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re PR go/61308 (gccgo: ICE in Expression::check_bounds [GoSmith])

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PR go/61308
	PR go/61866

compiler: Don't cast index expr to int before bounds check.

This fixes http://gcc.gnu.org/PR61866 : on a 32-bit system,
casting an int64 index to int drops the upper 32 bits of the
value, and thus can cause an out-of-range index to appear to
be in range.

This undoes part of change 1318:fa6e0c716dba
(https://codereview.appspot.com/104610044) and therefore
breaks http://gcc.gnu.org/PR61308 again.  I have a separate
patch for that (http://codereview.appspot.com/122020043).  In
addition to undoing part of that change, this patch adds code
to avoid a compiler crash.  This changes PR61308 from a
compiler crash to an incorrect error message.

From-SVN: r213616
This commit is contained in:
Ian Lance Taylor 2014-08-05 02:58:15 +00:00
parent cb7b4e7717
commit 6e4f9a957e
1 changed files with 16 additions and 3 deletions
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19
gcc/go/gofrontend/expressions.cc
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@ -3620,6 +3620,16 @@ Unary_expression::do_lower(Gogo*, Named_object*, Statement_inserter*, int)
return Expression::make_error(this->location());
}
// Check for an invalid pointer dereference. We need to do this
// here because Unary_expression::do_type will return an error type
// in this case. That can cause code to appear erroneous, and
// therefore disappear at lowering time, without any error message.
if (op == OPERATOR_MULT && expr->type()->points_to() == NULL)
{
this->report_error(_("expected pointer"));
return Expression::make_error(this->location());
}
if (op == OPERATOR_PLUS || op == OPERATOR_MINUS || op == OPERATOR_XOR)
{
Numeric_constant nc;
@ -9811,7 +9821,10 @@ Index_expression::do_lower(Gogo*, Named_object*, Statement_inserter*, int)
Type* type = left->type();
if (type->is_error())
return Expression::make_error(location);
{
go_assert(saw_errors());
return Expression::make_error(location);
}
else if (left->is_type_expression())
{
error_at(location, "attempt to index type expression");
@ -10298,9 +10311,9 @@ Array_index_expression::do_get_backend(Translate_context* context)
go_assert(saw_errors());
return context->backend()->error_expression();
}
Expression* start_expr = Expression::make_cast(int_type, this->start_, loc);
Bexpression* bad_index =
Expression::check_bounds(start_expr, loc)->get_backend(context);
Expression::check_bounds(this->start_, loc)->get_backend(context);
Bexpression* start = this->start_->get_backend(context);
start = gogo->backend()->convert_expression(int_btype, start, loc);