BR 2010180: outobj: Garbage may be written in a last PUBDEF

The testcase illustrates the problem. After "nasm -f obj
alonesym.nasm"
let's look to dump:

======
PUBDEF386(91) recnum:5, offset:0000005bh, len:03f9h, chksum:bbh(bb)
Group: 0, Seg: 1
00020000h - 'sym0000' Type:0
00020004h - 'sym0001' Type:0
....
00020134h - 'sym0077' Type:0

PUBDEF(90) recnum:6, offset:00000457h, len:000ah, chksum:b6h(b6)
Group: 0, Seg: 1
00000138h - 's' Type:2
0000b600h - '' Type:0
======

The problem is while 's' offset is 20138h it is marked as type 90h not
91h.  The root cause is located in obj_x():

static ObjRecord *obj_x(ObjRecord * orp, uint32_t val)
{
    if (orp->type & 1)
    	orp->x_size = 32;
    if (val > 0xFFFF)
        orp = obj_force(orp, 32);
    if (orp->x_size == 32)
        return (obj_dword(orp, val));
    orp->x_size = 16;
    return (obj_word(orp, val));
}

It sets up x_size and than writes data. In the testcase data are the
offset and this offset overflows a record. In this case the record is
emitted and its x_size is cleared. Because this is last PUBDEF the new
record with only 's' symbol is emitted also but its x_size is not 32
(it's still zero) so obj_fwrite doesn't switch to 91h type.

The problem seems to be very generic and expected to be occurred on
many other record types as well.

        ----

And the fix is simple:

if (orp->x_size == 32)
{
  ObjRecord * nxt = obj_dword(orp, val);
  nxt->x_size = 32; /* x_size is cleared when a record overflows */
  return nxt;
}

1 files changed, 163 insertions, 0 deletions

diff --git a/test/alonesym-obj.asm b/test/alonesym-obj.asm
new file mode 100644
index 00000000..6be4d5db
--- /dev/null
+++ b/test/alonesym-obj.asm
@@ -0,0 +1,163 @@
+section         DOS32DATA align=16 public use32 FLAT class=DOS32DATA
+
+                global sym0000
+                global sym0001
+                global sym0002
+                global sym0003
+                global sym0004
+                global sym0005
+                global sym0006
+                global sym0007
+                global sym0008
+                global sym0009
+                global sym0010
+                global sym0011
+                global sym0012
+                global sym0013
+                global sym0014
+                global sym0015
+                global sym0016
+                global sym0017
+                global sym0018
+                global sym0019
+                global sym0020
+                global sym0021
+                global sym0022
+                global sym0023
+                global sym0024
+                global sym0025
+                global sym0026
+                global sym0027
+                global sym0028
+                global sym0029
+                global sym0030
+                global sym0031
+                global sym0032
+                global sym0033
+                global sym0034
+                global sym0035
+                global sym0036
+                global sym0037
+                global sym0038
+                global sym0039
+                global sym0040
+                global sym0041
+                global sym0042
+                global sym0043
+                global sym0044
+                global sym0045
+                global sym0046
+                global sym0047
+                global sym0048
+                global sym0049
+                global sym0050
+                global sym0051
+                global sym0052
+                global sym0053
+                global sym0054
+                global sym0055
+                global sym0056
+                global sym0057
+                global sym0058
+                global sym0059
+                global sym0060
+                global sym0061
+                global sym0062
+                global sym0063
+                global sym0064
+                global sym0065
+                global sym0066
+                global sym0067
+                global sym0068
+                global sym0069
+                global sym0070
+                global sym0071
+                global sym0072
+                global sym0073
+                global sym0074
+                global sym0075
+                global sym0076
+                global sym0077
+                global s
+
+
+                resb 20000h
+sym0000         resd 1
+sym0001         resd 1
+sym0002         resd 1
+sym0003         resd 1
+sym0004         resd 1
+sym0005         resd 1
+sym0006         resd 1
+sym0007         resd 1
+sym0008         resd 1
+sym0009         resd 1
+sym0010         resd 1
+sym0011         resd 1
+sym0012         resd 1
+sym0013         resd 1
+sym0014         resd 1
+sym0015         resd 1
+sym0016         resd 1
+sym0017         resd 1
+sym0018         resd 1
+sym0019         resd 1
+sym0020         resd 1
+sym0021         resd 1
+sym0022         resd 1
+sym0023         resd 1
+sym0024         resd 1
+sym0025         resd 1
+sym0026         resd 1
+sym0027         resd 1
+sym0028         resd 1
+sym0029         resd 1
+sym0030         resd 1
+sym0031         resd 1
+sym0032         resd 1
+sym0033         resd 1
+sym0034         resd 1
+sym0035         resd 1
+sym0036         resd 1
+sym0037         resd 1
+sym0038         resd 1
+sym0039         resd 1
+sym0040         resd 1
+sym0041         resd 1
+sym0042         resd 1
+sym0043         resd 1
+sym0044         resd 1
+sym0045         resd 1
+sym0046         resd 1
+sym0047         resd 1
+sym0048         resd 1
+sym0049         resd 1
+sym0050         resd 1
+sym0051         resd 1
+sym0052         resd 1
+sym0053         resd 1
+sym0054         resd 1
+sym0055         resd 1
+sym0056         resd 1
+sym0057         resd 1
+sym0058         resd 1
+sym0059         resd 1
+sym0060         resd 1
+sym0061         resd 1
+sym0062         resd 1
+sym0063         resd 1
+sym0064         resd 1
+sym0065         resd 1
+sym0066         resd 1
+sym0067         resd 1
+sym0068         resd 1
+sym0069         resd 1
+sym0070         resd 1
+sym0071         resd 1
+sym0072         resd 1
+sym0073         resd 1
+sym0074         resd 1
+sym0075         resd 1
+sym0076         resd 1
+sym0077         resd 1
+s               resd 1