DFG optimizes out strict mode arguments tear off

https://bugs.webkit.org/show_bug.cgi?id=119504

Source/JavaScriptCore:

Reviewed by Mark Hahnenberg and Oliver Hunt.

Don't do the optimization for strict mode.

* dfg/DFGArgumentsSimplificationPhase.cpp:
(JSC::DFG::ArgumentsSimplificationPhase::run):
(JSC::DFG::ArgumentsSimplificationPhase::pruneObviousArgumentCreations):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154217 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Change-Id: I68037df21deaa964ff18c4f168f465c2600627f7
Reviewed-by: Julien Brianceau <jbriance@cisco.com>
Reviewed-by: Michael Brüning <michael.bruning@theqtcompany.com>

1 files changed, 11 insertions, 6 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGArgumentsSimplificationPhase.cpp b/Source/JavaScriptCore/dfg/DFGArgumentsSimplificationPhase.cpp
index cbab4e8c8..ec7515eec 100644
--- a/Source/JavaScriptCore/dfg/DFGArgumentsSimplificationPhase.cpp
+++ b/Source/JavaScriptCore/dfg/DFGArgumentsSimplificationPhase.cpp
@@ -123,12 +123,9 @@ public:
         bool changed = false;
         
         // Record which arguments are known to escape no matter what.
-        for (unsigned i = codeBlock()->inlineCallFrames().size(); i--;) {
-            InlineCallFrame* inlineCallFrame = &codeBlock()->inlineCallFrames()[i];
-            if (m_graph.m_executablesWhoseArgumentsEscaped.contains(
-                    m_graph.executableFor(inlineCallFrame)))
-                m_createsArguments.add(inlineCallFrame);
-        }
+        for (unsigned i = codeBlock()->inlineCallFrames().size(); i--;)
+            pruneObviousArgumentCreations(&codeBlock()->inlineCallFrames()[i]);
+        pruneObviousArgumentCreations(0); // the machine call frame.
         
         // Create data for variable access datas that we will want to analyze.
         for (unsigned i = m_graph.m_variableAccessData.size(); i--;) {
@@ -700,6 +697,14 @@ private:
             NullableHashTraits<VariableAccessData*> > m_argumentsAliasing;
     HashSet<VariableAccessData*> m_isLive;
 
+    void pruneObviousArgumentCreations(InlineCallFrame* inlineCallFrame)
+    {
+        ScriptExecutable* executable = jsCast<ScriptExecutable*>(m_graph.executableFor(inlineCallFrame));
+        if (m_graph.m_executablesWhoseArgumentsEscaped.contains(executable)
+            || executable->isStrictMode())
+            m_createsArguments.add(inlineCallFrame);
+    }
+
     void observeBadArgumentsUse(Node* node)
     {
         if (!node)