NOT FOR COMMITTING: Add fast side-effect free floating point expressions.

src/ia32/codegen-ia32.cc

Index: src/ia32/codegen-ia32.cc
===================================================================
--- src/ia32/codegen-ia32.cc	(revision 3987)
+++ src/ia32/codegen-ia32.cc	(working copy)
@@ -38,6 +38,7 @@
 #include "regexp-stack.h"
 #include "register-allocator-inl.h"
 #include "runtime.h"
+#include "safe-codegen-ia32.h"
 #include "scopes.h"
 #include "virtual-frame-inl.h"
 
@@ -589,6 +590,31 @@
 }
 
 
+void CodeGenerator::LoadPossiblySafeExpression(Expression* expr) {
+  SafeSyntaxChecker checker;
+  if (checker.Check(expr)) {
+    __ IncrementCounter(&Counters::safe_expression_tried, 1);
+    JumpTarget unsafe;
+    JumpTarget done;
+    Result scratch = allocator_->Allocate();
+    ASSERT(scratch.is_register());
+    Result result = allocator_->Allocate();
+    ASSERT(result.is_register());
+    SafeGenerator safe_generator(masm_, &unsafe, this, &scratch, &result);
+    result = safe_generator.Generate(expr);
+    frame()->Push(&result);
+    __ IncrementCounter(&Counters::safe_expression_succeeded, 1);
+    done.Jump();
+
+    unsafe.Bind();
+    Load(expr);
+    done.Bind();
+  } else {
+    Load(expr);
+  }
+}
+
+
 ArgumentsAllocationMode CodeGenerator::ArgumentsMode() {
   if (scope()->arguments() == NULL) return NO_ARGUMENTS_ALLOCATION;
   ASSERT(scope()->arguments_shadow() != NULL);
@@ -2922,7 +2948,7 @@
   Comment cmnt(masm_, "[ ReturnStatement");
 
   CodeForStatementPosition(node);
-  Load(node->expression());
+  LoadPossiblySafeExpression(node->expression());
   Result return_value = frame_->Pop();
   masm()->WriteRecordedPositions();
   if (function_return_is_shadowed_) {
@@ -4745,7 +4771,7 @@
   if (node->is_compound()) {
     Result result = LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
     frame()->Push(&result);
-    Load(node->value());
+    LoadPossiblySafeExpression(node->value());
 
     bool overwrite_value =
         (node->value()->AsBinaryOperation() != NULL &&
@@ -4754,7 +4780,7 @@
                            node->type(),
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
-    Load(node->value());
+    LoadPossiblySafeExpression(node->value());
   }
 
   // Perform the assignment.
@@ -4822,7 +4848,7 @@
     }
     Result value = EmitNamedLoad(name, var != NULL);
     frame()->Push(&value);
-    Load(node->value());
+    LoadPossiblySafeExpression(node->value());
 
     bool overwrite_value =
         (node->value()->AsBinaryOperation() != NULL &&
@@ -4831,7 +4857,7 @@
                            node->type(),
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
-    Load(node->value());
+    LoadPossiblySafeExpression(node->value());
   }
 
   // Perform the assignment.  It is safe to ignore constants here.
@@ -4901,7 +4927,7 @@
     frame()->PushElementAt(1);
     Result value = EmitKeyedLoad();
     frame()->Push(&value);
-    Load(node->value());
+    LoadPossiblySafeExpression(node->value());
 
     bool overwrite_value =
         (node->value()->AsBinaryOperation() != NULL &&
@@ -4910,7 +4936,7 @@
                            node->type(),
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
-    Load(node->value());
+    LoadPossiblySafeExpression(node->value());
   }
 
   // Perform the assignment.  It is safe to ignore constants here.
@@ -5020,7 +5046,7 @@
     frame_->Push(Factory::undefined_value());
     int arg_count = args->length();
     for (int i = 0; i < arg_count; i++) {
-      Load(args->at(i));
+      LoadPossiblySafeExpression(args->at(i));
     }
 
     // Prepare the stack for the call to ResolvePossiblyDirectEval.
@@ -5069,7 +5095,7 @@
     // Load the arguments.
     int arg_count = args->length();
     for (int i = 0; i < arg_count; i++) {
-      Load(args->at(i));
+      LoadPossiblySafeExpression(args->at(i));
     }
 
     // Push the name of the function onto the frame.
@@ -5140,7 +5166,7 @@
         // Load the arguments.
         int arg_count = args->length();
         for (int i = 0; i < arg_count; i++) {
-          Load(args->at(i));
+          LoadPossiblySafeExpression(args->at(i));
         }
 
         // Push the name of the function onto the frame.