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authorVladimir Prus <vladimir@codesourcery.com>2007-09-28 06:24:20 +0000
committerVladimir Prus <vladimir@codesourcery.com>2007-09-28 06:24:20 +0000
commit86fa60932212ce4317af61780148ef3c307887d0 (patch)
treef857e3776e99c2c998c1fd4a2643c7517006e93d
parent7f5894e1d00740da63b202c2c787767e495196dd (diff)
downloadgdb-86fa60932212ce4317af61780148ef3c307887d0.tar.gz
* NEW: Mention pending breakpoint changes and
support for breakpoints at multiple locations. * gdb.texinfo (Setting Breakpoints): Revise documentation for pending breakpoints. Document breakpoints with multiple locations.
-rw-r--r--gdb/ChangeLog5
-rw-r--r--gdb/NEWS7
-rw-r--r--gdb/doc/ChangeLog6
-rw-r--r--gdb/doc/gdb.texinfo122
4 files changed, 107 insertions, 33 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e0ae42681e9..526b88e3eba 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2007-09-28 Vladimir Prus <vladimir@codesourcery.com>
+
+ * NEW: Mention pending breakpoint changes and
+ support for breakpoints at multiple locations.
+
2007-09-27 Daniel Jacobowitz <dan@codesourcery.com>
* arm-linux-tdep.c (arm_linux_software_single_step): New.
diff --git a/gdb/NEWS b/gdb/NEWS
index a7c3aab9af9..eb83c1ef81a 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -3,6 +3,13 @@
*** Changes since GDB 6.7
+* Pending breakpoints no longer change their number when their address
+ is resolved.
+
+* GDB now supports breakpoints with multiple locations,
+ including breakpoints on C++ constructors, inside C++ templates,
+ and in inlined functions.
+
*** Changes in GDB 6.6
* Resolved 101 resource leaks, null pointer dereferences, etc. in gdb,
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 67f74b9e3a1..4c8e7cd4cdd 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,9 @@
+2007-09-28 Vladimir Prus <vladimir@codesourcery.com>
+
+ * gdb.texinfo (Setting Breakpoints): Revise
+ documentation for pending breakpoints. Document
+ breakpoints with multiple locations.
+
2007-09-19 Vladimir Prus <vladimir@codesourcery.com>
* gdb.texinfo (Miscellaneous gdb/mi Commands):
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 4378e0c3f55..9b9d16e81aa 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -2991,11 +2991,17 @@ Breakpoint, watchpoint, or catchpoint.
Whether the breakpoint is marked to be disabled or deleted when hit.
@item Enabled or Disabled
Enabled breakpoints are marked with @samp{y}. @samp{n} marks breakpoints
-that are not enabled.
+that are not enabled. An optional @samp{(p)} suffix marks pending
+breakpoints --- breakpoints for which address is either not yet
+resolved, pending load of a shared library, or for which address was
+in a shared library that was since unloaded. Such breakpoint won't
+fire until a shared library that has the symbol or line referred by
+breakpoint is loaded. See below for details.
@item Address
-Where the breakpoint is in your program, as a memory address. If the
-breakpoint is pending (see below for details) on a future load of a shared library, the address
-will be listed as @samp{<PENDING>}.
+Where the breakpoint is in your program, as a memory address. For a
+pending breakpoint whose address is not yet known, this field will
+contain @samp{<PENDING>}. A breakpoint with several locations will
+have @samp{<MULTIPLE>} in this field --- see below for details.
@item What
Where the breakpoint is in the source for your program, as a file and
line number. For a pending breakpoint, the original string passed to
@@ -3032,23 +3038,83 @@ your program. There is nothing silly or meaningless about this. When
the breakpoints are conditional, this is even useful
(@pxref{Conditions, ,Break Conditions}).
+It is possible that a breakpoint correspond to several locations
+in your program. Examples of this situation are:
+
+@itemize @bullet
+
+@item
+For a C@t{++} constructor, the @value{NGCC} compiler generates several
+instances of the function body, used in different cases.
+
+@item
+For a C@t{++} template function, a given line in the function can
+correspond to any number of instantiations.
+
+@item
+For an inlined function, a given source line can correspond to
+several places where that function is inlined.
+
+@end itemize
+
+In all those cases, @value{GDBN} will insert a breakpoint at all
+the relevant locations.
+
+A breakpoint with multiple locations is displayed in the
+breakpoint table using several rows --- one header row, followed
+by one row for each breakpoint location. The header row
+has @samp{<MULTIPLE>} in the address column. The rows for
+individual locations contain the actual addresses for locations,
+and say what functions those locations are in. The number
+column for a location has number in the format
+@var{breakpoint-number}.@var{location-number}.
+
+For example:
+@smallexample
+Num Type Disp Enb Address What
+1 breakpoint keep y <MULTIPLE>
+ stop only if i==1
+ breakpoint already hit 1 time
+1.1 y 0x080486a2 in void foo<int>() at t.cc:8
+1.2 y 0x080486ca in void foo<double>() at t.cc:8
+@end smallexample
+
+Each location can be individually enabled or disabled by passing
+@var{breakpoint-number}.@var{location-number} as argument to the
+@code{enable} and @code{disable} commands.
+
@cindex pending breakpoints
-If a specified breakpoint location cannot be found, it may be due to the fact
-that the location is in a shared library that is yet to be loaded. In such
-a case, you may want @value{GDBN} to create a special breakpoint (known as
-a @dfn{pending breakpoint}) that
-attempts to resolve itself in the future when an appropriate shared library
-gets loaded.
-
-Pending breakpoints are useful to set at the start of your
-@value{GDBN} session for locations that you know will be dynamically loaded
-later by the program being debugged. When shared libraries are loaded,
-a check is made to see if the load resolves any pending breakpoint locations.
-If a pending breakpoint location gets resolved,
-a regular breakpoint is created and the original pending breakpoint is removed.
-
-@value{GDBN} provides some additional commands for controlling pending
-breakpoint support:
+It's quite common to have a breakpoint inside a shared library.
+The shared library may be loaded and unloaded explicitly,
+and possibly repeatedly, as the program is executed. To support
+this use case, @value{GDBN} updates breakpoint locations whenever
+any shared library is loaded or unloaded. Typically, you would
+set a breakpoint in a shared library at the beginning of your
+debugging session, when the library is not loaded, and when the
+symbols from the library are not available. When you try to set
+breakpoint, @value{GDBN} will ask you if you want to set
+a so called @dfn{pending breakpoint} --- breakpoint whose address
+is not yet resolved.
+
+After the program is run, whenever a new shared library is loaded,
+@value{GDBN} reevaluates all the breakpoints. When a newly loaded
+shared library contains the symbol or line referred to by some
+pending breakpoint, that breakpoint is resolved and becomes an
+ordinary breakpoint. When a library is unloaded, all breakpoints
+that refer to its symbols or source lines become pending again.
+
+This logic works for breakpoints with multiple locations, too. For
+example, if you have a breakpoint in a C@t{++} template function, and
+a newly loaded shared library has an instantiation of that template,
+a new location is added to the list of locations for the breakpoint.
+
+Except for having unresolved address, pending breakpoints do not
+differ from regular breakpoints. You can set conditions or commands,
+enable and disable them and perform other breakpoint operations.
+
+@value{GDBN} provides some additional commands for controlling what
+happens when the @samp{break} command cannot resolve breakpoint
+address specification to an address:
@kindex set breakpoint pending
@kindex show breakpoint pending
@@ -3070,19 +3136,9 @@ not affect any pending breakpoints previously created.
Show the current behavior setting for creating pending breakpoints.
@end table
-@cindex operations allowed on pending breakpoints
-Normal breakpoint operations apply to pending breakpoints as well. You may
-specify a condition for a pending breakpoint and/or commands to run when the
-breakpoint is reached. You can also enable or disable
-the pending breakpoint. When you specify a condition for a pending breakpoint,
-the parsing of the condition will be deferred until the point where the
-pending breakpoint location is resolved. Disabling a pending breakpoint
-tells @value{GDBN} to not attempt to resolve the breakpoint on any subsequent
-shared library load. When a pending breakpoint is re-enabled,
-@value{GDBN} checks to see if the location is already resolved.
-This is done because any number of shared library loads could have
-occurred since the time the breakpoint was disabled and one or more
-of these loads could resolve the location.
+The settings above only affect the @code{break} command and its
+variants. Once breakpoint is set, it will be automatically updated
+as shared libraries are loaded and unloaded.
@cindex automatic hardware breakpoints
For some targets, @value{GDBN} can automatically decide if hardware or