I'm working on a migration task from a GNU to a LLVM compiler.
The first question is, how to deal with Makefile in an existing project.
What is the counterpart to make.exe of GNU?
Related
I'm trying to figure out the compiler versions that are used in my project (to sync them across the team).
I'm using ChibiOS on an STM32 and it uses a makefile to compile. In the Makefile it uses
TRGT = arm-none-eabi-
CC = $(TRGT)gcc
Which makes it clear that arm-none-eabi-gcc is being used. However unclear to me is, if the version of my gcc compiler (gcc --version) is at all relevant to the compilation. As far a I understand gcc just is being set to a specific target here? Whats the relationship between my gcc/cc executable and the arm-none-eabi-gcc executable?
There is no relationship. It is a separate compiler which usually comes with its own include files, libraries, startup file and linker scripts. Usually, it is called a toolchain as often it comes with other tools as well (linker, specific versions of gdb and other tools).
I am new to porting gcc, just want to ask, if I only want gcc to generate assembly language for each files can I skip porting Binutils ?
Sure. Are you trying to port gcc as cross-compiler? You should configure with --disable-bootstrap and use make all-gcc when building it (i.e. skip libgcc, glibc, libstdc++ build). Then you will get pure compiler to work from source to target assembler only.
I'm trying to compile a project from the command line. The default compiler LLVM-clang and i need to compile with LLVM-gcc42. Switching a compiler in Xcode is really easy. However, on command line it seems to be more problematic. To my understanding "/usr/bin/cc" and "/use/bin/gcc" are used for pointing c/c++ compilers. I noticed that "cc" was linked to "clang" in same directory. So, i changed "cc" to point at "gcc". Did not helped. When i run
$ gcc -v
i get response
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn)
Target: x86_64-apple-darwin12.5.0
How do i change the clang to gcc?
My setup is:
MAC OS X 10.8.5
Xcode 4.6.2
Command line tools
EDIT 13.02.2014
The project is a QT project which uses mixture of third party c/c++ libraries. My task is to write a new objective C lib to it. The project is build with -spec macx-g++ parameter. The configuration scripts can be found /QTROOT/mkspecs/macx-g++ and /QTROOT/mkspecs/common. In g++-base.conf key variables are defined as:
QMAKE_CC = gcc
QMAKE_CXX = g++
Instead of changing links which can affect other programs use the full path to the llvm executables in your build script
e.g. if you have installed the command line tools
QMAKE_CC = /usr/bin/llvm-gcc-4.2
QMAKE_CXX = /usr/bin/llvm-g++-4.2
Okay, nailed the problem. Solution was simple. I deleted the old links from /usr/bin/gcc and /usr/bin/g++ and created new ones pointing to the proper compilers.
gcc -> /Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2/bin/llvm-gcc-4.2
and
g++ -> /Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2/bin/llvm-g++-4.2
I would like to set g++4.8 as the c++ compiler with qt creator.
I am in a OSX 10.8, QtCreator 2.8.0, and I have installed g++4.8 via homebrew.
I have setted the g++4.8 as the compiler: if I go in Projects > Manage Kits I have the GCC kit as default, and manually inserted a compiler called GCC 4.8, with compiler path /usr/local/Cellar/gcc48/4.8.1/bin/g++-4.8.
You can see it in the screenshots below. I also have /usr/local/Cellar/gcc48/4.8.1/bin in the Build Enviroment > PATH.
But, if I add QMAKE_CXXFLAGS = --version (I know it is dumb and it doesn't compile but it is just for testing) I receive in the "compiler window"
i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1
(that is the same output i receive if I launch g++ from the shell) and not
g++-4.8 (GCC) 4.8.1
(that is what i receive if I launch /usr/local/Cellar/gcc48/4.8.1/bin/g++-4.8 from the shell) (and it is what I want too)
I remember that I had this problem in the past, I tried to resolved it hardlinking the g++4.8 to /usr/bin/g++ but it was not resolved (and just messed up everything).
What can I do?
I had the same problem and landed on your question...
Your question is how to make Qt Creator to use g++-4.8 for compilation.
The solution I devised is the following:
Solution
Add the following line somewhere in your project.pro file
QMAKE_CXX = g++-4.8
for instance just above the HEADERS list
Rationale:
The makefile synthesized by qmake uses the variable CXX to determine the C++ compiler.
You can set the value of the variable CXX at the level of the project configuration file by manually editing it.
Pros:
It solves your problem, you will compile your project using g++-4.8 without having to change the g++ compiler for the rest of your environment.
Cons:
You have to manually set that for each project.
Question for Qt developers:
is there a more natural way to set the g++ compiler at the Kit level? If there is not way, that might be a useful functionality to add.
Is there an option to GCC that changes the path of the assembler it uses? I'm getting errors from Solaris /usr/ccs/bin/as when using GCC to attempt to compile Haskell, but I've got a copy of GNU as in my path so when I type which as and as --version they use the GNU version, not the Solaris version. Unfortunately it seems GCC ignores the GNU version in the path and goes to the Solaris version. I'm trying to build Haskell on Solaris and I don't think it sits well with the Solaris assembler. I hope I can change this behaviour with a simple wrapper script so I don't have to recompile GCC.
Specifying the assembler to be used is not possible at run time. It has to be done when configuring gcc:
--with-gnu-as
Specify that the compiler should assume that the assembler it finds is the GNU
assembler. However, this does not modify the rules to find an assembler and will
result in confusion if the assembler found is not actually the GNU assembler.
(Confusion may also result if the compiler finds the GNU assembler but has not
been configured with --with-gnu-as.)
Note the part I've put in italics. Of course you could temporarily change /usr/ccs/bin/as to call the gnu assembler (provided you have the necessary permissions), but the above seems to suggest that you'll very likely run into problems. The gcc build process actually checks the features the assembler supports and generates code for exactly that assembler.
I suggest you build a new version of gcc first (configured to use the gnu tools), and then use that to build ghc.