diff options
Diffstat (limited to 'libdw/dwarf_getmacros.c')
| -rw-r--r-- | libdw/dwarf_getmacros.c | 548 |
1 files changed, 548 insertions, 0 deletions
diff --git a/libdw/dwarf_getmacros.c b/libdw/dwarf_getmacros.c new file mode 100644 index 00000000..f9f29961 --- /dev/null +++ b/libdw/dwarf_getmacros.c @@ -0,0 +1,548 @@ +/* Get macro information. + Copyright (C) 2002-2009, 2014 Red Hat, Inc. + This file is part of elfutils. + Written by Ulrich Drepper <drepper@redhat.com>, 2002. + + This file is free software; you can redistribute it and/or modify + it under the terms of either + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at + your option) any later version + + or + + * the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at + your option) any later version + + or both in parallel, as here. + + elfutils 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. + + You should have received copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see <http://www.gnu.org/licenses/>. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <assert.h> +#include <dwarf.h> +#include <search.h> +#include <stdlib.h> +#include <string.h> + +#include <libdwP.h> + +static int +get_offset_from (Dwarf_Die *die, int name, Dwarf_Word *retp) +{ + /* Get the appropriate attribute. */ + Dwarf_Attribute attr; + if (INTUSE(dwarf_attr) (die, name, &attr) == NULL) + return -1; + + /* Offset into the corresponding section. */ + return INTUSE(dwarf_formudata) (&attr, retp); +} + +static int +macro_op_compare (const void *p1, const void *p2) +{ + const Dwarf_Macro_Op_Table *t1 = (const Dwarf_Macro_Op_Table *) p1; + const Dwarf_Macro_Op_Table *t2 = (const Dwarf_Macro_Op_Table *) p2; + + if (t1->offset < t2->offset) + return -1; + if (t1->offset > t2->offset) + return 1; + + if (t1->sec_index < t2->sec_index) + return -1; + if (t1->sec_index > t2->sec_index) + return 1; + + return 0; +} + +static void +build_table (Dwarf_Macro_Op_Table *table, + Dwarf_Macro_Op_Proto op_protos[static 255]) +{ + unsigned ct = 0; + for (unsigned i = 1; i < 256; ++i) + if (op_protos[i - 1].forms != NULL) + table->table[table->opcodes[i - 1] = ct++] = op_protos[i - 1]; + else + table->opcodes[i - 1] = 0xff; +} + +#define MACRO_PROTO(NAME, ...) \ + Dwarf_Macro_Op_Proto NAME = ({ \ + static const uint8_t proto[] = {__VA_ARGS__}; \ + (Dwarf_Macro_Op_Proto) {sizeof proto, proto}; \ + }) + +enum { macinfo_data_size = offsetof (Dwarf_Macro_Op_Table, table[5]) }; +static unsigned char macinfo_data[macinfo_data_size] + __attribute__ ((aligned (__alignof (Dwarf_Macro_Op_Table)))); + +static __attribute__ ((constructor)) void +init_macinfo_table (void) +{ + MACRO_PROTO (p_udata_str, DW_FORM_udata, DW_FORM_string); + MACRO_PROTO (p_udata_udata, DW_FORM_udata, DW_FORM_udata); + MACRO_PROTO (p_none); + + Dwarf_Macro_Op_Proto op_protos[255] = + { + [DW_MACINFO_define - 1] = p_udata_str, + [DW_MACINFO_undef - 1] = p_udata_str, + [DW_MACINFO_vendor_ext - 1] = p_udata_str, + [DW_MACINFO_start_file - 1] = p_udata_udata, + [DW_MACINFO_end_file - 1] = p_none, + /* If you are adding more elements to this array, increase + MACINFO_DATA_SIZE above. */ + }; + + Dwarf_Macro_Op_Table *macinfo_table = (void *) macinfo_data; + memset (macinfo_table, 0, sizeof macinfo_data); + build_table (macinfo_table, op_protos); + macinfo_table->sec_index = IDX_debug_macinfo; +} + +static Dwarf_Macro_Op_Table * +get_macinfo_table (Dwarf *dbg, Dwarf_Word macoff, Dwarf_Die *cudie) +{ + assert (cudie != NULL); + + Dwarf_Attribute attr_mem, *attr + = INTUSE(dwarf_attr) (cudie, DW_AT_stmt_list, &attr_mem); + Dwarf_Off line_offset = (Dwarf_Off) -1; + if (attr != NULL) + INTUSE(dwarf_formudata) (attr, &line_offset); + + Dwarf_Macro_Op_Table *table = libdw_alloc (dbg, Dwarf_Macro_Op_Table, + macinfo_data_size, 1); + memcpy (table, macinfo_data, macinfo_data_size); + + table->offset = macoff; + table->sec_index = IDX_debug_macinfo; + table->line_offset = line_offset; + table->is_64bit = cudie->cu->address_size == 8; + table->comp_dir = __libdw_getcompdir (cudie); + + return table; +} + +static Dwarf_Macro_Op_Table * +get_table_for_offset (Dwarf *dbg, Dwarf_Word macoff, + const unsigned char *readp, + const unsigned char *const endp, + Dwarf_Die *cudie) +{ + const unsigned char *startp = readp; + + /* Request at least 3 bytes for header. */ + if (readp + 3 > endp) + { + invalid_dwarf: + __libdw_seterrno (DWARF_E_INVALID_DWARF); + return NULL; + } + + uint16_t version = read_2ubyte_unaligned_inc (dbg, readp); + if (version != 4) + { + __libdw_seterrno (DWARF_E_INVALID_VERSION); + return NULL; + } + + uint8_t flags = *readp++; + bool is_64bit = (flags & 0x1) != 0; + + Dwarf_Off line_offset = (Dwarf_Off) -1; + if ((flags & 0x2) != 0) + { + line_offset = read_addr_unaligned_inc (is_64bit ? 8 : 4, dbg, readp); + if (readp > endp) + goto invalid_dwarf; + } + else if (cudie != NULL) + { + Dwarf_Attribute attr_mem, *attr + = INTUSE(dwarf_attr) (cudie, DW_AT_stmt_list, &attr_mem); + if (attr != NULL) + INTUSE(dwarf_formudata) (attr, &line_offset); + } + + /* """The macinfo entry types defined in this standard may, but + might not, be described in the table""". + + I.e. these may be present. It's tempting to simply skip them, + but it's probably more correct to tolerate that a producer tweaks + the way certain opcodes are encoded, for whatever reasons. */ + + MACRO_PROTO (p_udata_str, DW_FORM_udata, DW_FORM_string); + MACRO_PROTO (p_udata_strp, DW_FORM_udata, DW_FORM_strp); + MACRO_PROTO (p_udata_udata, DW_FORM_udata, DW_FORM_udata); + MACRO_PROTO (p_secoffset, DW_FORM_sec_offset); + MACRO_PROTO (p_none); + + Dwarf_Macro_Op_Proto op_protos[255] = + { + [DW_MACRO_GNU_define - 1] = p_udata_str, + [DW_MACRO_GNU_undef - 1] = p_udata_str, + [DW_MACRO_GNU_define_indirect - 1] = p_udata_strp, + [DW_MACRO_GNU_undef_indirect - 1] = p_udata_strp, + [DW_MACRO_GNU_start_file - 1] = p_udata_udata, + [DW_MACRO_GNU_end_file - 1] = p_none, + [DW_MACRO_GNU_transparent_include - 1] = p_secoffset, + /* N.B. DW_MACRO_undef_indirectx, DW_MACRO_define_indirectx + should be added when 130313.1 is supported. */ + }; + + if ((flags & 0x4) != 0) + { + unsigned count = *readp++; + for (unsigned i = 0; i < count; ++i) + { + unsigned opcode = *readp++; + + Dwarf_Macro_Op_Proto e; + if (readp >= endp) + goto invalid; + get_uleb128 (e.nforms, readp, endp); + e.forms = readp; + op_protos[opcode - 1] = e; + + readp += e.nforms; + if (readp > endp) + { + invalid: + __libdw_seterrno (DWARF_E_INVALID_DWARF); + return NULL; + } + } + } + + size_t ct = 0; + for (unsigned i = 1; i < 256; ++i) + if (op_protos[i - 1].forms != NULL) + ++ct; + + /* We support at most 0xfe opcodes defined in the table, as 0xff is + a value that means that given opcode is not stored at all. But + that should be fine, as opcode 0 is not allocated. */ + assert (ct < 0xff); + + size_t macop_table_size = offsetof (Dwarf_Macro_Op_Table, table[ct]); + + Dwarf_Macro_Op_Table *table = libdw_alloc (dbg, Dwarf_Macro_Op_Table, + macop_table_size, 1); + + *table = (Dwarf_Macro_Op_Table) { + .offset = macoff, + .sec_index = IDX_debug_macro, + .line_offset = line_offset, + .header_len = readp - startp, + .version = version, + .is_64bit = is_64bit, + + /* NULL if CUDIE is NULL or DW_AT_comp_dir is absent. */ + .comp_dir = __libdw_getcompdir (cudie), + }; + build_table (table, op_protos); + + return table; +} + +static Dwarf_Macro_Op_Table * +cache_op_table (Dwarf *dbg, int sec_index, Dwarf_Off macoff, + const unsigned char *startp, + const unsigned char *const endp, + Dwarf_Die *cudie) +{ + Dwarf_Macro_Op_Table fake = { .offset = macoff, .sec_index = sec_index }; + Dwarf_Macro_Op_Table **found = tfind (&fake, &dbg->macro_ops, + macro_op_compare); + if (found != NULL) + return *found; + + Dwarf_Macro_Op_Table *table = sec_index == IDX_debug_macro + ? get_table_for_offset (dbg, macoff, startp, endp, cudie) + : get_macinfo_table (dbg, macoff, cudie); + + if (table == NULL) + return NULL; + + Dwarf_Macro_Op_Table **ret = tsearch (table, &dbg->macro_ops, + macro_op_compare); + if (unlikely (ret == NULL)) + { + __libdw_seterrno (DWARF_E_NOMEM); + return NULL; + } + + return *ret; +} + +static ptrdiff_t +read_macros (Dwarf *dbg, int sec_index, + Dwarf_Off macoff, int (*callback) (Dwarf_Macro *, void *), + void *arg, ptrdiff_t offset, bool accept_0xff, + Dwarf_Die *cudie) +{ + Elf_Data *d = dbg->sectiondata[sec_index]; + if (unlikely (d == NULL || d->d_buf == NULL)) + { + __libdw_seterrno (DWARF_E_NO_ENTRY); + return -1; + } + + if (unlikely (macoff >= d->d_size)) + { + __libdw_seterrno (DWARF_E_INVALID_DWARF); + return -1; + } + + const unsigned char *const startp = d->d_buf + macoff; + const unsigned char *const endp = d->d_buf + d->d_size; + + Dwarf_Macro_Op_Table *table = cache_op_table (dbg, sec_index, macoff, + startp, endp, cudie); + if (table == NULL) + return -1; + + if (offset == 0) + offset = table->header_len; + + assert (offset >= 0); + assert (offset < endp - startp); + const unsigned char *readp = startp + offset; + + while (readp < endp) + { + unsigned int opcode = *readp++; + if (opcode == 0) + /* Nothing more to do. */ + return 0; + + if (unlikely (opcode == 0xff && ! accept_0xff)) + { + /* See comment below at dwarf_getmacros for explanation of + why we are doing this. */ + __libdw_seterrno (DWARF_E_INVALID_OPCODE); + return -1; + } + + unsigned int idx = table->opcodes[opcode - 1]; + if (idx == 0xff) + { + __libdw_seterrno (DWARF_E_INVALID_OPCODE); + return -1; + } + + Dwarf_Macro_Op_Proto *proto = &table->table[idx]; + + /* A fake CU with bare minimum data to fool dwarf_formX into + doing the right thing with the attributes that we put out. + We arbitrarily pretend it's version 4. */ + Dwarf_CU fake_cu = { + .dbg = dbg, + .version = 4, + .offset_size = table->is_64bit ? 8 : 4, + .startp = (void *) startp + offset, + .endp = (void *) endp, + }; + + Dwarf_Attribute attributes[proto->nforms]; + for (Dwarf_Word i = 0; i < proto->nforms; ++i) + { + /* We pretend this is a DW_AT_GNU_macros attribute so that + DW_FORM_sec_offset forms get correctly interpreted as + offset into .debug_macro. */ + attributes[i].code = DW_AT_GNU_macros; + attributes[i].form = proto->forms[i]; + attributes[i].valp = (void *) readp; + attributes[i].cu = &fake_cu; + + size_t len = __libdw_form_val_len (&fake_cu, proto->forms[i], readp); + if (len == (size_t) -1) + return -1; + + readp += len; + } + + Dwarf_Macro macro = { + .table = table, + .opcode = opcode, + .attributes = attributes, + }; + + if (callback (¯o, arg) != DWARF_CB_OK) + return readp - startp; + } + + return 0; +} + +/* Token layout: + + - The highest bit is used for distinguishing between callers that + know that opcode 0xff may have one of two incompatible meanings. + The mask that we use for selecting this bit is + DWARF_GETMACROS_START. + + - The rest of the token (31 or 63 bits) encodes address inside the + macro unit. + + Besides, token value of 0 signals end of iteration and -1 is + reserved for signaling errors. That means it's impossible to + represent maximum offset of a .debug_macro unit to new-style + callers (which in practice decreases the permissible macro unit + size by another 1 byte). */ + +static ptrdiff_t +token_from_offset (ptrdiff_t offset, bool accept_0xff) +{ + if (offset == -1 || offset == 0) + return offset; + + /* Make sure the offset didn't overflow into the flag bit. */ + if ((offset & DWARF_GETMACROS_START) != 0) + { + __libdw_seterrno (DWARF_E_TOO_BIG); + return -1; + } + + if (accept_0xff) + offset |= DWARF_GETMACROS_START; + + return offset; +} + +static ptrdiff_t +offset_from_token (ptrdiff_t token, bool *accept_0xffp) +{ + *accept_0xffp = (token & DWARF_GETMACROS_START) != 0; + token &= ~DWARF_GETMACROS_START; + + return token; +} + +static ptrdiff_t +gnu_macros_getmacros_off (Dwarf *dbg, Dwarf_Off macoff, + int (*callback) (Dwarf_Macro *, void *), + void *arg, ptrdiff_t offset, bool accept_0xff, + Dwarf_Die *cudie) +{ + assert (offset >= 0); + + if (macoff >= dbg->sectiondata[IDX_debug_macro]->d_size) + { + __libdw_seterrno (DWARF_E_INVALID_OFFSET); + return -1; + } + + return read_macros (dbg, IDX_debug_macro, macoff, + callback, arg, offset, accept_0xff, cudie); +} + +static ptrdiff_t +macro_info_getmacros_off (Dwarf *dbg, Dwarf_Off macoff, + int (*callback) (Dwarf_Macro *, void *), + void *arg, ptrdiff_t offset, Dwarf_Die *cudie) +{ + assert (offset >= 0); + + return read_macros (dbg, IDX_debug_macinfo, macoff, + callback, arg, offset, true, cudie); +} + +ptrdiff_t +dwarf_getmacros_off (Dwarf *dbg, Dwarf_Off macoff, + int (*callback) (Dwarf_Macro *, void *), + void *arg, ptrdiff_t token) +{ + if (dbg == NULL) + { + __libdw_seterrno (DWARF_E_NO_DWARF); + return -1; + } + + bool accept_0xff; + ptrdiff_t offset = offset_from_token (token, &accept_0xff); + assert (accept_0xff); + + offset = gnu_macros_getmacros_off (dbg, macoff, callback, arg, offset, + accept_0xff, NULL); + + return token_from_offset (offset, accept_0xff); +} + +ptrdiff_t +dwarf_getmacros (cudie, callback, arg, token) + Dwarf_Die *cudie; + int (*callback) (Dwarf_Macro *, void *); + void *arg; + ptrdiff_t token; +{ + if (cudie == NULL) + { + __libdw_seterrno (DWARF_E_NO_DWARF); + return -1; + } + + /* This function might be called from a code that expects to see + DW_MACINFO_* opcodes, not DW_MACRO_{GNU_,}* ones. It is fine to + serve most DW_MACRO_{GNU_,}* opcodes to such code, because those + whose values are the same as DW_MACINFO_* ones also have the same + behavior. It is not very likely that a .debug_macro section + would only use the part of opcode space that it shares with + .debug_macinfo, but it is possible. Serving the opcodes that are + only valid in DW_MACRO_{GNU_,}* domain is OK as well, because + clients in general need to be ready that newer standards define + more opcodes, and have coping mechanisms for unfamiliar opcodes. + + The one exception to the above rule is opcode 0xff, which has + concrete semantics in .debug_macinfo, but falls into vendor block + in .debug_macro, and can be assigned to do whatever. There is + some small probability that the two opcodes would look + superficially similar enough that a client would be confused and + misbehave as a result. For this reason, we refuse to serve + through this interface 0xff's originating from .debug_macro + unless the TOKEN that we obtained indicates the call originates + from a new-style caller. See above for details on what + information is encoded into tokens. */ + + bool accept_0xff; + ptrdiff_t offset = offset_from_token (token, &accept_0xff); + + /* DW_AT_macro_info */ + if (dwarf_hasattr (cudie, DW_AT_macro_info)) + { + Dwarf_Word macoff; + if (get_offset_from (cudie, DW_AT_macro_info, &macoff) != 0) + return -1; + offset = macro_info_getmacros_off (cudie->cu->dbg, macoff, + callback, arg, offset, cudie); + } + else + { + /* DW_AT_GNU_macros, DW_AT_macros */ + Dwarf_Word macoff; + if (get_offset_from (cudie, DW_AT_GNU_macros, &macoff) != 0) + return -1; + offset = gnu_macros_getmacros_off (cudie->cu->dbg, macoff, + callback, arg, offset, accept_0xff, + cudie); + } + + return token_from_offset (offset, accept_0xff); +} |