Allow specifying a custom generated header name

swift/internal/api.bzl

@@ -498,6 +498,7 @@ def _compile(
         copts = [],
         defines = [],
         deps = [],
+        generated_header_name = None,
         genfiles_dir = None):
     """Compiles a Swift module.
 
@@ -530,6 +531,8 @@ def _compile(
         deps: Dependencies of the target being compiled. These targets must
             propagate one of the following providers: `CcInfo`, `SwiftInfo`, or
             `apple_common.Objc`.
+        generated_header_name: The name of the generated Objective-C interface header.
+            If not provided, it defaults to `${target_name}-Swift.h`.
         genfiles_dir: The Bazel `*-genfiles` directory root. If provided, its
             path is added to ClangImporter's header search paths for
             compatibility with Bazel's C++ and Objective-C rules which support
@@ -705,6 +708,7 @@ def _compile(
         generated_header = derived_files.objc_header(
             actions = actions,
             target_name = target_name,
+            header_name = generated_header_name,
         )
         args.add("-emit-objc-header-path")
         args.add(generated_header)
@@ -1035,6 +1039,12 @@ explicitly called by code in the binary; for example, if you rely on runtime
 checks for protocol conformances added in extensions in the library but do not
 directly reference any other symbols in the object file that adds that
 conformance.
+""",
+            ),
+            "generated_header_name": attr.string(
+                doc = """\
+The name of the generated Objective-C interface header.
+If not provided, it defaults to `${target_name}-Swift.h`.
 """,
             ),
         },

swift/internal/derived_files.bzl

@@ -122,17 +122,28 @@ def _modulewrap_object(actions, target_name):
     """
     return actions.declare_file("{}.modulewrap.o".format(target_name))
 
-def _objc_header(actions, target_name):
+def _objc_header(actions, target_name, header_name = None):
     """Declares the generated header file exposing Swift APIs to Objective-C.
 
     Args:
         actions: The context's actions object.
         target_name: The name of the target being built.
+        header_name: The name of the header being declared.
 
     Returns:
         The declared `File`.
     """
-    return actions.declare_file("{}-Swift.h".format(target_name))
+    if header_name:
+        if not header_name.endswith(".h"):
+            fail(("The generated objc header name for {} must end in" +
+                  " '.h', given '{}'") % (target_name, header_name))
+        if "/" in header_name:
+            fail(("The generated objc header name for {} cannot contain a " +
+                  "'/', given '{}'") % (target_name, header_name))
+    else:
+        header_name = "{}-Swift.h".format(target_name)
+
+    return actions.declare_file(header_name)
 
 def _partial_swiftmodule(actions, target_name, src):
     """Declares a file for a partial Swift module created during compilation.

swift/internal/swift_library.bzl

@@ -157,6 +157,7 @@ def _swift_library_impl(ctx):
         defines = ctx.attr.defines,
         deps = deps + private_deps,
         feature_configuration = feature_configuration,
+        generated_header_name = ctx.attr.generated_header_name,
         genfiles_dir = ctx.genfiles_dir,
         module_name = module_name,
         srcs = srcs,