Re: "File has no CTF section."
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Em Tue, Mar 25, 2008 at 10:24:03AM -0500, Florin Iucha escreveu: > I have manually built the pahole&co on Ubuntu 8.04 beta, and I'm > trying to use it on a few source files that I have, and I keep getting > the "File has no CTF section." error message. Argh, I have to fix that, this just means that the file doesn't have DWARF info _nor_ CTF info. > I have three object files: one is 'dwarves.o' from the pahole > distribution, compiled with 'gcc -g'. Another is 'foobar.o' from my > own embedded application, compiled with the same compiler, on the same > box . The third object file is 'foobar.o' compiled with some > version of compiler (Metrowerks?) for the embedded platform that we use. > > If I use 'objdump -W' on all three files, I get heaps of information, > including the structure definitions and other stuff. Good. can you try with: # binutils readelf -w i build/pahole # elfutils eu-readelf -w i build/pahole > If I use 'pahole' on all three files, I get the structure information > for the first one, but 'File has no CTF section.' for the other two, > even though the first and second object files are built with the same > compiler! And even though both 'foobar.o' file contain heaps of > debugging information (objdump -W yields 14K lines for the gcc-4.2 > build and 43K lines for the native embedded build). > > I grepped for 'File has no CTF section.' in the dwarves sources and it > only occurs in the 'ctf_loader.c' file - it seems that the code is > looking for a section named ".SUNW_ctf" (in function parse_elf which > is only called from ctf__load which is only called from cus__loadfl, > if the dwarf__load returns some empty list) > > It seems that either 'dwfl_getdwarf/dwarf_nextcu' fails to find the > data. At any rate, the error message (about the missing CTF section) > is quite misleading. I'm not sure where the bug is (although my > limited exploring seems to point to the 'elfutils' package. Ubuntu > distributes version 0.131, which seems to be the latest published version. indeed, misleading it is, fixing now... done > The most puzzling thing is that two object files, compiled with the > same compiler on the same machine have different enough DWARF data > that one works with pahole and one doesn't. > > What can I do to follow through with this? Contact the elfutils > maintainers? Possibly, but can you make these two object files available somewhere? I'd like to take a look... > Thanks, > florin > > 1: The compiler version is 'gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu6)' > > -- > Bruce Schneier expects the Spanish Inquisition. > http://geekz.co.uk/schneierfacts/fact/163 -- To unsubscribe from this list: send the line "unsubscribe dwarves" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html