remove module prefix from swiftinterface types

Summary: Add a workaround for swiftlang/swift#56573 where we strip the module prefix for first party modules from types in swiftinterface files. This should give us the same type lookup logic as when compiling from source.

Reviewed By: NuriAmari

Differential Revision: D67802092

fbshipit-source-id: f074d8dfa816db20c6640ad53f93d227e70360db

prelude/apple/swift/swift_compilation.bzl

@@ -486,6 +486,7 @@ def _compile_swiftmodule(
             "-emit-module-interface",
             "-emit-module-interface-path",
             output_swiftinterface.as_output(),
+            "-remove-module-prefixes",
         ])
         _compile_with_argsfile(ctx, "emit_swiftinterface", ".swiftinterface", swiftinterface_argsfile, srcs, swiftinterface_cmd, toolchain, num_threads = 1)
 

prelude/apple/tools/swift_exec.py

@@ -6,14 +6,88 @@
 # License, Version 2.0 found in the LICENSE-APACHE file in the root directory
 # of this source tree.
 
+import json
 import os
+import re
 import subprocess
 import sys
 
 _RE_TMPDIR_ENV_VAR = "TMPDIR"
 _FILE_WRITE_FAILURE_MARKER = "could not write"
 
 
+def _expand_args(command):
+    for arg in command:
+        if arg.startswith("@"):
+            with open(arg[1:]) as argsfile:
+                return [line.rstrip() for line in argsfile.readlines()]
+
+    return []
+
+
+def _get_modulemap(args):
+    for i in range(len(args)):
+        if args[i].startswith("-explicit-swift-module-map-file"):
+            if args[i + 1].startswith("-Xfrontend"):
+                path = args[i + 2]
+            else:
+                path = args[i + 1]
+
+            with open(path.strip()) as modulemap:
+                return json.load(modulemap)
+
+    return None
+
+
+def _get_modulename(args):
+    return args[args.index("-module-name") + 1]
+
+
+def _get_modules(command):
+    args = _expand_args(command)
+    modulemap = _get_modulemap(args)
+    if modulemap is None:
+        return set()
+
+    modules = set()
+    for entry in modulemap:
+        # We only remove prefixes from first party modules.
+        if "sdk_deps" in entry.get("clangModulePath", ""):
+            pass
+        elif "sdk_deps" in entry.get("modulePath", ""):
+            pass
+        else:
+            modules.add(entry["moduleName"])
+
+    modules.add(_get_modulename(args))
+
+    return modules
+
+
+def _remove_swiftinterface_module_prefixes(command):
+    interface_path = command[command.index("-emit-module-interface-path") + 1]
+    modules = _get_modules(command)
+    if len(modules) == 0:
+        return
+
+    with open(interface_path) as f:
+        interface = f.read()
+
+    output = []
+    pattern = re.compile(r"(\w+)\.(\w+)")
+    for line in interface.splitlines():
+        outline = line
+        for m in pattern.finditer(line):
+            if m.group(1) in modules:
+                outline = outline.replace(m.group(0), m.group(2))
+
+        output.append(outline)
+
+    with open(interface_path, "w") as f:
+        f.write("\n".join(output))
+        f.write("\n")
+
+
 def main():
     env = os.environ.copy()
     if "INSIDE_RE_WORKER" in env and _RE_TMPDIR_ENV_VAR in env:
@@ -35,6 +109,11 @@ def main():
 
     command = sys.argv[1:]
 
+    # Check if we need to strip module prefixes from types in swiftinterface output.
+    should_remove_module_prefixes = "-remove-module-prefixes" in command
+    if should_remove_module_prefixes:
+        command.remove("-remove-module-prefixes")
+
     # Use relative paths for debug information and index information,
     # so we generate relocatable files.
     #
@@ -79,6 +158,10 @@ def main():
             )
             sys.exit(1)
 
+    # https://github.com/swiftlang/swift/issues/56573
+    if should_remove_module_prefixes:
+        _remove_swiftinterface_module_prefixes(command)
+
     sys.exit(result.returncode)