symbol files defaults (PDB on MSVC) and install

From: mbartosik (mbartosik_at_[hidden])
Date: 2004-12-11 03:41:19

With MSVC (and Intel on Windows), .PDB files are essential to 
debugging. This is not just for debug builds but for release builds 
too.

With the boost build system a PDB file will be generated when:

<debug-symbols>on
<debug-store>database

Without a .PDB the generated images cannot be debugged either for a 
live process or a .DMP file (like a unix core file). Microsoft has 
wisely with VS7 (Visual Studio 7 / .NET) and above made generation 
of .PDB files the default for both release and debug builds (it was 
not default for VS6). 

If <debug-store> is set to 'object' then the debugging information is 
built into the library files (static and dynamic link). This bloats 
dynamic link libraries, and is thus not the preferred mechanism for 
dynamic link libraries, but is still very good for static link.

It is my firm belief that software (inc boost) when built with MSVC 
(or Intel on Windows) should always generate debugging information. 
Since the .PDB is a separate file it does not bloat the generated 
executable image and is not typically shipped. An experienced 
developer is likely to turn debug symbols on, but the defaults should 
cater for the inexperienced too. It is not practical to generate 
a .PDB only after a crash because the MS linker uses GUIDs in the 
image and the .PDB.

The default place to install a .PDB file is the libdir (see 
C:\Program Files\Microsoft Visual Studio .NET\Vc7\lib). With 
Microsoft they place .PDB files for static links into the libdir and 
allow you to download the .PDB files for dynamic links from their 
symbols server.

I would like to propose that the boost build for at least MSVC and 
Intel on Windows do the following:

variant release
<debug-symbols>on
# <debug-store> database for dynamic link - research pending for 
static link

I don't know enough about the downsides on platforms other than 
Microsoft (e.g. executable image bloat due to a .debug section), but 
<debug-symbols>on might be suitable for variant common.

IMPORTANTLY
===========
For the install and stage rules.
For static link the generated .PDB files should be installed to 
libdir.
For dynamic link the generated .PDB files should be installed to 
bindir.
The install and staging should be conditional on <debug-symbols>on 
<debug-store>database.

Changing the install and stage rules I expect to be more difficult 
and thus more important as it is easy to set <debug-symbols>on.

Andreas Huber raised a similar point (on Nov 9 2004) 
http://groups.yahoo.com/group/jamboost/message/7893
and Vladimir Prus gave a good reply but my proposal is to change the 
default way the boost builds with MSVC (which is different to what 
Andreas asked).

I am hoping that one of the build experts will reply, and agree to 
update the build rules. If the experts agree I'll research the issues 
between using /Zi and /Z7 for static link libraries so that boost can 
default to the best (if there is one).

Thanks