Dbx: Articles, news, notes on dbx, the Sun Studio debugger and other stuff.

Every now and then a problem about linking is reported on Sun Studio forums. Sometimes the problem is that users try to invoke ld, the link-editor, directly, instead of using compiler driver (CC, cc, f90, f95, ...). I'd like to shed some light on the subject and illustrate the difference.[Read More]

In this post I'm going to try to collect most useful and commonly used ~/.dbxrc settings. I'll start with contents of my ~/.dbxrc file with probably most popular aliases in hope for comments and additions.

I encourage you to share functions, aliases, useful dbxenv settings that make your dbx a better debugger.

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All Sun Studio distributions [that I am aware of] contain a utility program named dwarfdump; as is apparent from its name, dwarfdump can print DWARF information contained in an ELF executable or shared object. There also exists third type of ELF files - relocatable files; those are object files (.o) produced by a compiler that can be linked together to produce another relocatable file (.o) or executable/shared library.

One would expect dwarfdump to handle all types of ELF files, but until recently, dwardump would often crash when dumping debug information of a relocatable file on x64 and sparcv9 binaries. In this post I'll explain the reasons for crash and why relocation records processing is important when reading DWARF.

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Separating debug info from the executable or shared library decreases its size by several times while preserving full debuggability on demand. This post describes simple procedure of creating separate debug info files.[Read More]

In this post I describe fairly recent and little known dbx feature  - support of separate debug info files through .gnu_debuglink section. This feature was introduced with dbx 7.7 (part of Sun Studio 12) and backported to earlier releases (you have to have latest patch for dbx earlier than 7.7). It is probably most useful on Linux systems where one can easily install packages with the debug info for virtually anything.

Here I'll describe how to step into a random libc function with the source code.

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A new set of cheatsheets, now with rather frequently used utilities for ELF files examination. Includes nm, readelf, pvs and a bunch of other useful programs:

NOTE: .svg files are saved as "Inkscape SVG" and are intended to be edited in Inkscape, not to be viewed by common image viewer (which may display garbage instead of some elemets).

Refs:

• Linker and Libraries Guide - Solaris 10 edition of a classic volume.

I don't use mdb in my everyday work, however sometimes it is not only useful, but essential - when you have to debug at low level, which dbx tends to hide from you (for example, dbx usually can't display stack trace past main()). So here are a few commands that I find useful:

NOTE: .svg files are saved as "Inkscape SVG" and are intended to be edited in Inkscape, not to be viewed by common image viewer (which may display garbage instead of some elemets).

Refs:

• Modular Debugger (mdb) cheatsheet - more thorogh version that my drawings.
• Solaris Modular Debugger Guide - official document from docs.sun.com

I got tired of looking up what this or that SPARC instruction means and where to find %fp register value when you're in a leaf procedure, so I decided to prepare a few small cheatsheets that have this kind of information in very compact form.

I'm posting PDF and source svg here in hope that this info will be useful for other people as well. Anyone's welcomed to download/print/modify those.

NOTE: .svg files are saved as "Inkscape SVG" and are intended to be edited in Inkscape, not to be viewed by common image viewer (which may display garbage instead of some elemets).

Refs:

• SPARC Assembly Language - very useful, minimum to no "syntactic sugar", pure information.
• A Laboratory Manual for the SPARC - older, longer reading, but has more coding examples.
• Technical SPARC CPU Resources - lots of links to other pages. Explore the Web.
• SPARC Architecture Manual, Version 9 - ultimate source of information, comes in PDF form.

На сайте developers.sun.ru появилась статья на практически вечную тему - увеличение производительности за счет лучшего использования процессорного кэша. Обычно под этим подразумевается оптимизация доступа к кэшу данных (поскольку управлять доступом к данным автору программы проще); в этой же статье даются советы по более эффективному использованию кэша инструкций, который больше доступен авторам компилятора и компоновщика, чем прикладным программистам. Полное название статьи - "Улучшаем производительность приложения путем перераспределения кода".

На сходную тему есть также статьи на английском языке:

• http://developers.sun.com/solaris/articles/Feo/feo_content.html - статья, в основном, о том как лучше использовать кэширование данных процессором;
• http://blogs.sun.com/solarisdev/entry/new_article_prefetching - как пользоваться прагмами для упреждающей выборки данных (prefetching).
  

Страница с вопросами и ответами о Sun Studio  -- на русском языке и с актуальной информацией.

 Я перевел существующий FAQ о Sun Studio Криса Квенелли, а заодно и обновил содержащуюся там информацию (во время составления оригинального FAQ актуальной была версия 11, теперь же последняя версия Sun Studio - 12).

Недавно открылся портал разработчиков Sun, содержащий информацию о массе технологий и продуктов, включая высокопроизводительные вычисления, Солярис, DTrace, ZFS и проч. связанные материи, а также Sun Studio - компиляторы C, C++, Fortran и инструменты для разработчиков. На сайте уже есть и будут появлятся новые статьи, анонсы и прочие материалы, нужные разработчикам для линукса и соляриса.

Сейчас на странице о Sun Studio представлены следующие материалы:

• Обзор Sun Studio со скриншотами среды разработки,
  
• Статья "Поиск ошибок доступа к памяти с использованием Sun Memory Error Discovery Tool"
  
• Статья "Отладка AMD64 на уровне машинного кода с помощью отладчика dbx"
  
• Введение в OpenMP: API параллельных программ для многопроцессорных систем с общей памятью
• Замечания о переходе с модели данных ILP32 (32-битный приложения) на  LP64
  

и другие статьи и новости о технологиях Sun в области разработки ПО.

A table displaying correspondence between gdb and dbx commands, similar to one found in dbx `help FAQ', but a lot larger.[Read More]

This post describes setup and (mostly) configuration of Nexenta OS on an W2100z Opteron box.

My configuration (most important parts):

• Static IP address
• Machine is in NIS domain

I used latest unstable version - alpha 7 test 2, which is based on build 61 of OpenSolaris.[Read More]

Перевод статьи http://developers.sun.com/prodtech/cc/articles/ILP32toLP64Issues.html

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Some notes on upcoming  dbx 7.5 patch 121023-02 (sparc). Two important Run-Time Checking feature fixes.

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