>Number:         5496
>Category:       port-mac68k
>Synopsis:       Non-optimized compile dies on inline assembly.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    gnats-admin (GNATS administrator)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 25 12:35:01 1998
>Last-Modified:
>Originator:     hauke@Espresso.Rhein-Neckar.DE
>Organization:
Einzeln auftretender Radfahrer
>Release:        NetBSD 1.3E sources of 980520
>Environment:
	
System: NetBSD q700.hf.org 1.3B NetBSD 1.3B (FG54) #4: Sun Jan 25 22:02:13 CET 1998 hauke@q700:/usr/src/sys/arch/mac68k/compile/FG54 mac68k


>Description:

A kernel compile without optimization chokes on "mac68k/mac68k/macrom.c" with

cc  -pipe -m68020-40 -ffreestanding -Wall -Wstrict-prototypes -Wmissing-prototypes -Wno-main -msoft-float -I. -I../../../../arch -I../../../.. -nostdinc -DHZ="0x3c" -DM68040 -DFPSP -DFPU_EMULATE -DSYSVMSG -DSYSVSEM -DSYSVSHM -DSHMMAXPGS="0x400" -DLKM -DBUFPAGES="0x3e8" -DKTRACE -DDDB -DDDB_HISTORY_SIZE="0x32" -DDIAGNOSTIC -DDEBUG -DCOMPAT_43 -DCOMPAT_10 -DCOMPAT_11 -DCOMPAT_12 -DCOMPAT_13 -DNFSSERVER -DFIFO -DINET -DNETATALK -DMAXUSERS=16 -D_KERNEL  -Dmc68020 -Dmac68k  -c ../../../../arch/mac68k/mac68k/macrom.c
../../../../arch/mac68k/mac68k/macrom.c: In function `mrg_aline_super':
../../../../arch/mac68k/mac68k/macrom.c:760: fixed or forbidden register was spilled.
This may be due to a compiler bug or to impossible asm
statements or clauses.
cpp: output pipe has been closed
*** Error code 1

Stop.


This happens with 1.3.1 sources, too. Compiler is a -current egcs, the 
offending code is 


/*
 * Handle a supervisor mode A-line trap.
 */
void
mrg_aline_super(struct frame *frame)
{
	caddr_t trapaddr;
	u_short trapword;
	int isOStrap;
	int trapnum;
	int a0passback;
	u_int32_t a0bucket, d0bucket;
	int danprint=0; /* This shouldn't be necessary, but seems to be.  */

#if defined(MRG_DEBUG)
	printf("mrg: a super");
#endif

	trapword = *(u_short *)frame->f_pc;

	if (trapword == 0xa71e)
		danprint = 1;

#if defined(MRG_DEBUG)
	printf(" wd 0x%lx", (long)trapword);
#endif
	isOStrap = ! TRAP_TOOLBOX(trapword);
	trapnum = TRAP_NUM(trapword);

	if (danprint) {
		/*
		 * Without these print statements, ADBReInit fails on IIsi
		 * It is unclear why--perhaps a compiler bug?  delay()s do not
		 * work, nor does some assembly similar to the  printf calls.
		 * A printf(""); is sufficient, but gcc -Wall is noisy about
		 * it, so I figured backspace is harmless enough...
		 */
		printf("\010"); printf("\010");
	}

#if defined(MRG_DEBUG)
	printf(" %s # 0x%x", isOStrap? "OS" :
		"ToolBox", trapnum);
#endif

	/* Only OS Traps come to us; _alinetrap takes care of ToolBox
	  traps, which are a horrible Frankenstein-esque abomination. */

	trapaddr = mrg_OStraps[trapnum];
#if defined(MRG_DEBUG)
	printf(" addr 0x%lx\n", (long)trapaddr);
 	printf("    got:    d0 = 0x%8x,  a0 = 0x%8x, called from: 0x%8x\n",
		frame->f_regs[0], frame->f_regs[8], frame->f_pc	);
#endif
	if (trapaddr == NULL) {
		printf("unknown %s trap 0x%x, no trap address available\n",
			isOStrap ? "OS" : "ToolBox", trapword);
		panic("mrg_aline_super()");
	}
	a0passback = TRAP_PASSA0(trapword);

#if defined(MRG_TRACE)
	tron();
#endif

/* 	put a0 in a0 */
/* 	put a1 in a1 */
/* 	put d0 in d0 */
/* 	put d1 in d1 */
/*	put trapaddr in a2 */
/* save a6 */
/* 	call the damn routine */
/* restore a6 */
/* 	store d0 in d0bucket */
/* 	store a0 in d0bucket */
/* This will change a2,a1,d1,d0,a0 and possibly a6 */

	asm("
		movl	%2, d0
		movl	%3, d1
		movl	%4, a0
		movl	%5, a1
		movl	%6, a2
		jbsr	a2@
		movl	a0, %0
		movl	d0, %1"

		: "=g" (a0bucket), "=g" (d0bucket)

		: "m" (frame->f_regs[0]), "m" (frame->f_regs[1]),
		  "m" (frame->f_regs[8]), "m" (frame->f_regs[9]),
		  "g" (trapaddr)

		: "d0", "d1", "a0", "a1", "a2", "a6"

	);

#if defined(MRG_TRACE)
	troff();
#endif
#if defined(MRG_DEBUG)
	printf("    result: d0 = 0x%8x,  a0 = 0x%8x\n",
		d0bucket, a0bucket );
 	printf(" bk");
#endif

	frame->f_regs[0] = d0bucket;
	if (a0passback)
		frame->f_regs[8] = a0bucket;

	frame->f_pc += 2;	/* skip offending instruction */

#if defined(MRG_DEBUG)
	printf(" exit\n");
#endif
}


>How-To-Repeat:
Build a kernel with 

makeoptions     COPTS="-m68020-40 -pipe -ffreestanding"	

or similar, i.e. without optimization options.

>Fix:
None.
>Audit-Trail:
>Unformatted: