blob: e6b1f238cd3db2f2d369911a3efe23a77a3f1326 [file] [log] [blame]
/* dwarf.c -- Get file/line information from DWARF for backtraces.
Copyright (C) 2012-2021 Free Software Foundation, Inc.
Written by Ian Lance Taylor, Google.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
(1) Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
(2) Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
(3) The name of the author may not be used to
endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE. */
#include "config.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include "dwarf2.h"
#include "filenames.h"
#include "backtrace.h"
#include "internal.h"
#if !defined(HAVE_DECL_STRNLEN) || !HAVE_DECL_STRNLEN
/* If strnlen is not declared, provide our own version. */
static size_t
xstrnlen (const char *s, size_t maxlen)
{
size_t i;
for (i = 0; i < maxlen; ++i)
if (s[i] == '\0')
break;
return i;
}
#define strnlen xstrnlen
#endif
/* A buffer to read DWARF info. */
struct dwarf_buf
{
/* Buffer name for error messages. */
const char *name;
/* Start of the buffer. */
const unsigned char *start;
/* Next byte to read. */
const unsigned char *buf;
/* The number of bytes remaining. */
size_t left;
/* Whether the data is big-endian. */
int is_bigendian;
/* Error callback routine. */
backtrace_error_callback error_callback;
/* Data for error_callback. */
void *data;
/* Non-zero if we've reported an underflow error. */
int reported_underflow;
};
/* A single attribute in a DWARF abbreviation. */
struct attr
{
/* The attribute name. */
enum dwarf_attribute name;
/* The attribute form. */
enum dwarf_form form;
/* The attribute value, for DW_FORM_implicit_const. */
int64_t val;
};
/* A single DWARF abbreviation. */
struct abbrev
{
/* The abbrev code--the number used to refer to the abbrev. */
uint64_t code;
/* The entry tag. */
enum dwarf_tag tag;
/* Non-zero if this abbrev has child entries. */
int has_children;
/* The number of attributes. */
size_t num_attrs;
/* The attributes. */
struct attr *attrs;
};
/* The DWARF abbreviations for a compilation unit. This structure
only exists while reading the compilation unit. Most DWARF readers
seem to a hash table to map abbrev ID's to abbrev entries.
However, we primarily care about GCC, and GCC simply issues ID's in
numerical order starting at 1. So we simply keep a sorted vector,
and try to just look up the code. */
struct abbrevs
{
/* The number of abbrevs in the vector. */
size_t num_abbrevs;
/* The abbrevs, sorted by the code field. */
struct abbrev *abbrevs;
};
/* The different kinds of attribute values. */
enum attr_val_encoding
{
/* No attribute value. */
ATTR_VAL_NONE,
/* An address. */
ATTR_VAL_ADDRESS,
/* An index into the .debug_addr section, whose value is relative to
* the DW_AT_addr_base attribute of the compilation unit. */
ATTR_VAL_ADDRESS_INDEX,
/* A unsigned integer. */
ATTR_VAL_UINT,
/* A sigd integer. */
ATTR_VAL_SINT,
/* A string. */
ATTR_VAL_STRING,
/* An index into the .debug_str_offsets section. */
ATTR_VAL_STRING_INDEX,
/* An offset to other data in the containing unit. */
ATTR_VAL_REF_UNIT,
/* An offset to other data within the .debug_info section. */
ATTR_VAL_REF_INFO,
/* An offset to other data within the alt .debug_info section. */
ATTR_VAL_REF_ALT_INFO,
/* An offset to data in some other section. */
ATTR_VAL_REF_SECTION,
/* A type signature. */
ATTR_VAL_REF_TYPE,
/* An index into the .debug_rnglists section. */
ATTR_VAL_RNGLISTS_INDEX,
/* A block of data (not represented). */
ATTR_VAL_BLOCK,
/* An expression (not represented). */
ATTR_VAL_EXPR,
};
/* An attribute value. */
struct attr_val
{
/* How the value is stored in the field u. */
enum attr_val_encoding encoding;
union
{
/* ATTR_VAL_ADDRESS*, ATTR_VAL_UINT, ATTR_VAL_REF*. */
uint64_t uint;
/* ATTR_VAL_SINT. */
int64_t sint;
/* ATTR_VAL_STRING. */
const char *string;
/* ATTR_VAL_BLOCK not stored. */
} u;
};
/* The line number program header. */
struct line_header
{
/* The version of the line number information. */
int version;
/* Address size. */
int addrsize;
/* The minimum instruction length. */
unsigned int min_insn_len;
/* The maximum number of ops per instruction. */
unsigned int max_ops_per_insn;
/* The line base for special opcodes. */
int line_base;
/* The line range for special opcodes. */
unsigned int line_range;
/* The opcode base--the first special opcode. */
unsigned int opcode_base;
/* Opcode lengths, indexed by opcode - 1. */
const unsigned char *opcode_lengths;
/* The number of directory entries. */
size_t dirs_count;
/* The directory entries. */
const char **dirs;
/* The number of filenames. */
size_t filenames_count;
/* The filenames. */
const char **filenames;
};
/* A format description from a line header. */
struct line_header_format
{
int lnct; /* LNCT code. */
enum dwarf_form form; /* Form of entry data. */
};
/* Map a single PC value to a file/line. We will keep a vector of
these sorted by PC value. Each file/line will be correct from the
PC up to the PC of the next entry if there is one. We allocate one
extra entry at the end so that we can use bsearch. */
struct line
{
/* PC. */
uintptr_t pc;
/* File name. Many entries in the array are expected to point to
the same file name. */
const char *filename;
/* Line number. */
int lineno;
/* Index of the object in the original array read from the DWARF
section, before it has been sorted. The index makes it possible
to use Quicksort and maintain stability. */
int idx;
};
/* A growable vector of line number information. This is used while
reading the line numbers. */
struct line_vector
{
/* Memory. This is an array of struct line. */
struct backtrace_vector vec;
/* Number of valid mappings. */
size_t count;
};
/* A function described in the debug info. */
struct function
{
/* The name of the function. */
const char *name;
/* If this is an inlined function, the filename of the call
site. */
const char *caller_filename;
/* If this is an inlined function, the line number of the call
site. */
int caller_lineno;
/* Map PC ranges to inlined functions. */
struct function_addrs *function_addrs;
size_t function_addrs_count;
};
/* An address range for a function. This maps a PC value to a
specific function. */
struct function_addrs
{
/* Range is LOW <= PC < HIGH. */
uint64_t low;
uint64_t high;
/* Function for this address range. */
struct function *function;
};
/* A growable vector of function address ranges. */
struct function_vector
{
/* Memory. This is an array of struct function_addrs. */
struct backtrace_vector vec;
/* Number of address ranges present. */
size_t count;
};
/* A DWARF compilation unit. This only holds the information we need
to map a PC to a file and line. */
struct unit
{
/* The first entry for this compilation unit. */
const unsigned char *unit_data;
/* The length of the data for this compilation unit. */
size_t unit_data_len;
/* The offset of UNIT_DATA from the start of the information for
this compilation unit. */
size_t unit_data_offset;
/* Offset of the start of the compilation unit from the start of the
.debug_info section. */
size_t low_offset;
/* Offset of the end of the compilation unit from the start of the
.debug_info section. */
size_t high_offset;
/* DWARF version. */
int version;
/* Whether unit is DWARF64. */
int is_dwarf64;
/* Address size. */
int addrsize;
/* Offset into line number information. */
off_t lineoff;
/* Offset of compilation unit in .debug_str_offsets. */
uint64_t str_offsets_base;
/* Offset of compilation unit in .debug_addr. */
uint64_t addr_base;
/* Offset of compilation unit in .debug_rnglists. */
uint64_t rnglists_base;
/* Primary source file. */
const char *filename;
/* Compilation command working directory. */
const char *comp_dir;
/* Absolute file name, only set if needed. */
const char *abs_filename;
/* The abbreviations for this unit. */
struct abbrevs abbrevs;
/* The fields above this point are read in during initialization and
may be accessed freely. The fields below this point are read in
as needed, and therefore require care, as different threads may
try to initialize them simultaneously. */
/* PC to line number mapping. This is NULL if the values have not
been read. This is (struct line *) -1 if there was an error
reading the values. */
struct line *lines;
/* Number of entries in lines. */
size_t lines_count;
/* PC ranges to function. */
struct function_addrs *function_addrs;
size_t function_addrs_count;
};
/* An address range for a compilation unit. This maps a PC value to a
specific compilation unit. Note that we invert the representation
in DWARF: instead of listing the units and attaching a list of
ranges, we list the ranges and have each one point to the unit.
This lets us do a binary search to find the unit. */
struct unit_addrs
{
/* Range is LOW <= PC < HIGH. */
uint64_t low;
uint64_t high;
/* Compilation unit for this address range. */
struct unit *u;
};
/* A growable vector of compilation unit address ranges. */
struct unit_addrs_vector
{
/* Memory. This is an array of struct unit_addrs. */
struct backtrace_vector vec;
/* Number of address ranges present. */
size_t count;
};
/* A growable vector of compilation unit pointer. */
struct unit_vector
{
struct backtrace_vector vec;
size_t count;
};
/* The information we need to map a PC to a file and line. */
struct dwarf_data
{
/* The data for the next file we know about. */
struct dwarf_data *next;
/* The data for .gnu_debugaltlink. */
struct dwarf_data *altlink;
/* The base address for this file. */
uintptr_t base_address;
/* A sorted list of address ranges. */
struct unit_addrs *addrs;
/* Number of address ranges in list. */
size_t addrs_count;
/* A sorted list of units. */
struct unit **units;
/* Number of units in the list. */
size_t units_count;
/* The unparsed DWARF debug data. */
struct dwarf_sections dwarf_sections;
/* Whether the data is big-endian or not. */
int is_bigendian;
/* A vector used for function addresses. We keep this here so that
we can grow the vector as we read more functions. */
struct function_vector fvec;
};
/* Report an error for a DWARF buffer. */
static void
dwarf_buf_error (struct dwarf_buf *buf, const char *msg, int errnum)
{
char b[200];
snprintf (b, sizeof b, "%s in %s at %d",
msg, buf->name, (int) (buf->buf - buf->start));
buf->error_callback (buf->data, b, errnum);
}
/* Require at least COUNT bytes in BUF. Return 1 if all is well, 0 on
error. */
static int
require (struct dwarf_buf *buf, size_t count)
{
if (buf->left >= count)
return 1;
if (!buf->reported_underflow)
{
dwarf_buf_error (buf, "DWARF underflow", 0);
buf->reported_underflow = 1;
}
return 0;
}
/* Advance COUNT bytes in BUF. Return 1 if all is well, 0 on
error. */
static int
advance (struct dwarf_buf *buf, size_t count)
{
if (!require (buf, count))
return 0;
buf->buf += count;
buf->left -= count;
return 1;
}
/* Read one zero-terminated string from BUF and advance past the string. */
static const char *
read_string (struct dwarf_buf *buf)
{
const char *p = (const char *)buf->buf;
size_t len = strnlen (p, buf->left);
/* - If len == left, we ran out of buffer before finding the zero terminator.
Generate an error by advancing len + 1.
- If len < left, advance by len + 1 to skip past the zero terminator. */
size_t count = len + 1;
if (!advance (buf, count))
return NULL;
return p;
}
/* Read one byte from BUF and advance 1 byte. */
static unsigned char
read_byte (struct dwarf_buf *buf)
{
const unsigned char *p = buf->buf;
if (!advance (buf, 1))
return 0;
return p[0];
}
/* Read a signed char from BUF and advance 1 byte. */
static signed char
read_sbyte (struct dwarf_buf *buf)
{
const unsigned char *p = buf->buf;
if (!advance (buf, 1))
return 0;
return (*p ^ 0x80) - 0x80;
}
/* Read a uint16 from BUF and advance 2 bytes. */
static uint16_t
read_uint16 (struct dwarf_buf *buf)
{
const unsigned char *p = buf->buf;
if (!advance (buf, 2))
return 0;
if (buf->is_bigendian)
return ((uint16_t) p[0] << 8) | (uint16_t) p[1];
else
return ((uint16_t) p[1] << 8) | (uint16_t) p[0];
}
/* Read a 24 bit value from BUF and advance 3 bytes. */
static uint32_t
read_uint24 (struct dwarf_buf *buf)
{
const unsigned char *p = buf->buf;
if (!advance (buf, 3))
return 0;
if (buf->is_bigendian)
return (((uint32_t) p[0] << 16) | ((uint32_t) p[1] << 8)
| (uint32_t) p[2]);
else
return (((uint32_t) p[2] << 16) | ((uint32_t) p[1] << 8)
| (uint32_t) p[0]);
}
/* Read a uint32 from BUF and advance 4 bytes. */
static uint32_t
read_uint32 (struct dwarf_buf *buf)
{
const unsigned char *p = buf->buf;
if (!advance (buf, 4))
return 0;
if (buf->is_bigendian)
return (((uint32_t) p[0] << 24) | ((uint32_t) p[1] << 16)
| ((uint32_t) p[2] << 8) | (uint32_t) p[3]);
else
return (((uint32_t) p[3] << 24) | ((uint32_t) p[2] << 16)
| ((uint32_t) p[1] << 8) | (uint32_t) p[0]);
}
/* Read a uint64 from BUF and advance 8 bytes. */
static uint64_t
read_uint64 (struct dwarf_buf *buf)
{
const unsigned char *p = buf->buf;
if (!advance (buf, 8))
return 0;
if (buf->is_bigendian)
return (((uint64_t) p[0] << 56) | ((uint64_t) p[1] << 48)
| ((uint64_t) p[2] << 40) | ((uint64_t) p[3] << 32)
| ((uint64_t) p[4] << 24) | ((uint64_t) p[5] << 16)
| ((uint64_t) p[6] << 8) | (uint64_t) p[7]);
else
return (((uint64_t) p[7] << 56) | ((uint64_t) p[6] << 48)
| ((uint64_t) p[5] << 40) | ((uint64_t) p[4] << 32)
| ((uint64_t) p[3] << 24) | ((uint64_t) p[2] << 16)
| ((uint64_t) p[1] << 8) | (uint64_t) p[0]);
}
/* Read an offset from BUF and advance the appropriate number of
bytes. */
static uint64_t
read_offset (struct dwarf_buf *buf, int is_dwarf64)
{
if (is_dwarf64)
return read_uint64 (buf);
else
return read_uint32 (buf);
}
/* Read an address from BUF and advance the appropriate number of
bytes. */
static uint64_t
read_address (struct dwarf_buf *buf, int addrsize)
{
switch (addrsize)
{
case 1:
return read_byte (buf);
case 2:
return read_uint16 (buf);
case 4:
return read_uint32 (buf);
case 8:
return read_uint64 (buf);
default:
dwarf_buf_error (buf, "unrecognized address size", 0);
return 0;
}
}
/* Return whether a value is the highest possible address, given the
address size. */
static int
is_highest_address (uint64_t address, int addrsize)
{
switch (addrsize)
{
case 1:
return address == (unsigned char) -1;
case 2:
return address == (uint16_t) -1;
case 4:
return address == (uint32_t) -1;
case 8:
return address == (uint64_t) -1;
default:
return 0;
}
}
/* Read an unsigned LEB128 number. */
static uint64_t
read_uleb128 (struct dwarf_buf *buf)
{
uint64_t ret;
unsigned int shift;
int overflow;
unsigned char b;
ret = 0;
shift = 0;
overflow = 0;
do
{
const unsigned char *p;
p = buf->buf;
if (!advance (buf, 1))
return 0;
b = *p;
if (shift < 64)
ret |= ((uint64_t) (b & 0x7f)) << shift;
else if (!overflow)
{
dwarf_buf_error (buf, "LEB128 overflows uint64_t", 0);
overflow = 1;
}
shift += 7;
}
while ((b & 0x80) != 0);
return ret;
}
/* Read a signed LEB128 number. */
static int64_t
read_sleb128 (struct dwarf_buf *buf)
{
uint64_t val;
unsigned int shift;
int overflow;
unsigned char b;
val = 0;
shift = 0;
overflow = 0;
do
{
const unsigned char *p;
p = buf->buf;
if (!advance (buf, 1))
return 0;
b = *p;
if (shift < 64)
val |= ((uint64_t) (b & 0x7f)) << shift;
else if (!overflow)
{
dwarf_buf_error (buf, "signed LEB128 overflows uint64_t", 0);
overflow = 1;
}
shift += 7;
}
while ((b & 0x80) != 0);
if ((b & 0x40) != 0 && shift < 64)
val |= ((uint64_t) -1) << shift;
return (int64_t) val;
}
/* Return the length of an LEB128 number. */
static size_t
leb128_len (const unsigned char *p)
{
size_t ret;
ret = 1;
while ((*p & 0x80) != 0)
{
++p;
++ret;
}
return ret;
}
/* Read initial_length from BUF and advance the appropriate number of bytes. */
static uint64_t
read_initial_length (struct dwarf_buf *buf, int *is_dwarf64)
{
uint64_t len;
len = read_uint32 (buf);
if (len == 0xffffffff)
{
len = read_uint64 (buf);
*is_dwarf64 = 1;
}
else
*is_dwarf64 = 0;
return len;
}
/* Free an abbreviations structure. */
static void
free_abbrevs (struct backtrace_state *state, struct abbrevs *abbrevs,
backtrace_error_callback error_callback, void *data)
{
size_t i;
for (i = 0; i < abbrevs->num_abbrevs; ++i)
backtrace_free (state, abbrevs->abbrevs[i].attrs,
abbrevs->abbrevs[i].num_attrs * sizeof (struct attr),
error_callback, data);
backtrace_free (state, abbrevs->abbrevs,
abbrevs->num_abbrevs * sizeof (struct abbrev),
error_callback, data);
abbrevs->num_abbrevs = 0;
abbrevs->abbrevs = NULL;
}
/* Read an attribute value. Returns 1 on success, 0 on failure. If
the value can be represented as a uint64_t, sets *VAL and sets
*IS_VALID to 1. We don't try to store the value of other attribute
forms, because we don't care about them. */
static int
read_attribute (enum dwarf_form form, uint64_t implicit_val,
struct dwarf_buf *buf, int is_dwarf64, int version,
int addrsize, const struct dwarf_sections *dwarf_sections,
struct dwarf_data *altlink, struct attr_val *val)
{
/* Avoid warnings about val.u.FIELD may be used uninitialized if
this function is inlined. The warnings aren't valid but can
occur because the different fields are set and used
conditionally. */
memset (val, 0, sizeof *val);
switch (form)
{
case DW_FORM_addr:
val->encoding = ATTR_VAL_ADDRESS;
val->u.uint = read_address (buf, addrsize);
return 1;
case DW_FORM_block2:
val->encoding = ATTR_VAL_BLOCK;
return advance (buf, read_uint16 (buf));
case DW_FORM_block4:
val->encoding = ATTR_VAL_BLOCK;
return advance (buf, read_uint32 (buf));
case DW_FORM_data2:
val->encoding = ATTR_VAL_UINT;
val->u.uint = read_uint16 (buf);
return 1;
case DW_FORM_data4:
val->encoding = ATTR_VAL_UINT;
val->u.uint = read_uint32 (buf);
return 1;
case DW_FORM_data8:
val->encoding = ATTR_VAL_UINT;
val->u.uint = read_uint64 (buf);
return 1;
case DW_FORM_data16:
val->encoding = ATTR_VAL_BLOCK;
return advance (buf, 16);
case DW_FORM_string:
val->encoding = ATTR_VAL_STRING;
val->u.string = read_string (buf);
return val->u.string == NULL ? 0 : 1;
case DW_FORM_block:
val->encoding = ATTR_VAL_BLOCK;
return advance (buf, read_uleb128 (buf));
case DW_FORM_block1:
val->encoding = ATTR_VAL_BLOCK;
return advance (buf, read_byte (buf));
case DW_FORM_data1:
val->encoding = ATTR_VAL_UINT;
val->u.uint = read_byte (buf);
return 1;
case DW_FORM_flag:
val->encoding = ATTR_VAL_UINT;
val->u.uint = read_byte (buf);
return 1;
case DW_FORM_sdata:
val->encoding = ATTR_VAL_SINT;
val->u.sint = read_sleb128 (buf);
return 1;
case DW_FORM_strp:
{
uint64_t offset;
offset = read_offset (buf, is_dwarf64);
if (offset >= dwarf_sections->size[DEBUG_STR])
{
dwarf_buf_error (buf, "DW_FORM_strp out of range", 0);
return 0;
}
val->encoding = ATTR_VAL_STRING;
val->u.string =
(const char *) dwarf_sections->data[DEBUG_STR] + offset;
return 1;
}
case DW_FORM_line_strp:
{
uint64_t offset;
offset = read_offset (buf, is_dwarf64);
if (offset >= dwarf_sections->size[DEBUG_LINE_STR])
{
dwarf_buf_error (buf, "DW_FORM_line_strp out of range", 0);
return 0;
}
val->encoding = ATTR_VAL_STRING;
val->u.string =
(const char *) dwarf_sections->data[DEBUG_LINE_STR] + offset;
return 1;
}
case DW_FORM_udata:
val->encoding = ATTR_VAL_UINT;
val->u.uint = read_uleb128 (buf);
return 1;
case DW_FORM_ref_addr:
val->encoding = ATTR_VAL_REF_INFO;
if (version == 2)
val->u.uint = read_address (buf, addrsize);
else
val->u.uint = read_offset (buf, is_dwarf64);
return 1;
case DW_FORM_ref1:
val->encoding = ATTR_VAL_REF_UNIT;
val->u.uint = read_byte (buf);
return 1;
case DW_FORM_ref2:
val->encoding = ATTR_VAL_REF_UNIT;
val->u.uint = read_uint16 (buf);
return 1;
case DW_FORM_ref4:
val->encoding = ATTR_VAL_REF_UNIT;
val->u.uint = read_uint32 (buf);
return 1;
case DW_FORM_ref8:
val->encoding = ATTR_VAL_REF_UNIT;
val->u.uint = read_uint64 (buf);
return 1;
case DW_FORM_ref_udata:
val->encoding = ATTR_VAL_REF_UNIT;
val->u.uint = read_uleb128 (buf);
return 1;
case DW_FORM_indirect:
{
uint64_t form;
form = read_uleb128 (buf);
if (form == DW_FORM_implicit_const)
{
dwarf_buf_error (buf,
"DW_FORM_indirect to DW_FORM_implicit_const",
0);
return 0;
}
return read_attribute ((enum dwarf_form) form, 0, buf, is_dwarf64,
version, addrsize, dwarf_sections, altlink,
val);
}
case DW_FORM_sec_offset:
val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_offset (buf, is_dwarf64);
return 1;
case DW_FORM_exprloc:
val->encoding = ATTR_VAL_EXPR;
return advance (buf, read_uleb128 (buf));
case DW_FORM_flag_present:
val->encoding = ATTR_VAL_UINT;
val->u.uint = 1;
return 1;
case DW_FORM_ref_sig8:
val->encoding = ATTR_VAL_REF_TYPE;
val->u.uint = read_uint64 (buf);
return 1;
case DW_FORM_strx: case DW_FORM_strx1: case DW_FORM_strx2:
case DW_FORM_strx3: case DW_FORM_strx4:
{
uint64_t offset;
switch (form)
{
case DW_FORM_strx:
offset = read_uleb128 (buf);
break;
case DW_FORM_strx1:
offset = read_byte (buf);
break;
case DW_FORM_strx2:
offset = read_uint16 (buf);
break;
case DW_FORM_strx3:
offset = read_uint24 (buf);
break;
case DW_FORM_strx4:
offset = read_uint32 (buf);
break;
default:
/* This case can't happen. */
return 0;
}
val->encoding = ATTR_VAL_STRING_INDEX;
val->u.uint = offset;
return 1;
}
case DW_FORM_addrx: case DW_FORM_addrx1: case DW_FORM_addrx2:
case DW_FORM_addrx3: case DW_FORM_addrx4:
{
uint64_t offset;
switch (form)
{
case DW_FORM_addrx:
offset = read_uleb128 (buf);
break;
case DW_FORM_addrx1:
offset = read_byte (buf);
break;
case DW_FORM_addrx2:
offset = read_uint16 (buf);
break;
case DW_FORM_addrx3:
offset = read_uint24 (buf);
break;
case DW_FORM_addrx4:
offset = read_uint32 (buf);
break;
default:
/* This case can't happen. */
return 0;
}
val->encoding = ATTR_VAL_ADDRESS_INDEX;
val->u.uint = offset;
return 1;
}
case DW_FORM_ref_sup4:
val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_uint32 (buf);
return 1;
case DW_FORM_ref_sup8:
val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_uint64 (buf);
return 1;
case DW_FORM_implicit_const:
val->encoding = ATTR_VAL_UINT;
val->u.uint = implicit_val;
return 1;
case DW_FORM_loclistx:
/* We don't distinguish this from DW_FORM_sec_offset. It
* shouldn't matter since we don't care about loclists. */
val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_uleb128 (buf);
return 1;
case DW_FORM_rnglistx:
val->encoding = ATTR_VAL_RNGLISTS_INDEX;
val->u.uint = read_uleb128 (buf);
return 1;
case DW_FORM_GNU_addr_index:
val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_uleb128 (buf);
return 1;
case DW_FORM_GNU_str_index:
val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_uleb128 (buf);
return 1;
case DW_FORM_GNU_ref_alt:
val->u.uint = read_offset (buf, is_dwarf64);
if (altlink == NULL)
{
val->encoding = ATTR_VAL_NONE;
return 1;
}
val->encoding = ATTR_VAL_REF_ALT_INFO;
return 1;
case DW_FORM_strp_sup: case DW_FORM_GNU_strp_alt:
{
uint64_t offset;
offset = read_offset (buf, is_dwarf64);
if (altlink == NULL)
{
val->encoding = ATTR_VAL_NONE;
return 1;
}
if (offset >= altlink->dwarf_sections.size[DEBUG_STR])
{
dwarf_buf_error (buf, "DW_FORM_strp_sup out of range", 0);
return 0;
}
val->encoding = ATTR_VAL_STRING;
val->u.string =
(const char *) altlink->dwarf_sections.data[DEBUG_STR] + offset;
return 1;
}
default:
dwarf_buf_error (buf, "unrecognized DWARF form", -1);
return 0;
}
}
/* If we can determine the value of a string attribute, set *STRING to
point to the string. Return 1 on success, 0 on error. If we don't
know the value, we consider that a success, and we don't change
*STRING. An error is only reported for some sort of out of range
offset. */
static int
resolve_string (const struct dwarf_sections *dwarf_sections, int is_dwarf64,
int is_bigendian, uint64_t str_offsets_base,
const struct attr_val *val,
backtrace_error_callback error_callback, void *data,
const char **string)
{
switch (val->encoding)
{
case ATTR_VAL_STRING:
*string = val->u.string;
return 1;
case ATTR_VAL_STRING_INDEX:
{
uint64_t offset;
struct dwarf_buf offset_buf;
offset = val->u.uint * (is_dwarf64 ? 8 : 4) + str_offsets_base;
if (offset + (is_dwarf64 ? 8 : 4)
> dwarf_sections->size[DEBUG_STR_OFFSETS])
{
error_callback (data, "DW_FORM_strx value out of range", 0);
return 0;
}
offset_buf.name = ".debug_str_offsets";
offset_buf.start = dwarf_sections->data[DEBUG_STR_OFFSETS];
offset_buf.buf = dwarf_sections->data[DEBUG_STR_OFFSETS] + offset;
offset_buf.left = dwarf_sections->size[DEBUG_STR_OFFSETS] - offset;
offset_buf.is_bigendian = is_bigendian;
offset_buf.error_callback = error_callback;
offset_buf.data = data;
offset_buf.reported_underflow = 0;
offset = read_offset (&offset_buf, is_dwarf64);
if (offset >= dwarf_sections->size[DEBUG_STR])
{
dwarf_buf_error (&offset_buf,
"DW_FORM_strx offset out of range",
0);
return 0;
}
*string = (const char *) dwarf_sections->data[DEBUG_STR] + offset;
return 1;
}
default:
return 1;
}
}
/* Set *ADDRESS to the real address for a ATTR_VAL_ADDRESS_INDEX.
Return 1 on success, 0 on error. */
static int
resolve_addr_index (const struct dwarf_sections *dwarf_sections,
uint64_t addr_base, int addrsize, int is_bigendian,
uint64_t addr_index,
backtrace_error_callback error_callback, void *data,
uint64_t *address)
{
uint64_t offset;
struct dwarf_buf addr_buf;
offset = addr_index * addrsize + addr_base;
if (offset + addrsize > dwarf_sections->size[DEBUG_ADDR])
{
error_callback (data, "DW_FORM_addrx value out of range", 0);
return 0;
}
addr_buf.name = ".debug_addr";
addr_buf.start = dwarf_sections->data[DEBUG_ADDR];
addr_buf.buf = dwarf_sections->data[DEBUG_ADDR] + offset;
addr_buf.left = dwarf_sections->size[DEBUG_ADDR] - offset;
addr_buf.is_bigendian = is_bigendian;
addr_buf.error_callback = error_callback;
addr_buf.data = data;
addr_buf.reported_underflow = 0;
*address = read_address (&addr_buf, addrsize);
return 1;
}
/* Compare a unit offset against a unit for bsearch. */
static int
units_search (const void *vkey, const void *ventry)
{
const size_t *key = (const size_t *) vkey;
const struct unit *entry = *((const struct unit *const *) ventry);
size_t offset;
offset = *key;
if (offset < entry->low_offset)
return -1;
else if (offset >= entry->high_offset)
return 1;
else
return 0;
}
/* Find a unit in PU containing OFFSET. */
static struct unit *
find_unit (struct unit **pu, size_t units_count, size_t offset)
{
struct unit **u;
u = bsearch (&offset, pu, units_count, sizeof (struct unit *), units_search);
return u == NULL ? NULL : *u;
}
/* Compare function_addrs for qsort. When ranges are nested, make the
smallest one sort last. */
static int
function_addrs_compare (const void *v1, const void *v2)
{
const struct function_addrs *a1 = (const struct function_addrs *) v1;
const struct function_addrs *a2 = (const struct function_addrs *) v2;
if (a1->low < a2->low)
return -1;
if (a1->low > a2->low)
return 1;
if (a1->high < a2->high)
return 1;
if (a1->high > a2->high)
return -1;
return strcmp (a1->function->name, a2->function->name);
}
/* Compare a PC against a function_addrs for bsearch. We always
allocate an entra entry at the end of the vector, so that this
routine can safely look at the next entry. Note that if there are
multiple ranges containing PC, which one will be returned is
unpredictable. We compensate for that in dwarf_fileline. */
static int
function_addrs_search (const void *vkey, const void *ventry)
{
const uintptr_t *key = (const uintptr_t *) vkey;
const struct function_addrs *entry = (const struct function_addrs *) ventry;
uintptr_t pc;
pc = *key;
if (pc < entry->low)
return -1;
else if (pc > (entry + 1)->low)
return 1;
else
return 0;
}
/* Add a new compilation unit address range to a vector. This is
called via add_ranges. Returns 1 on success, 0 on failure. */
static int
add_unit_addr (struct backtrace_state *state, void *rdata,
uint64_t lowpc, uint64_t highpc,
backtrace_error_callback error_callback, void *data,
void *pvec)
{
struct unit *u = (struct unit *) rdata;
struct unit_addrs_vector *vec = (struct unit_addrs_vector *) pvec;
struct unit_addrs *p;
/* Try to merge with the last entry. */
if (vec->count > 0)
{
p = (struct unit_addrs *) vec->vec.base + (vec->count - 1);
if ((lowpc == p->high || lowpc == p->high + 1)
&& u == p->u)
{
if (highpc > p->high)
p->high = highpc;
return 1;
}
}
p = ((struct unit_addrs *)
backtrace_vector_grow (state, sizeof (struct unit_addrs),
error_callback, data, &vec->vec));
if (p == NULL)
return 0;
p->low = lowpc;
p->high = highpc;
p->u = u;
++vec->count;
return 1;
}
/* Compare unit_addrs for qsort. When ranges are nested, make the
smallest one sort last. */
static int
unit_addrs_compare (const void *v1, const void *v2)
{
const struct unit_addrs *a1 = (const struct unit_addrs *) v1;
const struct unit_addrs *a2 = (const struct unit_addrs *) v2;
if (a1->low < a2->low)
return -1;
if (a1->low > a2->low)
return 1;
if (a1->high < a2->high)
return 1;
if (a1->high > a2->high)
return -1;
if (a1->u->lineoff < a2->u->lineoff)
return -1;
if (a1->u->lineoff > a2->u->lineoff)
return 1;
return 0;
}
/* Compare a PC against a unit_addrs for bsearch. We always allocate
an entry entry at the end of the vector, so that this routine can
safely look at the next entry. Note that if there are multiple
ranges containing PC, which one will be returned is unpredictable.
We compensate for that in dwarf_fileline. */
static int
unit_addrs_search (const void *vkey, const void *ventry)
{
const uintptr_t *key = (const uintptr_t *) vkey;
const struct unit_addrs *entry = (const struct unit_addrs *) ventry;
uintptr_t pc;
pc = *key;
if (pc < entry->low)
return -1;
else if (pc > (entry + 1)->low)
return 1;
else
return 0;
}
/* Sort the line vector by PC. We want a stable sort here to maintain
the order of lines for the same PC values. Since the sequence is
being sorted in place, their addresses cannot be relied on to
maintain stability. That is the purpose of the index member. */
static int
line_compare (const void *v1, const void *v2)
{
const struct line *ln1 = (const struct line *) v1;
const struct line *ln2 = (const struct line *) v2;
if (ln1->pc < ln2->pc)
return -1;
else if (ln1->pc > ln2->pc)
return 1;
else if (ln1->idx < ln2->idx)
return -1;
else if (ln1->idx > ln2->idx)
return 1;
else
return 0;
}
/* Find a PC in a line vector. We always allocate an extra entry at
the end of the lines vector, so that this routine can safely look
at the next entry. Note that when there are multiple mappings for
the same PC value, this will return the last one. */
static int
line_search (const void *vkey, const void *ventry)
{
const uintptr_t *key = (const uintptr_t *) vkey;
const struct line *entry = (const struct line *) ventry;
uintptr_t pc;
pc = *key;
if (pc < entry->pc)
return -1;
else if (pc >= (entry + 1)->pc)
return 1;
else
return 0;
}
/* Sort the abbrevs by the abbrev code. This function is passed to
both qsort and bsearch. */
static int
abbrev_compare (const void *v1, const void *v2)
{
const struct abbrev *a1 = (const struct abbrev *) v1;
const struct abbrev *a2 = (const struct abbrev *) v2;
if (a1->code < a2->code)
return -1;
else if (a1->code > a2->code)
return 1;
else
{
/* This really shouldn't happen. It means there are two
different abbrevs with the same code, and that means we don't
know which one lookup_abbrev should return. */
return 0;
}
}
/* Read the abbreviation table for a compilation unit. Returns 1 on
success, 0 on failure. */
static int
read_abbrevs (struct backtrace_state *state, uint64_t abbrev_offset,
const unsigned char *dwarf_abbrev, size_t dwarf_abbrev_size,
int is_bigendian, backtrace_error_callback error_callback,
void *data, struct abbrevs *abbrevs)
{
struct dwarf_buf abbrev_buf;
struct dwarf_buf count_buf;
size_t num_abbrevs;
abbrevs->num_abbrevs = 0;
abbrevs->abbrevs = NULL;
if (abbrev_offset >= dwarf_abbrev_size)
{
error_callback (data, "abbrev offset out of range", 0);
return 0;
}
abbrev_buf.name = ".debug_abbrev";
abbrev_buf.start = dwarf_abbrev;
abbrev_buf.buf = dwarf_abbrev + abbrev_offset;
abbrev_buf.left = dwarf_abbrev_size - abbrev_offset;
abbrev_buf.is_bigendian = is_bigendian;
abbrev_buf.error_callback = error_callback;
abbrev_buf.data = data;
abbrev_buf.reported_underflow = 0;
/* Count the number of abbrevs in this list. */
count_buf = abbrev_buf;
num_abbrevs = 0;
while (read_uleb128 (&count_buf) != 0)
{
if (count_buf.reported_underflow)
return 0;
++num_abbrevs;
// Skip tag.
read_uleb128 (&count_buf);
// Skip has_children.
read_byte (&count_buf);
// Skip attributes.
while (read_uleb128 (&count_buf) != 0)
{
uint64_t form;
form = read_uleb128 (&count_buf);
if ((enum dwarf_form) form == DW_FORM_implicit_const)
read_sleb128 (&count_buf);
}
// Skip form of last attribute.
read_uleb128 (&count_buf);
}
if (count_buf.reported_underflow)
return 0;
if (num_abbrevs == 0)
return 1;
abbrevs->abbrevs = ((struct abbrev *)
backtrace_alloc (state,
num_abbrevs * sizeof (struct abbrev),
error_callback, data));
if (abbrevs->abbrevs == NULL)
return 0;
abbrevs->num_abbrevs = num_abbrevs;
memset (abbrevs->abbrevs, 0, num_abbrevs * sizeof (struct abbrev));
num_abbrevs = 0;
while (1)
{
uint64_t code;
struct abbrev a;
size_t num_attrs;
struct attr *attrs;
if (abbrev_buf.reported_underflow)
goto fail;
code = read_uleb128 (&abbrev_buf);
if (code == 0)
break;
a.code = code;
a.tag = (enum dwarf_tag) read_uleb128 (&abbrev_buf);
a.has_children = read_byte (&abbrev_buf);
count_buf = abbrev_buf;
num_attrs = 0;
while (read_uleb128 (&count_buf) != 0)
{
uint64_t form;
++num_attrs;
form = read_uleb128 (&count_buf);
if ((enum dwarf_form) form == DW_FORM_implicit_const)
read_sleb128 (&count_buf);
}
if (num_attrs == 0)
{
attrs = NULL;
read_uleb128 (&abbrev_buf);
read_uleb128 (&abbrev_buf);
}
else
{
attrs = ((struct attr *)
backtrace_alloc (state, num_attrs * sizeof *attrs,
error_callback, data));
if (attrs == NULL)
goto fail;
num_attrs = 0;
while (1)
{
uint64_t name;
uint64_t form;
name = read_uleb128 (&abbrev_buf);
form = read_uleb128 (&abbrev_buf);
if (name == 0)
break;
attrs[num_attrs].name = (enum dwarf_attribute) name;
attrs[num_attrs].form = (enum dwarf_form) form;
if ((enum dwarf_form) form == DW_FORM_implicit_const)
attrs[num_attrs].val = read_sleb128 (&abbrev_buf);
else
attrs[num_attrs].val = 0;
++num_attrs;
}
}
a.num_attrs = num_attrs;
a.attrs = attrs;
abbrevs->abbrevs[num_abbrevs] = a;
++num_abbrevs;
}
backtrace_qsort (abbrevs->abbrevs, abbrevs->num_abbrevs,
sizeof (struct abbrev), abbrev_compare);
return 1;
fail:
free_abbrevs (state, abbrevs, error_callback, data);
return 0;
}
/* Return the abbrev information for an abbrev code. */
static const struct abbrev *
lookup_abbrev (struct abbrevs *abbrevs, uint64_t code,
backtrace_error_callback error_callback, void *data)
{
struct abbrev key;
void *p;
/* With GCC, where abbrevs are simply numbered in order, we should
be able to just look up the entry. */
if (code - 1 < abbrevs->num_abbrevs
&& abbrevs->abbrevs[code - 1].code == code)
return &abbrevs->abbrevs[code - 1];
/* Otherwise we have to search. */
memset (&key, 0, sizeof key);
key.code = code;
p = bsearch (&key, abbrevs->abbrevs, abbrevs->num_abbrevs,
sizeof (struct abbrev), abbrev_compare);
if (p == NULL)
{
error_callback (data, "invalid abbreviation code", 0);
return NULL;
}
return (const struct abbrev *) p;
}
/* This struct is used to gather address range information while
reading attributes. We use this while building a mapping from
address ranges to compilation units and then again while mapping
from address ranges to function entries. Normally either
lowpc/highpc is set or ranges is set. */
struct pcrange {
uint64_t lowpc; /* The low PC value. */
int have_lowpc; /* Whether a low PC value was found. */
int lowpc_is_addr_index; /* Whether lowpc is in .debug_addr. */
uint64_t highpc; /* The high PC value. */
int have_highpc; /* Whether a high PC value was found. */
int highpc_is_relative; /* Whether highpc is relative to lowpc. */
int highpc_is_addr_index; /* Whether highpc is in .debug_addr. */
uint64_t ranges; /* Offset in ranges section. */
int have_ranges; /* Whether ranges is valid. */
int ranges_is_index; /* Whether ranges is DW_FORM_rnglistx. */
};
/* Update PCRANGE from an attribute value. */
static void
update_pcrange (const struct attr* attr, const struct attr_val* val,
struct pcrange *pcrange)
{
switch (attr->name)
{
case DW_AT_low_pc:
if (val->encoding == ATTR_VAL_ADDRESS)
{
pcrange->lowpc = val->u.uint;
pcrange->have_lowpc = 1;
}
else if (val->encoding == ATTR_VAL_ADDRESS_INDEX)
{
pcrange->lowpc = val->u.uint;
pcrange->have_lowpc = 1;
pcrange->lowpc_is_addr_index = 1;
}
break;
case DW_AT_high_pc:
if (val->encoding == ATTR_VAL_ADDRESS)
{
pcrange->highpc = val->u.uint;
pcrange->have_highpc = 1;
}
else if (val->encoding == ATTR_VAL_UINT)
{
pcrange->highpc = val->u.uint;
pcrange->have_highpc = 1;
pcrange->highpc_is_relative = 1;
}
else if (val->encoding == ATTR_VAL_ADDRESS_INDEX)
{
pcrange->highpc = val->u.uint;
pcrange->have_highpc = 1;
pcrange->highpc_is_addr_index = 1;
}
break;
case DW_AT_ranges:
if (val->encoding == ATTR_VAL_UINT
|| val->encoding == ATTR_VAL_REF_SECTION)
{
pcrange->ranges = val->u.uint;
pcrange->have_ranges = 1;
}
else if (val->encoding == ATTR_VAL_RNGLISTS_INDEX)
{
pcrange->ranges = val->u.uint;
pcrange->have_ranges = 1;
pcrange->ranges_is_index = 1;
}
break;
default:
break;
}
}
/* Call ADD_RANGE for a low/high PC pair. Returns 1 on success, 0 on
error. */
static int
add_low_high_range (struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct unit *u, const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state,
void *rdata, uint64_t lowpc,
uint64_t highpc,
backtrace_error_callback error_callback,
void *data, void *vec),
void *rdata,
backtrace_error_callback error_callback, void *data,
void *vec)
{
uint64_t lowpc;
uint64_t highpc;
lowpc = pcrange->lowpc;
if (pcrange->lowpc_is_addr_index)
{
if (!resolve_addr_index (dwarf_sections, u->addr_base, u->addrsize,
is_bigendian, lowpc, error_callback, data,
&lowpc))
return 0;
}
highpc = pcrange->highpc;
if (pcrange->highpc_is_addr_index)
{
if (!resolve_addr_index (dwarf_sections, u->addr_base, u->addrsize,
is_bigendian, highpc, error_callback, data,
&highpc))
return 0;
}
if (pcrange->highpc_is_relative)
highpc += lowpc;
/* Add in the base address of the module when recording PC values,
so that we can look up the PC directly. */
lowpc += base_address;
highpc += base_address;
return add_range (state, rdata, lowpc, highpc, error_callback, data, vec);
}
/* Call ADD_RANGE for each range read from .debug_ranges, as used in
DWARF versions 2 through 4. */
static int
add_ranges_from_ranges (
struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct unit *u, uint64_t base,
const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state, void *rdata,
uint64_t lowpc, uint64_t highpc,
backtrace_error_callback error_callback, void *data,
void *vec),
void *rdata,
backtrace_error_callback error_callback, void *data,
void *vec)
{
struct dwarf_buf ranges_buf;
if (pcrange->ranges >= dwarf_sections->size[DEBUG_RANGES])
{
error_callback (data, "ranges offset out of range", 0);
return 0;
}
ranges_buf.name = ".debug_ranges";
ranges_buf.start = dwarf_sections->data[DEBUG_RANGES];
ranges_buf.buf = dwarf_sections->data[DEBUG_RANGES] + pcrange->ranges;
ranges_buf.left = dwarf_sections->size[DEBUG_RANGES] - pcrange->ranges;
ranges_buf.is_bigendian = is_bigendian;
ranges_buf.error_callback = error_callback;
ranges_buf.data = data;
ranges_buf.reported_underflow = 0;
while (1)
{
uint64_t low;
uint64_t high;
if (ranges_buf.reported_underflow)
return 0;
low = read_address (&ranges_buf, u->addrsize);
high = read_address (&ranges_buf, u->addrsize);
if (low == 0 && high == 0)
break;
if (is_highest_address (low, u->addrsize))
base = high;
else
{
if (!add_range (state, rdata,
low + base + base_address,
high + base + base_address,
error_callback, data, vec))
return 0;
}
}
if (ranges_buf.reported_underflow)
return 0;
return 1;
}
/* Call ADD_RANGE for each range read from .debug_rnglists, as used in
DWARF version 5. */
static int
add_ranges_from_rnglists (
struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct unit *u, uint64_t base,
const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state, void *rdata,
uint64_t lowpc, uint64_t highpc,
backtrace_error_callback error_callback, void *data,
void *vec),
void *rdata,
backtrace_error_callback error_callback, void *data,
void *vec)
{
uint64_t offset;
struct dwarf_buf rnglists_buf;
if (!pcrange->ranges_is_index)
offset = pcrange->ranges;
else
offset = u->rnglists_base + pcrange->ranges * (u->is_dwarf64 ? 8 : 4);
if (offset >= dwarf_sections->size[DEBUG_RNGLISTS])
{
error_callback (data, "rnglists offset out of range", 0);
return 0;
}
rnglists_buf.name = ".debug_rnglists";
rnglists_buf.start = dwarf_sections->data[DEBUG_RNGLISTS];
rnglists_buf.buf = dwarf_sections->data[DEBUG_RNGLISTS] + offset;
rnglists_buf.left = dwarf_sections->size[DEBUG_RNGLISTS] - offset;
rnglists_buf.is_bigendian = is_bigendian;
rnglists_buf.error_callback = error_callback;
rnglists_buf.data = data;
rnglists_buf.reported_underflow = 0;
if (pcrange->ranges_is_index)
{
offset = read_offset (&rnglists_buf, u->is_dwarf64);
offset += u->rnglists_base;
if (offset >= dwarf_sections->size[DEBUG_RNGLISTS])
{
error_callback (data, "rnglists index offset out of range", 0);
return 0;
}
rnglists_buf.buf = dwarf_sections->data[DEBUG_RNGLISTS] + offset;
rnglists_buf.left = dwarf_sections->size[DEBUG_RNGLISTS] - offset;
}
while (1)
{
unsigned char rle;
rle = read_byte (&rnglists_buf);
if (rle == DW_RLE_end_of_list)
break;
switch (rle)
{
case DW_RLE_base_addressx:
{
uint64_t index;
index = read_uleb128 (&rnglists_buf);
if (!resolve_addr_index (dwarf_sections, u->addr_base,
u->addrsize, is_bigendian, index,
error_callback, data, &base))
return 0;
}
break;
case DW_RLE_startx_endx:
{
uint64_t index;
uint64_t low;
uint64_t high;
index = read_uleb128 (&rnglists_buf);
if (!resolve_addr_index (dwarf_sections, u->addr_base,
u->addrsize, is_bigendian, index,
error_callback, data, &low))
return 0;
index = read_uleb128 (&rnglists_buf);
if (!resolve_addr_index (dwarf_sections, u->addr_base,
u->addrsize, is_bigendian, index,
error_callback, data, &high))
return 0;
if (!add_range (state, rdata, low + base_address,
high + base_address, error_callback, data,
vec))
return 0;
}
break;
case DW_RLE_startx_length:
{
uint64_t index;
uint64_t low;
uint64_t length;
index = read_uleb128 (&rnglists_buf);
if (!resolve_addr_index (dwarf_sections, u->addr_base,
u->addrsize, is_bigendian, index,
error_callback, data, &low))
return 0;
length = read_uleb128 (&rnglists_buf);
low += base_address;
if (!add_range (state, rdata, low, low + length,
error_callback, data, vec))
return 0;
}
break;
case DW_RLE_offset_pair:
{
uint64_t low;
uint64_t high;
low = read_uleb128 (&rnglists_buf);
high = read_uleb128 (&rnglists_buf);
if (!add_range (state, rdata, low + base + base_address,
high + base + base_address,
error_callback, data, vec))
return 0;
}
break;
case DW_RLE_base_address:
base = read_address (&rnglists_buf, u->addrsize);
break;
case DW_RLE_start_end:
{
uint64_t low;
uint64_t high;
low = read_address (&rnglists_buf, u->addrsize);
high = read_address (&rnglists_buf, u->addrsize);
if (!add_range (state, rdata, low + base_address,
high + base_address, error_callback, data,
vec))
return 0;
}
break;
case DW_RLE_start_length:
{
uint64_t low;
uint64_t length;
low = read_address (&rnglists_buf, u->addrsize);
length = read_uleb128 (&rnglists_buf);
low += base_address;
if (!add_range (state, rdata, low, low + length,
error_callback, data, vec))
return 0;
}
break;
default:
dwarf_buf_error (&rnglists_buf, "unrecognized DW_RLE value", -1);
return 0;
}
}
if (rnglists_buf.reported_underflow)
return 0;
return 1;
}
/* Call ADD_RANGE for each lowpc/highpc pair in PCRANGE. RDATA is
passed to ADD_RANGE, and is either a struct unit * or a struct
function *. VEC is the vector we are adding ranges to, and is
either a struct unit_addrs_vector * or a struct function_vector *.
Returns 1 on success, 0 on error. */
static int
add_ranges (struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct unit *u, uint64_t base, const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state, void *rdata,
uint64_t lowpc, uint64_t highpc,
backtrace_error_callback error_callback,
void *data, void *vec),
void *rdata,
backtrace_error_callback error_callback, void *data,
void *vec)
{
if (pcrange->have_lowpc && pcrange->have_highpc)
return add_low_high_range (state, dwarf_sections, base_address,
is_bigendian, u, pcrange, add_range, rdata,
error_callback, data, vec);
if (!pcrange->have_ranges)
{
/* Did not find any address ranges to add. */
return 1;
}
if (u->version < 5)
return add_ranges_from_ranges (state, dwarf_sections, base_address,
is_bigendian, u, base, pcrange, add_range,
rdata, error_callback, data, vec);
else
return add_ranges_from_rnglists (state, dwarf_sections, base_address,
is_bigendian, u, base, pcrange, add_range,
rdata, error_callback, data, vec);
}
/* Find the address range covered by a compilation unit, reading from
UNIT_BUF and adding values to U. Returns 1 if all data could be
read, 0 if there is some error. */
static int
find_address_ranges (struct backtrace_state *state, uintptr_t base_address,
struct dwarf_buf *unit_buf,
const struct dwarf_sections *dwarf_sections,
int is_bigendian, struct dwarf_data *altlink,
backtrace_error_callback error_callback, void *data,
struct unit *u, struct unit_addrs_vector *addrs,
enum dwarf_tag *unit_tag)
{
while (unit_buf->left > 0)
{
uint64_t code;
const struct abbrev *abbrev;
struct pcrange pcrange;
struct attr_val name_val;
int have_name_val;
struct attr_val comp_dir_val;
int have_comp_dir_val;
size_t i;
code = read_uleb128 (unit_buf);
if (code == 0)
return 1;
abbrev = lookup_abbrev (&u->abbrevs, code, error_callback, data);
if (abbrev == NULL)
return 0;
if (unit_tag != NULL)
*unit_tag = abbrev->tag;
memset (&pcrange, 0, sizeof pcrange);
memset (&name_val, 0, sizeof name_val);
have_name_val = 0;
memset (&comp_dir_val, 0, sizeof comp_dir_val);
have_comp_dir_val = 0;
for (i = 0; i < abbrev->num_attrs; ++i)
{
struct attr_val val;
if (!read_attribute (abbrev->attrs[i].form, abbrev->attrs[i].val,
unit_buf, u->is_dwarf64, u->version,
u->addrsize, dwarf_sections, altlink, &val))
return 0;
switch (abbrev->attrs[i].name)
{
case DW_AT_low_pc: case DW_AT_high_pc: case DW_AT_ranges:
update_pcrange (&abbrev->attrs[i], &val, &pcrange);
break;
case DW_AT_stmt_list:
if (abbrev->tag == DW_TAG_compile_unit
&& (val.encoding == ATTR_VAL_UINT
|| val.encoding == ATTR_VAL_REF_SECTION))
u->lineoff = val.u.uint;
break;
case DW_AT_name:
if (abbrev->tag == DW_TAG_compile_unit)
{
name_val = val;
have_name_val = 1;
}
break;
case DW_AT_comp_dir:
if (abbrev->tag == DW_TAG_compile_unit)
{
comp_dir_val = val;
have_comp_dir_val = 1;
}
break;
case DW_AT_str_offsets_base:
if (abbrev->tag == DW_TAG_compile_unit
&& val.encoding == ATTR_VAL_REF_SECTION)
u->str_offsets_base = val.u.uint;
break;
case DW_AT_addr_base:
if (abbrev->tag == DW_TAG_compile_unit
&& val.encoding == ATTR_VAL_REF_SECTION)
u->addr_base = val.u.uint;
break;
case DW_AT_rnglists_base:
if (abbrev->tag == DW_TAG_compile_unit
&& val.encoding == ATTR_VAL_REF_SECTION)
u->rnglists_base = val.u.uint;
break;
default:
break;
}
}
// Resolve strings after we're sure that we have seen
// DW_AT_str_offsets_base.
if (have_name_val)
{
if (!resolve_string (dwarf_sections, u->is_dwarf64, is_bigendian,
u->str_offsets_base, &name_val,
error_callback, data, &u->filename))
return 0;
}
if (have_comp_dir_val)
{
if (!resolve_string (dwarf_sections, u->is_dwarf64, is_bigendian,
u->str_offsets_base, &comp_dir_val,
error_callback, data, &u->comp_dir))
return 0;
}
if (abbrev->tag == DW_TAG_compile_unit
|| abbrev->tag == DW_TAG_subprogram)
{
if (!add_ranges (state, dwarf_sections, base_address,
is_bigendian, u, pcrange.lowpc, &pcrange,
add_unit_addr, (void *) u, error_callback, data,
(void *) addrs))
return 0;
/* If we found the PC range in the DW_TAG_compile_unit, we
can stop now. */
if (abbrev->tag == DW_TAG_compile_unit
&& (pcrange.have_ranges
|| (pcrange.have_lowpc && pcrange.have_highpc)))
return 1;
}
if (abbrev->has_children)
{
if (!find_address_ranges (state, base_address, unit_buf,
dwarf_sections, is_bigendian, altlink,
error_callback, data, u, addrs, NULL))
return 0;
}
}
return 1;
}
/* Build a mapping from address ranges to the compilation units where
the line number information for that range can be found. Returns 1
on success, 0 on failure. */
static int
build_address_map (struct backtrace_state *state, uintptr_t base_address,
const struct dwarf_sections *dwarf_sections,
int is_bigendian, struct dwarf_data *altlink,
backtrace_error_callback error_callback, void *data,
struct unit_addrs_vector *addrs,
struct unit_vector *unit_vec)
{
struct dwarf_buf info;
struct backtrace_vector units;
size_t units_count;
size_t i;
struct unit **pu;
size_t unit_offset = 0;
struct unit_addrs *pa;
memset (&addrs->vec, 0, sizeof addrs->vec);
memset (&unit_vec->vec, 0, sizeof unit_vec->vec);
addrs->count = 0;
unit_vec->count = 0;
/* Read through the .debug_info section. FIXME: Should we use the
.debug_aranges section? gdb and addr2line don't use it, but I'm
not sure why. */
info.name = ".debug_info";
info.start = dwarf_sections->data[DEBUG_INFO];
info.buf = info.start;
info.left = dwarf_sections->size[DEBUG_INFO];
info.is_bigendian = is_bigendian;
info.error_callback = error_callback;
info.data = data;
info.reported_underflow = 0;
memset (&units, 0, sizeof units);
units_count = 0;
while (info.left > 0)
{
const unsigned char *unit_data_start;
uint64_t len;
int is_dwarf64;
struct dwarf_buf unit_buf;
int version;
int unit_type;
uint64_t abbrev_offset;
int addrsize;
struct unit *u;
enum dwarf_tag unit_tag;
if (info.reported_underflow)
goto fail;
unit_data_start = info.buf;
len = read_initial_length (&info, &is_dwarf64);
unit_buf = info;
unit_buf.left = len;
if (!advance (&info, len))
goto fail;
version = read_uint16 (&unit_buf);
if (version < 2 || version > 5)
{
dwarf_buf_error (&unit_buf, "unrecognized DWARF version", -1);
goto fail;
}
if (version < 5)
unit_type = 0;
else
{
unit_type = read_byte (&unit_buf);
if (unit_type == DW_UT_type || unit_type == DW_UT_split_type)
{
/* This unit doesn't have anything we need. */
continue;
}
}
pu = ((struct unit **)
backtrace_vector_grow (state, sizeof (struct unit *),
error_callback, data, &units));
if (pu == NULL)
goto fail;
u = ((struct unit *)
backtrace_alloc (state, sizeof *u, error_callback, data));
if (u == NULL)
goto fail;
*pu = u;
++units_count;
if (version < 5)
addrsize = 0; /* Set below. */
else
addrsize = read_byte (&unit_buf);
memset (&u->abbrevs, 0, sizeof u->abbrevs);
abbrev_offset = read_offset (&unit_buf, is_dwarf64);
if (!read_abbrevs (state, abbrev_offset,
dwarf_sections->data[DEBUG_ABBREV],
dwarf_sections->size[DEBUG_ABBREV],
is_bigendian, error_callback, data, &u->abbrevs))
goto fail;
if (version < 5)
addrsize = read_byte (&unit_buf);
switch (unit_type)
{
case 0:
break;
case DW_UT_compile: case DW_UT_partial:
break;
case DW_UT_skeleton: case DW_UT_split_compile:
read_uint64 (&unit_buf); /* dwo_id */
break;
default:
break;
}
u->low_offset = unit_offset;
unit_offset += len + (is_dwarf64 ? 12 : 4);
u->high_offset = unit_offset;
u->unit_data = unit_buf.buf;
u->unit_data_len = unit_buf.left;
u->unit_data_offset = unit_buf.buf - unit_data_start;
u->version = version;
u->is_dwarf64 = is_dwarf64;
u->addrsize = addrsize;
u->filename = NULL;
u->comp_dir = NULL;
u->abs_filename = NULL;
u->lineoff = 0;
/* The actual line number mappings will be read as needed. */
u->lines = NULL;
u->lines_count = 0;
u->function_addrs = NULL;
u->function_addrs_count = 0;
if (!find_address_ranges (state, base_address, &unit_buf, dwarf_sections,
is_bigendian, altlink, error_callback, data,
u, addrs, &unit_tag))
goto fail;
if (unit_buf.reported_underflow)
goto fail;
}
if (info.reported_underflow)
goto fail;
/* Add a trailing addrs entry, but don't include it in addrs->count. */
pa = ((struct unit_addrs *)
backtrace_vector_grow (state, sizeof (struct unit_addrs),
error_callback, data, &addrs->vec));
if (pa == NULL)
goto fail;
pa->low = 0;
--pa->low;
pa->high = pa->low;
pa->u = NULL;
unit_vec->vec = units;
unit_vec->count = units_count;
return 1;
fail:
if (units_count > 0)
{
pu = (struct unit **) units.base;
for (i = 0; i < units_count; i++)
{
free_abbrevs (state, &pu[i]->abbrevs, error_callback, data);
backtrace_free (state, pu[i], sizeof **pu, error_callback, data);
}
backtrace_vector_free (state, &units, error_callback, data);
}
if (addrs->count > 0)
{
backtrace_vector_free (state, &addrs->vec, error_callback, data);
addrs->count = 0;
}
return 0;
}
/* Add a new mapping to the vector of line mappings that we are
building. Returns 1 on success, 0 on failure. */
static int
add_line (struct backtrace_state *state, struct dwarf_data *ddata,
uintptr_t pc, const char *filename, int lineno,
backtrace_error_callback error_callback, void *data,
struct line_vector *vec)
{
struct line *ln;
/* If we are adding the same mapping, ignore it. This can happen
when using discriminators. */
if (vec->count > 0)
{
ln = (struct line *) vec->vec.base + (vec->count - 1);
if (pc == ln->pc && filename == ln->filename && lineno == ln->lineno)
return 1;
}
ln = ((struct line *)
backtrace_vector_grow (state, sizeof (struct line), error_callback,
data, &vec->vec));
if (ln == NULL)
return 0;
/* Add in the base address here, so that we can look up the PC
directly. */
ln->pc = pc + ddata->base_address;
ln->filename = filename;
ln->lineno = lineno;
ln->idx = vec->count;
++vec->count;
return 1;
}
/* Free the line header information. */
static void
free_line_header (struct backtrace_state *state, struct line_header *hdr,
backtrace_error_callback error_callback, void *data)
{
if (hdr->dirs_count != 0)
backtrace_free (state, hdr->dirs, hdr->dirs_count * sizeof (const char *),
error_callback, data);
backtrace_free (state, hdr->filenames,
hdr->filenames_count * sizeof (char *),
error_callback, data);
}
/* Read the directories and file names for a line header for version
2, setting fields in HDR. Return 1 on success, 0 on failure. */
static int
read_v2_paths (struct backtrace_state *state, struct unit *u,
struct dwarf_buf *hdr_buf, struct line_header *hdr)
{
const unsigned char *p;
const unsigned char *pend;
size_t i;
/* Count the number of directory entries. */
hdr->dirs_count = 0;
p = hdr_buf->buf;
pend = p + hdr_buf->left;
while (p < pend && *p != '\0')
{
p += strnlen((const char *) p, pend - p) + 1;
++hdr->dirs_count;
}
/* The index of the first entry in the list of directories is 1. Index 0 is
used for the current directory of the compilation. To simplify index
handling, we set entry 0 to the compilation unit directory. */
++hdr->dirs_count;
hdr->dirs = ((const char **)
backtrace_alloc (state,
hdr->dirs_count * sizeof (const char *),
hdr_buf->error_callback,
hdr_buf->data));
if (hdr->dirs == NULL)
return 0;
hdr->dirs[0] = u->comp_dir;
i = 1;
while (*hdr_buf->buf != '\0')
{
if (hdr_buf->reported_underflow)
return 0;
hdr->dirs[i] = read_string (hdr_buf);
if (hdr->dirs[i] == NULL)
return 0;
++i;
}
if (!advance (hdr_buf, 1))
return 0;
/* Count the number of file entries. */
hdr->filenames_count = 0;
p = hdr_buf->buf;
pend = p + hdr_buf->left;
while (p < pend && *p != '\0')
{
p += strnlen ((const char *) p, pend - p) + 1;
p += leb128_len (p);
p += leb128_len (p);
p += leb128_len (p);
++hdr->filenames_count;
}
/* The index of the first entry in the list of file names is 1. Index 0 is
used for the DW_AT_name of the compilation unit. To simplify index
handling, we set entry 0 to the compilation unit file name. */
++hdr->filenames_count;
hdr->filenames = ((const char **)
backtrace_alloc (state,
hdr->filenames_count * sizeof (char *),
hdr_buf->error_callback,
hdr_buf->data));
if (hdr->filenames == NULL)
return 0;
hdr->filenames[0] = u->filename;
i = 1;
while (*hdr_buf->buf != '\0')
{
const char *filename;
uint64_t dir_index;
if (hdr_buf->reported_underflow)
return 0;
filename = read_string (hdr_buf);
if (filename == NULL)
return 0;
dir_index = read_uleb128 (hdr_buf);
if (IS_ABSOLUTE_PATH (filename)
|| (dir_index < hdr->dirs_count && hdr->dirs[dir_index] == NULL))
hdr->filenames[i] = filename;
else
{
const char *dir;
size_t dir_len;
size_t filename_len;
char *s;
if (dir_index < hdr->dirs_count)
dir = hdr->dirs[dir_index];
else
{
dwarf_buf_error (hdr_buf,
("invalid directory index in "
"line number program header"),
0);
return 0;
}
dir_len = strlen (dir);
filename_len = strlen (filename);
s = ((char *) backtrace_alloc (state, dir_len + filename_len + 2,
hdr_buf->error_callback,
hdr_buf->data));
if (s == NULL)
return 0;
memcpy (s, dir, dir_len);
/* FIXME: If we are on a DOS-based file system, and the
directory or the file name use backslashes, then we
should use a backslash here. */
s[dir_len] = '/';
memcpy (s + dir_len + 1, filename, filename_len + 1);
hdr->filenames[i] = s;
}
/* Ignore the modification time and size. */
read_uleb128 (hdr_buf);
read_uleb128 (hdr_buf);
++i;
}
return 1;
}
/* Read a single version 5 LNCT entry for a directory or file name in a
line header. Sets *STRING to the resulting name, ignoring other
data. Return 1 on success, 0 on failure. */
static int
read_lnct (struct backtrace_state *state, struct dwarf_data *ddata,
struct unit *u, struct dwarf_buf *hdr_buf,
const struct line_header *hdr, size_t formats_count,
const struct line_header_format *formats, const char **string)
{
size_t i;
const char *dir;
const char *path;
dir = NULL;
path = NULL;
for (i = 0; i < formats_count; i++)
{
struct attr_val val;
if (!read_attribute (formats[i].form, 0, hdr_buf, u->is_dwarf64,
u->version, hdr->addrsize, &ddata->dwarf_sections,
ddata->altlink, &val))
return 0;
switch (formats[i].lnct)
{
case DW_LNCT_path:
if (!resolve_string (&ddata->dwarf_sections, u->is_dwarf64,
ddata->is_bigendian, u->str_offsets_base,
&val, hdr_buf->error_callback, hdr_buf->data,
&path))
return 0;
break;
case DW_LNCT_directory_index:
if (val.encoding == ATTR_VAL_UINT)
{
if (val.u.uint >= hdr->dirs_count)
{
dwarf_buf_error (hdr_buf,
("invalid directory index in "
"line number program header"),
0);
return 0;
}
dir = hdr->dirs[val.u.uint];
}
break;
default:
/* We don't care about timestamps or sizes or hashes. */
break;
}
}
if (path == NULL)
{
dwarf_buf_error (hdr_buf,
"missing file name in line number program header",
0);
return 0;
}
if (dir == NULL)
*string = path;
else
{
size_t dir_len;
size_t path_len;
char *s;
dir_len = strlen (dir);
path_len = strlen (path);
s = (char *) backtrace_alloc (state, dir_len + path_len + 2,
hdr_buf->error_callback, hdr_buf->data);
if (s == NULL)
return 0;
memcpy (s, dir, dir_len);
/* FIXME: If we are on a DOS-based file system, and the
directory or the path name use backslashes, then we should
use a backslash here. */
s[dir_len] = '/';
memcpy (s + dir_len + 1, path, path_len + 1);
*string = s;
}
return 1;
}
/* Read a set of DWARF 5 line header format entries, setting *PCOUNT
and *PPATHS. Return 1 on success, 0 on failure. */
static int
read_line_header_format_entries (struct backtrace_state *state,
struct dwarf_data *ddata,
struct unit *u,
struct dwarf_buf *hdr_buf,
struct line_header *hdr,
size_t *pcount,
const char ***ppaths)
{
size_t formats_count;
struct line_header_format *formats;
size_t paths_count;
const char **paths;
size_t i;
int ret;
formats_count = read_byte (hdr_buf);
if (formats_count == 0)
formats = NULL;
else
{
formats = ((struct line_header_format *)
backtrace_alloc (state,
(formats_count
* sizeof (struct line_header_format)),
hdr_buf->error_callback,
hdr_buf->data));
if (formats == NULL)
return 0;
for (i = 0; i < formats_count; i++)
{
formats[i].lnct = (int) read_uleb128(hdr_buf);
formats[i].form = (enum dwarf_form) read_uleb128 (hdr_buf);
}
}
paths_count = read_uleb128 (hdr_buf);
if (paths_count == 0)
{
*pcount = 0;
*ppaths = NULL;
ret = 1;
goto exit;
}
paths = ((const char **)
backtrace_alloc (state, paths_count * sizeof (const char *),
hdr_buf->error_callback, hdr_buf->data));
if (paths == NULL)
{
ret = 0;
goto exit;
}
for (i = 0; i < paths_count; i++)
{
if (!read_lnct (state, ddata, u, hdr_buf, hdr, formats_count,
formats, &paths[i]))
{
backtrace_free (state, paths,
paths_count * sizeof (const char *),
hdr_buf->error_callback, hdr_buf->data);
ret = 0;
goto exit;
}
}
*pcount = paths_count;
*ppaths = paths;
ret = 1;
exit:
if (formats != NULL)
backtrace_free (state, formats,
formats_count * sizeof (struct line_header_format),
hdr_buf->error_callback, hdr_buf->data);
return ret;
}
/* Read the line header. Return 1 on success, 0 on failure. */
static int
read_line_header (struct backtrace_state *state, struct dwarf_data *ddata,
struct unit *u, int is_dwarf64, struct dwarf_buf *line_buf,
struct line_header *hdr)
{
uint64_t hdrlen;
struct dwarf_buf hdr_buf;
hdr->version = read_uint16 (line_buf);
if (hdr->version < 2 || hdr->version > 5)
{
dwarf_buf_error (line_buf, "unsupported line number version", -1);
return 0;
}
if (hdr->version < 5)
hdr->addrsize = u->addrsize;
else
{
hdr->addrsize = read_byte (line_buf);
/* We could support a non-zero segment_selector_size but I doubt
we'll ever see it. */
if (read_byte (line_buf) != 0)
{
dwarf_buf_error (line_buf,
"non-zero segment_selector_size not supported",
-1);
return 0;
}
}
hdrlen = read_offset (line_buf, is_dwarf64);
hdr_buf = *line_buf;
hdr_buf.left = hdrlen;
if (!advance (line_buf, hdrlen))
return 0;
hdr->min_insn_len = read_byte (&hdr_buf);
if (hdr->version < 4)
hdr->max_ops_per_insn = 1;
else
hdr->max_ops_per_insn = read_byte (&hdr_buf);
/* We don't care about default_is_stmt. */
read_byte (&hdr_buf);
hdr->line_base = read_sbyte (&hdr_buf);
hdr->line_range = read_byte (&hdr_buf);
hdr->opcode_base = read_byte (&hdr_buf);
hdr->opcode_lengths = hdr_buf.buf;
if (!advance (&hdr_buf, hdr->opcode_base - 1))
return 0;
if (hdr->version < 5)
{
if (!read_v2_paths (state, u, &hdr_buf, hdr))
return 0;
}
else
{
if (!read_line_header_format_entries (state, ddata, u, &hdr_buf, hdr,
&hdr->dirs_count,
&hdr->dirs))
return 0;
if (!read_line_header_format_entries (state, ddata, u, &hdr_buf, hdr,
&hdr->filenames_count,
&hdr->filenames))
return 0;
}
if (hdr_buf.reported_underflow)
return 0;
return 1;
}
/* Read the line program, adding line mappings to VEC. Return 1 on
success, 0 on failure. */
static int
read_line_program (struct backtrace_state *state, struct dwarf_data *ddata,
const struct line_header *hdr, struct dwarf_buf *line_buf,
struct line_vector *vec)
{
uint64_t address;
unsigned int op_index;
const char *reset_filename;
const char *filename;
int lineno;
address = 0;
op_index = 0;
if (hdr->filenames_count > 1)
reset_filename = hdr->filenames[1];
else
reset_filename = "";
filename = reset_filename;
lineno = 1;
while (line_buf->left > 0)
{
unsigned int op;
op = read_byte (line_buf);
if (op >= hdr->opcode_base)
{
unsigned int advance;
/* Special opcode. */
op -= hdr->opcode_base;
advance = op / hdr->line_range;
address += (hdr->min_insn_len * (op_index + advance)
/ hdr->max_ops_per_insn);
op_index = (op_index + advance) % hdr->max_ops_per_insn;
lineno += hdr->line_base + (int) (op % hdr->line_range);
add_line (state, ddata, address, filename, lineno,
line_buf->error_callback, line_buf->data, vec);
}
else if (op == DW_LNS_extended_op)
{
uint64_t len;
len = read_uleb128 (line_buf);
op = read_byte (line_buf);
switch (op)
{
case DW_LNE_end_sequence:
/* FIXME: Should we mark the high PC here? It seems
that we already have that information from the
compilation unit. */
address = 0;
op_index = 0;