Go patch committed: Explicitly convert between type aliases
Ian Lance Taylor
iant@golang.org
Thu Oct 26 23:29:00 GMT 2017
This patch adds an explicit conversion between type aliases.
Otherwise we can get a crash in the backend when GCC sees a
fold_convert_loc between two record types that the GCC backend appear
to be different. Adding the explicit conversion will insert a
VIEW_CONVERT_EXPR where needed. The test case is
https://golang.org/cl/73790. Bootstrapped and ran Go testsuite on
x86_64-pc-linux-gnu. Committed to mainline.
Ian
-------------- next part --------------
Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE (revision 254090)
+++ gcc/go/gofrontend/MERGE (working copy)
@@ -1,4 +1,4 @@
-a409ac2c78899e638a014c97891925bec93cb3ad
+64d570c590a76921cbdca4efb22e4675e19cc809
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
Index: gcc/go/gofrontend/expressions.cc
===================================================================
--- gcc/go/gofrontend/expressions.cc (revision 254090)
+++ gcc/go/gofrontend/expressions.cc (working copy)
@@ -144,8 +144,8 @@ Expression::convert_for_assignment(Gogo*
|| rhs->is_error_expression())
return Expression::make_error(location);
- if (lhs_type->forwarded() != rhs_type->forwarded()
- && lhs_type->interface_type() != NULL)
+ bool are_identical = Type::are_identical(lhs_type, rhs_type, false, NULL);
+ if (!are_identical && lhs_type->interface_type() != NULL)
{
if (rhs_type->interface_type() == NULL)
return Expression::convert_type_to_interface(lhs_type, rhs, location);
@@ -153,8 +153,7 @@ Expression::convert_for_assignment(Gogo*
return Expression::convert_interface_to_interface(lhs_type, rhs, false,
location);
}
- else if (lhs_type->forwarded() != rhs_type->forwarded()
- && rhs_type->interface_type() != NULL)
+ else if (!are_identical && rhs_type->interface_type() != NULL)
return Expression::convert_interface_to_type(lhs_type, rhs, location);
else if (lhs_type->is_slice_type() && rhs_type->is_nil_type())
{
@@ -165,8 +164,15 @@ Expression::convert_for_assignment(Gogo*
}
else if (rhs_type->is_nil_type())
return Expression::make_nil(location);
- else if (Type::are_identical(lhs_type, rhs_type, false, NULL))
+ else if (are_identical)
{
+ if (lhs_type->forwarded() != rhs_type->forwarded())
+ {
+ // Different but identical types require an explicit
+ // conversion. This happens with type aliases.
+ return Expression::make_cast(lhs_type, rhs, location);
+ }
+
// No conversion is needed.
return rhs;
}
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