add fingerprint excluding to basic source file info

Author: David Ungar

include/swift/AST/RawComment.h

@@ -104,6 +104,10 @@ class BasicSourceFileInfo {
 
   StringRef FilePath;
   Fingerprint InterfaceHashIncludingTypeMembers = Fingerprint::ZERO();
+  /// Does *not* include the type-body hashes of the top level types.
+  /// Just the `SourceFile` hashes.
+  /// Used for incremental imports.
+  Fingerprint InterfaceHashExcludingTypeMembers = Fingerprint::ZERO();
   llvm::sys::TimePoint<> LastModified = {};
   uint64_t FileSize = 0;
 
@@ -113,14 +117,16 @@ class BasicSourceFileInfo {
 public:
   BasicSourceFileInfo(StringRef FilePath,
                       Fingerprint InterfaceHashIncludingTypeMembers,
+                      Fingerprint InterfaceHashExcludingTypeMembers,
                       llvm::sys::TimePoint<> LastModified, uint64_t FileSize)
       : FilePath(FilePath),
         InterfaceHashIncludingTypeMembers(InterfaceHashIncludingTypeMembers),
+        InterfaceHashExcludingTypeMembers(InterfaceHashExcludingTypeMembers),
         LastModified(LastModified), FileSize(FileSize) {}
 
-  ///  Construct with a 'SourceFile'. 'getInterfaceHashIncludingTypeMembers()',
-  ///  'getLastModified()' and 'getFileSize()' are laizily pupulated when
-  ///  accessed.
+  ///  Construct with a `SourceFile`. `getInterfaceHashIncludingTypeMembers()`,
+  ///  `getInterfaceHashExcludingTypeMembers()`, `getLastModified()` and `getFileSize()` are laizily
+  ///  populated when accessed.
   BasicSourceFileInfo(const SourceFile *SF);
 
   bool isFromSourceFile() const;
@@ -132,6 +138,11 @@ class BasicSourceFileInfo {
     return InterfaceHashIncludingTypeMembers;
   }
 
+  Fingerprint getInterfaceHashExcludingTypeMembers() const {
+    const_cast<BasicSourceFileInfo *>(this)->populateWithSourceFileIfNeeded();
+    return InterfaceHashExcludingTypeMembers;
+  }
+
   llvm::sys::TimePoint<> getLastModified() const {
     const_cast<BasicSourceFileInfo *>(this)->populateWithSourceFileIfNeeded();
     return LastModified;

lib/AST/Module.cpp

@@ -1550,7 +1550,9 @@ Fingerprint ModuleDecl::getFingerprint() const {
   StableHasher hasher = StableHasher::defaultHasher();
   SmallVector<Fingerprint, 16> FPs;
   collectBasicSourceFileInfo([&](const BasicSourceFileInfo &bsfi) {
-    FPs.emplace_back(bsfi.getInterfaceHashIncludingTypeMembers());
+    // For incremental imports, the hash must be insensitive to type-body
+    // changes, so use the one without type members.
+    FPs.emplace_back(bsfi.getInterfaceHashExcludingTypeMembers());
   });
 
   // Sort the fingerprints lexicographically so we have a stable hash despite

lib/AST/RawComment.cpp

@@ -278,9 +278,11 @@ void BasicSourceFileInfo::populateWithSourceFileIfNeeded() {
 
   if (SF->hasInterfaceHash()) {
     InterfaceHashIncludingTypeMembers = SF->getInterfaceHashIncludingTypeMembers();
+    InterfaceHashExcludingTypeMembers = SF->getInterfaceHash();
   } else {
     // FIXME: Parse the file with EnableInterfaceHash option.
     InterfaceHashIncludingTypeMembers = Fingerprint::ZERO();
+    InterfaceHashExcludingTypeMembers = Fingerprint::ZERO();
   }
 
   return;

lib/Serialization/ModuleFile.cpp

@@ -978,10 +978,17 @@ void ModuleFile::collectBasicSourceFileInfo(
   while (Cursor < End) {
     // FilePath (byte offset in 'SourceLocsTextData').
     auto fileID = endian::readNext<uint32_t, little, unaligned>(Cursor);
-    // InterfaceHash (fixed length string).
-    auto fpStr = StringRef{reinterpret_cast<const char *>(Cursor),
+
+    // InterfaceHashIncludingTypeMembers (fixed length string).
+    auto fpStrIncludingTypeMembers = StringRef{reinterpret_cast<const char *>(Cursor),
+                           Fingerprint::DIGEST_LENGTH};
+    Cursor += Fingerprint::DIGEST_LENGTH;
+
+    // InterfaceHashExcludingTypeMembers (fixed length string).
+    auto fpStrExcludingTypeMembers = StringRef{reinterpret_cast<const char *>(Cursor),
                            Fingerprint::DIGEST_LENGTH};
     Cursor += Fingerprint::DIGEST_LENGTH;
+
     // LastModified (nanoseconds since epoch).
     auto timestamp = endian::readNext<uint64_t, little, unaligned>(Cursor);
     // FileSize (num of bytes).
@@ -992,13 +999,25 @@ void ModuleFile::collectBasicSourceFileInfo(
     size_t terminatorOffset = filePath.find('\0');
     filePath = filePath.slice(0, terminatorOffset);
 
-    auto fingerprint = Fingerprint::fromString(fpStr);
-    if (!fingerprint) {
-      llvm::errs() << "Unconvertable fingerprint '" << fpStr << "'\n";
+    auto fingerprintIncludingTypeMembers =
+      Fingerprint::fromString(fpStrIncludingTypeMembers);
+    if (!fingerprintIncludingTypeMembers) {
+      llvm::errs() << "Unconvertible fingerprint including type members'"
+                   << fpStrIncludingTypeMembers << "'\n";
       abort();
     }
-
-    callback(BasicSourceFileInfo(filePath, fingerprint.getValue(), llvm::sys::TimePoint<>(std::chrono::nanoseconds(timestamp)), fileSize));
+    auto fingerprintExcludingTypeMembers =
+      Fingerprint::fromString(fpStrExcludingTypeMembers);
+    if (!fingerprintExcludingTypeMembers) {
+      llvm::errs() << "Unconvertible fingerprint excluding type members'"
+                   << fpStrExcludingTypeMembers << "'\n";
+      abort();
+    }
+    callback(BasicSourceFileInfo(filePath,
+                                 fingerprintIncludingTypeMembers.getValue(),
+                                 fingerprintExcludingTypeMembers.getValue(),
+                                 llvm::sys::TimePoint<>(std::chrono::nanoseconds(timestamp)),
+                                 fileSize));
   }
 }
 

lib/Serialization/SerializeDoc.cpp

@@ -805,7 +805,12 @@ static void emitFileListRecord(llvm::BitstreamWriter &Out,
         return;
 
       auto fileID = FWriter.getTextOffset(absolutePath);
-      auto fingerprintStr = info.getInterfaceHashIncludingTypeMembers().getRawValue();
+
+      auto fingerprintStrIncludingTypeMembers =
+        info.getInterfaceHashIncludingTypeMembers().getRawValue();
+      auto fingerprintStrExcludingTypeMembers =
+        info.getInterfaceHashExcludingTypeMembers().getRawValue();
+
       auto timestamp = std::chrono::duration_cast<std::chrono::nanoseconds>(
                            info.getLastModified().time_since_epoch())
                            .count();
@@ -814,9 +819,15 @@ static void emitFileListRecord(llvm::BitstreamWriter &Out,
       endian::Writer writer(out, little);
       // FilePath.
       writer.write<uint32_t>(fileID);
-      // InterfaceHash (fixed length string).
-      assert(fingerprintStr.size() == Fingerprint::DIGEST_LENGTH);
-      out << fingerprintStr;
+
+      // InterfaceHashIncludingTypeMembers (fixed length string).
+      assert(fingerprintStrIncludingTypeMembers.size() == Fingerprint::DIGEST_LENGTH);
+      out << fingerprintStrIncludingTypeMembers;
+
+      // InterfaceHashExcludingTypeMembers (fixed length string).
+      assert(fingerprintStrExcludingTypeMembers.size() == Fingerprint::DIGEST_LENGTH);
+      out << fingerprintStrExcludingTypeMembers;
+
       // LastModified (nanoseconds since epoch).
       writer.write<uint64_t>(timestamp);
       // FileSize (num of bytes).