Move deopt reason into PcDescriptor so the EAX/RAX register is not destroyed. Some cleanups in PC d…

runtime/vm/code_generator.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/code_generator.h"
 
 #include "vm/assembler_macros.h"
 #include "vm/ast.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
@@ skipping 1371 matching lines @@
 #define DEOPT_REASON_ID_TO_TEXT(name) case k##name: return #name;
 DEOPT_REASONS(DEOPT_REASON_ID_TO_TEXT)
 #undef DEOPT_REASON_ID_TO_TEXT
     default:
       UNREACHABLE();
       return "";
   }
 }
 
 
-static intptr_t GetDeoptInfo(const Code& code, uword pc) {
+static void GetDeoptInfo(const Code& code,
+                         uword pc,
+                         intptr_t* deopt_id,
+                         intptr_t* deopt_reason) {
   const PcDescriptors& descriptors =
       PcDescriptors::Handle(code.pc_descriptors());
   ASSERT(!descriptors.IsNull());
   // Locate deopt id at deoptimization point inside optimized code.
   for (int i = 0; i < descriptors.Length(); i++) {
-    if (static_cast<uword>(descriptors.PC(i)) == pc) {
-      return descriptors.DeoptId(i);
+    if ((static_cast<uword>(descriptors.PC(i)) == pc) &&
+        (descriptors.DescriptorKind(i) == PcDescriptors::kDeoptIndex)) {
+      *deopt_id = descriptors.DeoptId(i);
+      *deopt_reason = descriptors.DeoptReason(i);
+      return;
     }
   }
-  return Isolate::kNoDeoptId;
+  *deopt_id = Isolate::kNoDeoptId;
+  *deopt_reason = kDeoptUnknown;
 }
 
 
 // Copy saved registers and caller's frame into temporary buffers.
 // Access the deopt information for the deoptimization point.
 // Return the new stack size (including PC marker and deopt return address,
 // excluding FP).
 DEFINE_LEAF_RUNTIME_ENTRY(intptr_t, DeoptimizeCopyFrame,
-                          intptr_t deopt_reason,
                           intptr_t* saved_registers_address) {
   Isolate* isolate = Isolate::Current();
   Zone zone(isolate);
   HANDLESCOPE(isolate);
 
   const uword last_fp =
       reinterpret_cast<uword>(saved_registers_address + kNumberOfCpuRegisters);
   // Copy saved registers.
   intptr_t* registers_copy = new intptr_t[kNumberOfCpuRegisters];
   ASSERT(registers_copy != NULL);
   ASSERT(saved_registers_address != NULL);
   for (intptr_t i = 0; i < kNumberOfCpuRegisters; i++) {
     registers_copy[i] = *saved_registers_address;
     saved_registers_address++;
   }
   isolate->set_deopt_registers_copy(registers_copy);
   ASSERT(reinterpret_cast<uword>(saved_registers_address) == last_fp);
   DartFrameIterator iterator(last_fp);
   StackFrame* caller_frame = iterator.NextFrame();
   ASSERT(caller_frame != NULL);
   const Code& optimized_code = Code::Handle(caller_frame->LookupDartCode());
   ASSERT(optimized_code.is_optimized());
 
-  const intptr_t deopt_id = GetDeoptInfo(optimized_code, caller_frame->pc());
+  intptr_t deopt_id, deopt_reason;
+  GetDeoptInfo(optimized_code, caller_frame->pc(), &deopt_id, &deopt_reason);
   ASSERT(deopt_id != Isolate::kNoDeoptId);
 
   // Add incoming arguments.
   const Function& function = Function::Handle(optimized_code.function());
   // Think of copied arguments.
   const intptr_t num_args = (function.num_optional_parameters() > 0) ?
       0 : function.num_fixed_parameters();
   // FP, PC marker and return address will all be copied.
   const intptr_t frame_copy_size =
       1  // Deoptimized function's return address: caller_frame->pc().
@@ skipping 39 matching lines @@
   const Code& optimized_code = Code::Handle(caller_frame->LookupDartCode());
   const Function& function = Function::Handle(optimized_code.function());
   ASSERT(!function.IsNull());
   const Code& unoptimized_code = Code::Handle(function.unoptimized_code());
   ASSERT(!optimized_code.IsNull() && optimized_code.is_optimized());
   ASSERT(!unoptimized_code.IsNull() && !unoptimized_code.is_optimized());
 
   intptr_t* frame_copy = isolate->deopt_frame_copy();
   intptr_t* registers_copy = isolate->deopt_registers_copy();
 
-  intptr_t deopt_id = GetDeoptInfo(optimized_code, caller_frame->pc());
+  intptr_t deopt_id, deopt_reason;
+  GetDeoptInfo(optimized_code, caller_frame->pc(), &deopt_id, &deopt_reason);
   ASSERT(deopt_id != Isolate::kNoDeoptId);
   uword continue_at_pc = unoptimized_code.GetDeoptPcAtDeoptId(deopt_id);
   if (FLAG_trace_deopt) {
     OS::Print("  -> continue at 0x%x\n", continue_at_pc);
     // TODO(srdjan): If we could allow GC, we could print the line where
     // deoptimization occured.
   }
   const intptr_t deopt_frame_copy_size = isolate->deopt_frame_copy_size();
   // TODO(srdjan): Use deopt info to copy the values to right place.
   const intptr_t pc_marker_index =
@@ skipping 105 matching lines @@
       }
     }
   }
   // The cache is null terminated, therefore the loop above should never
   // terminate by itself.
   UNREACHABLE();
   return Code::null();
 }
 
 }  // namespace dart