[Click] line numbers in click binary symbol table

[Ian Rose]

Roman -

Doh!  The -g option was the trick - I included it in CFLAGS but not 
CXXFLAGS. :(

Thanks much,
Ian


Roman Chertov wrote:
> Ian,
> 
> When you are compiling for debugging, do not use the O2 flag is it makes
> it hard to match the program with the code (gcc can move instructions
> about).  An easy way to see if you have debugging symbols in the code is
> to place a break point in your code.  If you can't see your code at the
> break point, you don't have debugging symbols (you will probably have
> problems placing the break point in the first place).
> 
> Make sure that the -g option is passed to the compiler and the linker.
> Also, rebuild the whole project to ensure that you get debugging
> information built in. I've done this in past with click, but it takes a
> bit of mucking around with the make file.
> 
> Roman
> 
> Ian Rose wrote:
>> Hi list,
>>
>> This may or may not be specific to Click, so apologies in advance if I 
>> am off topic.  I am attempting to do some debugging of my (userlevel) 
>> click app and I am finding that the symbol table of the resulting click 
>> binary has very few line numbers in it (as viewed by 'nm -l -C 
>> bin/click').  This is a problem for me because it means that basically 
>> every address that I pass to addr2line returns '??:0' for the file and 
>> line number.  I've also had some problems getting useful information out 
>> of coredumps (which is why I am messing about with addr2line instead of 
>> just gdb), perhaps for the same reason?
>>
>> My knowledge is rather limited as far as compiling and linking go, so my 
>> question is whether this is somehow Click's doing (perhaps its stripping 
>> most of the line numbers?) or whether this is normal gcc/ld behavior 
>> that I'm just unfamiliar with.  Other than click, I pretty much 
>> exclusively use C over C++ so if there is some different behavior for 
>> C++ code I wouldn't know it.  I've tried digging through the click 
>> Makefiles but I haven't found anything incriminating.  Also, I've 
>> confirmed that I am compiling with -g and I have tried both with and 
>> without -O2 with no noticeable difference.
>>
>> Many thanks for any tips!
>> - Ian
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