Fix some bugs in the code generator

arguments can't be used as lvalue in strict mode. We however also threw
an error in some cases where it was used as an rvalue, e.g. in
(arguments < 10)
the delete operator should throw a syntax error in strict mode on all
unqualified variables
Optimize the identifier() code a little: arguments and local variables
inside eval do not need to be looked up by name.

Change-Id: If3e9305187acf72820c5164aa9754927a2c4d5d5
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 27 insertions, 12 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 8c24994048..293086378e 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -1120,7 +1120,6 @@ bool Codegen::visit(BinaryExpression *ast)
     }
 
     V4IR::Expr* left = *expression(ast->left);
-    throwSyntaxErrorOnEvalOrArgumentsInStrictMode(left, ast->left->lastSourceLocation());
 
     switch (ast->op) {
     case QSOperator::Or:
@@ -1128,6 +1127,7 @@ bool Codegen::visit(BinaryExpression *ast)
         break;
 
     case QSOperator::Assign: {
+        throwSyntaxErrorOnEvalOrArgumentsInStrictMode(left, ast->left->lastSourceLocation());
         V4IR::Expr* right = *expression(ast->right);
         if (! (left->asTemp() || left->asName() || left->asSubscript() || left->asMember()))
             throwReferenceError(ast->operatorToken, QCoreApplication::translate("qv4codegen", "left-hand side of assignment operator is not an lvalue"));
@@ -1154,6 +1154,7 @@ bool Codegen::visit(BinaryExpression *ast)
     case QSOperator::InplaceRightShift:
     case QSOperator::InplaceURightShift:
     case QSOperator::InplaceXor: {
+        throwSyntaxErrorOnEvalOrArgumentsInStrictMode(left, ast->left->lastSourceLocation());
         V4IR::Expr* right = *expression(ast->right);
         if (!left->isLValue())
             throwSyntaxError(ast->operatorToken, QCoreApplication::translate("qv4codegen", "left-hand side of inplace operator is not an lvalue"));
@@ -1281,9 +1282,10 @@ bool Codegen::visit(DeleteExpression *ast)
 {
     V4IR::Expr* expr = *expression(ast->expression);
     // Temporaries cannot be deleted
-    if (expr->asTemp() && expr->asTemp()->index < _env->members.size()) {
+    V4IR::Temp *t = expr->asTemp();
+    if (t && t->index < _env->members.size()) {
         // Trying to delete a function argument might throw.
-        if (_function->isStrict && expr->asTemp()->index < 0)
+        if (_function->isStrict)
             throwSyntaxError(ast->deleteToken, "Delete of an unqualified identifier in strict mode.");
         _expr.code = _block->CONST(V4IR::BoolType, 0);
         return false;
@@ -1346,22 +1348,30 @@ V4IR::Expr *Codegen::identifier(const QString &name, int line, int col)
     V4IR::Function *f = _function;
 
     while (f && e->parent) {
-        if ((f->usesArgumentsObject && name == "arguments") || (!f->isStrict && f->hasDirectEval) || f->insideWithOrCatch || (f->isNamedExpression && f->name == name))
-            break;
+        if (f->insideWithOrCatch || (f->isNamedExpression && f->name == name))
+            return _block->NAME(name, line, col);
+
         int index = e->findMember(name);
         assert (index < e->members.size());
         if (index != -1) {
-            return _block->LOCAL(index, scope);
+            V4IR::Temp *t = _block->LOCAL(index, scope);
+            if (name == "arguments" || name == "eval")
+                t->isArgumentsOrEval = true;
+            return t;
         }
         const int argIdx = f->indexOfArgument(&name);
         if (argIdx != -1)
             return _block->ARG(argIdx, scope);
+
+        if (!f->isStrict && f->hasDirectEval)
+            return _block->NAME(name, line, col);
+
         ++scope;
         e = e->parent;
         f = f->outer;
     }
 
-    if (!e->parent && (!f || !f->insideWithOrCatch) && _mode != EvalCode && _mode != QmlBinding && (!f || f->name != name))
+    if (!e->parent && (!f || !f->insideWithOrCatch) && _mode != EvalCode && _mode != QmlBinding)
         return _block->GLOBALNAME(name, line, col);
 
     // global context or with. Lookup by name
@@ -1836,7 +1846,7 @@ V4IR::Function *Codegen::defineFunction(const QString &name, AST::Node *ast,
         }
     }
     if (_function->usesArgumentsObject) {
-        move(_block->NAME("arguments", ast->firstSourceLocation().startLine, ast->firstSourceLocation().startColumn),
+        move(identifier("arguments", ast->firstSourceLocation().startLine, ast->firstSourceLocation().startColumn),
              _block->CALL(_block->NAME(V4IR::Name::builtin_setup_argument_object,
                      ast->firstSourceLocation().startLine, ast->firstSourceLocation().startColumn), 0));
     }
@@ -2520,11 +2530,16 @@ void Codegen::throwSyntaxErrorOnEvalOrArgumentsInStrictMode(V4IR::Expr *expr, co
 {
     if (!_env->isStrict)
         return;
-    V4IR::Name *n = expr->asName();
-    if (!n)
+    if (V4IR::Name *n = expr->asName()) {
+        if (*n->id != QLatin1String("eval") && *n->id != QLatin1String("arguments"))
+            return;
+    } else if (V4IR::Temp *t = expr->asTemp()) {
+        if (!t->isArgumentsOrEval)
+            return;
+    } else {
         return;
-    if (*n->id == QLatin1String("eval") || *n->id == QLatin1String("arguments"))
-        throwSyntaxError(loc, QCoreApplication::translate("qv4codegen", "Variable name may not be eval or arguments in strict mode"));
+    }
+    throwSyntaxError(loc, QCoreApplication::translate("qv4codegen", "Variable name may not be eval or arguments in strict mode"));
 }
 
 void Codegen::throwSyntaxError(const SourceLocation &loc, const QString &detail)