[turbofan] Treat uninitialized source positions as unknown.

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1109763002

Cr-Commit-Position: refs/heads/master@{#28399}

src/compiler/code-generator.cc

@@ -38,7 +38,7 @@ CodeGenerator::CodeGenerator(Frame* frame, Linkage* linkage,
       info_(info),
       labels_(zone()->NewArray<Label>(code->InstructionBlockCount())),
       current_block_(RpoNumber::Invalid()),
-      current_source_position_(SourcePosition::Invalid()),
+      current_source_position_(SourcePosition::Unknown()),
       masm_(info->isolate(), NULL, 0),
       resolver_(this),
       safepoints_(code->zone()),
@@ -256,11 +256,10 @@ void CodeGenerator::AssembleSourcePosition(Instruction* instr) {
   SourcePosition source_position;
   if (!code()->GetSourcePosition(instr, &source_position)) return;
   if (source_position == current_source_position_) return;
-  DCHECK(!source_position.IsInvalid());
   current_source_position_ = source_position;
   if (source_position.IsUnknown()) return;
   int code_pos = source_position.raw();
-  masm()->positions_recorder()->RecordPosition(source_position.raw());
+  masm()->positions_recorder()->RecordPosition(code_pos);
   masm()->positions_recorder()->WriteRecordedPositions();
   if (FLAG_code_comments) {
     Vector<char> buffer = Vector<char>::New(256);

src/compiler/graph-visualizer.cc

@@ -122,8 +122,7 @@ class JSONGraphNodeWriter {
       os_ << ",\"rankInputs\":[0]";
     }
     SourcePosition position = positions_->GetSourcePosition(node);
-    if (!position.IsUnknown()) {
-      DCHECK(!position.IsInvalid());
+    if (position.IsKnown()) {
       os_ << ",\"pos\":" << position.raw();
     }
     os_ << ",\"opcode\":\"" << IrOpcode::Mnemonic(node->opcode()) << "\"";
@@ -650,8 +649,7 @@ void GraphC1Visualizer::PrintSchedule(const char* phase,
         }
         if (positions != NULL) {
           SourcePosition position = positions->GetSourcePosition(node);
-          if (!position.IsUnknown()) {
-            DCHECK(!position.IsInvalid());
+          if (position.IsKnown()) {
             os_ << " pos:" << position.raw();
           }
         }

src/compiler/instruction-selector.cc

@@ -423,10 +423,9 @@ void InstructionSelector::VisitBlock(BasicBlock* block) {
     if (instructions_.size() == current_node_end) continue;
     // Mark source position on first instruction emitted.
     SourcePosition source_position = source_positions_->GetSourcePosition(node);
-    if (source_position.IsUnknown()) continue;
-    DCHECK(!source_position.IsInvalid());
-    if (source_position_mode_ == kAllSourcePositions ||
-        node->opcode() == IrOpcode::kCall) {
+    if (source_position.IsKnown() &&
+        (source_position_mode_ == kAllSourcePositions ||
+         node->opcode() == IrOpcode::kCall)) {
       sequence()->SetSourcePosition(instructions_[current_node_end],
                                     source_position);
     }

src/compiler/instruction.cc

@@ -657,8 +657,6 @@ bool InstructionSequence::GetSourcePosition(const Instruction* instr,
 
 void InstructionSequence::SetSourcePosition(const Instruction* instr,
                                             SourcePosition value) {
-  DCHECK(!value.IsInvalid());
-  DCHECK(!value.IsUnknown());
   source_positions_.insert(std::make_pair(instr, value));
 }
 

src/compiler/pipeline.cc

@@ -488,8 +488,6 @@ struct ContextSpecializerPhase {
   static const char* phase_name() { return "context specializing"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     JSContextSpecializer spec(data->jsgraph());
     GraphReducer graph_reducer(data->graph(), temp_zone);
     AddReducer(data, &graph_reducer, &spec);
@@ -502,8 +500,6 @@ struct InliningPhase {
   static const char* phase_name() { return "inlining"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     GraphReducer graph_reducer(data->graph(), temp_zone);
     JSInliner inliner(&graph_reducer, data->info()->is_inlining_enabled()
                                           ? JSInliner::kGeneralInlining
@@ -526,8 +522,6 @@ struct OsrDeconstructionPhase {
   static const char* phase_name() { return "OSR deconstruction"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     OsrHelper osr_helper(data->info());
     osr_helper.Deconstruct(data->jsgraph(), data->common(), temp_zone);
   }
@@ -538,8 +532,6 @@ struct JSTypeFeedbackPhase {
   static const char* phase_name() { return "type feedback specializing"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     Handle<Context> native_context(data->info()->context()->native_context());
     TypeFeedbackOracle oracle(data->isolate(), temp_zone,
                               data->info()->unoptimized_code(),
@@ -565,8 +557,6 @@ struct TypedLoweringPhase {
   static const char* phase_name() { return "typed lowering"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     LoadElimination load_elimination;
     JSBuiltinReducer builtin_reducer(data->jsgraph());
     JSTypedLowering typed_lowering(data->jsgraph(), temp_zone);
@@ -589,8 +579,6 @@ struct SimplifiedLoweringPhase {
   static const char* phase_name() { return "simplified lowering"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     SimplifiedLowering lowering(data->jsgraph(), temp_zone,
                                 data->source_positions());
     lowering.LowerAllNodes();
@@ -612,8 +600,6 @@ struct ControlFlowOptimizationPhase {
   static const char* phase_name() { return "control flow optimization"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     ControlFlowOptimizer optimizer(data->jsgraph(), temp_zone);
     optimizer.Optimize();
   }
@@ -624,8 +610,6 @@ struct ChangeLoweringPhase {
   static const char* phase_name() { return "change lowering"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     ValueNumberingReducer vn_reducer(temp_zone);
     SimplifiedOperatorReducer simple_reducer(data->jsgraph());
     ChangeLowering lowering(data->jsgraph());
@@ -645,8 +629,6 @@ struct ChangeLoweringPhase {
 struct EarlyControlReductionPhase {
   static const char* phase_name() { return "early control reduction"; }
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     ControlReducer::ReduceGraph(temp_zone, data->jsgraph(), 0);
   }
 };
@@ -655,8 +637,6 @@ struct EarlyControlReductionPhase {
 struct LateControlReductionPhase {
   static const char* phase_name() { return "late control reduction"; }
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     ControlReducer::ReduceGraph(temp_zone, data->jsgraph(), 0);
   }
 };
@@ -666,8 +646,6 @@ struct StressLoopPeelingPhase {
   static const char* phase_name() { return "stress loop peeling"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     // Peel the first outer loop for testing.
     // TODO(titzer): peel all loops? the N'th loop? Innermost loops?
     LoopTree* loop_tree = LoopFinder::BuildLoopTree(data->graph(), temp_zone);
@@ -683,8 +661,6 @@ struct GenericLoweringPhase {
   static const char* phase_name() { return "generic lowering"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
-    SourcePositionTable::Scope pos(data->source_positions(),
-                                   SourcePosition::Unknown());
     JSGenericLowering generic(data->info()->is_typing_enabled(),
                               data->jsgraph());
     SelectLowering select(data->jsgraph()->graph(), data->jsgraph()->common());

src/compiler/source-position.cc

@@ -16,7 +16,6 @@ class SourcePositionTable::Decorator final : public GraphDecorator {
       : source_positions_(source_positions) {}
 
   void Decorate(Node* node, bool incomplete) final {
-    DCHECK(!source_positions_->current_position_.IsInvalid());
     source_positions_->table_.Set(node, source_positions_->current_position_);
   }
 
@@ -28,7 +27,7 @@ class SourcePositionTable::Decorator final : public GraphDecorator {
 SourcePositionTable::SourcePositionTable(Graph* graph)
     : graph_(graph),
       decorator_(nullptr),
-      current_position_(SourcePosition::Invalid()),
+      current_position_(SourcePosition::Unknown()),
       table_(graph->zone()) {}
 
 
@@ -56,7 +55,7 @@ void SourcePositionTable::Print(std::ostream& os) const {
   bool needs_comma = false;
   for (auto i : table_) {
     SourcePosition pos = i.second;
-    if (!pos.IsUnknown()) {
+    if (pos.IsKnown()) {
       if (needs_comma) {
         os << ",";
       }

src/compiler/source-position.h

@@ -20,16 +20,12 @@ class SourcePosition final {
 
   static SourcePosition Unknown() { return SourcePosition(kUnknownPosition); }
   bool IsUnknown() const { return raw() == kUnknownPosition; }
-
-  static SourcePosition Invalid() { return SourcePosition(kInvalidPosition); }
-  bool IsInvalid() const { return raw() == kInvalidPosition; }
+  bool IsKnown() const { return raw() != kUnknownPosition; }
 
   int raw() const { return raw_; }
 
  private:
-  static const int kInvalidPosition = -2;
   static const int kUnknownPosition = RelocInfo::kNoPosition;
-  STATIC_ASSERT(kInvalidPosition != kUnknownPosition);
   int raw_;
 };
 
@@ -61,9 +57,7 @@ class SourcePositionTable final {
 
    private:
     void Init(SourcePosition position) {
-      if (!position.IsUnknown() || prev_position_.IsInvalid()) {
-        source_positions_->current_position_ = position;
-      }
+      if (position.IsKnown()) source_positions_->current_position_ = position;
     }
 
     SourcePositionTable* const source_positions_;