YDL.net

1 Introduction

The IBM XL C/C++ Compiler is a compiler that has been optimized for IBM Power systems. There are many benefits to using the XL C/C++ compiler, chief of which is a faster compiler time, especially for large C or C++ programs. The compiler is also capable of creating an optimization report which provides information about the optimizations that the compiler was able to perform as well as a list of optimizations that were missed, reducing the amount of time and effort spent tuning applications. It also includes support for loop optimizations, the Mathematical Acceleration Subsystem libraries, as well as support for the Vector Scalar eXtension that is a part of the POWER7 architecture.

1.1 This Guide to Installation

This Guide to Installation is written specifically for Yellow Dog Linux 7 and the IBM XL C/C++ Compiler version 12.1.

Refer to us.fixstars.com/support for updates, issues specific with computer configurations, and engineering notes.

2 Installation

To install the XL C/C++ Compiler on Yellow Dog Linux you can use the xlc_install utility that comes with the compiler. First you will want to become root user. Then you want to make sure that all of the following prerequisite packages are installed. To install ppc64 packages use the `yum install ` command. To install ppc packages, append `.ppc` to the package name. For example, to install the ppc version of libgcc you would enter `yum install libgcc.ppc`.

Package Requirements		Architectures
	gcc-4.4.6	ppc64
	gcc-c++-4.4.6	ppc64
	glibc-2.12	ppc & ppc64
	glibc-devel-2.12	ppc & ppc64
	libgcc-4.4.6	ppc & ppc64
	libstdc++-4.4.6	ppc & ppc64
	libstdc++-devel-4.4.6	ppc & ppc64
	compat-libstdc++-33-3.2.3	ppc & ppc64
	perl >= 5.0	ppc64

2.1 Using xlc_install

Once all of these packages are installed then you are ready to run the xlc_install utility. This utility will:

Check for all prerequisite packages
Uninstall any previous versions of XL C/C++
Install all packages into the default location, which is /opt/ibmcmp/
Automatically invokes the new_install utility, which installs the license file and generates the default configuration file.
Optionally creates symbolic links in /usr/bin/ to the compiler invocation commands
Generates an installation log in the /tmp/ directory

Once you have downloaded the package you will have to unpack it. You can do this by using the following command:

tar -xzf filename

Now you should be able to run the ./xlc_install utility to begin installing the XL C/C++ Compiler. If you have a previous version of XL C/C++ installed or if you have installed the XL Fortran compiler then you will be asked if you wish to continue the installation during the SMP and MASS version check. You will be asked to review and accept/decline a license agreement. The installer will also ask if you wish to create symbolic links for the compiler invocations in /usr/bin/, making it a bit more convenient to invoke the compiler. If all packages are successfully installed then a message is displaying confirming that the compiler install was completed.

2.2 xlc_install Options

Install Options
	-h	Displays the installation utility help page.
	-prefix installation_path	Explicitly specifies the path to install all the compiler packages. NOTE: If this option is not used the default installation location is /opt/ibmcmp/
	-rpmloc rpmlocation_path	Explicitly specifies the path where all compiler packages are located. The default rpmlocation_path is ./images-x86/rpms or ./images/rpms, which is relative to the path of the installation tool. NOTE: For most users the -rpmloc rpmlocation_path option is not required in the installation invocation. If you use the utility directly from the CD or electronic image it will automatically determine the source location of the packages.
	-U	Updates the compiler to the Version.Release.Modifications.Fix-Build (V.R.M.F-B) level that the installation utility version supports.
	-v	Displays debugging information generated during the installation of the compiler.
	-vv	Displays extra debugging information generated during the installation of the compiler.

3 Usage

To invoke the compiler for a C program, use the command xlc input_files. For a C++ program use the command xlc++ input_files. If any of your source files are C++ then you must use this invocation to link with the correct runtime libraries. Files with .c suffices, assuming you have not used the -+ compiler option, are compiled as C language source code.

4 Conclusion

The This guide covers the basic installation and invocation of the IBM XL C/C++ Compiler. More in-depth usage information can be found in the XL C/C++ Compler Reference which can be found here:

http://www-01.ibm.com/support/docview.wss?uid=swg27024742

Once you understand the basics you may wish to read the Optimization and Programming Guide to get the most out of your program:

http://www-01.ibm.com/support/docview.wss?uid=swg27024743