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osandovosandov
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libdrgn: dwarf_index: move bswap from file to compilation unit
Remove an indirection.
1 parent 1c9ab2e commit a9a2cb7

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2 files changed

+32
-41
lines changed

2 files changed

+32
-41
lines changed

‎libdrgn/dwarf_index.c‎

Lines changed: 32 additions & 39 deletions
Original file line numberDiff line numberDiff line change
@@ -121,6 +121,7 @@ struct compilation_unit {
121121
uint64_t debug_abbrev_offset;
122122
uint8_t address_size;
123123
bool is_64_bit;
124+
bool bswap;
124125
};
125126

126127
static inline const char *section_ptr(Elf_Data *data, size_t offset)
@@ -302,10 +303,6 @@ static struct drgn_error *read_sections(struct drgn_dwarf_index_file *file)
302303
if (!ehdr)
303304
return &drgn_not_elf;
304305

305-
file->bswap = (ehdr->e_ident[EI_DATA] !=
306-
(__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ?
307-
ELFDATA2LSB : ELFDATA2MSB));
308-
309306
if (elf_getshdrstrndx(file->elf, &shstrndx))
310307
return drgn_error_libelf();
311308

@@ -650,17 +647,17 @@ static struct drgn_error *read_compilation_unit_header(const char *ptr,
650647
uint32_t tmp;
651648
uint16_t version;
652649

653-
if (!read_u32(&ptr, end, cu->file->bswap, &tmp))
650+
if (!read_u32(&ptr, end, cu->bswap, &tmp))
654651
return drgn_eof();
655652
cu->is_64_bit = tmp == UINT32_C(0xffffffff);
656653
if (cu->is_64_bit) {
657-
if (!read_u64(&ptr, end, cu->file->bswap, &cu->unit_length))
654+
if (!read_u64(&ptr, end, cu->bswap, &cu->unit_length))
658655
return drgn_eof();
659656
} else {
660657
cu->unit_length = tmp;
661658
}
662659

663-
if (!read_u16(&ptr, end, cu->file->bswap, &version))
660+
if (!read_u16(&ptr, end, cu->bswap, &version))
664661
return drgn_eof();
665662
if (version != 2 && version != 3 && version != 4) {
666663
return drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
@@ -669,11 +666,10 @@ static struct drgn_error *read_compilation_unit_header(const char *ptr,
669666
}
670667

671668
if (cu->is_64_bit) {
672-
if (!read_u64(&ptr, end, cu->file->bswap,
673-
&cu->debug_abbrev_offset))
669+
if (!read_u64(&ptr, end, cu->bswap, &cu->debug_abbrev_offset))
674670
return drgn_eof();
675671
} else {
676-
if (!read_u32_into_u64(&ptr, end, cu->file->bswap,
672+
if (!read_u32_into_u64(&ptr, end, cu->bswap,
677673
&cu->debug_abbrev_offset))
678674
return drgn_eof();
679675
}
@@ -689,10 +685,15 @@ static struct drgn_error *read_cus(struct drgn_dwarf_index_file *file,
689685
size_t *num_cus, size_t *cus_capacity)
690686
{
691687
struct drgn_error *err;
688+
bool bswap;
692689
Elf_Data *debug_info = file->sections[SECTION_DEBUG_INFO];
693690
const char *ptr = section_ptr(debug_info, 0);
694691
const char *end = section_end(debug_info);
695692

693+
bswap = (elf_getident(file->elf, NULL)[EI_DATA] !=
694+
(__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ?
695+
ELFDATA2LSB : ELFDATA2MSB));
696+
696697
while (ptr < end) {
697698
struct compilation_unit *cu;
698699

@@ -711,6 +712,7 @@ static struct drgn_error *read_cus(struct drgn_dwarf_index_file *file,
711712
cu = &(*cus)[(*num_cus)++];
712713
cu->file = file;
713714
cu->ptr = ptr;
715+
cu->bswap = bswap;
714716
if ((err = read_compilation_unit_header(ptr, end, cu)))
715717
return err;
716718

@@ -1008,21 +1010,21 @@ static struct drgn_error *read_abbrev_table(const char *ptr, const char *end,
10081010
return NULL;
10091011
}
10101012

1011-
static struct drgn_error *skip_lnp_header(struct drgn_dwarf_index_file *file,
1013+
static struct drgn_error *skip_lnp_header(struct compilation_unit *cu,
10121014
const char **ptr, const char *end)
10131015
{
10141016
uint32_t tmp;
10151017
bool is_64_bit;
10161018
uint16_t version;
10171019
uint8_t opcode_base;
10181020

1019-
if (!read_u32(ptr, end, file->bswap, &tmp))
1021+
if (!read_u32(ptr, end, cu->bswap, &tmp))
10201022
return drgn_eof();
10211023
is_64_bit = tmp == UINT32_C(0xffffffff);
10221024
if (is_64_bit)
10231025
*ptr += sizeof(uint64_t);
10241026

1025-
if (!read_u16(ptr, end, file->bswap, &version))
1027+
if (!read_u16(ptr, end, cu->bswap, &version))
10261028
return drgn_eof();
10271029
if (version != 2 && version != 3 && version != 4) {
10281030
return drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
@@ -1091,7 +1093,8 @@ read_file_name_table(struct drgn_dwarf_index *dindex,
10911093

10921094
siphash_vector_init(&directories);
10931095

1094-
if ((err = skip_lnp_header(file, &ptr, end)))
1096+
err = skip_lnp_header(cu, &ptr, end);
1097+
if (err)
10951098
return err;
10961099

10971100
for (;;) {
@@ -1285,13 +1288,11 @@ static struct drgn_error *read_die(struct compilation_unit *cu,
12851288
return drgn_eof();
12861289
goto skip;
12871290
case ATTRIB_BLOCK2:
1288-
if (!read_u16_into_size_t(ptr, end, cu->file->bswap,
1289-
&skip))
1291+
if (!read_u16_into_size_t(ptr, end, cu->bswap, &skip))
12901292
return drgn_eof();
12911293
goto skip;
12921294
case ATTRIB_BLOCK4:
1293-
if (!read_u32_into_size_t(ptr, end, cu->file->bswap,
1294-
&skip))
1295+
if (!read_u32_into_size_t(ptr, end, cu->bswap, &skip))
12951296
return drgn_eof();
12961297
goto skip;
12971298
case ATTRIB_EXPRLOC:
@@ -1314,18 +1315,15 @@ static struct drgn_error *read_die(struct compilation_unit *cu,
13141315
return drgn_eof();
13151316
goto sibling;
13161317
case ATTRIB_SIBLING_REF2:
1317-
if (!read_u16_into_size_t(ptr, end, cu->file->bswap,
1318-
&tmp))
1318+
if (!read_u16_into_size_t(ptr, end, cu->bswap, &tmp))
13191319
return drgn_eof();
13201320
goto sibling;
13211321
case ATTRIB_SIBLING_REF4:
1322-
if (!read_u32_into_size_t(ptr, end, cu->file->bswap,
1323-
&tmp))
1322+
if (!read_u32_into_size_t(ptr, end, cu->bswap, &tmp))
13241323
return drgn_eof();
13251324
goto sibling;
13261325
case ATTRIB_SIBLING_REF8:
1327-
if (!read_u64_into_size_t(ptr, end, cu->file->bswap,
1328-
&tmp))
1326+
if (!read_u64_into_size_t(ptr, end, cu->bswap, &tmp))
13291327
return drgn_eof();
13301328
goto sibling;
13311329
case ATTRIB_SIBLING_REF_UDATA:
@@ -1338,13 +1336,11 @@ static struct drgn_error *read_die(struct compilation_unit *cu,
13381336
__builtin_prefetch(die->sibling);
13391337
break;
13401338
case ATTRIB_NAME_STRP4:
1341-
if (!read_u32_into_size_t(ptr, end, cu->file->bswap,
1342-
&tmp))
1339+
if (!read_u32_into_size_t(ptr, end, cu->bswap, &tmp))
13431340
return drgn_eof();
13441341
goto strp;
13451342
case ATTRIB_NAME_STRP8:
1346-
if (!read_u64_into_size_t(ptr, end, cu->file->bswap,
1347-
&tmp))
1343+
if (!read_u64_into_size_t(ptr, end, cu->bswap, &tmp))
13481344
return drgn_eof();
13491345
strp:
13501346
if (!read_in_bounds(debug_str_buffer, debug_str_end,
@@ -1354,12 +1350,12 @@ static struct drgn_error *read_die(struct compilation_unit *cu,
13541350
__builtin_prefetch(die->name);
13551351
break;
13561352
case ATTRIB_STMT_LIST_LINEPTR4:
1357-
if (!read_u32_into_size_t(ptr, end, cu->file->bswap,
1353+
if (!read_u32_into_size_t(ptr, end, cu->bswap,
13581354
&die->stmt_list))
13591355
return drgn_eof();
13601356
break;
13611357
case ATTRIB_STMT_LIST_LINEPTR8:
1362-
if (!read_u64_into_size_t(ptr, end, cu->file->bswap,
1358+
if (!read_u64_into_size_t(ptr, end, cu->bswap,
13631359
&die->stmt_list))
13641360
return drgn_eof();
13651361
break;
@@ -1368,17 +1364,17 @@ static struct drgn_error *read_die(struct compilation_unit *cu,
13681364
return drgn_eof();
13691365
break;
13701366
case ATTRIB_DECL_FILE_DATA2:
1371-
if (!read_u16_into_size_t(ptr, end, cu->file->bswap,
1367+
if (!read_u16_into_size_t(ptr, end, cu->bswap,
13721368
&die->decl_file))
13731369
return drgn_eof();
13741370
break;
13751371
case ATTRIB_DECL_FILE_DATA4:
1376-
if (!read_u32_into_size_t(ptr, end, cu->file->bswap,
1372+
if (!read_u32_into_size_t(ptr, end, cu->bswap,
13771373
&die->decl_file))
13781374
return drgn_eof();
13791375
break;
13801376
case ATTRIB_DECL_FILE_DATA8:
1381-
if (!read_u64_into_size_t(ptr, end, cu->file->bswap,
1377+
if (!read_u64_into_size_t(ptr, end, cu->bswap,
13821378
&die->decl_file))
13831379
return drgn_eof();
13841380
break;
@@ -1392,18 +1388,15 @@ static struct drgn_error *read_die(struct compilation_unit *cu,
13921388
return drgn_eof();
13931389
goto specification;
13941390
case ATTRIB_SPECIFICATION_REF2:
1395-
if (!read_u16_into_size_t(ptr, end, cu->file->bswap,
1396-
&tmp))
1391+
if (!read_u16_into_size_t(ptr, end, cu->bswap, &tmp))
13971392
return drgn_eof();
13981393
goto specification;
13991394
case ATTRIB_SPECIFICATION_REF4:
1400-
if (!read_u32_into_size_t(ptr, end, cu->file->bswap,
1401-
&tmp))
1395+
if (!read_u32_into_size_t(ptr, end, cu->bswap, &tmp))
14021396
return drgn_eof();
14031397
goto specification;
14041398
case ATTRIB_SPECIFICATION_REF8:
1405-
if (!read_u64_into_size_t(ptr, end, cu->file->bswap,
1406-
&tmp))
1399+
if (!read_u64_into_size_t(ptr, end, cu->bswap, &tmp))
14071400
return drgn_eof();
14081401
goto specification;
14091402
case ATTRIB_SPECIFICATION_REF_UDATA:

‎libdrgn/dwarf_index.h‎

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -55,8 +55,6 @@ enum {
5555

5656
struct drgn_dwarf_index_file {
5757
Elf_Data *sections[DRGN_DWARF_INDEX_NUM_SECTIONS];
58-
/* Other byte order. */
59-
bool bswap;
6058
bool failed;
6159
int fd;
6260
/*

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