gdb/PROBLEMS

   1
   2                         Known problems in GDB 6.2
   3
   4                 See also: http://www.gnu.org/software/gdb/bugs/
   5
   6
   7 *** Build problems
   8
   9 build/1458: compile failed on hpux11
  10
  11 GDB has build problems on HP/UX 11 with some versions of the HP
  12 Ansi C compiler.  (GCC works fine).
  13
  14 The problem happens when compiling intl/bindtextdom.c.
  15 The error is:
  16
  17   cc: "gettextP.h", line 50: error 1000: Unexpected symbol: "SWAP".
  18   cc: panic 2017: Cannot recover from earlier errors, terminating.
  19   *** Error exit code 1
  20
  21 This is a problem with the 'inline' keyword in gettextP.h.
  22 The workaround is to disable 'inline' before building gdb:
  23
  24   export ac_cv_c_inline=no
  25
  26 This problem happens only with some versions of the HP Ansi C compiler.
  27 Versions A.11.01.25171.GP and B.11.11.28706.GP have both been observed
  28 to work; version B.11.11.04 gets the build error and needs the
  29 workaround.
  30
  31 This problem might also happen with other C compilers.
  32
  33 *** Misc
  34
  35 gdb/1560: Control-C does not always interrupt GDB.
  36
  37 When GDB is busy processing a command which takes a long time to
  38 complete, hitting Control-C does not have the expected effect.
  39 The command execution is not aborted, and the "QUIT" message confirming
  40 the abortion is displayed only after the command has been completed.
  41
  42 *** C++ support
  43
  44 gdb/931: GDB could be more generous when reading types C++ templates on input
  45
  46 When the user types a template, GDB frequently requires the type to be
  47 typed in a certain way (e.g. "const char*" as opposed to "const char *"
  48 or "char const *" or "char const*").
  49
  50 gdb/1512: no canonical way to output names of C++ types
  51
  52 We currently don't have any canonical way to output names of C++ types.
  53 E.g. "const char *" versus "char const *"; more subtleties arise when
  54 dealing with templates.
  55
  56 gdb/1516: [regression] local classes, gcc 2.95.3, dwarf-2
  57
  58 With gcc 2.95.3 and the dwarf-2 debugging format, classes which are
  59 defined locally to a function include the demangled name of the function
  60 as part of their name.  For example, if a function "foobar" contains a
  61 local class definition "Local", gdb will say that the name of the class
  62 type is "foobar__Fi.0:Local".
  63
  64 This applies only to classes where the class type is defined inside a
  65 function, not to variables defined with types that are defined somewhere
  66 outside any function (which most types are).
  67
  68 gdb/1588: names of c++ nested types in casts must be enclosed in quotes
  69
  70 You must type
  71   (gdb) print ('Foo::Bar') x
  72 or
  73   (gdb) print ('Foo::Bar' *) y
  74 instead of
  75   (gdb) print (Foo::Bar) x
  76 or
  77   (gdb) print (Foo::Bar *) y
  78 respectively.
  79
  80 gdb/1091: Constructor breakpoints ignored
  81 gdb/1193: g++ 3.3 creates multiple constructors: gdb 5.3 can't set breakpoints
  82
  83 When gcc 3.x compiles a C++ constructor or C++ destructor, it generates
  84 2 or 3 different versions of the object code.  These versions have
  85 unique mangled names (they have to, in order for linking to work), but
  86 they have identical source code names, which leads to a great deal of
  87 confusion.  Specifically, if you set a breakpoint in a constructor or a
  88 destructor, gdb will put a breakpoint in one of the versions, but your
  89 program may execute the other version.  This makes it impossible to set
  90 breakpoints reliably in constructors or destructors.
  91
  92 gcc 3.x generates these multiple object code functions in order to
  93 implement virtual base classes.  gcc 2.x generated just one object code
  94 function with a hidden parameter, but gcc 3.x conforms to a multi-vendor
  95 ABI for C++ which requires multiple object code functions.
  96
  97 *** Stack backtraces
  98
  99 GDB's core code base has been updated to use a new backtrace
 100 mechanism.  This mechanism makes it possible to support new features
 101 such DWARF 2 Call Frame Information (which in turn makes possible
 102 backtraces through optimized code).
 103
 104 Since this code is new, it is known to still have a few problems:
 105
 106 gdb/1505: [regression] gdb prints a bad backtrace for a thread
 107
 108 When backtracing a thread, gdb does not stop when it reaches the
 109 outermost frame, instead continuing until it hits garbage.  This is
 110 sensitive to the operating system and thread library.
 111
 112 hppa*-*-*
 113 mips*-*-*
 114
 115 The MIPS and HPPA backtrace code has only very recently been updated
 116 to use GDB's new frame mechanism.  At present there are still a few
 117 problems, in particular backtraces through signal handlers do not
 118 work.
 119
 120 People encountering problems with these architectures should consult
 121 GDB's web pages and mailing lists (http://www.gnu.org/software/gdb/)
 122 to see if there are updates.
 123
 124 powerpc*-*-*
 125
 126 PowerPC architecture support, in 6.1, does not use the new frame code.
 127
 128 Fortunately, PowerPC architecture support, in GDB's mainline sources,
 129 have been updated.  People encountering problems should consider
 130 downloading a more current snapshot of GDB
 131 (http://www.gnu.org/software/gdb/current/).