From e856912402134d8ef00c8dd3fa3f94bc237a1fa1 Mon Sep 17 00:00:00 2001
From: UebelAndre <github@uebelandre.com>
Date: Fri, 15 May 2026 08:46:11 -0700
Subject: [PATCH] Fix coverage with MacOS autoconf toolchains

---
 .bazelci/presubmit.yml                          | 17 ++++++++++++++++-
 cc/private/coverage/collect_cc_coverage.sh      | 10 ++++++++++
 cc/private/toolchain/unix_cc_configure.bzl      |  7 +++++++
 .../toolchain/unix_cc_toolchain_config.bzl      | 12 ++++++++++++
 4 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/.bazelci/presubmit.yml b/.bazelci/presubmit.yml
index e2217daa9..dab5f8b70 100644
--- a/.bazelci/presubmit.yml
+++ b/.bazelci/presubmit.yml
@@ -37,6 +37,11 @@ test_targets_bazel_6: &test_targets_bazel_6
   - "-//tests/strip_include_prefix:test_include_textual"  # Not supported in bazel <9.
 
 common_coverage_flags: &common_coverage_flags
+  # Test failures are not collected under `coverage` invocations.
+  # https://github.com/bazelbuild/continuous-integration/issues/1838
+  - "--test_output=errors"
+
+windows_coverage_flags: &windows_coverage_flags
   # Starting in Bazel 9 coverage collection causes some tests to fail.
   # https://github.com/bazelbuild/rules_cc/issues/613
   - "--test_env=IGNORE_COVERAGE_COLLECTION_FAILURES=1"
@@ -45,6 +50,11 @@ common_coverage_flags: &common_coverage_flags
   - "--test_output=errors"
 
 coverage_flags_bazel_less_than_9: &coverage_flags_bazel_less_than_9
+  # See above
+  - "--test_output=errors"
+  - "--deleted_packages=//tests/local_includes"
+
+windows_coverage_flags_bazel_less_than_9: &windows_coverage_flags_bazel_less_than_9
   # See above
   - "--test_env=IGNORE_COVERAGE_COLLECTION_FAILURES=1"
   - "--test_output=errors"
@@ -127,6 +137,8 @@ tasks:
     platform: windows
     build_targets: *build_targets
     test_targets: *test_targets
+    coverage_flags: *windows_coverage_flags
+    coverage_targets: *test_targets
 
 # Bazel 7
   ubuntu2004_bazel_7:
@@ -207,6 +219,8 @@ tasks:
     test_targets: *test_targets_bazel_6
     build_flags: *flags_bazel_less_than_9
     test_flags: *flags_bazel_less_than_9
+    coverage_flags: *windows_coverage_flags_bazel_less_than_9
+    coverage_targets: *test_targets_bazel_6
 
 # Bazel 9
   ubuntu2004:
@@ -238,6 +252,8 @@ tasks:
     bazel: 9.x
     build_targets: *build_targets
     test_targets: *test_targets
+    coverage_flags: *windows_coverage_flags
+    coverage_targets: *test_targets
   ubuntu_bzlmod:
     name: Ubuntu 20.04 (Bazel 9, bzlmod)
     bazel: 9.x
@@ -250,7 +266,6 @@ tasks:
   ubuntu_rule_based_toolchains_bazel_7:
     name: Ubuntu rule-based toolchains (Bazel 7)
     bazel: 7.2.1
-    name: Ubuntu rule-based toolchains
     platform: ubuntu1804
     working_directory: examples/rule_based_toolchain
     build_flags:
diff --git a/cc/private/coverage/collect_cc_coverage.sh b/cc/private/coverage/collect_cc_coverage.sh
index 5d3dc6227..609284b78 100755
--- a/cc/private/coverage/collect_cc_coverage.sh
+++ b/cc/private/coverage/collect_cc_coverage.sh
@@ -191,7 +191,17 @@ function main() {
   # format by LcovMerger.
   # TODO(#5881): Convert profdata reports to lcov.
   if uses_llvm; then
+    if [[ -z "${LLVM_PROFDATA:-}" ]]; then
+        echo "LLVM_PROFDATA is not set. The toolchain must provide llvm-profdata" \
+             "in tool_paths to support coverage with clang." >&2
+        exit 1
+    fi
     if [[ "${GENERATE_LLVM_LCOV}" == "1" ]]; then
+        if [[ -z "${LLVM_COV:-}" ]]; then
+            echo "LLVM_COV is not set. The toolchain must provide llvm-cov" \
+                 "in tool_paths to support lcov coverage with clang." >&2
+            exit 1
+        fi
         BAZEL_CC_COVERAGE_TOOL="LLVM_LCOV"
     else
         BAZEL_CC_COVERAGE_TOOL="PROFDATA"
diff --git a/cc/private/toolchain/unix_cc_configure.bzl b/cc/private/toolchain/unix_cc_configure.bzl
index fbb4f1981..b85a2e8a6 100644
--- a/cc/private/toolchain/unix_cc_configure.bzl
+++ b/cc/private/toolchain/unix_cc_configure.bzl
@@ -395,6 +395,13 @@ def configure_unix_toolchain(repository_ctx, cpu_value, overridden_tools):
     if darwin:
         overridden_tools["gcc"] = "cc_wrapper.sh"
         overridden_tools["ar"] = _find_generic(repository_ctx, "libtool", "LIBTOOL", overridden_tools)
+        xcrun = repository_ctx.which("xcrun")
+        if xcrun:
+            for tool_name in ["llvm-cov", "llvm-profdata"]:
+                if overridden_tools.get(tool_name) == None:
+                    xcrun_result = repository_ctx.execute([xcrun, "--find", tool_name])
+                    if xcrun_result.return_code == 0:
+                        overridden_tools[tool_name] = xcrun_result.stdout.strip()
 
     auto_configure_warning_maybe(repository_ctx, "CC used: " + str(cc))
     tool_paths = _get_tool_paths(repository_ctx, overridden_tools)
diff --git a/cc/private/toolchain/unix_cc_toolchain_config.bzl b/cc/private/toolchain/unix_cc_toolchain_config.bzl
index 4fa2d2d0b..9996ccee9 100644
--- a/cc/private/toolchain/unix_cc_toolchain_config.bzl
+++ b/cc/private/toolchain/unix_cc_toolchain_config.bzl
@@ -258,6 +258,18 @@ def _impl(ctx):
         )
         action_configs.append(llvm_cov_action)
 
+    llvm_profdata = ctx.attr.tool_paths.get("llvm-profdata")
+    if llvm_profdata:
+        llvm_profdata_action = action_config(
+            action_name = ACTION_NAMES.llvm_profdata,
+            tools = [
+                tool(
+                    path = llvm_profdata,
+                ),
+            ],
+        )
+        action_configs.append(llvm_profdata_action)
+
     objcopy = ctx.attr.tool_paths.get("objcopy")
     if objcopy:
         objcopy_action = action_config(