================
@@ -1787,20 +1787,37 @@ bool UnwindCursor<A, R>::getInfoFromDwarfSection(
}
if (!foundFDE) {
// Still not found, do full scan of __eh_frame section.
- foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
- sects.dwarf_section_length, 0,
- &fdeInfo, &cieInfo);
+ // But only if __eh_frame_hdr is absent or empty.
+ // We assume that both sections have the same data, and don't want to waste
+ // time for long scan for absent addresses.
+ bool hasEHHeaderData = false;
+#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
+ if ((sects.dwarf_index_section != 0)) {
+ typename EHHeaderParser<A>::EHHeaderInfo hdrInfo;
+ const pint_t ehHdrStart = sects.dwarf_index_section;
+ const pint_t ehHdrEnd = ehHdrStart + sects.dwarf_index_section_length;
+ if (EHHeaderParser<A>::decodeEHHdr(_addressSpace, ehHdrStart, ehHdrEnd,
+ hdrInfo)) {
+ hasEHHeaderData = (hdrInfo.fde_count != 0);
+ }
+ }
+#endif
+ if (!hasEHHeaderData) {
+ foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
+ sects.dwarf_section_length, 0,
&fdeInfo,
+ &cieInfo);
+ }
}
if (foundFDE) {
if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, sects.dso_base)) {
// Add to cache (to make next lookup faster) if we had no hint
// and there was no index.
if (!foundInCache && (fdeSectionOffsetHint == 0)) {
- #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
+#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
----------------
MaskRay wrote:
Can you drop this unrelated formatting? (ignoring clang-format warning)
https://github.com/llvm/llvm-project/pull/167849
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