DependenciesScanner: move -fapinotes-swift-version to extra PCM arguments

Swift interface files may specify the effective language version to use. When building
a PCM loadable for these textual interface files, we should respect the language
version. This patch moves -fapinotes-swift-version from the generic PCM
commands to the extra PCM arguments owned by each loading Swift module.

Author: nkcsgexi

lib/ClangImporter/ClangModuleDependencyScanner.cpp

@@ -231,14 +231,19 @@ void ClangImporter::recordModuleDependencies(
     // Add all args inheritted from creating the importer.
     auto It = allArgs.begin();
     while(It != allArgs.end()) {
+      StringRef arg = *It;
       // Remove the -target arguments because we should use the target triple
       // from the depending Swift modules.
-      if (*It == "-target") {
+      if (arg == "-target") {
         It += 2;
-        continue;
+      } else if (arg.startswith("-fapinotes-swift-version=")) {
+        // Remove the apinotes version because we should use the language version
+        // specified in the interface file.
+        It += 1;
+      } else {
+        addClangArg(*It);
+        ++ It;
       }
-      addClangArg(*It);
-      ++ It;
     }
 
     // Swift frontend action: -emit-pcm

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -1050,6 +1050,13 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
     GenericArgs.push_back(triple);
   }
 
+  // Inherit the Swift language version
+  subInvocation.getLangOptions().EffectiveLanguageVersion =
+    LangOpts.EffectiveLanguageVersion;
+  GenericArgs.push_back("-swift-version");
+  GenericArgs.push_back(ArgSaver.save(subInvocation.getLangOptions()
+    .EffectiveLanguageVersion.asAPINotesVersionString()));
+
   subInvocation.setImportSearchPaths(SearchPathOpts.ImportSearchPaths);
   llvm::for_each(SearchPathOpts.ImportSearchPaths,
                  [&](const std::string &path) {
@@ -1400,9 +1407,15 @@ bool InterfaceSubContextDelegateImpl::runInSubCompilerInstance(StringRef moduleN
   }
   info.BuildArguments = BuildArgs;
   info.Hash = CacheHash;
-  std::array<StringRef, 4> ExtraPCMArgs = {"-Xcc", "-target", "-Xcc",
-    // PCMs should use the target tripe the interface will be using to build
-    *(std::find(BuildArgs.rbegin(), BuildArgs.rend(), "-target") - 1)};
+  auto target =  *(std::find(BuildArgs.rbegin(), BuildArgs.rend(), "-target") - 1);
+  auto langVersion = *(std::find(BuildArgs.rbegin(), BuildArgs.rend(),
+                                 "-swift-version") - 1);
+  std::array<StringRef, 6> ExtraPCMArgs = {
+    // PCMs should use the target triple the interface will be using to build
+    "-Xcc", "-target", "-Xcc", target,
+    // PCMs should use the effective Swift language version for apinotes.
+    "-Xcc", ArgSaver.save((llvm::Twine("-fapinotes-swift-version=") + langVersion).str())
+  };
   info.ExtraPCMArgs = ExtraPCMArgs;
   // Run the action under the sub compiler instance.
   return action(info);

lib/FrontendTool/ScanDependencies.cpp

@@ -426,10 +426,15 @@ bool swift::scanDependencies(CompilerInstance &instance) {
   llvm::SmallString<32> mainModulePath = mainModule->getName().str();
   llvm::sys::path::replace_extension(mainModulePath, newExt);
 
+  std::string apinotesVer = (llvm::Twine("-fapinotes-swift-version=")
+    + instance.getASTContext().LangOpts.EffectiveLanguageVersion
+      .asAPINotesVersionString()).str();
   // Compute the dependencies of the main module.
   auto mainDependencies =
     ModuleDependencies::forMainSwiftModule(mainModulePath.str().str(), {
-      "-Xcc", "-target", "-Xcc", instance.getASTContext().LangOpts.Target.str()
+      // ExtraPCMArgs
+      "-Xcc", "-target", "-Xcc", instance.getASTContext().LangOpts.Target.str(),
+      "-Xcc", apinotesVer
     });
   {
     llvm::StringSet<> alreadyAddedModules;

test/ScanDependencies/module_deps.swift

@@ -66,6 +66,7 @@ import SubE
 // CHECK-NEXT:    "-Xcc",
 // CHECK-NEXT:    "-target",
 // CHECK-NEXT:    "-Xcc",
+// CHECK:         "-fapinotes-swift-version=4"
 
 // CHECK: "bridgingHeader":
 // CHECK-NEXT: "path":
@@ -134,7 +135,11 @@ import SubE
 // CHECK: "G"
 // CHECK: "-swift-version"
 // CHECK: "5"
-// CHECK: ]
+// CHECK: ],
+// CHECK" "extraPcmArgs": [
+// CHECK"   "-target",
+// CHECK"   "-fapinotes-swift-version=5"
+// CHECK" ]
 
 /// --------Swift module Swift
 // CHECK-LABEL: "modulePath": "Swift.swiftmodule",