feat: add dSYM outputs to C++-linked Zig targets

zig/private/common/zig_build.bzl

@@ -277,6 +277,16 @@ def zig_build_impl(ctx, *, kind):
     use_cc_common_link = settings.use_cc_common_link
     use_test_obj = kind == "zig_test" and use_cc_common_link and semver.gte(zigtoolchaininfo.zig_version, "0.16.0")
 
+    cc_toolchain = None
+    feature_configuration = None
+    generate_dsym_file = False
+    if use_cc_common_link and kind != "zig_static_library":
+        cc_toolchain, feature_configuration = find_cc_toolchain(ctx, mandatory = True)
+        generate_dsym_file = cc_common.is_enabled(
+            feature_configuration = feature_configuration,
+            feature_name = "generate_dsym_file",
+        )
+
     providers = []
     exported_library_to_link = None
     direct_data = []
@@ -317,8 +327,11 @@ def zig_build_impl(ctx, *, kind):
     elif ctx.attr.compiler_runtime == "exclude":
         args.add("-fno-compiler-rt")
 
-    if ctx.attr.strip_debug_symbols and not settings.strip:
-        args.add("-fstrip")
+    if ctx.attr.strip_debug_symbols:
+        if generate_dsym_file:
+            fail("'strip_debug_symbols' cannot be enabled when generating a dSYM")
+        if not settings.strip:
+            args.add("-fstrip")
 
     zig_lib_dir(
         zigtoolchaininfo = zigtoolchaininfo,
@@ -361,6 +374,15 @@ def zig_build_impl(ctx, *, kind):
             bin_output = ctx.actions.declare_file(bin_output_name)
         solib_parents = [""]
 
+    cc_link_kwargs = {}
+    if generate_dsym_file:
+        dsym_file = ctx.actions.declare_directory(ctx.label.name + ".dSYM", sibling = bin_output)
+        cc_link_kwargs = {
+            "additional_outputs": [dsym_file],
+            "variables_extension": {"dsym_path": dsym_file.path},
+        }
+        output_groups["dsyms"] = depset([dsym_file])
+
     if kind == "zig_test" and ctx.attr.test_runner:
         args.add("--test-runner", ctx.file.test_runner)
         direct_inputs.append(ctx.file.test_runner)
@@ -547,7 +569,6 @@ def zig_build_impl(ctx, *, kind):
                 **zig_build_kwargs
             )
 
-            cc_toolchain, feature_configuration = find_cc_toolchain(ctx, mandatory = True)
             library_to_link = cc_common.create_library_to_link(
                 actions = ctx.actions,
                 feature_configuration = feature_configuration,
@@ -571,6 +592,7 @@ def zig_build_impl(ctx, *, kind):
                 main_output = bin_output,
                 linking_contexts = [linking_context, root_module.cc_info.linking_context],
                 user_link_flags = linkopts,
+                **cc_link_kwargs
             )
         else:
             args.add(bin_output, format = "-femit-bin=%s")
@@ -638,7 +660,6 @@ def zig_build_impl(ctx, *, kind):
                 **zig_build_kwargs
             )
 
-            cc_toolchain, feature_configuration = find_cc_toolchain(ctx, mandatory = True)
             library_to_link = cc_common.create_library_to_link(
                 actions = ctx.actions,
                 feature_configuration = feature_configuration,
@@ -662,6 +683,7 @@ def zig_build_impl(ctx, *, kind):
                 main_output = bin_output,
                 linking_contexts = [linking_context, root_module.cc_info.linking_context],
                 user_link_flags = linkopts,
+                **cc_link_kwargs
             )
         else:
             args.add(bin_output, format = "-femit-bin=%s")
@@ -713,7 +735,6 @@ def zig_build_impl(ctx, *, kind):
                 **zig_build_kwargs
             )
 
-            cc_toolchain, feature_configuration = find_cc_toolchain(ctx, mandatory = True)
             library_to_link = cc_common.create_library_to_link(
                 actions = ctx.actions,
                 feature_configuration = feature_configuration,
@@ -738,6 +759,7 @@ def zig_build_impl(ctx, *, kind):
                 main_output = bin_output,
                 linking_contexts = [linking_context, root_module.cc_info.linking_context],
                 user_link_flags = linkopts,
+                **cc_link_kwargs
             )
 
             exported_library_to_link = link_outputs.library_to_link

zig/tests/BUILD.bazel

@@ -2,6 +2,7 @@ load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
 load(":bzlmod_zig_test.bzl", "bzlmod_zig_test_suite")
 load(":cache_test.bzl", "cache_test_suite")
 load(":config_test.bzl", "config_test_suite")
+load(":dsym_test.bzl", "dsym_test_suite")
 load(":emit_attr_test.bzl", "emit_attr_test_suite")
 load(":mode_test.bzl", "mode_test_suite")
 load(":module_info_test.bzl", "module_info_test_suite")
@@ -26,6 +27,8 @@ cache_test_suite(name = "cache_test")
 
 config_test_suite(name = "config_test")
 
+dsym_test_suite(name = "dsym_test")
+
 emit_attr_test_suite(name = "emit_attr_test")
 
 use_cc_common_link_test_suite(name = "use_cc_common_link_test")

zig/tests/dsym_test.bzl

@@ -0,0 +1,142 @@
+"""Analysis tests for dSYM outputs from cc_common.link."""
+
+load("@bazel_features//:features.bzl", "bazel_features")
+load("@bazel_skylib//lib:partial.bzl", "partial")
+load("@bazel_skylib//lib:sets.bzl", "sets")
+load("@bazel_skylib//lib:unittest.bzl", "analysistest", "asserts", "unittest")
+load(
+    ":util.bzl",
+    "assert_find_action",
+    "assert_flag_set",
+    "assert_flag_unset",
+    "canonical_label",
+)
+
+_APPLE_GENERATE_DSYM = "//command_line_option:apple_generate_dsym"
+_EXTRA_TOOLCHAINS = "//command_line_option:extra_toolchains"
+_STRIP = "//command_line_option:strip"
+_TARGET_PLATFORM = "//command_line_option:platforms"
+_SETTINGS_USE_CC_COMMON_LINK = canonical_label("@//zig/settings:use_cc_common_link")
+
+_PLATFORM_ZIG_ONLY_X86_64_LINUX = canonical_label("@//zig/tests/platforms:zig-only-x86_64-linux")
+_TOOLCHAIN_UNCONSTRAINED_DEFAULT_TEST = canonical_label("@//zig/tests/platforms:unconstrained_default_test_toolchain")
+_TOOLCHAIN_ZIG_ONLY_X86_64_LINUX = canonical_label("@//zig/tests/platforms:zig-only-x86_64-linux_toolchain")
+
+def _dsyms_enabled_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    target = analysistest.target_under_test(env)
+    output_groups = target[OutputGroupInfo]
+
+    asserts.true(env, hasattr(output_groups, "dsyms"), "dSYMs should be exposed when the C++ toolchain enables generate_dsym_file.")
+    dsyms = output_groups.dsyms.to_list() if hasattr(output_groups, "dsyms") else []
+    asserts.equals(env, 1, len(dsyms), "Exactly one dSYM should be exposed.")
+    if dsyms:
+        dsym = dsyms[0]
+        asserts.true(env, dsym.is_directory, "The dSYM should be a directory artifact.")
+        asserts.equals(env, target.label.name + ".dSYM", dsym.basename)
+
+        link = assert_find_action(env, "CppLink")
+        asserts.true(env, sets.contains(sets.make(link.outputs.to_list()), dsym), "The CppLink action should produce the dSYM.")
+
+        link_variables = link.argv + getattr(link, "env", {}).values()
+        asserts.true(
+            env,
+            any([dsym.path in value for value in link_variables]),
+            "The CppLink command line or environment should contain the dSYM path.",
+        )
+
+    for action in analysistest.target_actions(env):
+        if action.mnemonic in ["ZigBuildLib", "ZigBuildTest"]:
+            assert_flag_unset(env, "-fstrip", action.argv)
+
+    return analysistest.end(env)
+
+_dsyms_enabled_test = analysistest.make(
+    _dsyms_enabled_test_impl,
+    config_settings = {
+        _APPLE_GENERATE_DSYM: True,
+        _SETTINGS_USE_CC_COMMON_LINK: True,
+        _STRIP: "never",
+    },
+)
+
+def _dsyms_strip_debug_symbols_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    asserts.expect_failure(env, "'strip_debug_symbols' cannot be enabled when generating a dSYM")
+    return analysistest.end(env)
+
+_dsyms_strip_debug_symbols_test = analysistest.make(
+    _dsyms_strip_debug_symbols_test_impl,
+    config_settings = {
+        _APPLE_GENERATE_DSYM: True,
+        _SETTINGS_USE_CC_COMMON_LINK: True,
+    },
+    expect_failure = True,
+)
+
+def _dsyms_disabled_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    target = analysistest.target_under_test(env)
+    output_groups = target[OutputGroupInfo]
+
+    asserts.false(env, hasattr(output_groups, "dsyms"), "dSYMs should not be exposed when generate_dsym_file is disabled.")
+    assert_find_action(env, "CppLink")
+    assert_flag_set(env, "-fstrip", assert_find_action(env, "ZigBuildLib").argv)
+
+    return analysistest.end(env)
+
+_dsyms_disabled_test = analysistest.make(
+    _dsyms_disabled_test_impl,
+    config_settings = {
+        _APPLE_GENERATE_DSYM: False,
+        _SETTINGS_USE_CC_COMMON_LINK: True,
+        _STRIP: "always",
+    },
+)
+
+def _dsyms_without_cc_toolchain_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    target = analysistest.target_under_test(env)
+    output_groups = target[OutputGroupInfo]
+
+    asserts.false(env, hasattr(output_groups, "dsyms"), "A Zig-only target should not expose a dSYM that no action can create.")
+    assert_find_action(env, "ZigBuildExe")
+    asserts.false(
+        env,
+        any([action.mnemonic == "CppLink" for action in analysistest.target_actions(env)]),
+        "A Zig-only target should not create a CppLink action.",
+    )
+
+    return analysistest.end(env)
+
+def _zig_only_config(generate_dsym):
+    return {
+        _APPLE_GENERATE_DSYM: generate_dsym,
+        _EXTRA_TOOLCHAINS: ",".join([
+            _TOOLCHAIN_ZIG_ONLY_X86_64_LINUX,
+        ] + ([_TOOLCHAIN_UNCONSTRAINED_DEFAULT_TEST] if bazel_features.toolchains.has_default_test_toolchain_type else [])),
+        _SETTINGS_USE_CC_COMMON_LINK: False,
+        _TARGET_PLATFORM: _PLATFORM_ZIG_ONLY_X86_64_LINUX,
+    }
+
+_dsyms_without_cc_toolchain_requested_test = analysistest.make(
+    _dsyms_without_cc_toolchain_test_impl,
+    config_settings = _zig_only_config(True),
+)
+
+_dsyms_without_cc_toolchain_unrequested_test = analysistest.make(
+    _dsyms_without_cc_toolchain_test_impl,
+    config_settings = _zig_only_config(False),
+)
+
+def dsym_test_suite(name):
+    unittest.suite(
+        name,
+        partial.make(_dsyms_enabled_test, name = "dsym_binary_enabled_test", target_under_test = "//zig/tests/simple-binary:binary", size = "small", target_compatible_with = ["@platforms//os:macos"]),
+        partial.make(_dsyms_enabled_test, name = "dsym_shared_library_enabled_test", target_under_test = "//zig/tests/simple-shared-library:shared", size = "small", target_compatible_with = ["@platforms//os:macos"]),
+        partial.make(_dsyms_enabled_test, name = "dsym_test_enabled_test", target_under_test = "//zig/tests/simple-test:test", size = "small", target_compatible_with = ["@platforms//os:macos"]),
+        partial.make(_dsyms_strip_debug_symbols_test, name = "dsym_strip_debug_symbols_test", target_under_test = "//zig/tests/strip_debug_symbols:binary-strip", size = "small", target_compatible_with = ["@platforms//os:macos"]),
+        partial.make(_dsyms_disabled_test, name = "dsym_binary_disabled_test", target_under_test = "//zig/tests/simple-binary:binary", size = "small"),
+        partial.make(_dsyms_without_cc_toolchain_requested_test, name = "dsym_zig_only_requested_test", target_under_test = "//zig/tests/simple-binary:binary", size = "small"),
+        partial.make(_dsyms_without_cc_toolchain_unrequested_test, name = "dsym_zig_only_unrequested_test", target_under_test = "//zig/tests/simple-binary:binary", size = "small"),
+    )