Revert of PPC: Resolve references to "this" the same way as normal variables...

Revert of PPC: Resolve references to "this" the same way as normal variables (patchset #1 id:1 of https://codereview.chromium.org/1129803003/)

Reason for revert:
Original commit was reverted.

Original issue's description:
> PPC: Resolve references to "this" the same way as normal variables
>
> Port 18619d35
>
> Original commit message:
> Make the parser handle references to "this" as unresolved variables, so the
> same logic as for the rest of function parameters is used for the receiver.
> Minor additions to the code generation handle copying the receiver to the
> context, along with the rest of the function parameters.
>
> Based on work by Adrian Perez de Castro <aperez@igalia.com>.
>
> R=wingo@igalia.com, dstence@us.ibm.com,  michael_dawson@ca.ibm.com
> BUG=
>
> Committed: https://crrev.com/e0ec097b2f49c4c99a2e9490f4b1a09e02abfd4d
> Cr-Commit-Position: refs/heads/master@{#28272}

TBR=dstence@us.ibm.com,michael_dawson@ca.ibm.com,wingo@igalia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1132513005

Cr-Commit-Position: refs/heads/master@{#28305}

src/ppc/full-codegen-ppc.cc

@@ -124,7 +124,7 @@ void FullCodeGenerator::Generate() {
   // global proxy when called as functions (without an explicit receiver
   // object).
   if (is_sloppy(info->language_mode()) && !info->is_native() &&
-      info->MayUseThis() && info->scope()->has_this_declaration()) {
+      info->MayUseThis()) {
     Label ok;
     int receiver_offset = info->scope()->num_parameters() * kPointerSize;
     __ LoadP(r5, MemOperand(sp, receiver_offset), r0);
@@ -221,9 +221,8 @@ void FullCodeGenerator::Generate() {
     __ StoreP(r3, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = info->scope()->num_parameters();
-    int first_parameter = info->scope()->has_this_declaration() ? -1 : 0;
-    for (int i = first_parameter; i < num_parameters; i++) {
-      Variable* var = (i == -1) ? scope()->receiver() : scope()->parameter(i);
+    for (int i = 0; i < num_parameters; i++) {
+      Variable* var = scope()->parameter(i);
       if (var->IsContextSlot()) {
         int parameter_offset = StandardFrameConstants::kCallerSPOffset +
                                (num_parameters - 1 - i) * kPointerSize;
@@ -3050,9 +3049,8 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
   __ LoadP(r7, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
 
   // r6: the receiver of the enclosing function.
-  Variable* this_var = scope()->LookupThis();
-  DCHECK_NOT_NULL(this_var);
-  GetVar(r6, this_var);
+  int receiver_offset = 2 + info_->scope()->num_parameters();
+  __ LoadP(r6, MemOperand(fp, receiver_offset * kPointerSize), r0);
 
   // r5: language mode.
   __ LoadSmiLiteral(r5, Smi::FromInt(language_mode()));

src/ppc/lithium-codegen-ppc.cc

@@ -119,7 +119,7 @@ bool LCodeGen::GeneratePrologue() {
     // global proxy when called as functions (without an explicit receiver
     // object).
     if (is_sloppy(info_->language_mode()) && info()->MayUseThis() &&
-        !info_->is_native() && info_->scope()->has_this_declaration()) {
+        !info_->is_native()) {
       Label ok;
       int receiver_offset = info_->scope()->num_parameters() * kPointerSize;
       __ LoadP(r5, MemOperand(sp, receiver_offset));
@@ -199,9 +199,8 @@ bool LCodeGen::GeneratePrologue() {
     __ StoreP(r3, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = scope()->num_parameters();
-    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);
+    for (int i = 0; i < num_parameters; i++) {
+      Variable* var = scope()->parameter(i);
       if (var->IsContextSlot()) {
         int parameter_offset = StandardFrameConstants::kCallerSPOffset +
                                (num_parameters - 1 - i) * kPointerSize;