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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 declaration of a class DwarfCU, that encapsulates a compilation
* unit in the .debug_info section of the mapped ELF file.
*/
#ifndef ELFF_DWARF_CU_H_
#define ELFF_DWARF_CU_H_
#include "dwarf_defs.h"
#include "dwarf_die.h"
/* Address information descriptor. */
typedef struct Dwarf_AddressInfo {
/* Routine DIE containing the address. */
const DIEObject* die_obj;
/* Source file name for the address. */
const char* file_name;
/* Source file directory path for the address. */
const char* dir_name;
/* Source file line number for the address. */
Elf_Word line_number;
} Dwarf_AddressInfo;
/* STMTL header cached by compilation unit. This header is contained in
* the .debug_line section of the ELF file. */
typedef struct Dwarf_STMTL_Hdr {
/* The size in bytes of the line number information for this compilation
* unit, not including the unit_length field itself. */
Elf_Xword unit_length;
/* A version number. This number is specific to the line number information
* and is independent of the DWARF version number. */
Elf_Half version;
/* The number of bytes following the header_length field to the beginning of
* the first byte of the line number program itself. In the 32-bit DWARF
* format, this is a 4-byte unsigned length; in the 64-bit DWARF format,
* this field is an 8-byte unsigned length. */
Elf_Xword header_length;
/* The size in bytes of the smallest target machine instruction. Line number
* program opcodes that alter the address register first multiply their
* operands by this value. */
Elf_Byte min_instruction_len;
/* The initial value of the is_stmt register. */
Elf_Byte default_is_stmt;
/* This parameter affects the meaning of the special opcodes. */
Elf_Sbyte line_base;
/* This parameter affects the meaning of the special opcodes. */
Elf_Byte line_range;
/* The number assigned to the first special opcode. */
Elf_Byte opcode_base;
/* Points to standard_opcode_lengths array in the actual STMTL header in
* the mapped .debug_line section. */
const Elf_Byte* standard_opcode_lengths;
/* Pointer to the beginning of the list of include directories in the mapped
* .debug_line section. */
const char* include_directories;
/* Number of include directories in the list that begins with
* include_directories. */
Elf_Word inc_dir_num;
/* Pointer to the beginning of the list of file information in the mapped
* .debug_line section. Each entry in this list begins with zero-terminated
* file name, followed by ULEB128 encoding directory index for the file,
* followed by ULEB128 encoding last modification time, followed by ULEB128
* encoding length of file in bytes. */
const Dwarf_STMTL_FileDesc* file_infos;
/* Start of the "Line Number Program" in the mapped .debug_line section. */
const Elf_Byte* start;
/* End of the "Line Number Program" in the mapped .debug_line section. */
const Elf_Byte* end;
} Dwarf_STMTL_Hdr;
/* Encapsulates architecture-independent functionality of a
* compilation unit.
*/
class DwarfCU : public DwarfAllocBase {
friend class ElfFile;
public:
/* Constructs DwarfCU instance.
* Param:
* elf - Instance of ElfFile containing this compilation unit.
*/
explicit DwarfCU(ElfFile* elf);
/* Destructs DwarfCU instance. */
virtual ~DwarfCU();
/* Creates DwarfCUImpl instance, depending on DWARF format.
* Param:
* elf - Instance of ElfFile containing this compilation unit.
* hdr - Pointer to compilation unit header inside mapped .debug_info
* section of the ELF file. Actual data addressed by this pointer
* must be Dwarf32_CUHdr for 32 bit DWARFs, or Dwarf64_CUHdr for
* 64 bit DWARFs.
* Return:
* Created DwarfCUImpl instance (typecasted back to DwarfCU) on success,
* or NULL on failure.
*/
static DwarfCU* create_instance(ElfFile* elf, const void* hdr);
/* Process a DIE attribute.
* Param:
* attr - Attribute list inside the mapped .debug_info section of the ELF
* file.
* form - Attribute's form, definig representation of attribute value in the
* mapped .debug_info section of the ELF file.
* attr_value - Upon return contains attribute value.
* Return:
* Pointer to the next DIE attribute inside the mapped .debug_info section
* of the ELF file.
*/
const Elf_Byte* process_attrib(const Elf_Byte* attr,
Dwarf_Form form,
Dwarf_Value* attr_value) const;
/* Dumps this compilation unit to the stdout. */
void dump() const;
/* Gets instance of ElfFile containing this compilation unit. */
ElfFile* elf_file() const {
return elf_file_;
}
/* Gets DIE object for this CU. */
DIEObject* cu_die() const {
return cu_die_;
}
/* Gets byte size of the pointer type for this compilation unit. */
Elf_Byte addr_sizeof() const {
return addr_sizeof_;
}
/* Gets full path to the compilation directory (DW_AT_comp_dir attribute).
* Return:
* Full path to the compilation directory (DW_AT_comp_dir attribute),
* or NULL, if that attribute was missing in CU's attribute list.
*/
const char* comp_dir_path() const {
DIEAttrib attr;
return cu_die()->get_attrib(DW_AT_comp_dir, &attr) ? attr.value()->str :
NULL;
}
/* Gets relative (from the compilation directory) path to the compiled file.
* (DW_AT_name attribute).
* Return:
* Relative path to the compiled file (DW_AT_name attribute), or NULL, if
* that attribute was missing in CU's attribute list.
*/
const char* rel_cu_path() const {
DIEAttrib attr;
return cu_die()->get_attrib(DW_AT_name, &attr) ? attr.value()->str :
NULL;
}
/* Gets next compilation unit in the list. NULL indicates the last CU. */
DwarfCU* prev_cu() const {
return prev_cu_;
}
/* Links this CU to the list of prevoiusly discovered CUs. */
void set_prev_cu(DwarfCU* prev) {
prev_cu_ = prev;
}
/* Checks if DWARF version for this CU is higher than 2. */
bool is_DWARF3_or_higher() const {
return version_ >= 3;
}
/* Gets DIE abbreviation for given abbreviation number.
* See DwarfAbbrDieArray::get() */
const Dwarf_Abbr_DIE* get_die_abbr(Dwarf_AbbrNum num) const {
return abbrs_.get(num);
}
/* Gets DIE object containing given address.
* DIE address ranges may overlap (for instance, address range for an inlined
* routine will be contained within the address range of a routine where it
* was inlined). This method will return a DIE object that is a "leaf" in
* that inlining tree. I.e the returned DIE object represents the last DIE
* in the branch of all DIEs containing given address.
* Param:
* address - Address to get a DIE for. NOTE: for the sake of simplicity we
* explicitly use 64-bit type for an address.
* Return:
* Leaf DIE containing given address, or NULL if this CU doesn't contain
* the given address.
*/
DIEObject* get_leaf_die_for_address(Elf_Xword address) const {
return cu_die_->get_leaf_for_address(address);
}
/* Checks if this CU contains 64, or 32-bit addresses. */
bool is_CU_address_64() const {
return addr_sizeof_ == 8;
}
bool is_CU_address_32() const {
return addr_sizeof_ == 4;
}
//=============================================================================
// DWARF format dependent methods
//=============================================================================
public:
/* Parses this compilation unit in .debug_info section, collecting children
* DIEs of this compilation unit.
* Param:
* parse_context - Parsing context that lists tags for DIEs that should be
* collected during parsing. NULL passed in this parameter indicates DIEs
* for all tags should be collected.
* next_cu_die - Upon successful return contains pointer to the next
* compilation unit descriptor inside mapped .debug_info section of
* the ELF file.
* Return:
* true on success, false on failure.
*/
virtual bool parse(const DwarfParseContext* parse_context,
const void** next_cu_die) = 0;
/* Gets a DIE object referenced by an offset from the beginning of
* this CU in the mapped .debug_info section.
*/
virtual DIEObject* get_referenced_die_object(Elf_Word ref) const = 0;
/* Gets a reference to a DIE object (offset of the DIE from the
* beginning of this CU in the mapped .debug_info section.
*/
virtual Elf_Word get_die_reference(const Dwarf_DIE* die) const = 0;
/* Gets PC address information.
* Param:
* address - PC address to get information for.
* info - Upon success contains information about routine that belongs to
* this compilation unit, containing the given address.
* Return:
* true on success, or false if this CU doesn't contain the given address.
*/
virtual bool get_pc_address_file_info(Elf_Xword address,
Dwarf_AddressInfo* info) = 0;
/* Gets file descriptor in the mapped .debug_line section of ELF file for a
* given index in the file descriptor list.
* Param:
* index - 1-based index of file descriptor in the file descriptor list.
* Return:
* File descriptor for the given index, or NULL if index was too big.
* NOTE: pointer returned from this method addressed mapped section of
* ELF file.
*/
virtual const Dwarf_STMTL_FileDesc* get_stmt_file_info(Elf_Word index) = 0;
/* Gets directory name by an index in the mapped .debug_line section of
* ELF file.
* Param:
* dir_index - Index of the directory in the file descriptor list. If this
* parameter is zero, compilation directory (DW_AT_comp_dir) for this CU
* will be returned.
* Return:
* Directory name for the given index, or NULL if index was too big.
* NOTE: pointer returned from this method addressed mapped section of
* ELF file.
*/
virtual const char* get_stmt_dir_name(Elf_Word dir_index) = 0;
protected:
/* DIE abbreviation descriptors, cached for this compilation unit. */
DwarfAbbrDieArray abbrs_;
/* Instance of an ELF file that contains this compilation unit. */
ElfFile* elf_file_;
/* DIE object for this CU. */
DIEObject* cu_die_;
/* Next compilation unit in the list (previous in the order they've been
* discovered during ELF file parsing).
*/
DwarfCU* prev_cu_;
/* DWARF version for this CU. */
Elf_Half version_;
/* Byte size of the pointer type for this compilation unit. */
Elf_Byte addr_sizeof_;
};
/* Encapsulates architecture-dependent functionality of a compilation unit.
* Template param:
* Dwarf_CUHdr - type compilation unit header in the mapped .debug_info
* section of ELF file. Must be:
* - Dwarf32_CUHdr for 32-bit DWARF, or
* - Dwarf64_CUHdr for 64-bit DWARF.
* Dwarf_Off - type for an offset field in DWARF data format. Must be:
* - Dwarf32_Off for 32-bit DWARF, or
* - Dwarf64_Off for 64-bit DWARF.
*/
template <typename Dwarf_CUHdr, typename Dwarf_Off>
class DwarfCUImpl : public DwarfCU {
public:
/* Constructs DwarfCU instance.
* Param:
* elf - Instance of ElfFile containing this compilation unit.
* hdr - Pointer to compilation unit header inside mapped .debug_info
* section of the ELF file.
*/
DwarfCUImpl(ElfFile* elf, const Dwarf_CUHdr* hdr);
/* Destructs DwarfCU instance. */
~DwarfCUImpl() {
}
/* Parses this compilation unit in .debug_info section, collecting children
* DIEs of this compilation unit. This is an implementation of DwarfCU's
* abstract metod.
* See DwarfCU::parse().
*/
bool parse(const DwarfParseContext* parse_context,
const void** next_cu_die);
/* Gets PC address information.
* This is an implementation of DwarfCU's abstract metod.
* See DwarfCU::get_pc_address_file_info().
*/
bool get_pc_address_file_info(Elf_Xword address, Dwarf_AddressInfo* info);
/* Gets file descriptor in the mapped .debug_line section of ELF file for a
* given index in the file descriptor list.
* This is an implementation of DwarfCU's abstract metod.
* See DwarfCU::get_stmt_file_info().
*/
const Dwarf_STMTL_FileDesc* get_stmt_file_info(Elf_Word index);
/* Gets directory name by an index in the mapped .debug_line section of
* ELF file.
* This is an implementation of DwarfCU's abstract metod.
* See DwarfCU::get_stmt_dir_name().
*/
const char* get_stmt_dir_name(Elf_Word dir_index);
/* Gets a DIE object referenced by an offset from the beginning of
* this CU. This is an implementation of DwarfCU's abstract metod.
*/
DIEObject* get_referenced_die_object(Elf_Word ref) const {
const Dwarf_DIE* die = get_referenced_die(ref);
return cu_die_->find_die_object(die);
}
/* Gets a reference to a DIE object (offset of the DIE from the
* beginning of this CU in the mapped .debug_info section.
* This is an implementation of DwarfCU's abstract metod.
*/
Elf_Word get_die_reference(const Dwarf_DIE* die) const {
return static_cast<Elf_Word>(diff_ptr(cu_header_, die));
}
protected:
/* Process a child DIE (and all its children) in this compilation unit.
* Param:
* parse_context - See DwarfCU::parse().
* die - DIE descriptor of the child to process in this method.
* parent_obj - Parent object of the child to process in this method.
* NOTE: this parameter can be NULL only for a DIE that represents this
* compilation unit itself.
* Return:
* Pointer to the end of child's attribute list in the mapped .debug_info
* section on success, or NULL on failure. Usually, pointer returned from
* this method is simply discarded, since parent calculates address of the
* next sibling's DIE based on DW_AT_sibling attribute of the DIE preceding
* child's DIE.
*/
const Elf_Byte* process_DIE(const DwarfParseContext* parse_context,
const Dwarf_DIE* die,
DIEObject* parent_obj);
/* Creates a DIE object for the given DIE.
* Param:
* parse_context See DwarfCU::parse().
* die - DIE to create an object for.
* parent - Parent DIE object for the one that's being created in this
* method.
* tag - Tag of the DIE object that's being created in this method.
* Return:
* Created DIE object. This method may returns NULL in two cases:
* - We're not interested in this DIE (decided by looking at 'tag'
* parameter. In this case errno should be set to zero.
* - Memory allocation has failed. In this case errno should be
* set to ENOMEM.
*/
DIEObject* create_die_object(const DwarfParseContext* parse_context,
const Dwarf_DIE* die,
DIEObject* parent,
Dwarf_Tag tag);
/* Initializes (caches) STMT lines header for this CU. */
bool init_stmtl();
/* Saves current source file information, collected in the state machine by
* the "Line Number Program".
* Param:
* state - State machine collected "Line Number Program" results.
* info - Upon success contains source file information, copied over from
* the state machine.
* Return:
* true on success, or false on failure.
*/
bool set_source_info(const DwarfStateMachine* state,
Dwarf_AddressInfo* info);
/* Gets pointer to the DIE descriptor for this CU. */
const Dwarf_DIE* get_DIE() const {
/* CU's DIE descriptor immediately follows CU header. */
return INC_CPTR_T(Dwarf_DIE, cu_header_, sizeof(Dwarf_CUHdr));
}
/* Caches STMTL header from .debug_line section to stmtl_header_.
* Template param:
* Dwarf_STMTL_Hdr - Dwarf_STMTL_Hdr32, or Dwarf_STMTL_Hdr64, depending
* on the header type.
* Param:
* stmtl_hdr - STMTL header in the mapped .debug_line section to cache.
*/
template <typename Dwarf_STMTL_Hdr>
void cache_stmtl(const Dwarf_STMTL_Hdr* stmtl_hdr) {
stmtl_header_.unit_length = elf_file()->pull_val(stmtl_hdr->unit_length.size);
stmtl_header_.version = elf_file()->pull_val(stmtl_hdr->version);
stmtl_header_.header_length = elf_file()->pull_val(stmtl_hdr->header_length);
stmtl_header_.min_instruction_len = stmtl_hdr->min_instruction_len;
stmtl_header_.default_is_stmt = stmtl_hdr->default_is_stmt;
stmtl_header_.line_base = stmtl_hdr->line_base;
stmtl_header_.line_range = stmtl_hdr->line_range;
stmtl_header_.opcode_base = stmtl_hdr->opcode_base;
stmtl_header_.standard_opcode_lengths = &stmtl_hdr->standard_opcode_lengths;
stmtl_header_.start = INC_CPTR_T(Elf_Byte, &stmtl_hdr->min_instruction_len,
stmtl_header_.header_length);
stmtl_header_.end = INC_CPTR_T(Elf_Byte, &stmtl_hdr->version,
stmtl_header_.unit_length);
stmtl_header_.include_directories =
INC_CPTR_T(char, stmtl_header_.standard_opcode_lengths,
stmtl_header_.opcode_base - 1);
const char* dir = stmtl_header_.include_directories;
while (*dir != '\0') {
dir += strlen(dir) + 1;
stmtl_header_.inc_dir_num++;
}
stmtl_header_.file_infos = INC_CPTR_T(Dwarf_STMTL_FileDesc, dir, 1);
}
/* Gets a DIE referenced by an offset from the beginning of this CU
* in the mapped .debug_info section.
*/
const Dwarf_DIE* get_referenced_die(Elf_Word ref) const {
return INC_CPTR_T(Dwarf_DIE, cu_header_, ref);
}
/* Checks if pointer to the DIE attribute is contained within the CU's area
* of the mapped .debug_info section.
* Param:
* ptr - Pointer to the DIE attribute to check.
* Return:
* true, if pointer to the DIE attribute is contained within the CU's area
* of the mapped .debug_info section, or false if attribute pointer goes
* beyond CU's area of the mapped .debug_info section.
*/
bool is_attrib_ptr_valid(const void* ptr) const {
return diff_ptr(cu_header_, ptr) < cu_size_;
}
protected:
/* Pointer to this compilation unit header inside the mapped .debug_info
* section of the ELF file.
*/
const Dwarf_CUHdr* cu_header_;
/* Size of this compilation unit area in the mapped .debug_info section.
* This value has been cached off the CU header in order to avoid
* endianness conversions.
*/
Dwarf_Off cu_size_;
/* STMT lines header, cached off mapped .debug_line section. */
Dwarf_STMTL_Hdr stmtl_header_;
};
#endif // ELFF_DWARF_CU_H_