[BOLT][Instrumentation] AArch64 instrumentation support in runtime

This commit adds support for AArch64 in instrumentation runtime library,
including AArch64 system calls.
Also this commit divides syscalls into target-specific files.

Reviewed By: rafauler, yota9

Differential Revision: https://reviews.llvm.org/D151942

Author: ElvinaYakubova

bolt/CMakeLists.txt

@@ -32,10 +32,10 @@ foreach (tgt ${BOLT_TARGETS_TO_BUILD})
 endforeach()
 
 set(BOLT_ENABLE_RUNTIME_default OFF)
-if (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64"
+if ((CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64"
+    OR CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64")
     AND (CMAKE_SYSTEM_NAME STREQUAL "Linux"
-      OR CMAKE_SYSTEM_NAME STREQUAL "Darwin")
-    AND "X86" IN_LIST BOLT_TARGETS_TO_BUILD)
+      OR CMAKE_SYSTEM_NAME STREQUAL "Darwin"))
   set(BOLT_ENABLE_RUNTIME_default ON)
 endif()
 option(BOLT_ENABLE_RUNTIME "Enable BOLT runtime" ${BOLT_ENABLE_RUNTIME_default})

bolt/runtime/CMakeLists.txt

@@ -27,8 +27,11 @@ set(BOLT_RT_FLAGS
   -fno-exceptions
   -fno-rtti
   -fno-stack-protector
-  -mno-sse
-  -fPIC)
+  -fPIC
+  -mgeneral-regs-only)
+if (CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64")
+  set(BOLT_RT_FLAGS ${BOLT_RT_FLAGS} "-mno-sse")
+endif()
 
 # Don't let the compiler think it can create calls to standard libs
 target_compile_options(bolt_rt_instr PRIVATE ${BOLT_RT_FLAGS})
@@ -39,7 +42,7 @@ target_include_directories(bolt_rt_hugify PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
 install(TARGETS bolt_rt_instr DESTINATION "lib${LLVM_LIBDIR_SUFFIX}")
 install(TARGETS bolt_rt_hugify DESTINATION "lib${LLVM_LIBDIR_SUFFIX}")
 
-if (CMAKE_CXX_COMPILER_ID MATCHES ".*Clang.*")
+if (CMAKE_CXX_COMPILER_ID MATCHES ".*Clang.*" AND CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   add_library(bolt_rt_instr_osx STATIC
     instr.cpp
     ${CMAKE_CURRENT_BINARY_DIR}/config.h