Multiple stubs can point to the same calling convention.

src/isolate.cc

 // Copyright 2012 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.
 
 #include <stdlib.h>
 
 #include "src/v8.h"
 
 #include "src/ast.h"
 #include "src/base/platform/platform.h"
@@ skipping 1902 matching lines @@
 
   // SetUp the object heap.
   DCHECK(!heap_.HasBeenSetUp());
   if (!heap_.SetUp()) {
     V8::FatalProcessOutOfMemory("heap setup");
     return false;
   }
 
   deoptimizer_data_ = new DeoptimizerData(memory_allocator_);
 
+  CallDescriptors::InitializeForIsolate(this);
+
   const bool create_heap_objects = (des == NULL);
   if (create_heap_objects && !heap_.CreateHeapObjects()) {
     V8::FatalProcessOutOfMemory("heap object creation");
     return false;
   }
 
   if (create_heap_objects) {
     // Terminate the cache array with the sentinel so we can iterate.
     PushToPartialSnapshotCache(heap_.undefined_value());
   }
@@ skipping 90 matching lines @@
     // Now that the heap is consistent, it's OK to generate the code for the
     // deopt entry table that might have been referred to by optimized code in
     // the snapshot.
     HandleScope scope(this);
     Deoptimizer::EnsureCodeForDeoptimizationEntry(
         this,
         Deoptimizer::LAZY,
         kDeoptTableSerializeEntryCount - 1);
   }
 
-  CallDescriptors::InitializeForIsolate(this);
-
   if (!serializer_enabled()) {
     // Ensure that all stubs which need to be generated ahead of time, but
     // cannot be serialized into the snapshot have been generated.
     HandleScope scope(this);
     CodeStub::GenerateFPStubs(this);
     StoreBufferOverflowStub::GenerateFixedRegStubsAheadOfTime(this);
     StubFailureTrampolineStub::GenerateAheadOfTime(this);
     // Ensure interface descriptors are initialized even when stubs have been
     // deserialized out of the snapshot without using the graph builder.
     FastCloneShallowArrayStub::InstallDescriptors(this);
@@ skipping 372 matching lines @@
   if (prev_ && prev_->Intercept(flag)) return true;
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 } }  // namespace v8::internal