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Unified Diff: src/arm/lithium-codegen-arm.cc

Issue 6324003: Move class LGapResolver to the platform specific backend implementation files. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Created 9 years, 11 months ago
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Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 5d4745c437d4ee7fed7cbdc7ded19c8fab9c4b26..7b1d896906b2da0a7740ee3b4075c2e670570949 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -54,6 +54,157 @@ class SafepointGenerator : public PostCallGenerator {
};
+class LGapNode: public ZoneObject {
+ public:
+ explicit LGapNode(LOperand* operand)
+ : operand_(operand), resolved_(false), visited_id_(-1) { }
+
+ LOperand* operand() const { return operand_; }
+ bool IsResolved() const { return !IsAssigned() || resolved_; }
+ void MarkResolved() {
+ ASSERT(!IsResolved());
+ resolved_ = true;
+ }
+ int visited_id() const { return visited_id_; }
+ void set_visited_id(int id) {
+ ASSERT(id > visited_id_);
+ visited_id_ = id;
+ }
+
+ bool IsAssigned() const { return assigned_from_.is_set(); }
+ LGapNode* assigned_from() const { return assigned_from_.get(); }
+ void set_assigned_from(LGapNode* n) { assigned_from_.set(n); }
+
+ private:
+ LOperand* operand_;
+ SetOncePointer<LGapNode> assigned_from_;
+ bool resolved_;
+ int visited_id_;
+};
+
+
+LGapResolver::LGapResolver()
+ : nodes_(32),
+ identified_cycles_(4),
+ result_(16),
+ next_visited_id_(0) {
+}
+
+
+const ZoneList<LMoveOperands>* LGapResolver::Resolve(
+ const ZoneList<LMoveOperands>* moves,
+ LOperand* marker_operand) {
+ nodes_.Rewind(0);
+ identified_cycles_.Rewind(0);
+ result_.Rewind(0);
+ next_visited_id_ = 0;
+
+ for (int i = 0; i < moves->length(); ++i) {
+ LMoveOperands move = moves->at(i);
+ if (!move.IsRedundant()) RegisterMove(move);
+ }
+
+ for (int i = 0; i < identified_cycles_.length(); ++i) {
+ ResolveCycle(identified_cycles_[i], marker_operand);
+ }
+
+ int unresolved_nodes;
+ do {
+ unresolved_nodes = 0;
+ for (int j = 0; j < nodes_.length(); j++) {
+ LGapNode* node = nodes_[j];
+ if (!node->IsResolved() && node->assigned_from()->IsResolved()) {
+ AddResultMove(node->assigned_from(), node);
+ node->MarkResolved();
+ }
+ if (!node->IsResolved()) ++unresolved_nodes;
+ }
+ } while (unresolved_nodes > 0);
+ return &result_;
+}
+
+
+void LGapResolver::AddResultMove(LGapNode* from, LGapNode* to) {
+ AddResultMove(from->operand(), to->operand());
+}
+
+
+void LGapResolver::AddResultMove(LOperand* from, LOperand* to) {
+ result_.Add(LMoveOperands(from, to));
+}
+
+
+void LGapResolver::ResolveCycle(LGapNode* start, LOperand* marker_operand) {
+ ZoneList<LOperand*> cycle_operands(8);
+ cycle_operands.Add(marker_operand);
+ LGapNode* cur = start;
+ do {
+ cur->MarkResolved();
+ cycle_operands.Add(cur->operand());
+ cur = cur->assigned_from();
+ } while (cur != start);
+ cycle_operands.Add(marker_operand);
+
+ for (int i = cycle_operands.length() - 1; i > 0; --i) {
+ LOperand* from = cycle_operands[i];
+ LOperand* to = cycle_operands[i - 1];
+ AddResultMove(from, to);
+ }
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b, int visited_id) {
+ ASSERT(a != b);
+ LGapNode* cur = a;
+ while (cur != b && cur->visited_id() != visited_id && cur->IsAssigned()) {
+ cur->set_visited_id(visited_id);
+ cur = cur->assigned_from();
+ }
+
+ return cur == b;
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b) {
+ ASSERT(a != b);
+ return CanReach(a, b, next_visited_id_++);
+}
+
+
+void LGapResolver::RegisterMove(LMoveOperands move) {
+ if (move.from()->IsConstantOperand()) {
+ // Constant moves should be last in the machine code. Therefore add them
+ // first to the result set.
+ AddResultMove(move.from(), move.to());
+ } else {
+ LGapNode* from = LookupNode(move.from());
+ LGapNode* to = LookupNode(move.to());
+ if (to->IsAssigned() && to->assigned_from() == from) {
+ move.Eliminate();
+ return;
+ }
+ ASSERT(!to->IsAssigned());
+ if (CanReach(from, to)) {
+ // This introduces a cycle. Save.
+ identified_cycles_.Add(from);
+ }
+ to->set_assigned_from(from);
+ }
+}
+
+
+LGapNode* LGapResolver::LookupNode(LOperand* operand) {
+ for (int i = 0; i < nodes_.length(); ++i) {
+ if (nodes_[i]->operand()->Equals(operand)) return nodes_[i];
+ }
+
+ // No node found => create a new one.
+ LGapNode* result = new LGapNode(operand);
+ nodes_.Add(result);
+ return result;
+}
+
+
#define __ masm()->
bool LCodeGen::GenerateCode() {
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