Optimize AOT's switchable calls for the monomorphic case.

runtime/vm/stack_frame.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/stack_frame.h"
 
 #include "platform/memory_sanitizer.h"
 #include "vm/assembler.h"
 #include "vm/deopt_instructions.h"
 #include "vm/isolate.h"
@@ skipping 90 matching lines @@
   if (!code.IsNull()) {
     // Visit the code object.
     RawObject* raw_code = code.raw();
     visitor->VisitPointer(&raw_code);
 
     // Optimized frames have a stack map. We need to visit the frame based
     // on the stack map.
     Array maps;
     maps = Array::null();
     Stackmap map;
-    const uword entry = reinterpret_cast<uword>(code.instructions()->ptr()) +
-                        Instructions::HeaderSize();
-    map = code.GetStackmap(pc() - entry, &maps, &map);
+    const uword start = Instructions::PayloadStart(code.instructions());
+    map = code.GetStackmap(pc() - start, &maps, &map);
     if (!map.IsNull()) {
 #if !defined(TARGET_ARCH_DBC)
       RawObject** first = reinterpret_cast<RawObject**>(sp());
       RawObject** last = reinterpret_cast<RawObject**>(
           fp() + (kFirstLocalSlotFromFp * kWordSize));
 
       // A stack map is present in the code object, use the stack map to
       // visit frame slots which are marked as having objects.
       //
       // The layout of the frame is (lower addresses to the right):
@@ skipping 129 matching lines @@
 bool StackFrame::FindExceptionHandler(Thread* thread,
                                       uword* handler_pc,
                                       bool* needs_stacktrace,
                                       bool* has_catch_all) const {
   REUSABLE_CODE_HANDLESCOPE(thread);
   Code& code = reused_code_handle.Handle();
   code = LookupDartCode();
   if (code.IsNull()) {
     return false;  // Stub frames do not have exception handlers.
   }
-  uword pc_offset = pc() - code.EntryPoint();
+  uword pc_offset = pc() - code.PayloadStart();
 
   REUSABLE_EXCEPTION_HANDLERS_HANDLESCOPE(thread);
   ExceptionHandlers& handlers = reused_exception_handlers_handle.Handle();
   handlers = code.exception_handlers();
   if (handlers.num_entries() == 0) {
     return false;
   }
 
   // Find pc descriptor for the current pc.
   REUSABLE_PC_DESCRIPTORS_HANDLESCOPE(thread);
   PcDescriptors& descriptors = reused_pc_descriptors_handle.Handle();
   descriptors = code.pc_descriptors();
   PcDescriptors::Iterator iter(descriptors, RawPcDescriptors::kAnyKind);
   while (iter.MoveNext()) {
     const intptr_t current_try_index = iter.TryIndex();
     if ((iter.PcOffset() == pc_offset) && (current_try_index != -1)) {
       RawExceptionHandlers::HandlerInfo handler_info;
       handlers.GetHandlerInfo(current_try_index, &handler_info);
-      *handler_pc = code.EntryPoint() + handler_info.handler_pc_offset;
+      *handler_pc = code.PayloadStart() + handler_info.handler_pc_offset;
       *needs_stacktrace = handler_info.needs_stacktrace;
       *has_catch_all = handler_info.has_catch_all;
       return true;
     }
   }
   return false;
 }
 
 
 TokenPosition StackFrame::GetTokenPos() const {
   const Code& code = Code::Handle(LookupDartCode());
   if (code.IsNull()) {
     return TokenPosition::kNoSource;  // Stub frames do not have token_pos.
   }
-  uword pc_offset = pc() - code.EntryPoint();
+  uword pc_offset = pc() - code.PayloadStart();
   const PcDescriptors& descriptors =
       PcDescriptors::Handle(code.pc_descriptors());
   ASSERT(!descriptors.IsNull());
   PcDescriptors::Iterator iter(descriptors, RawPcDescriptors::kAnyKind);
   while (iter.MoveNext()) {
     if (iter.PcOffset() == pc_offset) {
       return TokenPosition(iter.TokenPos());
     }
   }
   return TokenPosition::kNoSource;
@@ skipping 253 matching lines @@
       return (index - num_materializations_);
 #endif
     }
   }
   UNREACHABLE();
   return 0;
 }
 
 
 }  // namespace dart