[Bug build/30098] Keep trying clang-format

["simark at simark dot ca" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=30098

Simon Marchi <simark at simark dot ca> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |simark at simark dot ca

--- Comment #6 from Simon Marchi <simark at simark dot ca> ---
Thanks for filing this.

Can we make some branch on sourceware with the latest attempt at doing this,
that we could update over time?  I would suggest to have just two commits over
master, one commit to add .clang-format (and maybe a script to run clang-format
correctly to do a mass reformat) and another commit that is the actual mass
reformat.

Using clang-format-15, I see some changes that are not stable in
hppa-netbsd-tdep.c, clang-format changes the code every time I run it:

diff --git a/gdb/hppa-netbsd-tdep.c b/gdb/hppa-netbsd-tdep.c
index 5468a135caf7..7b4c8c71fe2f 100644
--- a/gdb/hppa-netbsd-tdep.c
+++ b/gdb/hppa-netbsd-tdep.c
@@ -63,30 +63,29 @@ static void hppanbsd_sigtramp_cache_init (const struct
tramp_frame *,
                                          struct trad_frame_cache *,
                                          CORE_ADDR);

-static const struct tramp_frame hppanbsd_sigtramp_si4 = {
-  SIGTRAMP_FRAME,
-  4,
-  { { 0xc7d7c012, ULONGEST_MAX }, /*   bb,>=,n %arg3, 30, 1f           */
-    { 0xd6e01c1e, ULONGEST_MAX }, /*    depwi 0,31,2,%arg3             */
-    { 0x0ee81093, ULONGEST_MAX }, /*   ldw 4(%arg3), %r19              */
-    { 0x0ee01097, ULONGEST_MAX }, /*   ldw 0(%arg3), %arg3             */
-    /* 1:                                      */
-    { 0xe8404000, ULONGEST_MAX }, /*   blr %r0, %rp                    */
-    { 0xeae0c002, ULONGEST_MAX }, /*   bv,n %r0(%arg3)                 */
-    { 0x08000240, ULONGEST_MAX }, /*    nop                            */
-
-    { 0x0803025a, ULONGEST_MAX }, /*   copy %r3, %arg0                 */
-    { 0x20200801, ULONGEST_MAX }, /*   ldil -40000000, %r1             */
-    { 0xe420e008, ULONGEST_MAX }, /*   be,l 4(%sr7, %r1), %sr0, %r31   */
-    { 0x34160268, ULONGEST_MAX }, /*    ldi 134, %t1 ; SYS_setcontext  */
-
-    { 0x081c025a, ULONGEST_MAX }, /*   copy ret0, %arg0                */
-    { 0x20200801, ULONGEST_MAX }, /*   ldil -40000000, %r1             */
-    { 0xe420e008, ULONGEST_MAX }, /*   be,l 4(%sr7, %r1), %sr0, %r31   */
-    { 0x34160002, ULONGEST_MAX }, /*    ldi 1, %t1 ; SYS_exit          */
-    { TRAMP_SENTINEL_INSN, ULONGEST_MAX } },
-  hppanbsd_sigtramp_cache_init
-};
+static const struct tramp_frame hppanbsd_sigtramp_si4
+  = { SIGTRAMP_FRAME,
+      4,
+      { { 0xc7d7c012, ULONGEST_MAX }, /*       bb,>=,n %arg3, 30, 1f          
*/
+       { 0xd6e01c1e, ULONGEST_MAX }, /*         depwi 0,31,2,%arg3            
*/
+       { 0x0ee81093, ULONGEST_MAX }, /*        ldw 4(%arg3), %r19             
*/
+       { 0x0ee01097, ULONGEST_MAX }, /*        ldw 0(%arg3), %arg3            
*/
+       /* 1:                                   */
+       { 0xe8404000, ULONGEST_MAX }, /*        blr %r0, %rp                   
*/
+       { 0xeae0c002, ULONGEST_MAX }, /*        bv,n %r0(%arg3)                
*/
+       { 0x08000240, ULONGEST_MAX }, /*         nop                           
*/
+
+       { 0x0803025a, ULONGEST_MAX }, /*        copy %r3, %arg0                
*/
+       { 0x20200801, ULONGEST_MAX }, /*        ldil -40000000, %r1            
*/
+       { 0xe420e008, ULONGEST_MAX }, /*        be,l 4(%sr7, %r1), %sr0, %r31  
*/
+       { 0x34160268, ULONGEST_MAX }, /*         ldi 134, %t1 ; SYS_setcontext 
*/
+
+       { 0x081c025a, ULONGEST_MAX }, /*        copy ret0, %arg0               
*/
+       { 0x20200801, ULONGEST_MAX }, /*        ldil -40000000, %r1            
*/
+       { 0xe420e008, ULONGEST_MAX }, /*        be,l 4(%sr7, %r1), %sr0, %r31  
*/
+       { 0x34160002, ULONGEST_MAX }, /*         ldi 1, %t1 ; SYS_exit         
*/
+       { TRAMP_SENTINEL_INSN, ULONGEST_MAX } },
+      hppanbsd_sigtramp_cache_init };

Probably a bug in clang-format?  I guess that could be worked around by placing
markers around that code to prevent clang-format from touching it.

In my .clang-format, I had `UseTab: Always`, but it doesn't seem to make a
difference compared to what you have.


> Sometimes clang-format makes bad decisions.  One example
> I'm looking at is if you have an 'if' that is a series of
> clauses joined by '&&', sometimes it is clearest to put
> each such clause on its own line.  However clang-format does this:
> 
> @@ -194,10 +193,8 @@ eq_bfd (const void *a, const void *b)
>      = (const struct gdb_bfd_cache_search *) b;
>    struct gdb_bfd_data *gdata = (struct gdb_bfd_data *) bfd_usrdata (abfd);
>  
> -  return (gdata->mtime == s->mtime
> -	  && gdata->size == s->size
> -	  && gdata->inode == s->inode
> -	  && gdata->device_id == s->device_id
> +  return (gdata->mtime == s->mtime && gdata->size == s->size
> +	  && gdata->inode == s->inode && gdata->device_id == s->device_id
>  	  && strcmp (bfd_get_filename (abfd), s->filename) == 0);
>  }

I agree that the old one is more readable.  I suppose that could be a
clang-format rule, similar to BinPackParameters.  If an expression fits on one
line, leave it on one line.  Otherwise, break at binary operators.  It could
happen with other operators too, like:

 something = (aaaaaaaa + bbbbbbbb + cccccccc
              + dddddddd); 

vs

 something = (aaaaaaaa
              + bbbbbbbb
              + cccccccc
              + dddddddd);

Of course, humans will pretty much always make better decisions for things like
this.  For instance, you might want to have it organized logically like this:

 path = (base
         + "/" + subdir1
         + "/" + subdir2
         + "/" + subdir3);

But the tool will either choose:


 path = (base + "/" + subdir1 + "/"
         + subdir2 + "/" + subdir3);

of

 path = (base
         + "/"
         + subdir1
         + "/"
         + subdir2
         + "/"
         + subdir3);

If we want to use an automated tool, we have to accept the tradeoff that some
cases will be less nice, in exchange for convenience.

-- 
You are receiving this mail because:
You are on the CC list for the bug.