Swift: fetch prebuilt swift and link against it

This is known to break linux integration in sembuild.

misc/bazel/workspace.bzl

@@ -2,6 +2,17 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
 
 def codeql_workspace():
+    for arch, repo_arch, sha256 in (
+        ("linux", "linux", "48e39228e49aa560f0c1e504c4f9d488e28278b31fedc8271ce4cf807d9f7791"),
+        ("darwin_x86_64", "macos-x86_64", "8f1e8e9cfb4391b3fbc0b90da548a7e660f302b1a8551e6640e8a944eb377028"),
+    ):
+        http_archive(
+            name = "swift_prebuilt_%s" % arch,
+            url = "https://github.com/dsp-testing/codeql-swift-artifacts/releases/download/swift-5.6-RELEASE.42271.49/swift-prebuilt-%s.zip" % repo_arch,
+            build_file = "@ql//swift/extractor:BUILD.swift-prebuilt.bazel",
+            sha256 = sha256,
+        )
+
     maybe(
         repo_rule = http_archive,
         name = "rules_pkg",

swift/extractor/BUILD.bazel

@@ -1,3 +1,11 @@
+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")
+    }),
+)
+
 cc_binary(
     name = "extractor",
     srcs = ["main.cpp"],
@@ -7,4 +15,5 @@ cc_binary(
         "//conditions:default": ["@platforms//:incompatible"],
     }),
     visibility = ["//swift:__pkg__"],
+    deps = [":swift-llvm-support"],
 )

swift/extractor/BUILD.swift-prebuilt.bazel

@@ -0,0 +1,23 @@
+cc_library(
+    name = "swift-llvm-support",
+    srcs = glob([
+        "libswiftAndLlvmSupportReal.a",
+        "libswiftAndLlvmSupportReal.so",
+    ]),
+    hdrs = glob(["include/**/*"]),
+    linkopts = [
+        "-lm",
+        "-lz",
+    ] + select({
+        "@platforms//os:macos": ["-lcurses"],
+        "@platforms//os:linux": [
+            "-luuid",
+            "-lrt",
+            "-lpthread",
+            "-ltinfo",
+            "-ldl",
+        ],
+    }),
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+)

swift/extractor/main.cpp

@@ -2,7 +2,10 @@
 #include <iomanip>
 #include <stdlib.h>
 
-int main() {
+#include <swift/Basic/LLVMInitialize.h>
+
+int main(int argc, char** argv) {
+  PROGRAM_START(argc, argv);
   if (auto trapDir = getenv("CODEQL_EXTRACTOR_SWIFT_TRAP_DIR")) {
     std::string file = trapDir;
     file += "/my_first.trap";