Path: utzoo!telly!ddsw1!lll-winken!xanth!nic.MR.NET!csd4.milw.wisc.edu!bbn!mailrus!tut.cis.ohio-state.edu!MOOSE.CITA.UTORONTO.CA!trq
From: trq@MOOSE.CITA.UTORONTO.CA (Tom Quinn)
Newsgroups: gnu.gcc.bug
Subject: bug in sparc gcc 1.32
Message-ID: <8902021530.AA02268@moose.cita.utoronto.ca>
Date: 2 Feb 89 15:30:30 GMT
Sender: daemon@tut.cis.ohio-state.edu
Distribution: gnu
Organization: GNUs Not Usenet
Lines: 114

The following code is compiled incorrectly by gcc with the "-g -O"
options.  This is gcc version 1.32 on a Sun 4/110 running SunOs 4.0.
The problem is that at line 62 it uses a global symbol (_shrinkFactor)
as the destination of a "st" instruction.  However, st can only take
an immediate of 13 bits.  The global symbol is generally greater than
13 bits, gets truncated, and running the code causes a segmentation
fault.

Tom Quinn                 Canadian Institute for Theoretical Astrophysics
trq@moose.cita.utoronto.ca
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The compile:
gcc -g -v -S -O  -sun4 -c  texx.c
gcc version 1.32
 /usr/local/lib/gcc-cpp -v -undef -D__GNUC__ -Dsparc -Dsun -Dunix -D__sparc__ -D__sun__ -D__unix__ -D__OPTIMIZE__ texx.c /tmp/cca27101.cpp
GNU CPP version 1.32
 /usr/local/lib/gcc-cc1 /tmp/cca27101.cpp -quiet -dumpbase texx.c -g -O -version -o texx.s
GNU C version 1.32 (sparc) compiled by GNU C version 1.32.

The offending assembly:
.stabn 68,0,62,LM21
LM21:
	tst %o0
	bne L5
	nop
	b L6
	mov 0,%o0
L5:
	call _atoi,0
	nop
L6:
	st %o0,[_shrinkFactor]  ! Segmentation fault here

The code:
------------------------------------------------------------------------
typedef struct _XDisplay {
	int fd;			 
} Display;
Display *XOpenDisplay();
char *XGetDefault();
char *XDisplayName();
unsigned long XBlackPixel();
extern	struct	_iobuf {
	int	_cnt;
	unsigned char *_ptr;
	unsigned char *_base;
	int	_bufsiz;
	short	_flag;
	char	_file;		 
} _iob[];
extern int	dviHHMargin;
extern int	dviVVMargin;
extern int	dviDPI;
extern int      dviBlackness;
extern char	*ProgName;
extern int dviInit();
Display *DISP;
static int Leaves;
int shrinkFactor[2 ];
static int reverse = 0;
char *malloc(), *calloc(), *index();
int Black_Pixel = 0;
main(argc, argv)
    int argc;
    char **argv;
{
    char *display = 0 ;
    char *option;
    int bwidth = 2;
    char *fore_color;
    char *back_color;
    char *high_color;
    char *brdr_color;
    char *mous_color;
    double atof();
    char *getenv();
    ProgName = *argv;
    argv++;
    argc--;
    if ((DISP = XOpenDisplay(display)) == 0 ) {
	fprintf((&_iob[2]) , "[%s] Can't open display '%s'\n",
		ProgName, XDisplayName(display));
	exit(1);
    }
    Black_Pixel = XBlackPixel(DISP, 0);
    if ((option = XGetDefault(DISP, ProgName, "ReverseVideo")) &&
	strcmp(option, "on") == 0)
	reverse = 1;
    if (option = XGetDefault(DISP, ProgName, "BorderWidth"))
	bwidth = atoi(option);
    fore_color = XGetDefault(DISP, ProgName, "ForeGround");
    back_color = XGetDefault(DISP, ProgName, "BackGround");
    high_color = XGetDefault(DISP, ProgName, "Highlight");
    brdr_color = XGetDefault(DISP, ProgName, "Border");
    mous_color = XGetDefault(DISP, ProgName, "Mouse");
    option = XGetDefault(DISP, ProgName, "NormalShrink");
    shrinkFactor[0 ] = (option == 0) ? 0 : atoi(option);
    option = XGetDefault(DISP, ProgName, "LargeShrink");
    shrinkFactor[1 ]  = (option == 0) ? 0 : atoi(option);
    option = XGetDefault(DISP, ProgName, "Blackness");
    dviBlackness = (option == 0) ? 3  : atoi(option);
    option = XGetDefault(DISP, ProgName, "Leaves");
    Leaves = (option == 0) ? 0 : atoi(option);
    option = XGetDefault(DISP, ProgName, "Dpi");
    dviDPI = (option == 0) ? 300  : atoi(option);
    option = XGetDefault(DISP, ProgName, "TopMargin");
    dviVVMargin = (option == 0) ? 300   : atof(option) * dviDPI;
    option = XGetDefault(DISP, ProgName, "SideMargin");
    dviHHMargin = (option == 0) ? 300   : atof(option) * dviDPI;
    dviInit();
}