X87: Resolve references to "this" the same way as normal variables

src/x87/lithium-codegen-x87.cc

Index: src/x87/lithium-codegen-x87.cc
diff --git a/src/x87/lithium-codegen-x87.cc b/src/x87/lithium-codegen-x87.cc
index e04ceb2a7f97b9027db242a18e89ede00dd0eaa4..37c3f47a1b9598d384b9d6f89c2add3629ff7483 100644
--- a/src/x87/lithium-codegen-x87.cc
+++ b/src/x87/lithium-codegen-x87.cc
@@ -110,8 +110,8 @@ bool LCodeGen::GeneratePrologue() {
     // Sloppy mode functions and builtins need to replace the receiver with the
     // global proxy when called as functions (without an explicit receiver
     // object).
-    if (is_sloppy(info_->language_mode()) && info()->MayUseThis() &&
-        !info_->is_native()) {
+    if (is_sloppy(info()->language_mode()) && info()->MayUseThis() &&
+        !info()->is_native() && info()->scope()->has_this_declaration()) {
       Label ok;
       // +1 for return address.
       int receiver_offset = (scope()->num_parameters() + 1) * kPointerSize;
@@ -242,8 +242,9 @@ bool LCodeGen::GeneratePrologue() {
 
     // Copy parameters into context if necessary.
     int num_parameters = scope()->num_parameters();
-    for (int i = 0; i < num_parameters; i++) {
-      Variable* var = scope()->parameter(i);
+    int first_parameter = scope()->has_this_declaration() ? -1 : 0;
+    for (int i = first_parameter; i < num_parameters; i++) {
+      Variable* var = (i == -1) ? scope()->receiver() : scope()->parameter(i);
       if (var->IsContextSlot()) {
         int parameter_offset = StandardFrameConstants::kCallerSPOffset +
             (num_parameters - 1 - i) * kPointerSize;