Suppress -fprofile-arcs in extras.o rule

Suppress -fprofile-arcs in extras.o rule

[John Dallaway]

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This patch eliminates the possibility of passing -fprofile-arcs from the
global CFLAGS to the linker when generating extras.o. -fprofile-arcs
would imply -lgcov and interfere with subsequent application linking.

Checked-in.

John Dallaway

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Index: ChangeLog
===================================================================
RCS file: /cvs/ecos/ecos/packages/hal/common/current/ChangeLog,v
retrieving revision 1.120
diff -U5 -r1.120 ChangeLog
--- ChangeLog	9 Oct 2010 12:53:34 -0000	1.120
+++ ChangeLog	20 Nov 2010 20:06:40 -0000
@@ -1,5 +1,10 @@
+2010-11-20  John Dallaway  <john@dallaway.org.uk>
+
+	* cdl/hal.cdl: Suppress -fprofile-arcs (which implies -lgcov) when
+	generating extras.o.
+
 2010-10-09  John Dallaway  <john@dallaway.org.uk>
 
 	* doc/porting.sgml: Delete references to the memory layout editor.
 
 2009-02-02  Bart Veer  <bartv@ecoscentric.com>
Index: cdl/hal.cdl
===================================================================
RCS file: /cvs/ecos/ecos/packages/hal/common/current/cdl/hal.cdl,v
retrieving revision 1.25
diff -U5 -r1.25 hal.cdl
--- cdl/hal.cdl	2 Feb 2009 13:46:07 -0000	1.25
+++ cdl/hal.cdl	20 Nov 2010 20:06:40 -0000
@@ -6,11 +6,11 @@
 #
 # ====================================================================
 ## ####ECOSGPLCOPYRIGHTBEGIN####                                            
 ## -------------------------------------------                              
 ## This file is part of eCos, the Embedded Configurable Operating System.   
-## Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+## Copyright (C) 1998, 1999, 2000, 2001, 2002, 2010 Free Software Foundation, Inc.
 ##
 ## eCos is free software; you can redistribute it and/or modify it under    
 ## the terms of the GNU General Public License as published by the Free     
 ## Software Foundation; either version 2 or (at your option) any later      
 ## version.                                                                 
@@ -67,11 +67,11 @@
 
     requires      CYGPKG_INFRA
 
     make -priority 250 {
         <PREFIX>/lib/extras.o: <PREFIX>/lib/libextras.a
-        $(CC) $(CFLAGS) -nostdlib -Wl,-r -T /dev/null -Wl,--whole-archive -o $@ $<
+        $(CC) $(CFLAGS) -fno-profile-arcs -nostdlib -Wl,-r -T /dev/null -Wl,--whole-archive -o $@ $<
     }   
 
     cdl_option CYGBLD_GLOBAL_WARNFLAGS {
         display     "Standard compiler warning flags"
         parent      CYGBLD_GLOBAL_OPTIONS

Re: Suppress -fprofile-arcs in extras.o rule

[Bart Veer]

>>>>> "John" == John Dallaway <john@dallaway.org.uk> writes:

    John> This patch eliminates the possibility of passing
    John> -fprofile-arcs from the global CFLAGS to the linker when
    John> generating extras.o. -fprofile-arcs would imply -lgcov and
    John> interfere with subsequent application linking.

    John> Checked-in.

This makes no sense to me. AFAIK gcc -Wl,--whole-archive should only
invoke the linker, not the compiler, and the option -fprofile-arcs
only affects the compiler (a grep through a binutils checkout for
profile-arcs shows no hits). The presence or absence of
-fprofile-arcs/-fno-profile-arcs in this custom build step should have
no effect whatsoever on the build.

If any of eCos is built with -profile-arcs in the global CFLAGS then
the compiler will generate extra code which will have a dependency,
either on a gcov support library or on some other profiling library
interested in run-time behaviour at the arc level. The linker is not
going to eliminate that extra code just because you add
-fno-profile-arcs to the linker command line, so the dependency
remains.

Hence all this patch achieves is to add some unnecessary and confusing
noise to the build process.

Bart

-- 
Bart Veer                                   eCos Configuration Architect
eCosCentric Limited    The eCos experts      http://www.ecoscentric.com/
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