Debugging with GDB (February 2008)

ManualsBrandsHP ManualsSoftwareHP-UX Debugging Tools

171

172

173

174

175

176

177

178

179

180

Table Of Contents

Summary of GDB
- Free software
- Contributors to GDB
A Sample GDB Session
- Loading the Executable
- Setting Display width
- Setting Breakpoints
- Running the executable under GDB
- Stepping to the next line in the source program
- Stepping into a subroutine
- Examining the Stack
- Printing Variable Values
- Listing Source Code
- Setting Variable Values During a Session
Getting In and Out of GDB
- Invoking GDB
- Quitting GDB
- Shell commands
GDB Commands
- Command syntax
- Command completion
- Getting help
Running Programs Under GDB
- Compiling for debugging
- Starting your program
- Arguments To Your Program
- Program Environment
- Working directory
- Program Input and Output
- Debugging a Running Process
- Killing the child process
- Debugging programs with multiple threads
- Debugging programs with multiple processes
Stopping and Continuing
- Breakpoints
- Continuing and stepping
- Signals
- Stopping and starting multi-thread programs
Examining the Stack
- Stack frames
- Stacks Without frames
- Commands for Examining the Stack
- Backtraces
- Selecting a frame
- Information about a frame
Examining Source Files
- Printing source lines
- Searching source files
- Specifying source directories
- Source and machine code
Examining Data
- Expressions
- Program variables
- Artificial arrays
- Output formats
- Examining memory
- Automatic display
- Print settings
- Value history
- Convenience variables
- Registers
- Printing Floating Point Values
- Floating point hardware
Using GDB with Different Languages
- Switching between source languages
- Displaying the language
- Type and range checking
  - An overview of type checking
  - An overview of range checking
- Supported languages
  - C and C++
  - Fortran
Examining the Symbol Table
Altering Execution
- Assignment to variables
- Continuing at a different address
- Giving your program a signal
- Returning from a function
- Calling program functions
- Patching programs
GDB Files
- Commands to specify files
- Specifying shared library locations
- Errors reading symbol files
Specifying a Debugging Target
- Active targets
- Commands for managing targets
- Choosing target byte order
HP-UX Configuration-Specific Information
- Summary of HP Enhancements to GDB
- HP-UX dependencies
  - Linker Dependencies
  - Dependent Standard Library Routines for Run Time Checking
- Supported Platforms and Modes
- HP-UX targets
- Support for Alternate root
- Specifying object file directories
- Fix and continue debugging
  - Fix and Continue compiler dependencies
  - Fix and Continue restrictions
  - Using Fix and Continue
  - Example Fix and Continue session
- Inline Support
  - Inline Debugging in HP 9000 Systems
  - Inline Debugging in Integrity Systems
    - Debugging Inline Functions in Integrity Systems
- Debugging Macros
  - Viewing and Evaluating Macro Definitions
    - Compiler Options to Enable Macro Debugging
  - Examples for Macro Debugging
- Debugging Memory Problems
  - When to suspect a memory leak
  - Memory debugging restrictions
  - Memory Debugging Methodologies
  - Debugging Memory in Interactive Mode
    - Commands for interactive memory debugging
    - Example for interactive debugging session
  - Debugging Memory in Batch Mode
  - Debugging Memory Interactively After Attaching to a Running Process
  - Configuring memory debugging settings
  - Scenarios in memory debugging
  - Comparison of Memory Debugging Commands in Interactive Mode and Batch Mode
  - Heap Profiling
  - Memory Checking Analysis for User Defined Memory Management Routines
  - Commands to track the change in data segment value
- Thread Debugging Support
  - Support for Enabling and Disabling Specific Threads
  - Backtrace Support for Thread Debugging
  - Advanced Thread Debugging Support
  - Debugging Threads Interactively After Attaching to a Process
  - Thread Debugging in Batch Mode
    - Pre-requisites for Batch mode of Thread Debugging
    - Limitations in Batch mode of thread debugging
  - Known issues with Thread Debugging for Interactive and Batch mode
- Debugging MPI Programs
- Debugging multiple processes ( programs with fork and vfork calls)
  - Ask mode for set follow-fork-mode
  - serial mode for set follow-fork-mode
  - Support for showing unwind info
  - Printing CFM and PFS registers
- Debugging Core Files
  - Generating core files with packcore /unpackcore/getcore
  - Support for the dumpcore command
    - Enhancements to the dumpcore command
  - Support for display of run time type information
- Printing the Execution Path Entries for the Current Frame or Thread
  - Compiler Dependencies for Printing the Execution Path Entries
  - Example Illustrating Execution Path Recovery
- Invoking GDB Before a Program Aborts
- Aborting a Command Line Call
- Instruction Level Stepping
- Enhanced support for watchpoints and breakpoints
  - Deferred watchpoints
  - Hardware watchpoints
  - Hardware breakpoints
    - Setting breakpoints in unstripped shared library
  - Support for procedural breakpoints
  - Support for template breakpoints
- Debugging support for shared libraries
  - Using shared library as main program
  - Setting Deferred Breakpoints in Shared Library
  - Using catch load
  - Privately mapping shared libraries
  - Selectively Mapping Shared Libraries As Private
  - Setting breakpoints in shared library
- Language support
  - Enhanced Java Debugging Support
  - Commands for Examining Java Virtual Machine(JVM) internals
    - Java subcommands
  - Support for stack traces in Java, C, and C++ programs
  - Support for 64-bit Java, C, aC++ stack unwinding
  - Enhanced support for C++ templates
  - Support for __fpreg data type on IPF
  - Support for _Complex variables in HP C
  - Support for debugging namespaces
  - Command for evaluating the address of an expression
- Viewing Wide Character Strings
- Support for output logging
  - Support for dumping array in an ASCII file
  - Support for Fortran array slices
  - Displaying enumerators
  - Support for debugging typedefs
  - Support for steplast command for C and C++
- Getting information from a non-debug executable
- Debugging optimized code
  - Debugging Optimized Code at Various Optimization Levels
    - +O0 and +O1
    - +O2/+O3/+O4/-ipo
- Visual Interface for WDB
  - Starting and stopping Visual Interface for WDB
  - Navigating the Visual Interface for WDB display
  - Specifying foreground and background colors
  - Using the X-window graphical interface
  - Using the TUI mode
  - Changing the size of the source or debugger pane
  - Using commands to browse through source files
  - Loading source files
  - Editing source files
  - Editing the command line and command-line history
  - Saving the contents of a debugging session to a file
- Support for ddd
- Support for XDB commands
  - stop in/at dbx commands
- GNU GDB Logging Commands
- Support for command line calls in a stripped executable
  - Support for command line calls in a stripped executable on PA-RISC systems
  - Additional support for command line calls in a stripped executable
    - For 32-bit applications:
    - For 64-bit applications
  - Support for debugging stripped binaries
- Displaying the current block scope information
- Linux support
The HP-UX Terminal User Interface
- Starting the TUI
- Automatically running a program at startup
- Screen Layouts
- Cycling through the panes
- Changing pane focus
- Scrolling panes
- Changing the register display
- Changing the pane size
- Refreshing and updating the window
XDB to WDB Transition Guide
- By-function lists of XDB commands and HP WDB equivalents
- Overall breakpoint commands
- XDB data formats and HP WDB equivalents
- XDB location syntax and HP WDB equivalents
- XDB special language operators and HP WDB equivalents
- XDB special variables and HP WDB equivalents
- XDB variable identifiers and HP WDB equivalents
- Alphabetical lists of XDB commands and HP WDB equivalents
Controlling GDB
- Setting the GDB Prompt
- Setting Command Editing Options in GDB
- Setting Command History Feature in GDB
- Setting the GDB Screen Size
- Supported Number Formats
- Optional warnings and messages
- Optional messages about internal happenings
Canned Sequences of Commands
- User-defined commands
- User-defined command hooks
- Command files
- Commands for controlled output
Using GDB under gnu Emacs
GDB Annotations
- What is an annotation?
- The server prefix
- Values
- Frames
- Displays
- Annotation for GDB input
- Errors
- Information on breakpoints
- Invalidation notices
- Running the program
- Displaying source
- Annotations We Might Want in the Future
The gdb/mi Interface
- Function and purpose
- Notation and terminology
- gdb/mi Command Syntax
- gdb/mi compatibility with CLI
- gdb/mi output records
- gdb/mi command description format
- gdb/mi breakpoint table commands
- gdb/mi Data manipulation
- gdb/mi program control
- Miscellaneous GDB commands in gdb/mi
- gdb/mi Stack Manipulation Commands
- gdb/mi Symbol query commands
- gdb/mi Target Manipulation Commands
- gdb/mi thread commands
- gdb/mi tracepoint commands
- gdb/mi variable objects
Reporting Bugs in GDB
- Have you found a bug?
- How to report bugs
Installing GDB
- Compiling GDB in another directory
- Specifying names for hosts and targets
- configure options
Index

162 Debugging with GDB

14.11.5.1 Pre-requisites for Batch mode of Thread Debugging

The various prerequisites for Batch mode of Thread Debugging are as follows:

- The thread-debugging feature in HP WDB is dependent on the availability of the

dynamic linker version B.11.19.

- Advanced thread-debugging feature requires the pthread tracer library which is

available by default on systems running HP-UX 11i v2 or later.

Steps to debug threads in batch mode

1. Compile the source ﬁles.

- Set the LD_LIBRARY_PATH environment variable, based on the platform as

follows:

- For IPF 32 bit applications, set

LD_LIBRARY_PATH=/opt/langtools/wdb/lib/hpux32

- For IPF 64 bit applications, set

LD_LIBRARY_PATH=/opt/langtools/wdb/lib/hpux64

- For PA 64 bit applications, set

LD_LIBRARY_PATH=/opt/langtools/wdb/lib/pa20_64

2. Map the share libraries as private for HP 9000 systems using the following com-

mand:

$ chatr +dbg enable ./<executable>

Note: This step is not applicable for Integrity systems.

3. Create a conﬁguration ﬁle, rtcconfig to specify the various thread conditions that

you want the debugger to detect.

Note: The conﬁguration ﬁle contains lines of the following form:

set thread-check [on|off] | [option] [on|off] | [option] [num]

And/Or

set frame-count [num]

And/Or

files=<name of the executable on which the thread checking is to be

done>

For more information, Section 14.11.3.2 [Enabling and Disabling Advanced Thread

Debugging Features], page 157

4. Set the environment variable BATCH_RTC to on as: Set BATCH_RTC=on

5. Preload the librtc runtime library explicitly and start the target application using

one of the following commands:

- For 32 bit IPF applications,

LD_PRELOAD=/opt/langtools/lib/hpux32/librtc.so <executable>

- For 64 bit IPF applications,

LD_PRELOAD=/opt/langtools/lib/hpux64/librtc.so <executable>

- For 64 bit PA applications,

LD_PRELOAD=/opt/langtools/lib/pa20_64/librtc.sl <executable>