[PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[Jinyang He]

When I tried "./ld-new sth." the relax does not work because the
elf_seg_map (info->output_bfd) was NULL in loongarch_elf_relax_section.
There is no need for the segment info, we can get the address through
the section info. Thus, remove this condition.

bfd/ChangeLog:

	* elfnn-loongarch.c (loongarch_elf_relax_section): Remove
	elf_seg_map condition.

ld/ChangeLog:

	* testsuite/ld-loongarch-elf/relax.exp: Update trigger method.
	* testsuite/ld-loongarch-elf/relax.dd: New test.
---
 bfd/elfnn-loongarch.c                   |  1 -
 ld/testsuite/ld-loongarch-elf/relax.dd  |  6 +++++
 ld/testsuite/ld-loongarch-elf/relax.exp | 35 +++++++------------------
 3 files changed, 16 insertions(+), 26 deletions(-)
 create mode 100644 ld/testsuite/ld-loongarch-elf/relax.dd

diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
index d3d8419d8..01f349a24 100644
--- a/bfd/elfnn-loongarch.c
+++ b/bfd/elfnn-loongarch.c
@@ -3845,7 +3845,6 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
       || sec->sec_flg0
       || (sec->flags & SEC_RELOC) == 0
       || sec->reloc_count == 0
-      || elf_seg_map (info->output_bfd) == NULL
       || (info->disable_target_specific_optimizations
 	  && info->relax_pass == 0)
       /* The exp_seg_relro_adjust is enum phase_enum (0x4),
diff --git a/ld/testsuite/ld-loongarch-elf/relax.dd b/ld/testsuite/ld-loongarch-elf/relax.dd
new file mode 100644
index 000000000..e266beb8f
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax.dd
@@ -0,0 +1,6 @@
+#...
+.*pcaddi.*
+.*ld.w.*
+.*pcaddi.*
+.*ld.w.*
+#pass
diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp b/ld/testsuite/ld-loongarch-elf/relax.exp
index 7ff876d79..d2bb967c6 100644
--- a/ld/testsuite/ld-loongarch-elf/relax.exp
+++ b/ld/testsuite/ld-loongarch-elf/relax.exp
@@ -21,31 +21,6 @@
 
 if [istarget loongarch64-*-*] {
 
-  if [isbuild loongarch64-*-*] {
-    set testname "loongarch relax build"
-    set pre_builds [list \
-      [list \
-	"$testname" \
-	"" \
-	"" \
-	{relax.s} \
-	{} \
-	"relax" \
-      ] \
-    ]
-
-    run_cc_link_tests $pre_builds
-
-    if [file exist "tmpdir/relax"] {
-      set objdump_output [run_host_cmd "objdump" "-d tmpdir/relax"]
-      if { [ regexp ".*pcaddi.*pcaddi.*" $objdump_output] } {
-	pass "loongarch relax"
-      } {
-	fail "loongarch relax"
-      }
-    }
-  }
-
   run_ld_link_tests \
       [list \
 	  [list \
@@ -58,6 +33,16 @@ if [istarget loongarch64-*-*] {
 	      ] \
 	      "relax-align" \
 	  ] \
+	  [list \
+	      "relax" \
+	      "-e 0 -Ttext 0x10000 -Tdata 0x20000" "" \
+	      "" \
+	      {relax.s} \
+	      [list \
+		  [list objdump -d relax.dd] \
+	      ] \
+	      "relax" \
+	  ] \
       ]
 
   set objdump_flags "-s -j .data"
-- 
2.33.0

[PATCH 2/2] LoongArch: bfd: Add counter to get real relax region

[Jinyang He]

The relax action, loongarch_relax_pcala_addi and loongarch_relax_align,
may reduce the pc value of later instructions. Add counter to count
the number of bytes or instructions deleted. And recalculate the relax
region in loongarch_relax_pcala_addi.

bfd/ChangeLog:

	* elfnn-loongarch.c (loongarch_elf_relax_section): Add vars
	to count the deleted instructions and the maximum number of
	instructions that may be deleted due to R_LARCH_ALIGN.
	(loongarch_relax_pcala_addi): Adjust the relax decision range.

ld/ChangeLog:

	* testsuite/ld-loongarch-elf/relax.exp: Add test.
	* testsuite/ld-loongarch-elf/relax-edge1.s: New test.
	* testsuite/ld-loongarch-elf/relax-edge2.s: New test.
	* testsuite/ld-loongarch-elf/relax-edge1.dd: New test.
	* testsuite/ld-loongarch-elf/relax-edge2.dd: New test.
---
 bfd/elfnn-loongarch.c                        | 31 +++++++++++++++-----
 ld/testsuite/ld-loongarch-elf/relax-edge1.dd |  6 ++++
 ld/testsuite/ld-loongarch-elf/relax-edge1.s  | 25 ++++++++++++++++
 ld/testsuite/ld-loongarch-elf/relax-edge2.dd |  8 +++++
 ld/testsuite/ld-loongarch-elf/relax-edge2.s  | 15 ++++++++++
 ld/testsuite/ld-loongarch-elf/relax.exp      | 20 +++++++++++++
 6 files changed, 98 insertions(+), 7 deletions(-)
 create mode 100644 ld/testsuite/ld-loongarch-elf/relax-edge1.dd
 create mode 100644 ld/testsuite/ld-loongarch-elf/relax-edge1.s
 create mode 100644 ld/testsuite/ld-loongarch-elf/relax-edge2.dd
 create mode 100644 ld/testsuite/ld-loongarch-elf/relax-edge2.s

diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
index 01f349a24..52f8ab764 100644
--- a/bfd/elfnn-loongarch.c
+++ b/bfd/elfnn-loongarch.c
@@ -3700,16 +3700,19 @@ loongarch_relax_delete_bytes (bfd *abfd,
 /* Relax pcalau12i,addi.d => pcaddi.  */
 static bool
 loongarch_relax_pcala_addi (bfd *abfd, asection *sec,
-		       Elf_Internal_Rela *rel_hi, bfd_vma symval)
+		       Elf_Internal_Rela *rel_hi, bfd_vma symval,
+		       uint32_t align_max_deleted, uint32_t *pcnt_deleted)
 {
   bfd_byte *contents = elf_section_data (sec)->this_hdr.contents;
   Elf_Internal_Rela *rel_lo = rel_hi + 2;
   uint32_t pca = bfd_get (32, abfd, contents + rel_hi->r_offset);
   uint32_t add = bfd_get (32, abfd, contents + rel_lo->r_offset);
   uint32_t rd = pca & 0x1f;
-  bfd_vma pc = sec_addr (sec) + rel_hi->r_offset;
+  bfd_vma pc = sec_addr (sec) + rel_hi->r_offset - *pcnt_deleted * 4;
   const uint32_t addi_d = 0x02c00000;
   const uint32_t pcaddi = 0x18000000;
+  bfd_signed_vma low = (bfd_signed_vma)(int32_t)0xffe00000;
+  bfd_signed_vma high = (bfd_signed_vma)(int32_t)0x1ffffc - align_max_deleted;
 
   /* Is pcalau12i + addi.d insns?  */
   if ((ELFNN_R_TYPE (rel_lo->r_info) != R_LARCH_PCALA_LO12)
@@ -3722,8 +3725,8 @@ loongarch_relax_pcala_addi (bfd *abfd, asection *sec,
       || (((add >> 5) & 0x1f) != rd)
       /* Can be relaxed to pcaddi?  */
       || (symval & 0x3) /* 4 bytes align.  */
-      || ((bfd_signed_vma)(symval - pc) < (bfd_signed_vma)(int32_t)0xffe00000)
-      || ((bfd_signed_vma)(symval - pc) > (bfd_signed_vma)(int32_t)0x1ffffc))
+      || ((bfd_signed_vma)(symval - pc) < low)
+      || ((bfd_signed_vma)(symval - pc) > high))
     return false;
 
   pca = pcaddi | rd;
@@ -3734,6 +3737,7 @@ loongarch_relax_pcala_addi (bfd *abfd, asection *sec,
 				 R_LARCH_PCREL20_S2);
   rel_lo->r_info = ELFNN_R_INFO (ELFNN_R_SYM (rel_hi->r_info),
 				 R_LARCH_DELETE);
+  (*pcnt_deleted) += 1;
 
   return true;
 }
@@ -3840,6 +3844,7 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
   struct bfd_elf_section_data *data = elf_section_data (sec);
   Elf_Internal_Rela *relocs;
   *again = false;
+  uint32_t cnt_deleted = 0, align_max_deleted = 0;
 
   if (bfd_link_relocatable (info)
       || sec->sec_flg0
@@ -3881,6 +3886,7 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
       bool local_got = false;
       char symtype;
       struct elf_link_hash_entry *h = NULL;
+      bool relaxed = false;
 
       if (r_symndx < symtab_hdr->sh_info)
 	{
@@ -3954,6 +3960,8 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
 	case R_LARCH_ALIGN:
 	  if (2 == info->relax_pass)
 	    loongarch_relax_align (abfd, sec, sym_sec, info, rel, symval);
+	  else if (0 == info->relax_pass)
+	    align_max_deleted += rel->r_addend;
 	  break;
 	case R_LARCH_DELETE:
 	  if (info->relax_pass == 1)
@@ -3961,23 +3969,32 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
 	      loongarch_relax_delete_bytes (abfd, sec, rel->r_offset, 4, info);
 	      rel->r_info = ELFNN_R_INFO (0, R_LARCH_NONE);
 	    }
+	  else if (0 == info->relax_pass)
+	    cnt_deleted += 1;
 	  break;
 	case R_LARCH_PCALA_HI20:
 	  if (info->relax_pass == 0)
 	    {
 	      if (i + 4 > sec->reloc_count)
 		break;
-	      loongarch_relax_pcala_addi (abfd, sec, rel, symval);
+	      relaxed = loongarch_relax_pcala_addi (abfd, sec, rel, symval,
+						    align_max_deleted, &cnt_deleted);
+	      /* Skip the next R_LARCH_{RELAX, PCALA_LO12, RELAX} relocs. */
+	      if (relaxed)
+		i += 3;
 	    }
 	  break;
 	case R_LARCH_GOT_PC_HI20:
-	  if (local_got)
+	  if (info->relax_pass == 0 && local_got)
 	    {
 	      if (i + 4 > sec->reloc_count)
 		break;
 	      if (loongarch_relax_pcala_ld (abfd, sec, rel))
 		{
-		  loongarch_relax_pcala_addi (abfd, sec, rel, symval);
+		  relaxed = loongarch_relax_pcala_addi (abfd, sec, rel, symval,
+							align_max_deleted, &cnt_deleted);
+		  if (relaxed)
+		    i += 3;
 		}
 	    }
 	  break;
diff --git a/ld/testsuite/ld-loongarch-elf/relax-edge1.dd b/ld/testsuite/ld-loongarch-elf/relax-edge1.dd
new file mode 100644
index 000000000..92836e679
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-edge1.dd
@@ -0,0 +1,6 @@
+#...
+.*pcaddi.*
+.*pcalau12i.*
+.*addi.*
+.*pcaddi.*
+#pass
diff --git a/ld/testsuite/ld-loongarch-elf/relax-edge1.s b/ld/testsuite/ld-loongarch-elf/relax-edge1.s
new file mode 100644
index 000000000..df16c1384
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-edge1.s
@@ -0,0 +1,25 @@
+  .data
+  .type obj1, @object
+obj1:
+  .word 0
+  .size obj1, .-obj1
+
+  .space 8
+
+  .type obj2, @object
+obj2:
+  .word 0
+  .size obj2, .-obj2
+
+  .text
+main:
+  la.local $a0, obj1
+  la.local $a0, obj3
+  la.local $a0, obj2
+
+  .bss
+  .space 0x4
+  .type obj3, @object
+obj3:
+  .word 0
+  .size obj3, .-obj3
diff --git a/ld/testsuite/ld-loongarch-elf/relax-edge2.dd b/ld/testsuite/ld-loongarch-elf/relax-edge2.dd
new file mode 100644
index 000000000..5610cc8ed
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-edge2.dd
@@ -0,0 +1,8 @@
+#...
+.*nop.*
+.*nop.*
+.*nop.*
+.*nop.*
+.*pcalau12i.*
+.*addi.*
+#pass
diff --git a/ld/testsuite/ld-loongarch-elf/relax-edge2.s b/ld/testsuite/ld-loongarch-elf/relax-edge2.s
new file mode 100644
index 000000000..c2a42e705
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-edge2.s
@@ -0,0 +1,15 @@
+  .text
+main:
+  nop
+  nop
+  nop
+  nop
+  .align 4
+  la.local $a0, obj1
+
+  .data
+  .space 0x10
+  .type obj1, @object
+obj1:
+  .word 0
+  .size obj1, .-obj1
diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp b/ld/testsuite/ld-loongarch-elf/relax.exp
index d2bb967c6..19ade4970 100644
--- a/ld/testsuite/ld-loongarch-elf/relax.exp
+++ b/ld/testsuite/ld-loongarch-elf/relax.exp
@@ -43,6 +43,26 @@ if [istarget loongarch64-*-*] {
 	      ] \
 	      "relax" \
 	  ] \
+	  [list \
+	      "relax-edge1" \
+	      "-e 0 -Ttext 0x400000 -Tdata 0x200000 -Tbss 0x600000" "" \
+	      "" \
+	      {relax-edge1.s} \
+	      [list \
+		  [list objdump -d relax-edge1.dd] \
+	      ] \
+	      "relax-edge1" \
+	  ] \
+	  [list \
+	      "relax-edge2" \
+	      "-e 0 -Ttext 0x400000 -Tdata 0x600000" "" \
+	      "" \
+	      {relax-edge2.s} \
+	      [list \
+		  [list objdump -d relax-edge2.dd] \
+	      ] \
+	      "relax-edge2" \
+	  ] \
       ]
 
   set objdump_flags "-s -j .data"
-- 
2.33.0

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[mengqinggang]

Hi,

Without this condition, the value of 'symbol - pc' may be differences 
between
loongarch_elf_relax_section and  loongarch_elf_relocate_section.
And it will cause some spec2006 test errors.

在 2023/7/11 下午4:49, Jinyang He 写道:
> When I tried "./ld-new sth." the relax does not work because the
> elf_seg_map (info->output_bfd) was NULL in loongarch_elf_relax_section.
> There is no need for the segment info, we can get the address through
> the section info. Thus, remove this condition.
>
> bfd/ChangeLog:
>
> 	* elfnn-loongarch.c (loongarch_elf_relax_section): Remove
> 	elf_seg_map condition.
>
> ld/ChangeLog:
>
> 	* testsuite/ld-loongarch-elf/relax.exp: Update trigger method.
> 	* testsuite/ld-loongarch-elf/relax.dd: New test.
> ---
>   bfd/elfnn-loongarch.c                   |  1 -
>   ld/testsuite/ld-loongarch-elf/relax.dd  |  6 +++++
>   ld/testsuite/ld-loongarch-elf/relax.exp | 35 +++++++------------------
>   3 files changed, 16 insertions(+), 26 deletions(-)
>   create mode 100644 ld/testsuite/ld-loongarch-elf/relax.dd
>
> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
> index d3d8419d8..01f349a24 100644
> --- a/bfd/elfnn-loongarch.c
> +++ b/bfd/elfnn-loongarch.c
> @@ -3845,7 +3845,6 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
>         || sec->sec_flg0
>         || (sec->flags & SEC_RELOC) == 0
>         || sec->reloc_count == 0
> -      || elf_seg_map (info->output_bfd) == NULL
>         || (info->disable_target_specific_optimizations
>   	  && info->relax_pass == 0)
>         /* The exp_seg_relro_adjust is enum phase_enum (0x4),
> diff --git a/ld/testsuite/ld-loongarch-elf/relax.dd b/ld/testsuite/ld-loongarch-elf/relax.dd
> new file mode 100644
> index 000000000..e266beb8f
> --- /dev/null
> +++ b/ld/testsuite/ld-loongarch-elf/relax.dd
> @@ -0,0 +1,6 @@
> +#...
> +.*pcaddi.*
> +.*ld.w.*
> +.*pcaddi.*
> +.*ld.w.*
> +#pass
> diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp b/ld/testsuite/ld-loongarch-elf/relax.exp
> index 7ff876d79..d2bb967c6 100644
> --- a/ld/testsuite/ld-loongarch-elf/relax.exp
> +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
> @@ -21,31 +21,6 @@
>   
>   if [istarget loongarch64-*-*] {
>   
> -  if [isbuild loongarch64-*-*] {
> -    set testname "loongarch relax build"
> -    set pre_builds [list \
> -      [list \
> -	"$testname" \
> -	"" \
> -	"" \
> -	{relax.s} \
> -	{} \
> -	"relax" \
> -      ] \
> -    ]
> -
> -    run_cc_link_tests $pre_builds
> -
> -    if [file exist "tmpdir/relax"] {
> -      set objdump_output [run_host_cmd "objdump" "-d tmpdir/relax"]
> -      if { [ regexp ".*pcaddi.*pcaddi.*" $objdump_output] } {
> -	pass "loongarch relax"
> -      } {
> -	fail "loongarch relax"
> -      }
> -    }
> -  }
> -
>     run_ld_link_tests \
>         [list \
>   	  [list \
> @@ -58,6 +33,16 @@ if [istarget loongarch64-*-*] {
>   	      ] \
>   	      "relax-align" \
>   	  ] \
> +	  [list \
> +	      "relax" \
> +	      "-e 0 -Ttext 0x10000 -Tdata 0x20000" "" \
> +	      "" \
> +	      {relax.s} \
> +	      [list \
> +		  [list objdump -d relax.dd] \
> +	      ] \
> +	      "relax" \
> +	  ] \
>         ]
>   
>     set objdump_flags "-s -j .data"

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[Jinyang He]

Hi,


I'm not fimiliar with the process of output binary. I just noted that it 
calls lang_relax_sections() before calling 
_bfd_elf_map_sections_to_segments() in ldelf_map_segments(). Thus I 
think the condition, elf_seg_map (info->output_bfd) == NULL, always be 
true when first time it calls loongarch_elf_relax_section(). Actually we 
can get right symbol value when relaxation, but ...

You reminder me that the symbol value will be reduced due to relaxation, 
which like the instruction pc is reduced. Then we cannot get right 
symbol value if the symbol in relaxable section. And I write a test,

$ cat c.s
     .section ".another.text", "x"
     nop
     la.local $a0, sym1
sym2:
     nop

     .text
sym1:
     nop
     nop
     nop
     la.local $a0, sym2

$ ./gas/as-new -mabi=lp64d -o c.o c.s
$ ./ld/ld-new c.o -o c -e 0 --section-start=.another.text=0x120000000 
-Ttext 0x120200000

Disassembly of section .another.text:

0000000120000000 <sym2-0x8>:
    120000000:    03400000     andi            $zero, $zero, 0x0
    120000004:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)

0000000120000008 <sym2>:
    120000008:    03400000     andi            $zero, $zero, 0x0

Disassembly of section .text:

0000000120200000 <sym1>:
    120200000:    03400000     andi            $zero, $zero, 0x0
    120200004:    03400000     andi            $zero, $zero, 0x0
    120200008:    03400000     andi            $zero, $zero, 0x0
    12020000c:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)

Due to the bug repaired by Patch2 and the bug reported by this test. And 
I also did not see that condition in other archs. I'm not sure that the 
relaxation spec2006 error is caused by that condition or those bugs.


On 2023-07-12 14:35, mengqinggang wrote:
> Hi,
>
> Without this condition, the value of 'symbol - pc' may be differences 
> between
> loongarch_elf_relax_section and  loongarch_elf_relocate_section.
> And it will cause some spec2006 test errors.
>
> 在 2023/7/11 下午4:49, Jinyang He 写道:
>> When I tried "./ld-new sth." the relax does not work because the
>> elf_seg_map (info->output_bfd) was NULL in loongarch_elf_relax_section.
>> There is no need for the segment info, we can get the address through
>> the section info. Thus, remove this condition.
>>
>> bfd/ChangeLog:
>>
>>     * elfnn-loongarch.c (loongarch_elf_relax_section): Remove
>>     elf_seg_map condition.
>>
>> ld/ChangeLog:
>>
>>     * testsuite/ld-loongarch-elf/relax.exp: Update trigger method.
>>     * testsuite/ld-loongarch-elf/relax.dd: New test.
>> ---
>>   bfd/elfnn-loongarch.c                   |  1 -
>>   ld/testsuite/ld-loongarch-elf/relax.dd  |  6 +++++
>>   ld/testsuite/ld-loongarch-elf/relax.exp | 35 +++++++------------------
>>   3 files changed, 16 insertions(+), 26 deletions(-)
>>   create mode 100644 ld/testsuite/ld-loongarch-elf/relax.dd
>>
>> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
>> index d3d8419d8..01f349a24 100644
>> --- a/bfd/elfnn-loongarch.c
>> +++ b/bfd/elfnn-loongarch.c
>> @@ -3845,7 +3845,6 @@ loongarch_elf_relax_section (bfd *abfd, 
>> asection *sec,
>>         || sec->sec_flg0
>>         || (sec->flags & SEC_RELOC) == 0
>>         || sec->reloc_count == 0
>> -      || elf_seg_map (info->output_bfd) == NULL
>>         || (info->disable_target_specific_optimizations
>>         && info->relax_pass == 0)
>>         /* The exp_seg_relro_adjust is enum phase_enum (0x4),
>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.dd 
>> b/ld/testsuite/ld-loongarch-elf/relax.dd
>> new file mode 100644
>> index 000000000..e266beb8f
>> --- /dev/null
>> +++ b/ld/testsuite/ld-loongarch-elf/relax.dd
>> @@ -0,0 +1,6 @@
>> +#...
>> +.*pcaddi.*
>> +.*ld.w.*
>> +.*pcaddi.*
>> +.*ld.w.*
>> +#pass
>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp 
>> b/ld/testsuite/ld-loongarch-elf/relax.exp
>> index 7ff876d79..d2bb967c6 100644
>> --- a/ld/testsuite/ld-loongarch-elf/relax.exp
>> +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
>> @@ -21,31 +21,6 @@
>>     if [istarget loongarch64-*-*] {
>>   -  if [isbuild loongarch64-*-*] {
>> -    set testname "loongarch relax build"
>> -    set pre_builds [list \
>> -      [list \
>> -    "$testname" \
>> -    "" \
>> -    "" \
>> -    {relax.s} \
>> -    {} \
>> -    "relax" \
>> -      ] \
>> -    ]
>> -
>> -    run_cc_link_tests $pre_builds
>> -
>> -    if [file exist "tmpdir/relax"] {
>> -      set objdump_output [run_host_cmd "objdump" "-d tmpdir/relax"]
>> -      if { [ regexp ".*pcaddi.*pcaddi.*" $objdump_output] } {
>> -    pass "loongarch relax"
>> -      } {
>> -    fail "loongarch relax"
>> -      }
>> -    }
>> -  }
>> -
>>     run_ld_link_tests \
>>         [list \
>>         [list \
>> @@ -58,6 +33,16 @@ if [istarget loongarch64-*-*] {
>>             ] \
>>             "relax-align" \
>>         ] \
>> +      [list \
>> +          "relax" \
>> +          "-e 0 -Ttext 0x10000 -Tdata 0x20000" "" \
>> +          "" \
>> +          {relax.s} \
>> +          [list \
>> +          [list objdump -d relax.dd] \
>> +          ] \
>> +          "relax" \
>> +      ] \
>>         ]
>>       set objdump_flags "-s -j .data"

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[mengqinggang]

Hi,

I will apply this two patches to see if there are any errors in specc2006.

在 2023/7/12 下午4:08, Jinyang He 写道:
> Hi,
>
>
> I'm not fimiliar with the process of output binary. I just noted that 
> it calls lang_relax_sections() before calling 
> _bfd_elf_map_sections_to_segments() in ldelf_map_segments(). Thus I 
> think the condition, elf_seg_map (info->output_bfd) == NULL, always be 
> true when first time it calls loongarch_elf_relax_section(). Actually 
> we can get right symbol value when relaxation, but ...
>
> You reminder me that the symbol value will be reduced due to 
> relaxation, which like the instruction pc is reduced. Then we cannot 
> get right symbol value if the symbol in relaxable section. And I write 
> a test,
>
> $ cat c.s
>     .section ".another.text", "x"
>     nop
>     la.local $a0, sym1
> sym2:
>     nop
>
>     .text
> sym1:
>     nop
>     nop
>     nop
>     la.local $a0, sym2
>
> $ ./gas/as-new -mabi=lp64d -o c.o c.s
> $ ./ld/ld-new c.o -o c -e 0 --section-start=.another.text=0x120000000 
> -Ttext 0x120200000
>
> Disassembly of section .another.text:
>
> 0000000120000000 <sym2-0x8>:
>    120000000:    03400000     andi            $zero, $zero, 0x0
>    120000004:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
>
> 0000000120000008 <sym2>:
>    120000008:    03400000     andi            $zero, $zero, 0x0
>
> Disassembly of section .text:
>
> 0000000120200000 <sym1>:
>    120200000:    03400000     andi            $zero, $zero, 0x0
>    120200004:    03400000     andi            $zero, $zero, 0x0
>    120200008:    03400000     andi            $zero, $zero, 0x0
>    12020000c:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
>
> Due to the bug repaired by Patch2 and the bug reported by this test. 
> And I also did not see that condition in other archs. I'm not sure 
> that the relaxation spec2006 error is caused by that condition or 
> those bugs.
>
>
> On 2023-07-12 14:35, mengqinggang wrote:
>> Hi,
>>
>> Without this condition, the value of 'symbol - pc' may be differences 
>> between
>> loongarch_elf_relax_section and  loongarch_elf_relocate_section.
>> And it will cause some spec2006 test errors.
>>
>> 在 2023/7/11 下午4:49, Jinyang He 写道:
>>> When I tried "./ld-new sth." the relax does not work because the
>>> elf_seg_map (info->output_bfd) was NULL in loongarch_elf_relax_section.
>>> There is no need for the segment info, we can get the address through
>>> the section info. Thus, remove this condition.
>>>
>>> bfd/ChangeLog:
>>>
>>>     * elfnn-loongarch.c (loongarch_elf_relax_section): Remove
>>>     elf_seg_map condition.
>>>
>>> ld/ChangeLog:
>>>
>>>     * testsuite/ld-loongarch-elf/relax.exp: Update trigger method.
>>>     * testsuite/ld-loongarch-elf/relax.dd: New test.
>>> ---
>>>   bfd/elfnn-loongarch.c                   |  1 -
>>>   ld/testsuite/ld-loongarch-elf/relax.dd  |  6 +++++
>>>   ld/testsuite/ld-loongarch-elf/relax.exp | 35 
>>> +++++++------------------
>>>   3 files changed, 16 insertions(+), 26 deletions(-)
>>>   create mode 100644 ld/testsuite/ld-loongarch-elf/relax.dd
>>>
>>> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
>>> index d3d8419d8..01f349a24 100644
>>> --- a/bfd/elfnn-loongarch.c
>>> +++ b/bfd/elfnn-loongarch.c
>>> @@ -3845,7 +3845,6 @@ loongarch_elf_relax_section (bfd *abfd, 
>>> asection *sec,
>>>         || sec->sec_flg0
>>>         || (sec->flags & SEC_RELOC) == 0
>>>         || sec->reloc_count == 0
>>> -      || elf_seg_map (info->output_bfd) == NULL
>>>         || (info->disable_target_specific_optimizations
>>>         && info->relax_pass == 0)
>>>         /* The exp_seg_relro_adjust is enum phase_enum (0x4),
>>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.dd 
>>> b/ld/testsuite/ld-loongarch-elf/relax.dd
>>> new file mode 100644
>>> index 000000000..e266beb8f
>>> --- /dev/null
>>> +++ b/ld/testsuite/ld-loongarch-elf/relax.dd
>>> @@ -0,0 +1,6 @@
>>> +#...
>>> +.*pcaddi.*
>>> +.*ld.w.*
>>> +.*pcaddi.*
>>> +.*ld.w.*
>>> +#pass
>>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp 
>>> b/ld/testsuite/ld-loongarch-elf/relax.exp
>>> index 7ff876d79..d2bb967c6 100644
>>> --- a/ld/testsuite/ld-loongarch-elf/relax.exp
>>> +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
>>> @@ -21,31 +21,6 @@
>>>     if [istarget loongarch64-*-*] {
>>>   -  if [isbuild loongarch64-*-*] {
>>> -    set testname "loongarch relax build"
>>> -    set pre_builds [list \
>>> -      [list \
>>> -    "$testname" \
>>> -    "" \
>>> -    "" \
>>> -    {relax.s} \
>>> -    {} \
>>> -    "relax" \
>>> -      ] \
>>> -    ]
>>> -
>>> -    run_cc_link_tests $pre_builds
>>> -
>>> -    if [file exist "tmpdir/relax"] {
>>> -      set objdump_output [run_host_cmd "objdump" "-d tmpdir/relax"]
>>> -      if { [ regexp ".*pcaddi.*pcaddi.*" $objdump_output] } {
>>> -    pass "loongarch relax"
>>> -      } {
>>> -    fail "loongarch relax"
>>> -      }
>>> -    }
>>> -  }
>>> -
>>>     run_ld_link_tests \
>>>         [list \
>>>         [list \
>>> @@ -58,6 +33,16 @@ if [istarget loongarch64-*-*] {
>>>             ] \
>>>             "relax-align" \
>>>         ] \
>>> +      [list \
>>> +          "relax" \
>>> +          "-e 0 -Ttext 0x10000 -Tdata 0x20000" "" \
>>> +          "" \
>>> +          {relax.s} \
>>> +          [list \
>>> +          [list objdump -d relax.dd] \
>>> +          ] \
>>> +          "relax" \
>>> +      ] \
>>>         ]
>>>       set objdump_flags "-s -j .data"

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[Jinyang He]

Hi,


We should pay attention to them, the bug in relaxation. Relaxation may 
not work correctly because of the bug1 reported by the second patch and 
the bug2 reported in the my previous email, although it works well in 
most of the time. Those 2 bugs are just what we've found, but there may 
be hidden problems.
I also tested the bug2 on RISCV and although it couldn't be resolved, it 
reported an error.

Test is,
$ cat c.s
   .section ".another.text", "x"
   .fill 1, 4, 0
   call fn2
   call fn2
fn1:
   nop

.text
fn2:
   .fill 4, 4, 0
   call fn1

$ ./gas/as-new  -march=rv32ic_zicsr -mno-arch-attr  -o c.o c.s
$ ./ld/ld-new c.o -o c -e 0 --section-start=.another.text=0x1000000 
-Ttext 0x1100000
c.o: in function `fn2':
(.text+0x10): relocation truncated to fit: R_RISCV_JAL against `fn1'

So, I'll find the reason why reloc_bits_pcrel20_s2() not reports the 
overfollow error, and add error report which I think it is more 
important than these two patches so that we can get feedback when we link.


Thanks!


On 2023-07-13 11:13, mengqinggang wrote:
> Hi,
>
> I will apply this two patches to see if there are any errors in 
> specc2006.
>
> 在 2023/7/12 下午4:08, Jinyang He 写道:
>> Hi,
>>
>>
>> I'm not fimiliar with the process of output binary. I just noted that 
>> it calls lang_relax_sections() before calling 
>> _bfd_elf_map_sections_to_segments() in ldelf_map_segments(). Thus I 
>> think the condition, elf_seg_map (info->output_bfd) == NULL, always 
>> be true when first time it calls loongarch_elf_relax_section(). 
>> Actually we can get right symbol value when relaxation, but ...
>>
>> You reminder me that the symbol value will be reduced due to 
>> relaxation, which like the instruction pc is reduced. Then we cannot 
>> get right symbol value if the symbol in relaxable section. And I 
>> write a test,
>>
>> $ cat c.s
>>     .section ".another.text", "x"
>>     nop
>>     la.local $a0, sym1
>> sym2:
>>     nop
>>
>>     .text
>> sym1:
>>     nop
>>     nop
>>     nop
>>     la.local $a0, sym2
>>
>> $ ./gas/as-new -mabi=lp64d -o c.o c.s
>> $ ./ld/ld-new c.o -o c -e 0 --section-start=.another.text=0x120000000 
>> -Ttext 0x120200000
>>
>> Disassembly of section .another.text:
>>
>> 0000000120000000 <sym2-0x8>:
>>    120000000:    03400000     andi            $zero, $zero, 0x0
>>    120000004:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
>>
>> 0000000120000008 <sym2>:
>>    120000008:    03400000     andi            $zero, $zero, 0x0
>>
>> Disassembly of section .text:
>>
>> 0000000120200000 <sym1>:
>>    120200000:    03400000     andi            $zero, $zero, 0x0
>>    120200004:    03400000     andi            $zero, $zero, 0x0
>>    120200008:    03400000     andi            $zero, $zero, 0x0
>>    12020000c:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
>>
>> Due to the bug repaired by Patch2 and the bug reported by this test. 
>> And I also did not see that condition in other archs. I'm not sure 
>> that the relaxation spec2006 error is caused by that condition or 
>> those bugs.
>>
>>
>> On 2023-07-12 14:35, mengqinggang wrote:
>>> Hi,
>>>
>>> Without this condition, the value of 'symbol - pc' may be 
>>> differences between
>>> loongarch_elf_relax_section and loongarch_elf_relocate_section.
>>> And it will cause some spec2006 test errors.
>>>
>>> 在 2023/7/11 下午4:49, Jinyang He 写道:
>>>> When I tried "./ld-new sth." the relax does not work because the
>>>> elf_seg_map (info->output_bfd) was NULL in 
>>>> loongarch_elf_relax_section.
>>>> There is no need for the segment info, we can get the address through
>>>> the section info. Thus, remove this condition.
>>>>
>>>> bfd/ChangeLog:
>>>>
>>>>     * elfnn-loongarch.c (loongarch_elf_relax_section): Remove
>>>>     elf_seg_map condition.
>>>>
>>>> ld/ChangeLog:
>>>>
>>>>     * testsuite/ld-loongarch-elf/relax.exp: Update trigger method.
>>>>     * testsuite/ld-loongarch-elf/relax.dd: New test.
>>>> ---
>>>>   bfd/elfnn-loongarch.c                   |  1 -
>>>>   ld/testsuite/ld-loongarch-elf/relax.dd  |  6 +++++
>>>>   ld/testsuite/ld-loongarch-elf/relax.exp | 35 
>>>> +++++++------------------
>>>>   3 files changed, 16 insertions(+), 26 deletions(-)
>>>>   create mode 100644 ld/testsuite/ld-loongarch-elf/relax.dd
>>>>
>>>> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
>>>> index d3d8419d8..01f349a24 100644
>>>> --- a/bfd/elfnn-loongarch.c
>>>> +++ b/bfd/elfnn-loongarch.c
>>>> @@ -3845,7 +3845,6 @@ loongarch_elf_relax_section (bfd *abfd, 
>>>> asection *sec,
>>>>         || sec->sec_flg0
>>>>         || (sec->flags & SEC_RELOC) == 0
>>>>         || sec->reloc_count == 0
>>>> -      || elf_seg_map (info->output_bfd) == NULL
>>>>         || (info->disable_target_specific_optimizations
>>>>         && info->relax_pass == 0)
>>>>         /* The exp_seg_relro_adjust is enum phase_enum (0x4),
>>>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.dd 
>>>> b/ld/testsuite/ld-loongarch-elf/relax.dd
>>>> new file mode 100644
>>>> index 000000000..e266beb8f
>>>> --- /dev/null
>>>> +++ b/ld/testsuite/ld-loongarch-elf/relax.dd
>>>> @@ -0,0 +1,6 @@
>>>> +#...
>>>> +.*pcaddi.*
>>>> +.*ld.w.*
>>>> +.*pcaddi.*
>>>> +.*ld.w.*
>>>> +#pass
>>>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp 
>>>> b/ld/testsuite/ld-loongarch-elf/relax.exp
>>>> index 7ff876d79..d2bb967c6 100644
>>>> --- a/ld/testsuite/ld-loongarch-elf/relax.exp
>>>> +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
>>>> @@ -21,31 +21,6 @@
>>>>     if [istarget loongarch64-*-*] {
>>>>   -  if [isbuild loongarch64-*-*] {
>>>> -    set testname "loongarch relax build"
>>>> -    set pre_builds [list \
>>>> -      [list \
>>>> -    "$testname" \
>>>> -    "" \
>>>> -    "" \
>>>> -    {relax.s} \
>>>> -    {} \
>>>> -    "relax" \
>>>> -      ] \
>>>> -    ]
>>>> -
>>>> -    run_cc_link_tests $pre_builds
>>>> -
>>>> -    if [file exist "tmpdir/relax"] {
>>>> -      set objdump_output [run_host_cmd "objdump" "-d tmpdir/relax"]
>>>> -      if { [ regexp ".*pcaddi.*pcaddi.*" $objdump_output] } {
>>>> -    pass "loongarch relax"
>>>> -      } {
>>>> -    fail "loongarch relax"
>>>> -      }
>>>> -    }
>>>> -  }
>>>> -
>>>>     run_ld_link_tests \
>>>>         [list \
>>>>         [list \
>>>> @@ -58,6 +33,16 @@ if [istarget loongarch64-*-*] {
>>>>             ] \
>>>>             "relax-align" \
>>>>         ] \
>>>> +      [list \
>>>> +          "relax" \
>>>> +          "-e 0 -Ttext 0x10000 -Tdata 0x20000" "" \
>>>> +          "" \
>>>> +          {relax.s} \
>>>> +          [list \
>>>> +          [list objdump -d relax.dd] \
>>>> +          ] \
>>>> +          "relax" \
>>>> +      ] \
>>>>         ]
>>>>       set objdump_flags "-s -j .data"

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[Jinyang He]

On 2023-07-13 15:19, Jinyang He wrote:

> Hi,
>
>
> We should pay attention to them, the bug in relaxation. Relaxation may 
> not work correctly because of the bug1 reported by the second patch 
> and the bug2 reported in the my previous email, although it works well 
> in most of the time. Those 2 bugs are just what we've found, but there 
> may be hidden problems.
> I also tested the bug2 on RISCV and although it couldn't be resolved, 
> it reported an error.
>
> Test is,
> $ cat c.s
>   .section ".another.text", "x"
>   .fill 1, 4, 0
>   call fn2
>   call fn2
> fn1:
>   nop
>
> .text
> fn2:
>   .fill 4, 4, 0
>   call fn1
>
> $ ./gas/as-new  -march=rv32ic_zicsr -mno-arch-attr  -o c.o c.s
> $ ./ld/ld-new c.o -o c -e 0 --section-start=.another.text=0x1000000 
> -Ttext 0x1100000
> c.o: in function `fn2':
> (.text+0x10): relocation truncated to fit: R_RISCV_JAL against `fn1'
>
> So, I'll find the reason why reloc_bits_pcrel20_s2() not reports the 
> overfollow error, and add error report which I think it is more 
> important than these two patches so that we can get feedback when we 
> link.
>

Now, I find that the sign-overflow-check has bug, include 
reloc_bits_pcrel20_s2(), reloc_bits_b26() and (others, I did not test 
them). And I think the "mask" should be
     bfd_signed_vma mask = ((bfd_signed_vma)0x1 << (howto->bitsize - 
(sign ? 1 : 0)) - 1;

The test about reloc_bits_b26() is,

$ cat d.s
         .section ".another.text", "x"
         b       sym1

         .text
         nop
sym1:
         nop

$ ./gas/as-new -mabi=lp64d -o d.o d.s
$ ./ld/ld-new d.o -o d -e 0 --section-start=.another.text=0x130000000 
-Ttext 0x120000000

I'll do fix and send v2 after you test spec2006. Or other responses?


Thanks!


>
> On 2023-07-13 11:13, mengqinggang wrote:
>> Hi,
>>
>> I will apply this two patches to see if there are any errors in 
>> specc2006.
>>
>> 在 2023/7/12 下午4:08, Jinyang He 写道:
>>> Hi,
>>>
>>>
>>> I'm not fimiliar with the process of output binary. I just noted 
>>> that it calls lang_relax_sections() before calling 
>>> _bfd_elf_map_sections_to_segments() in ldelf_map_segments(). Thus I 
>>> think the condition, elf_seg_map (info->output_bfd) == NULL, always 
>>> be true when first time it calls loongarch_elf_relax_section(). 
>>> Actually we can get right symbol value when relaxation, but ...
>>>
>>> You reminder me that the symbol value will be reduced due to 
>>> relaxation, which like the instruction pc is reduced. Then we cannot 
>>> get right symbol value if the symbol in relaxable section. And I 
>>> write a test,
>>>
>>> $ cat c.s
>>>     .section ".another.text", "x"
>>>     nop
>>>     la.local $a0, sym1
>>> sym2:
>>>     nop
>>>
>>>     .text
>>> sym1:
>>>     nop
>>>     nop
>>>     nop
>>>     la.local $a0, sym2
>>>
>>> $ ./gas/as-new -mabi=lp64d -o c.o c.s
>>> $ ./ld/ld-new c.o -o c -e 0 
>>> --section-start=.another.text=0x120000000 -Ttext 0x120200000
>>>
>>> Disassembly of section .another.text:
>>>
>>> 0000000120000000 <sym2-0x8>:
>>>    120000000:    03400000     andi            $zero, $zero, 0x0
>>>    120000004:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
>>>
>>> 0000000120000008 <sym2>:
>>>    120000008:    03400000     andi            $zero, $zero, 0x0
>>>
>>> Disassembly of section .text:
>>>
>>> 0000000120200000 <sym1>:
>>>    120200000:    03400000     andi            $zero, $zero, 0x0
>>>    120200004:    03400000     andi            $zero, $zero, 0x0
>>>    120200008:    03400000     andi            $zero, $zero, 0x0
>>>    12020000c:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
>>>
>>> Due to the bug repaired by Patch2 and the bug reported by this test. 
>>> And I also did not see that condition in other archs. I'm not sure 
>>> that the relaxation spec2006 error is caused by that condition or 
>>> those bugs.
>>>
>>>
>>> On 2023-07-12 14:35, mengqinggang wrote:
>>>> Hi,
>>>>
>>>> Without this condition, the value of 'symbol - pc' may be 
>>>> differences between
>>>> loongarch_elf_relax_section and loongarch_elf_relocate_section.
>>>> And it will cause some spec2006 test errors.
>>>>
>>>> 在 2023/7/11 下午4:49, Jinyang He 写道:
>>>>> When I tried "./ld-new sth." the relax does not work because the
>>>>> elf_seg_map (info->output_bfd) was NULL in 
>>>>> loongarch_elf_relax_section.
>>>>> There is no need for the segment info, we can get the address through
>>>>> the section info. Thus, remove this condition.
>>>>>
>>>>> bfd/ChangeLog:
>>>>>
>>>>>     * elfnn-loongarch.c (loongarch_elf_relax_section): Remove
>>>>>     elf_seg_map condition.
>>>>>
>>>>> ld/ChangeLog:
>>>>>
>>>>>     * testsuite/ld-loongarch-elf/relax.exp: Update trigger method.
>>>>>     * testsuite/ld-loongarch-elf/relax.dd: New test.
>>>>> ---
>>>>>   bfd/elfnn-loongarch.c                   |  1 -
>>>>>   ld/testsuite/ld-loongarch-elf/relax.dd  |  6 +++++
>>>>>   ld/testsuite/ld-loongarch-elf/relax.exp | 35 
>>>>> +++++++------------------
>>>>>   3 files changed, 16 insertions(+), 26 deletions(-)
>>>>>   create mode 100644 ld/testsuite/ld-loongarch-elf/relax.dd
>>>>>
>>>>> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
>>>>> index d3d8419d8..01f349a24 100644
>>>>> --- a/bfd/elfnn-loongarch.c
>>>>> +++ b/bfd/elfnn-loongarch.c
>>>>> @@ -3845,7 +3845,6 @@ loongarch_elf_relax_section (bfd *abfd, 
>>>>> asection *sec,
>>>>>         || sec->sec_flg0
>>>>>         || (sec->flags & SEC_RELOC) == 0
>>>>>         || sec->reloc_count == 0
>>>>> -      || elf_seg_map (info->output_bfd) == NULL
>>>>>         || (info->disable_target_specific_optimizations
>>>>>         && info->relax_pass == 0)
>>>>>         /* The exp_seg_relro_adjust is enum phase_enum (0x4),
>>>>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.dd 
>>>>> b/ld/testsuite/ld-loongarch-elf/relax.dd
>>>>> new file mode 100644
>>>>> index 000000000..e266beb8f
>>>>> --- /dev/null
>>>>> +++ b/ld/testsuite/ld-loongarch-elf/relax.dd
>>>>> @@ -0,0 +1,6 @@
>>>>> +#...
>>>>> +.*pcaddi.*
>>>>> +.*ld.w.*
>>>>> +.*pcaddi.*
>>>>> +.*ld.w.*
>>>>> +#pass
>>>>> diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp 
>>>>> b/ld/testsuite/ld-loongarch-elf/relax.exp
>>>>> index 7ff876d79..d2bb967c6 100644
>>>>> --- a/ld/testsuite/ld-loongarch-elf/relax.exp
>>>>> +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
>>>>> @@ -21,31 +21,6 @@
>>>>>     if [istarget loongarch64-*-*] {
>>>>>   -  if [isbuild loongarch64-*-*] {
>>>>> -    set testname "loongarch relax build"
>>>>> -    set pre_builds [list \
>>>>> -      [list \
>>>>> -    "$testname" \
>>>>> -    "" \
>>>>> -    "" \
>>>>> -    {relax.s} \
>>>>> -    {} \
>>>>> -    "relax" \
>>>>> -      ] \
>>>>> -    ]
>>>>> -
>>>>> -    run_cc_link_tests $pre_builds
>>>>> -
>>>>> -    if [file exist "tmpdir/relax"] {
>>>>> -      set objdump_output [run_host_cmd "objdump" "-d tmpdir/relax"]
>>>>> -      if { [ regexp ".*pcaddi.*pcaddi.*" $objdump_output] } {
>>>>> -    pass "loongarch relax"
>>>>> -      } {
>>>>> -    fail "loongarch relax"
>>>>> -      }
>>>>> -    }
>>>>> -  }
>>>>> -
>>>>>     run_ld_link_tests \
>>>>>         [list \
>>>>>         [list \
>>>>> @@ -58,6 +33,16 @@ if [istarget loongarch64-*-*] {
>>>>>             ] \
>>>>>             "relax-align" \
>>>>>         ] \
>>>>> +      [list \
>>>>> +          "relax" \
>>>>> +          "-e 0 -Ttext 0x10000 -Tdata 0x20000" "" \
>>>>> +          "" \
>>>>> +          {relax.s} \
>>>>> +          [list \
>>>>> +          [list objdump -d relax.dd] \
>>>>> +          ] \
>>>>> +          "relax" \
>>>>> +      ] \
>>>>>         ]
>>>>>       set objdump_flags "-s -j .data"

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[Xi Ruoyao]

Hi Jinyang,

Any progress on this?  During my attempt trying to balance relaxation
and scheduling better in GCC I found the elf_seg_map condition is
preventing relaxation on *every* shared library (when we are linking a
shared library the elf_seg_map of .text is NULL).

On a modern system most code paths are in shared libraries, so it's
really bad not to perform the relaxation on them.  Esp. now we are
disabling explicit relocs for relaxation, so if we don't relax shared
libraries we are likely regressing the overall performance of the
system.

Sorry for disturbing you during the national holiday, feel free to defer
the reply until the holiday ends!

On Thu, 2023-07-13 at 16:18 +0800, Jinyang He wrote:
> On 2023-07-13 15:19, Jinyang He wrote:
> 
> > Hi,
> > 
> > 
> > We should pay attention to them, the bug in relaxation. Relaxation may 
> > not work correctly because of the bug1 reported by the second patch 
> > and the bug2 reported in the my previous email, although it works well 
> > in most of the time. Those 2 bugs are just what we've found, but there 
> > may be hidden problems.
> > I also tested the bug2 on RISCV and although it couldn't be resolved, 
> > it reported an error.
> > 
> > Test is,
> > $ cat c.s
> >   .section ".another.text", "x"
> >   .fill 1, 4, 0
> >   call fn2
> >   call fn2
> > fn1:
> >   nop
> > 
> > .text
> > fn2:
> >   .fill 4, 4, 0
> >   call fn1
> > 
> > $ ./gas/as-new  -march=rv32ic_zicsr -mno-arch-attr  -o c.o c.s
> > $ ./ld/ld-new c.o -o c -e 0 --section-start=.another.text=0x1000000 
> > -Ttext 0x1100000
> > c.o: in function `fn2':
> > (.text+0x10): relocation truncated to fit: R_RISCV_JAL against `fn1'
> > 
> > So, I'll find the reason why reloc_bits_pcrel20_s2() not reports the
> > overfollow error, and add error report which I think it is more 
> > important than these two patches so that we can get feedback when we
> > link.
> > 
> 
> Now, I find that the sign-overflow-check has bug, include 
> reloc_bits_pcrel20_s2(), reloc_bits_b26() and (others, I did not test 
> them). And I think the "mask" should be
>      bfd_signed_vma mask = ((bfd_signed_vma)0x1 << (howto->bitsize - 
> (sign ? 1 : 0)) - 1;
> 
> The test about reloc_bits_b26() is,
> 
> $ cat d.s
>          .section ".another.text", "x"
>          b       sym1
> 
>          .text
>          nop
> sym1:
>          nop
> 
> $ ./gas/as-new -mabi=lp64d -o d.o d.s
> $ ./ld/ld-new d.o -o d -e 0 --section-start=.another.text=0x130000000 
> -Ttext 0x120000000
> 
> I'll do fix and send v2 after you test spec2006. Or other responses?
> 
> 
> Thanks!
> 
> 
> > 
> > On 2023-07-13 11:13, mengqinggang wrote:
> > > Hi,
> > > 
> > > I will apply this two patches to see if there are any errors in 
> > > specc2006.
> > > 
> > > 在 2023/7/12 下午4:08, Jinyang He 写道:
> > > > Hi,
> > > > 
> > > > 
> > > > I'm not fimiliar with the process of output binary. I just noted
> > > > that it calls lang_relax_sections() before calling 
> > > > _bfd_elf_map_sections_to_segments() in ldelf_map_segments(). Thus I 
> > > > think the condition, elf_seg_map (info->output_bfd) == NULL, always 
> > > > be true when first time it calls loongarch_elf_relax_section(). 
> > > > Actually we can get right symbol value when relaxation, but ...
> > > > 
> > > > You reminder me that the symbol value will be reduced due to 
> > > > relaxation, which like the instruction pc is reduced. Then we cannot 
> > > > get right symbol value if the symbol in relaxable section. And I
> > > > write a test,
> > > > 
> > > > $ cat c.s
> > > >     .section ".another.text", "x"
> > > >     nop
> > > >     la.local $a0, sym1
> > > > sym2:
> > > >     nop
> > > > 
> > > >     .text
> > > > sym1:
> > > >     nop
> > > >     nop
> > > >     nop
> > > >     la.local $a0, sym2
> > > > 
> > > > $ ./gas/as-new -mabi=lp64d -o c.o c.s
> > > > $ ./ld/ld-new c.o -o c -e 0 
> > > > --section-start=.another.text=0x120000000 -Ttext 0x120200000
> > > > 
> > > > Disassembly of section .another.text:
> > > > 
> > > > 0000000120000000 <sym2-0x8>:
> > > >    120000000:    03400000     andi            $zero, $zero, 0x0
> > > >    120000004:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
> > > > 
> > > > 0000000120000008 <sym2>:
> > > >    120000008:    03400000     andi            $zero, $zero, 0x0
> > > > 
> > > > Disassembly of section .text:
> > > > 
> > > > 0000000120200000 <sym1>:
> > > >    120200000:    03400000     andi            $zero, $zero, 0x0
> > > >    120200004:    03400000     andi            $zero, $zero, 0x0
> > > >    120200008:    03400000     andi            $zero, $zero, 0x0
> > > >    12020000c:    18ffffe4     pcaddi          $a0, 524287(0x7ffff)
> > > > 
> > > > Due to the bug repaired by Patch2 and the bug reported by this test. 
> > > > And I also did not see that condition in other archs. I'm not sure 
> > > > that the relaxation spec2006 error is caused by that condition or 
> > > > those bugs.
> > > > 
> > > > 
> > > > On 2023-07-12 14:35, mengqinggang wrote:
> > > > > Hi,
> > > > > 
> > > > > Without this condition, the value of 'symbol - pc' may be 
> > > > > differences between
> > > > > loongarch_elf_relax_section and loongarch_elf_relocate_section.
> > > > > And it will cause some spec2006 test errors.
> > > > > 
> > > > > 在 2023/7/11 下午4:49, Jinyang He 写道:
> > > > > > When I tried "./ld-new sth." the relax does not work because the
> > > > > > elf_seg_map (info->output_bfd) was NULL in 
> > > > > > loongarch_elf_relax_section.
> > > > > > There is no need for the segment info, we can get the address through
> > > > > > the section info. Thus, remove this condition.
> > > > > > 
> > > > > > bfd/ChangeLog:
> > > > > > 
> > > > > >     * elfnn-loongarch.c (loongarch_elf_relax_section): Remove
> > > > > >     elf_seg_map condition.
> > > > > > 
> > > > > > ld/ChangeLog:
> > > > > > 
> > > > > >     * testsuite/ld-loongarch-elf/relax.exp: Update trigger method.
> > > > > >     * testsuite/ld-loongarch-elf/relax.dd: New test.
> > > > > > ---
> > > > > >   bfd/elfnn-loongarch.c                   |  1 -
> > > > > >   ld/testsuite/ld-loongarch-elf/relax.dd  |  6 +++++
> > > > > >   ld/testsuite/ld-loongarch-elf/relax.exp | 35 
> > > > > > +++++++------------------
> > > > > >   3 files changed, 16 insertions(+), 26 deletions(-)
> > > > > >   create mode 100644 ld/testsuite/ld-loongarch-elf/relax.dd
> > > > > > 
> > > > > > diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
> > > > > > index d3d8419d8..01f349a24 100644
> > > > > > --- a/bfd/elfnn-loongarch.c
> > > > > > +++ b/bfd/elfnn-loongarch.c
> > > > > > @@ -3845,7 +3845,6 @@ loongarch_elf_relax_section (bfd *abfd, 
> > > > > > asection *sec,
> > > > > >         || sec->sec_flg0
> > > > > >         || (sec->flags & SEC_RELOC) == 0
> > > > > >         || sec->reloc_count == 0
> > > > > > -      || elf_seg_map (info->output_bfd) == NULL
> > > > > >         || (info->disable_target_specific_optimizations
> > > > > >         && info->relax_pass == 0)
> > > > > >         /* The exp_seg_relro_adjust is enum phase_enum (0x4),
> > > > > > diff --git a/ld/testsuite/ld-loongarch-elf/relax.dd 
> > > > > > b/ld/testsuite/ld-loongarch-elf/relax.dd
> > > > > > new file mode 100644
> > > > > > index 000000000..e266beb8f
> > > > > > --- /dev/null
> > > > > > +++ b/ld/testsuite/ld-loongarch-elf/relax.dd
> > > > > > @@ -0,0 +1,6 @@
> > > > > > +#...
> > > > > > +.*pcaddi.*
> > > > > > +.*ld.w.*
> > > > > > +.*pcaddi.*
> > > > > > +.*ld.w.*
> > > > > > +#pass
> > > > > > diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp 
> > > > > > b/ld/testsuite/ld-loongarch-elf/relax.exp
> > > > > > index 7ff876d79..d2bb967c6 100644
> > > > > > --- a/ld/testsuite/ld-loongarch-elf/relax.exp
> > > > > > +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
> > > > > > @@ -21,31 +21,6 @@
> > > > > >     if [istarget loongarch64-*-*] {
> > > > > >   -  if [isbuild loongarch64-*-*] {
> > > > > > -    set testname "loongarch relax build"
> > > > > > -    set pre_builds [list \
> > > > > > -      [list \
> > > > > > -    "$testname" \
> > > > > > -    "" \
> > > > > > -    "" \
> > > > > > -    {relax.s} \
> > > > > > -    {} \
> > > > > > -    "relax" \
> > > > > > -      ] \
> > > > > > -    ]
> > > > > > -
> > > > > > -    run_cc_link_tests $pre_builds
> > > > > > -
> > > > > > -    if [file exist "tmpdir/relax"] {
> > > > > > -      set objdump_output [run_host_cmd "objdump" "-d tmpdir/relax"]
> > > > > > -      if { [ regexp ".*pcaddi.*pcaddi.*" $objdump_output] } {
> > > > > > -    pass "loongarch relax"
> > > > > > -      } {
> > > > > > -    fail "loongarch relax"
> > > > > > -      }
> > > > > > -    }
> > > > > > -  }
> > > > > > -
> > > > > >     run_ld_link_tests \
> > > > > >         [list \
> > > > > >         [list \
> > > > > > @@ -58,6 +33,16 @@ if [istarget loongarch64-*-*] {
> > > > > >             ] \
> > > > > >             "relax-align" \
> > > > > >         ] \
> > > > > > +      [list \
> > > > > > +          "relax" \
> > > > > > +          "-e 0 -Ttext 0x10000 -Tdata 0x20000" "" \
> > > > > > +          "" \
> > > > > > +          {relax.s} \
> > > > > > +          [list \
> > > > > > +          [list objdump -d relax.dd] \
> > > > > > +          ] \
> > > > > > +          "relax" \
> > > > > > +      ] \
> > > > > >         ]
> > > > > >       set objdump_flags "-s -j .data"
> 

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[Xi Ruoyao]

On Thu, 2023-10-05 at 18:09 +0800, Xi Ruoyao via Binutils wrote:
> Hi Jinyang,
> 
> Any progress on this?  During my attempt trying to balance relaxation
> and scheduling better in GCC I found the elf_seg_map condition is
> preventing relaxation on *every* shared library (when we are linking a
> shared library the elf_seg_map of .text is NULL).
> 
> On a modern system most code paths are in shared libraries, so it's
> really bad not to perform the relaxation on them.  Esp. now we are
> disabling explicit relocs for relaxation, so if we don't relax shared
> libraries we are likely regressing the overall performance of the
> system.

Phew.  It's not only a performance issue.  It's actually a *correctness*
issue because the condition also causes R_LARCH_ALIGN skipped, so some
programs depending on code alignment (for e.g. duff-device-like code
using pcaddi for eg) will be broken.

Generally skipping the entire relaxation pass for any section containing
R_LARCH_ALIGN is wrong (as we've discussed in
https://github.com/llvm/llvm-project/pull/67424).  Even if we don't
really relax a thing we still *must* process R_LARCH_ALIGN.

> Sorry for disturbing you during the national holiday, feel free to defer
> the reply until the holiday ends!

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[mengqinggang]

Hi,

I will send a patch in the next few days to solve this issue and other 
issues
related to relaxation.


在 2023/10/5 下午7:19, Xi Ruoyao 写道:
> On Thu, 2023-10-05 at 18:09 +0800, Xi Ruoyao via Binutils wrote:
>> Hi Jinyang,
>>
>> Any progress on this?  During my attempt trying to balance relaxation
>> and scheduling better in GCC I found the elf_seg_map condition is
>> preventing relaxation on *every* shared library (when we are linking a
>> shared library the elf_seg_map of .text is NULL).
>>
>> On a modern system most code paths are in shared libraries, so it's
>> really bad not to perform the relaxation on them.  Esp. now we are
>> disabling explicit relocs for relaxation, so if we don't relax shared
>> libraries we are likely regressing the overall performance of the
>> system.
> Phew.  It's not only a performance issue.  It's actually a *correctness*
> issue because the condition also causes R_LARCH_ALIGN skipped, so some
> programs depending on code alignment (for e.g. duff-device-like code
> using pcaddi for eg) will be broken.
>
> Generally skipping the entire relaxation pass for any section containing
> R_LARCH_ALIGN is wrong (as we've discussed in
> https://github.com/llvm/llvm-project/pull/67424).  Even if we don't
> really relax a thing we still *must* process R_LARCH_ALIGN.
>
>> Sorry for disturbing you during the national holiday, feel free to defer
>> the reply until the holiday ends!

Re: [PATCH 1/2] LoongArch: bfd: Remove elf_seg_map condition in loongarch_elf_relax_section

[Xi Ruoyao]

On Sat, 2023-10-07 at 09:23 +0800, mengqinggang wrote:
> 
> Hi,
> 
> I will send a patch in the next few days to solve this issue and other
> issues
> related to relaxation.

You can refer to a related bug report,
https://sourceware.org/bugzilla/show_bug.cgi?id=30944, in the commit
message.

Thanks!

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University