proceed until the function returns.
An argument is a repeat count, as in @code{next}.
+
+@end table
+
+@anchor{range stepping}
+@cindex range stepping
+@cindex target-assisted range stepping
+By default, and if available, @value{GDBN} makes use of
+target-assisted @dfn{range stepping}. In other words, whenever you
+use a stepping command (e.g., @code{step}, @code{next}), @value{GDBN}
+tells the target to step the corresponding range of instruction
+addresses instead of issuing multiple single-steps. This speeds up
+line stepping, particularly for remote targets. Ideally, there should
+be no reason you would want to turn range stepping off. However, it's
+possible that a bug in the debug info, a bug in the remote stub (for
+remote targets), or even a bug in @value{GDBN} could make line
+stepping behave incorrectly when target-assisted range stepping is
+enabled. You can use the following command to turn off range stepping
+if necessary:
+
+@table @code
+@kindex set range-stepping
+@kindex show range-stepping
+@item set range-stepping
+@itemx show range-stepping
+Control whether range stepping is enabled.
+
+If @code{on}, and the target supports it, @value{GDBN} tells the
+target to step a range of addresses itself, instead of issuing
+multiple single-steps. If @code{off}, @value{GDBN} always issues
+single-steps, even if range stepping is supported by the target. The
+default is @code{on}.
+
@end table
@node Skipping Over Functions and Files
strings. Single-byte members of a vector are displayed as an integer
array.
+@item z
+Like @samp{x} formatting, the value is treated as an integer and
+printed as hexadecimal, but leading zeros are printed to pad the value
+to the size of the integer type.
+
@item r
@cindex raw printing
Print using the @samp{raw} formatting. By default, @value{GDBN} will
@item show print frame-arguments
Show how the value of arguments should be displayed when printing a frame.
+@item set print raw frame-arguments on
+Print frame arguments in raw, non pretty-printed, form.
+
+@item set print raw frame-arguments off
+Print frame arguments in pretty-printed form, if there is a pretty-printer
+for the value (@pxref{Pretty Printing}),
+otherwise print the value in raw form.
+This is the default.
+
+@item show print raw frame-arguments
+Show whether to print frame arguments in raw form.
+
@anchor{set print entry-values}
@item set print entry-values @var{value}
@kindex set print entry-values
however, a convenience function is implemented internally to
@value{GDBN}.
+These functions do not require @value{GDBN} to be configured with
+@code{Python} support, which means that they are always available.
+
+@table @code
+
+@item $_isvoid (@var{expr})
+@findex $_isvoid@r{, convenience function}
+Return one if the expression @var{expr} is @code{void}. Otherwise it
+returns zero.
+
+A @code{void} expression is an expression where the type of the result
+is @code{void}. For example, you can examine a convenience variable
+(see @ref{Convenience Vars,, Convenience Variables}) to check whether
+it is @code{void}:
+
+@smallexample
+(@value{GDBP}) print $_exitcode
+$1 = void
+(@value{GDBP}) print $_isvoid ($_exitcode)
+$2 = 1
+(@value{GDBP}) run
+Starting program: ./a.out
+[Inferior 1 (process 29572) exited normally]
+(@value{GDBP}) print $_exitcode
+$3 = 0
+(@value{GDBP}) print $_isvoid ($_exitcode)
+$4 = 0
+@end smallexample
+
+In the example above, we used @code{$_isvoid} to check whether
+@code{$_exitcode} is @code{void} before and after the execution of the
+program being debugged. Before the execution there is no exit code to
+be examined, therefore @code{$_exitcode} is @code{void}. After the
+execution the program being debugged returned zero, therefore
+@code{$_exitcode} is zero, which means that it is not @code{void}
+anymore.
+
+The @code{void} expression can also be a call of a function from the
+program being debugged. For example, given the following function:
+
+@smallexample
+void
+foo (void)
+@{
+@}
+@end smallexample
+
+The result of calling it inside @value{GDBN} is @code{void}:
+
+@smallexample
+(@value{GDBP}) print foo ()
+$1 = void
+(@value{GDBP}) print $_isvoid (foo ())
+$2 = 1
+(@value{GDBP}) set $v = foo ()
+(@value{GDBP}) print $v
+$3 = void
+(@value{GDBP}) print $_isvoid ($v)
+$4 = 1
+@end smallexample
+
+@end table
+
These functions require @value{GDBN} to be configured with
@code{Python} support.
true contents of hardware registers, you must select the innermost
frame (with @samp{frame 0}).
-However, @value{GDBN} must deduce where registers are saved, from the machine
-code generated by your compiler. If some registers are not saved, or if
-@value{GDBN} is unable to locate the saved registers, the selected stack
-frame makes no difference.
+@cindex caller-saved registers
+@cindex call-clobbered registers
+@cindex volatile registers
+@cindex <not saved> values
+Usually ABIs reserve some registers as not needed to be saved by the
+callee (a.k.a.: ``caller-saved'', ``call-clobbered'' or ``volatile''
+registers). It may therefore not be possible for @value{GDBN} to know
+the value a register had before the call (in other words, in the outer
+frame), if the register value has since been changed by the callee.
+@value{GDBN} tries to deduce where the inner frame saved
+(``callee-saved'') registers, from the debug info, unwind info, or the
+machine code generated by your compiler. If some register is not
+saved, and @value{GDBN} knows the register is ``caller-saved'' (via
+its own knowledge of the ABI, or because the debug/unwind info
+explicitly says the register's value is undefined), @value{GDBN}
+displays @w{@samp{<not saved>}} as the register's value. With targets
+that @value{GDBN} has no knowledge of the register saving convention,
+if a register was not saved by the callee, then its value and location
+in the outer frame are assumed to be the same of the inner frame.
+This is usually harmless, because if the register is call-clobbered,
+the caller either does not care what is in the register after the
+call, or has code to restore the value that it does care about. Note,
+however, that if you change such a register in the outer frame, you
+may also be affecting the inner frame. Also, the more ``outer'' the
+frame is you're looking at, the more likely a call-clobbered
+register's value is to be wrong, in the sense that it doesn't actually
+represent the value the register had just before the call.
@node Floating Point Hardware
@section Floating Point Hardware
There are two encodings in use, depending on the architecture: BID (Binary
Integer Decimal) for x86 and x86-64, and DPD (Densely Packed Decimal) for
-PowerPC. @value{GDBN} will use the appropriate encoding for the configured
-target.
+PowerPC and S/390. @value{GDBN} will use the appropriate encoding for the
+configured target.
Because of a limitation in @file{libdecnumber}, the library used by @value{GDBN}
to manipulate decimal floating point numbers, it is not possible to convert
@cindex symbol dump
@kindex maint print psymbols
@cindex partial symbol dump
+@kindex maint print msymbols
+@cindex minimal symbol dump
@item maint print symbols @var{filename}
@itemx maint print psymbols @var{filename}
@itemx maint print msymbols @var{filename}
@smallexample
# Extract the dynamic symbols from the main binary, there is no need
-# to also have these in the normal symbol table
+# to also have these in the normal symbol table.
nm -D @var{binary} --format=posix --defined-only \
| awk '@{ print $1 @}' | sort > dynsyms
-# Extract all the text (i.e. function) symbols from the debuginfo .
+# Extract all the text (i.e. function) symbols from the debuginfo.
+# (Note that we actually also accept "D" symbols, for the benefit
+# of platforms like PowerPC64 that use function descriptors.)
nm @var{binary} --format=posix --defined-only \
- | awk '@{ if ($2 == "T" || $2 == "t") print $1 @}' \
+ | awk '@{ if ($2 == "T" || $2 == "t" || $2 == "D") print $1 @}' \
| sort > funcsyms
# Keep all the function symbols not already in the dynamic symbol
# table.
comm -13 dynsyms funcsyms > keep_symbols
+# Separate full debug info into debug binary.
+objcopy --only-keep-debug @var{binary} debug
+
# Copy the full debuginfo, keeping only a minimal set of symbols and
# removing some unnecessary sections.
objcopy -S --remove-section .gdb_index --remove-section .comment \
- --keep-symbols=keep_symbols @var{binary} mini_debuginfo
+ --keep-symbols=keep_symbols debug mini_debuginfo
+
+# Drop the full debug info from the original binary.
+strip --strip-all -R .comment @var{binary}
# Inject the compressed data into the .gnu_debugdata section of the
# original binary.
@end table
-Some configurations may include these targets as well:
-
-@table @code
-
-@item target nrom @var{dev}
-@cindex NetROM ROM emulator target
-NetROM ROM emulator. This target only supports downloading.
-
-@end table
-
Different targets are available on different configurations of @value{GDBN};
your configuration may have more or fewer targets.
@cindex @option{--once}, @code{gdbserver} option
By default, @code{gdbserver} keeps the listening TCP port open, so that
-additional connections are possible. However, if you start @code{gdbserver}
+subsequent connections are possible. However, if you start @code{gdbserver}
with the @option{--once} option, it will stop listening for any further
connection attempts after connecting to the first @value{GDBN} session. This
means no further connections to @code{gdbserver} will be possible after the
@item show debug solib-frv
Display the current state of FR-V shared-library code debugging
messages.
+@item set debug symfile
+@cindex symbol file functions
+Turns on or off display of debugging messages related to symbol file functions.
+The default is off. @xref{Files}.
+@item show debug symfile
+Show the current state of symbol file debugging messages.
@item set debug symtab-create
@cindex symbol table creation
Turns on or off display of debugging messages related to symbol table creation.
@subsubheading Synopsis
@smallexample
- -exec-run [--all | --thread-group N]
+ -exec-run [ --all | --thread-group N ] [ --start ]
@end smallexample
Starts execution of the inferior from the beginning. The inferior
exits. In the latter case the output will include an exit code, if
the program has exited exceptionally.
-When no option is specified, the current inferior is started. If the
+When neither the @samp{--all} nor the @samp{--thread-group} option
+is specified, the current inferior is started. If the
@samp{--thread-group} option is specified, it should refer to a thread
group of type @samp{process}, and that thread group will be started.
If the @samp{--all} option is specified, then all inferiors will be started.
+Using the @samp{--start} option instructs the debugger to stop
+the execution at the start of the inferior's main subprogram,
+following the same behavior as the @code{start} command
+(@pxref{Starting}).
+
@subsubheading @value{GDBN} Command
The corresponding @value{GDBN} command is @samp{run}.
@subsubheading Synopsis
@smallexample
- -stack-list-arguments [ --no-frame-filters ] @var{print-values}
+ -stack-list-arguments [ --no-frame-filters ] [ --skip-unavailable ] @var{print-values}
[ @var{low-frame} @var{high-frame} ]
@end smallexample
structures and unions. If the option @code{--no-frame-filters} is
supplied, then Python frame filters will not be executed.
+If the @code{--skip-unavailable} option is specified, arguments that
+are not available are not listed. Partially available arguments
+are still displayed, however.
Use of this command to obtain arguments in a single frame is
deprecated in favor of the @samp{-stack-list-variables} command.
@subsubheading Synopsis
@smallexample
- -stack-list-locals [ --no-frame-filters ] @var{print-values}
+ -stack-list-locals [ --no-frame-filters ] [ --skip-unavailable ] @var{print-values}
@end smallexample
Display the local variable names for the selected frame. If
more detail. If the option @code{--no-frame-filters} is supplied, then
Python frame filters will not be executed.
+If the @code{--skip-unavailable} option is specified, local variables
+that are not available are not listed. Partially available local
+variables are still displayed, however.
+
This command is deprecated in favor of the
@samp{-stack-list-variables} command.
@subsubheading Synopsis
@smallexample
- -stack-list-variables [ --no-frame-filters ] @var{print-values}
+ -stack-list-variables [ --no-frame-filters ] [ --skip-unavailable ] @var{print-values}
@end smallexample
Display the names of local variables and function arguments for the selected frame. If
structures and unions. If the option @code{--no-frame-filters} is
supplied, then Python frame filters will not be executed.
+If the @code{--skip-unavailable} option is specified, local variables
+and arguments that are not available are not listed. Partially
+available arguments and local variables are still displayed, however.
+
@subsubheading Example
@smallexample
@subsubheading Synopsis
@smallexample
- -data-list-register-values @var{fmt} [ ( @var{regno} )*]
+ -data-list-register-values
+ [ @code{--skip-unavailable} ] @var{fmt} [ ( @var{regno} )*]
@end smallexample
Display the registers' contents. @var{fmt} is the format according to
which the registers' contents are to be returned, followed by an optional
list of numbers specifying the registers to display. A missing list of
-numbers indicates that the contents of all the registers must be returned.
+numbers indicates that the contents of all the registers must be
+returned. The @code{--skip-unavailable} option indicates that only
+the available registers are to be returned.
Allowed formats for @var{fmt} are:
The corresponding @value{GDBN} command is @samp{tvariable}.
+@subheading The @code{-trace-frame-collected} Command
+@findex -trace-frame-collected
+
+@subsubheading Synopsis
+
+@smallexample
+ -trace-frame-collected
+ [--var-print-values @var{var_pval}]
+ [--comp-print-values @var{comp_pval}]
+ [--registers-format @var{regformat}]
+ [--memory-contents]
+@end smallexample
+
+This command returns the set of collected objects, register names,
+trace state variable names, memory ranges and computed expressions
+that have been collected at a particular trace frame. The optional
+parameters to the command affect the output format in different ways.
+See the output description table below for more details.
+
+The reported names can be used in the normal manner to create
+varobjs and inspect the objects themselves. The items returned by
+this command are categorized so that it is clear which is a variable,
+which is a register, which is a trace state variable, which is a
+memory range and which is a computed expression.
+
+For instance, if the actions were
+@smallexample
+collect myVar, myArray[myIndex], myObj.field, myPtr->field, myCount + 2
+collect *(int*)0xaf02bef0@@40
+@end smallexample
+
+@noindent
+the object collected in its entirety would be @code{myVar}. The
+object @code{myArray} would be partially collected, because only the
+element at index @code{myIndex} would be collected. The remaining
+objects would be computed expressions.
+
+An example output would be:
+
+@smallexample
+(gdb)
+-trace-frame-collected
+^done,
+ explicit-variables=[@{name="myVar",value="1"@}],
+ computed-expressions=[@{name="myArray[myIndex]",value="0"@},
+ @{name="myObj.field",value="0"@},
+ @{name="myPtr->field",value="1"@},
+ @{name="myCount + 2",value="3"@},
+ @{name="$tvar1 + 1",value="43970027"@}],
+ registers=[@{number="0",value="0x7fe2c6e79ec8"@},
+ @{number="1",value="0x0"@},
+ @{number="2",value="0x4"@},
+ ...
+ @{number="125",value="0x0"@}],
+ tvars=[@{name="$tvar1",current="43970026"@}],
+ memory=[@{address="0x0000000000602264",length="4"@},
+ @{address="0x0000000000615bc0",length="4"@}]
+(gdb)
+@end smallexample
+
+Where:
+
+@table @code
+@item explicit-variables
+The set of objects that have been collected in their entirety (as
+opposed to collecting just a few elements of an array or a few struct
+members). For each object, its name and value are printed.
+The @code{--var-print-values} option affects how or whether the value
+field is output. If @var{var_pval} is 0, then print only the names;
+if it is 1, print also their values; and if it is 2, print the name,
+type and value for simple data types, and the name and type for
+arrays, structures and unions.
+
+@item computed-expressions
+The set of computed expressions that have been collected at the
+current trace frame. The @code{--comp-print-values} option affects
+this set like the @code{--var-print-values} option affects the
+@code{explicit-variables} set. See above.
+
+@item registers
+The registers that have been collected at the current trace frame.
+For each register collected, the name and current value are returned.
+The value is formatted according to the @code{--registers-format}
+option. See the @command{-data-list-register-values} command for a
+list of the allowed formats. The default is @samp{x}.
+
+@item tvars
+The trace state variables that have been collected at the current
+trace frame. For each trace state variable collected, the name and
+current value are returned.
+
+@item memory
+The set of memory ranges that have been collected at the current trace
+frame. Its content is a list of tuples. Each tuple represents a
+collected memory range and has the following fields:
+
+@table @code
+@item address
+The start address of the memory range, as hexadecimal literal.
+
+@item length
+The length of the memory range, as decimal literal.
+
+@item contents
+The contents of the memory block, in hex. This field is only present
+if the @code{--memory-contents} option is specified.
+
+@end table
+
+@end table
+
+@subsubheading @value{GDBN} Command
+
+There is no corresponding @value{GDBN} command.
+
+@subsubheading Example
+
@subheading -trace-list-variables
@findex -trace-list-variables
Example output:
@smallexample
-(gdb) -list-features
+(gdb) -list-target-features
^done,result=["async"]
@end smallexample
inferior is not associated with any executable. Such association may
be established with the @samp{-file-exec-and-symbols} command
(@pxref{GDB/MI File Commands}). The command response has a single
-field, @samp{thread-group}, whose value is the identifier of the
+field, @samp{inferior}, whose value is the identifier of the
thread group corresponding to the new inferior.
@subheading Example
@smallexample
@value{GDBP}
-add-inferior
-^done,thread-group="i3"
+^done,inferior="i3"
@end smallexample
@subheading The @code{-interpreter-exec} Command
started with the @code{set data-directory} command, the file will not be
reread.
-@node Installed System-wide Configuration Scripts
+@menu
+* System-wide Configuration Scripts:: Installed System-wide Configuration Scripts
+@end menu
+
+@node System-wide Configuration Scripts
@subsection Installed System-wide Configuration Scripts
@cindex system-wide configuration scripts
to user; the command @code{maint print register-groups} includes the
groups that each register is a member of; and the command @code{maint
print remote-registers} includes the remote target's register numbers
-and offsets in the `G' packets. @xref{Registers,, Registers, gdbint,
-@value{GDBN} Internals}.
+and offsets in the `G' packets.
These commands take an optional parameter, a file name to which to
write the information.
@kindex maint print objfiles
@cindex info for known object files
-@item maint print objfiles
-Print a dump of all known object files. For each object file, this
-command prints its name, address in memory, and all of its psymtabs
-and symtabs.
+@item maint print objfiles @r{[}@var{regexp}@r{]}
+Print a dump of all known object files.
+If @var{regexp} is specified, only print object files whose names
+match @var{regexp}. For each object file, this command prints its name,
+address in memory, and all of its psymtabs and symtabs.
@kindex maint print section-scripts
@cindex info for known .debug_gdb_scripts-loaded scripts
Step with signal @var{sig}. The signal @var{sig} should be two hex digits.
@item t
Stop.
+@item r @var{start},@var{end}
+Step once, and then keep stepping as long as the thread stops at
+addresses between @var{start} (inclusive) and @var{end} (exclusive).
+The remote stub reports a stop reply when either the thread goes out
+of the range or is stopped due to an unrelated reason, such as hitting
+a breakpoint. @xref{range stepping}.
+
+If the range is empty (@var{start} == @var{end}), then the action
+becomes equivalent to the @samp{s} action. In other words,
+single-step once, and report the stop (even if the stepped instruction
+jumps to @var{start}).
+
+(A stop reply may be sent at any point even if the PC is still within
+the stepping range; for example, it is valid to implement this packet
+in a degenerate way as a single instruction step operation.)
+
@end table
The optional argument @var{addr} normally associated with the
@tab @samp{-}
@tab Yes
+@item @samp{qXfer:libraries-svr4:read}
+@tab No
+@tab @samp{-}
+@tab Yes
+
+@item @samp{augmented-libraries-svr4-read}
+@tab No
+@tab @samp{-}
+@tab No
+
@item @samp{qXfer:memory-map:read}
@tab No
@tab @samp{-}
The remote stub understands the @samp{qXfer:libraries-svr4:read} packet
(@pxref{qXfer svr4 library list read}).
+@item augmented-libraries-svr4-read
+The remote stub understands the augmented form of the
+@samp{qXfer:libraries-svr4:read} packet
+(@pxref{qXfer svr4 library list read}).
+
@item qXfer:memory-map:read
The remote stub understands the @samp{qXfer:memory-map:read} packet
(@pxref{qXfer memory map read}).
@anchor{qXfer svr4 library list read}
Access the target's list of loaded libraries when the target is an SVR4
platform. @xref{Library List Format for SVR4 Targets}. The annex part
-of the generic @samp{qXfer} packet must be empty (@pxref{qXfer read}).
+of the generic @samp{qXfer} packet must be empty unless the remote
+stub indicated it supports the augmented form of this packet
+by supplying an appropriate @samp{qSupported} response
+(@pxref{qXfer read}, @ref{qSupported}).
This packet is optional for better performance on SVR4 targets.
@value{GDBN} uses memory read packets to read the SVR4 library list otherwise.
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+If the remote stub indicates it supports the augmented form of this
+packet then the annex part of the generic @samp{qXfer} packet may
+contain a semicolon-separated list of @samp{@var{name}=@var{value}}
+arguments. The currently supported arguments are:
+
+@table @code
+@item start=@var{address}
+A hexadecimal number specifying the address of the @samp{struct
+link_map} to start reading the library list from. If unset or zero
+then the first @samp{struct link_map} in the library list will be
+chosen as the starting point.
+
+@item prev=@var{address}
+A hexadecimal number specifying the address of the @samp{struct
+link_map} immediately preceding the @samp{struct link_map}
+specified by the @samp{start} argument. If unset or zero then
+the remote stub will expect that no @samp{struct link_map}
+exists prior to the starting point.
+
+@end table
+
+Arguments that are not understood by the remote stub will be silently
+ignored.
+
@item qXfer:memory-map:read::@var{offset},@var{length}
@anchor{qXfer memory map read}
Access the target's @dfn{memory-map}. @xref{Memory Map Format}. The
<memory start="@var{addr}" length="@var{length}"/>
@end smallexample
+@item
+A block indicating trace state variable numbered @var{number} has been
+collected:
+
+@smallexample
+<tvar id="@var{number}"/>
+@end smallexample
+
@end itemize
The formal DTD for the traceframe info format is given below:
@smallexample
-<!ELEMENT traceframe-info (memory)* >
+<!ELEMENT traceframe-info (memory | tvar)* >
<!ATTLIST traceframe-info version CDATA #FIXED "1.0">
<!ELEMENT memory EMPTY>
<!ATTLIST memory start CDATA #REQUIRED
length CDATA #REQUIRED>
+<!ELEMENT tvar>
+<!ATTLIST tvar id CDATA #REQUIRED>
@end smallexample
@node Branch Trace Format
* M68K Features::
* Nios II Features::
* PowerPC Features::
+* S/390 and System z Features::
* TIC6x Features::
@end menu
these to present registers @samp{ev0} through @samp{ev31} to the
user.
+@node S/390 and System z Features
+@subsection S/390 and System z Features
+@cindex target descriptions, S/390 features
+@cindex target descriptions, System z features
+
+The @samp{org.gnu.gdb.s390.core} feature is required for S/390 and
+System z targets. It should contain the PSW and the 16 general
+registers. In particular, System z targets should provide the 64-bit
+registers @samp{pswm}, @samp{pswa}, and @samp{r0} through @samp{r15}.
+S/390 targets should provide the 32-bit versions of these registers.
+A System z target that runs in 31-bit addressing mode should provide
+32-bit versions of @samp{pswm} and @samp{pswa}, as well as the general
+register's upper halves @samp{r0h} through @samp{r15h}, and their
+lower halves @samp{r0l} through @samp{r15l}.
+
+The @samp{org.gnu.gdb.s390.fpr} feature is required. It should
+contain the 64-bit registers @samp{f0} through @samp{f15}, and
+@samp{fpc}.
+
+The @samp{org.gnu.gdb.s390.acr} feature is required. It should
+contain the 32-bit registers @samp{acr0} through @samp{acr15}.
+
+The @samp{org.gnu.gdb.s390.linux} feature is optional. It should
+contain the register @samp{orig_r2}, which is 64-bit wide on System z
+targets and 32-bit otherwise. In addition, the feature may contain
+the @samp{last_break} register, whose width depends on the addressing
+mode, as well as the @samp{system_call} register, which is always
+32-bit wide.
+
+The @samp{org.gnu.gdb.s390.tdb} feature is optional. It should
+contain the 64-bit registers @samp{tdb0}, @samp{tac}, @samp{tct},
+@samp{atia}, and @samp{tr0} through @samp{tr15}.
+
@node TIC6x Features
@subsection TMS320C6x Features
@cindex target descriptions, TIC6x features
projects / deliverable / binutils-gdb.git / blobdiff