Remove deoptimization index PC descriptors.

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 1409 matching lines @@
     if (FLAG_trace_patching) {
       OS::Print("FixCallersTarget: patching from %#"Px" to '%s' %#"Px"\n",
           frame->pc(),
           target_function.ToFullyQualifiedCString(),
           new_entry_point);
     }
   }
 }
 
 
-static const char* DeoptReasonToText(intptr_t deopt_id) {
+const char* DeoptReasonToText(intptr_t deopt_id) {
   switch (deopt_id) {
-#define DEOPT_REASON_ID_TO_TEXT(name) case k##name: return #name;
+#define DEOPT_REASON_ID_TO_TEXT(name) case kDeopt##name: return #name;
 DEOPT_REASONS(DEOPT_REASON_ID_TO_TEXT)
 #undef DEOPT_REASON_ID_TO_TEXT
     default:
       UNREACHABLE();
       return "";
   }
 }
 
 
-static void GetDeoptIxDescrAtPc(const Code& code,
-                                uword pc,
-                                intptr_t* deopt_id,
-                                intptr_t* deopt_reason,
-                                intptr_t* deopt_index) {
+static void GetDeoptInfoAtPc(const Code& code,
+                             uword pc,
+                             DeoptInfo* deopt_info,
+                             intptr_t* deopt_reason) {
   ASSERT(code.is_optimized());
-  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) &&
-        (descriptors.DescriptorKind(i) == PcDescriptors::kDeoptIndex)) {
-      *deopt_id = descriptors.DeoptId(i);
-      *deopt_reason = descriptors.DeoptReason(i);
-      *deopt_index = descriptors.DeoptIndex(i);
+  const Instructions& instructions = Instructions::Handle(code.instructions());
+  uword code_entry = instructions.EntryPoint();
+  const Array& deopt_info_array = Array::Handle(code.deopt_info_array());
+  ASSERT(!deopt_info_array.IsNull());
+  // Linear search for the PC offset matching the target PC.
+  // An entry is a triple of (pc_offset, deopt_info, deopt_reason).
+  const intptr_t kEntrySize = 3;
+  Smi& offset = Smi::Handle();
+  for (intptr_t i = 0; i < deopt_info_array.Length(); i += kEntrySize) {
+    offset ^= deopt_info_array.At(i);
+    if (pc == (code_entry + offset.Value())) {
+      *deopt_info ^= deopt_info_array.At(i + 1);
+      *deopt_reason =
+          Smi::Cast(Object::Handle(deopt_info_array.At(i + 2))).Value();
       return;
     }
   }

[srdjan, 2012/09/28 21:00:26]

Iniitialize deopt_info and deopt_reason to something reasonable if the info is
not found.

[Kevin Millikin (Google), 2012/10/01 09:38:56]

OK, done.

[srdjan, 2012/10/01 17:18:28]

Please upload your changes, before submitting, so that I can see them. Thanks!

-  *deopt_id = Isolate::kNoDeoptId;
-  *deopt_reason = kDeoptUnknown;
-  *deopt_index = -1;
 }
 
 
 // Currently checks only that all optimized frames have kDeoptIndex
 // and unoptimized code has the kDeoptAfter.
 void DeoptimizeAll() {
   DartFrameIterator iterator;
   StackFrame* frame = iterator.NextFrame();
   Code& optimized_code = Code::Handle();
   Function& function = Function::Handle();
   Code& unoptimized_code = Code::Handle();
   while (frame != NULL) {
     optimized_code = frame->LookupDartCode();
     if (optimized_code.is_optimized()) {
-      intptr_t deopt_id, deopt_reason, deopt_index;
-      GetDeoptIxDescrAtPc(optimized_code, frame->pc(),
-                          &deopt_id, &deopt_reason, &deopt_index);
-      ASSERT(deopt_id != Isolate::kNoDeoptId);
+      DeoptInfo& deopt_info = DeoptInfo::Handle();
+      intptr_t deopt_reason = kDeoptUnknown;
+      GetDeoptInfoAtPc(optimized_code, frame->pc(), &deopt_info, &deopt_reason);
+      ASSERT(!deopt_info.IsNull());
       function = optimized_code.function();
       unoptimized_code = function.unoptimized_code();
       ASSERT(!unoptimized_code.IsNull());
       // The switch to unoptimized code may have already occured.
       if (function.HasOptimizedCode()) {
         function.SwitchToUnoptimizedCode();
       }
       // Patch call site (lazy deoptimization is quite rare, patching it twice
       // is not a performance issue).
       uword lazy_deopt_jump = optimized_code.GetLazyDeoptPc();
@@ skipping 68 matching lines @@
       kNumberOfCpuRegisters * kWordSize + kNumberOfXmmRegisters * kDoubleSize;
   CopySavedRegisters(saved_registers_address);
 
   // Get optimized code and frame that need to be deoptimized.
   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());
 
-  intptr_t deopt_id, deopt_reason, deopt_index;
-  GetDeoptIxDescrAtPc(optimized_code, caller_frame->pc(),
-                      &deopt_id, &deopt_reason, &deopt_index);
-  ASSERT(deopt_id != Isolate::kNoDeoptId);
+
+  DeoptInfo& deopt_info = DeoptInfo::Handle();
+  intptr_t deopt_reason = kDeoptUnknown;
+  GetDeoptInfoAtPc(optimized_code, caller_frame->pc(), &deopt_info,
+                   &deopt_reason);
+  ASSERT(!deopt_info.IsNull());
 
   CopyFrame(optimized_code, *caller_frame);
   if (FLAG_trace_deopt) {
-    intptr_t deopt_id, deopt_reason, deopt_index;
-    GetDeoptIxDescrAtPc(optimized_code, caller_frame->pc(),
-                        &deopt_id, &deopt_reason, &deopt_index);
-    OS::Print("Deoptimizing (reason %"Pd" '%s') at pc %#"Px" id %"Pd" '%s'\n",
+    OS::Print("Deoptimizing (reason %"Pd" '%s') at pc %#"Px" '%s'\n",
         deopt_reason,
         DeoptReasonToText(deopt_reason),
         caller_frame->pc(),
-        deopt_id,
         Function::Handle(optimized_code.function()).ToFullyQualifiedCString());
   }
 
-  // Compute the stack size of unoptimized frame
-  const Array& deopt_info_array =
-      Array::Handle(optimized_code.deopt_info_array());
-  ASSERT(!deopt_info_array.IsNull());
-  DeoptInfo& deopt_info = DeoptInfo::Handle();
-  deopt_info ^= deopt_info_array.At(deopt_index);
-  ASSERT(!deopt_info.IsNull());
-  // For functions with optional argument deoptimization info does not
-  // describe incoming arguments.
+  // Compute the stack size of the unoptimized frame.  For functions with
+  // optional arguments the deoptimization info does not describe the
+  // incoming arguments.
   const Function& function = Function::Handle(optimized_code.function());
   const intptr_t num_args =
       function.HasOptionalParameters() ? 0 : function.num_fixed_parameters();
   intptr_t unoptimized_stack_size =
       + deopt_info.Length() - num_args
       - 2;  // Subtract caller FP and PC.
   return unoptimized_stack_size * kWordSize;
 }
 END_LEAF_RUNTIME_ENTRY
 
@@ skipping 52 matching lines @@
   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* cpu_registers_copy = isolate->deopt_cpu_registers_copy();
   double* xmm_registers_copy = isolate->deopt_xmm_registers_copy();
 
-  intptr_t deopt_id, deopt_reason, deopt_index;
-  GetDeoptIxDescrAtPc(optimized_code, caller_frame->pc(),
-                      &deopt_id, &deopt_reason, &deopt_index);
-  ASSERT(deopt_id != Isolate::kNoDeoptId);
-  const Array& deopt_info_array =
-      Array::Handle(optimized_code.deopt_info_array());
-  ASSERT(!deopt_info_array.IsNull());
   DeoptInfo& deopt_info = DeoptInfo::Handle();
-  deopt_info ^= deopt_info_array.At(deopt_index);
+  intptr_t deopt_reason = kDeoptUnknown;
+  GetDeoptInfoAtPc(optimized_code, caller_frame->pc(), &deopt_info,
+                   &deopt_reason);
   ASSERT(!deopt_info.IsNull());
+
   const intptr_t caller_fp =
       DeoptimizeWithDeoptInfo(optimized_code, deopt_info, *caller_frame);
 
   isolate->SetDeoptFrameCopy(NULL, 0);
   isolate->set_deopt_cpu_registers_copy(NULL);
   isolate->set_deopt_xmm_registers_copy(NULL);
   delete[] frame_copy;
   delete[] cpu_registers_copy;
   delete[] xmm_registers_copy;
 
@@ skipping 25 matching lines @@
                 current->slot(),
                 current->value());
     }
 
     delete current;
   }
 }
 
 
 }  // namespace dart