL_ORC_ASM_SOURCES
   macho_tlv.x86-64.S
   elfnix_tls.x86-64.S
 )
@@ -36,7 +35,7 @@
 # consumption by tests.
 set(ORC_ALL_SOURCE_FILES
   ${ORC_SOURCES}
-  ${x86_64_SOURCES}
+  ${ALL_ORC_ASM_SOURCES}
   ${ORC_IMPL_HEADERS}
   )
 
@@ -61,17 +60,16 @@
 endif()
 
 if (APPLE)
-   add_asm_sources(ORC_ASM_SOURCES macho_tlv.x86-64.S)
+  add_asm_sources(ORC_ASM_SOURCES macho_tlv.x86-64.S)
 
   add_compiler_rt_object_libraries(RTOrc
     OS ${ORC_SUPPORTED_OS}
     ARCHS ${ORC_SUPPORTED_ARCH}
-    SOURCES ${ORC_SOURCES} ${x86_64_SOURCES}
+    SOURCES ${ORC_SOURCES} ${ORC_ASM_SOURCES}
     ADDITIONAL_HEADERS ${ORC_IMPL_HEADERS}
     CFLAGS ${ORC_CFLAGS}
     DEPS ${ORC_DEPS})
 
-  # We only support running on osx for now.
   add_compiler_rt_runtime(clang_rt.orc
     STATIC
     OS ${ORC_SUPPORTED_OS}
@@ -82,13 +80,16 @@
     LINK_LIBS ${ORC_LINK_LIBS}
     PARENT_TARGET orc)
 else() # not Apple
+  add_asm_sources(ORC_ASM_SOURCES elfnix_tls.x86-64.S)
+
   foreach(arch ${ORC_SUPPORTED_ARCH})
     if(NOT CAN_TARGET_${arch})
       continue()
     endif()
+
     add_compiler_rt_object_libraries(RTOrc
       ARCHS ${arch}
-      SOURCES ${ORC_SOURCES} ${${arch}_SOURCES}
+      SOURCES ${ORC_SOURCES} ${ORC_ASM_SOURCES}
       ADDITIONAL_HEADERS ${ORC_IMPL_HEADERS}
       CFLAGS ${ORC_CFLAGS}
       DEPS ${ORC_DEPS})
diff --git a/compiler-rt/lib/orc/elfnix_tls.x86-64.S b/compiler-rt/lib/orc/elfnix_tls.x86-64.S
--- a/compiler-rt/lib/orc/elfnix_tls.x86-64.S
+++ b/compiler-rt/lib/orc/elfnix_tls.x86-64.S
@@ -11,6 +11,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// The content of this file is x86_64-only
+#if defined(__x86_64__)
+
 #define REGISTER_SAVE_SPACE_SIZE        512
 
         .text
@@ -57,3 +60,5 @@
         addq            $REGISTER_SAVE_SPACE_SIZE, %rsp
         popq            %rbp
         ret
+
+#endif // defined(__x86_64__)
diff --git a/compiler-rt/lib/orc/macho_tlv.x86-64.S b/compiler-rt/lib/orc/macho_tlv.x86-64.S
--- a/compiler-rt/lib/orc/macho_tlv.x86-64.S
+++ b/compiler-rt/lib/orc/macho_tlv.x86-64.S
@@ -10,6 +10,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// The content of this file is x86_64-only
+#if defined(__x86_64__)
+
 #define REGISTER_SAVE_SPACE_SIZE        512
 
         .text
@@ -66,3 +69,5 @@
         addq            $REGISTER_SAVE_SPACE_SIZE, %rsp
         popq            %rbp
         ret
+
+#endif // defined(__x86_64__)
diff --git a/compiler-rt/lib/orc/simple_packed_serialization.h b/compiler-rt/lib/orc/simple_packed_serialization.h
--- a/compiler-rt/lib/orc/simple_packed_serialization.h
+++ b/compiler-rt/lib/orc/simple_packed_serialization.h
@@ -396,10 +396,12 @@
     uint64_t Size;
     if (!SPSArgList<uint64_t>::deserialize(IB, Size))
       return false;
+    if (Size > std::numeric_limits<size_t>::max())
+      return false;
     Data = IB.data();
     if (!IB.skip(Size))
       return false;
-    S = {Data, Size};
+    S = {Data, static_cast<size_t>(Size)};
     return true;
   }
 };