Add an option to disable QEMU testing

CMakeLists.txt

@@ -150,9 +150,14 @@ option(
     "During checkout, apply optional downstream patches to
     llvm-project to improve performance."
 )
+option(
+    ENABLE_QEMU_TESTING
+    "Enable tests that use QEMU. This option is ON by default."
+    ON
+)
 option(
     ENABLE_FVP_TESTING
-    "Tests using FVP need to be explictly enabled."
+    "Enable tests that use FVPs. This option is OFF by default."
 )
 set(
     FVP_INSTALL_DIR
@@ -596,6 +601,7 @@ if(NOT PREBUILT_TARGET_LIBRARIES)
         -DENABLE_VARIANTS=${ENABLE_VARIANTS_PASSTHROUGH}
         -DLIBC_HDRGEN=${LIBC_HDRGEN}
         -DFVP_INSTALL_DIR=${FVP_INSTALL_DIR}
+        -DENABLE_QEMU_TESTING=${ENABLE_QEMU_TESTING}
         -DENABLE_FVP_TESTING=${ENABLE_FVP_TESTING}
         -DFVP_CONFIG_DIR=${CMAKE_CURRENT_SOURCE_DIR}/fvp/config
         -DFETCHCONTENT_SOURCE_DIR_LLVMPROJECT=${FETCHCONTENT_SOURCE_DIR_LLVMPROJECT}

arm-multilib/CMakeLists.txt

@@ -33,9 +33,14 @@ set(C_LIBRARY "picolibc" CACHE STRING "Which C library to use.")
 set_property(CACHE C_LIBRARY PROPERTY STRINGS picolibc newlib llvmlibc)
 set(LLVM_BINARY_DIR "" CACHE PATH "Path to LLVM toolchain build or install root.")
 set(LIBC_HDRGEN "" CACHE PATH "Path to prebuilt lbc-hdrgen if not included in LLVM binaries set by LLVM_BINARY_DIR")
+option(
+    ENABLE_QEMU_TESTING
+    "Enable tests that use QEMU. This option is ON by default."
+    ON
+)
 option(
     ENABLE_FVP_TESTING
-    "Tests using FVP need to be explictly enabled."
+    "Enable tests that use FVPs. This option is OFF by default."
 )
 set(
     FVP_INSTALL_DIR
@@ -162,9 +167,9 @@ foreach(lib_idx RANGE ${lib_count_dec})
             file(READ ${variant_json_file} variant_json_str)
             string(JSON test_executor GET ${variant_json_str} "args" "common" "TEST_EXECUTOR")
 
-            # FVP testing should default to off, so override any 
-            # settings from the JSON.
-            if(test_executor STREQUAL "fvp" AND NOT ${ENABLE_FVP_TESTING})
+            # The multilib project can be configured to disable QEMU and/or FVP
+            # testing, which will need to override the settings from the json.
+            if((test_executor STREQUAL "qemu" AND NOT ${ENABLE_QEMU_TESTING}) OR (test_executor STREQUAL "fvp" AND NOT ${ENABLE_FVP_TESTING}))
                 list(APPEND additional_cmake_args "-DENABLE_LIBC_TESTS=OFF" "-DENABLE_COMPILER_RT_TESTS=OFF" "-DENABLE_LIBCXX_TESTS=OFF")
                 set(read_ENABLE_LIBC_TESTS "OFF")
                 set(read_ENABLE_COMPILER_RT_TESTS "OFF")

docs/building-from-source.md

@@ -36,6 +36,10 @@ $ brew install llvm python3 git make ninja qemu cmake
 $ pip install meson
 ```
 
+Testing with QEMU is enabled by default, but can be disabled using the 
+`-DENABLE_QEMU_TESTING=OFF` CMake option if testing is not required or QEMU is
+not installed.
+
 Some recent targets are not supported by QEMU, for these the Arm FVP models are
 used instead. These models are available free-of-change but are not
 open-source, and come with their own licenses.