Binutils with MCST patches
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Yao Qi 6d5f0679fe Handle the effect of skipping prologue
break-asm-file.exp has some manually written dwarf to create some line
number entries like this,

  [0x0000013d]  Extended opcode 2: set Address to 0x40053f
  [0x00000144]  Advance Line by 4 to 7
  [0x00000146]  Copy
  [0x00000147]  Extended opcode 2: set Address to 0x400541
  [0x0000014e]  Advance Line by 1 to 8
  [0x00000150]  Copy
  [0x00000151]  Extended opcode 2: set Address to 0x400547
  [0x00000158]  Extended opcode 1: End of Sequence

0x40053f is the start address of function func, and is mapped to line
7.  0x400541 is within function func, and is mapped to line 8.

(gdb) disassemble /r 0x40053f,+8
Dump of assembler code from 0x40053f to 0x400547:
   0x000000000040053f <func+0>: 00 00   add    %al,(%rax)
   0x0000000000400541 <func+2>: 00 00   add    %al,(%rax)
   0x0000000000400543 <func+4>: 00 00   add    %al,(%rax)
   0x0000000000400545 <func+6>: 00 00   add    %al,(%rax)

in the following test,

(gdb) break a/break-asm-file0.s:func
Breakpoint 1 at 0x40053f: file a/break-asm-file0.s, line 7.

As we can see, breakpoint is set at the start address of function func
on x86, which means no prologue is skipped.  On other targets, such as
arm and aarch64, breakpoint is set at the address *after* the start
address, which is mapped to line 8.  Then test fails.

In fact, it is lucky this test doesn't fail on x86 and x86_64, whose
gdbarch method skip_prologue doesn't reply on skip_prologue_using_sal
if producer isn't clang.

  if (find_pc_partial_function (start_pc, NULL, &func_addr, NULL))
    {
      CORE_ADDR post_prologue_pc
	= skip_prologue_using_sal (gdbarch, func_addr);
      struct compunit_symtab *cust = find_pc_compunit_symtab (func_addr);

      /* Clang always emits a line note before the prologue and another
	 one after.  We trust clang to emit usable line notes.  */
      if (post_prologue_pc
	  && (cust != NULL
	      && COMPUNIT_PRODUCER (cust) != NULL
	      && startswith (COMPUNIT_PRODUCER (cust), "clang ")))
        return max (start_pc, post_prologue_pc);
    }

so it doesn't return and go further to prologue analyser.  Since ".int 0"
isn't an instruction of prologue, nothing is skipped, starting address
is used, and test passes.

however, on targets which don't have such producer checking, the first
line number entry is skipped, and skip_prologue_using_sal returns sal
represents the second line number entry.

The idea of this patch is to force GDB stop at somewhere which is stilled
mapped to line 7 after skipping prologue.  I choose to add a new line
number entry for the following instruction but mapped to the same line (7),
because I see the comments in dwarf2read.c,

   ... fact that two consecutive
   line number entries for the same line is a heuristic used by gcc
   to denote the end of the prologue.

then the line table becomes:

  [0x000000d4]  Extended opcode 2: set Address to 0x400529
  [0x000000db]  Advance Line by 4 to 7
  [0x000000dd]  Copy
  [0x000000de]  Extended opcode 2: set Address to 0x40052a
  [0x000000e5]  Advance Line by 0 to 7
  [0x000000e7]  Copy
  [0x000000e8]  Extended opcode 2: set Address to 0x40052b
  [0x000000ef]  Advance Line by 1 to 8
  [0x000000f1]  Copy
  [0x000000f2]  Extended opcode 2: set Address to 0x40052c
  [0x000000f9]  Extended opcode 1: End of Sequence

gdb/testsuite:

2015-03-26  Yao Qi  <yao.qi@linaro.org>

	PR testsuite/18139
	* gdb.linespec/break-asm-file0.s (func): New label .Lfunc_2.
	Add a line number entry for the same line.
	* gdb.linespec/break-asm-file1.s (func): New label .Lfunc_2.
	Add a line number entry for the same line.
2015-03-26 08:29:48 +00:00
bfd Automatic date update in version.in 2015-03-26 00:00:08 +00:00
binutils Add support for G13 and G14 flag bits in RL78 ELF binaries. 2015-03-19 15:37:43 +00:00
config Sync isl.m4 with GCC tree 2015-03-16 08:51:37 -07:00
cpu
elfcpp [gold] Recognize DWARF5/GCC5 DW_LANG_Fortran03 and DW_LANG_Fortran08. 2015-02-17 08:08:24 +01:00
etc
gas [AARCH64]Fix "align directive causes MAP_DATA symbol to be lost" 2015-03-25 12:33:07 +00:00
gdb Handle the effect of skipping prologue 2015-03-26 08:29:48 +00:00
gold PR18147, relocation overflow when --unresolved-symbols=ignore-all 2015-03-24 17:06:12 +10:30
gprof Regenerate Makeile.in file for copyright update 2015-01-02 22:27:27 +10:30
include Extend arm_feature_set struct to provide more bits 2015-03-24 14:08:08 +08:00
intl
ld [AArch64] Implement branch over stub section. 2015-03-25 15:16:04 +00:00
libdecnumber Another part of fixing "make TAGS". 2015-01-22 21:07:31 +02:00
libiberty strerror.c: Do not declare sys_nerr or sys_errlist if already macros 2015-01-19 16:29:07 +01:00
opcodes powerpc: Only initialise opcode indices once 2015-03-26 09:12:50 +11:00
readline
sim sim: m68hc11/mips/mn10300/v850: add basic sim_pc_get 2015-03-24 02:43:42 -04:00
texinfo
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ChangeLog Exclude target-zlib if target-libjava isn't built 2015-03-17 17:07:22 -07:00
compile
config-ml.in Sync config-ml.in with GCC trunk 2015-03-17 05:15:34 -07:00
config.guess
config.rpath
config.sub
configure Exclude target-zlib if target-libjava isn't built 2015-03-17 17:07:22 -07:00
configure.ac Exclude target-zlib if target-libjava isn't built 2015-03-17 17:07:22 -07:00
COPYING
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depcomp
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Makefile.def Update top-level files from GCC trunk 2015-03-16 09:12:37 -07:00
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.