[compiler-rt] Allow running tests without installing first

Currently, the testsuite uses the default runtimes path to find the
runtimes libraries which may or may not match the just-built runtimes.
This change uses the -resource-dir flag for clang whenever
COMPILER_RT_TEST_STANDALONE_BUILD_LIBS is set to ensure that we are
actually testing the currently built libraries rather than the ones
bundled with ${COMPILER_RT_TEST_COMPILER}.

The existing logic works fine when clang and compiler-rt share the same
build directory -DLLVM_ENABLE_PROJECTS=clang;compiler-rt, but when building
compiler-rt separately we need to tell the compiler used for the tests
where it can find the just-built libraries.


This mostly fixes check-all in my configuration:
```
cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -G Ninja
-DCMAKE_C_COMPILER=$HOME/output/upstream-llvm/bin/clang
-DCMAKE_CXX_COMPILER=$HOME/output/upstream-llvm/bin/clang++
-DCOMPILER_RT_INCLUDE_TESTS=ON
-DLLVM_EXTERNAL_LIT=$HOME/build/upstream-llvm-project-build/bin/llvm-lit
-DLLVM_CMAKE_DIR=$HOME/output/upstream-llvm
-DCOMPILER_RT_DEBUG=OFF
-S $HOME/src/upstream-llvm-project/compiler-rt
-B $HOME/src/upstream-llvm-project/compiler-rt/cmake-build-all-sanitizers
```

I am still seeing two test failures due to an msan error inside
__gxx_personality_v0, but that is most likely due to an uninstrumented
`/lib/x86_64-linux-gnu/libgcc_s.so.1` being used by these tests.

Pull Request: llvm#83088

Author: arichardson

compiler-rt/CMakeLists.txt

@@ -571,6 +571,27 @@ string(APPEND COMPILER_RT_TEST_COMPILER_CFLAGS " ${stdlib_flag}")
 string(REPLACE " " ";" COMPILER_RT_UNITTEST_CFLAGS "${COMPILER_RT_TEST_COMPILER_CFLAGS}")
 set(COMPILER_RT_UNITTEST_LINK_FLAGS ${COMPILER_RT_UNITTEST_CFLAGS})
 
+option(COMPILER_RT_TEST_STANDALONE_BUILD_LIBS
+  "When set to ON and testing in a standalone build, test the runtime \
+  libraries built by this standalone build rather than the runtime libraries \
+  shipped with the compiler (used for testing). When set to OFF and testing \
+  in a standalone build, test the runtime libraries shipped with the compiler \
+  (used for testing). This option has no effect if the compiler and this \
+  build are configured to use the same runtime library path."
+  ON)
+if (COMPILER_RT_TEST_STANDALONE_BUILD_LIBS)
+  # Ensure that the unit tests can find the sanitizer headers prior to installation.
+  list(APPEND COMPILER_RT_UNITTEST_CFLAGS "-I${CMAKE_CURRENT_LIST_DIR}/include")
+  # Ensure that unit tests link against the just-built runtime libraries instead
+  # of the ones bundled with the compiler by overriding the resource directory.
+  #
+  if ("${COMPILER_RT_TEST_COMPILER_ID}" MATCHES "Clang")
+    list(APPEND COMPILER_RT_UNITTEST_LINK_FLAGS "-resource-dir=${CMAKE_CURRENT_BINARY_DIR}")
+  endif()
+  get_compiler_rt_output_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} output_dir)
+  list(APPEND COMPILER_RT_UNITTEST_LINK_FLAGS "-Wl,-rpath,${output_dir}")
+endif()
+
 if(COMPILER_RT_USE_LLVM_UNWINDER)
   # We're linking directly against the libunwind that we're building so don't
   # try to link in the toolchain's default libunwind which may be missing.

compiler-rt/cmake/Modules/AddCompilerRT.cmake

@@ -768,6 +768,7 @@ function(configure_compiler_rt_lit_site_cfg input output)
   get_compiler_rt_output_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} output_dir)
 
   string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} COMPILER_RT_RESOLVED_TEST_COMPILER ${COMPILER_RT_TEST_COMPILER})
+  string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} COMPILER_RT_RESOLVED_OUTPUT_DIR ${COMPILER_RT_OUTPUT_DIR})
   string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} COMPILER_RT_RESOLVED_LIBRARY_OUTPUT_DIR ${output_dir})
 
   configure_lit_site_cfg(${input} ${output})

compiler-rt/test/CMakeLists.txt

@@ -1,14 +1,6 @@
 # Needed for lit support in standalone builds.
 include(AddLLVM)
 
-option(COMPILER_RT_TEST_STANDALONE_BUILD_LIBS
-  "When set to ON and testing in a standalone build, test the runtime \
-  libraries built by this standalone build rather than the runtime libraries \
-  shipped with the compiler (used for testing). When set to OFF and testing \
-  in a standalone build, test the runtime libraries shipped with the compiler \
-  (used for testing). This option has no effect if the compiler and this \
-  build are configured to use the same runtime library path."
-  ON)
 pythonize_bool(COMPILER_RT_TEST_STANDALONE_BUILD_LIBS)
 
 pythonize_bool(LLVM_ENABLE_EXPENSIVE_CHECKS)

compiler-rt/test/fuzzer/lit.cfg.py

@@ -101,6 +101,7 @@ def generate_compiler_cmd(is_cpp=True, fuzzer_enabled=True, msan_enabled=False):
     return " ".join(
         [
             compiler_cmd,
+            config.target_cflags,
             std_cmd,
             "-O2 -gline-tables-only",
             sanitizers_cmd,

compiler-rt/test/lit.common.cfg.py

@@ -14,6 +14,27 @@
 import lit.util
 
 
+def get_path_from_clang(args, allow_failure):
+    clang_cmd = [
+        config.clang.strip(),
+        f"--target={config.target_triple}",
+        *args,
+    ]
+    path = None
+    try:
+        result = subprocess.run(
+            clang_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=True
+        )
+        path = result.stdout.decode().strip()
+    except subprocess.CalledProcessError as e:
+        msg = f"Failed to run {clang_cmd}\nrc:{e.returncode}\nstdout:{e.stdout}\ne.stderr{e.stderr}"
+        if allow_failure:
+            lit_config.warning(msg)
+        else:
+            lit_config.fatal(msg)
+    return path, clang_cmd
+
+
 def find_compiler_libdir():
     """
     Returns the path to library resource directory used
@@ -26,26 +47,6 @@ def find_compiler_libdir():
         # TODO: Support other compilers.
         return None
 
-    def get_path_from_clang(args, allow_failure):
-        clang_cmd = [
-            config.clang.strip(),
-            f"--target={config.target_triple}",
-        ]
-        clang_cmd.extend(args)
-        path = None
-        try:
-            result = subprocess.run(
-                clang_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=True
-            )
-            path = result.stdout.decode().strip()
-        except subprocess.CalledProcessError as e:
-            msg = f"Failed to run {clang_cmd}\nrc:{e.returncode}\nstdout:{e.stdout}\ne.stderr{e.stderr}"
-            if allow_failure:
-                lit_config.warning(msg)
-            else:
-                lit_config.fatal(msg)
-        return path, clang_cmd
-
     # Try using `-print-runtime-dir`. This is only supported by very new versions of Clang.
     # so allow failure here.
     runtime_dir, clang_cmd = get_path_from_clang(
@@ -168,10 +169,45 @@ def push_dynamic_library_lookup_path(config, new_path):
             r"/i386(?=-[^/]+$)", "/x86_64", config.compiler_rt_libdir
         )
 
+
+# Check if the test compiler resource dir matches the local build directory
+# (which happens with -DLLVM_ENABLE_PROJECTS=clang;compiler-rt) or if we are
+# using an installed clang to test compiler-rt standalone. In the latter case
+# we may need to override the resource dir to match the path of the just-built
+# compiler-rt libraries.
+test_cc_resource_dir, _ = get_path_from_clang(
+    shlex.split(config.target_cflags) + ["-print-resource-dir"], allow_failure=True
+)
+# Normalize the path for comparison
+if test_cc_resource_dir is not None:
+    test_cc_resource_dir = os.path.realpath(test_cc_resource_dir)
+if lit_config.debug:
+    lit_config.note(f"Resource dir for {config.clang} is {test_cc_resource_dir}")
+local_build_resource_dir = os.path.realpath(config.compiler_rt_output_dir)
+if test_cc_resource_dir != local_build_resource_dir:
+    if config.test_standalone_build_libs and config.compiler_id == "Clang":
+        if lit_config.debug:
+            lit_config.note(
+                f"Overriding test compiler resource dir to use "
+                f'libraries in "{config.compiler_rt_libdir}"'
+            )
+        # Ensure that we use the just-built static libraries when linking by
+        # overriding the Clang resource directory. Additionally, we want to use
+        # the builtin headers shipped with clang (e.g. stdint.h), so we
+        # explicitly add this as an include path (since the headers are not
+        # going to be in the current compiler-rt build directory).
+        # We also tell the linker to add an RPATH entry for the local library
+        # directory so that the just-built shared libraries are used.
+        config.target_cflags += f" -nobuiltininc"
+        config.target_cflags += f" -I{config.compiler_rt_src_root}/include"
+        config.target_cflags += f" -idirafter {test_cc_resource_dir}/include"
+        config.target_cflags += f" -resource-dir={config.compiler_rt_output_dir}"
+        config.target_cflags += f" -Wl,-rpath,{config.compiler_rt_libdir}"
+
 # Ask the compiler for the path to libraries it is going to use. If this
 # doesn't match config.compiler_rt_libdir then it means we might be testing the
 # compiler's own runtime libraries rather than the ones we just built.
-# Warn about about this and handle appropriately.
+# Warn about this and handle appropriately.
 compiler_libdir = find_compiler_libdir()
 if compiler_libdir:
     compiler_rt_libdir_real = os.path.realpath(config.compiler_rt_libdir)
@@ -182,7 +218,7 @@ def push_dynamic_library_lookup_path(config, new_path):
             f'compiler-rt libdir:  "{compiler_rt_libdir_real}"'
         )
         if config.test_standalone_build_libs:
-            # Use just built runtime libraries, i.e. the the libraries this built just built.
+            # Use just built runtime libraries, i.e. the libraries this build just built.
             if not config.test_suite_supports_overriding_runtime_lib_path:
                 # Test suite doesn't support this configuration.
                 # TODO(dliew): This should be an error but it seems several bots are

compiler-rt/test/lit.common.configured.in

@@ -27,6 +27,7 @@ set_default("compiler_id", "@COMPILER_RT_TEST_COMPILER_ID@")
 set_default("python_executable", "@Python3_EXECUTABLE@")
 set_default("compiler_rt_debug", @COMPILER_RT_DEBUG_PYBOOL@)
 set_default("compiler_rt_intercept_libdispatch", @COMPILER_RT_INTERCEPT_LIBDISPATCH_PYBOOL@)
+set_default("compiler_rt_output_dir", "@COMPILER_RT_RESOLVED_OUTPUT_DIR@")
 set_default("compiler_rt_libdir", "@COMPILER_RT_RESOLVED_LIBRARY_OUTPUT_DIR@")
 set_default("emulator", "@COMPILER_RT_EMULATOR@")
 set_default("asan_shadow_scale", "@COMPILER_RT_ASAN_SHADOW_SCALE@")

compiler-rt/test/safestack/lit.cfg.py

@@ -13,10 +13,16 @@
 
 # Add clang substitutions.
 config.substitutions.append(
-    ("%clang_nosafestack ", config.clang + " -O0 -fno-sanitize=safe-stack ")
+    (
+        "%clang_nosafestack ",
+        config.clang + config.target_cflags + " -O0 -fno-sanitize=safe-stack ",
+    )
 )
 config.substitutions.append(
-    ("%clang_safestack ", config.clang + " -O0 -fsanitize=safe-stack ")
+    (
+        "%clang_safestack ",
+        config.clang + config.target_cflags + " -O0 -fsanitize=safe-stack ",
+    )
 )
 
 if config.lto_supported: