gdb and binutils branch master updated. 31aa7e4ee988b175da848cee7cff6cfb28a5aa99

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https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=31aa7e4ee988b175da848cee7cff6cfb28a5aa99

commit 31aa7e4ee988b175da848cee7cff6cfb28a5aa99
Author: Joel Brobecker <brobecker@adacore.com>
Date:   Sat Feb 15 19:09:58 2014 +0400

    DWARF: Read constant-class addresses correctly
    
    Starting with DWARF version 4, the description of the DW_AT_high_pc
    attribute was amended to say:
    
       if it is of class constant, the value is an unsigned integer offset
       which when added to the low PC gives the address of the first
       location past the last instruction associated with the entity.
    
    A change was made in Apr 27th, 2012 to reflect that change:
    
      | commit 91da14142c0171e58a91ad58a32fd010b700e761
      | Author: Mark Wielaard <mjw@redhat.com>
      | Date:   Fri Apr 27 18:55:19 2012 +0000
      |
      |     * dwarf2read.c (dwarf2_get_pc_bounds): Check DW_AT_high_pc form to
      |     see whether it is an address or a constant offset from DW_AT_low_pc.
      |     (dwarf2_record_block_ranges): Likewise.
      |     (read_partial_die): Likewise.
    
    Unfortunately, this new interpretation is now used regardless of
    the CU's DWARF version. It turns out that one of WindRiver's compilers
    (FTR: Diabdata 4.4) is generating DWARF version 2 info with
    DW_AT_high_pc attributes improperly using the data4 form. Because of
    that, we miscompute all high PCs incorrectly. This leads to a lot of
    symtabs having overlapping ranges, which in turn causes havoc in
    pc-to-symtab-and-line translations.
    
    One visible effect is when inserting a breakpoint on a given function:
    
        (gdb) b world
        Breakpoint 1 at 0x4005c4
    
    The source location of the breakpoint is missing. The output should be:
    
        (gdb) b world
        Breakpoint 1 at 0x4005c8: file dw2-rel-hi-pc-world.c, line 24.
    
    What happens in this case is that the pc-to-SAL translation first
    starts be trying to find the symtab associated to our PC using
    each symtab's ranges. Because of the high_pc miscomputation,
    many symtabs end up matching, and the heuristic trying to select
    the most probable one unfortunately returns one that is unrelated
    (it really had no change in this case to do any better). Once we
    have the wrong symtab, the start searching the associated linetable,
    where the addresses are correct, thus finding no match, and therefore
    no SAL.
    
    This patch is an attempt at handling the situation as gracefully
    as we can, without guarantees.  It introduces a new function
    "attr_value_as_address" which uses the correct accessor for getting
    the value of a given attribute.  It then adjust the code throughout
    this unit to use this function instead of assuming that addresses always
    have the DW_FORM_addr format.
    
    It also fixes the original issue of miscomputing the high_pc
    by limiting the new interpretation of constant form DW_AT_high_pc
    attributes to units using DWARF version 4 or later.
    
    gdb/ChangeLog:
    
            * dwarf2read.c (attr_value_as_address): New function.
            (dwarf2_find_base_address, read_call_site_scope): Use
            attr_value_as_address in place of DW_ADDR.
            (dwarf2_get_pc_bounds): Use attr_value_as_address to get
            the low and high addresses.  Slight rework of the handling
            of the high pc being a constant form, and limit it to
            DWARF verson 4 or higher.
            (dwarf2_record_block_ranges): Likewise.
            (read_partial_die): Likewise.
            (new_symbol_full): Use attr_value_as_address in place of DW_ADDR.
    
    gdb/testsuite/ChangeLog:
    
            * gdb.dwarf2/dw2-abs-hi-pc-hello-dbg.S: New file.
            * gdb.dwarf2/dw2-abs-hi-pc-hello.c: New file.
            * gdb.dwarf2/dw2-abs-hi-pc-world-dbg.S: New file.
            * gdb.dwarf2/dw2-abs-hi-pc-world.c: New file.
            * gdb.dwarf2/dw2-abs-hi-pc.c: New file.
            * gdb.dwarf2/dw2-abs-hi-pc.exp: New file.
    
    Tested on x86_64-linux.

-----------------------------------------------------------------------

Summary of changes:
 gdb/ChangeLog                                      |   13 ++
 gdb/dwarf2read.c                                   |   76 ++++++----
 gdb/testsuite/ChangeLog                            |    9 ++
 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-hello-dbg.S |  151 ++++++++++++++++++++
 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-hello.c     |   28 ++++
 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-world-dbg.S |  151 ++++++++++++++++++++
 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-world.c     |   28 ++++
 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc.c           |   28 ++++
 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc.exp         |   35 +++++
 9 files changed, 491 insertions(+), 28 deletions(-)
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-hello-dbg.S
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-hello.c
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-world-dbg.S
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc-world.c
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc.c
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc.exp


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