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go-gcc.cc (class Bvariable): Remove Gcc_tree parent class. 

* go-gcc.cc (class Bvariable): Remove Gcc_tree parent class.  Add
	t_ and orig_type_ fields.  Add new two parameter constructor.  Add
	get_tree and get_decl methods.
	(Gcc_backend::var_expression): Pass location to var get_tree.
	(Gcc_backend::global_variable): Don't add VIEW_CONVERT_EXPR.  Use
	two parameter constructor for Bvariable.
	(Gcc_backend::global_variable_set_init): Don't remove
	VIEW_CONVERT_EXPR.  Use var get_decl, not get_tree.
	(Gcc_backend::write_global_definitions): Likewise.
	(Gcc_backend::init_statement): Call var get_decl, not get_tree.
	(Gcc_backend::block): Likewise.
	(Gcc_backend::implicit_variable_set_init): Likewise.
	(Gcc_backend::immutable_struct_set_init): Likewise.
	(Gcc_backend::function_set_parameters): Likewise.

From-SVN: r231894
This commit is contained in:
Ian Lance Taylor 2015-12-22 01:58:17 +00:00 committed by Ian Lance Taylor
parent 18fb580c1e
commit 399f5feb92
2 changed files with 80 additions and 32 deletions
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17
gcc/go/ChangeLog
View File

@ -1,3 +1,20 @@
2015-12-21 Ian Lance Taylor <iant@google.com>
* go-gcc.cc (class Bvariable): Remove Gcc_tree parent class. Add
t_ and orig_type_ fields. Add new two parameter constructor. Add
get_tree and get_decl methods.
(Gcc_backend::var_expression): Pass location to var get_tree.
(Gcc_backend::global_variable): Don't add VIEW_CONVERT_EXPR. Use
two parameter constructor for Bvariable.
(Gcc_backend::global_variable_set_init): Don't remove
VIEW_CONVERT_EXPR. Use var get_decl, not get_tree.
(Gcc_backend::write_global_definitions): Likewise.
(Gcc_backend::init_statement): Call var get_decl, not get_tree.
(Gcc_backend::block): Likewise.
(Gcc_backend::implicit_variable_set_init): Likewise.
(Gcc_backend::immutable_struct_set_init): Likewise.
(Gcc_backend::function_set_parameters): Likewise.
2015-12-21 Ian Lance Taylor <iant@google.com>
* go-gcc.cc (Gcc_backend::global_variable): If type is zero-sized,

95
gcc/go/go-gcc.cc
View File

@ -109,14 +109,6 @@ class Bblock : public Gcc_tree
{ }
};
class Bvariable : public Gcc_tree
{
public:
Bvariable(tree t)
: Gcc_tree(t)
{ }
};
class Blabel : public Gcc_tree
{
public:
@ -125,6 +117,57 @@ class Blabel : public Gcc_tree
{ }
};
// Bvariable is a bit more complicated, because of zero-sized types.
// The GNU linker does not permit dynamic variables with zero size.
// When we see such a variable, we generate a version of the type with
// non-zero size. However, when referring to the global variable, we
// want an expression of zero size; otherwise, if, say, the global
// variable is passed to a function, we will be passing a
// non-zero-sized value to a zero-sized value, which can lead to a
// miscompilation.
class Bvariable
{
public:
Bvariable(tree t)
: t_(t), orig_type_(NULL)
{ }
Bvariable(tree t, tree orig_type)
: t_(t), orig_type_(orig_type)
{ }
// Get the tree for use as an expression.
tree
get_tree(Location) const;
// Get the actual decl;
tree
get_decl() const
{ return this->t_; }
private:
tree t_;
tree orig_type_;
};
// Get the tree of a variable for use as an expression. If this is a
// zero-sized global, create an expression that refers to the decl but
// has zero size.
tree
Bvariable::get_tree(Location location) const
{
if (this->orig_type_ == NULL
|| this->t_ == error_mark_node
|| TREE_TYPE(this->t_) == this->orig_type_)
return this->t_;
// Return *(orig_type*)&decl. */
tree t = build_fold_addr_expr_loc(location.gcc_location(), this->t_);
t = fold_build1_loc(location.gcc_location(), NOP_EXPR,
build_pointer_type(this->orig_type_), t);
return build_fold_indirect_ref_loc(location.gcc_location(), t);
}
// This file implements the interface between the Go frontend proper
// and the gcc IR. This implements specific instantiations of
// abstract classes defined by the Go frontend proper. The Go
@ -1158,9 +1201,9 @@ Gcc_backend::zero_expression(Btype* btype)
// An expression that references a variable.
Bexpression*
Gcc_backend::var_expression(Bvariable* var, Location)
Gcc_backend::var_expression(Bvariable* var, Location location)
{
tree ret = var->get_tree();
tree ret = var->get_tree(location);
if (ret == error_mark_node)
return this->error_expression();
return this->make_expression(ret);
@ -1894,7 +1937,7 @@ Gcc_backend::expression_statement(Bexpression* expr)
Bstatement*
Gcc_backend::init_statement(Bvariable* var, Bexpression* init)
{
tree var_tree = var->get_tree();
tree var_tree = var->get_decl();
tree init_tree = init->get_tree();
if (var_tree == error_mark_node || init_tree == error_mark_node)
return this->error_statement();
@ -2264,7 +2307,7 @@ Gcc_backend::block(Bfunction* function, Bblock* enclosing,
pv != vars.end();
++pv)
{
*pp = (*pv)->get_tree();
*pp = (*pv)->get_decl();
if (*pp != error_mark_node)
pp = &DECL_CHAIN(*pp);
}
@ -2420,11 +2463,7 @@ Gcc_backend::global_variable(const std::string& package_name,
go_preserve_from_gc(decl);
if (orig_type_tree != type_tree)
decl = fold_build1_loc(location.gcc_location(), VIEW_CONVERT_EXPR,
orig_type_tree, decl);
return new Bvariable(decl);
return new Bvariable(decl, orig_type_tree);
}
// Set the initial value of a global variable.
@ -2436,13 +2475,9 @@ Gcc_backend::global_variable_set_init(Bvariable* var, Bexpression* expr)
if (expr_tree == error_mark_node)
return;
gcc_assert(TREE_CONSTANT(expr_tree));
tree var_decl = var->get_tree();
tree var_decl = var->get_decl();
if (var_decl == error_mark_node)
return;
// Undo the VIEW_CONVERT_EXPR that may have been added by
// global_variable.
if (TREE_CODE(var_decl) == VIEW_CONVERT_EXPR)
var_decl = TREE_OPERAND(var_decl, 0);
DECL_INITIAL(var_decl) = expr_tree;
// If this variable goes in a unique section, it may need to go into
@ -2668,7 +2703,7 @@ Gcc_backend::implicit_variable_set_init(Bvariable* var, const std::string&,
Btype*, bool, bool, bool is_common,
Bexpression* init)
{
tree decl = var->get_tree();
tree decl = var->get_decl();
tree init_tree;
if (init == NULL)
init_tree = NULL_TREE;
@ -2762,7 +2797,7 @@ Gcc_backend::immutable_struct_set_init(Bvariable* var, const std::string&,
bool, bool is_common, Btype*, Location,
Bexpression* initializer)
{
tree decl = var->get_tree();
tree decl = var->get_decl();
tree init_tree = initializer->get_tree();
if (decl == error_mark_node || init_tree == error_mark_node)
return;
@ -2981,7 +3016,7 @@ Gcc_backend::function_set_parameters(Bfunction* function,
pv != param_vars.end();
++pv)
{
*pp = (*pv)->get_tree();
*pp = (*pv)->get_decl();
gcc_assert(*pp != error_mark_node);
pp = &DECL_CHAIN(*pp);
}
@ -3037,14 +3072,10 @@ Gcc_backend::write_global_definitions(
p != variable_decls.end();
++p)
{
if ((*p)->get_tree() != error_mark_node)
tree v = (*p)->get_decl();
if (v != error_mark_node)
{
tree t = (*p)->get_tree();
// Undo the VIEW_CONVERT_EXPR that may have been added by
// global_variable.
if (TREE_CODE(t) == VIEW_CONVERT_EXPR)
t = TREE_OPERAND(t, 0);
defs[i] = t;
defs[i] = v;
go_preserve_from_gc(defs[i]);
++i;
}