Hello, >From DWARF standard I read that basic block info can also be stored in DWARF line number tables so that a DWARF consumer can match basic blocks with the machine code addresses. And I found in gcc 3.x there is an option "-a" to support output basic block information. However, in gcc 4.x this option is no longer available and I cannot find any basic lock info in line number tables through dwarfdump. Do gcc still record this information? What command line option is needed to enable this? Thanks, Yue Liu