Make it possible to use llvm-cov with bazel coverage

crosstool/BUILD.tpl

@@ -122,13 +122,23 @@ filegroup(
     ],
 )
 
+filegroup(
+    name = "tools_coverage",
+    srcs = [
+        ":gcov.sh",
+        ":llvm-profdata.sh",
+        ":llvm-cov.sh",
+    ],
+)
+
 [
     cc_toolchain(
         name = "cc-compiler-" + arch,
         all_files = ":tools",
         ar_files = ":tools",
         as_files = ":tools",
         compiler_files = ":tools",
+        coverage_files = ":tools_coverage",
         dwp_files = ":empty",
         linker_files = ":tools",
         objcopy_files = ":empty",

crosstool/cov_tool_wrapper.sh.tpl

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+%{command} "$@"

crosstool/osx_cc_configure.bzl

@@ -88,6 +88,26 @@ def _generate_system_modulemap(repository_ctx, script, output):
 def _copy_file(repository_ctx, src, dest):
     repository_ctx.file(dest, content = repository_ctx.read(src))
 
+def _get_tool_wrapper(repository_ctx, wrapper_script_name, tool_name, path_env_var):
+    cov_tool_wrapper_template = Label("@build_bazel_apple_support//crosstool:cov_tool_wrapper.sh.tpl")
+
+    command = "xcrun --run " + tool_name
+
+    override_path = repository_ctx.os.environ.get(path_env_var)
+    if override_path:
+        if not override_path.startswith("/"):
+            override_path = repository_ctx.which(override_path)
+        command = '"{}"'.format(override_path)
+
+    repository_ctx.template(
+        wrapper_script_name,
+        cov_tool_wrapper_template,
+        {
+            "%{command}": command,
+        },
+    )
+    return wrapper_script_name
+
 def configure_osx_toolchain(repository_ctx):
     """Configure C++ toolchain on macOS.
 
@@ -153,11 +173,9 @@ def configure_osx_toolchain(repository_ctx):
         )
 
     tool_paths = {}
-    gcov_path = repository_ctx.os.environ.get("GCOV")
-    if gcov_path != None:
-        if not gcov_path.startswith("/"):
-            gcov_path = repository_ctx.which(gcov_path)
-        tool_paths["gcov"] = gcov_path
+    tool_paths["gcov"] = _get_tool_wrapper(repository_ctx, "gcov.sh", "llvm-profdata", "GCOV")
+    tool_paths["llvm-cov"] = _get_tool_wrapper(repository_ctx, "llvm-cov.sh", "llvm-cov", "BAZEL_LLVM_COV")
+    tool_paths["llvm-profdata"] = _get_tool_wrapper(repository_ctx, "llvm-profdata.sh", "llvm-profdata", "BAZEL_LLVM_PROFDATA")
 
     features = []
     if _succeeds(repository_ctx, "ld", "-no_warn_duplicate_libraries", "-v"):

crosstool/setup.bzl

@@ -56,6 +56,8 @@ _apple_cc_autoconf = repository_rule(
         _OLD_DISABLE_ENV_VAR,
         "APPLE_SUPPORT_LAYERING_CHECK_BETA",
         "BAZEL_ALLOW_NON_APPLICATIONS_XCODE",  # Signals to configure_osx_toolchain that some Xcodes may live outside of /Applications and we need to probe further when detecting/configuring them.
+        "BAZEL_LLVM_COV",  # Makes it possible to override the llvm-cov path.
+        "BAZEL_LLVM_PROFDATA",  # Makes it possible to override the llvm-profdata path.
         "DEVELOPER_DIR",  # Used for making sure we use the right Xcode for compiling toolchain binaries
         "GCOV",  # TODO: Remove this
         "USE_CLANG_CL",  # Kept as a hack for those who rely on this invaliding the toolchain