Re: assertion failure with gas and broken syntax

[Nick Clifton]

Hi Per, Hi H.J.,

H.J. - this email is in response to a x86 assembler bug report from Per 
that was posted here:

  http://lists.gnu.org/archive/html/bug-binutils/2008-09/msg00006.html

I have a patch to fix the problem (attached) but I am not sure if you 
will like it.  Possibly the error should be caught earlier, before the 
attempt to apply the fixup ?

The patch includes a new test to cover the example in the original email 
and a tweak to an existing test that is altered by the patch.  If you 
are OK with it please let me know and I will apply the patch to the sources.

Cheers
  Nick

gas/ChangeLog
2008-09-18  Nick Clifton  <address@hidden>

        * config/tc-i386.c (md_apply_fix): Refuse fixups against register
        symbols.

gas/testsuite/ChangeLog
2008-09-18  Nick Clifton  <address@hidden>

        * gas/i386/inval-symbol.s: New test.
        * gas/i386/inval-symbol.l: Expected listing.
        * gas/i386/i386.exp: Run new test.
        * gas/i386/inval-equ-2.l: Update expecting listing output.

Index: gas/config/tc-i386.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-i386.c,v
retrieving revision 1.352
diff -c -3 -p -r1.352 tc-i386.c
*** gas/config/tc-i386.c        3 Sep 2008 15:44:33 -0000       1.352
--- gas/config/tc-i386.c        18 Sep 2008 11:35:53 -0000
*************** md_apply_fix (fixP, valP, seg)
*** 7644,7649 ****
--- 7644,7658 ----
    char *p = fixP->fx_where + fixP->fx_frag->fr_literal;
    valueT value = *valP;
  
+   if (fixP->fx_addsy != NULL
+       && S_GET_SEGMENT (fixP->fx_addsy) == reg_section)
+     {
+       as_bad_where (fixP->fx_file, fixP->fx_line,
+                   _("cannot use a register name as symbolic value"));
+       fixP->fx_done = 1;
+       return;
+     }
+   
  #if !defined (TE_Mach)
    if (fixP->fx_pcrel)
      {
Index: gas/testsuite/gas/i386/i386.exp
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/i386/i386.exp,v
retrieving revision 1.105
diff -c -3 -p -r1.105 i386.exp
*** gas/testsuite/gas/i386/i386.exp     28 Aug 2008 09:42:11 -0000      1.105
--- gas/testsuite/gas/i386/i386.exp     18 Sep 2008 11:35:53 -0000
*************** if [expr ([istarget "i*86-*-*"] ||  [ist
*** 28,33 ****
--- 28,34 ----
      run_list_test "inval" "-al"
      run_list_test "segment" "-al"
      run_list_test "inval-seg" "-al"
+     run_list_test "inval-symbol" "-al"
      run_list_test "modrm" "-al --listing-lhs-width=2"
      run_dump_test "naked"
      run_dump_test "opcode"
Index: gas/testsuite/gas/i386/inval-equ-2.l
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/i386/inval-equ-2.l,v
retrieving revision 1.1
diff -c -3 -p -r1.1 inval-equ-2.l
*** gas/testsuite/gas/i386/inval-equ-2.l        3 Mar 2008 15:28:58 -0000       
1.1
--- gas/testsuite/gas/i386/inval-equ-2.l        18 Sep 2008 11:35:53 -0000
***************
*** 1,4 ****
--- 1,7 ----
  .*: Assembler messages:
+ .*:3: Error: .*
+ .*:5: Error: .*
+ .*:8: Error: .*
  .*:8: Error: .*
  .*:8: Error: .*
  .*:8: Error: .*
*************** GAS LISTING .*
*** 7,19 ****
  
  [     ]*1[    ]+\.globl  bar1
  [     ]*2[    ]+\.set    bar1,\(%eax\+1\)
! [     ]*3[    ]+\?\?\?\? A12A0000             mov bar1,%eax
  [     ]*3[    ]+00
  [     ]*4[    ]+\.set    bar2,\(%eax\+1\)
! [     ]*5[    ]+\?\?\?\? A12A0000             mov bar2,%eax
  [     ]*5[    ]+00
  [     ]*6[    ]+\.globl  bar2
  [     ]*7[    ]+\.set    bar3,\(%eax\+1\)
! [     ]*8[    ]+\?\?\?\? A12A0000             mov bar3,%eax
  \*\*\*\*  Error:can't make global register symbol `bar3'
  [     ]*8[    ]+00
--- 10,22 ----
  
  [     ]*1[    ]+\.globl  bar1
  [     ]*2[    ]+\.set    bar1,\(%eax\+1\)
! [     ]*3[    ]+\?\?\?\? A1..0000             mov bar1,%eax
  [     ]*3[    ]+00
  [     ]*4[    ]+\.set    bar2,\(%eax\+1\)
! [     ]*5[    ]+\?\?\?\? A1..0000             mov bar2,%eax
  [     ]*5[    ]+00
  [     ]*6[    ]+\.globl  bar2
  [     ]*7[    ]+\.set    bar3,\(%eax\+1\)
! [     ]*8[    ]+\?\?\?\? A1..0000             mov bar3,%eax
  \*\*\*\*  Error:can't make global register symbol `bar3'
  [     ]*8[    ]+00
*** /dev/null   2008-09-18 08:05:37.567254421 +0100
--- gas/testsuite/gas/i386/inval-symbol.s       2008-09-18 11:33:38.000000000 
+0100
***************
*** 0 ****
--- 1,2 ----
+       .text
+       cmp     (%ax)-1, %ax
*** /dev/null   2008-09-18 08:05:37.567254421 +0100
--- gas/testsuite/gas/i386/inval-symbol.l       2008-09-18 11:39:06.000000000 
+0100
***************
*** 0 ****
--- 1,9 ----
+ .*: Assembler messages:
+ .*:2: Error: .*
+ GAS LISTING .*
+ 
+ 
+    1 [        ]*      .text
+    2 .*       cmp     \(%ax\)-1, %ax
+ .*Error:cannot use a register name as symbolic value
+    2 .*0+0