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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/199792">199792</a></dd>
<dt>Author</dt> <dd>commit-queue@webkit.org</dd>
<dt>Date</dt> <dd>2016-04-20 15:24:32 -0700 (Wed, 20 Apr 2016)</dd>
</dl>
<h3>Log Message</h3>
<pre>[JSC] Add register reuse for ArithAdd of an Int32 and constant in DFG
https://bugs.webkit.org/show_bug.cgi?id=155164
Patch by Benjamin Poulain <bpoulain@apple.com> on 2016-04-20
Reviewed by Mark Lam.
Every "inc" in loop was looking like this:
move rX, rY
inc rY
jo 0x230f4a200580
This patch add register Reuse to that case to remove
the extra "move".
* dfg/DFGOSRExit.h:
(JSC::DFG::SpeculationRecovery::SpeculationRecovery):
(JSC::DFG::SpeculationRecovery::immediate):
* dfg/DFGOSRExitCompiler32_64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* dfg/DFGOSRExitCompiler64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::compileArithAdd):
* tests/stress/arith-add-with-constant-overflow.js: Added.
(opaqueAdd):</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceJavaScriptCoreChangeLog">trunk/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoreassemblerMacroAssemblerh">trunk/Source/JavaScriptCore/assembler/MacroAssembler.h</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGOSRExith">trunk/Source/JavaScriptCore/dfg/DFGOSRExit.h</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGOSRExitCompiler32_64cpp">trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler32_64.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGOSRExitCompiler64cpp">trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler64.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGSpeculativeJITcpp">trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp</a></li>
</ul>
<h3>Added Paths</h3>
<ul>
<li><a href="#trunkSourceJavaScriptCoretestsstressarithaddwithconstantoverflowjs">trunk/Source/JavaScriptCore/tests/stress/arith-add-with-constant-overflow.js</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/ChangeLog (199791 => 199792)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/ChangeLog 2016-04-20 22:03:09 UTC (rev 199791)
+++ trunk/Source/JavaScriptCore/ChangeLog 2016-04-20 22:24:32 UTC (rev 199792)
</span><span class="lines">@@ -1,3 +1,30 @@
</span><ins>+2016-04-20 Benjamin Poulain <bpoulain@apple.com>
+
+ [JSC] Add register reuse for ArithAdd of an Int32 and constant in DFG
+ https://bugs.webkit.org/show_bug.cgi?id=155164
+
+ Reviewed by Mark Lam.
+
+ Every "inc" in loop was looking like this:
+ move rX, rY
+ inc rY
+ jo 0x230f4a200580
+
+ This patch add register Reuse to that case to remove
+ the extra "move".
+
+ * dfg/DFGOSRExit.h:
+ (JSC::DFG::SpeculationRecovery::SpeculationRecovery):
+ (JSC::DFG::SpeculationRecovery::immediate):
+ * dfg/DFGOSRExitCompiler32_64.cpp:
+ (JSC::DFG::OSRExitCompiler::compileExit):
+ * dfg/DFGOSRExitCompiler64.cpp:
+ (JSC::DFG::OSRExitCompiler::compileExit):
+ * dfg/DFGSpeculativeJIT.cpp:
+ (JSC::DFG::SpeculativeJIT::compileArithAdd):
+ * tests/stress/arith-add-with-constant-overflow.js: Added.
+ (opaqueAdd):
+
</ins><span class="cx"> 2016-04-20 Saam barati <sbarati@apple.com>
</span><span class="cx">
</span><span class="cx"> We don't need a manual stack for an RAII object when the machine's stack will do just fine
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreassemblerMacroAssemblerh"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/assembler/MacroAssembler.h (199791 => 199792)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/assembler/MacroAssembler.h 2016-04-20 22:03:09 UTC (rev 199791)
+++ trunk/Source/JavaScriptCore/assembler/MacroAssembler.h 2016-04-20 22:24:32 UTC (rev 199792)
</span><span class="lines">@@ -1694,16 +1694,20 @@
</span><span class="cx">
</span><span class="cx"> Jump branchAdd32(ResultCondition cond, RegisterID src, Imm32 imm, RegisterID dest)
</span><span class="cx"> {
</span><del>- if (src == dest)
- ASSERT(haveScratchRegisterForBlinding());
-
</del><span class="cx"> if (shouldBlind(imm)) {
</span><del>- if (src == dest) {
- move(src, scratchRegisterForBlinding());
- src = scratchRegisterForBlinding();
</del><ins>+ if (src != dest || haveScratchRegisterForBlinding()) {
+ if (src == dest) {
+ move(src, scratchRegisterForBlinding());
+ src = scratchRegisterForBlinding();
+ }
+ loadXorBlindedConstant(xorBlindConstant(imm), dest);
+ return branchAdd32(cond, src, dest);
</ins><span class="cx"> }
</span><del>- loadXorBlindedConstant(xorBlindConstant(imm), dest);
- return branchAdd32(cond, src, dest);
</del><ins>+ // If we don't have a scratch register available for use, we'll just
+ // place a random number of nops.
+ uint32_t nopCount = random() & 3;
+ while (nopCount--)
+ nop();
</ins><span class="cx"> }
</span><span class="cx"> return branchAdd32(cond, src, imm.asTrustedImm32(), dest);
</span><span class="cx"> }
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGOSRExith"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGOSRExit.h (199791 => 199792)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGOSRExit.h 2016-04-20 22:03:09 UTC (rev 199791)
+++ trunk/Source/JavaScriptCore/dfg/DFGOSRExit.h 2016-04-20 22:24:32 UTC (rev 199792)
</span><span class="lines">@@ -48,8 +48,9 @@
</span><span class="cx">
</span><span class="cx"> // This enum describes the types of additional recovery that
</span><span class="cx"> // may need be performed should a speculation check fail.
</span><del>-enum SpeculationRecoveryType {
</del><ins>+enum SpeculationRecoveryType : uint8_t {
</ins><span class="cx"> SpeculativeAdd,
</span><ins>+ SpeculativeAddImmediate,
</ins><span class="cx"> BooleanSpeculationCheck
</span><span class="cx"> };
</span><span class="cx">
</span><span class="lines">@@ -60,22 +61,36 @@
</span><span class="cx"> class SpeculationRecovery {
</span><span class="cx"> public:
</span><span class="cx"> SpeculationRecovery(SpeculationRecoveryType type, GPRReg dest, GPRReg src)
</span><del>- : m_type(type)
</del><ins>+ : m_src(src)
</ins><span class="cx"> , m_dest(dest)
</span><del>- , m_src(src)
</del><ins>+ , m_type(type)
</ins><span class="cx"> {
</span><ins>+ ASSERT(m_type == SpeculativeAdd || m_type == BooleanSpeculationCheck);
</ins><span class="cx"> }
</span><span class="cx">
</span><ins>+ SpeculationRecovery(SpeculationRecoveryType type, GPRReg dest, int32_t immediate)
+ : m_immediate(immediate)
+ , m_dest(dest)
+ , m_type(type)
+ {
+ ASSERT(m_type == SpeculativeAddImmediate);
+ }
+
</ins><span class="cx"> SpeculationRecoveryType type() { return m_type; }
</span><span class="cx"> GPRReg dest() { return m_dest; }
</span><span class="cx"> GPRReg src() { return m_src; }
</span><ins>+ int32_t immediate() { return m_immediate; }
</ins><span class="cx">
</span><span class="cx"> private:
</span><ins>+ // different recovery types may required different additional information here.
+ union {
+ GPRReg m_src;
+ int32_t m_immediate;
+ };
+ GPRReg m_dest;
+
</ins><span class="cx"> // Indicates the type of additional recovery to be performed.
</span><span class="cx"> SpeculationRecoveryType m_type;
</span><del>- // different recovery types may required different additional information here.
- GPRReg m_dest;
- GPRReg m_src;
</del><span class="cx"> };
</span><span class="cx">
</span><span class="cx"> // === OSRExit ===
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGOSRExitCompiler32_64cpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler32_64.cpp (199791 => 199792)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler32_64.cpp 2016-04-20 22:03:09 UTC (rev 199791)
+++ trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler32_64.cpp 2016-04-20 22:24:32 UTC (rev 199792)
</span><span class="lines">@@ -56,6 +56,10 @@
</span><span class="cx"> case SpeculativeAdd:
</span><span class="cx"> m_jit.sub32(recovery->src(), recovery->dest());
</span><span class="cx"> break;
</span><ins>+
+ case SpeculativeAddImmediate:
+ m_jit.sub32(AssemblyHelpers::Imm32(recovery->immediate()), recovery->dest());
+ break;
</ins><span class="cx">
</span><span class="cx"> case BooleanSpeculationCheck:
</span><span class="cx"> break;
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGOSRExitCompiler64cpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler64.cpp (199791 => 199792)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler64.cpp 2016-04-20 22:03:09 UTC (rev 199791)
+++ trunk/Source/JavaScriptCore/dfg/DFGOSRExitCompiler64.cpp 2016-04-20 22:24:32 UTC (rev 199792)
</span><span class="lines">@@ -61,6 +61,11 @@
</span><span class="cx"> m_jit.sub32(recovery->src(), recovery->dest());
</span><span class="cx"> m_jit.or64(GPRInfo::tagTypeNumberRegister, recovery->dest());
</span><span class="cx"> break;
</span><ins>+
+ case SpeculativeAddImmediate:
+ m_jit.sub32(AssemblyHelpers::Imm32(recovery->immediate()), recovery->dest());
+ m_jit.or64(GPRInfo::tagTypeNumberRegister, recovery->dest());
+ break;
</ins><span class="cx">
</span><span class="cx"> case BooleanSpeculationCheck:
</span><span class="cx"> m_jit.xor64(AssemblyHelpers::TrustedImm32(static_cast<int32_t>(ValueFalse)), recovery->dest());
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGSpeculativeJITcpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp (199791 => 199792)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp 2016-04-20 22:03:09 UTC (rev 199791)
+++ trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp 2016-04-20 22:24:32 UTC (rev 199792)
</span><span class="lines">@@ -3496,19 +3496,26 @@
</span><span class="cx">
</span><span class="cx"> if (node->child2()->isInt32Constant()) {
</span><span class="cx"> SpeculateInt32Operand op1(this, node->child1());
</span><ins>+ GPRTemporary result(this, Reuse, op1);
+
+ GPRReg gpr1 = op1.gpr();
</ins><span class="cx"> int32_t imm2 = node->child2()->asInt32();
</span><ins>+ GPRReg gprResult = result.gpr();
</ins><span class="cx">
</span><span class="cx"> if (!shouldCheckOverflow(node->arithMode())) {
</span><del>- GPRTemporary result(this, Reuse, op1);
- m_jit.add32(Imm32(imm2), op1.gpr(), result.gpr());
- int32Result(result.gpr(), node);
</del><ins>+ m_jit.add32(Imm32(imm2), gpr1, gprResult);
+ int32Result(gprResult, node);
</ins><span class="cx"> return;
</span><span class="cx"> }
</span><span class="cx">
</span><del>- GPRTemporary result(this);
- speculationCheck(Overflow, JSValueRegs(), 0, m_jit.branchAdd32(MacroAssembler::Overflow, op1.gpr(), Imm32(imm2), result.gpr()));
</del><ins>+ MacroAssembler::Jump check = m_jit.branchAdd32(MacroAssembler::Overflow, gpr1, Imm32(imm2), gprResult);
+ if (gpr1 == gprResult) {
+ speculationCheck(Overflow, JSValueRegs(), 0, check,
+ SpeculationRecovery(SpeculativeAddImmediate, gpr1, imm2));
+ } else
+ speculationCheck(Overflow, JSValueRegs(), 0, check);
</ins><span class="cx">
</span><del>- int32Result(result.gpr(), node);
</del><ins>+ int32Result(gprResult, node);
</ins><span class="cx"> return;
</span><span class="cx"> }
</span><span class="cx">
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoretestsstressarithaddwithconstantoverflowjs"></a>
<div class="addfile"><h4>Added: trunk/Source/JavaScriptCore/tests/stress/arith-add-with-constant-overflow.js (0 => 199792)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/tests/stress/arith-add-with-constant-overflow.js (rev 0)
+++ trunk/Source/JavaScriptCore/tests/stress/arith-add-with-constant-overflow.js 2016-04-20 22:24:32 UTC (rev 199792)
</span><span class="lines">@@ -0,0 +1,21 @@
</span><ins>+function opaqueAdd(a)
+{
+ return a + 42;
+}
+noInline(opaqueAdd);
+
+// Warm up.
+for (let i = 0; i < 1e4; ++i) {
+ let result = opaqueAdd(5);
+ if (result !== 47)
+ throw "Invalid opaqueAdd(5) at i = " + i;
+}
+
+// Overflow.
+for (let i = 0; i < 1e3; ++i) {
+ for (let j = -50; j < 50; ++j) {
+ let result = opaqueAdd(2147483647 + j);
+ if (result !== 2147483689 + j)
+ throw "Invalid opaqueAdd(" + 2147483647 + j + ") at i = " + i + " j = " + j;
+ }
+}
</ins></span></pre>
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