[string] Widen StringIndexOf fast path

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index d1bbd88c1971383ca19a6d6f49e966b62022bd85..e27aed5f34dd2121475dd9dd21d2e5699f2130d7 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -63,6 +63,7 @@
 #include "src/runtime/runtime.h"
 #include "src/simulator.h"  // For flushing instruction cache.
 #include "src/snapshot/serializer-common.h"
+#include "src/string-search.h"
 #include "src/wasm/wasm-external-refs.h"
 
 // Include native regexp-macro-assembler.
@@ -1562,12 +1563,28 @@ ExternalReference ExternalReference::libc_memset_function(Isolate* isolate) {
   return ExternalReference(Redirect(isolate, FUNCTION_ADDR(libc_memset)));
 }
 
+template <typename SubjectChar, typename PatternChar>
+ExternalReference ExternalReference::search_string_raw(Isolate* isolate) {
+  auto f = SearchStringRaw<SubjectChar, PatternChar>;
+  return ExternalReference(Redirect(isolate, FUNCTION_ADDR(f)));
+}
+
 ExternalReference ExternalReference::try_internalize_string_function(
     Isolate* isolate) {
   return ExternalReference(Redirect(
       isolate, FUNCTION_ADDR(StringTable::LookupStringIfExists_NoAllocate)));
 }
 
+// Explicit instantiations for all combinations of 1- and 2-byte strings.
+template ExternalReference
+ExternalReference::search_string_raw<const uint8_t, const uint8_t>(Isolate*);
+template ExternalReference
+ExternalReference::search_string_raw<const uint8_t, const uc16>(Isolate*);
+template ExternalReference
+ExternalReference::search_string_raw<const uc16, const uint8_t>(Isolate*);
+template ExternalReference
+ExternalReference::search_string_raw<const uc16, const uc16>(Isolate*);
+
 ExternalReference ExternalReference::page_flags(Page* page) {
   return ExternalReference(reinterpret_cast<Address>(page) +
                            MemoryChunk::kFlagsOffset);