[Serialization] Load indirect package dependencies from the current package

When loading a swiftmodule A, read its package information to tell if
the current client should load A's dependencies imports by a package
import. Only clients belonging to the same package as A should load
those dependencies, clients outside of the package likely don't have
access to those dependencies.

This is specific to swiftmodules as swiftinterfaces never display a
package-only import. Clients are unaware of package dependencies when
building against a swiftinterface.

rdar://106164813

Author: xymus

lib/Serialization/ModuleFile.cpp

@@ -209,6 +209,10 @@ Status ModuleFile::associateWithFileContext(FileUnit *file, SourceLoc diagLoc,
       continue;
     }
 
+    if (dependency.isPackageOnly() &&
+        ctx.LangOpts.PackageName != this->getModulePackageName())
+      continue;
+
     ImportPath::Builder builder(ctx, dependency.Core.RawPath,
                                 /*separator=*/'\0');
     for (const auto &elem : builder) {

lib/Serialization/ModuleFile.h

@@ -107,6 +107,9 @@ class ModuleFile
     bool isImplementationOnly() const {
       return Core.isImplementationOnly();
     }
+    bool isPackageOnly() const {
+      return Core.isPackageOnly();
+    }
 
     bool isHeader() const { return Core.isHeader(); }
     bool isScoped() const { return Core.isScoped(); }

lib/Serialization/ModuleFileSharedCore.h

@@ -150,6 +150,9 @@ class ModuleFileSharedCore {
     bool isImplementationOnly() const {
       return getImportControl() == ImportFilterKind::ImplementationOnly;
     }
+    bool isPackageOnly() const {
+      return getImportControl() == ImportFilterKind::PackageOnly;
+    }
 
     bool isHeader() const { return IsHeader; }
     bool isScoped() const { return IsScoped; }
@@ -557,6 +560,10 @@ class ModuleFileSharedCore {
     return Name;
   }
 
+  StringRef getModulePackageName() const {
+    return ModulePackageName;
+  }
+
   /// Returns the list of modules this module depends on.
   ArrayRef<Dependency> getDependencies() const {
     return Dependencies;

lib/Serialization/SerializedModuleLoader.cpp

@@ -426,6 +426,10 @@ llvm::ErrorOr<ModuleDependencyInfo> SerializedModuleLoaderBase::scanModuleFile(
     if (dependency.isImplementationOnly())
       continue;
 
+    if (dependency.isPackageOnly() &&
+        Ctx.LangOpts.PackageName != loadedModuleFile->getModulePackageName())
+      continue;
+
     // Find the top-level module name.
     auto modulePathStr = dependency.getPrettyPrintedPath();
     StringRef moduleName = modulePathStr;