===================================================================
@@ -338,6 +338,9 @@ class Gcc_backend : public Backend
Btype*
fill_in_array(Btype*, Btype*, Bexpression*);
+
+ tree
+ non_zero_size_type(tree);
};
// A helper function.
@@ -870,9 +873,27 @@ Gcc_backend::init_statement(Bvariable* v
if (var_tree == error_mark_node || init_tree == error_mark_node)
return this->error_statement();
gcc_assert(TREE_CODE(var_tree) == VAR_DECL);
- DECL_INITIAL(var_tree) = init_tree;
- return this->make_statement(build1_loc(DECL_SOURCE_LOCATION(var_tree),
- DECL_EXPR, void_type_node, var_tree));
+
+ // To avoid problems with GNU ld, we don't make zero-sized
+ // externally visible variables. That might lead us to doing an
+ // initialization of a zero-sized expression to a non-zero sized
+ // variable, or vice-versa. Avoid crashes by omitting the
+ // initializer. Such initializations don't mean anything anyhow.
+ if (int_size_in_bytes(TREE_TYPE(var_tree)) != 0
+ && init_tree != NULL_TREE
+ && int_size_in_bytes(TREE_TYPE(init_tree)) != 0)
+ {
+ DECL_INITIAL(var_tree) = init_tree;
+ init_tree = NULL_TREE;
+ }
+
+ tree ret = build1_loc(DECL_SOURCE_LOCATION(var_tree), DECL_EXPR,
+ void_type_node, var_tree);
+ if (init_tree != NULL_TREE)
+ ret = build2_loc(DECL_SOURCE_LOCATION(var_tree), COMPOUND_EXPR,
+ void_type_node, init_tree, ret);
+
+ return this->make_statement(ret);
}
// Assignment.
@@ -885,6 +906,18 @@ Gcc_backend::assignment_statement(Bexpre
tree rhs_tree = rhs->get_tree();
if (lhs_tree == error_mark_node || rhs_tree == error_mark_node)
return this->error_statement();
+
+ // To avoid problems with GNU ld, we don't make zero-sized
+ // externally visible variables. That might lead us to doing an
+ // assignment of a zero-sized expression to a non-zero sized
+ // expression; avoid crashes here by avoiding assignments of
+ // zero-sized expressions. Such assignments don't really mean
+ // anything anyhow.
+ if (int_size_in_bytes(TREE_TYPE(lhs_tree)) == 0
+ || int_size_in_bytes(TREE_TYPE(rhs_tree)) == 0)
+ return this->compound_statement(this->expression_statement(lhs),
+ this->expression_statement(rhs));
+
return this->make_statement(fold_build2_loc(location.gcc_location(),
MODIFY_EXPR,
void_type_node,
@@ -1178,6 +1211,48 @@ Gcc_backend::block_statement(Bblock* bbl
return this->make_statement(bind_tree);
}
+// This is not static because we declare it with GTY(()) in go-c.h.
+tree go_non_zero_struct;
+
+// Return a type corresponding to TYPE with non-zero size.
+
+tree
+Gcc_backend::non_zero_size_type(tree type)
+{
+ if (int_size_in_bytes(type) != 0)
+ return type;
+
+ switch (TREE_CODE(type))
+ {
+ case RECORD_TYPE:
+ {
+ if (go_non_zero_struct == NULL_TREE)
+ {
+ type = make_node(RECORD_TYPE);
+ tree field = build_decl(UNKNOWN_LOCATION, FIELD_DECL,
+ get_identifier("dummy"),
+ boolean_type_node);
+ DECL_CONTEXT(field) = type;
+ TYPE_FIELDS(type) = field;
+ layout_type(type);
+ go_non_zero_struct = type;
+ }
+ return go_non_zero_struct;
+ }
+
+ case ARRAY_TYPE:
+ {
+ tree element_type = non_zero_size_type(TREE_TYPE(type));
+ return build_array_type_nelts(element_type, 1);
+ }
+
+ default:
+ gcc_unreachable();
+ }
+
+ gcc_unreachable();
+}
+
// Make a global variable.
Bvariable*
@@ -1193,6 +1268,10 @@ Gcc_backend::global_variable(const std::
if (type_tree == error_mark_node)
return this->error_variable();
+ // The GNU linker does not like dynamic variables with zero size.
+ if ((is_external || !is_hidden) && int_size_in_bytes(type_tree) == 0)
+ type_tree = this->non_zero_size_type(type_tree);
+
std::string var_name(package_name);
var_name.push_back('.');
var_name.append(name);
===================================================================
@@ -34,7 +34,7 @@ target_libs="target-libgo target-libffi"
# compiler during stage 1.
lang_requires_boot_languages=c++
-gtfiles="\$(srcdir)/go/go-lang.c"
+gtfiles="\$(srcdir)/go/go-lang.c \$(srcdir)/go/go-c.h"
# Do not build by default.
build_by_default="no"
===================================================================
@@ -843,7 +843,9 @@ Gogo::write_globals()
this->backend()->global_variable_set_init(var,
tree_to_expr(init));
}
- else if (is_sink)
+ else if (is_sink
+ || int_size_in_bytes(TREE_TYPE(init)) == 0
+ || int_size_in_bytes(TREE_TYPE(vec[i])) == 0)
var_init_tree = init;
else
var_init_tree = fold_build2_loc(no->location().gcc_location(),
===================================================================
@@ -69,6 +69,8 @@ extern void go_write_export_data (const
extern const char *go_read_export_data (int, off_t, char **, size_t *, int *);
+extern GTY(()) tree go_non_zero_struct;
+
#if defined(__cplusplus) && !defined(ENABLE_BUILD_WITH_CXX)
} /* End extern "C". */
#endif