[libunwind] Fix CIE v1 return address parsing
- For CIE version 1 (e.g. in DWARF 2.0.0), the return_address_register
field is a ubyte [0..255].
- For CIE version 3 (e.g. in DWARF 3), the field is instead a ULEB128
constant.
Previously, libunwind accepted a CIE version of 1 or 3, but always
parsed the field as ULEB128.
Clang always outputs CIE version 1 into .eh_frame. (It can output CIE
version 3 or 4, but only into .debug_frame.)
Differential Revision: https://reviews.llvm.org/D83741
GitOrigin-RevId: 52d0a78b831584c46eda78b7cf349ab93ce13df0
diff --git a/src/DwarfParser.hpp b/src/DwarfParser.hpp
index d05ac46..c98c4f9 100644
--- a/src/DwarfParser.hpp
+++ b/src/DwarfParser.hpp
@@ -336,7 +336,8 @@
// parse data alignment factor
cieInfo->dataAlignFactor = (int)addressSpace.getSLEB128(p, cieContentEnd);
// parse return address register
- uint64_t raReg = addressSpace.getULEB128(p, cieContentEnd);
+ uint64_t raReg = (version == 1) ? addressSpace.get8(p++)
+ : addressSpace.getULEB128(p, cieContentEnd);
assert(raReg < 255 && "return address register too large");
cieInfo->returnAddressRegister = (uint8_t)raReg;
// parse augmentation data based on augmentation string
