[wasm] Backoff implementation for F64Trunc using std::trunc.

src/assembler.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 889 matching lines @@
   static ExternalReference get_date_field_function(Isolate* isolate);
   static ExternalReference date_cache_stamp(Isolate* isolate);
 
   static ExternalReference get_make_code_young_function(Isolate* isolate);
   static ExternalReference get_mark_code_as_executed_function(Isolate* isolate);
 
   // Deoptimization support.
   static ExternalReference new_deoptimizer_function(Isolate* isolate);
   static ExternalReference compute_output_frames_function(Isolate* isolate);
 
+  static ExternalReference trunc64_wrapper_function(Isolate* isolate);
+
   // Log support.
   static ExternalReference log_enter_external_function(Isolate* isolate);
   static ExternalReference log_leave_external_function(Isolate* isolate);
 
   // Static data in the keyed lookup cache.
   static ExternalReference keyed_lookup_cache_keys(Isolate* isolate);
   static ExternalReference keyed_lookup_cache_field_offsets(Isolate* isolate);
 
   // Static variable Heap::roots_array_start()
   static ExternalReference roots_array_start(Isolate* isolate);
@@ skipping 362 matching lines @@
     std::vector<ConstantPoolEntry> shared_entries;
   };
 
   Label emitted_label_;  // Records pc_offset of emitted pool
   PerTypeEntryInfo info_[ConstantPoolEntry::NUMBER_OF_TYPES];
 };
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_ASSEMBLER_H_