Fix full LTO in standalone and Linux builds

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot-Session: a52f212e-fee3-4245-a5fc-e5be4cdf2cdf

Author: paldepind

misc/bazel/rust.bzl

@@ -1,7 +1,7 @@
 load("@rules_rust//rust:defs.bzl", "rust_binary")
 load("@semmle_code//buildutils-internal:glibc_symbols_check.bzl", "glibc_symbols_check")
 load("@semmle_code//buildutils-internal:lipo.bzl", "universal_binary")
-load("@semmle_code//buildutils-internal:transitions.bzl", "forward_binary_from_transition", "get_transition_attrs")
+load("//misc/bazel:transitions.bzl", "forward_binary_from_transition", "get_transition_attrs")
 
 def _full_lto_transition_impl(_settings, _attr):
     return {"@rules_rust//rust/settings:lto": "fat"}
@@ -27,6 +27,9 @@ def codeql_rust_binary(
     rust_label_name = "single_arch/" + name
     binary_dep = ":" + rust_label_name
     if full_lto:
+        # rustc must consume the LLVM bitcode because the C++ linker may use an
+        # incompatible LLVM version.
+        kwargs["experimental_use_cc_common_link"] = 0
         lto_label_name = "full_lto/" + name
         _full_lto_binary(
             name = lto_label_name,

misc/bazel/transitions.bzl

@@ -0,0 +1,47 @@
+load("@bazel_skylib//lib:paths.bzl", "paths")
+
+def forward_binary_from_transition(ctx):
+    binary = ctx.attr.dep[0]
+    default_info = binary[DefaultInfo]
+    original_executable = default_info.files_to_run.executable
+    if not original_executable:
+        fail("Cannot transition a target that is not executable")
+
+    (_, extension) = paths.split_extension(original_executable.basename)
+    new_executable = ctx.actions.declare_file(ctx.label.name + extension)
+    inputs = [original_executable]
+    command = "cp %s %s" % (original_executable.path, new_executable.path)
+
+    providers = []
+    if OutputGroupInfo in binary:
+        pdb_file = getattr(binary[OutputGroupInfo], "pdb_file", None)
+        if pdb_file:
+            (pdb_file,) = pdb_file.to_list()
+            linked_pdb_file = ctx.actions.declare_file(ctx.label.name + ".pdb")
+            ctx.actions.symlink(target_file = pdb_file, output = linked_pdb_file)
+            inputs.append(linked_pdb_file)
+        providers.append(binary[OutputGroupInfo])
+
+    ctx.actions.run_shell(
+        inputs = inputs,
+        outputs = [new_executable],
+        command = command,
+    )
+    files = depset(direct = [new_executable])
+    runfiles = default_info.default_runfiles.merge(ctx.runfiles([new_executable]))
+    providers.append(
+        DefaultInfo(
+            files = files,
+            runfiles = runfiles,
+            executable = new_executable,
+        ),
+    )
+    return providers
+
+def get_transition_attrs(transition_rule):
+    return {
+        "_allowlist_function_transition": attr.label(
+            default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
+        ),
+        "dep": attr.label(mandatory = True, cfg = transition_rule),
+    }