[wasm] Complete separation of compilation and instantiation

src/signature.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_SIGNATURE_H_
 #define V8_SIGNATURE_H_
 
 #include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 // Describes the inputs and outputs of a function or call.
 template <typename T>
 class Signature : public ZoneObject {
  public:
-  Signature(size_t return_count, size_t parameter_count, T* reps)
+  Signature(size_t return_count, size_t parameter_count, const T* reps)
       : return_count_(return_count),
         parameter_count_(parameter_count),
         reps_(reps) {}
 
   size_t return_count() const { return return_count_; }
   size_t parameter_count() const { return parameter_count_; }
 
   T GetParam(size_t index) const {
     DCHECK(index < parameter_count_);
     return reps_[return_count_ + index];
   }
 
   T GetReturn(size_t index = 0) const {
     DCHECK(index < return_count_);
     return reps_[index];
   }
 
+  const T* raw_data() const { return reps_; }
+
   // For incrementally building signatures.
   class Builder {
    public:
     Builder(Zone* zone, size_t return_count, size_t parameter_count)
         : return_count_(return_count),
           parameter_count_(parameter_count),
           zone_(zone),
           rcursor_(0),
           pcursor_(0),
           buffer_(zone->NewArray<T>(
@@ skipping 19 matching lines @@
    private:
     Zone* zone_;
     size_t rcursor_;
     size_t pcursor_;
     T* buffer_;
   };
 
  protected:
   size_t return_count_;
   size_t parameter_count_;
-  T* reps_;
+  const T* reps_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_SIGNATURE_H_