Revision: 19713
Author: [email protected]
Date: Fri Mar 7 10:14:03 2014 UTC
Log: Track global cells as special side effects in GVN.
[email protected]
Review URL: https://codereview.chromium.org/188543004
http://code.google.com/p/v8/source/detail?r=19713
Modified:
/branches/bleeding_edge/src/handles-inl.h
/branches/bleeding_edge/src/hydrogen-gvn.cc
/branches/bleeding_edge/src/hydrogen-gvn.h
/branches/bleeding_edge/src/unique.h
=======================================
--- /branches/bleeding_edge/src/handles-inl.h Thu Jan 16 08:17:40 2014 UTC
+++ /branches/bleeding_edge/src/handles-inl.h Fri Mar 7 10:14:03 2014 UTC
@@ -97,7 +97,8 @@
if (!AllowHandleDereference::IsAllowed()) return false;
if (mode == INCLUDE_DEFERRED_CHECK &&
!AllowDeferredHandleDereference::IsAllowed()) {
- // Accessing maps and internalized strings is safe.
+ // Accessing cells, maps and internalized strings is safe.
+ if (heap_object->IsCell()) return true;
if (heap_object->IsMap()) return true;
if (heap_object->IsInternalizedString()) return true;
return !heap->isolate()->IsDeferredHandle(handle);
=======================================
--- /branches/bleeding_edge/src/hydrogen-gvn.cc Tue Feb 11 06:53:14 2014 UTC
+++ /branches/bleeding_edge/src/hydrogen-gvn.cc Fri Mar 7 10:14:03 2014 UTC
@@ -367,15 +367,28 @@
SideEffects SideEffectsTracker::ComputeChanges(HInstruction* instr) {
+ int index;
SideEffects result(instr->ChangesFlags());
+ if (result.ContainsFlag(kGlobalVars)) {
+ if (instr->IsStoreGlobalCell() &&
+ ComputeGlobalVar(HStoreGlobalCell::cast(instr)->cell(), &index)) {
+ result.RemoveFlag(kGlobalVars);
+ result.AddSpecial(GlobalVar(index));
+ } else {
+ for (index = 0; index < kNumberOfGlobalVars; ++index) {
+ result.AddSpecial(GlobalVar(index));
+ }
+ }
+ }
if (result.ContainsFlag(kInobjectFields)) {
- int index;
if (instr->IsStoreNamedField() &&
ComputeInobjectField(HStoreNamedField::cast(instr)->access(),
&index)) {
result.RemoveFlag(kInobjectFields);
- result.AddSpecial(index);
+ result.AddSpecial(InobjectField(index));
} else {
- result.AddAllSpecial();
+ for (index = 0; index < kNumberOfInobjectFields; ++index) {
+ result.AddSpecial(InobjectField(index));
+ }
}
}
return result;
@@ -383,15 +396,28 @@
SideEffects SideEffectsTracker::ComputeDependsOn(HInstruction* instr) {
+ int index;
SideEffects result(instr->DependsOnFlags());
+ if (result.ContainsFlag(kGlobalVars)) {
+ if (instr->IsLoadGlobalCell() &&
+ ComputeGlobalVar(HLoadGlobalCell::cast(instr)->cell(), &index)) {
+ result.RemoveFlag(kGlobalVars);
+ result.AddSpecial(GlobalVar(index));
+ } else {
+ for (index = 0; index < kNumberOfGlobalVars; ++index) {
+ result.AddSpecial(GlobalVar(index));
+ }
+ }
+ }
if (result.ContainsFlag(kInobjectFields)) {
- int index;
if (instr->IsLoadNamedField() &&
ComputeInobjectField(HLoadNamedField::cast(instr)->access(),
&index)) {
result.RemoveFlag(kInobjectFields);
- result.AddSpecial(index);
+ result.AddSpecial(InobjectField(index));
} else {
- result.AddAllSpecial();
+ for (index = 0; index < kNumberOfInobjectFields; ++index) {
+ result.AddSpecial(InobjectField(index));
+ }
}
}
return result;
@@ -420,8 +446,15 @@
}
}
}
+ for (int index = 0; index < num_global_vars_; ++index) {
+ if (side_effects.ContainsSpecial(GlobalVar(index))) {
+ stream->Add(separator);
+ separator = ", ";
+ stream->Add("[%p]", *global_vars_[index].handle());
+ }
+ }
for (int index = 0; index < num_inobject_fields_; ++index) {
- if (side_effects.ContainsSpecial(index)) {
+ if (side_effects.ContainsSpecial(InobjectField(index))) {
stream->Add(separator);
separator = ", ";
inobject_fields_[index].PrintTo(stream);
@@ -429,6 +462,29 @@
}
stream->Add("]");
}
+
+
+bool SideEffectsTracker::ComputeGlobalVar(Unique<Cell> cell, int* index) {
+ for (int i = 0; i < num_global_vars_; ++i) {
+ if (cell == global_vars_[i]) {
+ *index = i;
+ return true;
+ }
+ }
+ if (num_global_vars_ < kNumberOfGlobalVars) {
+ if (FLAG_trace_gvn) {
+ HeapStringAllocator allocator;
+ StringStream stream(&allocator);
+ stream.Add("Tracking global var [%p] (mapped to index %d)\n",
+ *cell.handle(), num_global_vars_);
+ stream.OutputToStdOut();
+ }
+ *index = num_global_vars_;
+ global_vars_[num_global_vars_++] = cell;
+ return true;
+ }
+ return false;
+}
bool SideEffectsTracker::ComputeInobjectField(HObjectAccess access,
@@ -439,13 +495,13 @@
return true;
}
}
- if (num_inobject_fields_ < SideEffects::kNumberOfSpecials) {
+ if (num_inobject_fields_ < kNumberOfInobjectFields) {
if (FLAG_trace_gvn) {
HeapStringAllocator allocator;
StringStream stream(&allocator);
stream.Add("Tracking inobject field access ");
access.PrintTo(&stream);
- stream.Add(" (mapped to special index %d)\n", num_inobject_fields_);
+ stream.Add(" (mapped to index %d)\n", num_inobject_fields_);
stream.OutputToStdOut();
}
*index = num_inobject_fields_;
=======================================
--- /branches/bleeding_edge/src/hydrogen-gvn.h Tue Feb 11 07:05:47 2014 UTC
+++ /branches/bleeding_edge/src/hydrogen-gvn.h Fri Mar 7 10:14:03 2014 UTC
@@ -58,7 +58,6 @@
bool ContainsAnyOf(SideEffects set) const { return (bits_ &
set.bits_) != 0; }
void Add(SideEffects set) { bits_ |= set.bits_; }
void AddSpecial(int special) { bits_ |= MaskSpecial(special); }
- void AddAllSpecial() { bits_ |= ~static_cast<uint64_t>(0) <<
kNumberOfFlags; }
void RemoveFlag(GVNFlag flag) { bits_ &= ~MaskFlag(flag); }
void RemoveAll() { bits_ = 0; }
uint64_t ToIntegral() const { return bits_; }
@@ -79,21 +78,42 @@
};
-// Tracks inobject field loads/stores in a fine grained fashion, and
represents
-// them using the "special" dynamic side effects of the SideEffects class
(see
-// above). This way unrelated inobject field stores don't prevent hoisting
and
-// merging of inobject field loads.
+// Tracks global variable and inobject field loads/stores in a fine grained
+// fashion, and represents them using the "special" dynamic side effects
of the
+// SideEffects class (see above). This way unrelated global
variable/inobject
+// field stores don't prevent hoisting and merging of global
variable/inobject
+// field loads.
class SideEffectsTracker V8_FINAL BASE_EMBEDDED {
public:
- SideEffectsTracker() : num_inobject_fields_(0) {}
+ SideEffectsTracker() : num_global_vars_(0), num_inobject_fields_(0) {}
SideEffects ComputeChanges(HInstruction* instr);
SideEffects ComputeDependsOn(HInstruction* instr);
void PrintSideEffectsTo(StringStream* stream, SideEffects side_effects)
const;
private:
+ bool ComputeGlobalVar(Unique<Cell> cell, int* index);
bool ComputeInobjectField(HObjectAccess access, int* index);
- HObjectAccess inobject_fields_[SideEffects::kNumberOfSpecials];
+ static int GlobalVar(int index) {
+ ASSERT(index >= 0);
+ ASSERT(index < kNumberOfGlobalVars);
+ return index;
+ }
+ static int InobjectField(int index) {
+ ASSERT(index >= 0);
+ ASSERT(index < kNumberOfInobjectFields);
+ return index + kNumberOfGlobalVars;
+ }
+
+ // Track up to four global vars.
+ static const int kNumberOfGlobalVars = 4;
+ Unique<Cell> global_vars_[kNumberOfGlobalVars];
+ int num_global_vars_;
+
+ // Track up to n inobject fields.
+ static const int kNumberOfInobjectFields =
+ SideEffects::kNumberOfSpecials - kNumberOfGlobalVars;
+ HObjectAccess inobject_fields_[kNumberOfInobjectFields];
int num_inobject_fields_;
};
=======================================
--- /branches/bleeding_edge/src/unique.h Thu Dec 19 17:42:21 2013 UTC
+++ /branches/bleeding_edge/src/unique.h Fri Mar 7 10:14:03 2014 UTC
@@ -142,8 +142,12 @@
friend class Unique; // For comparing raw_address values.
private:
+ Unique<T>() : raw_address_(NULL) { }
+
Address raw_address_;
Handle<T> handle_;
+
+ friend class SideEffectsTracker;
};
--
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