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delete a.cpp

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nora 2023-06-13 14:35:18 +02:00
parent 18d980357d
commit 4baab43e17
1 changed files with 0 additions and 61 deletions
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a.cpp
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@ -1,61 +0,0 @@
bool findUnwindSections(int_t targetAddr, UnwindInfoSections &info)
{
// Use DLFO_STRUCT_HAS_EH_DBASE to determine the existence of
// `_dl_find_object`. Use _LIBUNWIND_SUPPORT_DWARF_INDEX, because libunwind
// support for _dl_find_object on other unwind formats is not implemented,
// yet.
#if defined(DLFO_STRUCT_HAS_EH_DBASE) & defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
// We expect `_dl_find_object` to return PT_GNU_EH_FRAME.
#if DLFO_EH_SEGMENT_TYPE != PT_GNU_EH_FRAME
#error _dl_find_object retrieves an unexpected section type
#endif
// We look-up `dl_find_object` dynamically at runtime to ensure backwards
// compatibility with earlier version of glibc not yet providing it. On older
// systems, we gracefully fallback to `dl_iterate_phdr`. Cache the pointer
// so we only look it up once. Do manual lock to avoid _cxa_guard_acquire.
static decltype(_dl_find_object) *dlFindObject;
static bool dlFindObjectChecked = false;
if (!dlFindObjectChecked)
{
dlFindObject = reinterpret_cast<decltype(_dl_find_object) *>(
dlsym(RTLD_DEFAULT, "_dl_find_object"));
dlFindObjectChecked = true;
}
// Try to find the unwind info using `dl_find_object`
dl_find_object findResult;
if (dlFindObject && dlFindObject((void *)targetAddr, &findResult) == 0)
{
if (findResult.dlfo_eh_frame == nullptr)
{
// Found an entry for `targetAddr`, but there is no unwind info.
return false;
}
info.dso_base = reinterpret_cast<uintptr_t>(findResult.dlfo_map_start);
info.text_segment_length = static_cast<size_t>(
(char *)findResult.dlfo_map_end - (char *)findResult.dlfo_map_start);
// Record the start of PT_GNU_EH_FRAME.
info.dwarf_index_section =
reinterpret_cast<uintptr_t>(findResult.dlfo_eh_frame);
// `_dl_find_object` does not give us the size of PT_GNU_EH_FRAME.
// Setting length to `SIZE_MAX` effectively disables all range checks.
info.dwarf_index_section_length = SIZE_MAX;
EHHeaderParser<LocalAddressSpace>::EHHeaderInfo hdrInfo;
if (!EHHeaderParser<LocalAddressSpace>::decodeEHHdr(
*this, info.dwarf_index_section, info.dwarf_index_section_length,
hdrInfo))
{
return false;
}
// Record the start of the FDE and use SIZE_MAX to indicate that we do
// not know the end address.
info.dwarf_section = hdrInfo.eh_frame_ptr;
info.dwarf_section_length = SIZE_MAX;
return true;
}
#endif
dl_iterate_cb_data cb_data = {this, &info, targetAddr};
int found = dl_iterate_phdr(findUnwindSectionsByPhdr, &cb_data);
return static_cast<bool>(found);
}