Deoptimization support in inlined code.

runtime/vm/flow_graph_allocator.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/flow_graph_allocator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/intermediate_language.h"
 #include "vm/il_printer.h"
 #include "vm/flow_graph.h"
@@ skipping 131 matching lines @@
       // Handle uses.
       for (intptr_t j = 0; j < current->InputCount(); j++) {
         Value* input = current->InputAt(j);
         const intptr_t use = input->definition()->ssa_temp_index();
         live_in->Add(use);
       }
 
       // Add non-argument uses from the deoptimization environment (pushed
       // arguments are not allocated by the register allocator).
       if (current->env() != NULL) {
-        for (intptr_t i = 0; i < current->env()->Length(); ++i) {
-          Value* value = current->env()->ValueAt(i);
+        for (Environment::DeepIterator env_it(current->env());
+             !env_it.Done();
+             env_it.Advance()) {
+          Value* value = env_it.CurrentValue();
           if (!value->definition()->IsPushArgument()) {
             live_in->Add(value->definition()->ssa_temp_index());
           }
         }
       }
     }
 
     // Handle phis.
     if (block->IsJoinEntry()) {
       JoinEntryInstr* join = block->AsJoinEntry();
@@ skipping 564 matching lines @@
       AssignSafepoints(range);
 
       CompleteRange(range, RegisterKindForResult(phi));
 
       move_idx++;
     }
   }
 }
 
 
-void FlowGraphAllocator::ProcessEnvironmentUses(BlockEntryInstr* block,
-                                                Instruction* current) {
-  ASSERT(current->env() != NULL);
+void FlowGraphAllocator::ProcessEnvironmentUsesRecursive(BlockEntryInstr* block,
+                                                         Instruction* current,
+                                                         Environment* env) {
+  if (env == NULL) return;
 
-  Environment* env = current->env();
+  if (env->outer() != NULL) {

[Kevin Millikin (Google), 2012/09/18 11:01:55]

The base of the recursion handles env == NULL, so no need to test (or: you can
assert env is not NULL instead of checking for NULL an returning).

It is probably better to turn this into a while loop, since it doesn't seem to
matter which order we process the environments.

[zerny-google, 2012/09/18 11:53:07]

Done.

+    ProcessEnvironmentUsesRecursive(block, current, env->outer());
+  }
 
   // Any value mentioned in the deoptimization environment should survive
   // until the end of instruction but it does not need to be in the register.
   // Expected shape of live range:
   //
   //                 i  i'
   //      value    -----*
   //
 
   if (env->Length() == 0) return;
@@ skipping 24 matching lines @@
     const intptr_t vreg = def->ssa_temp_index();
     LiveRange* range = GetLiveRange(vreg);
     range->AddUseInterval(block_start_pos, use_pos);
     range->AddUse(use_pos, &locations[i]);
   }
 
   env->set_locations(locations);
 }
 
 
+void FlowGraphAllocator::ProcessEnvironmentUses(BlockEntryInstr* block,
+                                                Instruction* current) {
+  ASSERT(current->env() != NULL);
+  ProcessEnvironmentUsesRecursive(block, current, current->env());
+}
+
+
 // Create and update live ranges corresponding to instruction's inputs,
 // temporaries and output.
 void FlowGraphAllocator::ProcessOneInstruction(BlockEntryInstr* block,
                                                Instruction* current) {
   LocationSummary* locs = current->locs();
 
   Definition* def = current->AsDefinition();
   if ((def != NULL) &&
       (def->AsConstant() != NULL) &&
       (GetLiveRange(def->ssa_temp_index())->first_use() == NULL)) {
@@ skipping 1409 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart