Re: The bugs in make v3.82

[Paul Smith]

On Tue, 2010-09-28 at 13:54 +0400, Alexander Kornilov wrote:
> BUG #0001:
> -----------
> 
> Description: The rule for generation dependency file (%.d) doesn't work
> on Linux platform;
> Severity: Major;
> 
> Steps to reproduce:
> 1. Unpack bug_0001.zip files from letter attachment;
> 2. Execute makefile from archive on Linux platform. Result of operation:
>      > make
>      Creating dir Obj
>      Generate dependency for test1.cpp
>      Generate dependency for test2.cpp

Interesting.  When I tried your test case with GNU make 3.82 it failed
with a different, very subtle bug.

However, your makefile is wrong and that's why it's failing for you in
GNU make 3.81.  I have no idea why it works in Windows; if it does
that's a bug in the Windows version of make, IMO.

You have rules like this:

        %.o: %.cpp makefile
                @echo Compiling $<;
                @echo $@ >$(objDir)$(slash)$@

This goes against one of the fundamental rules of writing makefiles:
your recipe MUST update the target that make wants it to.  The target
make wants it to update is the file address@hidden  Your recipe is not creating 
$@,
it's creating $(objDir)$(slash)$@, which is an entirely different file.

Basically, your approach is not going to work.  You are trying to use
vpath to find _OBJECT_ files, but when make runs the object files don't
yet exist so make can't find them.  You can't use vpath for this; vpath
is only for finding _SOURCE_ files: files that always exist, not files
that make builds.

I think you should read the following; they bear directly on your
situation:

http://make.mad-scientist.us/rules.html
http://make.mad-scientist.us/vpath.html
http://make.mad-scientist.us/autodep.html

> Klocwork:
> ----------
> 
> In file klocwork_report_make_v3.82.zip I attach static code analysis
> tool Klocwork report for make v3.82 generated by my build system.
> Klocwork find many vulnerabilities and warnings in make code. According
> my experience Klocwork is 'smart' tool  and maybe you find it's comments
> useful for make improvement.

I'll take a look but often these tools show many false positives.

> Make language:
> ---------------
> In my build system I am often use condition constructions and upset by
> make language restrictions  Are you plan support condition construction
> like this:
> ifeq ($(SHELL), sh.exe) && (($(target_platform), WinXP) ||
> ($(target_platform), WinVista))
> endif
> 
> ifeq ($(SHELL), sh.exe)
>   <..>
> elif ($(SHELL), /bin/bash)
>   <..>
> endif
> 
> I mind AND (&& and OR (||) 'elif' operations in ifeq.

In GNU make 3.82 you can write "ifeq else ifeq endif"-style constructs.

There are also $(and ...) and $(or ...) functions available in both 3.81
and 3.82.  However, they don't work quite as you describe above.

Please check the manual for full details.

> Questions:
> -----------
> 
> I doesn't find solve of this my problem in user-guide. Could I 'know'
> what particular target user pass to make?
> e.g. > make clean

Look up the MAKECMDGOALS variable in the manual.

-- 
-------------------------------------------------------------------------------
 Paul D. Smith <address@hidden>          Find some GNU make tips at:
 http://www.gnu.org                      http://make.mad-scientist.net
 "Please remain calm...I may be mad, but I am a professional." --Mad Scientist