Dandling memory pointers in Ada catchpoints with GDB/MI.
authorJoel Brobecker <brobecker@adacore.com>
Wed, 30 Oct 2013 10:18:24 +0000 (11:18 +0100)
committerJoel Brobecker <brobecker@adacore.com>
Mon, 11 Nov 2013 15:19:07 +0000 (19:19 +0400)
commit2df4d1d5c4393fd06c2bffe75499e70a8d8ac8a8
treed7129814a8a20fde9eb916a1d693e7a78c844902
parent99c1d4518bf2ff230eaa6ee54c08e85f2d6c008e
Dandling memory pointers in Ada catchpoints with GDB/MI.

When using the GDB/MI commands to insert a catchpoint on a specific
Ada exception, any re-evaluation of that catchpoint (for instance
a re-evaluation performed after a shared library got mapped by the
inferior) fails. For instance, with any Ada program:

    (gdb)
    -catch-exception -e program_error
    ^done,bkptno="1",bkpt={[...]}
    (gdb)
    -exec-run
    =thread-group-started,id="i1",pid="28315"
    =thread-created,id="1",group-id="i1"
    ^running
    *running,thread-id="all"
    (gdb)
    =library-loaded,[...]
    &"warning: failed to reevaluate internal exception condition for catchpoint 1: No definition of \"exec\" in current context.\n"
    &"warning: failed to reevaluate internal exception condition for catchpoint 1: No definition of \"exec\" in current context.\n"
    [...]

The same is true if using an Ada exception catchpoint.

The problem comes from the fact that that we deallocate the strings
given as arguments to create_ada_exception_catchpoint, while the latter
just makes shallow copies of those strings, thus creating dandling
pointers.

This patch fixes the issue by passing freshly allocated strings to
create_ada_exception_catchpoint, while at the same time updating
create_ada_exception_catchpoint's documentation to make it clear
that deallocating the strings is no longer the responsibility of
the caller.

gdb/ChangeLog:

        * ada-lang.c (create_ada_exception_catchpoint): Enhance
        the documentation of fields "except_string" and "condition".
        * mi/mi-cmd-catch.c (mi_cmd_catch_assert): Reallocate
        CONDITION on the heap before passing it to
        create_ada_exception_catchpoint.
        (mi_cmd_catch_exception): Likewise for EXCEPTION_NAME and
        CONDITION.

gdb/testsuite/ChangeLog:

        * gdb.ada/mi_ex_cond: New testcase.

Tested on x86_64-linux.  The "-break-list" test FAILs without
this patch.
gdb/ChangeLog
gdb/ada-lang.c
gdb/mi/mi-cmd-catch.c
gdb/testsuite/ChangeLog
gdb/testsuite/gdb.ada/mi_ex_cond.exp [new file with mode: 0644]
gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb [new file with mode: 0644]
gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads [new file with mode: 0644]