[PATCH] gcc 3.0.1 warnings about multi-line literals

[PATCH] gcc 3.0.1 warnings about multi-line literals

[John Hawkes]

This patch eliminates gcc 3.0.1 warnings, "multi-line string literals are
deprecated", in two include/asm-i386 files.  Patches cleanly for at least
2.4.10 and 2.4.12, and tested in 2.4.10.

John Hawkes
hawkes@sgi.com


diff -X /build4/hawkes/Build/ignore.dirs -Naur linux-2.4.12/include/asm-i386/checksum.h linux-2.4.12-3.0.1/include/asm-i386/checksum.h
--- linux-2.4.12/include/asm-i386/checksum.h	Thu Jul 26 13:41:22 2001
+++ linux-2.4.12-3.0.1/include/asm-i386/checksum.h	Mon Oct 22 10:40:14 2001
@@ -69,25 +69,24 @@
 					  unsigned int ihl) {
 	unsigned int sum;
 
-	__asm__ __volatile__("
-	    movl (%1), %0
-	    subl $4, %2
-	    jbe 2f
-	    addl 4(%1), %0
-	    adcl 8(%1), %0
-	    adcl 12(%1), %0
-1:	    adcl 16(%1), %0
-	    lea 4(%1), %1
-	    decl %2
-	    jne	1b
-	    adcl $0, %0
-	    movl %0, %2
-	    shrl $16, %0
-	    addw %w2, %w0
-	    adcl $0, %0
-	    notl %0
-2:
-	    "
+	__asm__ __volatile__(
+	    "movl (%1), %0 \n\t" \
+	    "subl $4, %2 \n\t" \
+	    "jbe 2f \n\t" \
+	    "addl 4(%1), %0 \n\t" \
+	    "adcl 8(%1), %0 \n\t" \
+	    "adcl 12(%1), %0 \n\t" \
+	    "1:\t adcl 16(%1), %0 \n\t" \
+	    "lea 4(%1), %1 \n\t" \
+	    "decl %2 \n\t" \
+	    "jne 1b \n\t" \
+	    "adcl $0, %0 \n\t" \
+	    "movl %0, %2 \n\t" \
+	    "shrl $16, %0 \n\t" \
+	    "addw %w2, %w0 \n\t" \
+	    "adcl $0, %0 \n\t" \
+	    "notl %0 \n\t" \
+	    "2: "
 	/* Since the input registers which are loaded with iph and ipl
 	   are modified, we must also specify them as outputs, or gcc
 	   will assume they contain their original values. */
@@ -102,10 +101,8 @@
 
 static inline unsigned int csum_fold(unsigned int sum)
 {
-	__asm__("
-		addl %1, %0
-		adcl $0xffff, %0
-		"
+	__asm__("addl %1, %0 \n\t" \
+		"adcl $0xffff, %0 \n\t"
 		: "=r" (sum)
 		: "r" (sum << 16), "0" (sum & 0xffff0000)
 	);
@@ -118,12 +115,11 @@
 						   unsigned short proto,
 						   unsigned int sum) 
 {
-    __asm__("
-	addl %1, %0
-	adcl %2, %0
-	adcl %3, %0
-	adcl $0, %0
-	"
+    __asm__(
+	"addl %1, %0 \n\t" \
+	"adcl %2, %0 \n\t" \
+	"adcl %3, %0 \n\t" \
+	"adcl $0, %0 \n\t"
 	: "=r" (sum)
 	: "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
     return sum;
@@ -158,19 +154,17 @@
 						     unsigned short proto,
 						     unsigned int sum) 
 {
-	__asm__("
-		addl 0(%1), %0
-		adcl 4(%1), %0
-		adcl 8(%1), %0
-		adcl 12(%1), %0
-		adcl 0(%2), %0
-		adcl 4(%2), %0
-		adcl 8(%2), %0
-		adcl 12(%2), %0
-		adcl %3, %0
-		adcl %4, %0
-		adcl $0, %0
-		"
+	__asm__("addl 0(%1), %0 \n\t" \
+		"adcl 4(%1), %0 \n\t" \
+		"adcl 8(%1), %0 \n\t" \
+		"adcl 12(%1), %0 \n\t" \
+		"adcl 0(%2), %0 \n\t" \
+		"adcl 4(%2), %0 \n\t" \
+		"adcl 8(%2), %0 \n\t" \
+		"adcl 12(%2), %0 \n\t" \
+		"adcl %3, %0 \n\t" \
+		"adcl %4, %0 \n\t" \
+		"adcl $0, %0 \n\t"
 		: "=&r" (sum)
 		: "r" (saddr), "r" (daddr), 
 		  "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
diff -X /build4/hawkes/Build/ignore.dirs -Naur linux-2.4.12/include/asm-i386/floppy.h linux-2.4.12-3.0.1/include/asm-i386/floppy.h
--- linux-2.4.12/include/asm-i386/floppy.h	Wed Oct 10 23:44:34 2001
+++ linux-2.4.12-3.0.1/include/asm-i386/floppy.h	Mon Oct 22 10:44:36 2001
@@ -75,28 +75,28 @@
 
 #ifndef NO_FLOPPY_ASSEMBLER
 	__asm__ (
-       "testl %1,%1
-	je 3f
-1:	inb %w4,%b0
-	andb $160,%b0
-	cmpb $160,%b0
-	jne 2f
-	incw %w4
-	testl %3,%3
-	jne 4f
-	inb %w4,%b0
-	movb %0,(%2)
-	jmp 5f
-4:     	movb (%2),%0
-	outb %b0,%w4
-5:	decw %w4
-	outb %0,$0x80
-	decl %1
-	incl %2
-	testl %1,%1
-	jne 1b
-3:	inb %w4,%b0
-2:	"
+	"testl %1,%1 \n\t" \
+	"je 3f \n\t" \
+	"1:\t inb %w4,%b0 \n\t" \
+	"andb $160,%b0 \n\t" \
+	"cmpb $160,%b0 \n\t" \
+	"jne 2f \n\t" \
+	"incw %w4 \n\t" \
+	"testl %3,%3 \n\t" \
+	"jne 4f \n\t" \
+	"inb %w4,%b0 \n\t" \
+	"movb %0,(%2) \n\t" \
+	"jmp 5f \n\t" \
+	"4:\t movb (%2),%0 \n\t" \
+	"outb %b0,%w4 \n\t" \
+	"5:\t decw %w4 \n\t" \
+	"outb %0,$0x80 \n\t" \
+	"decl %1 \n\t" \
+	"incl %2 \n\t" \
+	"testl %1,%1 \n\t" \
+	"jne 1b \n\t" \
+	"3:\t inb %w4,%b0 \n\t" \
+	"2:\n\t"
        : "=a" ((char) st), 
        "=c" ((long) virtual_dma_count), 
        "=S" ((long) virtual_dma_addr)

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[Benjamin LaHaise]

On Mon, Oct 22, 2001 at 01:05:10PM -0700, John Hawkes wrote:
> This patch eliminates gcc 3.0.1 warnings, "multi-line string literals are
> deprecated", in two include/asm-i386 files.  Patches cleanly for at least
> 2.4.10 and 2.4.12, and tested in 2.4.10.

Please reject this patch.  The gcc folks are wrong in this case.

		-ben

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[Alan Cox]

> On Mon, Oct 22, 2001 at 01:05:10PM -0700, John Hawkes wrote:
> > This patch eliminates gcc 3.0.1 warnings, "multi-line string literals are
> > deprecated", in two include/asm-i386 files.  Patches cleanly for at least
> > 2.4.10 and 2.4.12, and tested in 2.4.10.
> 
> Please reject this patch.  The gcc folks are wrong in this case.

Im curious - why do you make that specific claim. The multiline literals are
rather ugly.

Alan

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[Benjamin LaHaise]

On Mon, Oct 22, 2001 at 09:45:36PM +0100, Alan Cox wrote:
> > On Mon, Oct 22, 2001 at 01:05:10PM -0700, John Hawkes wrote:
> > > This patch eliminates gcc 3.0.1 warnings, "multi-line string literals are
> > > deprecated", in two include/asm-i386 files.  Patches cleanly for at least
> > > 2.4.10 and 2.4.12, and tested in 2.4.10.
> > 
> > Please reject this patch.  The gcc folks are wrong in this case.
> 
> Im curious - why do you make that specific claim. The multiline literals are
> rather ugly.

Which of the following is more readable:

/* try atomic lock inline, if that fails, spin out of line */
	"\tbtsl $1,%0\n"
	"\tbne 2f\n"
	"1:\n"
	"\t.section .text.lock\n\n"
	"\t2:\tcmpl $0,%0\n"
	"\tbne 2b\n"
	"\trep ; nop\n"
	"\tjmpl 1b\n\n"
	"\t.section .previous\n"

or:

/* try atomic lock inline, if that fails, spin out of line */
"	btsl $1,%0
1:
	.section .text.lock

2:	cmpl $0,%0
	bne 2b
	jmpl 1b

	.section .previous"

or:
	while (unlikely(test_and_set_bit(1, lock))) {
		while (lock.value)
			arch_pause();
	}

Ooops, sorry, ignore 3 -- that's only possible in a world where there is 
intrinsic support in the compiler to generate the assembly we're aiming 
for.  But of the two assembly versions, I think the second is much more 
readable.  The few gcc people I've spoken to locally about this agreed with 
me when I showed them some of the inline assembly bits in the two forms as 
above.

		-ben

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[David S. Miller]

   From: Benjamin LaHaise <bcrl@redhat.com>
   Date: Mon, 22 Oct 2001 16:51:57 -0400

   On Mon, Oct 22, 2001 at 09:45:36PM +0100, Alan Cox wrote:
   > > Please reject this patch.  The gcc folks are wrong in this case.
   > 
   > Im curious - why do you make that specific claim. The multiline literals are
   > rather ugly.
   
   Which of the following is more readable:
   
   /* try atomic lock inline, if that fails, spin out of line */
   	"\tbtsl $1,%0\n"

It's only gross because you decided to make it so, try:

   	"btsl $1,%0\n\t"

Which is what I use just about everywhere now and I'm prefectly
fine with it.

Franks a lot,
David S. Miller
davem@redhat.com

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[David Howells]

"David S. Miller" <davem@redhat.com> wrote:   
>   /* try atomic lock inline, if that fails, spin out of line */
>   	"\tbtsl $1,%0\n"
>
> It's only gross because you decided to make it so, try:
> 
>   	"btsl $1,%0\n\t"

You can also do things like:

	"    btsl   $1,%0		\n"
	"    bne    2f			\n"
	"1:				\n"
	"    .section .text.lock	\n"
	"				\n"
	"2:  cmpl $0,%0			\n"
	"    bne 2b			\n"
	"    rep ; nop			\n"
	"    jmpl 1b			\n"
	"				\n"
	"    .section .previous		\n"

using tabs or spaces to pad out the assembly.

David

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[Richard Henderson]

On Mon, Oct 22, 2001 at 04:51:57PM -0400, Benjamin LaHaise wrote:
> Which of the following is more readable:
[...]

Or (4):

	"btsl $0, %0		\n\
1:				\n\
	.section .text.lock	\n\
2:	cmpl $0,%0		\n\
	bne 2b			\n\
	jmpl 1b			\n\
	.previous"



r~

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[Benjamin LaHaise]

On Thu, Oct 25, 2001 at 12:11:50AM -0700, Richard Henderson wrote:
> On Mon, Oct 22, 2001 at 04:51:57PM -0400, Benjamin LaHaise wrote:
> > Which of the following is more readable:
> [...]
> 
> Or (4):
> 
> 	"btsl $0, %0		\n\

Is this a long term supported format?  It's certainly much better than 
the string per line, and if it's going to say around, then I'm willing 
to switch.

		-ben

Re: [PATCH] gcc 3.0.1 warnings about multi-line literals

[H. Peter Anvin]

Followup to:  <20011022161527.K23213@redhat.com>
By author:    Benjamin LaHaise <bcrl@redhat.com>
In newsgroup: linux.dev.kernel
>
> On Mon, Oct 22, 2001 at 01:05:10PM -0700, John Hawkes wrote:
> > This patch eliminates gcc 3.0.1 warnings, "multi-line string literals are
> > deprecated", in two include/asm-i386 files.  Patches cleanly for at least
> > 2.4.10 and 2.4.12, and tested in 2.4.10.
> 
> Please reject this patch.  The gcc folks are wrong in this case.
> 

It's not gcc even, it's C99 which are making these explicitly
deprecated.  If you want a string literal which includes \n and are
mapped in that form, do either:

       "foo\n"
       "bar\n"
       "baz\n"

... or ..

	"foo\n\
	bar\n\
	baz"

I usually do the former.

	-hpa
-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt	<amsp@zytor.com>