[Bug breakpoints/21555] "error re-setting breakpoint" on PIE executables

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=21555

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Yao Qi <qiyao@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=46a62268b87bd5e8215636b695380bca9a9f3b63

commit 46a62268b87bd5e8215636b695380bca9a9f3b63
Author: Yao Qi <yao.qi@linaro.org>
Date:   Tue Jul 25 11:38:50 2017 +0100

    Catch exceptions thrown from gdbarch_skip_prologue

    PR 21555 is caused by the exception during the prologue analysis when
re-set
    a breakpoint.

    (gdb) bt
     #0  memory_error_message (err=TARGET_XFER_E_IO, gdbarch=0x153db50,
memaddr=93824992233232) at ../../binutils-gdb/gdb/corefile.c:192
     #1  0x00000000005718ed in memory_error (err=TARGET_XFER_E_IO,
memaddr=memaddr@entry=93824992233232) at ../../binutils-gdb/gdb/corefile.c:220
     #2  0x00000000005719d6 in read_memory_object
(object=object@entry=TARGET_OBJECT_CODE_MEMORY, memaddr=93824992233232,
memaddr@entry=1, myaddr=myaddr@entry=0x7fffffffd0a0 "P\333S\001",
len=len@entry=1) at ../../binutils-gdb/gdb/corefile.c:259
     #3  0x0000000000571c6e in read_code (len=1, myaddr=0x7fffffffd0a0
"P\333S\001", memaddr=<optimized out>) at ../../binutils-gdb/gdb/corefile.c:287
     #4  read_code_unsigned_integer (memaddr=memaddr@entry=93824992233232,
len=len@entry=1, byte_order=byte_order@entry=BFD_ENDIAN_LITTLE)                
         at ../../binutils-gdb/gdb/corefile.c:362
     #5  0x000000000041d4a0 in amd64_analyze_prologue
(gdbarch=gdbarch@entry=0x153db50, pc=pc@entry=93824992233232,
current_pc=current_pc@entry=18446744073709551615,
cache=cache@entry=0x7fffffffd1e0) at ../../binutils-gdb/gdb/amd64-tdep.c:2310
     #6  0x000000000041e404 in amd64_skip_prologue (gdbarch=0x153db50,
start_pc=93824992233232) at ../../binutils-gdb/gdb/amd64-tdep.c:2459
     #7  0x000000000067bfb0 in skip_prologue_sal (sal=sal@entry=0x7fffffffd4e0)
at ../../binutils-gdb/gdb/symtab.c:3628
     #8  0x000000000067c4d8 in find_function_start_sal
(sym=sym@entry=0x1549960, funfirstline=1) at
../../binutils-gdb/gdb/symtab.c:3501
     #9  0x000000000060999d in symbol_to_sal
(result=result@entry=0x7fffffffd5f0, funfirstline=<optimized out>,
sym=sym@entry=0x1549960) at ../../binutils-gdb/gdb/linespec.c:3860
    ....
     #16 0x000000000054b733 in location_to_sals (b=b@entry=0x15792d0,
location=0x157c230, search_pspace=search_pspace@entry=0x1148120,
found=found@entry=0x7fffffffdc64) at ../../binutils-gdb/gdb/breakpoint.c:14211
     #17 0x000000000054c1f5 in breakpoint_re_set_default (b=0x15792d0) at
../../binutils-gdb/gdb/breakpoint.c:14301
     #18 0x00000000005412a9 in breakpoint_re_set_one
(bint=bint@entry=0x15792d0) at ../../binutils-gdb/gdb/breakpoint.c:14412

    This problem can be fixed by

     - either each prologue analyzer doesn't throw exception,
     - or catch the exception thrown from gdbarch_skip_prologue,

    I choose the latter because the former needs to fix *every* prologue
    analyzer to not throw exception.

    This error can be reproduced by changing reread.exp.  The test reread.exp
    has already test that breakpoint can be reset correctly after the
    executable is re-read.  This patch extends this test by compiling test c
    file with and without -fPIE.

    (gdb) run ^M
    The program being debugged has been started already.^M
    Start it from the beginning? (y or n) y^M
    x86_64/gdb/testsuite/outputs/gdb.base/reread/reread' has changed;
re-reading symbols.
    Error in re-setting breakpoint 1: Cannot access memory at address
0x555555554790^M
    Error in re-setting breakpoint 2: Cannot access memory at address
0x555555554790^M
    Starting program:
/scratch/yao/gdb/build-git/x86_64/gdb/testsuite/outputs/gdb.base/reread/reread
^M
    This is foo^M
    [Inferior 1 (process 27720) exited normally]^M
    (gdb) FAIL: gdb.base/reread.exp: opts= "-fPIE" "ldflags=-pie" : run to
foo() second time (the program exited)

    This patch doesn't re-indent the code, to keep the patch simple.

    gdb:

    2017-07-25  Yao Qi  <yao.qi@linaro.org>

        PR gdb/21555
        * arch-utils.c (gdbarch_skip_prologue_noexcept): New function.
        * arch-utils.h (gdbarch_skip_prologue_noexcept): Declare.
        * infrun.c: Include arch-utils.h
        (handle_step_into_function): Call gdbarch_skip_prologue_noexcept.
        (handle_step_into_function_backward): Likewise.
        * symtab.c (skip_prologue_sal): Likewise.

    gdb/testsuite:

    2017-07-25  Yao Qi  <yao.qi@linaro.org>

        PR gdb/21555
        * gdb.base/reread.exp: Wrap the whole test with two kinds of
        compilation flags, with -fPIE and without -fPIE.

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