[binutils-gdb] Fix "set architecture mips:10000" crash

[Pedro Alves <palves at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e6c2f47b45315ba13f25fb57e51389d0c5ed0701

commit e6c2f47b45315ba13f25fb57e51389d0c5ed0701
Author: Pedro Alves <palves@redhat.com>
Date:   Mon Mar 7 00:10:30 2016 +0000

    Fix "set architecture mips:10000" crash
    
    Fix this GDB crash:
    
      $ gdb -ex "set architecture mips:10000"
      Segmentation fault (core dumped)
    
    Backtrace:
    
      Program received signal SIGSEGV, Segmentation fault.
      0x0000000000495b1b in mips_gdbarch_init (info=..., arches=0x0) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/mips-tdep.c:8436
      8436              if (bfd_get_flavour (info.abfd) == bfd_target_elf_flavour
      (top-gdb) bt
      #0  0x0000000000495b1b in mips_gdbarch_init (info=..., arches=0x0) at .../src/gdb/mips-tdep.c:8436
      #1  0x00000000007348a6 in gdbarch_find_by_info (info=...) at .../src/gdb/gdbarch.c:5155
      #2  0x000000000073563c in gdbarch_update_p (info=...) at .../src/gdb/arch-utils.c:522
      #3  0x0000000000735585 in set_architecture (ignore_args=0x0, from_tty=1, c=0x26bc870) at .../src/gdb/arch-utils.c:496
      #4  0x00000000005f29fd in do_sfunc (c=0x26bc870, args=0x0, from_tty=1) at .../src/gdb/cli/cli-decode.c:121
      #5  0x00000000005fd3f3 in do_set_command (arg=0x7fffffffdcdd "mips:10000", from_tty=1, c=0x26bc870) at .../src/gdb/cli/cli-setshow.c:455
      #6  0x0000000000836157 in execute_command (p=0x7fffffffdcdd "mips:10000", from_tty=1) at .../src/gdb/top.c:460
      #7  0x000000000071abfb in catch_command_errors (command=0x835f6b <execute_command>, arg=0x7fffffffdccc "set architecture mips:10000", from_tty=1)
          at .../src/gdb/main.c:368
      #8  0x000000000071bf4f in captured_main (data=0x7fffffffd750) at .../src/gdb/main.c:1132
      #9  0x0000000000716737 in catch_errors (func=0x71af44 <captured_main>, func_args=0x7fffffffd750, errstring=0x106b9a1 "", mask=RETURN_MASK_ALL)
          at .../src/gdb/exceptions.c:240
      #10 0x000000000071bfe6 in gdb_main (args=0x7fffffffd750) at .../src/gdb/main.c:1164
      #11 0x000000000040a6ad in main (argc=4, argv=0x7fffffffd858) at .../src/gdb/gdb.c:32
      (top-gdb)
    
    We already check whether info.abfd is NULL before all other
    bfd_get_flavour calls in the same function.  Just this one case was
    missing.
    
    (This was exposed by a WIP test that tries all "set architecture ARCH"
    values.)
    
    gdb/ChangeLog:
    2016-03-07  Pedro Alves  <palves@redhat.com>
    
    	* mips-tdep.c (mips_gdbarch_init): Check whether info.abfd is NULL
    	before calling bfd_get_flavour.

Diff:
---
 gdb/ChangeLog   | 5 +++++
 gdb/mips-tdep.c | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b84326c..3f020ff 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2016-03-07  Pedro Alves  <palves@redhat.com>
+
+	* mips-tdep.c (mips_gdbarch_init): Check whether info.abfd is NULL
+	before calling bfd_get_flavour.
+
 2016-03-05  Pitchumani Sivanupandi  <pitchumani.s@atmel.com>
 
 	* avr-tdep.c (AVR_LAST_ARG_REGNUM): Define.
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 63c1560..178a163 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -8433,7 +8433,8 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 	  /* On Irix, ELF64 executables use the N64 ABI.  The
 	     pseudo-sections which describe the ABI aren't present
 	     on IRIX.  (Even for executables created by gcc.)  */
-	  if (bfd_get_flavour (info.abfd) == bfd_target_elf_flavour
+	  if (info.abfd != NULL
+	      && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour
 	      && elf_elfheader (info.abfd)->e_ident[EI_CLASS] == ELFCLASS64)
 	    found_abi = MIPS_ABI_N64;
 	  else