bazel: Use linkopts instead of srcs for consuming archives

This should fix the build on Debian 10 with LLVM 11.

- Keep order of files to look up in `ls` invocation
- Use `--start-group`/`--end-group` linker options
- Drive-by: use `splitlines()` instead of manual `split("\n")[:-1]`

PiperOrigin-RevId: 439248079
Change-Id: I919bb292ac8a5f514431aa004345f1c6478b1cc9

sandboxed_api/bazel/llvm_config.bzl

@@ -16,7 +16,7 @@
 
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
 
-SYSTEM_LLVM_BAZEL = """package(default_visibility = ["//visibility:public"])
+SYSTEM_LLVM_BAZEL_TEMPLATE = """package(default_visibility = ["//visibility:public"])
 # Create one hidden library with all LLVM headers that depends on all its
 # static library archives. This will be used to provide individual library
 # targets named the same as the upstream Bazel files.
@@ -32,12 +32,15 @@ cc_library(
  "llvm-project-include/llvm/**/*.h",
  "llvm-project-include/llvm/**/*.inc",
  ]),
- linkopts = ["-lncurses"],
  includes = ["llvm-project-include"],
- srcs = glob([
- "llvm-project-lib/libLLVM*.a",
- "llvm-project-lib/libclang*.a",
- ]),
+ linkopts = [
+ "-lncurses",
+ "-lz",
+ "-L%{llvm_lib_dir}",
+ "-Wl,--start-group",
+ %{llvm_libs}
+ "-Wl,--end-group",
+ ],
  visibility = ["@llvm-project//clang:__pkg__"],
 )
 # Fake support library
@@ -60,14 +63,14 @@ def _use_system_llvm(ctx):
 
  # Look for LLVM in known places
  llvm_dirs = ctx.execute(
- ["ls", "-1"] +
+ ["ls", "-1f"] +
  [
  "/usr/lib/llvm-{}/include/llvm/Support/InitLLVM.h".format(ver)
  for ver in [16, 15, 14, 13, 12, 11] # Debian
  ] + [
  "/usr/include/llvm/Support/InitLLVM.h", # Fedora and others
  ],
- ).stdout.split("\n")[:-1]
+ ).stdout.splitlines()
  if llvm_dirs:
  llvm_dir = llvm_dirs[0].split("/include/llvm/")[0]
  for suffix in ["llvm", "llvm-c", "clang", "clang-c"]:
@@ -78,16 +81,28 @@ def _use_system_llvm(ctx):
 
  # Try to find the lib directory
  lib_dirs = ctx.execute(
- ["ls", "-d", "-1"] +
+ ["ls", "-d1f"] +
  [llvm_dir + "/lib64", llvm_dir + "/lib"],
- ).stdout.split("\n")[:-1]
+ ).stdout.splitlines()
  if lib_dirs:
- ctx.symlink(lib_dirs[0], "llvm/llvm-project-lib")
  found = True
 
  if found:
  # Create stub targets in sub-packages
- ctx.file("llvm/BUILD.bazel", SYSTEM_LLVM_BAZEL)
+ lib_dir = lib_dirs[0] # buildifier: disable=uninitialized
+ archives = ctx.execute(
+ ["find", ".", "-maxdepth", "1"] +
+ ["(", "-name", "libLLVM*.a", "-o", "-name", "libclang*.a", ")"],
+ working_directory = lib_dir,
+ ).stdout.splitlines()
+ lib_strs = sorted(["\"-l{}\",".format(a[5:-2]) for a in archives])
+
+ ctx.file(
+ "llvm/BUILD.bazel",
+ SYSTEM_LLVM_BAZEL_TEMPLATE
+ .replace("%{llvm_lib_dir}", lib_dir)
+ .replace("%{llvm_libs}", "\n".join(lib_strs)),
+ )
  ctx.file("clang/BUILD.bazel", SYSTEM_CLANG_BAZEL)
  return found