ModuleInterface: refactor out a utility to extract compiler flags from a module interface file. NFC

include/swift/Frontend/ModuleInterfaceSupport.h

@@ -57,7 +57,6 @@ std::string getSwiftInterfaceCompilerVersionForCurrentCompiler(ASTContext &ctx);
 
 llvm::Regex getSwiftInterfaceFormatVersionRegex();
 llvm::Regex getSwiftInterfaceCompilerVersionRegex();
-llvm::Regex getSwiftInterfaceModuleFlagsRegex();
 
 /// Emit a stable module interface for \p M, which can be used by a client
 /// source file to import this module, subject to options given by \p Opts.

include/swift/Serialization/SerializedModuleLoader.h

@@ -461,7 +461,9 @@ class SerializedASTFile final : public LoadedFile {
   }
 };
 
-
+/// Extract compiler arguments from an interface file buffer.
+bool extractCompilerFlagsFromInterface(StringRef buffer, llvm::StringSaver &ArgSaver,
+                                       SmallVectorImpl<const char *> &SubArgs);
 } // end namespace swift
 
 #endif

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -1191,24 +1191,21 @@ bool InterfaceSubContextDelegateImpl::extractSwiftInterfaceVersionAndArgs(
   auto SB = FileOrError.get()->getBuffer();
   auto VersRe = getSwiftInterfaceFormatVersionRegex();
   auto CompRe = getSwiftInterfaceCompilerVersionRegex();
-  auto FlagRe = getSwiftInterfaceModuleFlagsRegex();
-  SmallVector<StringRef, 1> VersMatches, FlagMatches, CompMatches;
+  SmallVector<StringRef, 1> VersMatches, CompMatches;
 
   if (!VersRe.match(SB, &VersMatches)) {
     diagnose(interfacePath, diagnosticLoc,
              diag::error_extracting_version_from_module_interface);
     return true;
   }
-  if (!FlagRe.match(SB, &FlagMatches)) {
+  if (extractCompilerFlagsFromInterface(SB, ArgSaver, SubArgs)) {
     diagnose(interfacePath, diagnosticLoc,
              diag::error_extracting_version_from_module_interface);
     return true;
   }
   assert(VersMatches.size() == 2);
-  assert(FlagMatches.size() == 2);
   // FIXME We should diagnose this at a location that makes sense:
   auto Vers = swift::version::Version(VersMatches[1], SourceLoc(), &Diags);
-  llvm::cl::TokenizeGNUCommandLine(FlagMatches[1], ArgSaver, SubArgs);
 
   if (CompRe.match(SB, &CompMatches)) {
     assert(CompMatches.size() == 2);

lib/Frontend/ModuleInterfaceSupport.cpp

@@ -69,11 +69,6 @@ llvm::Regex swift::getSwiftInterfaceFormatVersionRegex() {
                      ": ([0-9\\.]+)$", llvm::Regex::Newline);
 }
 
-llvm::Regex swift::getSwiftInterfaceModuleFlagsRegex() {
-  return llvm::Regex("^// " SWIFT_MODULE_FLAGS_KEY ":(.*)$",
-                     llvm::Regex::Newline);
-}
-
 llvm::Regex swift::getSwiftInterfaceCompilerVersionRegex() {
   return llvm::Regex("^// " SWIFT_COMPILER_VERSION_KEY
                      ": (.+)$", llvm::Regex::Newline);

lib/Serialization/SerializedModuleLoader.cpp

@@ -30,6 +30,7 @@
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/CommandLine.h"
 #include <system_error>
 
 using namespace swift;
@@ -947,6 +948,18 @@ void swift::serialization::diagnoseSerializedASTLoadFailure(
   }
 }
 
+bool swift::extractCompilerFlagsFromInterface(StringRef buffer,
+                                              llvm::StringSaver &ArgSaver,
+                                              SmallVectorImpl<const char *> &SubArgs) {
+  SmallVector<StringRef, 1> FlagMatches;
+  auto FlagRe = llvm::Regex("^// swift-module-flags:(.*)$", llvm::Regex::Newline);
+  if (!FlagRe.match(buffer, &FlagMatches))
+    return true;
+  assert(FlagMatches.size() == 2);
+  llvm::cl::TokenizeGNUCommandLine(FlagMatches[1], ArgSaver, SubArgs);
+  return false;
+}
+
 bool SerializedModuleLoaderBase::canImportModule(
     ImportPath::Element mID, llvm::VersionTuple version, bool underlyingVersion) {
   // Look on disk.