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/* Copyright (C) 2007-2010 The Android Open Source Project
**
** This software is licensed under the terms of the GNU General Public
** License version 2, as published by the Free Software Foundation, and
** may be copied, distributed, and modified under those terms.
**
** This program 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 Public License for more details.
*/
/*
* Contains declarations of classes defined for a variety of DWARF objects.
*/
#ifndef ELFF_DWARF_DIE_H_
#define ELFF_DWARF_DIE_H_
#include "dwarf_defs.h"
#include "elf_alloc.h"
class ElfFile;
class DwarfCU;
/* Encapsulates an object that wraps up a DIE, cached during
* ELF file parsing.
*/
class DIEObject : public DwarfAllocBase {
public:
/* Constructs DIEObject intance.
* Param:
* die - DIE represented with this instance.
* parent_cu - Compilation unit this DIE belongs to.
* parent_die - Parent DIE object for this DIE. This parameter can be NULL
* only for compilation unit DIEs.
*/
DIEObject(const Dwarf_DIE* die, DwarfCU* parent_cu, DIEObject* parent_die)
: die_(die),
parent_cu_(parent_cu),
parent_die_(parent_die),
last_child_(NULL),
prev_sibling_(NULL) {
}
/* Destructs DIEObject intance. */
~DIEObject();
/* Gets ELF file this DIE belongs to. */
ElfFile* elf_file() const;
/* Gets DWARF tag (DW_TAG_Xxx) for the DIE represented with this instance. */
Dwarf_Tag get_tag() const;
/* Gets the best name for this DIE.
* Some DIEs (such as inline routine DIEs) may have no DW_AT_name property,
* but may reference to another DIE that may contain DIE name. This method
* tries its best to get DIE name by iterating through different methods of
* naming the DIE.
* Return:
* Name for this DIE, or NULL if it was not possible to find a relevant DIE
* with DW_AT_name property.
*/
const char* get_name() const;
/* Gets DIE's attribute by its ID.
* Param:
* at_id - ID (DW_AT_Xxx) of the attribute to get.
* attr - Upon successful return contains requested attribute information.
* Return:
* true on success, or false if attribute for the given ID doesn't exist
* in the DIE's attribute list.
*/
bool get_attrib(Dwarf_At at, DIEAttrib* attr) const;
/* Gets the leaf DIE object containing given address.
* See DwarfCU::get_leaf_die_for_address() for method details.
* See DIEObject::contains_address() for implementation details.
*/
DIEObject* get_leaf_for_address(Elf_Xword address);
/* Finds a DIE object for the given die in the branch starting with
* this DIE object.
*/
DIEObject* find_die_object(const Dwarf_DIE* die_to_find);
/* Dumps this object to stdout.
* Param:
* only_this - If true, only this object will be dumped. If this parameter
* is false, all the childs and siblings of this object will be dumped
* along with this object.
*/
void dump(bool only_this) const;
protected:
/* Checks if this DIE object containing given address.
* Template param:
* AddrType - Type of compilation unin address (4, or 8 bytes), defined by
* address_size field of the CU header. Must be Elf_Xword for 8 bytes
* address, or Elf_Word for 4 bytes address.
* Param:
* address - Address ti check.
* Return:
* True, if this DIE address ranges (including low_pc, high_pc attributes)
* contain given address, or false otherwise.
*/
template <typename AddrType>
bool contains_address(Elf_Xword address);
/* Advances to the DIE's property list.
* Param:
* at_abbr - Upon successful return contains a pointer to the beginning of
* DIE attribute abbreviation list. This parameter can be NULL, if the
* caller is not interested in attribute abbreviation list for this DIE.
* tag - Upon successful return contains DIE's tag. This parameter can be
* NULL, if the caller is not interested in the tag value for this DIE.
* Return:
* Pointer to the beginning of the DIE attribute list in mapped .debug_info
* section on success, or NULL on failure.
*/
const Elf_Byte* advance(const Dwarf_Abbr_AT** at_abbr, Dwarf_Tag* tag) const;
public:
/* Gets DIE represented with this instance. */
const Dwarf_DIE* die() const {
return die_;
}
/* Gets compilation unit this DIE belongs to. */
DwarfCU* parent_cu() const {
return parent_cu_;
}
/* Gets parent DIE object for this die. */
DIEObject* parent_die() const {
return parent_die_;
}
/* Gets last child object in the list of this DIE's childs. NOTE: for better
* performace the list is created in reverse order (relatively to the order,
* in which children DIEs have been discovered).
*/
DIEObject* last_child() const {
return last_child_;
}
/* Links next child to the list of this DIE childs. */
void link_child(DIEObject* child) {
last_child_ = child;
}
/* Gets previous sibling of this DIE in the parent's DIE object list. */
DIEObject* prev_sibling() const {
return prev_sibling_;
}
/* Links next sibling to the list of this DIE siblings. */
void link_sibling(DIEObject* sibl) {
prev_sibling_ = sibl;
}
/* Checks if this DIE object represents a CU DIE.
* We relay here on the fact that only CU DIE objects have no parent
* DIE objects.
*/
bool is_cu_die() const {
return parent_die_ == NULL;
}
/* Gets this DIE level in the branch.
* DIE level defines DIE's distance from the CU DIE in the branch this DIE
* belongs to. In other words, DIE level defines how many parent DIEs exist
* between this DIE, and the CU DIE. For instance, the CU DIE has level 0,
* a subroutine a() in this compilation unit has level 1, a soubroutine b(),
* that has been inlined into subroutine a() will have level 2, a try/catch
* block in the inlined subroutine b() will have level 3, and so on.
*/
Elf_Word get_level() const {
return parent_die_ != NULL ? parent_die_->get_level() + 1 : 0;
}
protected:
/* DIE that is represented with this instance. */
const Dwarf_DIE* die_;
/* Compilation unit this DIE belongs to. */
DwarfCU* parent_cu_;
/* Parent DIE object for this die. */
DIEObject* parent_die_;
/* Last child object in the list of this DIE's childs. NOTE: for better
* performace the list is created in reverse order (relatively to the order,
* in which children DIEs have been discovered).
*/
DIEObject* last_child_;
/* Previous sibling of this DIE in the parent's DIE object list. */
DIEObject* prev_sibling_;
};
#endif // ELFF_DWARF_DIE_H_
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