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Removing DwarfFDECache at all when _LIBUNWIND_NO_HEAP=1. #1

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Merged
laplab merged 1 commit into from
Nov 19, 2019
Merged

Removing DwarfFDECache at all when _LIBUNWIND_NO_HEAP=1. #1

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19 changes: 17 additions & 2 deletions src/UnwindCursor.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,11 @@ namespace libunwind {

#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
/// Cache of recently found FDEs.

// if we can't use heap = we can't cache anything.
// no need for buffers / rwmutex / class itself
#if !defined(_LIBUNWIND_NO_HEAP)

template <typename A>
class _LIBUNWIND_HIDDEN DwarfFDECache {
typedef typename A::pint_t pint_t;
Expand Down Expand Up @@ -152,7 +157,6 @@ typename A::pint_t DwarfFDECache<A>::findFDE(pint_t mh, pint_t pc) {
template <typename A>
void DwarfFDECache<A>::add(pint_t mh, pint_t ip_start, pint_t ip_end,
pint_t fde) {
#if !defined(_LIBUNWIND_NO_HEAP)
_LIBUNWIND_LOG_IF_FALSE(_lock.lock());
if (_bufferUsed >= _bufferEnd) {
size_t oldSize = (size_t)(_bufferEnd - _buffer);
Expand All @@ -178,7 +182,6 @@ void DwarfFDECache<A>::add(pint_t mh, pint_t ip_start, pint_t ip_end,
}
#endif
_LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
#endif
}

template <typename A>
Expand Down Expand Up @@ -212,6 +215,7 @@ void DwarfFDECache<A>::iterateCacheEntries(void (*func)(
}
_LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
}
#endif // !defined(_LIBUNWIND_NO_HEAP)
#endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)


Expand Down Expand Up @@ -1469,8 +1473,12 @@ bool UnwindCursor<A, R>::getInfoFromDwarfSection(pint_t pc,
}
#endif
if (!foundFDE) {
#if !defined(_LIBUNWIND_NO_HEAP)
// otherwise, search cache of previously found FDEs.
pint_t cachedFDE = DwarfFDECache<A>::findFDE(sects.dso_base, pc);
#else
pint_t cachedFDE = 0;
#endif
if (cachedFDE != 0) {
foundFDE =
CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
Expand Down Expand Up @@ -1503,13 +1511,16 @@ bool UnwindCursor<A, R>::getInfoFromDwarfSection(pint_t pc,

// Add to cache (to make next lookup faster) if we had no hint
// and there was no index.
#if !defined(_LIBUNWIND_NO_HEAP)
if (!foundInCache && (fdeSectionOffsetHint == 0)) {
#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
if (sects.dwarf_index_section == 0)
#endif
DwarfFDECache<A>::add(sects.dso_base, fdeInfo.pcStart, fdeInfo.pcEnd,
fdeInfo.fdeStart);
}
#endif // !defined(_LIBUNWIND_NO_HEAP)

return true;
}
}
Expand Down Expand Up @@ -1894,7 +1905,11 @@ void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
// There is no static unwind info for this pc. Look to see if an FDE was
// dynamically registered for it.
#if !defined(_LIBUNWIND_NO_HEAP)
pint_t cachedFDE = DwarfFDECache<A>::findFDE(0, pc);
#else
pint_t cachedFDE = 0;
#endif
if (cachedFDE != 0) {
CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
Expand Down
6 changes: 6 additions & 0 deletions src/libunwind.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -246,7 +246,9 @@ _LIBUNWIND_HIDDEN void __unw_iterate_dwarf_unwind_cache(void (*func)(
unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
_LIBUNWIND_TRACE_API("__unw_iterate_dwarf_unwind_cache(func=%p)",
reinterpret_cast<void *>(func));
#if !defined(_LIBUNWIND_NO_HEAP)
DwarfFDECache<LocalAddressSpace>::iterateCacheEntries(func);
#endif
}
_LIBUNWIND_WEAK_ALIAS(__unw_iterate_dwarf_unwind_cache,
unw_iterate_dwarf_unwind_cache)
Expand All @@ -261,10 +263,12 @@ void __unw_add_dynamic_fde(unw_word_t fde) {
if (message == NULL) {
// dynamically registered FDEs don't have a mach_header group they are in.
// Use fde as mh_group
#if !defined(_LIBUNWIND_NO_HEAP)
unw_word_t mh_group = fdeInfo.fdeStart;
DwarfFDECache<LocalAddressSpace>::add((LocalAddressSpace::pint_t)mh_group,
fdeInfo.pcStart, fdeInfo.pcEnd,
fdeInfo.fdeStart);
#endif
} else {
_LIBUNWIND_DEBUG_LOG("__unw_add_dynamic_fde: bad fde: %s", message);
}
Expand All @@ -273,7 +277,9 @@ void __unw_add_dynamic_fde(unw_word_t fde) {
/// IPI: for __deregister_frame()
void __unw_remove_dynamic_fde(unw_word_t fde) {
// fde is own mh_group
#if !defined(_LIBUNWIND_NO_HEAP)
DwarfFDECache<LocalAddressSpace>::removeAllIn((LocalAddressSpace::pint_t)fde);
#endif // !defined(_LIBUNWIND_NO_HEAP)
}
#endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
#endif // !defined(__USING_SJLJ_EXCEPTIONS__)
Expand Down