Martin Kirchengast <martin_kir_@xxxxxxxxxxx> writes: > what is the data format of "initial_location" and "address_range" in > the .eh_frame section of an ELF64 binary? I read the DWARF > specification which says: > > "initial_location (target address): An addressing-unit sized constant indicating the address of the first location associated with this table entry." > > and > > "address_range (target address): An addressing unit sized constant indicating the number of bytes of program instructions described by this entry." > > Because I'm building for x86-64 I thought that must be 64 bit, but > that seems to be wrong. Yes. It's a 32-bit value for most targets. Note that the value is normally PC relative--it's the offset from the FDE to the address which it covers. So 32 bits is normally sufficient. The number of bytes is also normally 32 bits. > 00000020 0000001c 00000024 FDE cie=00000000 pc=000000ec..000000f6 > Contents of section .eh_frame: > 3b78 1c000000 00000000 017a5052 00017810 .........zPR..x. > 3b88 0a005423 00000000 00001b0c 07089001 ..T#............ > 3b98 1c000000 24000000 4cc5ffff 0a000000 ....$...L....... > 3ba8 00410e10 4386020d 06450c07 08000000 .A..C....E...... > > According to the above output of readelf the value of address_range > should be 0xf6 - 0xec = 0xa. This value is at address 0x3ba4 and seems > to be 32 bit wide. initial_location hast to be at address 0x3ba0, is > 32 bit wide too and has a quite weird value. So please tell what am I > doing wrong here? The initial_location value is at 0x3ba0 is 0xffffc54c. 0x3ba0 + 0xffffc54c == 0xec, which is the value you want. Ian
