Re: preprocessor/2948

[Sean McNeil <sean at mcneil dot com>]

The following reply was made to PR preprocessor/2948; it has been noted by GNATS.

From: Sean McNeil <sean@mcneil.com>
To: Neil Booth <neil@daikokuya.demon.co.uk>
Cc: nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: preprocessor/2948
Date: Mon, 28 May 2001 18:54:22 -0700

 Neil,
 
 This has puzzled me for a while and I've tried several additional things as we've been
 discussing this.  I noticed that the cc1plus program installs handlers for various
 pragmas and discovered a #pragma implementation in PlotFile.cpp.  When I remove this
 pragma, compilation is as I expected.
 
 HOWEVER....  there is no template code that exists within the ttt.ii file (after
 preprocessor) and adding a #pragma implementation to ttt.cc (copy of ttt.ii) doesn't
 reproduce the problem either.  So I am still at a loss as to why
 
 1) there is a #pragma implementation in this file (Something I do not expect anyone on
 the gcc team to answer :).
 2) why code is generated for the pragma even though -fexternal-templates was not
 defined.
 
 I suppose what it boils down to is it's not a cpp problem, but a cc1plus problem.
 Should this be reassigned?
 
 Sean
 
 Neil Booth wrote:
 
 > Hi Sean,
 >
 > The command lines look identical in their effects to me.  I honestly
 > have no idea what is going wrong.  I'll leave your bug report open, of
 > course.
 >
 > If you could narrow it down by removing code and / or command line
 > options until the difference in behaviour vanishes, it would help a
 > lot.  Otherwise this kind of thing, by its very nature, is hard to
 > get a grip on.
 >
 > Neil.
 >
 > Sean McNeil wrote:-
 >
 > > Here is the information you requested.
 >
 > >  I've also tried running the code through with the -E option twice
 > > to see if the cpp is changing the code in any way in the second
 > > pass-through.  The only difference was in some white space and diff
 > > -cb shows no differences.  I was under the impression that the cpp
 > > is now a library invoked directly from the different modules
 > > (C,C++,etc.).  Could it be that the format/switches used between how
 > > the cpp is invoked with the -E option and without it are different?
 > > The -v option indicates that cpp0 is not called so it must now get
 > > used by cc1plus directly.
 > >
 > > [root@blue libstdcxx]# arm-wrs-vxworks-g++ -S -v -mcpu=arm8 -mapcs-32
 > > -mlittle-endian -ansi -nostdinc -fno-implicit-templates -DVXW_EXPLICIT_TEMPLATES
 > > -O2 -mno-sched-prolog -I/usr/wind/target/h -DCPU=ARMARCH4 -DARMEL -fno-exceptions
 > > -o /tmp/ttt-bad.s PlotFile.cpp
 > > Reading specs from
 > > /usr/wind/host/x86-freebsd/lib/gcc-lib/arm-wrs-vxworks/3.1/specs
 > > Configured with: ../configure --prefix=/usr/wind/host/x86-freebsd
 > > --target=arm-wrs-vxworks
 > > Thread model: vxworks
 > > gcc version 3.1 20010525 (experimental)
 > >  /usr/wind/host/x86-freebsd/lib/gcc-lib/arm-wrs-vxworks/3.1/cc1plus -nostdinc -v
 > > -I/usr/wind/target/h -D__GNUC__=3 -D__GNUC_MINOR__=1 -D__GNUC_PATCHLEVEL__=0
 > > -D__vxworks -D__arm__ -D__svr4__ -Acpu=arm -Amachine=arm -D__CHAR_UNSIGNED__
 > > -D__OPTIMIZE__ -D__STDC_HOSTED__=1 -D__ARM_ARCH_4__ -D__APCS_32__ -D__ARMEL__
 > > -D__CPU__=ARMARCH4 -D__arm__ -DVXW_EXPLICIT_TEMPLATES -DCPU=ARMARCH4 -DARMEL
 > > PlotFile.cpp -D__GNUG__=3 -D_GNU_SOURCE -D__DEPRECATED -D__GXX_ABI_VERSION=100
 > > -D__STRICT_ANSI__ -trigraphs -$ -quiet -dumpbase PlotFile.cpp -mcpu=arm8 -mapcs-32
 > > -mlittle-endian -mno-sched-prolog -ansi -O2 -ansi -version -fno-implicit-templates
 > > -fno-exceptions -o /tmp/ttt-bad.s
 > > GNU CPP version 3.1 20010525 (experimental) (cpplib) (ARM/COFF)
 > > GNU C++ version 3.1 20010525 (experimental) (arm-wrs-vxworks)
 > >  compiled by GNU C version 2.95.3 [FreeBSD] 20010315 (release).
 > > #include "..." search starts here:
 > > #include <...> search starts here:
 > >  /usr/wind/target/h
 > > End of search list.
 > >
 > >
 > > [root@blue libstdcxx]# arm-wrs-vxworks-g++ -E -v -mcpu=arm8 -mapcs-32
 > > -mlittle-endian -ansi -nostdinc -fno-implicit-templates -DVXW_EXPLICIT_TEMPLATES
 > > -O2 -mno-sched-prolog -I/usr/wind/target/h -DCPU=ARMARCH4 -DARMEL -fno-exceptions
 > > -o /tmp/ttt.ii PlotFile.cpp
 > > Reading specs from
 > > /usr/wind/host/x86-freebsd/lib/gcc-lib/arm-wrs-vxworks/3.1/specs
 > > Configured with: ../configure --prefix=/usr/wind/host/x86-freebsd
 > > --target=arm-wrs-vxworks
 > > Thread model: vxworks
 > > gcc version 3.1 20010525 (experimental)
 > >  /usr/wind/host/x86-freebsd/lib/gcc-lib/arm-wrs-vxworks/3.1/cpp0 -lang-c++
 > > -D_GNU_SOURCE -D__GNUG__=3 -D__DEPRECATED -D__GXX_ABI_VERSION=100
 > > -D__STRICT_ANSI__ -trigraphs -$ -nostdinc -v -I/usr/wind/target/h -D__GNUC__=3
 > > -D__GNUC_MINOR__=1 -D__GNUC_PATCHLEVEL__=0 -D__vxworks -D__arm__ -D__svr4__
 > > -Acpu=arm -Amachine=arm -D__CHAR_UNSIGNED__ -D__OPTIMIZE__ -D__STDC_HOSTED__=1
 > > -D__ARM_ARCH_4__ -D__APCS_32__ -D__ARMEL__ -D__CPU__=ARMARCH4 -D__arm__
 > > -DVXW_EXPLICIT_TEMPLATES -DCPU=ARMARCH4 -DARMEL PlotFile.cpp -o /tmp/ttt.ii
 > > GNU CPP version 3.1 20010525 (experimental) (cpplib) (ARM/COFF)
 > > #include "..." search starts here:
 > > #include <...> search starts here:
 > >  /usr/wind/target/h
 > > End of search list.
 > >
 > > [root@blue libstdcxx]# arm-wrs-vxworks-g++ -S -v -mcpu=arm8 -mapcs-32
 > > -mlittle-endian -ansi -nostdinc -fno-implicit-templates -DVXW_EXPLICIT_TEMPLATES
 > > -O2 -mno-sched-prolog -I/usr/wind/target/h -DCPU=ARMARCH4 -DARMEL -fno-exceptions
 > > -o /tmp/ttt.s /tmp/ttt.ii
 > > Reading specs from
 > > /usr/wind/host/x86-freebsd/lib/gcc-lib/arm-wrs-vxworks/3.1/specs
 > > Configured with: ../configure --prefix=/usr/wind/host/x86-freebsd
 > > --target=arm-wrs-vxworks
 > > Thread model: vxworks
 > > gcc version 3.1 20010525 (experimental)
 > >  /usr/wind/host/x86-freebsd/lib/gcc-lib/arm-wrs-vxworks/3.1/cc1plus -fpreprocessed
 > > /tmp/ttt.ii -quiet -dumpbase ttt.ii -mcpu=arm8 -mapcs-32 -mlittle-endian
 > > -mno-sched-prolog -ansi -O2 -ansi -version -fno-implicit-templates -fno-exceptions
 > > -o /tmp/ttt.s
 > > GNU CPP version 3.1 20010525 (experimental) (cpplib) (ARM/COFF)
 > > GNU C++ version 3.1 20010525 (experimental) (arm-wrs-vxworks)
 > >  compiled by GNU C version 2.95.3 [FreeBSD] 20010315 (release).