From 80048c14b1a1902f7db81ab88868eb4952b6baff Mon Sep 17 00:00:00 2001
From: "keuchel@chromium.org"
 <keuchel@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Thu, 6 Oct 2011 15:24:20 +0000
Subject: [PATCH] Fix load of potentially eval-shadowed let bindings.

BUG=
TEST=test/mjsunit/harmony/block-let-semantics.js

Review URL: http://codereview.chromium.org/8118032

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9541 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/arm/full-codegen-arm.cc                 | 12 ++++++++++--
 src/ia32/full-codegen-ia32.cc               | 10 ++++++++--
 src/x64/full-codegen-x64.cc                 | 10 ++++++++--
 test/mjsunit/harmony/block-let-semantics.js | 25 ++++++++++++++++++++++++-
 4 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 2ee1594..ba21802 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -1225,9 +1225,17 @@ void FullCodeGenerator::EmitDynamicLookupFastCase(Variable* var,
   } else if (var->mode() == Variable::DYNAMIC_LOCAL) {
     Variable* local = var->local_if_not_shadowed();
     __ ldr(r0, ContextSlotOperandCheckExtensions(local, slow));
-    if (local->mode() == Variable::CONST) {
+    if (local->mode() == Variable::CONST ||
+        local->mode() == Variable::LET) {
       __ CompareRoot(r0, Heap::kTheHoleValueRootIndex);
-      __ LoadRoot(r0, Heap::kUndefinedValueRootIndex, eq);
+      if (local->mode() == Variable::CONST) {
+        __ LoadRoot(r0, Heap::kUndefinedValueRootIndex, eq);
+      } else {  // Variable::LET
+        __ b(ne, done);
+        __ mov(r0, Operand(var->name()));
+        __ push(r0);
+        __ CallRuntime(Runtime::kThrowReferenceError, 1);
+      }
     }
     __ jmp(done);
   }
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index d45a9cd..b66711f 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -1207,10 +1207,16 @@ void FullCodeGenerator::EmitDynamicLookupFastCase(Variable* var,
   } else if (var->mode() == Variable::DYNAMIC_LOCAL) {
     Variable* local = var->local_if_not_shadowed();
     __ mov(eax, ContextSlotOperandCheckExtensions(local, slow));
-    if (local->mode() == Variable::CONST) {
+    if (local->mode() == Variable::CONST ||
+        local->mode() == Variable::LET) {
       __ cmp(eax, isolate()->factory()->the_hole_value());
       __ j(not_equal, done);
-      __ mov(eax, isolate()->factory()->undefined_value());
+      if (local->mode() == Variable::CONST) {
+        __ mov(eax, isolate()->factory()->undefined_value());
+      } else {  // Variable::LET
+        __ push(Immediate(var->name()));
+        __ CallRuntime(Runtime::kThrowReferenceError, 1);
+      }
     }
     __ jmp(done);
   }
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 1d9b8ff..afcf50a 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -1184,10 +1184,16 @@ void FullCodeGenerator::EmitDynamicLookupFastCase(Variable* var,
   } else if (var->mode() == Variable::DYNAMIC_LOCAL) {
     Variable* local = var->local_if_not_shadowed();
     __ movq(rax, ContextSlotOperandCheckExtensions(local, slow));
-    if (local->mode() == Variable::CONST) {
+    if (local->mode() == Variable::CONST ||
+        local->mode() == Variable::LET) {
       __ CompareRoot(rax, Heap::kTheHoleValueRootIndex);
       __ j(not_equal, done);
-      __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
+      if (local->mode() == Variable::CONST) {
+        __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
+      } else {  // Variable::LET
+        __ Push(var->name());
+        __ CallRuntime(Runtime::kThrowReferenceError, 1);
+      }
     }
     __ jmp(done);
   }
diff --git a/test/mjsunit/harmony/block-let-semantics.js b/test/mjsunit/harmony/block-let-semantics.js
index 198c3b4..3819a9c 100644
--- a/test/mjsunit/harmony/block-let-semantics.js
+++ b/test/mjsunit/harmony/block-let-semantics.js
@@ -81,13 +81,20 @@ TestAll('f()(); let x; function f() { return function() { x += 1; } }');
 TestAll('f()(); let x; function f() { return function() { ++x; } }');
 TestAll('f()(); let x; function f() { return function() { x++; } }');
 
-// Use in before initialization with a dynamic lookup.
+// Use before initialization with a dynamic lookup.
 TestAll('eval("x + 1;"); let x;');
 TestAll('eval("x = 1;"); let x;');
 TestAll('eval("x += 1;"); let x;');
 TestAll('eval("++x;"); let x;');
 TestAll('eval("x++;"); let x;');
 
+// Use before initialization with check for eval-shadowed bindings.
+TestAll('function f() { eval("var y = 2;"); x + 1; }; f(); let x;');
+TestAll('function f() { eval("var y = 2;"); x = 1; }; f(); let x;');
+TestAll('function f() { eval("var y = 2;"); x += 1; }; f(); let x;');
+TestAll('function f() { eval("var y = 2;"); ++x; }; f(); let x;');
+TestAll('function f() { eval("var y = 2;"); x++; }; f(); let x;');
+
 // Test that variables introduced by function declarations are created and
 // initialized upon entering a function / block scope.
 function f() {
@@ -136,3 +143,19 @@ function f2() {
   }
   assertEquals(5, n());
 }
+
+// Test that resolution of let bound variables works with scopes that call eval.
+function outer() {
+  function middle() {
+    function inner() {
+      return x;
+    }
+    eval("1 + 1");
+    return x + inner();
+  }
+
+  let x = 1;
+  return middle();
+}
+
+assertEquals(2, outer());
-- 
2.7.4