Bazel: fix non-swift macOS builds

This is meant to be cleaned up in a later PR with respect to the TODOs.

.bazelrc

@@ -10,11 +10,6 @@ common --override_module=semmle_code=%workspace%/misc/bazel/semmle_code_stub
 
 build --repo_env=CC=clang --repo_env=CXX=clang++
 
-build:linux --cxxopt=-std=c++20 --host_cxxopt=-std=c++20
-# we currently cannot built the swift extractor for ARM
-build:macos --cxxopt=-std=c++20 --host_cxxopt=-std=c++20 --copt=-arch --copt=x86_64 --linkopt=-arch --linkopt=x86_64
-build:windows --cxxopt=/std:c++20 --cxxopt=/Zc:preprocessor --host_cxxopt=/std:c++20 --host_cxxopt=/Zc:preprocessor
-
 # this requires developer mode, but is required to have pack installer functioning
 startup --windows_enable_symlinks
 common --enable_runfiles

.github/workflows/go-tests-other-os.yml

@@ -7,6 +7,9 @@ on:
       - .github/workflows/go-tests-other-os.yml
       - .github/actions/**
       - codeql-workspace.yml
+      - MODULE.bazel
+      - .bazelrc
+      - misc/bazel/**
 
 permissions:
   contents: read

.github/workflows/go-tests.yml

@@ -15,6 +15,9 @@ on:
       - .github/workflows/go-tests.yml
       - .github/actions/**
       - codeql-workspace.yml
+      - MODULE.bazel
+      - .bazelrc
+      - misc/bazel/**
 
 permissions:
   contents: read

misc/bazel/os.bzl

@@ -0,0 +1,38 @@
+""" Os detection facilities. """
+
+def os_select(
+        ctx = None,
+        *,
+        linux = None,
+        windows = None,
+        macos = None,
+        default = None):
+    """
+    This can work both in a macro and a rule context to choose something based on the current OS.
+    If used in a rule implementation, you need to pass `ctx` and add `OS_DETECTION_ATTRS` to the
+    rule attributes.
+    """
+    choices = {
+        "linux": linux or default,
+        "windows": windows or default,
+        "macos": macos or default,
+    }
+    if not ctx:
+        return select({
+            "@platforms//os:%s" % os: v
+            for os, v in choices.items()
+            if v != None
+        })
+
+    for os, v in choices.items():
+        if ctx.target_platform_has_constraint(getattr(ctx.attr, "_%s_constraint" % os)[platform_common.ConstraintValueInfo]):
+            if v == None:
+                fail("%s not supported by %s" % (os, ctx.label))
+            return v
+    fail("Unknown OS detected")
+
+OS_DETECTION_ATTRS = {
+    "_windows_constraint": attr.label(default = "@platforms//os:windows"),
+    "_macos_constraint": attr.label(default = "@platforms//os:macos"),
+    "_linux_constraint": attr.label(default = "@platforms//os:linux"),
+}

misc/bazel/pkg.bzl

@@ -7,6 +7,7 @@ load("@rules_pkg//pkg:mappings.bzl", "pkg_attributes", "pkg_filegroup", "pkg_fil
 load("@rules_pkg//pkg:pkg.bzl", "pkg_zip")
 load("@rules_pkg//pkg:providers.bzl", "PackageFilegroupInfo", "PackageFilesInfo")
 load("@rules_python//python:defs.bzl", "py_binary")
+load("//misc/bazel:os.bzl", "OS_DETECTION_ATTRS", "os_select")
 
 def _make_internal(name):
     def internal(suffix = "internal", *args):
@@ -15,11 +16,6 @@ def _make_internal(name):
 
     return internal
 
-_PLAT_DETECTION_ATTRS = {
-    "_windows": attr.label(default = "@platforms//os:windows"),
-    "_macos": attr.label(default = "@platforms//os:macos"),
-}
-
 _PLAT_PLACEHOLDER = "{CODEQL_PLATFORM}"
 
 def _expand_path(path, platform):
@@ -28,28 +24,8 @@ def _expand_path(path, platform):
         return ("arch", path)
     return ("generic", path)
 
-def _platform_select(
-        ctx = None,
-        *,
-        linux,
-        windows,
-        macos):
-    if ctx:
-        if ctx.target_platform_has_constraint(ctx.attr._windows[platform_common.ConstraintValueInfo]):
-            return windows
-        elif ctx.target_platform_has_constraint(ctx.attr._macos[platform_common.ConstraintValueInfo]):
-            return macos
-        else:
-            return linux
-    else:
-        return select({
-            "@platforms//os:linux": linux,
-            "@platforms//os:macos": macos,
-            "@platforms//os:windows": windows,
-        })
-
 def _detect_platform(ctx = None):
-    return _platform_select(ctx, linux = "linux64", macos = "osx64", windows = "win64")
+    return os_select(ctx, linux = "linux64", macos = "osx64", windows = "win64")
 
 def codeql_pkg_files(
         *,
@@ -131,7 +107,7 @@ _extract_pkg_filegroup = rule(
     attrs = {
         "src": attr.label(providers = [PackageFilegroupInfo, DefaultInfo]),
         "kind": attr.string(doc = "What part to extract", values = ["generic", "arch"]),
-    } | _PLAT_DETECTION_ATTRS,
+    } | OS_DETECTION_ATTRS,
 )
 
 _ZipInfo = provider(fields = {"zips_to_prefixes": "mapping of zip files to prefixes"})
@@ -181,7 +157,7 @@ _zip_info_filter = rule(
     attrs = {
         "srcs": attr.label_list(doc = "_ZipInfos to transform", providers = [_ZipInfo]),
         "kind": attr.string(doc = "Which zip kind to consider", values = ["generic", "arch"]),
-    } | _PLAT_DETECTION_ATTRS,
+    } | OS_DETECTION_ATTRS,
 )
 
 def _imported_zips_manifest_impl(ctx):

swift/rules.bzl

@@ -1,11 +1,106 @@
+load("//misc/bazel:os.bzl", "os_select")
+
+# TODO: make a shared library with the internal repos for transitions
+# unfortunately github.com/fmeum/rules_meta doesn't work any more with latest bazel
+
+def _transition_impl(settings, attr):
+    return {
+        "macos": {
+            "//command_line_option:copt": [
+                "-fno-rtti",
+                # we currently cannot built the swift extractor for ARM
+                "-arch",
+                "x86_64",
+            ],
+            "//command_line_option:cxxopt": [
+                "-std=c++20",
+                # we currently cannot built the swift extractor for ARM
+                "-arch",
+                "x86_64",
+            ],
+            "//command_line_option:linkopt": [
+                # we currently cannot built the swift extractor for ARM
+                "-arch",
+                "x86_64",
+            ],
+        },
+        "linux": {
+            "//command_line_option:copt": [
+                "-fno-rtti",
+            ],
+            "//command_line_option:cxxopt": [
+                "-std=c++20",
+            ],
+        },
+        "windows": {
+            "//command_line_option:cxxopt": [
+                "/std:c++20",
+                "--cxxopt=/Zc:preprocessor",
+            ],
+        },
+    }[attr.os]
+
+_transition = transition(
+    implementation = _transition_impl,
+    inputs = [],
+    outputs = ["//command_line_option:copt", "//command_line_option:cxxopt", "//command_line_option:linkopt"],
+)
+
+def _cc_transition_impl(ctx):
+    src = ctx.attr.src[0]
+    default_info = src[DefaultInfo]
+    executable = default_info.files_to_run.executable
+    runfiles = default_info.default_runfiles
+    direct = []
+    if executable:
+        original_executable = executable
+        executable = ctx.actions.declare_file(original_executable.basename)
+        command = "cp %s %s" % (original_executable.path, executable.path)
+
+        ctx.actions.run_shell(
+            inputs = [original_executable],
+            outputs = [executable],
+            command = command,
+        )
+
+        # costly, but no other way to remove the internal exe from the runfiles
+        files = runfiles.files.to_list()
+        files.remove(original_executable)
+        files.append(executable)
+        runfiles = ctx.runfiles(files)
+
+        direct = [executable]
+
+    providers = [
+        DefaultInfo(
+            files = depset(direct),
+            runfiles = runfiles,
+            executable = executable,
+        ),
+    ]
+    for p in (OutputGroupInfo, CcInfo):
+        if p in src:
+            providers.append(src[p])
+
+    return providers
+
+_cc_transition = rule(
+    implementation = _cc_transition_impl,
+    attrs = {
+        "_allowlist_function_transition": attr.label(
+            default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
+        ),
+        "src": attr.label(mandatory = True, cfg = _transition),
+        "os": attr.string(),
+    },
+)
+
 def _add_args(kwargs, kwarg, value):
     kwargs[kwarg] = kwargs.get(kwarg, []) + value
 
 def _wrap_cc(rule, kwargs):
-    _add_args(kwargs, "copts", [
-        # Required by LLVM/Swift
-        "-fno-rtti",
-    ])
+    name = kwargs.pop("name")
+    visibility = kwargs.pop("visibility", None)
     _add_args(kwargs, "features", [
         # temporary, before we do universal merging
         "-universal_binaries",
@@ -17,7 +112,13 @@ def _wrap_cc(rule, kwargs):
             "@platforms//os:macos": [],
             "//conditions:default": ["@platforms//:incompatible"],
         }))
-    rule(**kwargs)
+    rule(name = "internal/" + name, visibility = ["//visibility:private"], **kwargs)
+    _cc_transition(
+        name = name,
+        visibility = visibility,
+        src = ":internal/" + name,
+        os = os_select(linux = "linux", macos = "macos", windows = "windows"),
+    )
 
 def swift_cc_binary(**kwargs):
     _wrap_cc(native.cc_binary, kwargs)