I'm currently managing some C++ code that runs on multiple platforms from a single source tree (Win32, Linux, Verifone CC terminals, MBED and even the Nintendo GBA/DS). However I need to build an app targetted at an embedded platform for which there is no C++ compiler (C only). I remmber that many of the early C++ compilers were only front-ends stitting on existing C compilers (Glockenspiel for example used MSC). Are there any such 'frontend' C++ compilers in use today that will generate C code.
Tools Platform
----------- ------------
______Visual C++ _____ WIN32
/
/_______MBED (ARM)_______MBED (ARM dev board).
/
/_________GCC (x86)________Linux
/
Source____/___________GCC (ARM)________GBA/DS
\
\__________SDA______________Verifone Verix CC Terminals
\
\________ARM SDT__________Verifine VerixV CC terminals
\
\______????_____________Renases M8/16/32.
\
\____????_____________Z8 family.
The last two platforms I have good C compilers for but no C++.
As you can see I'm supporting a large variety of platforms and I share a large body of library code (and some app code).
If you use LLVM, llvm-g++ will compile your C++ code to LLVM bitcode, and llc has a backend which converts bitcode to C.
You could write commands like this:
llvm-g++ -emit-llvm -c foo.cpp -o foo.o
llc -march=c <foo.o >foo.c
Comeau C++ does this.
Can't help with the Z8, but the Renesas M16C/M32C family has GCC these days - see http://www.kpitgnutools.com/ for prebuilt cross toolchain hosted on Windows. Haven't used it myself yet but may be a better option than a 3rd party C++ frontend, especially as your code already targets GCC on other platforms.
Comeau C++ generates C as its output, and they seem to be quite happy to port it to work with different back-end compilers, though I'm not sure about the exact pricing for that.
If you want a bit more of a "roll your own" approach, you could buy a license to the EDG C++ compiler. It's normally used as a front-end (e.g. by Comeau and Intel) but I believe as it's shipped, it includes a code generator that produces C as its output. Its licensing is oriented more toward compiler vendors, though, so a license gives you a lot of rights, but is pretty expensive.
Out of date, but maybe you want to try cfront?
I'll leave this for information - cfront doesn't have exception support.
Of what I have understood, the c++ support in gcc for r8c/m16c/r32c isn't quite mature and good enough for production code. But for r8c/m16c/m32c/r32c there is at least one compiler supporting embedded C++ and that is IAR, I think Tasking also supports embedded C++ on m16c.
Notice that the valid solution is for llvm 1.3
llvm last release was 6.0.0 so it would'nt work at all.
(I post this because i've try the solution of this post but it doesn't work anymore) (Maybe i've done something bad)
In my tests llc do not accept anymore the -march=c option.
And going back to the 1.3 isn't possible for me yet.
So try to take care about the version.
Related
Hi I`m looking for a library in c++ which i compile with the borland compiler bcc32.
Before I tried to take the benefits of RInside but unfortunately it´s only working with gcc-compiler and can´t be used in my programming environment, wich is Embarcadero.
Is it possible to use Rcpp with a bcc32 compiler?
Are there compatitible librarys on the market doing statistical calculations in c++
I hope you can help me. Thanks.
Part 1: no. From the Rcpp FAQ:
1.3. What compiler can I use. On almost all platforms, the GNU
Compiler Collection (or gcc, which is also the name of its
C language compiler) has to be used along with the corresponding
g++ compiler for the
C++ language. ...
The
clang
and
clang++
compilers from the LLVM project can
also be used ...
The Intel
icc
family has also been used successfully as its output
files can also be combined with those from
gcc
.
If it's not on that list, it's not supported.
Part 2: off topic for StackOverflow.
I read about tool called "include-what-you-use" which can help clean superfluous includes
from source code. I understood that there is a version for compiler LLVM(clang) and version for GCC.
My questions are:
Why this tool is compiler-dependent and not "cross-platform" for compilers. Why from the beginning the creators of the tool didn't make it compiler-independent? Is it related to the special implementation it has or something like that?
If I want to take a version of the tool compatible for LLVM and I want to make it compatible with GCC (since I'm working with GCC), what do I have to do for that?
For the most part, Include-What-You-Use should be able to handle any valid C++ codebase, regardless of whether that codebase was written with gcc or clang in mind. I recently had the occasion to run Include-What-You-Use on a very large codebase that was usually compiled with gcc and it worked fine. So in that sense it is already compatible.
That said, it might not work perfectly. It's likely that some of the information it provides will be wrong, even if it's a clang codebase. So always verify the output manually.
why this tool is compiler-dependent and not "cross-platform" for compilers. Why from the beginning the creaters of the tool didn't make
it compiler-independent ? is it related to the special implementation
it has or something like that ?
Reason is simple, clang has is more modern fresh and has better modular architecture. As a result is is much easier to create tools using clang modules.
That is why clang was first which had address sanitizer and have more cool sanitizers. And this is why when someone creates new tool for C++ stars from clang.
If i want to take a version of the tool compatible for llvm and i want to make it compatible with gcc(since i'm working with gcc). What
i have to do for that ?
clang was created since Apple was not happy with gcc. So when it was written it supposed to be as much compatible with gcc as possible, since there was lots of code which was verified with gcc.
Since clang is mature now and provides new own features, there might be small differences with gcc (for example different bugs in implementations of new C++ standards), but in most common code there should be no problem.
IWYU should work without problems on both compilers. My coworker used it on large project build with 3 compilers (clang, gcc and VS) and it worked like a charm.
The tool itself needs parts of the compiler! It is sitting somewhere between reading the source and parsing it. LLVM provides an API which is used for the tool. The tool itself is not standalone but a plugin to the clang/llvm. As this, it needs the clang/llvm.
The modifications which will be done by the tool are fully compatible to every c++ compiler. And also the plugin in combination with clang/llvm should be able to parse more or less every code base independent of used other compilers. There might be some strange macros which are supported by other tool chains, which llvm might be struggle with. But that should be a rare case at all.
My university professor has given a requirement for us in his c++ class: We must write our programs using the gnu C++ compiler (GCC). I understand that after installing xcode, I get an apple version of gcc. However, this is not fully cross compatible as I understand. So I have tried to install the gnu gcc compiler by using mac ports, but I have been unsuccessful. After doing:
port install gcc47
When I go to the terminal and run:
gcc47 -v
I get "command not found"
When I run:
gcc -v
I get:
gcc version 4.2.1 (Apple Inc. build 5666) (dot 3)
Showing that I am still using apple's version. The part I am not understanding is:
How do I install gcc (the gnu version, not apple's version)
How do I use it with an ide, such as eclipse?
The version of GCC you use (Apple or gnu native) should be irrelevant for you to proceed.
Writing portable C++ has nothing to do with the compiler--outside of ensuring your compiler does it's best to adhere to the C++ standard. Luckily enough, GCC is one of the best C++ compilers out there.
You're not looking to do cross-platform C++ per-se, because true portable C++ is somewhat of a pain to write given the various state of C++ compilers for various systems (for example the CC on VAX/VMS doesn't support templates...). I suspect what you want to do is ensure the code you write on your mac, can be compiled by your prof. As long as GCC can handle it on your mac, it should be fine.
So to your specific questions:
Your first question is unnecessary, as you can use apple's supplied g++ to compile your code.
For your second question, I would highly recommend against using an IDE while trying to learn. IDE's offer some really great time saving features, but they hide some important aspects, that I believe are worth struggling with early in your learning process, and which will help strengthen your C++ skills. And while things have certainly have gotten better, some IDE's were notorious for creating non-portable C++ (ie using void main()).
If you are still set on using Eclipse, or XCode, since it doesn't matter which GCC installation you use, the default setup should work just fine.
I've run into troubles installing gcc47 via ports in the past, but gcc46 went as expected. You may also want to install gcc_select.
From there, you can use gcc_select, or specify the path explicitly in Eclipse's toolchain editor.
Other notes:
If you don't need C++11 features, then Apple's GCC 4.2.1 should work fine. Perhaps you can detail why you can't use it. Basically, Apple's added some extensions to the toolchain in some cases (marked APPLE_ONLY), and you have good control of what options are enabled/disabled.
Recent versions of Clang which ship with Xcode handle C++ well (including some support for C++11). There are some advanced things in GCC that I miss when using Clang, but Clang's current C++ support is really quite good.
For my own education I am curious what compilers use which C++ front-end and back-end.
Can you enlighten me where the following technologies are used and what hallmarks/advantages they have if any?
Open64 - is it back-end, front-end, or both? Which compilers use it? I encounter it in CUDA compiler.
EDG - as far as I can tell this is a front-end use by Intel compilers and Comeau. do other compilers use it? I found quite a few references to it in boost source code.
ANTLR - this is general parser. Do any common compilers use it?
Regarding compilers:
with front-end/back-end does gcc compiler suite uses? does it have common heritage with any other compiler?
what front-end/back-end PGI and PathScale compilers use?
what front-end/back-end XL compiler uses (IBM offering).
in-depth links on the Internet or your personal know-how would be great.
I did some Google searching, but information I generally encountered was rather superficial.
Thanks.
EDG is a front-end used by Intel and Comeau. See EDG's list of customers for other users.
ANTLR is a parser generator. I'm not aware of any C++ compiler built around a parser that was built with ANTLR (that doesn't mean it couldn't exist though).
GCC is a suite of compilers, with front ends for C, C++, Fortran, Ada, Java, etc., and back-ends for more processors than I'd care to think about.
Open64 is also a suite of compilers including several front-ends (for C, C++, Fortran, and possibly others I don't remember at the moment) and back-ends (targeting X64, Itanium, ARM, and, again, probably others I don't remember and/or don't know about). I believe its origin (pun noted by not intended) is SGI's compiler(s). I seem to remember reading something hinting that Open64 was derived from some version of the GCC front end(s), but offhand I don't know 1) how similar it remains to GCC internally, or 2) the version of GCC from which it derived -- but it's been around long enough that I'd guess it was GCC 3.x at the most recent, and quite possibly GCC 2.x.
I believe PathScale has created at least one compiler derived from Open64, but they may have others as well.
As far as I know, IBM's compiler is entirely their own creation. I'd guess IBM's (now discontinued) VisualAge for C++ shared some heritage/development/code with XL C++, but don't know that for sure, and can't even begin to guess at the extent of it, even assuming it's true.
The Clang project provides new front-ends for C/C++/Objective C on top of the LLVM backend. The LLVM project also provide a LLVM-gcc, using the GCC front end and the LLVM backend. The DragonEgg project seeks to replace the GCC backend with LLVM.
The Codeplay VectorC, Sieve and Offload compilers use a custom front-end and back-end
with front-end/backend does gcc compiler suite uses? does it have common heritage with any other compiler?
The acronym “GCC” stands for “GNU compiler collection” (originally “GNU C compiler”) and this already gives a hint: GNU compilers are a collection of compilers, most notably for C and C++ but also for Fortran, Objective-C and others. They share a common back-end and intermediate representation that was developed for GCC specifically.
The front-ends are all custom-written for the GCC. Some were contributed by third parties, most notably the Objective-C front-end, which was contributed by Apple.
Visual studio uses EDG for its intellisense engine.
Are there c++ compilers that I can run on a brand x system that will create machine code that will run on a brand y system? Would this be considered a cross compiler?
Yes, that's exactly what a cross compiler is.
The GNU Compiler Collection (which includes gcc and g++) are a prime example of a portable cross compiler with hundreds of supported CPU types.
There are many ways to configure GCC to be a cross compiler. Most of it depends on the target machine and what's available from it - mostly because of the C runtime environment. For example, compiling GCC for an ARM Linux target requires an ARM Linux glibc pre-compiled to build the cross compiler libstdc++.
This is quite common using gcc.
There are a number of tutorials around that describe building your own cross-compiler environment.
This is one, but a quick google will probably provide a link to someone doing exactly the mix of environments that you're after.
edit:
This is a more thorough tutorial, using crosstool
Yes there are such compilers; yes, they are called cross compilers. For example, GCC can be configured in this manner, so that I can run the compiler on a 32-bit x86 system, but produce 64-bit code for an x64 system, and that's just the tip of the iceberg.
Crosstool is a really handy tool suite for creating a cross-compiling GCC.
HTH,
Eric Melski
Electric Cloud, Inc.
Yes this is what cross-compilation is about (although I would say "brand X" isn't appropriate classification term).