446 changes: 356 additions & 90 deletions lldb/tools/compact-unwind/compact-unwind-dumper.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
#include <sys/stat.h>
#include <inttypes.h>
#include <stdio.h>
#include <mach-o/nlist.h>

#define EXTRACT_BITS(value, mask) \
( (value >> __builtin_ctz(mask)) & (((1 << __builtin_popcount(mask)))-1) )
Expand All @@ -23,6 +24,18 @@
// can dump at least the UNWIND_X86_64_MODE_RBP_FRAME format entries
// correctly.

struct symbol
{
uint64_t file_address;
const char *name;
};

int
symbol_compare (const void *a, const void *b)
{
return (int) ((struct symbol *)a)->file_address - ((struct symbol *)b)->file_address;
}

struct baton
{
cpu_type_t cputype;
Expand All @@ -38,27 +51,55 @@ struct baton
uint64_t text_section_vmaddr; // __TEXT,__text section vmaddr
uint64_t text_section_file_offset;

uint8_t *text_section_start; // pointer into this program's address space

uint64_t eh_section_file_address; // the file address of the __TEXT,__eh_frame section

uint8_t *lsda_array_start; // for the currently-being-processed first-level index
uint8_t *lsda_array_end; // the lsda_array_start for the NEXT first-level index

struct symbol *symbols;
int symbols_count;

uint64_t *function_start_addresses;
int function_start_addresses_count;

int current_index_table_number;

struct unwind_info_section_header unwind_header;
struct unwind_info_section_header_index_entry first_level_index_entry;
struct unwind_info_compressed_second_level_page_header compressed_second_level_page_header;
struct unwind_info_regular_second_level_page_header regular_second_level_page_header;
};


uint64_t
read_leb128 (uint8_t **offset)
{
uint64_t result = 0;
int shift = 0;
while (1)
{
uint8_t byte = **offset;
*offset = *offset + 1;
result |= (byte & 0x7f) << shift;
if ((byte & 0x80) == 0)
break;
shift += 7;
}

return result;
}

// step through the load commands in a thin mach-o binary,
// find the cputype and the start of the __TEXT,__unwind_info
// section, return a pointer to that section or NULL if not found.

void
static void
scan_macho_load_commands (struct baton *baton)
{
struct symtab_command symtab_cmd;
uint64_t linkedit_segment_vmaddr;
uint64_t linkedit_segment_file_offset;

baton->compact_unwind_start = 0;

uint32_t *magic = (uint32_t *) baton->mach_header_start;
Expand Down Expand Up @@ -89,119 +130,295 @@ scan_macho_load_commands (struct baton *baton)

baton->cputype = mh.cputype;

uint8_t *start_of_load_commands = offset;

uint32_t cur_cmd = 0;
while (cur_cmd < mh.ncmds && (offset - baton->mach_header_start) < mh.sizeofcmds)
while (cur_cmd < mh.ncmds && (offset - start_of_load_commands) < mh.sizeofcmds)
{
struct load_command lc;
uint32_t *lc_cmd = (uint32_t *) offset;
uint32_t *lc_cmdsize = (uint32_t *) offset + 1;
uint8_t *start_of_this_load_cmd = offset;

char segment_name[17];
segment_name[0] = '\0';
uint32_t nsects = 0;
uint64_t segment_offset = 0;
uint64_t segment_vmaddr = 0;

if (*lc_cmd == LC_SEGMENT_64)
{
struct segment_command_64 seg;
memcpy (&seg, offset, sizeof (struct segment_command_64));
memcpy (&segment_name, &seg.segname, 16);
segment_name[16] = '\0';
nsects = seg.nsects;
segment_offset = seg.fileoff;
segment_vmaddr = seg.vmaddr;
offset += sizeof (struct segment_command_64);
}

if (*lc_cmd == LC_SEGMENT)
if (*lc_cmd == LC_SEGMENT || *lc_cmd == LC_SEGMENT_64)
{
struct segment_command seg;
memcpy (&seg, offset, sizeof (struct segment_command));
memcpy (&segment_name, &seg.segname, 16);
segment_name[16] = '\0';
nsects = seg.nsects;
segment_offset = seg.fileoff;
segment_vmaddr = seg.vmaddr;
offset += sizeof (struct segment_command);
}
char segment_name[17];
segment_name[0] = '\0';
uint32_t nsects = 0;
uint64_t segment_offset = 0;
uint64_t segment_vmaddr = 0;

if ((*lc_cmd == LC_SEGMENT || *lc_cmd == LC_SEGMENT_64)
&& nsects != 0 && segment_name[0] != '\0' && strcmp (segment_name, "__TEXT") == 0)
{
baton->text_segment_vmaddr = segment_vmaddr;
baton->text_segment_file_offset = segment_offset;
if (*lc_cmd == LC_SEGMENT_64)
{
struct segment_command_64 seg;
memcpy (&seg, offset, sizeof (struct segment_command_64));
memcpy (&segment_name, &seg.segname, 16);
segment_name[16] = '\0';
nsects = seg.nsects;
segment_offset = seg.fileoff;
segment_vmaddr = seg.vmaddr;
offset += sizeof (struct segment_command_64);
}

uint32_t current_sect = 0;
while (current_sect < nsects && (offset - start_of_this_load_cmd) < *lc_cmdsize)
if (*lc_cmd == LC_SEGMENT)
{
char sect_name[17];
memcpy (&sect_name, offset, 16);
sect_name[16] = '\0';
if (strcmp (sect_name, "__unwind_info") == 0)
struct segment_command seg;
memcpy (&seg, offset, sizeof (struct segment_command));
memcpy (&segment_name, &seg.segname, 16);
segment_name[16] = '\0';
nsects = seg.nsects;
segment_offset = seg.fileoff;
segment_vmaddr = seg.vmaddr;
offset += sizeof (struct segment_command);
}

if (nsects != 0 && strcmp (segment_name, "__TEXT") == 0)
{
baton->text_segment_vmaddr = segment_vmaddr;
baton->text_segment_file_offset = segment_offset;

uint32_t current_sect = 0;
while (current_sect < nsects && (offset - start_of_this_load_cmd) < *lc_cmdsize)
{
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->compact_unwind_start = baton->mach_header_start + sect.offset;
}
else
char sect_name[17];
memcpy (&sect_name, offset, 16);
sect_name[16] = '\0';
if (strcmp (sect_name, "__unwind_info") == 0)
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->compact_unwind_start = baton->mach_header_start + sect.offset;
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->compact_unwind_start = baton->mach_header_start + sect.offset;
}
else
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->compact_unwind_start = baton->mach_header_start + sect.offset;
}
}
}
if (strcmp (sect_name, "__eh_frame") == 0)
{
if (is_64bit)
if (strcmp (sect_name, "__eh_frame") == 0)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->eh_section_file_address = sect.addr;
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->eh_section_file_address = sect.addr;
}
else
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->eh_section_file_address = sect.addr;
}
}
else
if (strcmp (sect_name, "__text") == 0)
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->eh_section_file_address = sect.addr;
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->text_section_vmaddr = sect.addr;
baton->text_section_file_offset = sect.offset;
}
else
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->text_section_vmaddr = sect.addr;
}
}
}
if (strcmp (sect_name, "__text") == 0)
{
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->text_section_vmaddr = sect.addr;
baton->text_section_file_offset = sect.offset;
offset += sizeof (struct section_64);
}
else
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->text_section_vmaddr = sect.addr;
offset += sizeof (struct section);
}
}
}

if (strcmp (segment_name, "__LINKEDIT") == 0)
{
linkedit_segment_vmaddr = segment_vmaddr;
linkedit_segment_file_offset = segment_offset;
}
}

if (*lc_cmd == LC_SYMTAB)
{
memcpy (&symtab_cmd, offset, sizeof (struct symtab_command));
}

if (*lc_cmd == LC_DYSYMTAB)
{
struct dysymtab_command dysymtab_cmd;
memcpy (&dysymtab_cmd, offset, sizeof (struct dysymtab_command));

int nlist_size = 12;
if (is_64bit)
nlist_size = 16;

char *string_table = (char *) (baton->mach_header_start + symtab_cmd.stroff);
uint8_t *local_syms = baton->mach_header_start + symtab_cmd.symoff + (dysymtab_cmd.ilocalsym * nlist_size);
int local_syms_count = dysymtab_cmd.nlocalsym;
uint8_t *exported_syms = baton->mach_header_start + symtab_cmd.symoff + (dysymtab_cmd.iextdefsym * nlist_size);
int exported_syms_count = dysymtab_cmd.nextdefsym;

// We're only going to create records for a small number of these symbols but to
// simplify the memory management I'll allocate enough space to store all of them.
baton->symbols = (struct symbol *) malloc (sizeof (struct symbol) * (local_syms_count + exported_syms_count));
baton->symbols_count = 0;

for (int i = 0; i < local_syms_count; i++)
{
struct nlist_64 nlist;
if (is_64bit)
{
memcpy (&nlist, local_syms + (i * nlist_size), sizeof (struct nlist_64));
}
else
{
struct nlist nlist_32;
memcpy (&nlist_32, local_syms + (i * nlist_size), sizeof (struct nlist));
nlist.n_un.n_strx = nlist_32.n_un.n_strx;
nlist.n_type = nlist_32.n_type;
nlist.n_sect = nlist_32.n_sect;
nlist.n_desc = nlist_32.n_desc;
nlist.n_value = nlist_32.n_value;
}
if ((nlist.n_type & N_STAB) == 0
&& ((nlist.n_type & N_EXT) == 1 ||
((nlist.n_type & N_TYPE) == N_TYPE && nlist.n_sect != NO_SECT))
&& nlist.n_value != 0
&& nlist.n_value != baton->text_segment_vmaddr)
{
baton->symbols[baton->symbols_count].file_address = nlist.n_value;
baton->symbols[baton->symbols_count].name = string_table + nlist.n_un.n_strx;
baton->symbols_count++;
}
}

for (int i = 0; i < exported_syms_count; i++)
{
struct nlist_64 nlist;
if (is_64bit)
{
offset += sizeof (struct section_64);
memcpy (&nlist, exported_syms + (i * nlist_size), sizeof (struct nlist_64));
}
else
{
offset += sizeof (struct section);
struct nlist nlist_32;
memcpy (&nlist_32, exported_syms + (i * nlist_size), sizeof (struct nlist));
nlist.n_un.n_strx = nlist_32.n_un.n_strx;
nlist.n_type = nlist_32.n_type;
nlist.n_sect = nlist_32.n_sect;
nlist.n_desc = nlist_32.n_desc;
nlist.n_value = nlist_32.n_value;
}
if ((nlist.n_type & N_STAB) == 0
&& ((nlist.n_type & N_EXT) == 1 ||
((nlist.n_type & N_TYPE) == N_TYPE && nlist.n_sect != NO_SECT))
&& nlist.n_value != 0
&& nlist.n_value != baton->text_segment_vmaddr)
{
baton->symbols[baton->symbols_count].file_address = nlist.n_value;
baton->symbols[baton->symbols_count].name = string_table + nlist.n_un.n_strx;
baton->symbols_count++;
}
}

return;
qsort (baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);
}

if (*lc_cmd == LC_FUNCTION_STARTS)
{
struct linkedit_data_command function_starts_cmd;
memcpy (&function_starts_cmd, offset, sizeof (struct linkedit_data_command));

uint8_t *funcstarts_offset = baton->mach_header_start + function_starts_cmd.dataoff;
uint8_t *function_end = funcstarts_offset + function_starts_cmd.datasize;
int count = 0;

while (funcstarts_offset < function_end)
{
if (read_leb128 (&funcstarts_offset) != 0)
{
count++;
}
}

baton->function_start_addresses = (uint64_t *) malloc (sizeof (uint64_t) * count);
baton->function_start_addresses_count = count;

funcstarts_offset = baton->mach_header_start + function_starts_cmd.dataoff;
uint64_t current_pc = baton->text_segment_vmaddr;
int i = 0;
while (funcstarts_offset < function_end)
{
uint64_t func_start = read_leb128 (&funcstarts_offset);
if (func_start != 0)
{
current_pc += func_start;
baton->function_start_addresses[i++] = current_pc;
}
}
}

offset = start_of_this_load_cmd + *lc_cmdsize;
cur_cmd++;
}


// Augment the symbol table with the function starts table -- adding symbol entries
// for functions that were stripped.

int unnamed_functions_to_add = 0;
for (int i = 0; i < baton->function_start_addresses_count; i++)
{
struct symbol search_key;
search_key.file_address = baton->function_start_addresses[i];
struct symbol *sym = bsearch (&search_key, baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);
if (sym == NULL)
unnamed_functions_to_add++;
}

baton->symbols = (struct symbol *) realloc (baton->symbols, sizeof (struct symbol) * (baton->symbols_count + unnamed_functions_to_add));

int current_unnamed_symbol = 1;
int number_symbols_added = 0;
for (int i = 0; i < baton->function_start_addresses_count; i++)
{
struct symbol search_key;
search_key.file_address = baton->function_start_addresses[i];
struct symbol *sym = bsearch (&search_key, baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);
if (sym == NULL)
{
char *name;
asprintf (&name, "unnamed function #%d", current_unnamed_symbol++);
baton->symbols[baton->symbols_count + number_symbols_added].file_address = baton->function_start_addresses[i];
baton->symbols[baton->symbols_count + number_symbols_added].name = name;
number_symbols_added++;
}
}
baton->symbols_count += number_symbols_added;
qsort (baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);


// printf ("function start addresses\n");
// for (int i = 0; i < baton->function_start_addresses_count; i++)
// {
// printf ("0x%012llx\n", baton->function_start_addresses[i]);
// }

// printf ("symbol table names & addresses\n");
// for (int i = 0; i < baton->symbols_count; i++)
// {
// printf ("0x%012llx %s\n", baton->symbols[i].file_address, baton->symbols[i].name);
// }

}

void
Expand All @@ -212,7 +429,7 @@ print_encoding_x86_64 (struct baton baton, uint8_t *function_start, uint32_t enc
{
case UNWIND_X86_64_MODE_RBP_FRAME:
{
printf (" - frame func: CFA is rbp+%d ", 16);
printf ("frame func: CFA is rbp+%d ", 16);
printf (" rip=[CFA-8] rbp=[CFA-16]");
uint32_t saved_registers_offset = EXTRACT_BITS (encoding, UNWIND_X86_64_RBP_FRAME_OFFSET);

Expand Down Expand Up @@ -268,7 +485,7 @@ print_encoding_x86_64 (struct baton baton, uint8_t *function_start, uint32_t enc
stack_size += stack_adjust * 8;
}

printf (" frameless function: stack size %d, register count %d ", stack_size * 8, register_count);
printf ("frameless function: stack size %d, register count %d ", stack_size * 8, register_count);

if (register_count == 0)
{
Expand Down Expand Up @@ -406,7 +623,7 @@ print_encoding_x86_64 (struct baton baton, uint8_t *function_start, uint32_t enc
case UNWIND_X86_64_MODE_DWARF:
{
uint32_t dwarf_offset = encoding & UNWIND_X86_DWARF_SECTION_OFFSET;
printf (" use DWARF unwind instructions: FDE at offset %d (file address 0x%" PRIx64 ")",
printf ("DWARF unwind instructions: FDE at offset %d (file address 0x%" PRIx64 ")",
dwarf_offset, dwarf_offset + baton.eh_section_file_address);
}
break;
Expand Down Expand Up @@ -445,12 +662,53 @@ print_function_encoding (struct baton baton, uint32_t idx, uint32_t encoding, ui
{
asprintf (&entry_encoding_index_str, "");
}
printf (" func [%d] offset %d (file addr 0x%" PRIx64 ")%s - 0x%x",

uint64_t file_address = baton.first_level_index_entry.functionOffset + entry_func_offset + baton.text_segment_vmaddr;

printf (" func [%d] offset %d (file addr 0x%" PRIx64 ")%s, encoding is 0x%x",
idx, entry_func_offset,
baton.first_level_index_entry.functionOffset + entry_func_offset + baton.text_segment_vmaddr, // FIXME
file_address,
entry_encoding_index_str,
encoding);

struct symbol *symbol = NULL;
for (int i = 0; i < baton.symbols_count; i++)
{
if (i == baton.symbols_count - 1 && baton.symbols[i].file_address <= file_address)
{
symbol = &(baton.symbols[i]);
break;
}
else
{
if (baton.symbols[i].file_address <= file_address && baton.symbols[i + 1].file_address > file_address)
{
symbol = &(baton.symbols[i]);
break;
}
}
}

printf ("\n ");
if (symbol)
{
int offset = file_address - symbol->file_address;

// FIXME this is a poor heuristic - if we're greater than 16 bytes past the
// start of the function, this is the unwind info for a stripped function.
// In reality the compact unwind entry may not line up exactly with the
// function bounds.
if (offset >= 0)
{
printf ("name: %s", symbol->name);
if (offset > 0)
{
printf (" + %d", offset);
}
}
printf ("\n ");
}

print_encoding (baton, baton.mach_header_start + baton.first_level_index_entry.functionOffset + baton.text_section_file_offset + entry_func_offset, encoding);

bool has_lsda = encoding & UNWIND_HAS_LSDA;
Expand Down Expand Up @@ -497,7 +755,7 @@ print_function_encoding (struct baton baton, uint32_t idx, uint32_t encoding, ui

uint8_t **personality_addr = (uint8_t **) (baton.mach_header_start + pers_delta);
void *personality = *personality_addr;
printf (", personality func addr @ offset %d", pers_delta);
printf (", personality func offset %d", pers_delta);
// printf (", personality %p", personality);
}

Expand Down Expand Up @@ -563,15 +821,15 @@ print_second_level_index_compressed (struct baton baton)
}

void
print_second_level_index (struct baton baton, uint32_t second_level_index_count)
print_second_level_index (struct baton baton)
{
uint8_t *index_start = baton.compact_unwind_start + baton.first_level_index_entry.secondLevelPagesSectionOffset;

if ((*(uint32_t*) index_start) == UNWIND_SECOND_LEVEL_REGULAR)
{
struct unwind_info_regular_second_level_page_header header;
memcpy (&header, index_start, sizeof (struct unwind_info_regular_second_level_page_header));
printf (" UNWIND_SECOND_LEVEL_REGULAR #%d entryPageOffset %d, entryCount %d\n", second_level_index_count, header.entryPageOffset, header.entryCount);
printf (" UNWIND_SECOND_LEVEL_REGULAR #%d entryPageOffset %d, entryCount %d\n", baton.current_index_table_number, header.entryPageOffset, header.entryCount);
baton.regular_second_level_page_header = header;
print_second_level_index_regular (baton);
}
Expand All @@ -580,7 +838,7 @@ print_second_level_index (struct baton baton, uint32_t second_level_index_count)
{
struct unwind_info_compressed_second_level_page_header header;
memcpy (&header, index_start, sizeof (struct unwind_info_compressed_second_level_page_header));
printf (" UNWIND_SECOND_LEVEL_COMPRESSED #%d entryPageOffset %d, entryCount %d, encodingsPageOffset %d, encodingsCount %d\n", second_level_index_count, header.entryPageOffset, header.entryCount, header.encodingsPageOffset, header.encodingsCount);
printf (" UNWIND_SECOND_LEVEL_COMPRESSED #%d entryPageOffset %d, entryCount %d, encodingsPageOffset %d, encodingsCount %d\n", baton.current_index_table_number, header.entryPageOffset, header.entryCount, header.encodingsPageOffset, header.encodingsCount);
baton.compressed_second_level_page_header = header;
print_second_level_index_compressed (baton);
}
Expand All @@ -598,6 +856,7 @@ print_index_sections (struct baton baton)
uint8_t *offset = index_section_offset;
while (cur_idx < index_count)
{
baton.current_index_table_number = cur_idx;
struct unwind_info_section_header_index_entry index_entry;
memcpy (&index_entry, offset, sizeof (struct unwind_info_section_header_index_entry));
printf ("index section #%d: functionOffset %d, secondLevelPagesSectionOffset %d, lsdaIndexArraySectionOffset %d\n", cur_idx, index_entry.functionOffset, index_entry.secondLevelPagesSectionOffset, index_entry.lsdaIndexArraySectionOffset);
Expand All @@ -617,19 +876,21 @@ print_index_sections (struct baton baton)
{
struct unwind_info_section_header_lsda_index_entry lsda_entry;
memcpy (&lsda_entry, lsda_entry_offset, sizeof (struct unwind_info_section_header_lsda_index_entry));
uint64_t function_file_address = baton.first_level_index_entry.functionOffset + lsda_entry.functionOffset + baton.text_segment_vmaddr;
uint64_t lsda_file_address = lsda_entry.lsdaOffset + baton.text_segment_vmaddr;
printf (" LSDA [%d] functionOffset %d (%d) (file address 0x%" PRIx64 "), lsdaOffset %d (file address 0x%" PRIx64 ")\n",
lsda_count, lsda_entry.functionOffset,
lsda_entry.functionOffset - index_entry.functionOffset,
lsda_entry.functionOffset - index_entry.functionOffset + baton.text_section_vmaddr,
lsda_entry.lsdaOffset, lsda_entry.lsdaOffset + baton.text_section_vmaddr);
function_file_address,
lsda_entry.lsdaOffset, lsda_file_address);
lsda_count++;
lsda_entry_offset += sizeof (struct unwind_info_section_header_lsda_index_entry);
}

printf ("\n");

baton.first_level_index_entry = index_entry;
print_second_level_index (baton, cur_idx);
print_second_level_index (baton);
}

printf ("\n");
Expand Down Expand Up @@ -662,6 +923,11 @@ int main (int argc, char **argv)

struct baton baton;
baton.mach_header_start = file_mem;
baton.symbols = NULL;
baton.symbols_count = 0;
baton.function_start_addresses = NULL;
baton.function_start_addresses_count = 0;

scan_macho_load_commands (&baton);

if (baton.compact_unwind_start == NULL)
Expand Down Expand Up @@ -699,7 +965,7 @@ int main (int argc, char **argv)
while (pers_idx < header.personalityArrayCount)
{
int32_t pers_delta = *((int32_t*) (baton.compact_unwind_start + header.personalityArraySectionOffset + (pers_idx * sizeof (uint32_t))));
printf (" Personality [%d]: offset to personality function address ptr %d (file address 0x%" PRIx64 ")\n", pers_idx, pers_delta, baton.text_section_vmaddr + pers_delta);
printf (" Personality [%d]: personality function ptr @ offset %d (file address 0x%" PRIx64 ")\n", pers_idx, pers_delta, baton.text_segment_vmaddr + pers_delta);
pers_idx++;
pers_arr += sizeof (uint32_t);
}
Expand Down