How to have gcc generate assembler code with C source listed?

Bob Plantz wrote:
Fri, 2008-07-04 at 10:55 +0100, Andrew Haley wrote:
>Chen (™ˆ) Jun (†›) wrote:
Is there any options to enable this? If yes, since what version of gcc
is it supported?
>All of them.
>>
>-g -Wa,-adhls

Very nice. I didn't know about this.

Can you tell me where .loc is documented?
When I see something like:
.loc 1 15 0
in the assembly language, I easily figured out that 15 is the line
number in the original C code. But it would be nice to know what the
other two numbers mean.

I have no idea; if I wanted to know I'd look in the gcc source to see what
this generates.

Andrew.