diff --git a/bolt/CMakeLists.txt b/bolt/CMakeLists.txt
index f43539b8e475..eb2a17738388 100644
--- a/bolt/CMakeLists.txt
+++ b/bolt/CMakeLists.txt
@@ -4,29 +4,55 @@ set(BOLT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(BOLT_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 set(CMAKE_CXX_STANDARD 14)
 
-ExternalProject_Add(bolt_rt
-  SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/runtime"
-  STAMP_DIR ${CMAKE_CURRENT_BINARY_DIR}/bolt_rt-stamps
-  BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/bolt_rt-bins
-  CMAKE_ARGS -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
-             -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
-             -DCMAKE_BUILD_TYPE=Release
-             -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
-             -DCMAKE_INSTALL_PREFIX=${LLVM_BINARY_DIR}
-  # You might want to set this to True if actively developing bolt_rt, otherwise
-  # cmake will not rebuild it after source code changes
-  BUILD_ALWAYS True
-  )
+if (NOT CMAKE_HOST_SYSTEM_NAME MATCHES Linux)
+  message(WARNING "Not building BOLT on unsupported platform")
+else()
+  set(BOLT_ENABLE_RUNTIME OFF)
+  if (CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "x86_64")
+    set(BOLT_ENABLE_RUNTIME ON)
+  endif()
 
-include_directories( ${BOLT_SOURCE_DIR}/include )
+  set(BOLT_INCLUDE_TESTS OFF)
+  if (LLVM_INCLUDE_TESTS)
+    string(FIND "${LLVM_ENABLE_PROJECTS}" "clang" POSITION)
+    if (NOT ${POSITION} EQUAL -1)
+      string(FIND "${LLVM_ENABLE_PROJECTS}" "lld" POSITION)
+      if (NOT ${POSITION} EQUAL -1)
+        set(BOLT_INCLUDE_TESTS ON)
+      else()
+        message(WARNING "Not including BOLT tests since lld is disabled")
+      endif()
+    else()
+      message(WARNING "Not including BOLT tests since clang is disabled")
+    endif()
+  endif()
 
-install(CODE "execute_process\(COMMAND \${CMAKE_COMMAND} -DCMAKE_INSTALL_PREFIX=\${CMAKE_INSTALL_PREFIX} -P ${CMAKE_CURRENT_BINARY_DIR}/bolt_rt-bins/cmake_install.cmake \)"
-  COMPONENT bolt_rt)
+  if (BOLT_ENABLE_RUNTIME)
+    message(STATUS "Building BOLT runtime libraries for X86")
+    ExternalProject_Add(bolt_rt
+      SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/runtime"
+      STAMP_DIR ${CMAKE_CURRENT_BINARY_DIR}/bolt_rt-stamps
+      BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/bolt_rt-bins
+      CMAKE_ARGS -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
+                 -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
+                 -DCMAKE_BUILD_TYPE=Release
+                 -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
+                 -DCMAKE_INSTALL_PREFIX=${LLVM_BINARY_DIR}
+      BUILD_ALWAYS True
+      )
+    install(CODE "execute_process\(COMMAND \${CMAKE_COMMAND} -DCMAKE_INSTALL_PREFIX=\${CMAKE_INSTALL_PREFIX} -P ${CMAKE_CURRENT_BINARY_DIR}/bolt_rt-bins/cmake_install.cmake \)"
+      COMPONENT bolt_rt)
+    add_llvm_install_targets(install-bolt_rt
+      DEPENDS bolt_rt
+      COMPONENT bolt_rt)
+  endif()
 
-add_llvm_install_targets(install-bolt_rt
-  DEPENDS bolt_rt
-  COMPONENT bolt_rt)
+  include_directories( ${BOLT_SOURCE_DIR}/include )
 
-add_subdirectory(lib)
-add_subdirectory(test)
-add_subdirectory(tools)
+  add_subdirectory(lib)
+  add_subdirectory(tools)
+
+  if (BOLT_INCLUDE_TESTS)
+    add_subdirectory(test)
+  endif()
+endif()
diff --git a/bolt/lib/Target/CMakeLists.txt b/bolt/lib/Target/CMakeLists.txt
index d929366e7fd2..c939193b720a 100644
--- a/bolt/lib/Target/CMakeLists.txt
+++ b/bolt/lib/Target/CMakeLists.txt
@@ -1,4 +1,11 @@
-foreach(t ${LLVM_TARGETS_TO_BUILD})
-  message(STATUS "Targeting llvm-bolt ${t}")
-  add_subdirectory(${t})
-endforeach()
+string(FIND "${LLVM_TARGETS_TO_BUILD}" "X86" POSITION)
+if (NOT ${POSITION} EQUAL -1)
+  message(STATUS "Targeting X86 in llvm-bolt")
+  add_subdirectory(X86)
+endif()
+
+string(FIND "${LLVM_TARGETS_TO_BUILD}" "AArch64" POSITION)
+if (NOT ${POSITION} EQUAL -1)
+  message(STATUS "Targeting AArch64 in llvm-bolt")
+  add_subdirectory(AArch64)
+endif()
diff --git a/bolt/test/CMakeLists.txt b/bolt/test/CMakeLists.txt
index 120ed869f6ab..2d788e3f1fc8 100644
--- a/bolt/test/CMakeLists.txt
+++ b/bolt/test/CMakeLists.txt
@@ -1,3 +1,7 @@
+llvm_canonicalize_cmake_booleans(
+  BOLT_ENABLE_RUNTIME
+  )
+
 configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
   ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg.py
diff --git a/bolt/test/X86/internal_call_instrument.s b/bolt/test/X86/internal_call_instrument.s
index 5ef49ae88c59..9915049210f3 100644
--- a/bolt/test/X86/internal_call_instrument.s
+++ b/bolt/test/X86/internal_call_instrument.s
@@ -1,6 +1,6 @@
 # This reproduces a bug with instrumentation crashes on internal call
 
-# REQUIRES: system-linux
+# REQUIRES: system-linux,bolt-runtime
 
 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s -o %t.o
 # Delete our BB symbols so BOLT doesn't mark them as entry points
diff --git a/bolt/test/lit.cfg.py b/bolt/test/lit.cfg.py
index 80a0546295ce..87413a1bb2fe 100644
--- a/bolt/test/lit.cfg.py
+++ b/bolt/test/lit.cfg.py
@@ -50,6 +50,9 @@ else:
     lit_config.warning('Setting a timeout per test not supported. ' + errormsg
                        + ' Some tests will be skipped.')
 
+if config.bolt_enable_runtime:
+    config.available_features.add("bolt-runtime")
+
 llvm_config.use_default_substitutions()
 
 llvm_config.use_clang()
diff --git a/bolt/test/lit.site.cfg.py.in b/bolt/test/lit.site.cfg.py.in
index 7e63ffec7545..6286491a0d68 100644
--- a/bolt/test/lit.site.cfg.py.in
+++ b/bolt/test/lit.site.cfg.py.in
@@ -5,6 +5,7 @@ import sys
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.bolt_obj_root = "@BOLT_BINARY_DIR@"
+config.bolt_enable_runtime = @BOLT_ENABLE_RUNTIME@
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
 config.llvm_shlib_dir = "@SHLIBDIR@"
diff --git a/bolt/test/runtime/X86/fdata-escape-chars.ll b/bolt/test/runtime/X86/fdata-escape-chars.ll
index dfa053cd6e9e..757a8b609280 100644
--- a/bolt/test/runtime/X86/fdata-escape-chars.ll
+++ b/bolt/test/runtime/X86/fdata-escape-chars.ll
@@ -50,7 +50,7 @@ define internal void @static_symb_backslash_b() #0 {
   ret void
 }
 
-; REQUIRES: system-linux
+; REQUIRES: system-linux,bolt-runtime
 
 ; RUN: llc %s -o %t.s
 ; RUN: %clang %cflags -O0 %t.s -o %t.exe -Wl,-q
diff --git a/bolt/test/runtime/X86/instrumentation-dup-jts.s b/bolt/test/runtime/X86/instrumentation-dup-jts.s
index c548251d4046..a324b443976f 100755
--- a/bolt/test/runtime/X86/instrumentation-dup-jts.s
+++ b/bolt/test/runtime/X86/instrumentation-dup-jts.s
@@ -42,7 +42,7 @@
 #}
 
 
-# REQUIRES: system-linux
+# REQUIRES: system-linux,bolt-runtime
 
 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown \
 # RUN:   %s -o %t.o
diff --git a/bolt/test/runtime/X86/instrumentation-ind-calls.s b/bolt/test/runtime/X86/instrumentation-ind-calls.s
index 3c73597a0c0a..0f61441b0068 100755
--- a/bolt/test/runtime/X86/instrumentation-ind-calls.s
+++ b/bolt/test/runtime/X86/instrumentation-ind-calls.s
@@ -6,7 +6,7 @@
 # The solution is to temporarily fix RSP. Check that we correctly instrument
 # these cases.
 
-# REQUIRES: system-linux
+# REQUIRES: system-linux,bolt-runtime
 
 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown \
 # RUN:   %s -o %t.o
diff --git a/bolt/test/runtime/X86/instrumentation-pie.c b/bolt/test/runtime/X86/instrumentation-pie.c
index 75951af8c140..2f267252c7d8 100644
--- a/bolt/test/runtime/X86/instrumentation-pie.c
+++ b/bolt/test/runtime/X86/instrumentation-pie.c
@@ -19,7 +19,7 @@ int main(int argc, char **argv) {
 }
 
 /*
-REQUIRES: system-linux
+REQUIRES: system-linux,bolt-runtime
 
 RUN: %clang %cflags %s -o %t.exe -Wl,-q -pie -fpie
 
diff --git a/bolt/test/runtime/X86/instrumentation-shlib.c b/bolt/test/runtime/X86/instrumentation-shlib.c
index bf2b4c373e3d..f3124270574d 100644
--- a/bolt/test/runtime/X86/instrumentation-shlib.c
+++ b/bolt/test/runtime/X86/instrumentation-shlib.c
@@ -47,7 +47,7 @@ int main(int argc, char **argv) {
 #endif
 
 /*
-REQUIRES: system-linux
+REQUIRES: system-linux,bolt-runtime
 
 RUN: %clang %cflags %s -o %t.so -Wl,-q -fpie -fPIC -shared -DLIB
 RUN: %clang %cflags %s -o %t.exe -Wl,-q -ldl
diff --git a/bolt/test/runtime/X86/internal_call_instrument.test b/bolt/test/runtime/X86/internal_call_instrument.test
index 7f8bbf4bfc3a..8d359bad1441 100644
--- a/bolt/test/runtime/X86/internal_call_instrument.test
+++ b/bolt/test/runtime/X86/internal_call_instrument.test
@@ -1,6 +1,6 @@
 # Verify that instrumentation pass handles internal calls
 
-REQUIRES: x86_64-linux
+REQUIRES: x86_64-linux,bolt-runtime
 
 RUN: %clang -O3 %S/Inputs/internalcall-main.c %S/Inputs/internalcall.S -Wl,-q \
 RUN:   -o %t.exe
diff --git a/bolt/test/runtime/X86/user-func-reorder.c b/bolt/test/runtime/X86/user-func-reorder.c
index cf56cd89ab06..d0b2326bb982 100644
--- a/bolt/test/runtime/X86/user-func-reorder.c
+++ b/bolt/test/runtime/X86/user-func-reorder.c
@@ -25,7 +25,7 @@ int main(int argc, char **argv) {
 }
 
 /*
-REQUIRES: system-linux
+REQUIRES: system-linux,bolt-runtime
 
 RUN: %clang %cflags %s -o %t.exe -Wl,-q
 
diff --git a/bolt/tools/driver/CMakeLists.txt b/bolt/tools/driver/CMakeLists.txt
index 8ea0e5c2ee84..f6f0016ad0a6 100644
--- a/bolt/tools/driver/CMakeLists.txt
+++ b/bolt/tools/driver/CMakeLists.txt
@@ -8,11 +8,17 @@ set(LLVM_LINK_COMPONENTS
   Support
   )
 
+if (BOLT_ENABLE_RUNTIME)
+  set(BOLT_DRIVER_DEPS "bolt_rt")
+else()
+  set(BOLT_DRIVER_DEPS "")
+endif()
+
 add_llvm_tool(llvm-bolt
   llvm-bolt.cpp
 
   DEPENDS
-  bolt_rt
+  ${BOLT_DRIVER_DEPS}
   )
 
 add_llvm_tool_symlink(perf2bolt llvm-bolt)