Make ASTFileSignature an array of 20 uint8_t instead of 5 uint32_t

Reviewers: aprantl, dexonsmith, Bigcheese

Subscribers: arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D81347
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 65d513c8..6965c4a 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2535,10 +2535,14 @@
     // PCH files don't have a signature field in the control block,
     // but LLVM detects skeleton CUs by looking for a non-zero DWO id.
     // We use the lower 64 bits for debug info.
-    uint64_t Signature =
-        Mod.getSignature()
-            ? (uint64_t)Mod.getSignature()[1] << 32 | Mod.getSignature()[0]
-            : ~1ULL;
+
+    uint64_t Signature = 0;
+    if (const auto &ModSig = Mod.getSignature()) {
+      for (unsigned I = 0; I != sizeof(Signature); ++I)
+        Signature |= (uint64_t)ModSig[I] << (I * 8);
+    } else {
+      Signature = ~1ULL;
+    }
     llvm::DIBuilder DIB(CGM.getModule());
     SmallString<0> PCM;
     if (!llvm::sys::path::is_absolute(Mod.getASTFile()))
diff --git a/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp b/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
index 284e802..0c7e5f4 100644
--- a/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
+++ b/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
@@ -173,8 +173,8 @@
     // Prepare CGDebugInfo to emit debug info for a clang module.
     auto *DI = Builder->getModuleDebugInfo();
     StringRef ModuleName = llvm::sys::path::filename(MainFileName);
-    DI->setPCHDescriptor({ModuleName, "", OutputFileName,
-                          ASTFileSignature{{{~0U, ~0U, ~0U, ~0U, ~1U}}}});
+    DI->setPCHDescriptor(
+        {ModuleName, "", OutputFileName, ASTFileSignature::createDISentinel()});
     DI->setModuleMap(MMap);
   }
 
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 8798706..673b65d 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -2791,10 +2791,10 @@
             ReadUntranslatedSourceLocation(Record[Idx++]);
         off_t StoredSize = (off_t)Record[Idx++];
         time_t StoredModTime = (time_t)Record[Idx++];
-        ASTFileSignature StoredSignature = {
-            {{(uint32_t)Record[Idx++], (uint32_t)Record[Idx++],
-              (uint32_t)Record[Idx++], (uint32_t)Record[Idx++],
-              (uint32_t)Record[Idx++]}}};
+        auto FirstSignatureByte = Record.begin() + Idx;
+        ASTFileSignature StoredSignature = ASTFileSignature::create(
+            FirstSignatureByte, FirstSignatureByte + ASTFileSignature::size);
+        Idx += ASTFileSignature::size;
 
         std::string ImportedName = ReadString(Record, Idx);
         std::string ImportedFile;
@@ -4734,7 +4734,7 @@
     switch ((UnhashedControlBlockRecordTypes)MaybeRecordType.get()) {
     case SIGNATURE:
       if (F)
-        std::copy(Record.begin(), Record.end(), F->Signature.data());
+        F->Signature = ASTFileSignature::create(Record.begin(), Record.end());
       break;
     case DIAGNOSTIC_OPTIONS: {
       bool Complain = (ClientLoadCapabilities & ARR_OutOfDate) == 0;
@@ -5023,8 +5023,8 @@
       return ASTFileSignature();
     }
     if (SIGNATURE == MaybeRecord.get())
-      return {{{(uint32_t)Record[0], (uint32_t)Record[1], (uint32_t)Record[2],
-                (uint32_t)Record[3], (uint32_t)Record[4]}}};
+      return ASTFileSignature::create(Record.begin(),
+                                      Record.begin() + ASTFileSignature::size);
   }
 }
 
@@ -5322,7 +5322,9 @@
       unsigned Idx = 0, N = Record.size();
       while (Idx < N) {
         // Read information about the AST file.
-        Idx += 1+1+1+1+5; // Kind, ImportLoc, Size, ModTime, Signature
+        Idx +=
+            1 + 1 + 1 + 1 +
+            ASTFileSignature::size; // Kind, ImportLoc, Size, ModTime, Signature
         std::string ModuleName = ReadString(Record, Idx);
         std::string Filename = ReadString(Record, Idx);
         ResolveImportedPath(Filename, ModuleDir);
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index e1fbe56..5120872 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1032,16 +1032,7 @@
   Hasher.update(ArrayRef<uint8_t>(Bytes.bytes_begin(), Bytes.size()));
   auto Hash = Hasher.result();
 
-  // Convert to an array [5*i32].
-  ASTFileSignature Signature;
-  auto LShift = [&](unsigned char Val, unsigned Shift) {
-    return (uint32_t)Val << Shift;
-  };
-  for (int I = 0; I != 5; ++I)
-    Signature[I] = LShift(Hash[I * 4 + 0], 24) | LShift(Hash[I * 4 + 1], 16) |
-                   LShift(Hash[I * 4 + 2], 8) | LShift(Hash[I * 4 + 3], 0);
-
-  return Signature;
+  return ASTFileSignature::create(Hash);
 }
 
 ASTFileSignature ASTWriter::writeUnhashedControlBlock(Preprocessor &PP,
diff --git a/clang/lib/Serialization/GlobalModuleIndex.cpp b/clang/lib/Serialization/GlobalModuleIndex.cpp
index 462d29c..958cca7 100644
--- a/clang/lib/Serialization/GlobalModuleIndex.cpp
+++ b/clang/lib/Serialization/GlobalModuleIndex.cpp
@@ -643,10 +643,10 @@
 
         // Skip the stored signature.
         // FIXME: we could read the signature out of the import and validate it.
-        ASTFileSignature StoredSignature = {
-            {{(uint32_t)Record[Idx++], (uint32_t)Record[Idx++],
-              (uint32_t)Record[Idx++], (uint32_t)Record[Idx++],
-              (uint32_t)Record[Idx++]}}};
+        auto FirstSignatureByte = Record.begin() + Idx;
+        ASTFileSignature StoredSignature = ASTFileSignature::create(
+            FirstSignatureByte, FirstSignatureByte + ASTFileSignature::size);
+        Idx += ASTFileSignature::size;
 
         // Skip the module name (currently this is only used for prebuilt
         // modules while here we are only dealing with cached).
@@ -704,9 +704,8 @@
 
     // Get Signature.
     if (State == DiagnosticOptionsBlock && Code == SIGNATURE)
-      getModuleFileInfo(File).Signature = {
-          {{(uint32_t)Record[0], (uint32_t)Record[1], (uint32_t)Record[2],
-            (uint32_t)Record[3], (uint32_t)Record[4]}}};
+      getModuleFileInfo(File).Signature = ASTFileSignature::create(
+          Record.begin(), Record.begin() + ASTFileSignature::size);
 
     // We don't care about this record.
   }