Debugging with GDB (February 2008)
Table Of Contents
- Summary of GDB
- A Sample GDB Session
- Getting In and Out of GDB
- GDB Commands
- Running Programs Under GDB
- Stopping and Continuing
- Examining the Stack
- Examining Source Files
- Examining Data
- Using GDB with Different Languages
- Examining the Symbol Table
- Altering Execution
- GDB Files
- Specifying a Debugging Target
- HP-UX Configuration-Specific Information
- Summary of HP Enhancements to GDB
- HP-UX dependencies
- Supported Platforms and Modes
- HP-UX targets
- Support for Alternate root
- Specifying object file directories
- Fix and continue debugging
- Inline Support
- Debugging Macros
- Debugging Memory Problems
- When to suspect a memory leak
- Memory debugging restrictions
- Memory Debugging Methodologies
- Debugging Memory in Interactive Mode
- Debugging Memory in Batch Mode
- Debugging Memory Interactively After Attaching to a Running Process
- Configuring memory debugging settings
- Scenarios in memory debugging
- Stop when freeing unallocated or deallocated blocks
- Stop when freeing a block if bad writes occurred outside block boundary
- Stop when a specified block address is allocated or deallocated
- Scramble previous memory contents at malloc/free calls
- Detect dangling pointers and dangling blocks
- Detect in-block corruption of freed blocks
- Specify the amount of guard bytes for every block of allocated memory
- 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
- Debugging MPI Programs
- Debugging multiple processes ( programs with fork and vfork calls)
- Debugging Core Files
- Printing the Execution Path Entries for the Current Frame or Thread
- Invoking GDB Before a Program Aborts
- Aborting a Command Line Call
- Instruction Level Stepping
- Enhanced support for watchpoints and breakpoints
- Debugging support for shared libraries
- Language support
- Enhanced Java Debugging Support
- Commands for Examining Java Virtual Machine(JVM) internals
- 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
- Getting information from a non-debug executable
- Debugging optimized code
- 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
- GNU GDB Logging Commands
- Support for command line calls in a stripped executable
- Displaying the current block scope information
- Linux support
- The HP-UX Terminal User Interface
- 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
- Canned Sequences of Commands
- Using GDB under gnu Emacs
- GDB Annotations
- 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
- Installing GDB
- Index
118 Debugging with GDB
• Support for debugging large core files (> 2GB)
HP WDB supports debugging of core files with sizes more than 2 GB.
• Support co-variant type
HP WDB can step into a co-variant function. The compiler-generated function called
thunks, which is used internally by the compiler to support co-variant return type,
is not shown when you do a backtrace or switch from one frame to another frame.
Similarly, using a finish or return command at a co-variant callee function directly
returns the control back to the caller of thunks.
• New attach command line options and handling (-pid or -p)
HP WDB accepts -pid or -p followed by a process ID to attach a running process to
the debugger.
Note:
HP WDB cannot be attached to a process that is traced by tools which
use ttrace, such as Caliper, adb, and tusc. The debugger displays the
following error message on attempting to attach to such a process:
Attaching to process <pid> failed.
Hint: Check if this process is already being traced by another gdb or
other ttrace tools like caliper and tusc.
Hint: Check whether program is on an NFS-mounted file-system.
If so, you will need to mount the file system with the "nointr" option
with mount(1) or make a local copy of the program to resolve this problem.
14.4 HP-UX targets
On HP-UX systems, GDB has been configured to support debugging of processes running
on the PA-RISC and Itanium architectures. This means that the only possible targets are:
• An executable that has been compiled and linked to run on HP-UX. This includes
binaries that have been marked as SHMEM_MAGIC.
• A live HP-UX process, either started by WDB (with the run command) or started
outside of WDB and attached to (with the attach command).
• A core file generated by an HP-UX process that previously aborted execution.
GDB on HP-UX has not been configured to support remote debugging, or to support
programs running on other platforms.
WDB can only debug C++ programs compiled with HP aC++, the ANSI-compatible C++
compiler.
14.5 Support for Alternate root
HP WDB supports alternate root functionality, which is helpful when you do not want
to use the system-installed HP WDB or its components.
The environment variable WDB_ROOT specifies the alternate root for HP WDB. You must
specify a structure similar to the default /opt/langtools used for HP WDB. You can use
the environment variable GDB_ROOT to specify an alternate root for GDB.