[Serialization] Restrict loading swiftmodule files to the builder's SDK

Serialize the canonical name of the SDK used when building a swiftmodule
file and use it to ensure that the swiftmodule file is loaded only with
the same SDK. The SDK name must be passed down from the frontend.

This will report unsupported configurations like:

- Installing roots between incompatible SDKs without deleting the
swiftmodule files.
- Having multiple targets in the same project using different SDKs.
- Loading a swiftmodule created with a newer SDK (and stdlib) with an
older SDK.

All of these lead to hard to investigate deserialization failures and
this change should detect them early, before reaching a deserialization
failure.

rdar://78048939

Author: xymus

include/swift/AST/DiagnosticsSema.def

@@ -782,6 +782,9 @@ ERROR(serialization_name_mismatch_repl,none,
 ERROR(serialization_target_incompatible,Fatal,
       "module %0 was created for incompatible target %1: %2",
       (Identifier, StringRef, StringRef))
+ERROR(serialization_sdk_mismatch,Fatal,
+      "cannot load module %0 built with SDK '%1' when using SDK '%2': %3",
+      (Identifier, StringRef, StringRef, StringRef))
 ERROR(serialization_target_incompatible_repl,none,
       "module %0 was created for incompatible target %1: %2",
       (Identifier, StringRef, StringRef))

include/swift/AST/SearchPathOptions.h

@@ -82,6 +82,10 @@ class SearchPathOptions {
   /// would for a non-system header.
   bool DisableModulesValidateSystemDependencies = false;
 
+  /// Enforce loading only serialized modules built with the same SDK
+  /// as the context loading it.
+  bool EnableSameSDKCheck = true;
+
   /// A set of compiled modules that may be ready to use.
   std::vector<std::string> CandidateCompiledModules;
 

include/swift/Basic/LangOptions.h

@@ -127,6 +127,9 @@ namespace swift {
     /// The target variant SDK version, if known.
     Optional<llvm::VersionTuple> VariantSDKVersion;
 
+    /// The SDK canonical name, if known.
+    std::string SDKName;
+
     /// The alternate name to use for the entry point instead of main.
     std::string entryPointFunctionName = "main";
 

include/swift/Option/FrontendOptions.td

@@ -823,6 +823,9 @@ def target_sdk_version : Separate<["-"], "target-sdk-version">,
 def target_variant_sdk_version : Separate<["-"], "target-variant-sdk-version">,
   HelpText<"The version of target variant SDK used for compilation">;
 
+def target_sdk_name : Separate<["-"], "target-sdk-name">,
+  HelpText<"Canonical name of the target SDK used for compilation">;
+
 def extra_clang_options_only : Flag<["-"], "only-use-extra-clang-opts">,
   HelpText<"Options passed via -Xcc are sufficient for Clang configuration">;
 

include/swift/Serialization/SerializationOptions.h

@@ -35,6 +35,7 @@ namespace swift {
     bool SkipSymbolGraphInheritedDocs = true;
     bool IncludeSPISymbolsInSymbolGraph = false;
     llvm::VersionTuple UserModuleVersion;
+    std::string SDKName;
 
     StringRef GroupInfoPath;
     StringRef ImportedHeader;

include/swift/Serialization/Validation.h

@@ -66,7 +66,11 @@ enum class Status {
   TargetIncompatible,
 
   /// The module file was built for a target newer than the current target.
-  TargetTooNew
+  TargetTooNew,
+
+  /// The module file was built with a different SDK than the one in use
+  /// to build the client.
+  SDKMismatch
 };
 
 /// Returns true if the data looks like it contains a serialized AST.
@@ -80,6 +84,7 @@ struct ValidationInfo {
   StringRef miscVersion = {};
   version::Version compatibilityVersion = {};
   llvm::VersionTuple userModuleVersion;
+  StringRef sdkName = {};
   size_t bytes = 0;
   Status status = Status::Malformed;
 };

lib/Frontend/CompilerInvocation.cpp

@@ -774,6 +774,11 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     }
   }
 
+  // Get the SDK name.
+  if (Arg *A = Args.getLastArg(options::OPT_target_sdk_name)) {
+    Opts.SDKName = A->getValue();
+  }
+
   if (const Arg *A = Args.getLastArg(OPT_entry_point_function_name)) {
     Opts.entryPointFunctionName = A->getValue();
   }

lib/Frontend/Frontend.cpp

@@ -150,6 +150,7 @@ SerializationOptions CompilerInvocation::computeSerializationOptions(
   serializationOpts.ExtraClangOptions = getClangImporterOptions().ExtraArgs;
   serializationOpts.PublicDependentLibraries =
       getIRGenOptions().PublicLinkLibraries;
+  serializationOpts.SDKName = getLangOptions().SDKName;
 
   if (opts.EmitSymbolGraph) {
     if (!opts.SymbolGraphOutputDir.empty()) {

lib/Frontend/ModuleInterfaceBuilder.cpp

@@ -257,6 +257,8 @@ bool ModuleInterfaceBuilder::buildSwiftModuleInternal(
     if (!getRelativeDepPath(InPath, SDKPath))
       SerializationOpts.ModuleInterface = InPath;
 
+    SerializationOpts.SDKName = SubInstance.getASTContext().LangOpts.SDKName;
+
     SmallVector<FileDependency, 16> Deps;
     bool serializeHashes = FEOpts.SerializeModuleInterfaceDependencyHashes;
     if (collectDepsForSerialization(SubInstance, Deps, serializeHashes)) {

lib/Serialization/ModuleFile.cpp

@@ -149,6 +149,15 @@ Status ModuleFile::associateWithFileContext(FileUnit *file, SourceLoc diagLoc,
       return error(status);
   }
 
+  auto clientSDK = ctx.LangOpts.SDKName;
+  StringRef moduleSDK = Core->SDKName;
+  if (ctx.SearchPathOpts.EnableSameSDKCheck &&
+      !moduleSDK.empty() && !clientSDK.empty() &&
+      moduleSDK != clientSDK) {
+    status = Status::SDKMismatch;
+    return error(status);
+  }
+
   for (const auto &searchPath : Core->SearchPaths)
     ctx.addSearchPath(searchPath.Path, searchPath.IsFramework,
                       searchPath.IsSystem);