[ModuleInterface] Version string (semi)finalization, format version checking.

include/swift/AST/DiagnosticsFrontend.def

@@ -265,6 +265,9 @@ WARNING(parseable_interface_scoped_import_unsupported,none,
         ())
 ERROR(error_extracting_version_from_parseable_interface,none,
       "error extracting version from parseable module interface", ())
+ERROR(unsupported_version_of_parseable_interface,none,
+      "unsupported version of parseable module interface '%0': '%1'",
+      (StringRef, llvm::VersionTuple))
 ERROR(error_extracting_flags_from_parseable_interface,none,
       "error extracting flags from parseable module interface", ())
 ERROR(missing_dependency_of_parseable_module_interface,none,

include/swift/Frontend/ParseableInterfaceSupport.h

@@ -29,7 +29,7 @@ struct ParseableInterfaceOptions {
   std::string ParseableInterfaceFlags;
 };
 
-llvm::Regex getSwiftInterfaceToolsVersionRegex();
+llvm::Regex getSwiftInterfaceFormatVersionRegex();
 llvm::Regex getSwiftInterfaceModuleFlagsRegex();
 
 /// Emit a stable, parseable interface for \p M, which can be used by a client

lib/Frontend/ParseableInterfaceSupport.cpp

@@ -39,9 +39,12 @@
 using namespace swift;
 using FileDependency = SerializationOptions::FileDependency;
 
+#define SWIFT_INTERFACE_FORMAT_VERSION_KEY "swift-interface-format-version"
 #define SWIFT_TOOLS_VERSION_KEY "swift-tools-version"
 #define SWIFT_MODULE_FLAGS_KEY "swift-module-flags"
 
+static swift::version::Version InterfaceFormatVersion({1, 0});
+
 static bool
 extractSwiftInterfaceVersionAndArgs(DiagnosticEngine &Diags,
                                     clang::vfs::FileSystem &FS,
@@ -56,7 +59,7 @@ extractSwiftInterfaceVersionAndArgs(DiagnosticEngine &Diags,
     return true;
   }
   auto SB = FileOrError.get()->getBuffer();
-  auto VersRe = getSwiftInterfaceToolsVersionRegex();
+  auto VersRe = getSwiftInterfaceFormatVersionRegex();
   auto FlagRe = getSwiftInterfaceModuleFlagsRegex();
   SmallVector<StringRef, 1> VersMatches, FlagMatches;
   if (!VersRe.match(SB, &VersMatches)) {
@@ -286,6 +289,17 @@ static bool buildSwiftModuleFromSwiftInterface(
       return;
     }
 
+    // For now: we support anything with the same "major version" and assume
+    // minor versions might be interesting for debugging, or special-casing a
+    // compatible field variant.
+    if (Vers.asMajorVersion() != InterfaceFormatVersion.asMajorVersion()) {
+      Diags.diagnose(SourceLoc(),
+                     diag::unsupported_version_of_parseable_interface,
+                     InPath, Vers);
+      SubError = true;
+      return;
+    }
+
     if (SubInvocation.parseArgs(SubArgs, Diags)) {
       SubError = true;
       return;
@@ -415,21 +429,26 @@ static void diagnoseScopedImports(DiagnosticEngine &diags,
   }
 }
 
-/// Prints to \p out a comment containing a tool-versions identifier as well
-/// as any relevant command-line flags in \p Opts used to construct \p M.
+/// Prints to \p out a comment containing a format version number, tool version
+/// string as well as any relevant command-line flags in \p Opts used to
+/// construct \p M.
 static void printToolVersionAndFlagsComment(raw_ostream &out,
                                             ParseableInterfaceOptions const &Opts,
                                             ModuleDecl *M) {
   auto &Ctx = M->getASTContext();
+  auto ToolsVersion = swift::version::getSwiftFullVersion(
+      Ctx.LangOpts.EffectiveLanguageVersion);
+  out << "// " SWIFT_INTERFACE_FORMAT_VERSION_KEY ": "
+      << InterfaceFormatVersion << "\n";
   out << "// " SWIFT_TOOLS_VERSION_KEY ": "
-      << Ctx.LangOpts.EffectiveLanguageVersion << "\n";
+      << ToolsVersion << "\n";
   out << "// " SWIFT_MODULE_FLAGS_KEY ": "
       << Opts.ParseableInterfaceFlags << "\n";
 }
 
-llvm::Regex swift::getSwiftInterfaceToolsVersionRegex() {
-  return llvm::Regex("^// " SWIFT_TOOLS_VERSION_KEY ": ([0-9\\.]+)$",
-                     llvm::Regex::Newline);
+llvm::Regex swift::getSwiftInterfaceFormatVersionRegex() {
+  return llvm::Regex("^// " SWIFT_INTERFACE_FORMAT_VERSION_KEY
+                     ": ([0-9\\.]+)$", llvm::Regex::Newline);
 }
 
 llvm::Regex swift::getSwiftInterfaceModuleFlagsRegex() {

test/ParseableInterface/ModuleCache/module-cache-bad-version.swift

@@ -0,0 +1,30 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/modulecache)
+//
+// Test will build a module TestModule that depends LeafModule (built from leaf.swift).
+//
+// RUN: echo 'public func LeafFunc() -> Int { return 10; }' >%t/leaf.swift
+//
+// RUN: %target-swift-frontend -I %t -emit-parseable-module-interface-path %t/LeafModule.swiftinterface -module-name LeafModule %t/leaf.swift -emit-module -o /dev/null
+// RUN: test -f %t/LeafModule.swiftinterface
+// RUN: %FileCheck %s -check-prefix=CHECK-LEAFINTERFACE <%t/LeafModule.swiftinterface
+// CHECK-LEAFINTERFACE: {{swift-interface-format-version: [0-9\\.]+}}
+// CHECK-LEAFINTERFACE: LeafFunc
+//
+// Break LeafModule's version number
+// RUN: sed -i.prev -e 's/swift-interface-format-version:.*/swift-interface-format-version: 9999.999/' %t/LeafModule.swiftinterface
+//
+// Try to build TestModule into a .swiftmodule explicitly using LeafModule via LeafModule.swiftinterface, but fail because version mismatch in LeafModule.swiftinterface.
+//
+// RUN: not %target-swift-frontend -I %t -module-cache-path %t/modulecache -enable-parseable-module-interface -emit-module  -o %t/TestModule.swiftmodule -module-name TestModule %s >%t/err.txt 2>&1
+// RUN: test ! -f %t/TestModule.swiftmodule
+// RUN: test ! -f %t/modulecache/LeafModule-*.swiftmodule
+// RUN: %FileCheck %s -check-prefix=CHECK-ERR <%t/err.txt
+// CHECK-ERR: {{error: unsupported version of parseable module interface '.*/LeafModule.swiftinterface': '9999.999'}}
+// CHECK-ERR: error: no such module 'LeafModule
+
+import LeafModule
+
+public func TestFunc() {
+    print(LeafFunc())
+}

test/ParseableInterface/ModuleCache/module-cache-diagnostics.swift

@@ -54,8 +54,8 @@
 // RUN: not %target-swift-frontend -I %t -module-cache-path %t/modulecache -enable-parseable-module-interface -emit-module -o %t/TestModule.swiftmodule -module-name TestModule %s >%t/err.txt 2>&1
 // RUN: %S/Inputs/check-is-old.py %t/modulecache/OtherModule-*.swiftmodule %t/modulecache/LeafModule-*.swiftmodule
 // RUN: %FileCheck %s -check-prefix=CHECK-ERROR <%t/err.txt
-// CHECK-ERROR: LeafModule.swiftinterface:5:8: error: no such module 'NotAModule'
-// CHECK-ERROR: OtherModule.swiftinterface:3:8: error: no such module 'LeafModule'
+// CHECK-ERROR: LeafModule.swiftinterface:6:8: error: no such module 'NotAModule'
+// CHECK-ERROR: OtherModule.swiftinterface:4:8: error: no such module 'LeafModule'
 //
 //
 // Next test: same as above, but with a .dia file