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<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/187354">187354</a></dd>
<dt>Author</dt> <dd>basile_clement@apple.com</dd>
<dt>Date</dt> <dd>2015-07-24 11:56:48 -0700 (Fri, 24 Jul 2015)</dd>
</dl>
<h3>Log Message</h3>
<pre>jsc-tailcall: Repatching tail calls as jump should depend on the opcode, not the JS CallLinkInfo
https://bugs.webkit.org/show_bug.cgi?id=147243
Reviewed by Michael Saboff.
When linking, we are currently looking at data from the JS CallLinkInfo
to determine if we have a call or jump opcode. However, even with a
tail call, the slow path uses a call opcode for simplicity.
This adds the information that we are performing a tail call into the
CodeLocationNearCall class, which allows us to link as jump or call
based on the actual opcode.
This is a conceptual error that couldn't be found on X86 architecture
since the patching of jump and calls is identical there.
* assembler/AbstractMacroAssembler.h:
(JSC::AbstractMacroAssembler::repatchNearCall):
* assembler/CodeLocation.h:
(JSC::CodeLocationNearCall::CodeLocationNearCall):
(JSC::CodeLocationNearCall::isTail):
(JSC::CodeLocationCommon::nearCallAtOffset):
* assembler/LinkBuffer.h:
(JSC::LinkBuffer::locationOfNearCall):
* assembler/RepatchBuffer.h:
(JSC::RepatchBuffer::relink):
* jit/Repatch.cpp:
(JSC::linkSlowFor):
(JSC::linkFor):
(JSC::revertCall):
(JSC::linkPolymorphicCall):</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#branchesjsctailcallSourceJavaScriptCoreChangeLog">branches/jsc-tailcall/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#branchesjsctailcallSourceJavaScriptCoreassemblerAbstractMacroAssemblerh">branches/jsc-tailcall/Source/JavaScriptCore/assembler/AbstractMacroAssembler.h</a></li>
<li><a href="#branchesjsctailcallSourceJavaScriptCoreassemblerCodeLocationh">branches/jsc-tailcall/Source/JavaScriptCore/assembler/CodeLocation.h</a></li>
<li><a href="#branchesjsctailcallSourceJavaScriptCoreassemblerLinkBufferh">branches/jsc-tailcall/Source/JavaScriptCore/assembler/LinkBuffer.h</a></li>
<li><a href="#branchesjsctailcallSourceJavaScriptCoreassemblerRepatchBufferh">branches/jsc-tailcall/Source/JavaScriptCore/assembler/RepatchBuffer.h</a></li>
<li><a href="#branchesjsctailcallSourceJavaScriptCorejitRepatchcpp">branches/jsc-tailcall/Source/JavaScriptCore/jit/Repatch.cpp</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="branchesjsctailcallSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: branches/jsc-tailcall/Source/JavaScriptCore/ChangeLog (187353 => 187354)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsc-tailcall/Source/JavaScriptCore/ChangeLog 2015-07-24 18:51:48 UTC (rev 187353)
+++ branches/jsc-tailcall/Source/JavaScriptCore/ChangeLog 2015-07-24 18:56:48 UTC (rev 187354)
</span><span class="lines">@@ -1,3 +1,37 @@
</span><ins>+2015-07-23 Basile Clement <basile_clement@apple.com>
+
+ jsc-tailcall: Repatching tail calls as jump should depend on the opcode, not the JS CallLinkInfo
+ https://bugs.webkit.org/show_bug.cgi?id=147243
+
+ Reviewed by Michael Saboff.
+
+ When linking, we are currently looking at data from the JS CallLinkInfo
+ to determine if we have a call or jump opcode. However, even with a
+ tail call, the slow path uses a call opcode for simplicity.
+
+ This adds the information that we are performing a tail call into the
+ CodeLocationNearCall class, which allows us to link as jump or call
+ based on the actual opcode.
+
+ This is a conceptual error that couldn't be found on X86 architecture
+ since the patching of jump and calls is identical there.
+
+ * assembler/AbstractMacroAssembler.h:
+ (JSC::AbstractMacroAssembler::repatchNearCall):
+ * assembler/CodeLocation.h:
+ (JSC::CodeLocationNearCall::CodeLocationNearCall):
+ (JSC::CodeLocationNearCall::isTail):
+ (JSC::CodeLocationCommon::nearCallAtOffset):
+ * assembler/LinkBuffer.h:
+ (JSC::LinkBuffer::locationOfNearCall):
+ * assembler/RepatchBuffer.h:
+ (JSC::RepatchBuffer::relink):
+ * jit/Repatch.cpp:
+ (JSC::linkSlowFor):
+ (JSC::linkFor):
+ (JSC::revertCall):
+ (JSC::linkPolymorphicCall):
+
</ins><span class="cx"> 2015-07-21 Basile Clement <basile_clement@apple.com>
</span><span class="cx">
</span><span class="cx"> jsc-tailcall: Add new opcodes for tail calls
</span></span></pre></div>
<a id="branchesjsctailcallSourceJavaScriptCoreassemblerAbstractMacroAssemblerh"></a>
<div class="modfile"><h4>Modified: branches/jsc-tailcall/Source/JavaScriptCore/assembler/AbstractMacroAssembler.h (187353 => 187354)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsc-tailcall/Source/JavaScriptCore/assembler/AbstractMacroAssembler.h 2015-07-24 18:51:48 UTC (rev 187353)
+++ branches/jsc-tailcall/Source/JavaScriptCore/assembler/AbstractMacroAssembler.h 2015-07-24 18:56:48 UTC (rev 187354)
</span><span class="lines">@@ -1153,7 +1153,15 @@
</span><span class="cx">
</span><span class="cx"> static void repatchNearCall(CodeLocationNearCall nearCall, CodeLocationLabel destination)
</span><span class="cx"> {
</span><del>- AssemblerType::relinkCall(nearCall.dataLocation(), destination.executableAddress());
</del><ins>+ switch (nearCall.callMode()) {
+ case CallMode::Tail:
+ AssemblerType::relinkJump(nearCall.dataLocation(), destination.executableAddress());
+ return;
+ case CallMode::Regular:
+ AssemblerType::relinkCall(nearCall.dataLocation(), destination.executableAddress());
+ return;
+ }
+ RELEASE_ASSERT_NOT_REACHED();
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> static void repatchCompact(CodeLocationDataLabelCompact dataLabelCompact, int32_t value)
</span></span></pre></div>
<a id="branchesjsctailcallSourceJavaScriptCoreassemblerCodeLocationh"></a>
<div class="modfile"><h4>Modified: branches/jsc-tailcall/Source/JavaScriptCore/assembler/CodeLocation.h (187353 => 187354)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsc-tailcall/Source/JavaScriptCore/assembler/CodeLocation.h 2015-07-24 18:51:48 UTC (rev 187353)
+++ branches/jsc-tailcall/Source/JavaScriptCore/assembler/CodeLocation.h 2015-07-24 18:56:48 UTC (rev 187354)
</span><span class="lines">@@ -32,6 +32,8 @@
</span><span class="cx">
</span><span class="cx"> namespace JSC {
</span><span class="cx">
</span><ins>+enum CallMode { Regular, Tail };
+
</ins><span class="cx"> class CodeLocationInstruction;
</span><span class="cx"> class CodeLocationLabel;
</span><span class="cx"> class CodeLocationJump;
</span><span class="lines">@@ -59,7 +61,7 @@
</span><span class="cx"> CodeLocationLabel labelAtOffset(int offset);
</span><span class="cx"> CodeLocationJump jumpAtOffset(int offset);
</span><span class="cx"> CodeLocationCall callAtOffset(int offset);
</span><del>- CodeLocationNearCall nearCallAtOffset(int offset);
</del><ins>+ CodeLocationNearCall nearCallAtOffset(int offset, CallMode);
</ins><span class="cx"> CodeLocationDataLabelPtr dataLabelPtrAtOffset(int offset);
</span><span class="cx"> CodeLocationDataLabel32 dataLabel32AtOffset(int offset);
</span><span class="cx"> CodeLocationDataLabelCompact dataLabelCompactAtOffset(int offset);
</span><span class="lines">@@ -115,10 +117,13 @@
</span><span class="cx"> class CodeLocationNearCall : public CodeLocationCommon {
</span><span class="cx"> public:
</span><span class="cx"> CodeLocationNearCall() {}
</span><del>- explicit CodeLocationNearCall(MacroAssemblerCodePtr location)
- : CodeLocationCommon(location) {}
- explicit CodeLocationNearCall(void* location)
- : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
</del><ins>+ explicit CodeLocationNearCall(MacroAssemblerCodePtr location, CallMode callMode)
+ : CodeLocationCommon(location), m_callMode(callMode) {}
+ explicit CodeLocationNearCall(void* location, CallMode callMode)
+ : CodeLocationCommon(MacroAssemblerCodePtr(location)), m_callMode(callMode) {}
+ CallMode callMode() { return m_callMode; }
+private:
+ CallMode m_callMode = CallMode::Regular;
</ins><span class="cx"> };
</span><span class="cx">
</span><span class="cx"> class CodeLocationDataLabel32 : public CodeLocationCommon {
</span><span class="lines">@@ -181,10 +186,10 @@
</span><span class="cx"> return CodeLocationCall(reinterpret_cast<char*>(dataLocation()) + offset);
</span><span class="cx"> }
</span><span class="cx">
</span><del>-inline CodeLocationNearCall CodeLocationCommon::nearCallAtOffset(int offset)
</del><ins>+inline CodeLocationNearCall CodeLocationCommon::nearCallAtOffset(int offset, CallMode callMode)
</ins><span class="cx"> {
</span><span class="cx"> ASSERT_VALID_CODE_OFFSET(offset);
</span><del>- return CodeLocationNearCall(reinterpret_cast<char*>(dataLocation()) + offset);
</del><ins>+ return CodeLocationNearCall(reinterpret_cast<char*>(dataLocation()) + offset, callMode);
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> inline CodeLocationDataLabelPtr CodeLocationCommon::dataLabelPtrAtOffset(int offset)
</span></span></pre></div>
<a id="branchesjsctailcallSourceJavaScriptCoreassemblerLinkBufferh"></a>
<div class="modfile"><h4>Modified: branches/jsc-tailcall/Source/JavaScriptCore/assembler/LinkBuffer.h (187353 => 187354)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsc-tailcall/Source/JavaScriptCore/assembler/LinkBuffer.h 2015-07-24 18:51:48 UTC (rev 187353)
+++ branches/jsc-tailcall/Source/JavaScriptCore/assembler/LinkBuffer.h 2015-07-24 18:56:48 UTC (rev 187354)
</span><span class="lines">@@ -180,7 +180,8 @@
</span><span class="cx"> {
</span><span class="cx"> ASSERT(call.isFlagSet(Call::Linkable));
</span><span class="cx"> ASSERT(call.isFlagSet(Call::Near));
</span><del>- return CodeLocationNearCall(MacroAssembler::getLinkerAddress(code(), applyOffset(call.m_label)));
</del><ins>+ return CodeLocationNearCall(MacroAssembler::getLinkerAddress(code(), applyOffset(call.m_label)),
+ call.isFlagSet(Call::Tail) ? CallMode::Tail : CallMode::Regular);
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> CodeLocationLabel locationOf(PatchableJump jump)
</span></span></pre></div>
<a id="branchesjsctailcallSourceJavaScriptCoreassemblerRepatchBufferh"></a>
<div class="modfile"><h4>Modified: branches/jsc-tailcall/Source/JavaScriptCore/assembler/RepatchBuffer.h (187353 => 187354)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsc-tailcall/Source/JavaScriptCore/assembler/RepatchBuffer.h 2015-07-24 18:51:48 UTC (rev 187353)
+++ branches/jsc-tailcall/Source/JavaScriptCore/assembler/RepatchBuffer.h 2015-07-24 18:56:48 UTC (rev 187354)
</span><span class="lines">@@ -80,17 +80,14 @@
</span><span class="cx"> MacroAssembler::repatchCall(call, destination);
</span><span class="cx"> }
</span><span class="cx">
</span><del>- void relink(CodeLocationNearCall nearCall, CodePtr destination, CallLinkInfo::CallType callType)
</del><ins>+ void relink(CodeLocationNearCall nearCall, CodePtr destination)
</ins><span class="cx"> {
</span><del>- relink(nearCall, CodeLocationLabel(destination), callType);
</del><ins>+ relink(nearCall, CodeLocationLabel(destination));
</ins><span class="cx"> }
</span><span class="cx">
</span><del>- void relink(CodeLocationNearCall nearCall, CodeLocationLabel destination, CallLinkInfo::CallType callType)
</del><ins>+ void relink(CodeLocationNearCall nearCall, CodeLocationLabel destination)
</ins><span class="cx"> {
</span><del>- if (CallLinkInfo::isTailCallType(callType))
- MacroAssembler::repatchJump(CodeLocationJump(nearCall.dataLocation()), destination);
- else
- MacroAssembler::repatchNearCall(nearCall, destination);
</del><ins>+ MacroAssembler::repatchNearCall(nearCall, destination);
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> void repatch(CodeLocationDataLabel32 dataLabel32, int32_t value)
</span></span></pre></div>
<a id="branchesjsctailcallSourceJavaScriptCorejitRepatchcpp"></a>
<div class="modfile"><h4>Modified: branches/jsc-tailcall/Source/JavaScriptCore/jit/Repatch.cpp (187353 => 187354)</h4>
<pre class="diff"><span>
<span class="info">--- branches/jsc-tailcall/Source/JavaScriptCore/jit/Repatch.cpp 2015-07-24 18:51:48 UTC (rev 187353)
+++ branches/jsc-tailcall/Source/JavaScriptCore/jit/Repatch.cpp 2015-07-24 18:56:48 UTC (rev 187354)
</span><span class="lines">@@ -1606,8 +1606,7 @@
</span><span class="cx"> {
</span><span class="cx"> repatchBuffer.relink(
</span><span class="cx"> callLinkInfo.callReturnLocation(),
</span><del>- virtualThunk(vm, callLinkInfo, kind, registers).code(),
- callLinkInfo.callType());
</del><ins>+ virtualThunk(vm, callLinkInfo, kind, registers).code());
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> void linkFor(
</span><span class="lines">@@ -1628,7 +1627,7 @@
</span><span class="cx"> callLinkInfo.setLastSeenCallee(exec->callerFrame()->vm(), callerCodeBlock->ownerExecutable(), callee);
</span><span class="cx"> if (shouldShowDisassemblyFor(callerCodeBlock))
</span><span class="cx"> dataLog("Linking call in ", *callerCodeBlock, " at ", callLinkInfo.codeOrigin(), " to ", pointerDump(calleeCodeBlock), ", entrypoint at ", codePtr, "\n");
</span><del>- repatchBuffer.relink(callLinkInfo.hotPathOther(), codePtr, callLinkInfo.callType());
</del><ins>+ repatchBuffer.relink(callLinkInfo.hotPathOther(), codePtr);
</ins><span class="cx">
</span><span class="cx"> if (calleeCodeBlock)
</span><span class="cx"> calleeCodeBlock->linkIncomingCall(exec->callerFrame(), &callLinkInfo);
</span><span class="lines">@@ -1636,8 +1635,7 @@
</span><span class="cx"> if (kind == CodeForCall) {
</span><span class="cx"> repatchBuffer.relink(
</span><span class="cx"> callLinkInfo.callReturnLocation(),
</span><del>- linkPolymorphicCallThunk(vm, callLinkInfo, registers).code(),
- callLinkInfo.callType());
</del><ins>+ linkPolymorphicCallThunk(vm, callLinkInfo, registers).code());
</ins><span class="cx"> return;
</span><span class="cx"> }
</span><span class="cx">
</span><span class="lines">@@ -1665,7 +1663,7 @@
</span><span class="cx"> RepatchBuffer::startOfBranchPtrWithPatchOnRegister(callLinkInfo.hotPathBegin()),
</span><span class="cx"> static_cast<MacroAssembler::RegisterID>(callLinkInfo.calleeGPR()), 0);
</span><span class="cx"> repatchBuffer.relink(
</span><del>- callLinkInfo.callReturnLocation(), codeRef.code(), callLinkInfo.callType());
</del><ins>+ callLinkInfo.callReturnLocation(), codeRef.code());
</ins><span class="cx"> callLinkInfo.clearSeen();
</span><span class="cx"> callLinkInfo.clearCallee();
</span><span class="cx"> callLinkInfo.clearStub();
</span><span class="lines">@@ -1944,8 +1942,7 @@
</span><span class="cx"> // taking the polymorphic path on 32 bit platforms
</span><span class="cx"> repatchBuffer.relink(
</span><span class="cx"> callLinkInfo.callReturnLocation(),
</span><del>- slowPathCodePtr,
- callLinkInfo.callType());
</del><ins>+ slowPathCodePtr);
</ins><span class="cx">
</span><span class="cx"> // If there had been a previous stub routine, that one will die as soon as the GC runs and sees
</span><span class="cx"> // that it's no longer on stack.
</span></span></pre>
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