[rebranch] Do not serialize unstable hashes

llvm/llvm-project#96282 changed
`get_execution_seed` to be non-deterministic. Use stable hashes instead.

Author: bnbarham

include/swift/Localization/LocalizationFormat.h

@@ -69,7 +69,7 @@ class LocalizationWriterInfo {
   using hash_value_type = uint32_t;
   using offset_type = uint32_t;
 
-  hash_value_type ComputeHash(key_type_ref key) { return llvm::hash_code(key); }
+  hash_value_type ComputeHash(key_type_ref key) { return key; }
 
   std::pair<offset_type, offset_type> EmitKeyDataLength(llvm::raw_ostream &out,
                                                         key_type_ref key,
@@ -113,7 +113,7 @@ class LocalizationReaderInfo {
   }
 
   hash_value_type ComputeHash(internal_key_type key) {
-    return llvm::hash_code(key);
+    return key;
   }
 
   static std::pair<offset_type, offset_type>

lib/ClangImporter/SwiftLookupTable.cpp

@@ -1142,7 +1142,7 @@ namespace {
     }
 
     hash_value_type ComputeHash(key_type_ref key) {
-      return llvm::DenseMapInfo<SerializedSwiftName>::getHashValue(key);
+      return static_cast<unsigned>(key.Kind) + llvm::djbHash(key.Name);
     }
 
     std::pair<unsigned, unsigned> EmitKeyDataLength(raw_ostream &out,
@@ -1421,7 +1421,7 @@ namespace {
     }
 
     hash_value_type ComputeHash(internal_key_type key) {
-      return llvm::DenseMapInfo<SerializedSwiftName>::getHashValue(key);
+      return static_cast<unsigned>(key.Kind) + llvm::djbHash(key.Name);
     }
 
     static bool EqualKey(internal_key_type lhs, internal_key_type rhs) {

lib/ClangImporter/SwiftLookupTable.h

@@ -283,7 +283,7 @@ const uint16_t SWIFT_LOOKUP_TABLE_VERSION_MAJOR = 1;
 /// Lookup table minor version number.
 ///
 /// When the format changes IN ANY WAY, this number should be incremented.
-const uint16_t SWIFT_LOOKUP_TABLE_VERSION_MINOR = 19; // 64-bit clang serialization IDs
+const uint16_t SWIFT_LOOKUP_TABLE_VERSION_MINOR = 20; // hash functions
 
 
 /// A lookup table that maps Swift names to the set of Clang

lib/Serialization/ModuleFileCoreTableInfo.h

@@ -318,7 +318,7 @@ class ModuleFileSharedCore::DeclMembersTableInfo {
   }
 
   hash_value_type ComputeHash(internal_key_type key) {
-    return llvm::hash_value(key);
+    return key;
   }
 
   static bool EqualKey(internal_key_type lhs, internal_key_type rhs) {
@@ -557,7 +557,7 @@ class ModuleFileSharedCore::DeclFingerprintsTableInfo {
   internal_key_type GetInternalKey(external_key_type ID) { return ID; }
 
   hash_value_type ComputeHash(internal_key_type key) {
-    return llvm::hash_value(key);
+    return key;
   }
 
   static bool EqualKey(internal_key_type lhs, internal_key_type rhs) {

lib/Serialization/ModuleFormat.h

@@ -58,7 +58,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 881; // Changes to LifetimeDependence
+const uint16_t SWIFTMODULE_VERSION_MINOR = 882; // hash functions
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///

lib/Serialization/Serialization.cpp

@@ -414,7 +414,7 @@ namespace {
     using offset_type = unsigned;
 
     hash_value_type ComputeHash(key_type_ref key) {
-      return llvm::hash_value(static_cast<uint32_t>(key));
+      return static_cast<uint32_t>(key);
     }
 
     std::pair<unsigned, unsigned> EmitKeyDataLength(raw_ostream &out,
@@ -459,7 +459,7 @@ namespace {
     using offset_type = unsigned;
 
     hash_value_type ComputeHash(key_type_ref key) {
-      return llvm::hash_value(static_cast<uint32_t>(key));
+      return static_cast<uint32_t>(key);
     }
 
     std::pair<unsigned, unsigned>