Changeset 92071 in webkit

Timestamp:

Jul 30, 2011 11:14:10 PM (13 years ago)

Author:

fpizlo@apple.com

Message:

DFG JIT speculation failure pass sometimes forgets to emit code to
move certain registers.
​https://bugs.webkit.org/show_bug.cgi?id=65421

Reviewed by Oliver Hunt.

Restructured the offending loops (for gprs and fprs). It's once again
possible to use spreadsheets on docs.google.com.

• dfg/DFGJITCompiler.cpp:

(JSC::DFG::JITCompiler::jumpFromSpeculativeToNonSpeculative):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• dfg/DFGJITCompiler.cpp (modified) (4 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2011-07-30  Filip Pizlo  <fpizlo@apple.com>
+
+        DFG JIT speculation failure pass sometimes forgets to emit code to
+        move certain registers.
+        https://bugs.webkit.org/show_bug.cgi?id=65421
+
+        Reviewed by Oliver Hunt.
+        
+        Restructured the offending loops (for gprs and fprs).  It's once again
+        possible to use spreadsheets on docs.google.com.
+
+        * dfg/DFGJITCompiler.cpp:
+        (JSC::DFG::JITCompiler::jumpFromSpeculativeToNonSpeculative):
+
 2011-07-30  Patrick Gansterer  <paroga@webkit.org>
 

trunk/Source/JavaScriptCore/dfg/DFGJITCompiler.cpp

@@ -567 +567 @@
     for (unsigned index = 0; index < GPRInfo::numberOfRegisters; ++index) {
         NodeIndex nodeIndex = check.m_gprInfo[index].nodeIndex;
-        if (nodeIndex == NoNode || check.m_gprInfo[index].isSpilled) {
+        
+        // Bail out if this register isn't assigned to anything.
+        if (nodeIndex == NoNode) {
             scratchGPR = GPRInfo::toRegister(index);
             continue;
         }
         
+        // If the non-speculative path also has a register for the nodeIndex that this
+        // register stores, link them together.
         NodeToRegisterMap::iterator mapIterator = entryNodeToRegisterMap.find(nodeIndex);
         if (mapIterator != entryNodeToRegisterMap.end()) {
@@ -580 +584 @@
             next->hasTo = true;
             
+            // If the non-speculative path has not spilled this register, then skip the spillin
+            // part below regardless of whether or not the speculative path has spilled it.
             if (!mapIterator->second.findInEntryLocation(entry).isSpilled)
                 continue;
         }
         
+        // If the speculative path has already spilled the register then there is no need to
+        // spill it.
+        if (check.m_gprInfo[index].isSpilled)
+            continue;
+        
         DataFormat dataFormat = check.m_gprInfo[index].format;
         VirtualRegister virtualRegister = graph()[nodeIndex].virtualRegister();
-
+        
         ASSERT(dataFormat == DataFormatInteger || DataFormatCell || dataFormat & DataFormatJS);
         if (dataFormat == DataFormatInteger)
@@ -602 +613 @@
     for (unsigned index = 0; index < FPRInfo::numberOfRegisters; ++index) {
         NodeIndex nodeIndex = check.m_fprInfo[index].nodeIndex;
-        if (nodeIndex == NoNode || check.m_fprInfo[index].isSpilled)
+        if (nodeIndex == NoNode)
             continue;
 
@@ -616 +627 @@
                 continue;
         }
+        
+        if (check.m_fprInfo[index].isSpilled)
+            continue;
 
         VirtualRegister virtualRegister = graph()[nodeIndex].virtualRegister();