libabigail/include/abg-traverse.h
Dodji Seketeli 8b28d171c3 Canonicalize types either early or late after TU reading
While trying to diff two identical files (abidiff foo.so foo.so) it
appeared that canonicalizing types during e.g, the DWARF reading
process was leading to subtle errors because it's extremely hard to
know when a type is complete.  That is, during the building of a class
type C, a pointer to C can be built before C is complete.  Worse, even
after reading the DIE (from DWARF) of class C, there can be DIE seen
later in the translation unit that modifies type C.  In these late
cases, one needs to wait -- not only until C is fully built, but also
sometimes, after the translation unit is fully built -- to
canonicalize C and then the pointer to C.  This kind of things.

So now there are two possible points in time when canonicalization of
a type can happen.  It can happen early, when the type is built.  This
is the case for basic types and composite types for which all
sub-types are canonicalized already.  It can happen late, right after
we've finished reading the debug info for the current translation
unit.

So this patch fixes the IR traversal and uses that to walk the
translation unit (or even types) after it's built.  It does away with
the first attempt to perform early canonicalizing only.

The patch also handles type canonicalizing while reading xml-abi
format.

	* include/abg-fwd.h (is_class_type)
	(type_has_non_canonicalized_subtype): Declare new functions.
	(is_member_type): Remove the overload that takes a decl_base_sptr.
	It's superfluous.  We just need the one that takes a
	type_base_sptr.
	* include/abg-ir.h (translation_unit::{is_constructed,
	set_is_constructed}): Add new methods.
	(class_decl::has_virtual_member_functions): Likewise.
	(class decl_base): Makes it virtually inherit ir_traversable_base.
	(class type_base): Make this virtually inherit traversable_base
	too.
	(type_base::canonicalize): Renamed enable_canonical_equality
	into this.
	(type_base::traverse): Declare new virtual method.
	(canonicalize): Renamed enable_canonical_equality into this.
	(scope_type_decl::traverse): Declare new virtual method.
	(namespace_decl::get_pretty_representation): Declare new virtual
	method.
	(function_type::traverse): Likewise.
	(class_decl::base_spec::traverse): Likewise.
	(ir_node_visitor::visit): Remove the overloads and replace each of
	them with a pair of ...
	(ir_node_visitor::{visit_begin, visit_end}): ... of these.
	* include/abg-traverse.h (traversable_base::visiting): New
	method.
	(traversable_base::visiting_): New data member.
	(traversable_base::traversable_base): New constructor.
	* src/abg-ir.cc ({scope_decl, type_decl, namespace_decl,
	qualified_type_def, pointer_type_def, reference_type_def,
	array_type_def, enum_type_decl, typedef_decl, var_decl,
	function_decl, function_decl::parameter, class_decl,
	class_decl::member_function_template,
	class_decl::member_class_template, function_tdecl,
	class_tdecl}::traverse): Fix this to properly set the
	traversable_base::visiting_ flag and to reflect the new signatures
	of the ir_node_visitor methods.
	({type_base, scope_type_decl, function_type,
	class_decl::base_spec}::traverse): New method.
	(type_base::get_canonical_type_for): Handle the case of the type
	already having a canonical type.  Properly hash the type using the
	dynamic type hasher.  Look through declaration-only classes to
	consider the definition of the class instead.  Fix logic to have a
	single pointer of return, to ease debugging.
	(canonicalize): Renamed enable_canonical_equality into this.
	(namespace_decl::get_pretty_representation): Define new method.
	(ir_node_visitor::visit): Replace each of these overloads with a
	pair of visit_begin/visit_end ones.
	(translation_unit::priv::is_constructed_): New data member.
	(translation_unit::priv::priv): Initialize it.
	(translation_unit::{is_constructed, set_is_constructed}): Define
	new methods.
	(is_member_type(const decl_base_sptr)): Remove.
	(is_class_type(decl_base *d)): Define new function.
	(class_decl::has_virtual_member_functions): Define new method.
	(equals(const class_decl&, const class_decl&, change_kind*)): If
	the containing translation unit is not constructed yet, do not
	take virtual member functions in account when comparing the
	classes.  This is because when reading from DWARF, there can be
	DIEs that change the number of virtual member functions after the
	DIE of the class.  So one needs to start taking virtual members
	into account only after the translation unit has been constructed.
	(class non_canonicalized_subtype_detector): Define new type.
	(type_has_non_canonicalized_subtype): Define new function.
	* src/abg-corpus.cc (symtab_build_visitor_type::visit): Renamed
	this into symtab_build_visitor_type::visit_end.
	* src/abg-dwarf-reader.cc (die_type_map_type): New typedef.
	(die_class_map_type): This is now a typedef on a map of
	Dwarf_Off/class_decl_sptr.
	(read_context::{die_type_map_, alternate_die_type_map_,
	types_to_canonicalize_, alt_types_to_canonicalize_}): New data
	members.
	(read_context::{associate_die_to_decl,
	associate_die_to_decl_primary}): Make these methods public.
	(read_context::{associate_die_to_type,
	lookup_type_from_die_offset, is_wip_class_die_offset,
	types_to_canonicalize, schedule_type_for_canonicalization}):
	Define new methods.
	(build_type_decl, build_enum_type)
	(build_class_type_and_add_to_ir, build_qualified_type)
	(build_pointer_type_def, build_reference_type, build_array_type)
	(build_typedef_type, build_function_decl): Do not canonicalize
	types here.
	(maybe_canonicalize_type): Define new function.
	(build_ir_node_from_die): Take a new flag that says if the ir node
	is a member type/function or not. Early-canonicalize base types.
	Canonicalize composite types that have only canonicalized
	sub-types.  Schedule the other types for late canonicalizing.  For
	class types, early canonicalize those that are non-member types,
	that are fully constructed and that have only canonicalized
	sub-types.  Adjust to the new signature of build_ir_node_from_die.
	(get_scope_for_die, build_namespace_decl_and_add_to_ir)
	(build_qualified_type, build_pointer_type_def)
	(build_reference_type, build_array_type, build_typedef_type)
	(build_var_decl, build_function_decl): Adjust for the new
	signature of build_ir_node_from_die.
	(build_translation_unit_and_add_to_ir): Likewise.  Perform the
	late canonicalizing of the types that have been scheduled for
	that.
	(build_class_type_and_add_to_ir): Return a class_decl_sptr, not a
	decl_base_sptr.  Adjust for the new signature of
	build_ir_node_from_die.  Early canonicalize member types that are
	created and added to a given class, or schedule them for late
	canonicalizing.
	* src/abg-reader.cc (class read_context::{m_wip_classes_map,
	m_types_to_canonicalize}): New data members.
	(read_context::{clear_types_to_canonicalize,
	clear_wip_classes_map, mark_class_as_wip, unmark_class_as_wip,
	is_wip_class, maybe_canonicalize_type,
	schedule_type_for_late_canonicalizing,
	perform_late_type_canonicalizing}): Add new method definitions.
	(read_context::clear_per_translation_unit_data): Call
	read_context::clear_types_to_canonicalize().
	(read_translation_unit_from_input): Call
	read_context::perform_late_type_canonicalizing() at the end of the
	function.
	(build_function_decl): Fix the function type canonicalizing (per
	translation) that was already in place.  Do the canonicalizing of
	these only when the type is fully built.  Oops.  This was really
	brokend.  Also, when the function type is constructed, consider it
	for type canonicalizing.
	(build_type_decl): Early canonicalize basic types.
	(build_qualified_type_decl, build_pointer_type_def)
	(build_pointer_type_def, build_reference_type_def)
	(build_array_type_def, build_enum_type_decl, build_typedef_decl):
	Handle the canonicalizing for these composite types: either early
	or late.
	(build_class_decl): Likewise.  Also, mark this class a 'being
	built' until it's fully built.  This helps the canonicalizing code
	to know that it should leave a class alone until it's fully built.
	* tests/test-ir-walker.cc (struct name_printing_visitor): Adjust
	to the visitor methods naming change.
	* configure.ac: Generate the tests/runtestcanonicalizetypes.sh
	testing script from tests/runtestcanonicalizetypes.sh.in.
	* tests/runtestcanonicalizetypes.sh.in: Add the template for the
	new runtestcanonicalizetypes.sh script that test for type
	canonicalizing.
	* tests/Makefile.am: Add the new runtestcanonicalizetypes.sh
	regression testing script to the build system.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>
2015-02-18 21:32:37 +01:00

98 lines
3.0 KiB
C++

// -*- mode: C++ -*-
//
// Copyright (C) 2013-2015 Red Hat, Inc.
//
// This file is part of the GNU Application Binary Interface Generic
// Analysis and Instrumentation Library (libabigail). This library is
// free software; you can redistribute it and/or modify it under the
// terms of the GNU Lesser General Public License as published by the
// Free Software Foundation; either version 3, or (at your option) any
// later version.
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Lesser Public License for more details.
// You should have received a copy of the GNU Lesser General Public
// License along with this program; see the file COPYING-LGPLV3. If
// not, see <http://www.gnu.org/licenses/>.
/// @file
#ifndef __ABG_TRAVERSE_H__
#define __ABG_TRAVERSE_H__
#include "abg-fwd.h"
namespace abigail
{
namespace ir
{
/// The base class for the visitor type hierarchy used for traversing
/// a hierarchy of nodes.
///
/// Client code willing to get notified for a certain kind of node
/// during traversal might want to define a visitor class that inherit
/// \a node_visitor, define and overload a node_visitor::visit method
/// for it, like what is done for the ir_node_visitor::visit set of
/// functions, for traversing internal representation nodes.
struct node_visitor_base
{};
/// The interface for types which are feeling social and want to be
/// visited during the traversal of a hierarchy of nodes.
class traversable_base
{
bool visiting_;
protected:
/// This should returns false before and after the node has been
/// visiting. During the visiting of the node (and of its children)
/// this should return true.
///
/// @return true if the current node is being visited.
bool
visiting()
{return visiting_;}
/// The traversing code should be responsible of calling this, not
/// the user code.
///
/// This is the setter of the "visiting" flag of the node being
/// visited. If set to yes, it means the node is being visited.
/// False means either the node has not yet been visited, or it
/// has already been visited.
///
/// @param f the new value of the "visiting" flag.
void
visiting(bool f)
{visiting_ = f;}
public:
traversable_base()
: visiting_()
{}
/// This virtual method is overloaded and implemented by any single
/// type which instance is going to be visited during the traversal
/// of translation unit nodes.
///
/// The method visits a given node and, for scopes, visits their
/// member nodes. Visiting a node means calling the
/// ir_node_visitor::visit method with the node passed as an
/// argument.
///
/// @param v the visitor used during the traverse.
///
/// @return true if traversed until the end of the type tree, false
/// otherwise.
virtual bool traverse(node_visitor_base& v);
};
}// end namespace ir.
}//end namespace abigail
#endif //__ABG_TRAVERSE_H__