GNU: do not read the FDE count if omitted

compnerd · compnerd · commit f7596ece7657 · 2017-10-20T18:47:35.000Z
If there is no binary search table computed, the FDECount encoding is
DW_EH_PE_omit.  Do not attempt to read the FDECount in such a situation
as we will read an incorrect value.  binutils only writes out the
FDECount if the encoding is not DW_EH_PE_omit.

llvm-svn: 316224
diff --git a/libunwind/src/EHHeaderParser.hpp b/libunwind/src/EHHeaderParser.hpp
@@ -67,7 +67,9 @@ void EHHeaderParser<A>::decodeEHHdr(A &addressSpace, pint_t ehHdrStart,
   ehHdrInfo.eh_frame_ptr =
       addressSpace.getEncodedP(p, ehHdrEnd, eh_frame_ptr_enc, ehHdrStart);
   ehHdrInfo.fde_count =
-      addressSpace.getEncodedP(p, ehHdrEnd, fde_count_enc, ehHdrStart);
+      fde_count_enc == DW_EH_PE_omit
+          ? 0
+          : addressSpace.getEncodedP(p, ehHdrEnd, fde_count_enc, ehHdrStart);
   ehHdrInfo.table = p;
 }
 
