MIPS: Keep the ISA bit in compressed code addresses

1. Background information

The MIPS architecture, as originally designed and implemented in
mid-1980s has a uniform instruction word size that is 4 bytes, naturally
aligned.  As such all MIPS instructions are located at addresses that
have their bits #1 and #0 set to zeroes, and any attempt to execute an
instruction from an address that has any of the two bits set to one
causes an address error exception.  This may for example happen when a
jump-register instruction is executed whose register value used as the
jump target has any of these bits set.

Then in mid 1990s LSI sought a way to improve code density for their
TinyRISC family of MIPS cores and invented an alternatively encoded
instruction set in a joint effort with MIPS Technologies (then a
subsidiary of SGI).  The new instruction set has been named the MIPS16
ASE (Application-Specific Extension) and uses a variable instruction
word size, which is 2 bytes (as the name of the ASE suggests) for most,
but there are a couple of exceptions that take 4 bytes, and then most of
the 2-byte instructions can be treated with a 2-byte extension prefix to
expand the range of the immediate operands used.

As a result instructions are no longer 4-byte aligned, instead they are
aligned to a multiple of 2.  That left the bit #0 still unused for code
references, be it for the standard MIPS (i.e. as originally invented) or
for the MIPS16 instruction set, and based on that observation a clever
trick was invented that on one hand allowed the processor to be
seamlessly switched between the two instruction sets at any time at the
run time while on the other avoided the introduction of any special
control register to do that.

So it is the bit #0 of the instruction address that was chosen as the
selector and named the ISA bit.  Any instruction executed at an even
address is interpreted as a standard MIPS instruction (the address still
has to have its bit #1 clear), any instruction executed at an odd
address is interpreted as a MIPS16 instruction.

To switch between modes ordinary jump instructions are used, such as
used for function calls and returns, specifically the bit #0 of the
source register used in jump-register instructions selects the execution
(ISA) mode for the following piece of code to be interpreted in.
Additionally new jump-immediate instructions were added that flipped the
ISA bit to select the opposite mode upon execution.  They were
considered necessary to avoid the need to make register jumps in all
cases as the original jump-immediate instructions provided no way to
change the bit #0 at all.

This was all important for cases where standard MIPS and MIPS16 code had
to be mixed, either for compatibility with the existing binary code base
or to access resources not reachable from MIPS16 code (the MIPS16
instruction set only provides access to general-purpose registers, and
not for example floating-point unit registers or privileged coprocessor
0 registers) -- pieces of code in the opposite mode can be executed as
ordinary subroutine calls.

A similar approach has been more recently adopted for the MIPS16
replacement instruction set defined as the so called microMIPS ASE.
This is another instruction set encoding introduced to the MIPS
architecture.  Just like the MIPS16 ASE, the microMIPS instruction set
uses a variable-length encoding, where each instruction takes a multiple
of 2 bytes.  The ISA bit has been reused and for microMIPS-capable
processors selects between the standard MIPS and the microMIPS mode
instead.

2. Statement of the problem

To put it shortly, MIPS16 and microMIPS code pointers used by GDB are
different to these observed at the run time.  This results in the same
expressions being evaluated producing different results in GDB and in
the program being debugged.  Obviously it's the results obtained at the
run time that are correct (they define how the program behaves) and
therefore by definition the results obtained in GDB are incorrect.

A bit longer description will record that obviously at the run time the
ISA bit has to be set correctly (refer to background information above
if unsure why so) or the program will not run as expected.  This is
recorded in all the executable file structures used at the run time: the
dynamic symbol table (but not always the static one!), the GOT, and
obviously in all the addresses embedded in code or data of the program
itself, calculated by applying the appropriate relocations at the static
link time.

While a program is being processed by GDB, the ISA bit is stripped off
from any code addresses, presumably to make them the same as the
respective raw memory byte address used by the processor to access the
instruction in the instruction fetch access cycle.  This stripping is
actually performed outside GDB proper, in BFD, specifically
_bfd_mips_elf_symbol_processing (elfxx-mips.c, see the piece of code at
the very bottom of that function, starting with an: "If this is an
odd-valued function symbol, assume it's a MIPS16 or microMIPS one."
comment).

This function is also responsible for symbol table dumps made by
`objdump' too, so you'll never see the ISA bit reported there by that
tool, you need to use `readelf'.

This is however unlike what is ever done at the run time, the ISA bit
once present is never stripped off, for example a cast like this:

(short *) main

will not strip the ISA bit off and if the resulting pointer is intended
to be used to access instructions as data, for example for software
instruction decoding (like for fault recovery or emulation in a signal
handler) or for self-modifying code then the bit still has to be
stripped off by an explicit AND operation.

This is probably best illustrated with a simple real program example.
Let's consider the following simple program:

$ cat foobar.c
int __attribute__ ((mips16)) foo (void)
{
  return 1;
}

int __attribute__ ((mips16)) bar (void)
{
  return 2;
}

int __attribute__ ((nomips16)) foo32 (void)
{
  return 3;
}

int (*foo32p) (void) = foo32;
int (*foop) (void) = foo;
int fooi = (int) foo;

int
main (void)
{
  return foop ();
}
$

This is plain C with no odd tricks, except from the instruction mode
attributes.  They are not necessary to trigger this problem, I just put
them here so that the program can be contained in a single source file
and to make it obvious which function is MIPS16 code and which is not.

Let's try it with Linux, so that everyone can repeat this experiment:

$ mips-linux-gnu-gcc -mips16 -g -O2 -o foobar foobar.c
$

Let's have a look at some interesting symbols:

$ mips-linux-gnu-readelf -s foobar | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 7 entries:
Symbol table '.symtab' contains 95 entries:
    55: 00000000     0 FILE    LOCAL  DEFAULT  ABS foobar.c
    66: 0040068c     4 FUNC    GLOBAL DEFAULT [MIPS16]    12 bar
    68: 00410848     4 OBJECT  GLOBAL DEFAULT   21 foo32p
    70: 00410844     4 OBJECT  GLOBAL DEFAULT   21 foop
    78: 00400684     8 FUNC    GLOBAL DEFAULT   12 foo32
    80: 00400680     4 FUNC    GLOBAL DEFAULT [MIPS16]    12 foo
    88: 00410840     4 OBJECT  GLOBAL DEFAULT   21 fooi
$

Hmm, no sight of the ISA bit, but notice how foo and bar (but not
foo32!) have been marked as MIPS16 functions (ELF symbol structure's
`st_other' field is used for that).

So let's try to run and poke at this program with GDB.  I'll be using a
native system for simplicity (I'll be using ellipses here and there to
remove unrelated clutter):

$ ./foobar
$ echo $?
1
$

So far, so good.

$ gdb ./foobar
[...]
(gdb) break main
Breakpoint 1 at 0x400490: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar

Breakpoint 1, main () at foobar.c:23
23        return foop ();
(gdb)

Yay, it worked!  OK, so let's poke at it:

(gdb) print main
$1 = {int (void)} 0x400490 <main>
(gdb) print foo32
$2 = {int (void)} 0x400684 <foo32>
(gdb) print foo32p
$3 = (int (*)(void)) 0x400684 <foo32>
(gdb) print bar
$4 = {int (void)} 0x40068c <bar>
(gdb) print foo
$5 = {int (void)} 0x400680 <foo>
(gdb) print foop
$6 = (int (*)(void)) 0x400681 <foo>
(gdb)

A-ha!  Here's the difference and finally the ISA bit!

(gdb) print /x fooi
$7 = 0x400681
(gdb) p/x $pc
p/x $pc
$8 = 0x400491
(gdb)

And here as well...

(gdb) advance foo
foo () at foobar.c:4
4       }
(gdb) disassemble
Dump of assembler code for function foo:
   0x00400680 <+0>:     jr      ra
   0x00400682 <+2>:     li      v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0  foo () at foobar.c:4
main () at foobar.c:24
24      }
Value returned is $9 = 1
(gdb) continue
Continuing.
[Inferior 1 (process 14103) exited with code 01]
(gdb)

So let's be a bit inquisitive...

(gdb) run
Starting program: .../foobar

Breakpoint 1, main () at foobar.c:23
23        return foop ();
(gdb)

Actually we do not like to run foo here at all.  Let's run bar instead!

(gdb) set foop = bar
(gdb) print foop
$10 = (int (*)(void)) 0x40068c <bar>
(gdb)

Hmm, no ISA bit.  Is it going to work?

(gdb) advance bar
bar () at foobar.c:9
9       }
(gdb) p/x $pc
$11 = 0x40068c
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068c <+0>:     jr      ra
   0x0040068e <+2>:     li      v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0  bar () at foobar.c:9

Program received signal SIGILL, Illegal instruction.
bar () at foobar.c:9
9       }
(gdb)

Oops!

(gdb) p/x $pc
$12 = 0x40068c
(gdb)

We're still there!

(gdb) continue
Continuing.

Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)

So let's try something else:

(gdb) run
Starting program: .../foobar

Breakpoint 1, main () at foobar.c:23
23        return foop ();
(gdb) set foop = foo
(gdb) advance foo
foo () at foobar.c:4
4       }
(gdb) disassemble
Dump of assembler code for function foo:
=> 0x00400680 <+0>:     jr      ra
   0x00400682 <+2>:     li      v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0  foo () at foobar.c:4

Program received signal SIGILL, Illegal instruction.
foo () at foobar.c:4
4       }
(gdb) continue
Continuing.

Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)

The same problem!

(gdb) run
Starting program:
/net/build2-lucid-cs/scratch/macro/mips-linux-fsf-gcc/isa-bit/foobar

Breakpoint 1, main () at foobar.c:23
23        return foop ();
(gdb) set foop = foo32
(gdb) advance foo32
foo32 () at foobar.c:14
14      }
(gdb) disassemble
Dump of assembler code for function foo32:
=> 0x00400684 <+0>:     jr      ra
   0x00400688 <+4>:     li      v0,3
End of assembler dump.
(gdb) finish
Run till exit from #0  foo32 () at foobar.c:14
main () at foobar.c:24
24      }
Value returned is $14 = 3
(gdb) continue
Continuing.
[Inferior 1 (process 14113) exited with code 03]
(gdb)

That did work though, so it's the ISA bit only!

(gdb) quit

Enough!

That's the tip of the iceberg only though.  So let's rebuild the
executable with some dynamic symbols:

$ mips-linux-gnu-gcc -mips16 -Wl,--export-dynamic -g -O2 -o foobar-dyn foobar.c
$ mips-linux-gnu-readelf -s foobar-dyn | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 32 entries:
     6: 004009cd     4 FUNC    GLOBAL DEFAULT   12 bar
     8: 00410b88     4 OBJECT  GLOBAL DEFAULT   21 foo32p
     9: 00410b84     4 OBJECT  GLOBAL DEFAULT   21 foop
    15: 004009c4     8 FUNC    GLOBAL DEFAULT   12 foo32
    17: 004009c1     4 FUNC    GLOBAL DEFAULT   12 foo
    25: 00410b80     4 OBJECT  GLOBAL DEFAULT   21 fooi
Symbol table '.symtab' contains 95 entries:
    55: 00000000     0 FILE    LOCAL  DEFAULT  ABS foobar.c
    69: 004009cd     4 FUNC    GLOBAL DEFAULT   12 bar
    71: 00410b88     4 OBJECT  GLOBAL DEFAULT   21 foo32p
    72: 00410b84     4 OBJECT  GLOBAL DEFAULT   21 foop
    79: 004009c4     8 FUNC    GLOBAL DEFAULT   12 foo32
    81: 004009c1     4 FUNC    GLOBAL DEFAULT   12 foo
    89: 00410b80     4 OBJECT  GLOBAL DEFAULT   21 fooi
$

OK, now the ISA bit is there for a change, but the MIPS16 `st_other'
attribute gone, hmm...  What does `objdump' do then:

$ mips-linux-gnu-objdump -Tt foobar-dyn | egrep 'SYMBOL|foo|bar'
foobar-dyn:     file format elf32-tradbigmips
SYMBOL TABLE:
00000000 l    df *ABS*  00000000              foobar.c
004009cc g     F .text  00000004              0xf0 bar
00410b88 g     O .data  00000004              foo32p
00410b84 g     O .data  00000004              foop
004009c4 g     F .text  00000008              foo32
004009c0 g     F .text  00000004              0xf0 foo
00410b80 g     O .data  00000004              fooi
DYNAMIC SYMBOL TABLE:
004009cc g    DF .text  00000004  Base        0xf0 bar
00410b88 g    DO .data  00000004  Base        foo32p
00410b84 g    DO .data  00000004  Base        foop
004009c4 g    DF .text  00000008  Base        foo32
004009c0 g    DF .text  00000004  Base        0xf0 foo
00410b80 g    DO .data  00000004  Base        fooi
$

Hmm, the attribute (0xf0, printed raw) is back, and the ISA bit gone
again.

Let's have a look at some DWARF-2 records GDB uses (I'll be stripping
off a lot here for brevity) -- debug info:

$ mips-linux-gnu-readelf -wi foobar
Contents of the .debug_info section:
[...]
  Compilation Unit @ offset 0x88:
   Length:        0xbb (32-bit)
   Version:       4
   Abbrev Offset: 62
   Pointer Size:  4
 <0><93>: Abbrev Number: 1 (DW_TAG_compile_unit)
    <94>   DW_AT_producer    : (indirect string, offset: 0x19e): GNU C 4.8.0 20120513 (experimental) -meb -mips16 -march=mips32r2 -mhard-float -mllsc -mplt -mno-synci -mno-shared -mabi=32 -g -O2
    <98>   DW_AT_language    : 1        (ANSI C)
    <99>   DW_AT_name        : (indirect string, offset: 0x190): foobar.c
    <9d>   DW_AT_comp_dir    : (indirect string, offset: 0x225): [...]
    <a1>   DW_AT_ranges      : 0x0
    <a5>   DW_AT_low_pc      : 0x0
    <a9>   DW_AT_stmt_list   : 0x27
 <1><ad>: Abbrev Number: 2 (DW_TAG_subprogram)
    <ae>   DW_AT_external    : 1
    <ae>   DW_AT_name        : foo
    <b2>   DW_AT_decl_file   : 1
    <b3>   DW_AT_decl_line   : 1
    <b4>   DW_AT_prototyped  : 1
    <b4>   DW_AT_type        : <0xc2>
    <b8>   DW_AT_low_pc      : 0x400680
    <bc>   DW_AT_high_pc     : 0x400684
    <c0>   DW_AT_frame_base  : 1 byte block: 9c         (DW_OP_call_frame_cfa)
    <c2>   DW_AT_GNU_all_call_sites: 1
 <1><c2>: Abbrev Number: 3 (DW_TAG_base_type)
    <c3>   DW_AT_byte_size   : 4
    <c4>   DW_AT_encoding    : 5        (signed)
    <c5>   DW_AT_name        : int
 <1><c9>: Abbrev Number: 4 (DW_TAG_subprogram)
    <ca>   DW_AT_external    : 1
    <ca>   DW_AT_name        : (indirect string, offset: 0x18a): foo32
    <ce>   DW_AT_decl_file   : 1
    <cf>   DW_AT_decl_line   : 11
    <d0>   DW_AT_prototyped  : 1
    <d0>   DW_AT_type        : <0xc2>
    <d4>   DW_AT_low_pc      : 0x400684
    <d8>   DW_AT_high_pc     : 0x40068c
    <dc>   DW_AT_frame_base  : 1 byte block: 9c         (DW_OP_call_frame_cfa)
    <de>   DW_AT_GNU_all_call_sites: 1
 <1><de>: Abbrev Number: 2 (DW_TAG_subprogram)
    <df>   DW_AT_external    : 1
    <df>   DW_AT_name        : bar
    <e3>   DW_AT_decl_file   : 1
    <e4>   DW_AT_decl_line   : 6
    <e5>   DW_AT_prototyped  : 1
    <e5>   DW_AT_type        : <0xc2>
    <e9>   DW_AT_low_pc      : 0x40068c
    <ed>   DW_AT_high_pc     : 0x400690
    <f1>   DW_AT_frame_base  : 1 byte block: 9c         (DW_OP_call_frame_cfa)
    <f3>   DW_AT_GNU_all_call_sites: 1
 <1><f3>: Abbrev Number: 5 (DW_TAG_subprogram)
    <f4>   DW_AT_external    : 1
    <f4>   DW_AT_name        : (indirect string, offset: 0x199): main
    <f8>   DW_AT_decl_file   : 1
    <f9>   DW_AT_decl_line   : 21
    <fa>   DW_AT_prototyped  : 1
    <fa>   DW_AT_type        : <0xc2>
    <fe>   DW_AT_low_pc      : 0x400490
    <102>   DW_AT_high_pc     : 0x4004a4
    <106>   DW_AT_frame_base  : 1 byte block: 9c        (DW_OP_call_frame_cfa)
    <108>   DW_AT_GNU_all_tail_call_sites: 1
[...]
$

-- no sign of the ISA bit anywhere -- frame info:

$ mips-linux-gnu-readelf -wf foobar
[...]
Contents of the .debug_frame section:

00000000 0000000c ffffffff CIE
  Version:               1
  Augmentation:          ""
  Code alignment factor: 1
  Data alignment factor: -4
  Return address column: 31

  DW_CFA_def_cfa_register: r29
  DW_CFA_nop

00000010 0000000c 00000000 FDE cie=00000000 pc=00400680..00400684

00000020 0000000c 00000000 FDE cie=00000000 pc=00400684..0040068c

00000030 0000000c 00000000 FDE cie=00000000 pc=0040068c..00400690

00000040 00000018 00000000 FDE cie=00000000 pc=00400490..004004a4
  DW_CFA_advance_loc: 6 to 00400496
  DW_CFA_def_cfa_offset: 32
  DW_CFA_offset: r31 at cfa-4
  DW_CFA_advance_loc: 6 to 0040049c
  DW_CFA_restore: r31
  DW_CFA_def_cfa_offset: 0
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
[...]
$

-- no sign of the ISA bit anywhere -- range info (GDB doesn't use arange):

$ mips-linux-gnu-readelf -wR foobar
Contents of the .debug_ranges section:

    Offset   Begin    End
    00000000 00400680 00400690
    00000000 00400490 004004a4
    00000000 <End of list>

$

-- no sign of the ISA bit anywhere -- line info:

$ mips-linux-gnu-readelf -wl foobar
Raw dump of debug contents of section .debug_line:
[...]
  Offset:                      0x27
  Length:                      78
  DWARF Version:               2
  Prologue Length:             31
  Minimum Instruction Length:  1
  Initial value of 'is_stmt':  1
  Line Base:                   -5
  Line Range:                  14
  Opcode Base:                 13

 Opcodes:
  Opcode 1 has 0 args
  Opcode 2 has 1 args
  Opcode 3 has 1 args
  Opcode 4 has 1 args
  Opcode 5 has 1 args
  Opcode 6 has 0 args
  Opcode 7 has 0 args
  Opcode 8 has 0 args
  Opcode 9 has 1 args
  Opcode 10 has 0 args
  Opcode 11 has 0 args
  Opcode 12 has 1 args

 The Directory Table is empty.

 The File Name Table:
  Entry Dir     Time    Size    Name
  1     0       0       0       foobar.c

 Line Number Statements:
  Extended opcode 2: set Address to 0x400681
  Special opcode 6: advance Address by 0 to 0x400681 and Line by 1 to 2
  Special opcode 7: advance Address by 0 to 0x400681 and Line by 2 to 4
  Special opcode 55: advance Address by 3 to 0x400684 and Line by 8 to 12
  Special opcode 7: advance Address by 0 to 0x400684 and Line by 2 to 14
  Advance Line by -7 to 7
  Special opcode 131: advance Address by 9 to 0x40068d and Line by 0 to 7
  Special opcode 7: advance Address by 0 to 0x40068d and Line by 2 to 9
  Advance PC by 3 to 0x400690
  Extended opcode 1: End of Sequence

  Extended opcode 2: set Address to 0x400491
  Advance Line by 21 to 22
  Copy
  Special opcode 6: advance Address by 0 to 0x400491 and Line by 1 to 23
  Special opcode 60: advance Address by 4 to 0x400495 and Line by -1 to 22
  Special opcode 34: advance Address by 2 to 0x400497 and Line by 1 to 23
  Special opcode 62: advance Address by 4 to 0x40049b and Line by 1 to 24
  Special opcode 32: advance Address by 2 to 0x40049d and Line by -1 to 23
  Special opcode 6: advance Address by 0 to 0x40049d and Line by 1 to 24
  Advance PC by 7 to 0x4004a4
  Extended opcode 1: End of Sequence
[...]

-- a-ha, the ISA bit is there!  However it's not always right for some
reason, I don't have a small test case to show it, but here's an excerpt
from MIPS16 libc, a prologue of a function:

00019630 <__libc_init_first>:
   19630:       e8a0            jrc     ra
   19632:       6500            nop

00019634 <_init>:
   19634:       f000 6a11       li      v0,17
   19638:       f7d8 0b08       la      v1,15e00 <_DYNAMIC+0x15c54>
   1963c:       f400 3240       sll     v0,16
   19640:       e269            addu    v0,v1
   19642:       659a            move    gp,v0
   19644:       64f6            save    48,ra,s0-s1
   19646:       671c            move    s0,gp
   19648:       d204            sw      v0,16(sp)
   1964a:       f352 984c       lw      v0,-27828(s0)
   1964e:       6724            move    s1,a0

and the corresponding DWARF-2 line info:

 Line Number Statements:
  Extended opcode 2: set Address to 0x19631
  Advance Line by 44 to 45
  Copy
  Special opcode 8: advance Address by 0 to 0x19631 and Line by 3 to 48
  Special opcode 66: advance Address by 4 to 0x19635 and Line by 5 to 53
  Advance PC by constant 17 to 0x19646
  Special opcode 25: advance Address by 1 to 0x19647 and Line by 6 to 59
  Advance Line by -6 to 53
  Special opcode 33: advance Address by 2 to 0x19649 and Line by 0 to 53
  Special opcode 39: advance Address by 2 to 0x1964b and Line by 6 to 59
  Advance Line by -6 to 53
  Special opcode 61: advance Address by 4 to 0x1964f and Line by 0 to 53

-- see that "Advance PC by constant 17" there?  It clears the ISA bit,
however code at 0x19646 is not standard MIPS code at all.  For some
reason the constant is always 17, I've never seen DW_LNS_const_add_pc
used with any other value -- is that a binutils bug or what?

3. Solution:

I think we should retain the value of the ISA bit in code references,
that is effectively treat them as cookies as they indeed are (although
trivially calculated) rather than raw memory byte addresses.

In a perfect world both the static symbol table and the respective
DWARF-2 records should be fixed to include the ISA bit in all the cases.
I think however that this is infeasible.

All the uses of `_bfd_mips_elf_symbol_processing' can not necessarily be
tracked down.  This function is used by `elf_slurp_symbol_table' that in
turn is used by `bfd_canonicalize_symtab' and
`bfd_canonicalize_dynamic_symtab', which are public interfaces.

Similarly DWARF-2 records are used outside GDB, one notable if a bit
questionable is the exception unwinder (libgcc/unwind-dw2.c) -- I have
identified at least bits in `execute_cfa_program' and
`uw_frame_state_for', both around the calls to `_Unwind_IsSignalFrame',
that would need an update as they effectively flip the ISA bit freely;
see also the comment about MASK_RETURN_ADDR in gcc/config/mips/mips.h.
But there may be more places.  Any change in how DWARF-2 records are
produced would require an update there and would cause compatibility
problems with libgcc.a binaries already distributed; given that this is
a static library a complex change involving function renames would
likely be required.

I propose therefore to accept the existing inconsistencies and deal with
them entirely within GDB.  I have figured out that the ISA bit lost in
various places can still be recovered as long as we have symbol
information -- that'll have the `st_other' attribute correctly set to
one of standard MIPS/MIPS16/microMIPS encoding.

Here's the resulting change.  It adds a couple of new `gdbarch' hooks,
one to update symbol information with the ISA bit lost in
`_bfd_mips_elf_symbol_processing', and two other ones to adjust DWARF-2
records as they're processed.  The ISA bit is set in each address
handled according to information retrieved from the symbol table for the
symbol spanning the address if any; limits are adjusted based on the
address they point to related to the respective base address.
Additionally minimal symbol information has to be adjusted accordingly
in its gdbarch hook.

With these changes in place some complications with ISA bit juggling in
the PC that never fully worked can be removed from the MIPS backend.
Conversely, the generic dynamic linker event special breakpoint symbol
handler has to be updated to call the minimal symbol gdbarch hook to
record that the symbol is a MIPS16 or microMIPS address if applicable or
the breakpoint will be set at the wrong address and either fail to work
or cause SIGTRAPs (this is because the symbol is handled early on and
bypasses regular symbol processing).

4. Results obtained

The change fixes the example above -- to repeat only the crucial steps:

(gdb) break main
Breakpoint 1 at 0x400491: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar

Breakpoint 1, main () at foobar.c:23
23        return foop ();
(gdb) print foo
$1 = {int (void)} 0x400681 <foo>
(gdb) set foop = bar
(gdb) advance bar
bar () at foobar.c:9
9       }
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068d <+0>:     jr      ra
   0x0040068f <+2>:     li      v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0  bar () at foobar.c:9
main () at foobar.c:24
24      }
Value returned is $2 = 2
(gdb) continue
Continuing.
[Inferior 1 (process 14128) exited with code 02]
(gdb)

-- excellent!

The change removes about 90 failures per MIPS16 multilib in mips-sde-elf
testing too, results for MIPS16 are now similar to that for standard
MIPS; microMIPS results are a bit worse because of host-I/O problems in
QEMU used instead of MIPSsim for microMIPS testing only:

                === gdb Summary ===

# of expected passes            14299
# of unexpected failures        187
# of expected failures          56
# of known failures             58
# of unresolved testcases       11
# of untested testcases         52
# of unsupported tests          174

MIPS16:

                === gdb Summary ===

# of expected passes            14298
# of unexpected failures        187
# of unexpected successes       2
# of expected failures          54
# of known failures             58
# of unresolved testcases       12
# of untested testcases         52
# of unsupported tests          174

microMIPS:

                === gdb Summary ===

# of expected passes            14149
# of unexpected failures        201
# of unexpected successes       2
# of expected failures          54
# of known failures             58
# of unresolved testcases       7
# of untested testcases         53
# of unsupported tests          175

2014-12-12  Maciej W. Rozycki  <macro@codesourcery.com>
            Maciej W. Rozycki  <macro@mips.com>
            Pedro Alves  <pedro@codesourcery.com>

	gdb/
	* gdbarch.sh (elf_make_msymbol_special): Change type to `F',
	remove `predefault' and `invalid_p' initializers.
	(make_symbol_special): New architecture method.
	(adjust_dwarf2_addr, adjust_dwarf2_line): Likewise.
	(objfile, symbol): New declarations.
	* arch-utils.h (default_elf_make_msymbol_special): Remove
	prototype.
	(default_make_symbol_special): New prototype.
	(default_adjust_dwarf2_addr): Likewise.
	(default_adjust_dwarf2_line): Likewise.
	* mips-tdep.h (mips_unmake_compact_addr): New prototype.
	* arch-utils.c (default_elf_make_msymbol_special): Remove
	function.
	(default_make_symbol_special): New function.
	(default_adjust_dwarf2_addr): Likewise.
	(default_adjust_dwarf2_line): Likewise.
	* dwarf2-frame.c (decode_frame_entry_1): Call
	`gdbarch_adjust_dwarf2_addr'.
	* dwarf2loc.c (dwarf2_find_location_expression): Likewise.
	* dwarf2read.c (create_addrmap_from_index): Likewise.
	(process_psymtab_comp_unit_reader): Likewise.
	(add_partial_symbol): Likewise.
	(add_partial_subprogram): Likewise.
	(process_full_comp_unit): Likewise.
	(read_file_scope): Likewise.
	(read_func_scope): Likewise.  Call `gdbarch_make_symbol_special'.
	(read_lexical_block_scope): Call `gdbarch_adjust_dwarf2_addr'.
	(read_call_site_scope): Likewise.
	(dwarf2_ranges_read): Likewise.
	(dwarf2_record_block_ranges): Likewise.
	(read_attribute_value): Likewise.
	(dwarf_decode_lines_1): Call `gdbarch_adjust_dwarf2_line'.
	(new_symbol_full): Call `gdbarch_adjust_dwarf2_addr'.
	* elfread.c (elf_symtab_read): Don't call
	`gdbarch_elf_make_msymbol_special' if unset.
	* mips-linux-tdep.c (micromips_linux_sigframe_validate): Strip
	the ISA bit from the PC.
	* mips-tdep.c (mips_unmake_compact_addr): New function.
	(mips_elf_make_msymbol_special): Set the ISA bit in the symbol's
	address appropriately.
	(mips_make_symbol_special): New function.
	(mips_pc_is_mips): Set the ISA bit before symbol lookup.
	(mips_pc_is_mips16): Likewise.
	(mips_pc_is_micromips): Likewise.
	(mips_pc_isa): Likewise.
	(mips_adjust_dwarf2_addr): New function.
	(mips_adjust_dwarf2_line): Likewise.
	(mips_read_pc, mips_unwind_pc): Keep the ISA bit.
	(mips_addr_bits_remove): Likewise.
	(mips_skip_trampoline_code): Likewise.
	(mips_write_pc): Don't set the ISA bit.
	(mips_eabi_push_dummy_call): Likewise.
	(mips_o64_push_dummy_call): Likewise.
	(mips_gdbarch_init): Install `mips_make_symbol_special',
	`mips_adjust_dwarf2_addr' and `mips_adjust_dwarf2_line' gdbarch
	handlers.
	* solib.c (gdb_bfd_lookup_symbol_from_symtab): Get
	target-specific symbol address adjustments.
	* gdbarch.h: Regenerate.
	* gdbarch.c: Regenerate.

2014-12-12  Maciej W. Rozycki  <macro@codesourcery.com>

	gdb/testsuite/
	* gdb.base/func-ptrs.c: New file.
	* gdb.base/func-ptrs.exp: New file.

17 files changed, 687 insertions, 133 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index bf1f80b..1dc180a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,68 @@
+2014-12-12  Maciej W. Rozycki  <macro@codesourcery.com>
+            Maciej W. Rozycki  <macro@mips.com>
+            Pedro Alves  <pedro@codesourcery.com>
+
+	* gdbarch.sh (elf_make_msymbol_special): Change type to `F',
+	remove `predefault' and `invalid_p' initializers.
+	(make_symbol_special): New architecture method.
+	(adjust_dwarf2_addr, adjust_dwarf2_line): Likewise.
+	(objfile, symbol): New declarations.
+	* arch-utils.h (default_elf_make_msymbol_special): Remove
+	prototype.
+	(default_make_symbol_special): New prototype.
+	(default_adjust_dwarf2_addr): Likewise.
+	(default_adjust_dwarf2_line): Likewise.
+	* mips-tdep.h (mips_unmake_compact_addr): New prototype.
+	* arch-utils.c (default_elf_make_msymbol_special): Remove
+	function.
+	(default_make_symbol_special): New function.
+	(default_adjust_dwarf2_addr): Likewise.
+	(default_adjust_dwarf2_line): Likewise.
+	* dwarf2-frame.c (decode_frame_entry_1): Call
+	`gdbarch_adjust_dwarf2_addr'.
+	* dwarf2loc.c (dwarf2_find_location_expression): Likewise.
+	* dwarf2read.c (create_addrmap_from_index): Likewise.
+	(process_psymtab_comp_unit_reader): Likewise.
+	(add_partial_symbol): Likewise.
+	(add_partial_subprogram): Likewise.
+	(process_full_comp_unit): Likewise.
+	(read_file_scope): Likewise.
+	(read_func_scope): Likewise.  Call `gdbarch_make_symbol_special'.
+	(read_lexical_block_scope): Call `gdbarch_adjust_dwarf2_addr'.
+	(read_call_site_scope): Likewise.
+	(dwarf2_ranges_read): Likewise.
+	(dwarf2_record_block_ranges): Likewise.
+	(read_attribute_value): Likewise.
+	(dwarf_decode_lines_1): Call `gdbarch_adjust_dwarf2_line'.
+	(new_symbol_full): Call `gdbarch_adjust_dwarf2_addr'.
+	* elfread.c (elf_symtab_read): Don't call
+	`gdbarch_elf_make_msymbol_special' if unset.
+	* mips-linux-tdep.c (micromips_linux_sigframe_validate): Strip
+	the ISA bit from the PC.
+	* mips-tdep.c (mips_unmake_compact_addr): New function.
+	(mips_elf_make_msymbol_special): Set the ISA bit in the symbol's
+	address appropriately.
+	(mips_make_symbol_special): New function.
+	(mips_pc_is_mips): Set the ISA bit before symbol lookup.
+	(mips_pc_is_mips16): Likewise.
+	(mips_pc_is_micromips): Likewise.
+	(mips_pc_isa): Likewise.
+	(mips_adjust_dwarf2_addr): New function.
+	(mips_adjust_dwarf2_line): Likewise.
+	(mips_read_pc, mips_unwind_pc): Keep the ISA bit.
+	(mips_addr_bits_remove): Likewise.
+	(mips_skip_trampoline_code): Likewise.
+	(mips_write_pc): Don't set the ISA bit.
+	(mips_eabi_push_dummy_call): Likewise.
+	(mips_o64_push_dummy_call): Likewise.
+	(mips_gdbarch_init): Install `mips_make_symbol_special',
+	`mips_adjust_dwarf2_addr' and `mips_adjust_dwarf2_line' gdbarch
+	handlers.
+	* solib.c (gdb_bfd_lookup_symbol_from_symtab): Get
+	target-specific symbol address adjustments.
+	* gdbarch.h: Regenerate.
+	* gdbarch.c: Regenerate.
+
 2014-12-12  Yao Qi  <yao@codesourcery.com>
 
 	PR tdep/14261
diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index a2e76de..33d5543 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -31,6 +31,7 @@
 #include "target-descriptions.h"
 #include "objfiles.h"
 #include "language.h"
+#include "symtab.h"
 
 #include "version.h"
 
@@ -167,17 +168,35 @@ no_op_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 }
 
 void
-default_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym)
+default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)
 {
   return;
 }
 
+/* See arch-utils.h.  */
+
 void
-default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)
+default_make_symbol_special (struct symbol *sym, struct objfile *objfile)
 {
   return;
 }
 
+/* See arch-utils.h.  */
+
+CORE_ADDR
+default_adjust_dwarf2_addr (CORE_ADDR pc)
+{
+  return pc;
+}
+
+/* See arch-utils.h.  */
+
+CORE_ADDR
+default_adjust_dwarf2_line (CORE_ADDR addr, int rel)
+{
+  return addr;
+}
+
 int
 cannot_register_not (struct gdbarch *gdbarch, int regnum)
 {
diff --git a/gdb/arch-utils.h b/gdb/arch-utils.h
index 1f5dd55..11e68e2 100644
--- a/gdb/arch-utils.h
+++ b/gdb/arch-utils.h
@@ -68,15 +68,22 @@ extern gdbarch_convert_from_func_ptr_addr_ftype convert_from_func_ptr_addr_ident
 
 extern int no_op_reg_to_regnum (struct gdbarch *gdbarch, int reg);
 
-/* Do nothing version of elf_make_msymbol_special.  */
-
-void default_elf_make_msymbol_special (asymbol *sym,
-				       struct minimal_symbol *msym);
-
 /* Do nothing version of coff_make_msymbol_special.  */
 
 void default_coff_make_msymbol_special (int val, struct minimal_symbol *msym);
 
+/* Do nothing default implementation of gdbarch_make_symbol_special.  */
+
+void default_make_symbol_special (struct symbol *sym, struct objfile *objfile);
+
+/* Do nothing default implementation of gdbarch_adjust_dwarf2_addr.  */
+
+CORE_ADDR default_adjust_dwarf2_addr (CORE_ADDR pc);
+
+/* Do nothing default implementation of gdbarch_adjust_dwarf2_line.  */
+
+CORE_ADDR default_adjust_dwarf2_line (CORE_ADDR addr, int rel);
+
 /* Version of cannot_fetch_register() / cannot_store_register() that
    always fails.  */
 
diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index 586f134..8747f4c 100644
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -2066,6 +2066,7 @@ decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
     {
       /* This is a FDE.  */
       struct dwarf2_fde *fde;
+      CORE_ADDR addr;
 
       /* Check that an FDE was expected.  */
       if ((entry_type & EH_FDE_TYPE_ID) == 0)
@@ -2099,14 +2100,16 @@ decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
 
       gdb_assert (fde->cie != NULL);
 
-      fde->initial_location =
-	read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
-			    buf, &bytes_read, 0);
+      addr = read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
+				 buf, &bytes_read, 0);
+      fde->initial_location = gdbarch_adjust_dwarf2_addr (gdbarch, addr);
       buf += bytes_read;
 
       fde->address_range =
 	read_encoded_value (unit, fde->cie->encoding & 0x0f,
 			    fde->cie->ptr_size, buf, &bytes_read, 0);
+      addr = gdbarch_adjust_dwarf2_addr (gdbarch, addr + fde->address_range);
+      fde->address_range = addr - fde->initial_location;
       buf += bytes_read;
 
       /* A 'z' augmentation in the CIE implies the presence of an
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 6e461bc..fbaa7d3 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -4296,6 +4296,9 @@ loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
       low += base_address;
       high += base_address;
 
+      low = gdbarch_adjust_dwarf2_addr (gdbarch, low);
+      high = gdbarch_adjust_dwarf2_addr (gdbarch, high);
+
       length = extract_unsigned_integer (loc_ptr, 2, byte_order);
       loc_ptr += 2;
 
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 829611d..e36af5a 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -2824,6 +2824,7 @@ create_signatured_type_table_from_index (struct objfile *objfile,
 static void
 create_addrmap_from_index (struct objfile *objfile, struct mapped_index *index)
 {
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   const gdb_byte *iter, *end;
   struct obstack temp_obstack;
   struct addrmap *mutable_map;
@@ -2865,8 +2866,9 @@ create_addrmap_from_index (struct objfile *objfile, struct mapped_index *index)
 	  continue;
 	}
 
-      addrmap_set_empty (mutable_map, lo + baseaddr, hi + baseaddr - 1,
-			 dw2_get_cutu (cu_index));
+      lo = gdbarch_adjust_dwarf2_addr (gdbarch, lo + baseaddr);
+      hi = gdbarch_adjust_dwarf2_addr (gdbarch, hi + baseaddr);
+      addrmap_set_empty (mutable_map, lo, hi - 1, dw2_get_cutu (cu_index));
     }
 
   objfile->psymtabs_addrmap = addrmap_create_fixed (mutable_map,
@@ -5849,6 +5851,7 @@ process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,
 {
   struct dwarf2_cu *cu = reader->cu;
   struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   struct dwarf2_per_cu_data *per_cu = cu->per_cu;
   struct attribute *attr;
   CORE_ADDR baseaddr;
@@ -5893,8 +5896,11 @@ process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,
     /* Store the contiguous range if it is not empty; it can be empty for
        CUs with no code.  */
     addrmap_set_empty (objfile->psymtabs_addrmap,
-		       best_lowpc + baseaddr,
-		       best_highpc + baseaddr - 1, pst);
+		       gdbarch_adjust_dwarf2_addr (gdbarch,
+						   best_lowpc + baseaddr),
+		       gdbarch_adjust_dwarf2_addr (gdbarch,
+						   best_highpc + baseaddr) - 1,
+		       pst);
 
   /* Check if comp unit has_children.
      If so, read the rest of the partial symbols from this comp unit.
@@ -5925,8 +5931,8 @@ process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,
 	  best_highpc = highpc;
 	}
     }
-  pst->textlow = best_lowpc + baseaddr;
-  pst->texthigh = best_highpc + baseaddr;
+  pst->textlow = gdbarch_adjust_dwarf2_addr (gdbarch, best_lowpc + baseaddr);
+  pst->texthigh = gdbarch_adjust_dwarf2_addr (gdbarch, best_highpc + baseaddr);
 
   pst->n_global_syms = objfile->global_psymbols.next -
     (objfile->global_psymbols.list + pst->globals_offset);
@@ -6789,6 +6795,7 @@ static void
 add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
 {
   struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   CORE_ADDR addr = 0;
   const char *actual_name = NULL;
   CORE_ADDR baseaddr;
@@ -6806,31 +6813,30 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
   switch (pdi->tag)
     {
     case DW_TAG_subprogram:
+      addr = gdbarch_adjust_dwarf2_addr (gdbarch, pdi->lowpc + baseaddr);
       if (pdi->is_external || cu->language == language_ada)
 	{
           /* brobecker/2007-12-26: Normally, only "external" DIEs are part
              of the global scope.  But in Ada, we want to be able to access
              nested procedures globally.  So all Ada subprograms are stored
              in the global scope.  */
-	  /* prim_record_minimal_symbol (actual_name, pdi->lowpc + baseaddr,
-	     mst_text, objfile); */
+	  /* prim_record_minimal_symbol (actual_name, addr, mst_text,
+	     objfile); */
 	  add_psymbol_to_list (actual_name, strlen (actual_name),
 			       built_actual_name != NULL,
 			       VAR_DOMAIN, LOC_BLOCK,
 			       &objfile->global_psymbols,
-			       0, pdi->lowpc + baseaddr,
-			       cu->language, objfile);
+			       0, addr, cu->language, objfile);
 	}
       else
 	{
-	  /* prim_record_minimal_symbol (actual_name, pdi->lowpc + baseaddr,
-	     mst_file_text, objfile); */
+	  /* prim_record_minimal_symbol (actual_name, addr, mst_file_text,
+	     objfile); */
 	  add_psymbol_to_list (actual_name, strlen (actual_name),
 			       built_actual_name != NULL,
 			       VAR_DOMAIN, LOC_BLOCK,
 			       &objfile->static_psymbols,
-			       0, pdi->lowpc + baseaddr,
-			       cu->language, objfile);
+			       0, addr, cu->language, objfile);
 	}
       break;
     case DW_TAG_constant:
@@ -7031,14 +7037,19 @@ add_partial_subprogram (struct partial_die_info *pdi,
             *highpc = pdi->highpc;
 	  if (set_addrmap)
 	    {
-	      CORE_ADDR baseaddr;
 	      struct objfile *objfile = cu->objfile;
+	      struct gdbarch *gdbarch = get_objfile_arch (objfile);
+	      CORE_ADDR baseaddr;
+	      CORE_ADDR highpc;
+	      CORE_ADDR lowpc;
 
 	      baseaddr = ANOFFSET (objfile->section_offsets,
 				   SECT_OFF_TEXT (objfile));
-	      addrmap_set_empty (objfile->psymtabs_addrmap,
-				 pdi->lowpc + baseaddr,
-				 pdi->highpc - 1 + baseaddr,
+	      lowpc = gdbarch_adjust_dwarf2_addr (gdbarch,
+						  pdi->lowpc + baseaddr);
+	      highpc = gdbarch_adjust_dwarf2_addr (gdbarch,
+						   pdi->highpc + baseaddr);
+	      addrmap_set_empty (objfile->psymtabs_addrmap, lowpc, highpc - 1,
 				 cu->per_cu->v.psymtab);
 	    }
         }
@@ -7925,11 +7936,13 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
 {
   struct dwarf2_cu *cu = per_cu->cu;
   struct objfile *objfile = per_cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   CORE_ADDR lowpc, highpc;
   struct compunit_symtab *cust;
   struct cleanup *back_to, *delayed_list_cleanup;
   CORE_ADDR baseaddr;
   struct block *static_block;
+  CORE_ADDR addr;
 
   baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
 
@@ -7960,8 +7973,8 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
      it, by scanning the DIE's below the compilation unit.  */
   get_scope_pc_bounds (cu->dies, &lowpc, &highpc, cu);
 
-  static_block
-    = end_symtab_get_static_block (highpc + baseaddr, 0, 1);
+  addr = gdbarch_adjust_dwarf2_addr (gdbarch, highpc + baseaddr);
+  static_block = end_symtab_get_static_block (addr, 0, 1);
 
   /* If the comp unit has DW_AT_ranges, it may have discontiguous ranges.
      Also, DW_AT_ranges may record ranges not belonging to any child DIEs
@@ -9006,6 +9019,7 @@ static void
 read_file_scope (struct die_info *die, struct dwarf2_cu *cu)
 {
   struct objfile *objfile = dwarf2_per_objfile->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   struct cleanup *back_to = make_cleanup (null_cleanup, 0);
   CORE_ADDR lowpc = ((CORE_ADDR) -1);
   CORE_ADDR highpc = ((CORE_ADDR) 0);
@@ -9024,8 +9038,7 @@ read_file_scope (struct die_info *die, struct dwarf2_cu *cu)
      from finish_block.  */
   if (lowpc == ((CORE_ADDR) -1))
     lowpc = highpc;
-  lowpc += baseaddr;
-  highpc += baseaddr;
+  lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
 
   find_file_and_directory (die, cu, &name, &comp_dir);
 
@@ -11133,6 +11146,7 @@ static void
 read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
 {
   struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   struct context_stack *new;
   CORE_ADDR lowpc;
   CORE_ADDR highpc;
@@ -11185,8 +11199,8 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
       return;
     }
 
-  lowpc += baseaddr;
-  highpc += baseaddr;
+  lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
+  highpc = gdbarch_adjust_dwarf2_addr (gdbarch, highpc + baseaddr);
 
   /* If we have any template arguments, then we must allocate a
      different sort of symbol.  */
@@ -11273,6 +11287,8 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
   /* If we have address ranges, record them.  */
   dwarf2_record_block_ranges (die, block, baseaddr, cu);
 
+  gdbarch_make_symbol_special (gdbarch, new->name, objfile);
+
   /* Attach template arguments to function.  */
   if (! VEC_empty (symbolp, template_args))
     {
@@ -11309,6 +11325,7 @@ static void
 read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)
 {
   struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   struct context_stack *new;
   CORE_ADDR lowpc, highpc;
   struct die_info *child_die;
@@ -11323,8 +11340,8 @@ read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)
      describe ranges.  */
   if (!dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))
     return;
-  lowpc += baseaddr;
-  highpc += baseaddr;
+  lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
+  highpc = gdbarch_adjust_dwarf2_addr (gdbarch, highpc + baseaddr);
 
   push_context (0, lowpc);
   if (die->child != NULL)
@@ -11386,6 +11403,7 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
       return;
     }
   pc = attr_value_as_address (attr) + baseaddr;
+  pc = gdbarch_adjust_dwarf2_addr (gdbarch, pc);
 
   if (cu->call_site_htab == NULL)
     cu->call_site_htab = htab_create_alloc_ex (16, core_addr_hash, core_addr_eq,
@@ -11534,7 +11552,10 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
 		         "low pc, for referencing DIE 0x%x [in module %s]"),
 		       die->offset.sect_off, objfile_name (objfile));
 	  else
-	    SET_FIELD_PHYSADDR (call_site->target, lowpc + baseaddr);
+	    {
+	      lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
+	      SET_FIELD_PHYSADDR (call_site->target, lowpc);
+	    }
 	}
     }
   else
@@ -11662,6 +11683,7 @@ dwarf2_ranges_read (unsigned offset, CORE_ADDR *low_return,
 		    struct partial_symtab *ranges_pst)
 {
   struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   struct comp_unit_head *cu_header = &cu->header;
   bfd *obfd = objfile->obfd;
   unsigned int addr_size = cu_header->addr_size;
@@ -11769,10 +11791,17 @@ dwarf2_ranges_read (unsigned offset, CORE_ADDR *low_return,
 	}
 
       if (ranges_pst != NULL)
-	addrmap_set_empty (objfile->psymtabs_addrmap,
-			   range_beginning + baseaddr,
-			   range_end - 1 + baseaddr,
-			   ranges_pst);
+	{
+	  CORE_ADDR lowpc;
+	  CORE_ADDR highpc;
+
+	  lowpc = gdbarch_adjust_dwarf2_addr (gdbarch,
+					      range_beginning + baseaddr);
+	  highpc = gdbarch_adjust_dwarf2_addr (gdbarch,
+					       range_end + baseaddr);
+	  addrmap_set_empty (objfile->psymtabs_addrmap, lowpc, highpc - 1,
+			     ranges_pst);
+	}
 
       /* FIXME: This is recording everything as a low-high
 	 segment of consecutive addresses.  We should have a
@@ -11986,6 +12015,7 @@ dwarf2_record_block_ranges (struct die_info *die, struct block *block,
                             CORE_ADDR baseaddr, struct dwarf2_cu *cu)
 {
   struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   struct attribute *attr;
   struct attribute *attr_high;
 
@@ -12001,7 +12031,9 @@ dwarf2_record_block_ranges (struct die_info *die, struct block *block,
 	  if (cu->header.version >= 4 && attr_form_is_constant (attr_high))
 	    high += low;
 
-          record_block_range (block, baseaddr + low, baseaddr + high - 1);
+	  low = gdbarch_adjust_dwarf2_addr (gdbarch, low + baseaddr);
+	  high = gdbarch_adjust_dwarf2_addr (gdbarch, high + baseaddr);
+	  record_block_range (block, low, high - 1);
         }
     }
 
@@ -12105,6 +12137,8 @@ dwarf2_record_block_ranges (struct die_info *die, struct block *block,
 		  continue;
 		}
 
+	      start = gdbarch_adjust_dwarf2_addr (gdbarch, start);
+	      end = gdbarch_adjust_dwarf2_addr (gdbarch, end);
               record_block_range (block, start, end - 1);
             }
         }
@@ -15931,6 +15965,8 @@ read_attribute_value (const struct die_reader_specs *reader,
 		      const gdb_byte *info_ptr)
 {
   struct dwarf2_cu *cu = reader->cu;
+  struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   bfd *abfd = reader->abfd;
   struct comp_unit_head *cu_header = &cu->header;
   unsigned int bytes_read;
@@ -15953,6 +15989,7 @@ read_attribute_value (const struct die_reader_specs *reader,
       break;
     case DW_FORM_addr:
       DW_ADDR (attr) = read_address (abfd, info_ptr, cu, &bytes_read);
+      DW_ADDR (attr) = gdbarch_adjust_dwarf2_addr (gdbarch, DW_ADDR (attr));
       info_ptr += bytes_read;
       break;
     case DW_FORM_block2:
@@ -17284,8 +17321,12 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
   /* Read the statement sequences until there's nothing left.  */
   while (line_ptr < line_end)
     {
-      /* state machine registers  */
-      CORE_ADDR address = 0;
+      /* State machine registers.  Call `gdbarch_adjust_dwarf2_line'
+         on the initial 0 address as if there was a line entry for it
+         so that the backend has a chance to adjust it and also record
+         it in case it needs it.  This is currently used by MIPS code,
+         cf. `mips_adjust_dwarf2_line'.  */
+      CORE_ADDR address = gdbarch_adjust_dwarf2_line (gdbarch, 0, 0);
       unsigned int file = 1;
       unsigned int line = 1;
       int is_stmt = lh->default_is_stmt;
@@ -17328,12 +17369,14 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
 	    {
 	      /* Special opcode.  */
 	      unsigned char adj_opcode;
+	      CORE_ADDR addr_adj;
 	      int line_delta;
 
 	      adj_opcode = op_code - lh->opcode_base;
-	      address += (((op_index + (adj_opcode / lh->line_range))
+	      addr_adj = (((op_index + (adj_opcode / lh->line_range))
 			   / lh->maximum_ops_per_instruction)
 			  * lh->minimum_instruction_length);
+	      address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
 	      op_index = ((op_index + (adj_opcode / lh->line_range))
 			  % lh->maximum_ops_per_instruction);
 	      line_delta = lh->line_base + (adj_opcode % lh->line_range);
@@ -17410,6 +17453,7 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
 		  op_index = 0;
 		  line_ptr += bytes_read;
 		  address += baseaddr;
+		  address = gdbarch_adjust_dwarf2_line (gdbarch, address, 0);
 		  break;
 		case DW_LNE_define_file:
                   {
@@ -17487,10 +17531,12 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
 	      {
 		CORE_ADDR adjust
 		  = read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
+		CORE_ADDR addr_adj;
 
-		address += (((op_index + adjust)
+		addr_adj = (((op_index + adjust)
 			     / lh->maximum_ops_per_instruction)
 			    * lh->minimum_instruction_length);
+		address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
 		op_index = ((op_index + adjust)
 			    % lh->maximum_ops_per_instruction);
 		line_ptr += bytes_read;
@@ -17550,18 +17596,25 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
 	    case DW_LNS_const_add_pc:
 	      {
 		CORE_ADDR adjust = (255 - lh->opcode_base) / lh->line_range;
+		CORE_ADDR addr_adj;
 
-		address += (((op_index + adjust)
+		addr_adj = (((op_index + adjust)
 			     / lh->maximum_ops_per_instruction)
 			    * lh->minimum_instruction_length);
+		address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
 		op_index = ((op_index + adjust)
 			    % lh->maximum_ops_per_instruction);
 	      }
 	      break;
 	    case DW_LNS_fixed_advance_pc:
-	      address += read_2_bytes (abfd, line_ptr);
-	      op_index = 0;
-	      line_ptr += 2;
+	      {
+		CORE_ADDR addr_adj;
+
+		addr_adj = read_2_bytes (abfd, line_ptr);
+		address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
+		op_index = 0;
+		line_ptr += 2;
+	      }
 	      break;
 	    default:
 	      {
@@ -17813,6 +17866,7 @@ new_symbol_full (struct die_info *die, struct type *type, struct dwarf2_cu *cu,
 		 struct symbol *space)
 {
   struct objfile *objfile = cu->objfile;
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
   struct symbol *sym = NULL;
   const char *name;
   struct attribute *attr = NULL;
@@ -17890,8 +17944,13 @@ new_symbol_full (struct die_info *die, struct type *type, struct dwarf2_cu *cu,
 	case DW_TAG_label:
 	  attr = dwarf2_attr (die, DW_AT_low_pc, cu);
 	  if (attr)
-	    SYMBOL_VALUE_ADDRESS (sym)
-	      = attr_value_as_address (attr) + baseaddr;
+	    {
+	      CORE_ADDR addr;
+
+	      addr = attr_value_as_address (attr);
+	      addr = gdbarch_adjust_dwarf2_addr (gdbarch, addr + baseaddr);
+	      SYMBOL_VALUE_ADDRESS (sym) = addr;
+	    }
 	  SYMBOL_TYPE (sym) = objfile_type (objfile)->builtin_core_addr;
 	  SYMBOL_DOMAIN (sym) = LABEL_DOMAIN;
 	  SYMBOL_ACLASS_INDEX (sym) = LOC_LABEL;
diff --git a/gdb/elfread.c b/gdb/elfread.c
index 19aaed3..b4ec067 100644
--- a/gdb/elfread.c
+++ b/gdb/elfread.c
@@ -247,6 +247,8 @@ elf_symtab_read (struct objfile *objfile, int type,
   const char *filesymname = "";
   struct dbx_symfile_info *dbx = DBX_SYMFILE_INFO (objfile);
   int stripped = (bfd_get_symcount (objfile->obfd) == 0);
+  int elf_make_msymbol_special_p
+    = gdbarch_elf_make_msymbol_special_p (gdbarch);
 
   for (i = 0; i < number_of_symbols; i++)
     {
@@ -330,7 +332,8 @@ elf_symtab_read (struct objfile *objfile, int type,
 	  if (msym != NULL)
 	    {
 	      msym->filename = filesymname;
-	      gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
+	      if (elf_make_msymbol_special_p)
+		gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
 	    }
 	  continue;
 	}
@@ -558,7 +561,8 @@ elf_symtab_read (struct objfile *objfile, int type,
 		}
 
 	      msym->filename = filesymname;
-	      gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
+	      if (elf_make_msymbol_special_p)
+		gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
 	    }
 
 	  /* If we see a default versioned symbol, install it under
@@ -597,7 +601,9 @@ elf_symtab_read (struct objfile *objfile, int type,
 		      SET_MSYMBOL_SIZE (mtramp, MSYMBOL_SIZE (msym));
 		      mtramp->created_by_gdb = 1;
 		      mtramp->filename = filesymname;
-		      gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp);
+		      if (elf_make_msymbol_special_p)
+			gdbarch_elf_make_msymbol_special (gdbarch,
+							  sym, mtramp);
 		    }
 		}
 	    }
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index f89a6d2..132fff3 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -252,6 +252,9 @@ struct gdbarch
   gdbarch_in_function_epilogue_p_ftype *in_function_epilogue_p;
   gdbarch_elf_make_msymbol_special_ftype *elf_make_msymbol_special;
   gdbarch_coff_make_msymbol_special_ftype *coff_make_msymbol_special;
+  gdbarch_make_symbol_special_ftype *make_symbol_special;
+  gdbarch_adjust_dwarf2_addr_ftype *adjust_dwarf2_addr;
+  gdbarch_adjust_dwarf2_line_ftype *adjust_dwarf2_line;
   int cannot_step_breakpoint;
   int have_nonsteppable_watchpoint;
   gdbarch_address_class_type_flags_ftype *address_class_type_flags;
@@ -392,8 +395,10 @@ gdbarch_alloc (const struct gdbarch_info *info,
   gdbarch->skip_solib_resolver = generic_skip_solib_resolver;
   gdbarch->in_solib_return_trampoline = generic_in_solib_return_trampoline;
   gdbarch->in_function_epilogue_p = generic_in_function_epilogue_p;
-  gdbarch->elf_make_msymbol_special = default_elf_make_msymbol_special;
   gdbarch->coff_make_msymbol_special = default_coff_make_msymbol_special;
+  gdbarch->make_symbol_special = default_make_symbol_special;
+  gdbarch->adjust_dwarf2_addr = default_adjust_dwarf2_addr;
+  gdbarch->adjust_dwarf2_line = default_adjust_dwarf2_line;
   gdbarch->register_reggroup_p = default_register_reggroup_p;
   gdbarch->skip_permanent_breakpoint = default_skip_permanent_breakpoint;
   gdbarch->displaced_step_hw_singlestep = default_displaced_step_hw_singlestep;
@@ -565,8 +570,11 @@ verify_gdbarch (struct gdbarch *gdbarch)
   /* Skip verify of skip_solib_resolver, invalid_p == 0 */
   /* Skip verify of in_solib_return_trampoline, invalid_p == 0 */
   /* Skip verify of in_function_epilogue_p, invalid_p == 0 */
-  /* Skip verify of elf_make_msymbol_special, invalid_p == 0 */
+  /* Skip verify of elf_make_msymbol_special, has predicate.  */
   /* Skip verify of coff_make_msymbol_special, invalid_p == 0 */
+  /* Skip verify of make_symbol_special, invalid_p == 0 */
+  /* Skip verify of adjust_dwarf2_addr, invalid_p == 0 */
+  /* Skip verify of adjust_dwarf2_line, invalid_p == 0 */
   /* Skip verify of cannot_step_breakpoint, invalid_p == 0 */
   /* Skip verify of have_nonsteppable_watchpoint, invalid_p == 0 */
   /* Skip verify of address_class_type_flags, has predicate.  */
@@ -691,6 +699,12 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
                       "gdbarch_dump: adjust_breakpoint_address = <%s>\n",
                       host_address_to_string (gdbarch->adjust_breakpoint_address));
   fprintf_unfiltered (file,
+                      "gdbarch_dump: adjust_dwarf2_addr = <%s>\n",
+                      host_address_to_string (gdbarch->adjust_dwarf2_addr));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: adjust_dwarf2_line = <%s>\n",
+                      host_address_to_string (gdbarch->adjust_dwarf2_line));
+  fprintf_unfiltered (file,
                       "gdbarch_dump: auto_charset = <%s>\n",
                       host_address_to_string (gdbarch->auto_charset));
   fprintf_unfiltered (file,
@@ -838,6 +852,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
                       "gdbarch_dump: ecoff_reg_to_regnum = <%s>\n",
                       host_address_to_string (gdbarch->ecoff_reg_to_regnum));
   fprintf_unfiltered (file,
+                      "gdbarch_dump: gdbarch_elf_make_msymbol_special_p() = %d\n",
+                      gdbarch_elf_make_msymbol_special_p (gdbarch));
+  fprintf_unfiltered (file,
                       "gdbarch_dump: elf_make_msymbol_special = <%s>\n",
                       host_address_to_string (gdbarch->elf_make_msymbol_special));
   fprintf_unfiltered (file,
@@ -1018,6 +1035,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
                       "gdbarch_dump: make_corefile_notes = <%s>\n",
                       host_address_to_string (gdbarch->make_corefile_notes));
   fprintf_unfiltered (file,
+                      "gdbarch_dump: make_symbol_special = <%s>\n",
+                      host_address_to_string (gdbarch->make_symbol_special));
+  fprintf_unfiltered (file,
                       "gdbarch_dump: gdbarch_max_insn_length_p() = %d\n",
                       gdbarch_max_insn_length_p (gdbarch));
   fprintf_unfiltered (file,
@@ -3065,6 +3085,13 @@ set_gdbarch_in_function_epilogue_p (struct gdbarch *gdbarch,
   gdbarch->in_function_epilogue_p = in_function_epilogue_p;
 }
 
+int
+gdbarch_elf_make_msymbol_special_p (struct gdbarch *gdbarch)
+{
+  gdb_assert (gdbarch != NULL);
+  return gdbarch->elf_make_msymbol_special != NULL;
+}
+
 void
 gdbarch_elf_make_msymbol_special (struct gdbarch *gdbarch, asymbol *sym, struct minimal_symbol *msym)
 {
@@ -3099,6 +3126,57 @@ set_gdbarch_coff_make_msymbol_special (struct gdbarch *gdbarch,
   gdbarch->coff_make_msymbol_special = coff_make_msymbol_special;
 }
 
+void
+gdbarch_make_symbol_special (struct gdbarch *gdbarch, struct symbol *sym, struct objfile *objfile)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->make_symbol_special != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_make_symbol_special called\n");
+  gdbarch->make_symbol_special (sym, objfile);
+}
+
+void
+set_gdbarch_make_symbol_special (struct gdbarch *gdbarch,
+                                 gdbarch_make_symbol_special_ftype make_symbol_special)
+{
+  gdbarch->make_symbol_special = make_symbol_special;
+}
+
+CORE_ADDR
+gdbarch_adjust_dwarf2_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->adjust_dwarf2_addr != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_adjust_dwarf2_addr called\n");
+  return gdbarch->adjust_dwarf2_addr (pc);
+}
+
+void
+set_gdbarch_adjust_dwarf2_addr (struct gdbarch *gdbarch,
+                                gdbarch_adjust_dwarf2_addr_ftype adjust_dwarf2_addr)
+{
+  gdbarch->adjust_dwarf2_addr = adjust_dwarf2_addr;
+}
+
+CORE_ADDR
+gdbarch_adjust_dwarf2_line (struct gdbarch *gdbarch, CORE_ADDR addr, int rel)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->adjust_dwarf2_line != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_adjust_dwarf2_line called\n");
+  return gdbarch->adjust_dwarf2_line (addr, rel);
+}
+
+void
+set_gdbarch_adjust_dwarf2_line (struct gdbarch *gdbarch,
+                                gdbarch_adjust_dwarf2_line_ftype adjust_dwarf2_line)
+{
+  gdbarch->adjust_dwarf2_line = adjust_dwarf2_line;
+}
+
 int
 gdbarch_cannot_step_breakpoint (struct gdbarch *gdbarch)
 {
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 0bd1d56..ba4fe62 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -51,6 +51,8 @@ struct target_ops;
 struct obstack;
 struct bp_target_info;
 struct target_desc;
+struct objfile;
+struct symbol;
 struct displaced_step_closure;
 struct core_regset_section;
 struct syscall;
@@ -688,6 +690,16 @@ typedef int (gdbarch_in_function_epilogue_p_ftype) (struct gdbarch *gdbarch, COR
 extern int gdbarch_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR addr);
 extern void set_gdbarch_in_function_epilogue_p (struct gdbarch *gdbarch, gdbarch_in_function_epilogue_p_ftype *in_function_epilogue_p);
 
+/* Process an ELF symbol in the minimal symbol table in a backend-specific
+   way.  Normally this hook is supposed to do nothing, however if required,
+   then this hook can be used to apply tranformations to symbols that are
+   considered special in some way.  For example the MIPS backend uses it
+   to interpret `st_other' information to mark compressed code symbols so
+   that they can be treated in the appropriate manner in the processing of
+   the main symbol table and DWARF-2 records. */
+
+extern int gdbarch_elf_make_msymbol_special_p (struct gdbarch *gdbarch);
+
 typedef void (gdbarch_elf_make_msymbol_special_ftype) (asymbol *sym, struct minimal_symbol *msym);
 extern void gdbarch_elf_make_msymbol_special (struct gdbarch *gdbarch, asymbol *sym, struct minimal_symbol *msym);
 extern void set_gdbarch_elf_make_msymbol_special (struct gdbarch *gdbarch, gdbarch_elf_make_msymbol_special_ftype *elf_make_msymbol_special);
@@ -696,6 +708,45 @@ typedef void (gdbarch_coff_make_msymbol_special_ftype) (int val, struct minimal_
 extern void gdbarch_coff_make_msymbol_special (struct gdbarch *gdbarch, int val, struct minimal_symbol *msym);
 extern void set_gdbarch_coff_make_msymbol_special (struct gdbarch *gdbarch, gdbarch_coff_make_msymbol_special_ftype *coff_make_msymbol_special);
 
+/* Process a symbol in the main symbol table in a backend-specific way.
+   Normally this hook is supposed to do nothing, however if required,
+   then this hook can be used to apply tranformations to symbols that
+   are considered special in some way.  This is currently used by the
+   MIPS backend to make sure compressed code symbols have the ISA bit
+   set.  This in turn is needed for symbol values seen in GDB to match
+   the values used at the runtime by the program itself, for function
+   and label references. */
+
+typedef void (gdbarch_make_symbol_special_ftype) (struct symbol *sym, struct objfile *objfile);
+extern void gdbarch_make_symbol_special (struct gdbarch *gdbarch, struct symbol *sym, struct objfile *objfile);
+extern void set_gdbarch_make_symbol_special (struct gdbarch *gdbarch, gdbarch_make_symbol_special_ftype *make_symbol_special);
+
+/* Adjust the address retrieved from a DWARF-2 record other than a line
+   entry in a backend-specific way.  Normally this hook is supposed to
+   return the address passed unchanged, however if that is incorrect for
+   any reason, then this hook can be used to fix the address up in the
+   required manner.  This is currently used by the MIPS backend to make
+   sure addresses in FDE, range records, etc. referring to compressed
+   code have the ISA bit set, matching line information and the symbol
+   table. */
+
+typedef CORE_ADDR (gdbarch_adjust_dwarf2_addr_ftype) (CORE_ADDR pc);
+extern CORE_ADDR gdbarch_adjust_dwarf2_addr (struct gdbarch *gdbarch, CORE_ADDR pc);
+extern void set_gdbarch_adjust_dwarf2_addr (struct gdbarch *gdbarch, gdbarch_adjust_dwarf2_addr_ftype *adjust_dwarf2_addr);
+
+/* Adjust the address updated by a line entry in a backend-specific way.
+   Normally this hook is supposed to return the address passed unchanged,
+   however in the case of inconsistencies in these records, this hook can
+   be used to fix them up in the required manner.  This is currently used
+   by the MIPS backend to make sure all line addresses in compressed code
+   are presented with the ISA bit set, which is not always the case.  This
+   in turn ensures breakpoint addresses are correctly matched against the
+   stop PC. */
+
+typedef CORE_ADDR (gdbarch_adjust_dwarf2_line_ftype) (CORE_ADDR addr, int rel);
+extern CORE_ADDR gdbarch_adjust_dwarf2_line (struct gdbarch *gdbarch, CORE_ADDR addr, int rel);
+extern void set_gdbarch_adjust_dwarf2_line (struct gdbarch *gdbarch, gdbarch_adjust_dwarf2_line_ftype *adjust_dwarf2_line);
+
 extern int gdbarch_cannot_step_breakpoint (struct gdbarch *gdbarch);
 extern void set_gdbarch_cannot_step_breakpoint (struct gdbarch *gdbarch, int cannot_step_breakpoint);
 
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 8aeb394..25544e3 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -635,8 +635,42 @@ m:int:in_solib_return_trampoline:CORE_ADDR pc, const char *name:pc, name::generi
 # which don't suffer from that problem could just let this functionality
 # untouched.
 m:int:in_function_epilogue_p:CORE_ADDR addr:addr:0:generic_in_function_epilogue_p::0
-f:void:elf_make_msymbol_special:asymbol *sym, struct minimal_symbol *msym:sym, msym::default_elf_make_msymbol_special::0
+# Process an ELF symbol in the minimal symbol table in a backend-specific
+# way.  Normally this hook is supposed to do nothing, however if required,
+# then this hook can be used to apply tranformations to symbols that are
+# considered special in some way.  For example the MIPS backend uses it
+# to interpret \`st_other' information to mark compressed code symbols so
+# that they can be treated in the appropriate manner in the processing of
+# the main symbol table and DWARF-2 records.
+F:void:elf_make_msymbol_special:asymbol *sym, struct minimal_symbol *msym:sym, msym
 f:void:coff_make_msymbol_special:int val, struct minimal_symbol *msym:val, msym::default_coff_make_msymbol_special::0
+# Process a symbol in the main symbol table in a backend-specific way.
+# Normally this hook is supposed to do nothing, however if required,
+# then this hook can be used to apply tranformations to symbols that
+# are considered special in some way.  This is currently used by the
+# MIPS backend to make sure compressed code symbols have the ISA bit
+# set.  This in turn is needed for symbol values seen in GDB to match
+# the values used at the runtime by the program itself, for function
+# and label references.
+f:void:make_symbol_special:struct symbol *sym, struct objfile *objfile:sym, objfile::default_make_symbol_special::0
+# Adjust the address retrieved from a DWARF-2 record other than a line
+# entry in a backend-specific way.  Normally this hook is supposed to
+# return the address passed unchanged, however if that is incorrect for
+# any reason, then this hook can be used to fix the address up in the
+# required manner.  This is currently used by the MIPS backend to make
+# sure addresses in FDE, range records, etc. referring to compressed
+# code have the ISA bit set, matching line information and the symbol
+# table.
+f:CORE_ADDR:adjust_dwarf2_addr:CORE_ADDR pc:pc::default_adjust_dwarf2_addr::0
+# Adjust the address updated by a line entry in a backend-specific way.
+# Normally this hook is supposed to return the address passed unchanged,
+# however in the case of inconsistencies in these records, this hook can
+# be used to fix them up in the required manner.  This is currently used
+# by the MIPS backend to make sure all line addresses in compressed code
+# are presented with the ISA bit set, which is not always the case.  This
+# in turn ensures breakpoint addresses are correctly matched against the
+# stop PC.
+f:CORE_ADDR:adjust_dwarf2_line:CORE_ADDR addr, int rel:addr, rel::default_adjust_dwarf2_line::0
 v:int:cannot_step_breakpoint:::0:0::0
 v:int:have_nonsteppable_watchpoint:::0:0::0
 F:int:address_class_type_flags:int byte_size, int dwarf2_addr_class:byte_size, dwarf2_addr_class
@@ -1153,6 +1187,8 @@ struct target_ops;
 struct obstack;
 struct bp_target_info;
 struct target_desc;
+struct objfile;
+struct symbol;
 struct displaced_step_closure;
 struct core_regset_section;
 struct syscall;
diff --git a/gdb/mips-linux-tdep.c b/gdb/mips-linux-tdep.c
index 41602ba..243a671 100644
--- a/gdb/mips-linux-tdep.c
+++ b/gdb/mips-linux-tdep.c
@@ -1364,7 +1364,13 @@ micromips_linux_sigframe_validate (const struct tramp_frame *self,
 				   struct frame_info *this_frame,
 				   CORE_ADDR *pc)
 {
-  return mips_pc_is_micromips (get_frame_arch (this_frame), *pc);
+  if (mips_pc_is_micromips (get_frame_arch (this_frame), *pc))
+    {
+      *pc = mips_unmake_compact_addr (*pc);
+      return 1;
+    }
+  else
+    return 0;
 }
 
 /* Implement the "write_pc" gdbarch method.  */
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index c072bf0..5a5a716 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -340,6 +340,15 @@ make_compact_addr (CORE_ADDR addr)
   return ((addr) | (CORE_ADDR) 1);
 }
 
+/* Extern version of unmake_compact_addr; we use a separate function
+   so that unmake_compact_addr can be inlined throughout this file.  */
+
+CORE_ADDR
+mips_unmake_compact_addr (CORE_ADDR addr)
+{
+  return unmake_compact_addr (addr);
+}
+
 /* Functions for setting and testing a bit in a minimal symbol that
    marks it as MIPS16 or microMIPS function.  The MSB of the minimal
    symbol's "info" field is used for this purpose.
@@ -369,9 +378,15 @@ mips_elf_make_msymbol_special (asymbol * sym, struct minimal_symbol *msym)
     return;
 
   if (ELF_ST_IS_MICROMIPS (st_other))
-    MSYMBOL_TARGET_FLAG_2 (msym) = 1;
+    {
+      MSYMBOL_TARGET_FLAG_2 (msym) = 1;
+      SET_MSYMBOL_VALUE_ADDRESS (msym, MSYMBOL_VALUE_RAW_ADDRESS (msym) | 1);
+    }
   else if (ELF_ST_IS_MIPS16 (st_other))
-    MSYMBOL_TARGET_FLAG_1 (msym) = 1;
+    {
+      MSYMBOL_TARGET_FLAG_1 (msym) = 1;
+      SET_MSYMBOL_VALUE_ADDRESS (msym, MSYMBOL_VALUE_RAW_ADDRESS (msym) | 1);
+    }
 }
 
 /* Return one iff MSYM refers to standard ISA code.  */
@@ -398,6 +413,35 @@ msymbol_is_micromips (struct minimal_symbol *msym)
   return MSYMBOL_TARGET_FLAG_2 (msym);
 }
 
+/* Set the ISA bit in the main symbol too, complementing the corresponding
+   minimal symbol setting and reflecting the run-time value of the symbol.
+   The need for comes from the ISA bit having been cleared as code in
+   `_bfd_mips_elf_symbol_processing' separated it into the ELF symbol's
+   `st_other' STO_MIPS16 or STO_MICROMIPS annotation, making the values
+   of symbols referring to compressed code different in GDB to the values
+   used by actual code.  That in turn makes them evaluate incorrectly in
+   expressions, producing results different to what the same expressions
+   yield when compiled into the program being debugged.  */
+
+static void
+mips_make_symbol_special (struct symbol *sym, struct objfile *objfile)
+{
+  if (SYMBOL_CLASS (sym) == LOC_BLOCK)
+    {
+      /* We are in symbol reading so it is OK to cast away constness.  */
+      struct block *block = (struct block *) SYMBOL_BLOCK_VALUE (sym);
+      CORE_ADDR compact_block_start;
+      struct bound_minimal_symbol msym;
+
+      compact_block_start = BLOCK_START (block) | 1;
+      msym = lookup_minimal_symbol_by_pc (compact_block_start);
+      if (msym.minsym && !msymbol_is_mips (msym.minsym))
+	{
+	  BLOCK_START (block) = compact_block_start;
+	}
+    }
+}
+
 /* XFER a value from the big/little/left end of the register.
    Depending on the size of the value it might occupy the entire
    register or just part of it.  Make an allowance for this, aligning
@@ -1132,7 +1176,7 @@ mips_pc_is_mips (CORE_ADDR memaddr)
      stored by elfread.c in the high bit of the info field.  Use this
      to decide if the function is standard MIPS.  Otherwise if bit 0
      of the address is clear, then this is a standard MIPS function.  */
-  sym = lookup_minimal_symbol_by_pc (memaddr);
+  sym = lookup_minimal_symbol_by_pc (make_compact_addr (memaddr));
   if (sym.minsym)
     return msymbol_is_mips (sym.minsym);
   else
@@ -1150,7 +1194,7 @@ mips_pc_is_mips16 (struct gdbarch *gdbarch, CORE_ADDR memaddr)
      elfread.c in the high bit of the info field.  Use this to decide
      if the function is MIPS16.  Otherwise if bit 0 of the address is
      set, then ELF file flags will tell if this is a MIPS16 function.  */
-  sym = lookup_minimal_symbol_by_pc (memaddr);
+  sym = lookup_minimal_symbol_by_pc (make_compact_addr (memaddr));
   if (sym.minsym)
     return msymbol_is_mips16 (sym.minsym);
   else
@@ -1169,7 +1213,7 @@ mips_pc_is_micromips (struct gdbarch *gdbarch, CORE_ADDR memaddr)
      if the function is microMIPS.  Otherwise if bit 0 of the address
      is set, then ELF file flags will tell if this is a microMIPS
      function.  */
-  sym = lookup_minimal_symbol_by_pc (memaddr);
+  sym = lookup_minimal_symbol_by_pc (make_compact_addr (memaddr));
   if (sym.minsym)
     return msymbol_is_micromips (sym.minsym);
   else
@@ -1189,7 +1233,7 @@ mips_pc_isa (struct gdbarch *gdbarch, CORE_ADDR memaddr)
      this to decide if the function is MIPS16 or microMIPS or normal
      MIPS.  Otherwise if bit 0 of the address is set, then ELF file
      flags will tell if this is a MIPS16 or a microMIPS function.  */
-  sym = lookup_minimal_symbol_by_pc (memaddr);
+  sym = lookup_minimal_symbol_by_pc (make_compact_addr (memaddr));
   if (sym.minsym)
     {
       if (msymbol_is_micromips (sym.minsym))
@@ -1210,6 +1254,67 @@ mips_pc_isa (struct gdbarch *gdbarch, CORE_ADDR memaddr)
     }
 }
 
+/* Set the ISA bit correctly in the PC, used by DWARF-2 machinery.
+   The need for comes from the ISA bit having been cleared, making
+   addresses in FDE, range records, etc. referring to compressed code
+   different to those in line information, the symbol table and finally
+   the PC register.  That in turn confuses many operations.  */
+
+static CORE_ADDR
+mips_adjust_dwarf2_addr (CORE_ADDR pc)
+{
+  pc = unmake_compact_addr (pc);
+  return mips_pc_is_mips (pc) ? pc : make_compact_addr (pc);
+}
+
+/* Recalculate the line record requested so that the resulting PC has
+   the ISA bit set correctly, used by DWARF-2 machinery.  The need for
+   this adjustment comes from some records associated with compressed
+   code having the ISA bit cleared, most notably at function prologue
+   ends.  The ISA bit is in this context retrieved from the minimal
+   symbol covering the address requested, which in turn has been
+   constructed from the binary's symbol table rather than DWARF-2
+   information.  The correct setting of the ISA bit is required for
+   breakpoint addresses to correctly match against the stop PC.
+
+   As line entries can specify relative address adjustments we need to
+   keep track of the absolute value of the last line address recorded
+   in line information, so that we can calculate the actual address to
+   apply the ISA bit adjustment to.  We use PC for this tracking and
+   keep the original address there.
+
+   As such relative address adjustments can be odd within compressed
+   code we need to keep track of the last line address with the ISA
+   bit adjustment applied too, as the original address may or may not
+   have had the ISA bit set.  We use ADJ_PC for this tracking and keep
+   the adjusted address there.
+
+   For relative address adjustments we then use these variables to
+   calculate the address intended by line information, which will be
+   PC-relative, and return an updated adjustment carrying ISA bit
+   information, which will be ADJ_PC-relative.  For absolute address
+   adjustments we just return the same address that we store in ADJ_PC
+   too.
+
+   As the first line entry can be relative to an implied address value
+   of 0 we need to have the initial address set up that we store in PC
+   and ADJ_PC.  This is arranged with a call from `dwarf_decode_lines_1'
+   that sets PC to 0 and ADJ_PC accordingly, usually 0 as well.  */
+
+static CORE_ADDR
+mips_adjust_dwarf2_line (CORE_ADDR addr, int rel)
+{
+  static CORE_ADDR adj_pc;
+  static CORE_ADDR pc;
+  CORE_ADDR isa_pc;
+
+  pc = rel ? pc + addr : addr;
+  isa_pc = mips_adjust_dwarf2_addr (pc);
+  addr = rel ? isa_pc - adj_pc : isa_pc;
+  adj_pc = isa_pc;
+  return addr;
+}
+
 /* Various MIPS16 thunk (aka stub or trampoline) names.  */
 
 static const char mips_str_mips16_call_stub[] = "__mips16_call_stub_";
@@ -1259,8 +1364,6 @@ mips_read_pc (struct regcache *regcache)
   LONGEST pc;
 
   regcache_cooked_read_signed (regcache, regnum, &pc);
-  if (is_compact_addr (pc))
-    pc = unmake_compact_addr (pc);
   return pc;
 }
 
@@ -1270,8 +1373,6 @@ mips_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
   CORE_ADDR pc;
 
   pc = frame_unwind_register_signed (next_frame, gdbarch_pc_regnum (gdbarch));
-  if (is_compact_addr (pc))
-    pc = unmake_compact_addr (pc);
   /* macro/2012-04-20: This hack skips over MIPS16 call thunks as
      intermediate frames.  In this case we can get the caller's address
      from $ra, or if $ra contains an address within a thunk as well, then
@@ -1281,15 +1382,9 @@ mips_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
     {
       pc = frame_unwind_register_signed
 	     (next_frame, gdbarch_num_regs (gdbarch) + MIPS_RA_REGNUM);
-      if (is_compact_addr (pc))
-	pc = unmake_compact_addr (pc);
       if (mips_in_frame_stub (pc))
-	{
-	  pc = frame_unwind_register_signed
-		 (next_frame, gdbarch_num_regs (gdbarch) + MIPS_S2_REGNUM);
-	  if (is_compact_addr (pc))
-	    pc = unmake_compact_addr (pc);
-	}
+	pc = frame_unwind_register_signed
+	       (next_frame, gdbarch_num_regs (gdbarch) + MIPS_S2_REGNUM);
     }
   return pc;
 }
@@ -1323,10 +1418,7 @@ mips_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
   int regnum = gdbarch_pc_regnum (get_regcache_arch (regcache));
 
-  if (mips_pc_is_mips (pc))
-    regcache_cooked_write_unsigned (regcache, regnum, pc);
-  else
-    regcache_cooked_write_unsigned (regcache, regnum, make_compact_addr (pc));
+  regcache_cooked_write_unsigned (regcache, regnum, pc);
 }
 
 /* Fetch and return instruction from the specified location.  Handle
@@ -3765,9 +3857,6 @@ mips_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR addr)
 {
   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 
-  if (is_compact_addr (addr))
-    addr = unmake_compact_addr (addr);
-
   if (mips_mask_address_p (tdep) && (((ULONGEST) addr) >> 32 == 0xffffffffUL))
     /* This hack is a work-around for existing boards using PMON, the
        simulator, and any other 64-bit targets that doesn't have true
@@ -4466,25 +4555,9 @@ mips_eabi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 			    "mips_eabi_push_dummy_call: %d len=%d type=%d",
 			    argnum + 1, len, (int) typecode);
 
-      /* Function pointer arguments to mips16 code need to be made into
-         mips16 pointers.  */
-      if (typecode == TYPE_CODE_PTR
-          && TYPE_CODE (TYPE_TARGET_TYPE (arg_type)) == TYPE_CODE_FUNC)
-	{
-	  CORE_ADDR addr = extract_signed_integer (value_contents (arg),
-						   len, byte_order);
-	  if (mips_pc_is_mips (addr))
-	    val = value_contents (arg);
-	  else
-	    {
-	      store_signed_integer (valbuf, len, byte_order, 
-				    make_compact_addr (addr));
-	      val = valbuf;
-	    }
-	}
       /* The EABI passes structures that do not fit in a register by
          reference.  */
-      else if (len > regsize
+      if (len > regsize
 	  && (typecode == TYPE_CODE_STRUCT || typecode == TYPE_CODE_UNION))
 	{
 	  store_unsigned_integer (valbuf, regsize, byte_order,
@@ -5849,7 +5922,6 @@ mips_o64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   for (argnum = 0; argnum < nargs; argnum++)
     {
       const gdb_byte *val;
-      gdb_byte valbuf[MAX_REGISTER_SIZE];
       struct value *arg = args[argnum];
       struct type *arg_type = check_typedef (value_type (arg));
       int len = TYPE_LENGTH (arg_type);
@@ -5862,21 +5934,6 @@ mips_o64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 
       val = value_contents (arg);
 
-      /* Function pointer arguments to mips16 code need to be made into
-         mips16 pointers.  */
-      if (typecode == TYPE_CODE_PTR
-          && TYPE_CODE (TYPE_TARGET_TYPE (arg_type)) == TYPE_CODE_FUNC)
-	{
-	  CORE_ADDR addr = extract_signed_integer (value_contents (arg),
-						   len, byte_order);
-	  if (!mips_pc_is_mips (addr))
-	    {
-	      store_signed_integer (valbuf, len, byte_order, 
-				    make_compact_addr (addr));
-	      val = valbuf;
-	    }
-	}
-
       /* Floating point arguments passed in registers have to be
          treated specially.  On 32-bit architectures, doubles are
          passed in register pairs; the even FP register gets the
@@ -7833,27 +7890,15 @@ mips_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 
       new_pc = mips_skip_mips16_trampoline_code (frame, pc);
       if (new_pc)
-	{
-	  pc = new_pc;
-	  if (is_compact_addr (pc))
-	    pc = unmake_compact_addr (pc);
-	}
+	pc = new_pc;
 
       new_pc = find_solib_trampoline_target (frame, pc);
       if (new_pc)
-	{
-	  pc = new_pc;
-	  if (is_compact_addr (pc))
-	    pc = unmake_compact_addr (pc);
-	}
+	pc = new_pc;
 
       new_pc = mips_skip_pic_trampoline_code (frame, pc);
       if (new_pc)
-	{
-	  pc = new_pc;
-	  if (is_compact_addr (pc))
-	    pc = unmake_compact_addr (pc);
-	}
+	pc = new_pc;
     }
   while (pc != target_pc);
 
@@ -8509,6 +8554,9 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   set_gdbarch_elf_make_msymbol_special (gdbarch,
 					mips_elf_make_msymbol_special);
+  set_gdbarch_make_symbol_special (gdbarch, mips_make_symbol_special);
+  set_gdbarch_adjust_dwarf2_addr (gdbarch, mips_adjust_dwarf2_addr);
+  set_gdbarch_adjust_dwarf2_line (gdbarch, mips_adjust_dwarf2_line);
 
   regnum = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct mips_regnum);
   *regnum = mips_regnum;
diff --git a/gdb/mips-tdep.h b/gdb/mips-tdep.h
index ba29952..b42f2d6 100644
--- a/gdb/mips-tdep.h
+++ b/gdb/mips-tdep.h
@@ -155,6 +155,9 @@ enum
 /* Single step based on where the current instruction will take us.  */
 extern int mips_software_single_step (struct frame_info *frame);
 
+/* Strip the ISA (compression) bit off from ADDR.  */
+extern CORE_ADDR mips_unmake_compact_addr (CORE_ADDR addr);
+
 /* Tell if the program counter value in MEMADDR is in a standard
    MIPS function.  */
 extern int mips_pc_is_mips (bfd_vma memaddr);
diff --git a/gdb/solib.c b/gdb/solib.c
index ce9dc05..4b4386c 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -1443,8 +1443,28 @@ gdb_bfd_lookup_symbol_from_symtab (bfd *abfd,
 
 	  if (match_sym (sym, data))
 	    {
+	      struct gdbarch *gdbarch = target_gdbarch ();
+	      symaddr = sym->value;
+
+	      /* Some ELF targets fiddle with addresses of symbols they
+	         consider special.  They use minimal symbols to do that
+	         and this is needed for correct breakpoint placement,
+	         but we do not have full data here to build a complete
+	         minimal symbol, so just set the address and let the
+	         targets cope with that.  */
+	      if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
+		  && gdbarch_elf_make_msymbol_special_p (gdbarch))
+		{
+		  struct minimal_symbol msym;
+
+		  memset (&msym, 0, sizeof (msym));
+		  SET_MSYMBOL_VALUE_ADDRESS (&msym, symaddr);
+		  gdbarch_elf_make_msymbol_special (gdbarch, sym, &msym);
+		  symaddr = MSYMBOL_VALUE_RAW_ADDRESS (&msym);
+		}
+
 	      /* BFD symbols are section relative.  */
-	      symaddr = sym->value + sym->section->vma;
+	      symaddr += sym->section->vma;
 	      break;
 	    }
 	}
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 5ce3029..6e17360 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-12-12  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	* gdb.base/func-ptrs.c: New file.
+	* gdb.base/func-ptrs.exp: New file.
+
 2014-12-10  Simon Marchi  <simon.marchi@ericsson.com>
 
 	PR breakpoints/17012
diff --git a/gdb/testsuite/gdb.base/func-ptrs.c b/gdb/testsuite/gdb.base/func-ptrs.c
new file mode 100644
index 0000000..ce36074
--- /dev/null
+++ b/gdb/testsuite/gdb.base/func-ptrs.c
@@ -0,0 +1,50 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+void
+sentinel (void)
+{
+  return;
+}
+
+int
+incr (int i)
+{
+  sentinel ();
+  return i + 1;
+}
+
+int
+decr (int i)
+{
+  sentinel ();
+  return i - 1;
+}
+
+int (*calc) (int) = incr;
+
+int
+main (void)
+{
+  int i = -1;
+
+  i = calc (i);
+  i = calc (i);
+  i = calc (i);
+
+  return i;
+}
diff --git a/gdb/testsuite/gdb.base/func-ptrs.exp b/gdb/testsuite/gdb.base/func-ptrs.exp
new file mode 100644
index 0000000..c26eb9d
--- /dev/null
+++ b/gdb/testsuite/gdb.base/func-ptrs.exp
@@ -0,0 +1,95 @@
+# Copyright 2014 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set testname func-ptrs
+set srcfile ${testname}.c
+if { [prepare_for_testing ${testname}.exp ${testname} ${srcfile}] } {
+    return -1
+}
+
+if { ![runto_main] } {
+    untested ${testname}.exp
+    return -1
+}
+
+
+# First set our breakpoints.
+
+set fp_breakpoint_re \
+    "Breakpoint $decimal at $hex: file .*${srcfile}, line $decimal\\."
+gdb_test "break sentinel if calc == decr" \
+    "${fp_breakpoint_re}" \
+    "breakpoint at sentinel"
+gdb_test "break incr" \
+    "${fp_breakpoint_re}" \
+    "breakpoint at incr"
+gdb_test "break decr" \
+    "${fp_breakpoint_re}" \
+    "breakpoint at decr"
+
+
+# Check if we run through to the breakpoint in incr.
+
+gdb_test "continue" \
+    "Breakpoint $decimal, incr \\(i=-1\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+.*" \
+    "continue to incr, first time"
+
+
+# Go back up, make sure the return value is 0.
+
+gdb_test "finish" \
+    "Run till exit from #0 +incr \\(i=-1\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+($hex in )?main \\(\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+.*Value returned is \\$$decimal = 0" \
+    "go back to main from incr, first time"
+
+
+# Redirect calc and see if we run to the breakpoint in decr instead.
+
+gdb_test_no_output "set calc = decr" "set calc to decr"
+gdb_test "continue" \
+    "Breakpoint $decimal, decr \\(i=0\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+.*" \
+    "continue to decr"
+
+
+# Go back up, check if we stop in sentinel instead.
+
+gdb_test "finish" \
+    "Run till exit from #0 +decr \\(i=0\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+Breakpoint $decimal, sentinel \\(\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+.*" \
+    "stop in sentinel"
+
+
+# Go back all the way up to main, make sure the return value is -1.
+
+gdb_test_no_output "up-silently" "move up to decr"
+gdb_test "finish" \
+    "Run till exit from #1 +($hex in )?decr \\(i=0\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+($hex in )?main \\(\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+.*Value returned is \\$$decimal = -1" \
+    "go back to main from decr"
+
+
+# Reset calc and see if we run to the breakpoint in incr again.
+
+gdb_test_no_output "set calc = incr" "set calc to incr"
+gdb_test "continue" \
+    "Breakpoint $decimal, incr \\(i=-1\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+.*" \
+    "continue to incr, second time"
+
+
+# Go back up again, make sure the return value is 0.
+
+gdb_test "finish" \
+    "Run till exit from #0 +incr \\(i=-1\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+($hex in )?main \\(\\)\[ \r\n\]+at .*${srcfile}:$decimal\[\r\n\]+.*Value returned is \\$$decimal = 0" \
+    "go back to main from incr, second time"
+
+
+# All done!