When using gcc version 4.3.2, I see how to generate specs using:
$ /usr/local/gcc-4.3.2/bin/gcc -v
Using built-in specs
Now changing to the same directory as libgcc:
cd /usr/local/gcc-4.3.2/lib/gcc/x86_64-unknown-linux-gnu/4.3.2
/usr/local/gcc-4.3.2/bin/gcc -dumpspecs > specs
I have a populated specs file that I can modify. However, once that is done I still see that:
$ /usr/local/gcc-4.3.2/bin/gcc -v
Using built-in specs
How do I tell gcc to use that specs file by default rather than forcing me to pass a -specs parameter every compile? I would like it to match another system I have where I get the following:
$ /usr/local/gcc-4.3.2/bin/gcc -v
Reading specs from /usr/local/gcc-4.3.2/lib/gcc/i686-pc-linux-gnu/4.3.2/specs</code>
As you can see, the major difference between the two systems is that the existing setup is 32-bit and I am now trying to match that on a 64-bit system. The version of Linux is otherwise the same and I am compiling the same version of gcc. (With both systems gcc 4.3.2 is the second gcc installation, with 4.1.2 being used to compile 4.3.2)
As hinted at by the strace suggestion by Johannes Schaub - litb, it was a problem with where the compiler was looking for the file. As it turns out, the non-working installation had an environment variable set in the .bashrc that was causing the confusion.
The correct location for the specs file is indeed the same directory that libgcc is in. Just be sure you're looking there.
I used this command line:
/usr/bin/set-gcc-default-3.sh i686-pc-mingw32
but you'll probably want:
/usr/bin/set-gcc-default-4.sh i686-pc-linux-gnu
(Note the -4 instead of -3)
This is built using the "alternatives" stuff, please see
/usr/sbin/alternatives.exe --help
And also see pages such as http://linux.about.com/library/cmd/blcmdl8_alternatives.htm
You rebuild gcc with your specs file as part of the build!
A simpler solution is to create an alias:
alias gcc_Gary gcc -specs /<folder With Specs File>/newSpecsFile
Related
I am trying to compile kernel for Cyanogenmod 13. I am getting error
ERROR: modpost: Found 2 section mismatch(es).
To see full details build your kernel with:
'make CONFIG_DEBUG_SECTION_MISMATCH=y'
To build the kernel despite the mismatches, build with:
'make CONFIG_NO_ERROR_ON_MISMATCH=y'
(NOTE: This is not recommended)
I read it here. That i need to compile my kernel using 4.7.
How can i choose the version of toolchain during cyanogenmod build ??
I believe you need to setup gcc version 4.7 and use CC variable to set it as a compiler. E.g. make target CC=/bin/gcc4.7
More information here and here.
Thanks to #nopasara and his valuable comment.
So i did little research further and discovered that the kernel is compatiable with arm-eabi tool chain not arm-linux-androideabi toolchain. So here is the command i used
export PATH=$PATH:~/android/system/prebuilts/gcc/linux-x86/arm/arm-linux-eabi-4.7/bin/ && export ARCH=arm && export SUBARCH=arm && export CROSS_COMPILE=arm-linux-eabi- && make msm8226_defconfig O=~/android/system/out/target/product/E6790/obj/KERNEL_OBJ
and
make O=~/android/system/out/target/product/E6790/obj/KERNEL_OBJ zImage -j4
To do with this Cyanogenmod add following line to your BoardConfig.mk
TARGET_KERNEL_CROSS_COMPILE_PREFIX := arm-eabi-
and either use
export TARGET_LEGACY_GCC_VERSION=4.7
Or edit ~/android/system/build/core/combo/TARGET_linux-arm.mk and set version in
$(combo_2nd_arch_prefix)TARGET_LEGACY_GCC_VERSION := 4.7
All of a sudden I seem to be struggling with compiling c++ programs (specifically TDM64 5.1.0) from the command-line on Windows (specifically 10) when using wildcard based filenames. It works fine when the names are given in full. I've done this countless times before with no problem Edit: But not normally on windows... my memories of this working before must be false. What am I missing?
C:\Users\Duncan Coulter\Code>dir *.cpp
Volume in drive C has no label.
Volume Serial Number is 9EE6-DBBD
Directory of C:\Users\Duncan Coulter\Code
2016/04/04 01:35 PM 7 869 LittleMan.cpp
2016/04/04 01:35 PM 1 912 main.cpp
2 File(s) 9 781 bytes
0 Dir(s) 90 288 394 240 bytes free
C:\Users\Duncan Coulter\Code>g++ *.cpp
g++: error: *.cpp: Invalid argument
C:\Users\Duncan Coulter\Code>g++ main.cpp LittleMan.cpp
Your problem is where you write:
g++ *.cpp
g++ is a linux style program, and expects the shell to expand wildcards for it. The windows command shell doesn't do that - it expects individual programs to expand wildcards for themselves.
The easiest solution is to download cygwin - which does expand wildcards for you. Otherwise the answers to this question may be useful:
https://superuser.com/questions/460598/is-there-any-way-to-get-the-windows-cmd-shell-to-expand-wildcard-paths
I note that TDM is based on the MINGW port of GCC. I've found that different versions of this compiler do in fact treat the wildcard differently. For example, it works perfectly fine for me as of version 3.4.2, compiling in Windows 7:
However, when I upgraded to GCC v.4.9.2, this batch file and others I was using broke (specifically, the *.cpp was not recognized). This was a version of MINGW GCC which came with the Dev-C++ IDE. Because I needed this feature rather badly (specifically, test-compiling large submissions of student code with unspecified random filenames), I actually had to downgrade and revert back to the old version for just this purpose.
Wondering if it is possible to generate interleaved source and assembly from clang?
I am looking for something equivalent to gcc command (as demonstrated at http://www.fclose.com/240/generate-a-mixed-source-and-assembly-listing-using-gcc/)
gcc -Wa,-adhln -g source_code.c > assembly_list.s
I have visited Link: How do you get assembler output from C/C++ source in gcc? but it gets so far as to list the assembly - but no interleaving.
Also Visual Studio does give you pretty nice interleaved assembly output, details here: How to view the assembly behind the code using Visual C++?
Thank you for all the help.
Sarang
There seems to be a bug reported sometimes last year stating exactly this: http://llvm.org/bugs/show_bug.cgi?id=16647
Bug 16647 - No option to produce mixed source + assembly listing?
So since it is still NEW I guess clang does not have this supported yet.
As an alternative, how about compiling your code and then use objdump -S ? The output format is somewhat similar ...
As of August 2016, the bug that #dragosht mentioned still is open. However, there is a workaround offered by the linked bug 17465: clang -no-integrated-as -Xassembler -adhln. It disables the clang-integrated assembler and calls an external assembler, which hopefully supports the listing-generating options.
That works OK in Linux, but it doesn't work in Mac OS X (as of 10.11.6). The problem is that even the external assembler in OS X does not support the listing-generating options - you can check that with man as.
objdump -S is an alternative that also works well in Linux, but Mac OS X's alternative to objdump is otool, which does provide disassembly but not source interlacing. Hopefully that will change soon-ish, because otool seems to be on its way out while llvm grows its own objdump. See man llvm-otool.
Finally, for OS X the best option seems to be using gobjdump -S, from binutils. It can be installed with MacPorts or brew.
You can Generate Assembly Code from a .cc/.cpp source file by using this command
clang++ -c -S test-function.cc
I have just downloaded clang 3.3 (homebrew) from the LLVM web page to my mac (OS X 10.8.4), but get this compiler error when using std=c++11 stdlib=libc++:
In file included from /usr/include/c++/v1/string:434:
In file included from /usr/include/c++/v1/algorithm:594:
In file included from /usr/include/c++/v1/memory:590:
In file included from /usr/include/c++/v1/typeinfo:61:
/usr/include/c++/v1/exception:146:5: error: an attribute list cannot appear here
_LIBCPP_NORETURN friend void rethrow_exception(exception_ptr);
^~~~~~~~~~~~~~~~
/usr/include/c++/v1/__config:190:28: note: expanded from macro '_LIBCPP_NORETURN'
# define _LIBCPP_NORETURN [[noreturn]]
^~~~~~~~~~~~
It seems that I also need another libc++ (even though it was said that it was 100% complete on MAC ...), but I cannot find any. Any help appreciated. Just for your info:
> clang++ -v
clang version 3.3 (tags/RELEASE_33/final)
Target: x86_64-apple-darwin12.4.0
Thread model: posix
And, yes, I googled it and found this: http://comments.gmane.org/gmane.comp.compilers.llvm.bugs/24138 claiming it's resolved in libc++ trunk ???
Okay, as suggested by Howard, I've downloaded tip-of-the-trunk libc++ into /opt/local/share/libcxx, but have trouble building it. The manual says to cd libcxx/lib, export TRIPLE=-apple-, and run ./buildit. I presume this implies bash (I'm usually a tcsh user, so I moved my .tcshrc, got a new shell and started bash). I did that and the compilations worked, but the library build failed. Apparently ./buildit doesn't see $TRIPLE=-apple-, as it picks the wrong LDSHARED_FLAG (not that on line 81, but that on line 103, which is to be used if $TRIPLE is not set), even though echo $TRIPLE yields -apple- as it should. When I add the statement echo TRIPLE = $TRIPLE at the top of buildit, it reports nothing. How come? What is wrong here?
The failure was that because the wrong LDSHARED_FLAG was picked the loading didn't work (ld complaint about the unknown option -soname which, I think, makes sense under linux). I don't know why buildit (a #! /bin/sh file) didn't pick up the TRIPLE environment variable (it did pick up several unwanted ones such as CXX and CC). I now simply added TRIPLE=-apple- at the top of that file and it did built the library. However, the loader spitted out several warnings all of which were of the form
ld: warning: direct access in ___cxa_bad_typeid to global weak symbol typeinfo for std::bad_typeid means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings.
But most importantly, it works (the compilation at least, I have yet to test the library). I have one final question. The advice was to use -I and -L to tell the compiler about the whereabouts of this version. Is it not possible to put it into the usual place /usr/include/c++/v1/? Note that Xcode has its version somewhere else anyway and I had put in a symbolic link (/usr/include/c++/v1/) to that one to get my homebrew clang 3.2 working (after the some Xcode update). What about the library? Can I also put it in a standard place?
Here is the home page of libc++:
http://libcxx.llvm.org
You can download the tip-of-trunk libc++ from there. You can tell clang to point to your download with -nostdinc++ -I<path-to-libc++>/include. You can also tell clang to link to your tip-of-trunk libc++ with -L<path-to-libc++>/lib and export DYLD_LIBRARY_PATH=<path-to-libcxx>/lib. The directions are all on the libc++ home page.
Xcode is the easiest way to get clang + libc++. But if you want the very latest, this is the place to go.
Congratulations!
Don't worry about the ld warning. It is a harmless ld bug that will be fixed in a future release. I see it on 10.8.4 too and it doesn't hurt anything.
The libc++ headers no longer live at /usr/include/c++/v1. Xcode has migrated them into itself. Having libc++ headers at /usr/include/c++/v1 from older installs has been a source of confusion and bugs. I regularly use -nostdinc++ -I to point to the libc++ headers I want (I often have several versions going at the same time), and that works well for me.
It is possible for you to replace your /usr/lib/libc++.1.dylib with that you have built. I do not recommend doing this. I have to sometimes to do a proper test, but I always do so very carefully because sometimes this causes me to have to reboot onto a backup disk and restore my /usr/lib to its original state. If you do go this route, it is a very good idea to have a backup of the original /usr/lib/libc++.1.dylib very handy.
I recommend instead -L on the command line, and export DYLD_LIBRARY_PATH=<path-to-libcxx>/lib in the shell. More than one person (including myself) has gotten their computer into a really nasty place by not following this advice.
If you run testit (under test/), all you need is DYLD_LIBRARY_PATH in that shell. The testit script is set up to point to the right places without an install.
Also I recommend figuring out why you had to modify buildit. No one else is seeing that behavior. printenv on your command line may help in this endeavor.
libc++ is updated often. We try to keep tip-of-trunk always in a shippable state.
I'd like to know in the code (.c file) how I can find the linux distribution name version (like ubuntu 10.0.4, or centOS 5.5...)?
The c function that I'm looking for should be like the uname() system call used in (.c files) to get kernel version.
it will be appreciated that the function is working for all linux distribution (standard)
I 'm not looking to get distribution name and version by the use of command line linux from code (.c file) (like the use of system("cat /etc/release");).
Any suggestion will be appreciated!
Regards
There is no standard for this yet. You can query following files or check for existence:
/etc/lsb-release
/etc/issue
/etc/*release
/etc/*version
Well, you can (and should) use fopen and fgets instead of system("cat"), for reading /etc/release.
There's no universal method though, I can even build a linux image which has no filesystem at all (except initramfs) and definitely no distribution name.
AFAIK there isn't a standard system call to get this if uname(2) doesn't give you enough info.
Safest approach is probably to check for "/proc/version" and read that
You could fopen("/etc/lsb-release") and parse its contents. It looks like this:
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=10.04
DISTRIB_CODENAME=lucid
DISTRIB_DESCRIPTION="Ubuntu 10.04.3 LTS"
This method is not universal. You'll need to make sure that it works on all distros that you care about (if it doesn't, I suggest you go with #ott--'s answer).
Is it acceptable to run some shell commands?
$ /usr/bin/lsb_release -r
Release: 11.04
$ /usr/bin/lsb_release -d
Description: Ubuntu 11.04
$ /usr/bin/lsb_release -rd
Description: Ubuntu 11.04
Release: 11.04
There is no portable way to do that, you'll have to use some OS detection tool/library.
Fortunately, there are a few out there. I know those 2 :
Facter, a professional (yet free/open) information gathering program in ruby : http://puppetlabs.com/puppet/related-projects/facter/
a shell script : http://www.novell.com/coolsolutions/feature/11251.html
(I used facter via puppet and it is very good.)
With a little additional scripting, you can use one of those program's output to generate a .h that you can then use in your code.
You can even integrate this generation as a step in your makefile.
I usually inspect /etc/issue; while (as others pointed out) it is not guaranteed, I've fount in the field that's quite reliable.
As far as I've experienced, it works on ubuntu, debian, redhat, centos, slackware and archlinux.