Revision: 12370
Author: [email protected]
Date: Thu Aug 23 01:15:38 2012
Log: Make the performance of the VM more predictable by not letting
the hash seed
affect the order in which the local variables are processed in the compiler.
Review URL: https://chromiumcodereview.appspot.com/10870033
http://code.google.com/p/v8/source/detail?r=12370
Modified:
/branches/bleeding_edge/src/hashmap.h
/branches/bleeding_edge/src/scopes.cc
/branches/bleeding_edge/src/variables.h
=======================================
--- /branches/bleeding_edge/src/hashmap.h Mon Jun 11 05:42:31 2012
+++ /branches/bleeding_edge/src/hashmap.h Thu Aug 23 01:15:38 2012
@@ -59,7 +59,8 @@
struct Entry {
void* key;
void* value;
- uint32_t hash; // the full hash value for key
+ uint32_t hash; // The full hash value for key
+ int order; // If you never remove entries this is the insertion order.
};
// If an entry with matching key is found, Lookup()
@@ -140,6 +141,7 @@
p->key = key;
p->value = NULL;
p->hash = hash;
+ p->order = occupancy_;
occupancy_++;
// Grow the map if we reached >= 80% occupancy.
@@ -297,7 +299,9 @@
// Rehash all current entries.
for (Entry* p = map; n > 0; p++) {
if (p->key != NULL) {
- Lookup(p->key, p->hash, true, allocator)->value = p->value;
+ Entry* entry = Lookup(p->key, p->hash, true, allocator);
+ entry->value = p->value;
+ entry->order = p->order;
n--;
}
}
=======================================
--- /branches/bleeding_edge/src/scopes.cc Fri Aug 17 02:03:08 2012
+++ /branches/bleeding_edge/src/scopes.cc Thu Aug 23 01:15:38 2012
@@ -594,6 +594,21 @@
}
+class VarAndOrder {
+ public:
+ VarAndOrder(Variable* var, int order) : var_(var), order_(order) { }
+ Variable* var() const { return var_; }
+ int order() const { return order_; }
+ static int Compare(const VarAndOrder* a, const VarAndOrder* b) {
+ return a->order_ - b->order_;
+ }
+
+ private:
+ Variable* var_;
+ int order_;
+};
+
+
void Scope::CollectStackAndContextLocals(ZoneList<Variable*>* stack_locals,
ZoneList<Variable*>*
context_locals) {
ASSERT(stack_locals != NULL);
@@ -607,6 +622,8 @@
stack_locals->Add(var, zone());
}
}
+
+ ZoneList<VarAndOrder> vars(variables_.occupancy(), zone());
// Collect declared local variables.
for (VariableMap::Entry* p = variables_.Start();
@@ -614,11 +631,17 @@
p = variables_.Next(p)) {
Variable* var = reinterpret_cast<Variable*>(p->value);
if (var->is_used()) {
- if (var->IsStackLocal()) {
- stack_locals->Add(var, zone());
- } else if (var->IsContextSlot()) {
- context_locals->Add(var, zone());
- }
+ vars.Add(VarAndOrder(var, p->order), zone());
+ }
+ }
+ vars.Sort(VarAndOrder::Compare);
+ int var_count = vars.length();
+ for (int i = 0; i < var_count; i++) {
+ Variable* var = vars[i].var();
+ if (var->IsStackLocal()) {
+ stack_locals->Add(var, zone());
+ } else if (var->IsContextSlot()) {
+ context_locals->Add(var, zone());
}
}
}
@@ -1255,12 +1278,20 @@
for (int i = 0; i < temps_.length(); i++) {
AllocateNonParameterLocal(temps_[i]);
}
+
+ ZoneList<VarAndOrder> vars(variables_.occupancy(), zone());
for (VariableMap::Entry* p = variables_.Start();
p != NULL;
p = variables_.Next(p)) {
Variable* var = reinterpret_cast<Variable*>(p->value);
- AllocateNonParameterLocal(var);
+ vars.Add(VarAndOrder(var, p->order), zone());
+ }
+
+ vars.Sort(VarAndOrder::Compare);
+ int var_count = vars.length();
+ for (int i = 0; i < var_count; i++) {
+ AllocateNonParameterLocal(vars[i].var());
}
// For now, function_ must be allocated at the very end. If it gets
=======================================
--- /branches/bleeding_edge/src/variables.h Thu Mar 8 05:03:07 2012
+++ /branches/bleeding_edge/src/variables.h Thu Aug 23 01:15:38 2012
@@ -55,7 +55,7 @@
UNALLOCATED,
// A slot in the parameter section on the stack. index() is the
- // parameter index, counting left-to-right. The reciever is index -1;
+ // parameter index, counting left-to-right. The receiver is index -1;
// the first parameter is index 0.
PARAMETER,
--
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