Introduction

-4 -2006-01-30 +5 +2006-02-02 Introduction @@ -54,11 +53,20 @@

This guide will document the necessary steps required to perform a seamless -upgrade of the compiler used by your Gentoo box. A specific section is dedicated -to the upgrade from GCC 3.3 to the 3.4 -version and issues with libstdc++. +upgrade of the compiler used by your Gentoo box. A specific section is +dedicated to the upgrade from GCC 3.3 to 3.4 or +greater versions and issues with libstdc++. A second specific +section is for users first installing Gentoo +using a stage3 tarball, after a new GCC major/minor version has been released.

+ +It should be noted that upgrading from GCC-3.4 to GCC-4.0 or greater requires +no real changes to be made by the user, as GCC-3.4 and GCC-4.0 use the same +ABI. All that is required is that gcc-config is used to select the +compiler desired. + + @@ -70,8 +78,14 @@ -If you're looking for instructions specific to upgrades from GCC-3.3 to -GCC-3.4, please consult the dedicated +If you're looking for instructions specific to upgrades from GCC-3.3 to GCC-3.4 +or greater, please consult the dedicated +section. + + + +If you're looking for instructions specific to upgrades in GCC for new +installs, please consult the dedicated section. @@ -114,8 +128,8 @@

-It is safe to remove older GCC version at this time. If you feel the -need, please issue the following command (as usual, substitute +It is safe to remove the older GCC version at this time. If you feel the need, +please issue the following command (as usual, substitute =sys-devel/gcc-3.3* with the version you want to uninstall):

@@ -128,15 +142,15 @@ -Upgrading from GCC-3.3 to 3.4 +Upgrading from GCC-3.3 to 3.4 or greater

Introduction

-The upgrade from GCC/3.3 to 3.4 is not so seamless as the C++ ABI changed -between these two versions so there is an issue with libstdc++ library -which must be taken care of as well. +The upgrade from GCC-3.3 to 3.4 or greater is not seamless as the C++ ABI +changed between these two versions. There is an issue with the libstdc++ +library which must be taken care of, as well.

@@ -153,12 +167,13 @@

-You have two possibilities on how to upgrade your system. First method is faster and -requires use of revdep-rebuild tool from package gentoolkit while -the second one rebuilds the +You have two possibilities on how to upgrade your system. The first method is faster and +requires use of the revdep-rebuild tool from package gentoolkit +while the second one rebuilds the entire system from scratch so it will make use of new GCC features. It's up to -you to decide which of these two ways you will choose. +you to decide which of these two ways you will choose. In most cases, the first +method is sufficient.

@@ -320,10 +335,10 @@

-If a package fails during emerge -e system/world, you can resume -operation with emerge --resume. If a package fails repeatedly, skip it -with emerge --resume --skipfirst. Don't run any other instances of emerge -in between or you will lose the resume information. +If a package fails during emerge -e system or emerge -e world, +you can resume operation with emerge --resume. If a package fails +repeatedly, skip it with emerge --resume --skipfirst. Don't run any +other instances of emerge in between or you will lose the resume information.

@@ -341,6 +356,152 @@

+ + + +Upgrading to GCC on a First Install +

+Introduction + + +

+A GCC upgrade on a system after installation from a stage3 tarball is a simple +affair. One advantage users of new installations have is they do not have a +plethora of software installed that links against the older version of GCC. +The following example is for a GCC-3.3 to 3.4 or greater upgrade. Certain parts +will be different if upgrading from other versions of GCC. For example, the +library names used for revdep-rebuild below are GCC 3.3 specific, as +well as the need to install libstdc++-v3. +

+ +

+If a user has not made any customizations to their system yet, then there are +very few steps to get their system upgraded to a new GCC version. As with the +GCC-3.3 to 3.4 upgrade, the user has a couple options. However, unlike the +GCC-3.3 to 3.4 upgrade, this one is less complicated as there are fewer +differences between the methods. The first method is faster and makes use +of the revdep-rebuild tool from gentoolkit, similar to the above +procedure. Using revdep-rebuild causes only packages which actually link +against GCC libraries to be rebuilt, while the second method causes your entire new +install to be recompiled with the new GCC version and takes much longer. This +second method is never required and only documented for completeness. +

+ +

+These first steps are common between both methods, and should be completed by +everyone. +

+ +

+# emerge -uav gcc
+# gcc-config i686-pc-linux-gnu-3.4.4
+# source /etc/profile
+
+(Rebuilding libtool)
+# emerge --oneshot -av libtool
+

+ + +This assumes that you have CHOST="i686-pc-linux-gnu" set. If you are +using another CHOST, please use the appropriate gcc-config line. + + +

+To provide compatibility with older binary C++ applications, +sys-libs/libstdc++-v3 needs to be merged onto your system. +

+ +

+# emerge --oneshot sys-libs/libstdc++-v3
+

+ + +

+ +

+Using revdep-rebuild + + +

+This method requires that you first install gentoolkit if you have not +already done so. We will then run revdep-rebuild to actually scan the +installed packages for ones we need to rebuild, then rebuild them. +

+ +

+# emerge -an gentoolkit
+# revdep-rebuild --library libstdc++.so.5 -- -p -v
+# revdep-rebuild --library libstdc++.so.5
+

+ + +It is possible that you might have problems with non-existing package versions +due to them being outdated or masked. If this is the case, you will want to use +the --package-names option to revdep-rebuild. This causes packages +to be recompiled based on the package name, rather than the exact name and +version. + + + +

+Using emerge -e + + +

+This method, while much slower, will rebuild the system target to ensure that +everything has been rebuilt with your new compiler. This is not necessary, but +is valid if you are also making changes to CFLAGS or other make.conf variables +that will affect the system compile. +

+ +

+# emerge -uav gcc
+# gcc-config i686-pc-linux-gnu-3.4.4
+# source /etc/profile
 
+(Rebuilding libtool)
+# emerge --oneshot -av libtool
+

+ + +This assumes that you have CHOST="i686-pc-linux-gnu" set. If you are +using another CHOST, please use the appropriate gcc-config line. + + +

+To provide compatibility with older binary C++ applications, +sys-libs/libstdc++-v3 needs to be merged onto your system. +

+ +

+# emerge --oneshot sys-libs/libstdc++-v3
+

+ +

+Since we are performing these actions after an initial installation, we do not +need to recompile the world target as we would when doing an upgrade on an +already installed system. However, you may choose to perform a world update in +place of the system update, to ensure that all packages are updated. +

+ +

+# emerge -e system
+

+ +

+It is also safe to remove older GCC versions at this time. Since this is an +initial installation, we are using portage's prune feature to remove all older +versions of GCC. +

+ +

+# emerge -aP sys-devel/gcc
+

+ + +

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