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Text File | 1992-04-10 | 18.5 KB | 501 lines

What has changed since GDB-3.5? (Organized release by release) *** Changes in GDB-4.5: * New machines supported (host and target) IBM RS6000 running AIX rs6000-ibm-aix or rs6000 SGI Irix-4.x mips-sgi-irix4 or iris4 * New malloc package GDB now uses a new memory manager called mmalloc, based on gmalloc. Mmalloc is capable of handling mutiple heaps of memory. It is also capable of saving a heap to a file, and then mapping it back in later. This can be used to greatly speedup the startup of GDB by using a pre-parsed symbol table which lives in a mmalloc managed heap. For more details, please read mmalloc/mmalloc.texi. * info proc The 'info proc' command (SVR4 only) has been enhanced quite a bit. See 'help info proc' for details. * MIPS ecoff symbol table format The code that reads MIPS symbol table format is now supported on all hosts. Thanks to MIPS for releasing the sym.h and symconst.h files to make this possible. * File name changes for MS-DOS Many files in the config directories have been renamed to make it easier to support GDB on MS-DOSe systems (which have very restrictive file name conventions :-( ). MS-DOSe host support (under DJ Delorie's GO32 environment) is close to working but has some remaining problems. Note that debugging of DOS programs is not supported, due to limitations in the ``operating system'', but it can be used to host cross-debugging. * Cross byte order fixes Many fixes have been made to support cross debugging of Sparc and MIPS targets from hosts whose byte order differs. * New -mapped and -readnow options If memory-mapped files are available on your system through the 'mmap' system call, you can use the -mapped option on the `file' or `symbol-file' commands to cause GDB to write the symbols from your program into a reusable file. If the program you are debugging is called `/tmp/fred', the mapped symbol file will be `/tmp/fred.syms'. Future GDB debugging sessions will notice the presence of this file, and will quickly map in symbol information from it, rather than reading the symbol table from the executable program. Using the '-mapped' option in a GDB `file' or `symbol-file' command has the same effect as starting GDB with the '-mapped' command-line option. You can cause GDB to read the entire symbol table immediately by using the '-readnow' option with any of the commands that load symbol table information (or on the GDB command line). This makes the command slower, but makes future operations faster. The -mapped and -readnow options are typically combined in order to build a `fred.syms' file that contains complete symbol information. A simple GDB invocation to do nothing but build a `.syms' file for future use is: gdb -batch -nx -mapped -readnow programname The `.syms' file is specific to the host machine on which GDB is run. It holds an exact image of GDB's internal symbol table. It cannot be shared across multiple host platforms. * longjmp() handling GDB is now capable of stepping and nexting over longjmp(), _longjmp(), and siglongjmp() without losing control. This feature has not yet been ported to all systems. It currently works on many 386 platforms, all MIPS-based platforms (SGI, DECstation, etc), and Sun3/4. * Solaris 2.0 Preliminary work has been put in to support the new Solaris OS from Sun. At this time, it can control and debug processes, but it is not capable of reading symbols. * Bug fixes As always, many many bug fixes. The major areas were with g++, and mipsread. People using the MIPS-based platforms should experience fewer mysterious crashes and trashed symbol tables. *** Changes in GDB-4.4: * New machines supported (host and target) SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco (except core files) BSD Reno on Vax vax-dec-bsd Ultrix on Vax vax-dec-ultrix * New machines supported (target) AMD 29000 embedded, using EBMON a29k-none-none * C++ support GDB continues to improve its handling of C++. `References' work better. The demangler has also been improved, and now deals with symbols mangled as per the Annotated C++ Reference Guide. GDB also now handles `stabs' symbol information embedded in MIPS `ecoff' symbol tables. Since the ecoff format was not easily extensible to handle new languages such as C++, this appeared to be a good way to put C++ debugging info into MIPS binaries. This option will be supported in the GNU C compiler, version 2, when it is released. * New features for SVR4 GDB now handles SVR4 shared libraries, in the same fashion as SunOS shared libraries. Debugging dynamically linked programs should present only minor differences from debugging statically linked programs. The `info proc' command will print out information about any process on an SVR4 system (including the one you are debugging). At the moment, it prints the address mappings of the process. If you bring up GDB on another SVR4 system, please send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were reqired (if any). * Better dynamic linking support in SunOS Reading symbols from shared libraries which contain debugging symbols now works properly. However, there remain issues such as automatic skipping of `transfer vector' code during function calls, which make it harder to debug code in a shared library, than to debug the same code linked statically. * New Getopt GDB is now using the latest `getopt' routines from the FSF. This version accepts the -- prefix for options with long names. GDB will continue to accept the old forms (-option and +option) as well. Various single letter abbreviations for options have been explicity added to the option table so that they won't get overshadowed in the future by other options that begin with the same letter. * Bugs fixed The `cleanup_undefined_types' bug that many of you noticed has been squashed. Many assorted bugs have been handled. Many more remain to be handled. See the various ChangeLog files (primarily in gdb and bfd) for details. *** Changes in GDB-4.3: * New machines supported (host and target) Amiga 3000 running Amix m68k-cbm-svr4 or amix NCR 3000 386 running SVR4 i386-ncr-svr4 or ncr3000 Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88 * Almost SCO Unix support We had hoped to support: SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco (except for core file support), but we discovered very late in the release that it has problems with process groups that render gdb unusable. Sorry about that. I encourage people to fix it and post the fixes. * Preliminary ELF and DWARF support GDB can read ELF object files on System V Release 4, and can handle debugging records for C, in DWARF format, in ELF files. This support is preliminary. If you bring up GDB on another SVR4 system, please send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were reqired (if any). * New Readline GDB now uses the latest `readline' library. One user-visible change is that two tabs will list possible command completions, which previously required typing M-? (meta-question mark, or ESC ?). * Bugs fixed The `stepi' bug that many of you noticed has been squashed. Many bugs in C++ have been handled. Many more remain to be handled. See the various ChangeLog files (primarily in gdb and bfd) for details. * State of the MIPS world (in case you wondered): GDB can understand the symbol tables emitted by the compilers supplied by most vendors of MIPS-based machines, including DEC. These symbol tables are in a format that essentially nobody else uses. Some versions of gcc come with an assembler post-processor called mips-tfile. This program is required if you want to do source-level debugging of gcc-compiled programs. I believe FSF does not ship mips-tfile with gcc version 1, but it will eventually come with gcc version 2. Debugging of g++ output remains a problem. g++ version 1.xx does not really support it at all. (If you're lucky, you should be able to get line numbers and stack traces to work, but no parameters or local variables.) With some work it should be possible to improve the situation somewhat. When gcc version 2 is released, you will have somewhat better luck. However, even then you will get confusing results for inheritance and methods. We will eventually provide full debugging of g++ output on DECstations. This will probably involve some kind of stabs-in-ecoff encapulation, but the details have not been worked out yet. *** Changes in GDB-4.2: * Improved configuration Only one copy of `configure' exists now, and it is not self-modifying. Porting BFD is simpler. * Stepping improved The `step' and `next' commands now only stop at the first instruction of a source line. This prevents the multiple stops that used to occur in switch statements, for-loops, etc. `Step' continues to stop if a function that has debugging information is called within the line. * Bug fixing Lots of small bugs fixed. More remain. * New host supported (not target) Intel 386 PC clone running Mach i386-none-mach *** Changes in GDB-4.1: * Multiple source language support GDB now has internal scaffolding to handle several source languages. It determines the type of each source file from its filename extension, and will switch expression parsing and number formatting to match the language of the function in the currently selected stack frame. You can also specifically set the language to be used, with `set language c' or `set language modula-2'. * GDB and Modula-2 GDB now has preliminary support for the GNU Modula-2 compiler, currently under development at the State University of New York at Buffalo. Development of both GDB and the GNU Modula-2 compiler will continue through the fall of 1991 and into 1992. Other Modula-2 compilers are currently not supported, and attempting to debug programs compiled with them will likely result in an error as the symbol table is read. Feel free to work on it, though! There are hooks in GDB for strict type checking and range checking, in the `Modula-2 philosophy', but they do not currently work. * set write on/off GDB can now write to executable and core files (e.g. patch a variable's value). You must turn this switch on, specify the file ("exec foo" or "core foo"), *then* modify it, e.g. by assigning a new value to a variable. Modifications take effect immediately. * Automatic SunOS shared library reading When you run your program, GDB automatically determines where its shared libraries (if any) have been loaded, and reads their symbols. The `share' command is no longer needed. This also works when examining core files. * set listsize You can specify the number of lines that the `list' command shows. The default is 10. * New machines supported (host and target) SGI Iris (MIPS) running Irix V3: mips-sgi-irix or iris Sony NEWS (68K) running NEWSOS 3.x: m68k-sony-sysv or news Ultracomputer (29K) running Sym1: a29k-nyu-sym1 or ultra3 * New hosts supported (not targets) IBM RT/PC: romp-ibm-aix or rtpc * New targets supported (not hosts) AMD 29000 embedded with COFF a29k-none-coff AMD 29000 embedded with a.out a29k-none-aout Ultracomputer remote kernel debug a29k-nyu-kern * New remote interfaces AMD 29000 Adapt AMD 29000 Minimon *** Changes in GDB-4.0: * New Facilities Wide output is wrapped at good places to make the output more readable. Gdb now supports cross-debugging from a host machine of one type to a target machine of another type. Communication with the target system is over serial lines. The ``target'' command handles connecting to the remote system; the ``load'' command will download a program into the remote system. Serial stubs for the m68k and i386 are provided. Gdb also supports debugging of realtime processes running under VxWorks, using SunRPC Remote Procedure Calls over TCP/IP to talk to a debugger stub on the target system. New CPUs supported include the AMD 29000 and Intel 960. GDB now reads object files and symbol tables via a ``binary file'' library, which allows a single copy of GDB to debug programs of multiple object file types such as a.out and coff. There is now a GDB reference card in "doc/refcard.tex". (Make targets refcard.dvi and refcard.ps are available to format it). * Control-Variable user interface simplified All variables that control the operation of the debugger can be set by the ``set'' command, and displayed by the ``show'' command. For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>. ``Show prompt'' produces the response: Gdb's prompt is new-gdb=>. What follows are the NEW set commands. The command ``help set'' will print a complete list of old and new set commands. ``help set FOO'' will give a longer description of the variable FOO. ``show'' will show all of the variable descriptions and their current settings. confirm on/off: Enables warning questions for operations that are hard to recover from, e.g. rerunning the program while it is already running. Default is ON. editing on/off: Enables EMACS style command line editing of input. Previous lines can be recalled with control-P, the current line can be edited with control-B, you can search for commands with control-R, etc. Default is ON. history filename NAME: NAME is where the gdb command history will be stored. The default is .gdb_history, or the value of the environment variable GDBHISTFILE. history size N: The size, in commands, of the command history. The default is 256, or the value of the environment variable HISTSIZE. history save on/off: If this value is set to ON, the history file will be saved after exiting gdb. If set to OFF, the file will not be saved. The default is OFF. history expansion on/off: If this value is set to ON, then csh-like history expansion will be performed on command line input. The default is OFF. radix N: Sets the default radix for input and output. It can be set to 8, 10, or 16. Note that the argument to "radix" is interpreted in the current radix, so "set radix 10" is always a no-op. height N: This integer value is the number of lines on a page. Default is 24, the current `stty rows'' setting, or the ``li#'' setting from the termcap entry matching the environment variable TERM. width N: This integer value is the number of characters on a line. Default is 80, the current `stty cols'' setting, or the ``co#'' setting from the termcap entry matching the environment variable TERM. Note: ``set screensize'' is obsolete. Use ``set height'' and ``set width'' instead. print address on/off: Print memory addresses in various command displays, such as stack traces and structure values. Gdb looks more ``symbolic'' if you turn this off; it looks more ``machine level'' with it on. Default is ON. print array on/off: Prettyprint arrays. New convenient format! Default is OFF. print demangle on/off: Print C++ symbols in "source" form if on, "raw" form if off. print asm-demangle on/off: Same, for assembler level printouts like instructions. print vtbl on/off: Prettyprint C++ virtual function tables. Default is OFF. * Support for Epoch Environment. The epoch environment is a version of Emacs v18 with windowing. One new command, ``inspect'', is identical to ``print'', except that if you are running in the epoch environment, the value is printed in its own window. * Support for Shared Libraries GDB can now debug programs and core files that use SunOS shared libraries. Symbols from a shared library cannot be referenced before the shared library has been linked with the program (this happens after you type ``run'' and before the function main() is entered). At any time after this linking (including when examining core files from dynamically linked programs), gdb reads the symbols from each shared library when you type the ``sharedlibrary'' command. It can be abbreviated ``share''. sharedlibrary REGEXP: Load shared object library symbols for files matching a unix regular expression. No argument indicates to load symbols for all shared libraries. info sharedlibrary: Status of loaded shared libraries. * Watchpoints A watchpoint stops execution of a program whenever the value of an expression changes. Checking for this slows down execution tremendously whenever you are in the scope of the expression, but is quite useful for catching tough ``bit-spreader'' or pointer misuse problems. Some machines such as the 386 have hardware for doing this more quickly, and future versions of gdb will use this hardware. watch EXP: Set a watchpoint (breakpoint) for an expression. info watchpoints: Information about your watchpoints. delete N: Deletes watchpoint number N (same as breakpoints). disable N: Temporarily turns off watchpoint number N (same as breakpoints). enable N: Re-enables watchpoint number N (same as breakpoints). * C++ multiple inheritance When used with a GCC version 2 compiler, GDB supports multiple inheritance for C++ programs. * C++ exception handling Gdb now supports limited C++ exception handling. Besides the existing ability to breakpoint on an exception handler, gdb can breakpoint on the raising of an exception (before the stack is peeled back to the handler's context). catch FOO: If there is a FOO exception handler in the dynamic scope, set a breakpoint to catch exceptions which may be raised there. Multiple exceptions (``catch foo bar baz'') may be caught. info catch: Lists all exceptions which may be caught in the current stack frame. * Minor command changes The command ``call func (arg, arg, ...)'' now acts like the print command, except it does not print or save a value if the function's result is void. This is similar to dbx usage. The ``up'' and ``down'' commands now always print the frame they end up at; ``up-silently'' and `down-silently'' can be used in scripts to change frames without printing. * New directory command 'dir' now adds directories to the FRONT of the source search path. The path starts off empty. Source files that contain debug information about the directory in which they were compiled can be found even with an empty path; Sun CC and GCC include this information. If GDB can't find your source file in the current directory, type "dir .". * Configuring GDB for compilation For normal use, type ``./configure host''. See README or gdb.texinfo for more details. GDB now handles cross debugging. If you are remotely debugging between two different machines, type ``./configure host -target=targ''. Host is the machine where GDB will run; targ is the machine where the program that you are debugging will run.