Changeset 213856 in webkit

Timestamp:

Mar 13, 2017 11:00:25 AM (7 years ago)

Author:

fpizlo@apple.com

Message:

FTL should not flush strict arguments unless it really needs to
​https://bugs.webkit.org/show_bug.cgi?id=169519

Reviewed by Mark Lam.

JSTests:

This benchmark runs 3.5x faster thanks to this patch.

• microbenchmarks/strict-arguments-no-escape.js: Added.

(foo):
(bar):
(baz):

Source/JavaScriptCore:

This is a refinement that we should have done ages ago. This kills some pointless PutStacks
in DFG SSA IR. It can sometimes unlock other optimizations.

• dfg/DFGPreciseLocalClobberize.h:

(JSC::DFG::PreciseLocalClobberizeAdaptor::readTop):

Location:

trunk

Files:

• JSTests/ChangeLog (modified) (1 diff)
• JSTests/microbenchmarks/strict-arguments-no-escape.js (added)
• Source/JavaScriptCore/ChangeLog (modified) (1 diff)
• Source/JavaScriptCore/dfg/DFGPreciseLocalClobberize.h (modified) (2 diffs)

trunk/JSTests/ChangeLog

@@ +1 @@
+2017-03-11  Filip Pizlo  <fpizlo@apple.com>
+
+        FTL should not flush strict arguments unless it really needs to
+        https://bugs.webkit.org/show_bug.cgi?id=169519
+
+        Reviewed by Mark Lam.
+        
+        This benchmark runs 3.5x faster thanks to this patch.
+
+        * microbenchmarks/strict-arguments-no-escape.js: Added.
+        (foo):
+        (bar):
+        (baz):
+
 2017-03-13  Caio Lima  <ticaiolima@gmail.com>
 

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2017-03-11  Filip Pizlo  <fpizlo@apple.com>
+
+        FTL should not flush strict arguments unless it really needs to
+        https://bugs.webkit.org/show_bug.cgi?id=169519
+
+        Reviewed by Mark Lam.
+        
+        This is a refinement that we should have done ages ago. This kills some pointless PutStacks
+        in DFG SSA IR. It can sometimes unlock other optimizations.
+
+        * dfg/DFGPreciseLocalClobberize.h:
+        (JSC::DFG::PreciseLocalClobberizeAdaptor::readTop):
+
 2017-03-13  Caio Lima  <ticaiolima@gmail.com>
 

trunk/Source/JavaScriptCore/dfg/DFGPreciseLocalClobberize.h

@@ -198 +198 @@
             
         default: {
-            // All of the outermost arguments, except this, are definitely read.
-            for (unsigned i = m_graph.m_codeBlock->numParameters(); i-- > 1;)
-                m_read(virtualRegisterForArgument(i));
+            // All of the outermost arguments, except this, are read in sloppy mode.
+            if (!m_graph.m_codeBlock->isStrictMode()) {
+                for (unsigned i = m_graph.m_codeBlock->numParameters(); i-- > 1;)
+                    m_read(virtualRegisterForArgument(i));
+            }
         
             // The stack header is read.
@@ -208 +210 @@
             // Read all of the inline arguments and call frame headers that we didn't already capture.
             for (InlineCallFrame* inlineCallFrame = m_node->origin.semantic.inlineCallFrame; inlineCallFrame; inlineCallFrame = inlineCallFrame->getCallerInlineFrameSkippingTailCalls()) {
-                for (unsigned i = inlineCallFrame->arguments.size(); i-- > 1;)
-                    m_read(VirtualRegister(inlineCallFrame->stackOffset + virtualRegisterForArgument(i).offset()));
+                if (!inlineCallFrame->isStrictMode()) {
+                    for (unsigned i = inlineCallFrame->arguments.size(); i-- > 1;)
+                        m_read(VirtualRegister(inlineCallFrame->stackOffset + virtualRegisterForArgument(i).offset()));
+                }
                 if (inlineCallFrame->isClosureCall)
                     m_read(VirtualRegister(inlineCallFrame->stackOffset + CallFrameSlot::callee));