Disable ES6 tail call elimination for native functions.

We don't want them to disappear from the stack traces.

BUG=v8:4698
LOG=N

Review URL: https://codereview.chromium.org/1818063002

Cr-Commit-Position: refs/heads/master@{#34957}

src/parsing/parser-base.h

@@ -108,6 +108,7 @@ class ParserBase : public Traits {
         stack_overflow_(false),
         allow_lazy_(false),
         allow_natives_(false),
+        allow_tailcalls_(false),
         allow_harmony_sloppy_(false),
         allow_harmony_sloppy_function_(false),
         allow_harmony_sloppy_let_(false),
@@ -129,6 +130,7 @@ class ParserBase : public Traits {
 
   ALLOW_ACCESSORS(lazy);
   ALLOW_ACCESSORS(natives);
+  ALLOW_ACCESSORS(tailcalls);
   ALLOW_ACCESSORS(harmony_sloppy);
   ALLOW_ACCESSORS(harmony_sloppy_function);
   ALLOW_ACCESSORS(harmony_sloppy_let);
@@ -918,6 +920,7 @@ class ParserBase : public Traits {
 
   bool allow_lazy_;
   bool allow_natives_;
+  bool allow_tailcalls_;
   bool allow_harmony_sloppy_;
   bool allow_harmony_sloppy_function_;
   bool allow_harmony_sloppy_let_;

src/parsing/parser.cc

@@ -783,6 +783,7 @@ Parser::Parser(ParseInfo* info)
   DCHECK(!info->script().is_null() || info->source_stream() != NULL);
   set_allow_lazy(info->allow_lazy_parsing());
   set_allow_natives(FLAG_allow_natives_syntax || info->is_native());
+  set_allow_tailcalls(FLAG_harmony_tailcalls && !info->is_native());
   set_allow_harmony_sloppy(FLAG_harmony_sloppy);
   set_allow_harmony_sloppy_function(FLAG_harmony_sloppy_function);
   set_allow_harmony_sloppy_let(FLAG_harmony_sloppy_let);
@@ -2680,7 +2681,7 @@ Statement* Parser::ParseReturnStatement(bool* ok) {
     }
 
     // ES6 14.6.1 Static Semantics: IsInTailPosition
-    if (FLAG_harmony_tailcalls && !is_sloppy(language_mode())) {
+    if (allow_tailcalls() && !is_sloppy(language_mode())) {
       function_state_->AddExpressionInTailPosition(return_value);
     }
   }

test/mjsunit/function-caller.js

@@ -47,7 +47,7 @@ f(null);
 eval('f(null)');
 
 // Check called from strict builtin functions.
-// [null, null].sort(f);  // Does not work because sort tail calls.
+[null, null].sort(f);
 [null].forEach(f, null);
 
 // Check called from sloppy builtin functions.

test/mjsunit/strict-mode.js

@@ -1149,7 +1149,7 @@ function CheckArgumentsPillDescriptor(func, name) {
 
   function strict() {
     "use strict";
-    // Returning result via local variable to avoid tail call optimization.
+    // Returning result via local variable to avoid tail call elimination.
     var res = return_my_caller();
     return res;
   }
@@ -1165,7 +1165,7 @@ function CheckArgumentsPillDescriptor(func, name) {
 (function TestNonStrictFunctionCallerPill() {
   function strict(n) {
     "use strict";
-    // Returning result via local variable to avoid tail call optimization.
+    // Returning result via local variable to avoid tail call elimination.
     var res = non_strict(n);
     return res;
   }
@@ -1195,7 +1195,7 @@ function CheckArgumentsPillDescriptor(func, name) {
 (function TestNonStrictFunctionCallerDescriptorPill() {
   function strict(n) {
     "use strict";
-    // Returning result via local variable to avoid tail call optimization.
+    // Returning result via local variable to avoid tail call elimination.
     var res = non_strict(n);
     return res;
   }