Detect conflicting variable bindings in harmony mode.

src/ia32/full-codegen-ia32.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
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 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2140 matching lines @@
   // Push copy of the first argument or undefined if it doesn't exist.
   if (arg_count > 0) {
     __ push(Operand(esp, arg_count * kPointerSize));
   } else {
     __ push(Immediate(isolate()->factory()->undefined_value()));
   }
 
   // Push the receiver of the enclosing function.
   __ push(Operand(ebp, (2 + info_->scope()->num_parameters()) * kPointerSize));
 
-  // Push the strict mode flag.
-  __ push(Immediate(Smi::FromInt(strict_mode_flag())));
+  // Push the strict mode flag. In harmony mode every eval call
+  // is a strict mode eval call.

[Lasse Reichstein, 2011/09/01 07:34:04]

How come this invariant isn't shown in the strict_mode_flag to begin with? I.e.,
should strict_mode_flag be able to return anything but kStrictMode in Harmony
mode?

[Steven, 2011/09/01 15:01:33]

In fact, harmony mode should be an extension of the strict mode, so that we
could set that in strict_mode_flag() and assume strict mode semantics
everywhere. However, then we would have to do the same for the parser for
consistency. Andreas and I agreed that we would want to make the impact of new
features on existing functionality as small as possible if it does not
complicate things. Leaking
var declarations from 'eval' is nasty so we would want to disallow that.
On 2011/09/01 07:34:04, Lasse Reichstein wrote:

+  StrictModeFlag strict_mode = strict_mode_flag();
+  if (FLAG_harmony_block_scoping) {
+    strict_mode = kStrictMode;
+  }
+  __ push(Immediate(Smi::FromInt(strict_mode)));
 
   __ CallRuntime(flag == SKIP_CONTEXT_LOOKUP
                  ? Runtime::kResolvePossiblyDirectEvalNoLookup
                  : Runtime::kResolvePossiblyDirectEval, 4);
 }
 
 
 void FullCodeGenerator::VisitCall(Call* expr) {
 #ifdef DEBUG
   // We want to verify that RecordJSReturnSite gets called on all paths
@@ skipping 2151 matching lines @@
   __ add(Operand(edx), Immediate(masm_->CodeObject()));
   __ jmp(Operand(edx));
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32