commit 77520bca97ec44e3758510cebd0f20e3bb4584ea
author Calin Juravle <calin@google.com> Mon Jan 12 18:45:46 2015 +0000
committer Calin Juravle <calin@google.com> Wed Jan 21 14:26:35 2015 +0000
tree 2e3be6fdc182e5cf5ae390019457af5e9c1ed242
parent 4d2c611bf17ff309abfa152e56c0b98a21ec8787

Record implicit null checks at the actual invoke time.

ImplicitNullChecks are recorded only for instructions directly (see NB
below) preceeded by NullChecks in the graph. This way we avoid recording
redundant safepoints and minimize the code size increase.

NB: ParallalelMoves might be inserted by the register allocator between
the NullChecks and their uses. These modify the environment and the
correct action would be to reverse their modification. This will be
addressed in a follow-up CL.

Change-Id: Ie50006e5a4bd22932dcf11348f5a655d253cd898

compiler/optimizing/code_generator_x86_64.cc

diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index dd6861f..350392f 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -1244,6 +1244,7 @@
   } else {
     __ movl(temp, Address(receiver.AsRegister<CpuRegister>(), class_offset));
   }
+  codegen_->MaybeRecordImplicitNullCheck(invoke);
   // temp = temp->GetMethodAt(method_offset);
   __ movl(temp, Address(temp, method_offset));
   // call temp->GetEntryPoint();
@@ -1280,6 +1281,7 @@
   } else {
     __ movl(temp, Address(receiver.AsRegister<CpuRegister>(), class_offset));
   }
+  codegen_->MaybeRecordImplicitNullCheck(invoke);
   // temp = temp->GetImtEntryAt(method_offset);
   __ movl(temp, Address(temp, method_offset));
   // call temp->GetEntryPoint();
@@ -2589,6 +2591,8 @@
       UNREACHABLE();
   }
 
+  codegen_->MaybeRecordImplicitNullCheck(instruction);
+
   if (is_volatile) {
     GenerateMemoryBarrier(MemBarrierKind::kLoadAny);
   }
@@ -2643,11 +2647,6 @@
     case Primitive::kPrimInt:
     case Primitive::kPrimNot: {
       __ movl(Address(base, offset), value.AsRegister<CpuRegister>());
-      if (CodeGenerator::StoreNeedsWriteBarrier(field_type, instruction->InputAt(1))) {
-        CpuRegister temp = locations->GetTemp(0).AsRegister<CpuRegister>();
-        CpuRegister card = locations->GetTemp(1).AsRegister<CpuRegister>();
-        codegen_->MarkGCCard(temp, card, base, value.AsRegister<CpuRegister>());
-      }
       break;
     }
 
@@ -2671,6 +2670,14 @@
       UNREACHABLE();
   }
 
+  codegen_->MaybeRecordImplicitNullCheck(instruction);
+
+  if (CodeGenerator::StoreNeedsWriteBarrier(field_type, instruction->InputAt(1))) {
+    CpuRegister temp = locations->GetTemp(0).AsRegister<CpuRegister>();
+    CpuRegister card = locations->GetTemp(1).AsRegister<CpuRegister>();
+    codegen_->MarkGCCard(temp, card, base, value.AsRegister<CpuRegister>());
+  }
+
   if (is_volatile) {
     GenerateMemoryBarrier(MemBarrierKind::kAnyAny);
   }
@@ -2721,6 +2728,9 @@
 }
 
 void InstructionCodeGeneratorX86_64::GenerateImplicitNullCheck(HNullCheck* instruction) {
+  if (codegen_->CanMoveNullCheckToUser(instruction)) {
+    return;
+  }
   LocationSummary* locations = instruction->GetLocations();
   Location obj = locations->InAt(0);
 
@@ -2873,6 +2883,7 @@
       LOG(FATAL) << "Unreachable type " << instruction->GetType();
       UNREACHABLE();
   }
+  codegen_->MaybeRecordImplicitNullCheck(instruction);
 }
 
 void LocationsBuilderX86_64::VisitArraySet(HArraySet* instruction) {
@@ -2941,6 +2952,7 @@
                   Immediate(value.GetConstant()->AsIntConstant()->GetValue()));
         }
       }
+      codegen_->MaybeRecordImplicitNullCheck(instruction);
       break;
     }
 
@@ -2967,6 +2979,7 @@
                   Immediate(value.GetConstant()->AsIntConstant()->GetValue()));
         }
       }
+      codegen_->MaybeRecordImplicitNullCheck(instruction);
       break;
     }
 
@@ -2995,7 +3008,7 @@
                     Immediate(value.GetConstant()->AsIntConstant()->GetValue()));
           }
         }
-
+        codegen_->MaybeRecordImplicitNullCheck(instruction);
         if (needs_write_barrier) {
           DCHECK_EQ(value_type, Primitive::kPrimNot);
           CpuRegister temp = locations->GetTemp(0).AsRegister<CpuRegister>();
@@ -3023,6 +3036,7 @@
         __ movq(Address(obj, index.AsRegister<CpuRegister>(), TIMES_8, data_offset),
                 value.AsRegister<CpuRegister>());
       }
+      codegen_->MaybeRecordImplicitNullCheck(instruction);
       break;
     }
 
@@ -3037,6 +3051,7 @@
         __ movss(Address(obj, index.AsRegister<CpuRegister>(), TIMES_4, data_offset),
                 value.AsFpuRegister<XmmRegister>());
       }
+      codegen_->MaybeRecordImplicitNullCheck(instruction);
       break;
     }
 
@@ -3051,6 +3066,7 @@
         __ movsd(Address(obj, index.AsRegister<CpuRegister>(), TIMES_8, data_offset),
                 value.AsFpuRegister<XmmRegister>());
       }
+      codegen_->MaybeRecordImplicitNullCheck(instruction);
       break;
     }
 
@@ -3073,6 +3089,7 @@
   CpuRegister obj = locations->InAt(0).AsRegister<CpuRegister>();
   CpuRegister out = locations->Out().AsRegister<CpuRegister>();
   __ movl(out, Address(obj, offset));
+  codegen_->MaybeRecordImplicitNullCheck(instruction);
 }
 
 void LocationsBuilderX86_64::VisitBoundsCheck(HBoundsCheck* instruction) {