[parisc-linux] hppa64 gcc sizeof() bug?

[parisc-linux] hppa64 gcc sizeof() bug?

[Richard Hirst]

Hi Alan,
  The following shows the compiler getting confused over the size
of a struct.  This is with a gcc/binutils built since the last
fix you did for me.

Richard


[rhirst@rhirst play]$ cat tc.c


typedef unsigned int u32;
#define NULL ((void *)0)

struct kernel_sym32 {
        u32 value;
        char name[60];
};

extern int sys_get_kernel_syms(void *);
extern int thing(struct kernel_sym32 *table);

int sys32_get_kernel_syms(struct kernel_sym32 *table)
{
        int len, i;

        len = sizeof (struct kernel_sym32);
        for (i = 0; i < len; i++, table += sizeof (struct kernel_sym32)) {
                if (thing(table))
                        break;
        }
        return i;
}


[rhirst@rhirst play]$ hppa64-linux-gcc -S -o tc.s -O2 tc.c
[rhirst@rhirst play]$ cat tc.s


        .LEVEL 2.0w
gcc2_compiled.:
        .text
        .align 8
.globl sys32_get_kernel_syms
                .type            sys32_get_kernel_syms,@function
sys32_get_kernel_syms:
        .PROC
        .CALLINFO FRAME=128,CALLS,SAVE_RP,ENTRY_GR=6
        .ENTRY
        std %r2,-16(%r30)
        ldo 128(%r30),%r30
        std %r6,-128(%r30)
        ldi 64,%r6		<<< Good, struct is 64 bytes
        std %r5,-120(%r30)
        ldi 0,%r5
        std %r4,-112(%r30)
        copy %r27,%r4
        std %r3,-104(%r30)
        copy %r26,%r3
.L3:
        copy %r3,%r26
        ldo 4096(%r3),%r3	<<< BAD struct is not 4096 bytes!
        cmpb,<= %r6,%r5,.L4
        ldo -16(%r30),%r29
        b,l thing,%r2
        nop
        copy %r4,%r27
        cmpib,= 0,%r28,.L5
        ldo 1(%r5),%r19
.L4:
        copy %r5,%r28
        ldd -144(%r30),%r2
        ldd -120(%r30),%r5
        ldd -112(%r30),%r4
        ldd -104(%r30),%r3
        bve (%r2)
        ldd,mb -128(%r30),%r6
.L5:
        b .L3
        extrd,s %r19,63,32,%r5
        .EXIT
        .PROCEND
.Lfe1:
        .size   sys32_get_kernel_syms,.Lfe1-sys32_get_kernel_syms
        .ident  "GCC: (GNU) 2.96 20000925 (experimental)"
[rhirst@rhirst play]$ 

Re: [parisc-linux] hppa64 gcc sizeof() bug?

[Richard Hirst]

On Wed, Dec 06, 2000 at 11:52:03AM +0000, Richard Hirst wrote:
> Hi Alan,
>   The following shows the compiler getting confused over the size
> of a struct.  This is with a gcc/binutils built since the last
> fix you did for me.
> 
> Richard
> 
> 
> [rhirst@rhirst play]$ cat tc.c
> 
> 
> typedef unsigned int u32;
> #define NULL ((void *)0)
> 
> struct kernel_sym32 {
>         u32 value;
>         char name[60];
> };
> 
> extern int sys_get_kernel_syms(void *);
> extern int thing(struct kernel_sym32 *table);
> 
> int sys32_get_kernel_syms(struct kernel_sym32 *table)
> {
>         int len, i;
> 
>         len = sizeof (struct kernel_sym32);
>         for (i = 0; i < len; i++, table += sizeof (struct kernel_sym32)) {
>                 if (thing(table))
>                         break;
>         }
>         return i;
> }

Just changed it to 'table += 64' and it still generates code that
adds 4096, so sizeof is not relevant.

Richard

Re: [parisc-linux] hppa64 gcc sizeof() bug?

[Richard Hirst]

On Wed, Dec 06, 2000 at 11:52:03AM +0000, Richard Hirst wrote:
> Hi Alan,
>   The following shows the compiler getting confused over the size
> of a struct.  This is with a gcc/binutils built since the last
> fix you did for me.

As Alan has kindly pointed out to me, I goofed.  In my defence, I
did copy the garbage code from the sparc64 port ;)

Richard

Re: [parisc-linux] hppa64 gcc sizeof() bug?

[Grant Grundler]

Richard Hirst wrote:

> > int sys32_get_kernel_syms(struct kernel_sym32 *table)
...
> Just changed it to 'table += 64' and it still generates code that
> adds 4096, so sizeof is not relevant.

Right. sizeof() works fine.
table points to something that is 4096/64 (64 bytes) in size.
table+=1 results in adding 4096/64 to table.
The code should read "((char *) table) += 64" or "table++".

grant

Grant Grundler
Unix Systems Enablement Lab
+1.408.447.7253