[crankshaft] TODO bankruptcy.

R=verwaest@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1694643004

Cr-Commit-Position: refs/heads/master@{#33982}

src/crankshaft/hydrogen-alias-analysis.h

@@ -44,7 +44,6 @@ class HAliasAnalyzer : public ZoneObject {
 
     // Constant objects can be distinguished statically.
     if (a->IsConstant()) {
-      // TODO(titzer): DataEquals() is more efficient, but that's protected.
       return a->Equals(b) ? kMustAlias : kNoAlias;
     }
     return kMayAlias;

src/crankshaft/hydrogen-instructions.cc

@@ -765,7 +765,6 @@ void HInstruction::Verify() {
 
 
 bool HInstruction::CanDeoptimize() {
-  // TODO(titzer): make this a virtual method?
   switch (opcode()) {
     case HValue::kAbnormalExit:
     case HValue::kAccessArgumentsAt:
@@ -2731,7 +2730,6 @@ HConstant::HConstant(Handle<Object> object, Representation r)
         bit_field_, has_int32_value && Smi::IsValid(int32_value_));
     double_value_ = n;
     bit_field_ = HasDoubleValueField::update(bit_field_, true);
-    // TODO(titzer): if this heap number is new space, tenure a new one.
   }
 
   Initialize(r);
@@ -2904,7 +2902,6 @@ bool HConstant::EmitAtUses() {
   DCHECK(IsLinked());
   if (block()->graph()->has_osr() &&
       block()->graph()->IsStandardConstant(this)) {
-    // TODO(titzer): this seems like a hack that should be fixed by custom OSR.
     return true;
   }
   if (HasNoUses()) return true;

src/crankshaft/hydrogen-instructions.h

@@ -2789,8 +2789,6 @@ class HCheckValue final : public HUnaryOperation {
     bool in_new_space = isolate->heap()->InNewSpace(*func);
     // NOTE: We create an uninitialized Unique and initialize it later.
     // This is because a JSFunction can move due to GC during graph creation.
-    // TODO(titzer): This is a migration crutch. Replace with some kind of
-    // Uniqueness scope later.
     Unique<JSFunction> target = Unique<JSFunction>::CreateUninitialized(func);
     HCheckValue* check = new(zone) HCheckValue(value, target, in_new_space);
     return check;
@@ -3320,7 +3318,6 @@ class HPhi final : public HValue {
   Representation representation_from_non_phi_uses_ = Representation::None();
   bool has_type_feedback_from_uses_ = false;
 
-  // TODO(titzer): we can't eliminate the receiver for generating backtraces
   bool IsDeletable() const override { return !IsReceiver(); }
 };
 

src/crankshaft/hydrogen-load-elimination.cc

@@ -243,7 +243,6 @@ class HLoadEliminationTable : public ZoneObject {
     if (instr->has_transition()) {
       // A transition introduces a new field and alters the map of the object.
       // Since the field in the object is new, it cannot alias existing entries.
-      // TODO(titzer): introduce a constant for the new map and remember it.
       KillFieldInternal(object, FieldOf(JSObject::kMapOffset), NULL);
     } else {
       // Kill non-equivalent may-alias entries.
@@ -402,7 +401,6 @@ class HLoadEliminationTable : public ZoneObject {
   // Compute the field index for the given in-object offset; -1 if not tracked.
   int FieldOf(int offset) {
     if (offset >= kMaxTrackedFields * kPointerSize) return -1;
-    // TODO(titzer): track misaligned loads in a separate list?
     if ((offset % kPointerSize) != 0) return -1;  // Ignore misaligned accesses.
     return offset / kPointerSize;
   }

src/crankshaft/hydrogen-store-elimination.cc

@@ -36,7 +36,6 @@ void HStoreEliminationPhase::Run() {
       HInstruction* instr = it.Current();
       if (instr->CheckFlag(HValue::kIsDead)) continue;
 
-      // TODO(titzer): eliminate unobserved HStoreKeyed instructions too.
       switch (instr->opcode()) {
         case HValue::kStoreNamedField:
           // Remove any unobserved stores overwritten by this store.
@@ -68,7 +67,6 @@ void HStoreEliminationPhase::ProcessStore(HStoreNamedField* store) {
              prev->id(), store->id()));
       unobserved_.Remove(i);
     } else {
-      // TODO(titzer): remove map word clearing from folded allocations.
       i++;
     }
   }