How can we detect or specify which section of the code consumes a lot of time?

Is there a tool which can specify the section of the code that consumes a lot of time. Assumes our code is divided into basic blocks. I need to specify accurately the basic block that consumes a lot of time than others to execute. I performed it by using some Linux-macros. i.e by inserting additional code at top and end of each basic block. But this approach seems to be ugly.

any help?

with regards