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Retrieve the dyld shared cache mapping offset from the shared cache instead of hardcoding the value. 

Read the version number of the dyld shared cache.
<rdar://problem/13311882> 

llvm-svn: 176589
This commit is contained in:
Jason Molenda 2013-03-06 23:17:36 +00:00
parent a03a85a425
commit 255f9bbcf4
1 changed files with 64 additions and 14 deletions
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78
lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
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@ -1531,11 +1531,11 @@ ObjectFileMachO::ParseSymtab (bool minimize)
FileSpec dsc_filespec(dsc_path, false);
// We need definitions of two structures in the on-disk DSC, copy them here manually
struct lldb_copy_dyld_cache_header
struct lldb_copy_dyld_cache_header_v0
{
char magic[16];
uint32_t mappingOffset;
uint32_t mappingCount;
char magic[16]; // e.g. "dyld_v0 i386", "dyld_v1 armv7", etc.
uint32_t mappingOffset; // file offset to first dyld_cache_mapping_info
uint32_t mappingCount; // number of dyld_cache_mapping_info entries
uint32_t imagesOffset;
uint32_t imagesCount;
uint64_t dyldBaseAddress;
@ -1543,9 +1543,35 @@ ObjectFileMachO::ParseSymtab (bool minimize)
uint64_t codeSignatureSize;
uint64_t slideInfoOffset;
uint64_t slideInfoSize;
uint64_t localSymbolsOffset; // file offset of where local symbols are stored
uint64_t localSymbolsSize; // size of local symbols information
};
struct lldb_copy_dyld_cache_header_v1
{
char magic[16]; // e.g. "dyld_v0 i386", "dyld_v1 armv7", etc.
uint32_t mappingOffset; // file offset to first dyld_cache_mapping_info
uint32_t mappingCount; // number of dyld_cache_mapping_info entries
uint32_t imagesOffset;
uint32_t imagesCount;
uint64_t dyldBaseAddress;
uint64_t codeSignatureOffset;
uint64_t codeSignatureSize;
uint64_t slideInfoOffset;
uint64_t slideInfoSize;
uint64_t localSymbolsOffset;
uint64_t localSymbolsSize;
uint8_t uuid[16]; // v1 and above, also recorded in dyld_all_image_infos v13 and later
};
struct lldb_copy_dyld_cache_mapping_info
{
uint64_t address;
uint64_t size;
uint64_t fileOffset;
uint32_t maxProt;
uint32_t initProt;
};
struct lldb_copy_dyld_cache_local_symbols_info
{
uint32_t nlistOffset;
@ -1578,19 +1604,48 @@ ObjectFileMachO::ParseSymtab (bool minimize)
//
// Save some VM space, do not map the entire cache in one shot.
if (DataBufferSP dsc_data_sp = dsc_filespec.MemoryMapFileContents(0, sizeof(struct lldb_copy_dyld_cache_header)))
DataBufferSP dsc_data_sp;
dsc_data_sp = dsc_filespec.MemoryMapFileContents(0, sizeof(struct lldb_copy_dyld_cache_header_v1));
if (dsc_data_sp)
{
DataExtractor dsc_header_data(dsc_data_sp, byte_order, addr_byte_size);
lldb::offset_t offset = offsetof (struct lldb_copy_dyld_cache_header, mappingOffset);
char version_str[17];
int version = -1;
lldb::offset_t offset = 0;
memcpy (version_str, dsc_header_data.GetData (&offset, 16), 16);
version_str[16] = '\0';
if (strncmp (version_str, "dyld_v", 6) == 0 && isdigit (version_str[6]))
{
int v;
if (::sscanf (version_str + 6, "%d", &v) == 1)
{
version = v;
}
}
offset = offsetof (struct lldb_copy_dyld_cache_header_v1, mappingOffset);
uint32_t mappingOffset = dsc_header_data.GetU32(&offset);
// If the mappingOffset points to a location inside the header, we've
// opened an old dyld shared cache, and should not proceed further.
if (mappingOffset >= sizeof(struct lldb_copy_dyld_cache_header))
if ((version == 0 && mappingOffset >= sizeof(struct lldb_copy_dyld_cache_header_v0))
|| (version >= 1 && mappingOffset >= sizeof(struct lldb_copy_dyld_cache_header_v1)))
{
offset = offsetof (struct lldb_copy_dyld_cache_header, localSymbolsOffset);
DataBufferSP dsc_mapping_info_data_sp = dsc_filespec.MemoryMapFileContents(mappingOffset, sizeof (struct lldb_copy_dyld_cache_mapping_info));
DataExtractor dsc_mapping_info_data(dsc_mapping_info_data_sp, byte_order, addr_byte_size);
offset = 0;
// The File addresses (from the in-memory Mach-O load commands) for the shared libraries
// in the shared library cache need to be adjusted by an offset to match up with the
// dylibOffset identifying field in the dyld_cache_local_symbol_entry's. This offset is
// recorded in mapping_offset_value.
const uint64_t mapping_offset_value = dsc_mapping_info_data.GetU64(&offset);
offset = offsetof (struct lldb_copy_dyld_cache_header_v1, localSymbolsOffset);
uint64_t localSymbolsOffset = dsc_header_data.GetU64(&offset);
uint64_t localSymbolsSize = dsc_header_data.GetU64(&offset);
@ -1607,14 +1662,9 @@ ObjectFileMachO::ParseSymtab (bool minimize)
struct lldb_copy_dyld_cache_local_symbols_info local_symbols_info;
dsc_local_symbols_data.GetU32(&offset, &local_symbols_info.nlistOffset, 6);
// The local_symbols_infos offsets are offsets into local symbols memory, NOT file offsets!
// We first need to identify the local "entry" that matches the current header.
// The "entry" is stored as a file offset in the dyld_shared_cache, so we need to
// adjust the raw m_header value by slide and 0x30000000.
SectionSP text_section_sp(section_list->FindSectionByName(GetSegmentNameTEXT()));
uint32_t header_file_offset = (text_section_sp->GetFileAddress() - 0x30000000);
uint32_t header_file_offset = (text_section_sp->GetFileAddress() - mapping_offset_value);
offset = local_symbols_info.entriesOffset;
for (uint32_t entry_index = 0; entry_index < local_symbols_info.entriesCount; entry_index++)