Changeset 181498 in webkit

Timestamp:

Mar 14, 2015 10:45:43 AM (9 years ago)

Author:

commit-queue@webkit.org

Message:

Unreviewed, rolling out r181487.
​https://bugs.webkit.org/show_bug.cgi?id=142695

Caused Speedometer/Full.html to fail (Requested by smfr on
#webkit).

Reverted changeset:

"DFG::PutStackSinkingPhase should eliminate GetStacks that
have an obviously known source"
​https://bugs.webkit.org/show_bug.cgi?id=141624
​http://trac.webkit.org/changeset/181487

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• dfg/DFGPutStackSinkingPhase.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2015-03-14  Commit Queue  <commit-queue@webkit.org>
+
+        Unreviewed, rolling out r181487.
+        https://bugs.webkit.org/show_bug.cgi?id=142695
+
+        Caused Speedometer/Full.html to fail (Requested by smfr on
+        #webkit).
+
+        Reverted changeset:
+
+        "DFG::PutStackSinkingPhase should eliminate GetStacks that
+        have an obviously known source"
+        https://bugs.webkit.org/show_bug.cgi?id=141624
+        http://trac.webkit.org/changeset/181487
+
 2015-03-14  Michael Saboff  <msaboff@apple.com>
 

trunk/Source/JavaScriptCore/dfg/DFGPutStackSinkingPhase.cpp

@@ -222 +222 @@
                     }
                     
-                    if (node->op() == GetStack) {
-                        // A GetStack doesn't affect anything, since we know which local we are reading
-                        // from.
-                        continue;
-                    }
-                    
                     auto escapeHandler = [&] (VirtualRegister operand) {
                         if (operand.isHeader())
@@ -397 +391 @@
                     break;
                 }
-                    
-                case GetStack: {
-                    StackAccessData* data = node->stackAccessData();
-                    FlushFormat format = deferred.operand(data->local);
-                    if (!isConcrete(format)) {
-                        // This means there is no deferral. No deferral means that the most
-                        // authoritative value for this stack slot is what is stored in the stack. So,
-                        // keep the GetStack.
-                        break;
-                    }
-                    
-                    // We have a concrete deferral, which means a PutStack that hasn't executed yet. It
-                    // would have stored a value with a certain format. That format must match our
-                    // format. But more importantly, we can simply use the value that the PutStack would
-                    // have stored and get rid of the GetStack.
-                    DFG_ASSERT(m_graph, node, format == data->format);
-                    
-                    Node* incoming = mapping.operand(data->local);
-                    node->convertToIdentity();
-                    node->child1() = incoming->defaultEdge();
-                    break;
-                }
                 
                 default: {
@@ -447 +419 @@
                         m_graph, node, escapeHandler, escapeHandler,
                         [&] (VirtualRegister, Node*) { });
+                    
+                    // If we're a GetStack, then we also create a mapping.
+                    // FIXME: We should be able to just eliminate such GetLocals, when we know
+                    // what their incoming value will be.
+                    // https://bugs.webkit.org/show_bug.cgi?id=141624
+                    if (node->op() == GetStack) {
+                        StackAccessData* data = node->stackAccessData();
+                        VirtualRegister operand = data->local;
+                        mapping.operand(operand) = node;
+                    }
                     break;
                 } }