133 lines
4.3 KiB
Markdown
133 lines
4.3 KiB
Markdown
# GNU debugger
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<!--toc:start-->
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- [GNU debugger](#gnu-debugger)
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- [cheat sheet (nonexhaustive)](#cheat-sheet-nonexhaustive)
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- [reset program](#reset-program)
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- [TUI mode](#tui-mode)
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- [TUI keybindings](#tui-keybindings)
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- [navigation](#navigation)
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- [layouts](#layouts)
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- [source code view](#source-code-view)
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<!--toc:end-->
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## cheat sheet (nonexhaustive)
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> commands can be shortened
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>
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> e.g.: `b` for `breakpoint`
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| **command** | **description** |
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|:----------------------|:--------------------------------------------------|
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| `continue` | continue normal execution |
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| `break <position>` | set breakpoint |
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| `info breakpoint` | list breakpoints |
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| `delete <#breakpoint>`| delete breakpoint |
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| `step` | execute next instruction, then halt (step in) |
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| `next` | execute next instruction (step over) |
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| `finish` | execute until the end of the current function (step out) |
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| `backtrace` | show call stack |
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| `print[/format]` | show content of variable/memory location/register |
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| `x[/format] address` | print memory content at address |
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| `list <position>` | show file/lines/symbol in source code window |
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| `tui disable` | disable tui |
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| `tui enable` | enable tui |
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| `layout <layout>` | select specified layout |
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| `layout next/prev` | choose next or previous layout |
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| `focus <window>` | focus specified window |
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| **position** | **description** |
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|:----------------------|:--------------------------------------------------|
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| `<symbol-name>` | name of a symbol, e.g. function name |
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| `<line>` | line number (in current file) |
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| `<file>:<line>` | line number in the specified file |
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## reset program
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To reset the program one can use the following command
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```sh
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# reset program and halt execution
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monitor reset halt
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```
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## TUI mode
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The `GDB` comes with a Terminal User Interface (TUI) which provides view for
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the assembly, the registers and the source code.
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One can enable the TUI with `tui enable` or disable with `tui disable`.
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```sh
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# enable/disable TUI
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tui enable
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tui disable
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```
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### TUI keybindings
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| **Keybinding** | **Action** |
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|:---------------|:-----------------------|
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| `C-x,a/A/C-a` | toggle TUI mode on/off |
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| `C-o` | focus next window |
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### navigation
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One can navigate using the [keybindings](#tui-keybindings), but the easiest
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method is to use the `focus` command.
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The `cmd` window is the only one that accepts alphanumeric input, so regardless
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of the focused window, one can always use `focus <window>` to focus a specific
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window.
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### layouts
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One can choose various layouts with the following command:
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```gdb
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# choose layout, enable views
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layout <layout-name>
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# default layout options:
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# * asm
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# * regs
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# * src
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# * split
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```
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The `tui` command also allows to define custom layouts.
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See the example below.
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```gdb
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# defines a layout with the name `test` and the view `regs`, `src` and `cmd`
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tui new-layout test {-horizontal regs 1 src 2} 1 cmd 1
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# synopsis of `tui new-layout`
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tui new-layout <name> <view> <weight> [<view> <weight>]
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tui new-layout <name> {[-horizontal] <view> <weight> [<view> <weight>]} <weight>
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```
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### source code view
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The source code view - as the name suggests - displays source code.
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By default the window displays the file containing the current instruction,
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but one can choose a differnt file with the `list` command.
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Below are several examples of how to use this command.
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```gdb
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# when specifying a file, a line number is required
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list <file-name>:<line-number>
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# list knows symbol names
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list <symbol>
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list main # this will show the main function
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# show current execution point
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list .
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```
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