[lldb] add de-duplication and working dir support for fmodule-file (#4039)

This PR adds correct handling of the `-fmodule-file=` flag. This
flag is of the form `-fmodule-file=[<name>=]<file>`, so we need
to split on the final = to get the path component in all cases.

Author: rmaz

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -1407,19 +1407,29 @@ bool ConsumeIncludeOption(StringRef &arg, StringRef &prefix) {
                                 "-isystem",
                                 "-isysroot",
                                 "-ivfsoverlay"};
+
   for (StringRef &option : options)
     if (arg.consume_front(option)) {
       prefix = option;
       return true;
     }
+
+  // We need special handling for -fmodule-file as we need to
+  // split on the final = after the module name.
+  if (arg.startswith("-fmodule-file=")) {
+    prefix = arg.substr(0, arg.rfind("=") + 1);
+    arg.consume_front(prefix);
+    return true;
+  }
+
   return false;
 }
 
 std::array<StringRef, 2> macro_flags = { "-D", "-U" };
 std::array<StringRef, 5> multi_arg_flags =
     { "-D", "-U", "-I", "-F", "-working-directory" };
-std::array<StringRef, 5> args_to_unique =
-    { "-D", "-U", "-I", "-F", "-fmodule-map-file=" };
+std::array<StringRef, 6> args_to_unique = {
+    "-D", "-U", "-I", "-F", "-fmodule-file=", "-fmodule-map-file="};
 
 bool IsMultiArgClangFlag(StringRef arg) {
   for (auto &flag : multi_arg_flags)
@@ -7358,8 +7368,8 @@ CompilerType SwiftASTContext::GetUnboundGenericType(opaque_compiler_type_t type,
     auto *nominal_type_decl = unbound_generic_type->getDecl();
     swift::GenericSignature generic_sig =
         nominal_type_decl->getGenericSignature();
-    swift::TypeArrayView<swift::GenericTypeParamType> depView 
-        = generic_sig.getGenericParams();
+    swift::TypeArrayView<swift::GenericTypeParamType> depView =
+        generic_sig.getGenericParams();
     swift::Type depTy = depView[idx];
     return ToCompilerType({nominal_type_decl->mapTypeIntoContext(depTy)
                                ->castTo<swift::ArchetypeType>()});

lldb/unittests/Symbol/TestSwiftASTContext.cpp

@@ -268,19 +268,82 @@ TEST_F(TestSwiftASTContext, ApplyWorkingDir) {
   EXPECT_EQ(
       single_arg_rel_path,
       llvm::SmallString<128>("-fmodule-map-file=rel/dir/module.modulemap"));
+
+  // fmodule-file needs to handle different cases:
+  //  -fmodule-file=path/to/pcm
+  //  -fmodule-file=name=path/to/pcm
+  llvm::SmallString<128> module_file_abs_path(
+      "-fmodule-file=/some/dir/module.pcm");
+  SwiftASTContext::ApplyWorkingDir(module_file_abs_path, abs_working_dir);
+  EXPECT_EQ(module_file_abs_path,
+            llvm::SmallString<128>("-fmodule-file=/some/dir/module.pcm"));
+
+  llvm::SmallString<128> module_file_rel_path(
+      "-fmodule-file=relpath/module.pcm");
+  SwiftASTContext::ApplyWorkingDir(module_file_rel_path, abs_working_dir);
+  EXPECT_EQ(
+      module_file_rel_path,
+      llvm::SmallString<128>("-fmodule-file=/abs/dir/relpath/module.pcm"));
+
+  llvm::SmallString<128> module_file_with_name_abs_path(
+      "-fmodule-file=modulename=/some/dir/module.pcm");
+  SwiftASTContext::ApplyWorkingDir(module_file_with_name_abs_path,
+                                   abs_working_dir);
+  EXPECT_EQ(
+      module_file_with_name_abs_path,
+      llvm::SmallString<128>("-fmodule-file=modulename=/some/dir/module.pcm"));
+
+  llvm::SmallString<128> module_file_with_name_rel_path(
+      "-fmodule-file=modulename=relpath/module.pcm");
+  SwiftASTContext::ApplyWorkingDir(module_file_with_name_rel_path,
+                                   abs_working_dir);
+  EXPECT_EQ(module_file_with_name_rel_path,
+            llvm::SmallString<128>(
+                "-fmodule-file=modulename=/abs/dir/relpath/module.pcm"));
 }
 
 namespace {
-  const std::vector<std::string> duplicated_flags = {
-    "-DMACRO1", "-D", "MACRO1", "-UMACRO2", "-U", "MACRO2",
-    "-I/path1", "-I", "/path1", "-F/path2", "-F", "/path2",
-    "-fmodule-map-file=/path3", "-fmodule-map-file=/path3",
-    "-F/path2", "-F", "/path2", "-I/path1", "-I", "/path1",
-    "-UMACRO2", "-U", "MACRO2", "-DMACRO1", "-D", "MACRO1",
-  };
-  const std::vector<std::string> uniqued_flags = {
-    "-DMACRO1", "-UMACRO2", "-I/path1", "-F/path2", "-fmodule-map-file=/path3"
-  };
+const std::vector<std::string> duplicated_flags = {
+    "-DMACRO1",
+    "-D",
+    "MACRO1",
+    "-UMACRO2",
+    "-U",
+    "MACRO2",
+    "-I/path1",
+    "-I",
+    "/path1",
+    "-F/path2",
+    "-F",
+    "/path2",
+    "-fmodule-map-file=/path3",
+    "-fmodule-map-file=/path3",
+    "-F/path2",
+    "-F",
+    "/path2",
+    "-I/path1",
+    "-I",
+    "/path1",
+    "-UMACRO2",
+    "-U",
+    "MACRO2",
+    "-DMACRO1",
+    "-D",
+    "MACRO1",
+    "-fmodule-file=/path/to/pcm",
+    "-fmodule-file=/path/to/pcm",
+    "-fmodule-file=modulename=/path/to/pcm",
+    "-fmodule-file=modulename=/path/to/pcm",
+};
+const std::vector<std::string> uniqued_flags = {
+    "-DMACRO1",
+    "-UMACRO2",
+    "-I/path1",
+    "-F/path2",
+    "-fmodule-map-file=/path3",
+    "-fmodule-file=/path/to/pcm",
+    "-fmodule-file=modulename=/path/to/pcm",
+};
 } // namespace
 
 TEST(ClangArgs, UniquingCollisionWithExistingFlags) {