Swift: enable dynamic mode

Providing `--dynamic_mode=fully` (for example setting it in
`local.bazelrc`) will now work.

All runfiles are now copied in the extractor pack: in dynamic mode,
those will be the executable and the dynamic libraries, while in static
mode only the executable will be part of the runfiles.

Setting the correct `LD_LIBRARY_PATH` in `qltest.sh` then allows to
run tests with this pakcage. If we need something more, we can switch to
a wrapper script in place of `extractor` in the future.

Notice that `LD_LIBRARY_PATH` is also set in static mode, but that has
no consequence.

.gitignore

@@ -37,5 +37,8 @@ csharp/extractor/Semmle.Extraction.CSharp.Driver/Properties/launchSettings.json
 # links created by bazel
 /bazel-*
 
+# local bazel options
+/local.bazelrc
+
 # CLion project files
 /.clwb

misc/bazel/pkg_runfiles.bzl

@@ -0,0 +1,33 @@
+load("@rules_pkg//:mappings.bzl", "pkg_attributes", "pkg_files")
+
+def _runfiles_group_impl(ctx):
+    files = []
+    for src in ctx.attr.srcs:
+        rf = src[DefaultInfo].default_runfiles
+        if rf != None:
+            files.append(rf.files)
+    return [
+        DefaultInfo(
+            files = depset(transitive = files),
+        ),
+    ]
+
+_runfiles_group = rule(
+    implementation = _runfiles_group_impl,
+    attrs = {
+        "srcs": attr.label_list(),
+    },
+)
+
+def pkg_runfiles(*, name, srcs, **kwargs):
+    internal_name = "_%s_runfiles" % name
+    _runfiles_group(
+        name = internal_name,
+        srcs = srcs,
+    )
+    kwargs.setdefault("attributes", pkg_attributes(mode = "0755"))
+    pkg_files(
+        name = name,
+        srcs = [internal_name],
+        **kwargs
+    )

misc/bazel/workspace.bzl

@@ -22,7 +22,7 @@ def codeql_workspace(repository_name = "codeql"):
                 _swift_prebuilt_version,
                 repo_arch,
             ),
-            build_file = "@%s//swift/extractor:BUILD.swift-prebuilt.bazel" % repository_name,
+            build_file = "@%s//swift/tools/prebuilt:BUILD.swift-prebuilt.bazel" % repository_name,
             sha256 = sha256,
         )
 
@@ -55,4 +55,3 @@ def codeql_workspace(repository_name = "codeql"):
             "https://github.com/bazelbuild/rules_python/archive/refs/tags/0.8.1.tar.gz",
         ],
     )
-

swift/BUILD.bazel

@@ -1,6 +1,7 @@
 load("@rules_pkg//:mappings.bzl", "pkg_attributes", "pkg_filegroup", "pkg_files", "strip_prefix")
 load("@rules_pkg//:install.bzl", "pkg_install")
 load("//:defs.bzl", "codeql_platform")
+load("//misc/bazel:pkg_runfiles.bzl", "pkg_runfiles")
 
 filegroup(
     name = "dbscheme",
@@ -45,24 +46,15 @@ pkg_filegroup(
     visibility = ["//visibility:public"],
 )
 
-pkg_files(
+pkg_runfiles(
     name = "extractor",
     srcs = ["//swift/extractor"],
-    attributes = pkg_attributes(mode = "0755"),
     prefix = "tools/" + codeql_platform,
 )
 
-alias(
-    name = "swift-test-sdk",
-    actual = select({
-        "@bazel_tools//src/conditions:%s" % arch: "@swift_prebuilt_%s//:swift-test-sdk" % arch
-        for arch in ("linux", "darwin_x86_64", "darwin_arm64")
-    }),
-)
-
 pkg_files(
     name = "swift-test-sdk-arch",
-    srcs = [":swift-test-sdk"],
+    srcs = ["//swift/tools/prebuilt:swift-test-sdk"],
     prefix = "qltest/" + codeql_platform,
     strip_prefix = strip_prefix.from_pkg(),
 )

swift/extractor/BUILD.bazel

@@ -1,13 +1,5 @@
 load("//swift:rules.bzl", "swift_cc_binary")
 
-alias(
-    name = "swift-llvm-support",
-    actual = select({
-        "@bazel_tools//src/conditions:%s" % arch: "@swift_prebuilt_%s//:swift-llvm-support" % arch
-        for arch in ("linux", "darwin_x86_64", "darwin_arm64")
-    }),
-)
-
 swift_cc_binary(
     name = "extractor",
     srcs = [
@@ -18,7 +10,7 @@ swift_cc_binary(
     ],
     visibility = ["//swift:__pkg__"],
     deps = [
-        ":swift-llvm-support",
+        "//swift/tools/prebuilt:swift-llvm-support",
         "//swift/extractor/trap",
     ],
 )

swift/tools/prebuilt/BUILD.bazel

@@ -0,0 +1,11 @@
+package(default_visibility = ["//swift:__subpackages__"])
+
+[
+    alias(
+        name = name,
+        actual = select({
+            "@bazel_tools//src/conditions:%s" % arch: "@swift_prebuilt_%s//:%s" % (arch, name)
+            for arch in ("linux", "darwin_x86_64", "darwin_arm64")
+        }),
+    ) for name in ("swift-llvm-support", "swift-test-sdk")
+]

swift/tools/qltest.sh

@@ -4,4 +4,6 @@ mkdir -p "$CODEQL_EXTRACTOR_SWIFT_TRAP_DIR"
 
 QLTEST_LOG="$CODEQL_EXTRACTOR_SWIFT_LOG_DIR"/qltest.log
 
+export LD_LIBRARY_PATH="$CODEQL_EXTRACTOR_SWIFT_ROOT/tools/$CODEQL_PLATFORM"
+
 exec "$CODEQL_EXTRACTOR_SWIFT_ROOT/tools/$CODEQL_PLATFORM/extractor" -sdk "$CODEQL_EXTRACTOR_SWIFT_ROOT/qltest/$CODEQL_PLATFORM/sdk" -c *.swift >> $QLTEST_LOG 2>&1