First step in reducing the size of PC descriptors.

runtime/vm/flow_graph_compiler_x64.cc

 // Copyright (c) 2013, 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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 982 matching lines @@
       __ addq(new_pc, Immediate(offset));
     }
 
     // Load callee's pool pointer.
     __ movq(new_pp, Address(new_pc, -object_pool_pc_dist - offset));
 
     // Load function object using the callee's pool pointer.
     __ LoadObject(function_reg, function, new_pp);
 
     // Patch point is after the eventually inlined function object.
-    AddCurrentDescriptor(PcDescriptors::kEntryPatch,
-                         Isolate::kNoDeoptId,
-                         0);  // No token position.
+    entry_patch_pc_offset_ = assembler()->CodeSize();
+
     if (is_optimizing()) {
       // Reoptimization of an optimized function is triggered by counting in
       // IC stubs, but not at the entry of the function.
       __ CompareImmediate(
           FieldAddress(function_reg, Function::usage_counter_offset()),
           Immediate(FLAG_reoptimization_counter_threshold),
           new_pp);
     } else {
       __ incq(FieldAddress(function_reg, Function::usage_counter_offset()));
       __ CompareImmediate(
@@ skipping 19 matching lines @@
         __ CodeSize();
     const intptr_t offset =
         Assembler::kEntryPointToPcMarkerOffset - __ CodeSize();
     __ popq(new_pc);
     if (offset != 0) {
       __ addq(new_pc, Immediate(offset));
     }
 
     // Load callee's pool pointer.
     __ movq(new_pp, Address(new_pc, -object_pool_pc_dist - offset));
-    AddCurrentDescriptor(PcDescriptors::kEntryPatch,
-                         Isolate::kNoDeoptId,
-                         0);  // No token position.
+
+    entry_patch_pc_offset_ = assembler()->CodeSize();
   }
   __ Comment("Enter frame");
   if (flow_graph().IsCompiledForOsr()) {
     intptr_t extra_slots = StackSize()
         - flow_graph().num_stack_locals()
         - flow_graph().num_copied_params();
     ASSERT(extra_slots >= 0);
     __ EnterOsrFrame(extra_slots * kWordSize, new_pp, new_pc);
   } else {
     ASSERT(StackSize() >= 0);
@@ skipping 77 matching lines @@
     }
   }
 
   ASSERT(!block_order().is_empty());
   VisitBlocks();
 
   __ int3();
   GenerateDeferredCode();
   // Emit function patching code. This will be swapped with the first 13 bytes
   // at entry point.
-  AddCurrentDescriptor(PcDescriptors::kPatchCode,
-                       Isolate::kNoDeoptId,
-                       0);  // No token position.
+  patch_code_pc_offset_ = assembler()->CodeSize();
   // This is patched up to a point in FrameEntry where the PP for the
   // current function is in R13 instead of PP.
   __ JmpPatchable(&StubCode::FixCallersTargetLabel(), R13);
 
-  AddCurrentDescriptor(PcDescriptors::kLazyDeoptJump,
-                       Isolate::kNoDeoptId,
-                       0);  // No token position.
-  __ Jmp(&StubCode::DeoptimizeLazyLabel(), PP);
+  if (is_optimizing()) {
+    lazy_deopt_pc_offset_ = assembler()->CodeSize();
+    __ Jmp(&StubCode::DeoptimizeLazyLabel(), PP);
+  }
 }
 
 
 void FlowGraphCompiler::GenerateCall(intptr_t token_pos,
                                      const ExternalLabel* label,
                                      PcDescriptors::Kind kind,
                                      LocationSummary* locs) {
   __ Call(label, PP);
   AddCurrentDescriptor(kind, Isolate::kNoDeoptId, token_pos);
   RecordSafepoint(locs);
@@ skipping 608 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ AddImmediate(RSP, Immediate(kFpuRegisterSize), PP);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64