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<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/162666">162666</a></dd>
<dt>Author</dt> <dd>fpizlo@apple.com</dd>
<dt>Date</dt> <dd>2014-01-23 17:18:19 -0800 (Thu, 23 Jan 2014)</dd>
</dl>
<h3>Log Message</h3>
<pre>3x splay regression in FTL with experimental coverage that is entirely due to Bartlett weirdness
https://bugs.webkit.org/show_bug.cgi?id=127463
Reviewed by Mark Hahnenberg.
This turned out to be entirely due to misuse of the scratch buffer in an FTL thunk.
We need to mark a scratch buffer as unused after we're done with it or else the GC
will have a bad time.
But, this also introduces some debugging-related things that were useful on my
journey.
Finally, this turns all experimental FTL coverage into non-experimental coverage for
now. I'm keeping the option because we will probably make other things "experimental"
in the near future, if they cause regressions.
* dfg/DFGTierUpCheckInjectionPhase.cpp:
(JSC::DFG::TierUpCheckInjectionPhase::run): Made it possible to disable FTL OSR entry.
* ftl/FTLCapabilities.cpp:
(JSC::FTL::canCompile): Make the new NodeTypes non-experimental.
* ftl/FTLThunks.cpp:
(JSC::FTL::osrExitGenerationThunkGenerator): Fix the actual bug.
* llint/LowLevelInterpreter.asm:
* runtime/Options.h:
* runtime/VM.cpp:
(JSC::logSanitizeStack):
* runtime/VM.h:
(JSC::sanitizeStackForVM): This is all about making it possible to print things when the stack is sanitized.</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#branchesjsCStackSourceJavaScriptCoreChangeLog">branches/jsCStack/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#branchesjsCStackSourceJavaScriptCoredfgDFGTierUpCheckInjectionPhasecpp">branches/jsCStack/Source/JavaScriptCore/dfg/DFGTierUpCheckInjectionPhase.cpp</a></li>
<li><a href="#branchesjsCStackSourceJavaScriptCoreftlFTLCapabilitiescpp">branches/jsCStack/Source/JavaScriptCore/ftl/FTLCapabilities.cpp</a></li>
<li><a href="#branchesjsCStackSourceJavaScriptCoreftlFTLThunkscpp">branches/jsCStack/Source/JavaScriptCore/ftl/FTLThunks.cpp</a></li>
<li><a href="#branchesjsCStackSourceJavaScriptCorellintLowLevelInterpreterasm">branches/jsCStack/Source/JavaScriptCore/llint/LowLevelInterpreter.asm</a></li>
<li><a href="#branchesjsCStackSourceJavaScriptCoreruntimeOptionsh">branches/jsCStack/Source/JavaScriptCore/runtime/Options.h</a></li>
<li><a href="#branchesjsCStackSourceJavaScriptCoreruntimeVMcpp">branches/jsCStack/Source/JavaScriptCore/runtime/VM.cpp</a></li>
<li><a href="#branchesjsCStackSourceJavaScriptCoreruntimeVMh">branches/jsCStack/Source/JavaScriptCore/runtime/VM.h</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="branchesjsCStackSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/ChangeLog (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/ChangeLog 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/ChangeLog 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -1,3 +1,34 @@
</span><ins>+2014-01-23 Filip Pizlo <fpizlo@apple.com>
+
+ 3x splay regression in FTL with experimental coverage that is entirely due to Bartlett weirdness
+ https://bugs.webkit.org/show_bug.cgi?id=127463
+
+ Reviewed by Mark Hahnenberg.
+
+ This turned out to be entirely due to misuse of the scratch buffer in an FTL thunk.
+ We need to mark a scratch buffer as unused after we're done with it or else the GC
+ will have a bad time.
+
+ But, this also introduces some debugging-related things that were useful on my
+ journey.
+
+ Finally, this turns all experimental FTL coverage into non-experimental coverage for
+ now. I'm keeping the option because we will probably make other things "experimental"
+ in the near future, if they cause regressions.
+
+ * dfg/DFGTierUpCheckInjectionPhase.cpp:
+ (JSC::DFG::TierUpCheckInjectionPhase::run): Made it possible to disable FTL OSR entry.
+ * ftl/FTLCapabilities.cpp:
+ (JSC::FTL::canCompile): Make the new NodeTypes non-experimental.
+ * ftl/FTLThunks.cpp:
+ (JSC::FTL::osrExitGenerationThunkGenerator): Fix the actual bug.
+ * llint/LowLevelInterpreter.asm:
+ * runtime/Options.h:
+ * runtime/VM.cpp:
+ (JSC::logSanitizeStack):
+ * runtime/VM.h:
+ (JSC::sanitizeStackForVM): This is all about making it possible to print things when the stack is sanitized.
+
</ins><span class="cx"> 2014-01-23 Mark Hahnenberg <mhahnenberg@apple.com>
</span><span class="cx">
</span><span class="cx"> Merge branch up to ToT r161658.
</span></span></pre></div>
<a id="branchesjsCStackSourceJavaScriptCoredfgDFGTierUpCheckInjectionPhasecpp"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/dfg/DFGTierUpCheckInjectionPhase.cpp (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/dfg/DFGTierUpCheckInjectionPhase.cpp 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/dfg/DFGTierUpCheckInjectionPhase.cpp 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -58,6 +58,9 @@
</span><span class="cx"> if (level == FTL::CannotCompile)
</span><span class="cx"> return false;
</span><span class="cx">
</span><ins>+ if (!Options::enableOSREntryToFTL())
+ level = FTL::CanCompile;
+
</ins><span class="cx"> InsertionSet insertionSet(m_graph);
</span><span class="cx"> for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
</span><span class="cx"> BasicBlock* block = m_graph.block(blockIndex);
</span></span></pre></div>
<a id="branchesjsCStackSourceJavaScriptCoreftlFTLCapabilitiescpp"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/ftl/FTLCapabilities.cpp (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/ftl/FTLCapabilities.cpp 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/ftl/FTLCapabilities.cpp 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -125,6 +125,11 @@
</span><span class="cx"> case CountExecution:
</span><span class="cx"> case CheckExecutable:
</span><span class="cx"> case GetScope:
</span><ins>+ case AllocationProfileWatchpoint:
+ case CheckArgumentsNotCreated:
+ case GetCallee:
+ case ToString:
+ case MakeRope:
</ins><span class="cx"> // These are OK.
</span><span class="cx"> break;
</span><span class="cx"> case GetById:
</span><span class="lines">@@ -238,14 +243,6 @@
</span><span class="cx"> return CannotCompile;
</span><span class="cx"> }
</span><span class="cx"> break;
</span><del>- case AllocationProfileWatchpoint:
- case CheckArgumentsNotCreated:
- case GetCallee:
- case ToString:
- case MakeRope:
- if (!Options::enableExperimentalFTLCoverage())
- return CannotCompile;
- break;
</del><span class="cx"> default:
</span><span class="cx"> // Don't know how to handle anything else.
</span><span class="cx"> return CannotCompile;
</span></span></pre></div>
<a id="branchesjsCStackSourceJavaScriptCoreftlFTLThunkscpp"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/ftl/FTLThunks.cpp (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/ftl/FTLThunks.cpp 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/ftl/FTLThunks.cpp 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -71,10 +71,13 @@
</span><span class="cx">
</span><span class="cx"> jit.move(GPRInfo::returnValueGPR, GPRInfo::regT0);
</span><span class="cx">
</span><ins>+ // Make sure we tell the GC that we're not using the scratch buffer anymore.
+ jit.move(MacroAssembler::TrustedImmPtr(scratchBuffer->activeLengthPtr()), GPRInfo::regT1);
+ jit.storePtr(MacroAssembler::TrustedImmPtr(0), GPRInfo::regT1);
+
</ins><span class="cx"> // Prepare for tail call.
</span><span class="cx"> jit.pop(GPRInfo::regT1);
</span><span class="cx"> jit.pop(GPRInfo::regT1);
</span><del>- // FIXME: CStack - Need to address the right way to adjust CFR and SP
</del><span class="cx"> jit.pop(MacroAssembler::framePointerRegister);
</span><span class="cx">
</span><span class="cx"> // At this point we're sitting on the return address - so if we did a jump right now, the
</span><span class="lines">@@ -82,7 +85,6 @@
</span><span class="cx"> // restore all registers.
</span><span class="cx">
</span><span class="cx"> jit.restoreReturnAddressBeforeReturn(GPRInfo::regT0);
</span><del>- // FIXME: CStack - Through here
</del><span class="cx">
</span><span class="cx"> restoreAllRegisters(jit, buffer);
</span><span class="cx">
</span></span></pre></div>
<a id="branchesjsCStackSourceJavaScriptCorellintLowLevelInterpreterasm"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/llint/LowLevelInterpreter.asm (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/llint/LowLevelInterpreter.asm 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/llint/LowLevelInterpreter.asm 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -609,8 +609,8 @@
</span><span class="cx">
</span><span class="cx"> if C_LOOP
</span><span class="cx"> else
</span><del>-# void sanitizeStackForVM(VM* vm)
-_sanitizeStackForVM:
</del><ins>+# void sanitizeStackForVMImpl(VM* vm)
+_sanitizeStackForVMImpl:
</ins><span class="cx"> if X86_64
</span><span class="cx"> const vm = t4
</span><span class="cx"> const address = t1
</span></span></pre></div>
<a id="branchesjsCStackSourceJavaScriptCoreruntimeOptionsh"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/runtime/Options.h (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/runtime/Options.h 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/runtime/Options.h 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -129,8 +129,10 @@
</span><span class="cx"> v(bool, verboseFTLFailure, false) \
</span><span class="cx"> v(bool, alwaysComputeHash, false) \
</span><span class="cx"> v(bool, testTheFTL, false) \
</span><ins>+ v(bool, verboseSanitizeStack, false) \
</ins><span class="cx"> \
</span><span class="cx"> v(bool, enableOSREntryToDFG, true) \
</span><ins>+ v(bool, enableOSREntryToFTL, true) \
</ins><span class="cx"> \
</span><span class="cx"> v(bool, useExperimentalFTL, false) \
</span><span class="cx"> v(bool, enableExperimentalFTLCoverage, false) \
</span></span></pre></div>
<a id="branchesjsCStackSourceJavaScriptCoreruntimeVMcpp"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/runtime/VM.cpp (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/runtime/VM.cpp 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/runtime/VM.cpp 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -772,12 +772,17 @@
</span><span class="cx"> }
</span><span class="cx"> #endif
</span><span class="cx">
</span><del>-#if ENABLE(LLINT_C_LOOP)
-void sanitizeStackForVM(VM* vm)
</del><ins>+void logSanitizeStack(VM* vm)
</ins><span class="cx"> {
</span><del>- vm->interpreter->stack().sanitizeStack();
</del><ins>+ if (Options::verboseSanitizeStack() && vm->topCallFrame) {
+ int dummy;
+ dataLog(
+ "Sanitizing stack with top call frame at ", RawPointer(vm->topCallFrame),
+ ", current stack pointer at ", RawPointer(&dummy), ", in ",
+ pointerDump(vm->topCallFrame->codeBlock()), " and last code origin = ",
+ vm->topCallFrame->codeOrigin(), "\n");
+ }
</ins><span class="cx"> }
</span><del>-#endif
</del><span class="cx">
</span><span class="cx"> #if ENABLE(REGEXP_TRACING)
</span><span class="cx"> void VM::addRegExpToTrace(RegExp* regExp)
</span></span></pre></div>
<a id="branchesjsCStackSourceJavaScriptCoreruntimeVMh"></a>
<div class="modfile"><h4>Modified: branches/jsCStack/Source/JavaScriptCore/runtime/VM.h (162665 => 162666)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsCStack/Source/JavaScriptCore/runtime/VM.h 2014-01-24 01:15:11 UTC (rev 162665)
+++ branches/jsCStack/Source/JavaScriptCore/runtime/VM.h 2014-01-24 01:18:19 UTC (rev 162666)
</span><span class="lines">@@ -558,13 +558,21 @@
</span><span class="cx"> return &m_vm->heap;
</span><span class="cx"> }
</span><span class="cx">
</span><del>-#if ENABLE(LLINT)
</del><ins>+#if !ENABLE(LLINT_C_LOOP)
+ extern "C" void sanitizeStackForVMImpl(VM*);
+#endif
+
+ void logSanitizeStack(VM*);
+
+ ALWAYS_INLINE void sanitizeStackForVM(VM* vm)
+ {
+ logSanitizeStack(vm);
</ins><span class="cx"> #if ENABLE(LLINT_C_LOOP)
</span><del>- void sanitizeStackForVM(VM*);
</del><ins>+ vm->interpreter->stack().sanitizeStack();
</ins><span class="cx"> #else
</span><del>- extern "C" void sanitizeStackForVM(VM*);
</del><ins>+ sanitizeStackForVMImpl(vm);
</ins><span class="cx"> #endif
</span><del>-#endif
</del><ins>+ }
</ins><span class="cx">
</span><span class="cx"> } // namespace JSC
</span><span class="cx">
</span></span></pre>
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