Toolchain Roadmap

Status

• Created: Date(2005-04-24T00:11:33Z) by MattZimmermanBR

• Priority: HighPriorityBR

• People: MatthiasKloseLead, JeffBaileySecondBR

• Contributors: MattZimmermanBR

• Interested: JimMcQuillan BR

• Status: BreezyGoal, UduBof, DistroSpecification, EditedSpecificationBR

• Packages: BR

• Depends: BR

• UduSessions: 1(0) BR

Introduction

Review toolchain status and strategy for Breezy

Rationale

• Much improved Java support
• Better error reporting from C and C++ front-end
• LSB 3.0 support
• Fortran 90 support
• Better optimizations from C compiler
• Faster compilation at -O0
• Better standards compliance

Scope and Use Cases

• gcc-4.0
• g++-4.0 and associated ABI transition
• glibc 2.3.5

Implementation Plan

Already done:

• Change "gcc" default to 4.0
• Change "g77" default to 3.4
• change "cpp" default to 4.0
• Upload glibc-2.3.5
• Change powerpc, ia64 to nptl-only

TODO:

• Details at http://www.ubuntulinux.org/wiki/BreezyToolchainTransition

• Upload g++-3.4, building g++ on amd64, defaulting to the new C++ ABI (1002).
• Change "g++" default to 4.0
  • Upload library packages, depending on libstdc++, rename library packages to deal with ABI break, as described on the Transition page.
  • For KDE, only rename libqt, as all other KDE packages depend on this library.
  • Upload all other packages depending on libstdc++, just recompiling, and/or applying outstanding bug reports including patches.
• Change "gcj", "gij" default to 4.0
• Enable ppc64 glibc (ready to upload)
• Change sparc to nptl-only
• Add to Breezy release notes intention to drop linuxthreads for remaining arch's.
• Drop gcc-2.95 (also means dropping chill)
• Look at tweaking gcc wrapper to look for archaic gcc build options (-O6, etc.)
• Binutils update (Sparc64 TLS support)
• Final massive rebuild to make sure that everything is builds correctly.
• Transition for non-release architectures (libgcc on hppa).

Data Preservation and Migration

glibc update can cause older applications to fail to run. Failures are usually linker-time failures, so low risk of runtime data loss.

Packages Affected

All packages to some degree:

• Poorly written C applications that don't work with stricter parser
• Poorly written C++ applications that don't work with stricter parser
• Renaming of library packages (about 100 in main, 300 in universe)

User Interface Requirements

N/A

Outstanding Issues

Coordinating with Debian - confirm that they will follow the same library rename plan. Proposal sent to debian-release, http://lists.debian.org/debian-release/2005/04/msg00153.html

UDU BOF Agenda

• Status update (some work will be done prior to UDU)
• C++ ABI transition plan (if transitions are still pending)
• libssp and GCC 4.0 ?

UDU Pre-Work

• Transition plan http://www.ubuntulinux.org/wiki/BreezyToolchainTransition

• Prepare packages of GCC-4.0 (currently in experimental), glibc (Done, uploaded)
• PowerPC64 biarch support

• Import of known FTBFS GCC-4.0 reports from unstable, for universe see http://www.ubuntulinux.org/wiki/UniverseCxxTransition (Done)

• Determine order of library updates