From: H.J. Lu <hjl.tools@gmail.com>
Date: Sun, 11 Jan 2026 03:43:40 +0000 (+0800)
Subject: elf: Handle the section flag 'o' linked to special sections
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2b17961bfb8b2b0d9701c9c0796a5f5749337fc7;p=thirdparty%2Fbinutils-gdb.git

elf: Handle the section flag 'o' linked to special sections

Call _bfd_elf_section_from_bfd_section to get the sh_link value from
the section flag 'o' directive, which may point to special sections,
like SHN_ABS or SHN_COMM.  Update readelf to print the special section
names in the sh_link field and replace "internal->sh_link > num" with
"internal->sh_link >= num".

bfd/

	PR gas/33744
	* elf.c (assign_section_numbers): Call
	_bfd_elf_section_from_bfd_section to get the sh_link value.

binutils/

	PR gas/33744
	* readelf.c (special_defined_section_index): New.
	(get_32bit_section_headers): Don't warn special section indexes
	in the sh_link field.
	(get_64bit_section_headers): Likewise.
	(process_section_headers): Print special defined section names.

gas/

	PR gas/33744
	* testsuite/gas/elf/elf.exp: Run PR gas/33744 tests.
	* testsuite/gas/elf/sh-link-abs-1.d: New file.
	* testsuite/gas/elf/sh-link-abs-2.d: Likewise.
	* testsuite/gas/elf/sh-link-abs-3-32.d: Likewise.
	* testsuite/gas/elf/sh-link-abs-3-64.d: Likewise.
	* testsuite/gas/elf/sh-link-abs-4-32.d: Likewise.
	* testsuite/gas/elf/sh-link-abs-4-64.d: Likewise.
	* testsuite/gas/elf/sh-link-abs.s: Likewise.
	* testsuite/gas/elf/sh-link-common-1.d: Likewise.
	* testsuite/gas/elf/sh-link-common-2.d: Likewise.
	* testsuite/gas/elf/sh-link-common-3-32.d: Likewise.
	* testsuite/gas/elf/sh-link-common-3-64.d: Likewise.
	* testsuite/gas/elf/sh-link-common-4-32.d: Likewise.
	* testsuite/gas/elf/sh-link-common-4-64.d: Likewise.
	* testsuite/gas/elf/sh-link-common.s: Likewise.
	* testsuite/gas/elf/sh-link-large-common-1.d: Likewise.
	* testsuite/gas/elf/sh-link-large-common-2.d: Likewise.
	* testsuite/gas/elf/sh-link-large-common-3.d: Likewise.
	* testsuite/gas/elf/sh-link-large-common-4.d: Likewise.
	* testsuite/gas/elf/sh-link-large-common.s: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
---

diff --git a/bfd/elf.c b/bfd/elf.c
index 8b6dd3ce370..1177c3c3016 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -4333,7 +4333,8 @@ assign_section_numbers (bfd *abfd, struct bfd_link_info *link_info)
 		  return false;
 		}
 	      s = s->output_section;
-	      d->this_hdr.sh_link = elf_section_data (s)->this_idx;
+	      d->this_hdr.sh_link
+		= _bfd_elf_section_from_bfd_section (abfd, s);
 	    }
 	}
 
diff --git a/binutils/readelf.c b/binutils/readelf.c
index d26e2bfa7b9..5b7fc0dc1de 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -1010,6 +1010,50 @@ is_ia64_vms (Filedata * filedata)
     && filedata->file_header.e_ident[EI_OSABI] == ELFOSABI_OPENVMS;
 }
 
+/* Return true if NDX is a special defined section index.  */
+
+static bool
+special_defined_section_index (Filedata *filedata, size_t ndx)
+{
+  if (ndx == SHN_ABS || ndx == SHN_COMMON)
+    return true;
+
+  if (filedata != NULL)
+    switch (filedata->file_header.e_machine)
+      {
+      case EM_MIPS:
+	if (ndx == SHN_MIPS_SCOMMON)
+	  return true;
+	break;
+
+      case EM_TI_C6000:
+	if (ndx == SHN_TIC6X_SCOMMON)
+	  return true;
+	break;
+
+      case EM_X86_64:
+      case EM_L1OM:
+      case EM_K1OM:
+	if (ndx == SHN_X86_64_LCOMMON)
+	  return true;
+	break;
+
+      case EM_IA_64:
+	if (filedata->file_header.e_ident[EI_OSABI] == ELFOSABI_HPUX
+	    && ndx == SHN_IA_64_ANSI_COMMON)
+	  return true;
+
+	if (is_ia64_vms (filedata) && ndx == SHN_IA_64_VMS_SYMVEC)
+	  return true;
+	break;
+
+      default:
+	break;
+      }
+
+  return false;
+}
+
 static const char *
 printable_section_name_from_index (Filedata *  filedata,
 				   size_t      ndx,
@@ -7833,7 +7877,10 @@ get_32bit_section_headers (Filedata * filedata, bool probe)
       internal->sh_info      = BYTE_GET (shdrs[i].sh_info);
       internal->sh_addralign = BYTE_GET (shdrs[i].sh_addralign);
       internal->sh_entsize   = BYTE_GET (shdrs[i].sh_entsize);
-      if (!probe && internal->sh_link > num)
+      if (!probe
+	  && internal->sh_link >= num
+	  && !special_defined_section_index (filedata,
+					     internal->sh_link))
 	warn (_("Section %u has an out of range sh_link value of %u\n"), i, internal->sh_link);
       if (!probe && internal->sh_flags & SHF_INFO_LINK && internal->sh_info > num)
 	warn (_("Section %u has an out of range sh_info value of %u\n"), i, internal->sh_info);
@@ -7905,7 +7952,10 @@ get_64bit_section_headers (Filedata * filedata, bool probe)
       internal->sh_info      = BYTE_GET (shdrs[i].sh_info);
       internal->sh_offset    = BYTE_GET (shdrs[i].sh_offset);
       internal->sh_addralign = BYTE_GET (shdrs[i].sh_addralign);
-      if (!probe && internal->sh_link > num)
+      if (!probe
+	  && internal->sh_link >= num
+	  && !special_defined_section_index (filedata,
+					     internal->sh_link))
 	warn (_("Section %u has an out of range sh_link value of %u\n"), i, internal->sh_link);
       if (!probe && internal->sh_flags & SHF_INFO_LINK && internal->sh_info > num)
 	warn (_("Section %u has an out of range sh_info value of %u\n"), i, internal->sh_info);
@@ -9004,6 +9054,9 @@ process_section_headers (Filedata * filedata)
       printf (do_wide ? " %-15s " : " %-15.15s ",
 	      get_section_type_name (filedata, section->sh_type));
 
+      bool special_defined_section
+	= special_defined_section_index (filedata, section->sh_link);
+
       if (is_32bit_elf)
 	{
 	  const char * link_too_big = NULL;
@@ -9020,7 +9073,8 @@ process_section_headers (Filedata * filedata)
 	  else
 	    printf (" %3s ", get_elf_section_flags (filedata, section->sh_flags));
 
-	  if (section->sh_link >= filedata->file_header.e_shnum)
+	  if (!special_defined_section
+	      && section->sh_link >= filedata->file_header.e_shnum)
 	    {
 	      link_too_big = "";
 	      /* The sh_link value is out of range.  Normally this indicates
@@ -9046,20 +9100,27 @@ process_section_headers (Filedata * filedata)
 		}
 	    }
 
+	  if (special_defined_section)
+	    printf ("%2s ",
+		    printable_section_name_from_index (filedata,
+						       section->sh_link,
+						       NULL));
+
 	  if (do_section_details)
 	    {
-	      if (link_too_big != NULL && * link_too_big)
-		printf ("<%s> ", link_too_big);
-	      else
-		printf ("%2u ", section->sh_link);
-	      printf ("%3u %2lu\n", section->sh_info,
-		      (unsigned long) section->sh_addralign);
+	      if (!special_defined_section)
+		{
+		  if (link_too_big != NULL && * link_too_big)
+		    printf ("<%s> ", link_too_big);
+		  else
+		    printf ("%2u ", section->sh_link);
+		}
 	    }
-	  else
-	    printf ("%2u %3u %2lu\n",
-		    section->sh_link,
-		    section->sh_info,
-		    (unsigned long) section->sh_addralign);
+	  else if (!special_defined_section)
+	    printf ("%2u ", section->sh_link);
+
+	  printf ("%3u %2lu\n", section->sh_info,
+		  (unsigned long) section->sh_addralign);
 
 	  if (link_too_big && ! * link_too_big)
 	    warn (_("section %u: sh_link value of %u is larger than the number of sections\n"),
@@ -9096,9 +9157,17 @@ process_section_headers (Filedata * filedata)
 	  if (do_section_details)
 	    fputs ("  ", stdout);
 	  else
-	    printf (" %3s ", get_elf_section_flags (filedata, section->sh_flags));
-
-	  printf ("%2u %3u ", section->sh_link, section->sh_info);
+	    printf (" %3s ", get_elf_section_flags (filedata,
+						    section->sh_flags));
+
+	  if (special_defined_section)
+	    printf ("%2s ",
+		    printable_section_name_from_index (filedata,
+						       section->sh_link,
+						       NULL));
+	  else
+	    printf ("%2u ", section->sh_link);
+	  printf ("%3u ", section->sh_info);
 
 	  if ((unsigned long) section->sh_addralign == section->sh_addralign)
 	    printf ("%2lu\n", (unsigned long) section->sh_addralign);
@@ -9119,7 +9188,13 @@ process_section_headers (Filedata * filedata)
 	      printf ("  ");
 	      print_vma (section->sh_offset, LONG_HEX);
 	    }
-	  printf ("  %u\n       ", section->sh_link);
+	  if (special_defined_section)
+	    printf ("  %s\n       ",
+		    printable_section_name_from_index (filedata,
+						       section->sh_link,
+						       NULL));
+	  else
+	    printf ("  %u\n       ", section->sh_link);
 	  print_vma (section->sh_size, LONG_HEX);
 	  putchar (' ');
 	  print_vma (section->sh_entsize, LONG_HEX);
@@ -9146,8 +9221,15 @@ process_section_headers (Filedata * filedata)
 
 	  printf (" %3s ", get_elf_section_flags (filedata, section->sh_flags));
 
-	  printf ("     %2u   %3u     %lu\n",
-		  section->sh_link,
+	  if (special_defined_section)
+	    printf ("     %2s",
+		    printable_section_name_from_index (filedata,
+						       section->sh_link,
+						       NULL));
+	  else
+	    printf ("     %2u",
+		    section->sh_link);
+	  printf ("   %3u     %lu\n",
 		  section->sh_info,
 		  (unsigned long) section->sh_addralign);
 	}
diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
index 35e06ce58b3..b4b4272ab9f 100644
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@@ -290,6 +290,25 @@ if { [is_elf_format] } then {
     run_dump_test "section28"
     run_dump_test "section29"
     run_dump_test "section30" $dump_opts
+    run_dump_test "sh-link-abs-1"
+    run_dump_test "sh-link-abs-2"
+    run_dump_test "sh-link-common-1"
+    run_dump_test "sh-link-common-2"
+    if [is_elf64 tmpdir/section30.o] {
+	run_dump_test "sh-link-abs-3-64"
+	run_dump_test "sh-link-abs-4-64"
+	run_dump_test "sh-link-common-3-64"
+	run_dump_test "sh-link-common-4-64"
+	run_dump_test "sh-link-large-common-1"
+	run_dump_test "sh-link-large-common-2"
+	run_dump_test "sh-link-large-common-3"
+	run_dump_test "sh-link-large-common-4"
+    } else {
+	run_dump_test "sh-link-abs-3-32"
+	run_dump_test "sh-link-abs-4-32"
+	run_dump_test "sh-link-common-3-32"
+	run_dump_test "sh-link-common-4-32"
+    }
     run_dump_test "sh-link-zero"
     run_dump_test "string"
     run_dump_test "size"
diff --git a/gas/testsuite/gas/elf/sh-link-abs-1.d b/gas/testsuite/gas/elf/sh-link-abs-1.d
new file mode 100644
index 00000000000..7010df0425f
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-abs-1.d
@@ -0,0 +1,6 @@
+#source: sh-link-abs.s
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +WAL +ABS +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-abs-2.d b/gas/testsuite/gas/elf/sh-link-abs-2.d
new file mode 100644
index 00000000000..e3058a97288
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-abs-2.d
@@ -0,0 +1,8 @@
+#source: sh-link-abs.s
+#readelf: -tW
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +ABS +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-abs-3-32.d b/gas/testsuite/gas/elf/sh-link-abs-3-32.d
new file mode 100644
index 00000000000..efac2f115fc
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-abs-3-32.d
@@ -0,0 +1,6 @@
+#source: sh-link-abs.s
+#readelf: -S
+
+#...
+ +\[ *[0-9]+\] +__patchable_\[\.\.\.\] +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +WAL +ABS +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-abs-3-64.d b/gas/testsuite/gas/elf/sh-link-abs-3-64.d
new file mode 100644
index 00000000000..5724d27b2c9
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-abs-3-64.d
@@ -0,0 +1,7 @@
+#source: sh-link-abs.s
+#readelf: -S
+
+#...
+ +\[ *[0-9]+\] +__patchable_\[\.\.\.\] +PROGBITS +[0-9a-f]+ +[0-9a-f]+
+ +0+[248] +0+ +WAL +ABS +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-abs-4-32.d b/gas/testsuite/gas/elf/sh-link-abs-4-32.d
new file mode 100644
index 00000000000..31387c4b7f2
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-abs-4-32.d
@@ -0,0 +1,8 @@
+#source: sh-link-abs.s
+#readelf: -t
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +ABS +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-abs-4-64.d b/gas/testsuite/gas/elf/sh-link-abs-4-64.d
new file mode 100644
index 00000000000..d0ae74d01d5
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-abs-4-64.d
@@ -0,0 +1,9 @@
+#source: sh-link-abs.s
+#readelf: -t
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +ABS
+ +0+[248] +0+ +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-abs.s b/gas/testsuite/gas/elf/sh-link-abs.s
new file mode 100644
index 00000000000..7094c770299
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-abs.s
@@ -0,0 +1,6 @@
+	.section __patchable_function_entries,"awo",%progbits,foo
+	.dc.a	.LPFE1
+	.text
+.LPFE1:
+	.byte 0
+	.set	foo,0x1000
diff --git a/gas/testsuite/gas/elf/sh-link-common-1.d b/gas/testsuite/gas/elf/sh-link-common-1.d
new file mode 100644
index 00000000000..1e042efbc17
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-common-1.d
@@ -0,0 +1,6 @@
+#source: sh-link-common.s
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +WAL +COM +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-common-2.d b/gas/testsuite/gas/elf/sh-link-common-2.d
new file mode 100644
index 00000000000..aaed278bccf
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-common-2.d
@@ -0,0 +1,8 @@
+#source: sh-link-common.s
+#readelf: -tW
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +COM +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-common-3-32.d b/gas/testsuite/gas/elf/sh-link-common-3-32.d
new file mode 100644
index 00000000000..e2ca20f447f
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-common-3-32.d
@@ -0,0 +1,6 @@
+#source: sh-link-common.s
+#readelf: -S
+
+#...
+ +\[ *[0-9]+\] +__patchable_\[\.\.\.\] +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +WAL +COM +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-common-3-64.d b/gas/testsuite/gas/elf/sh-link-common-3-64.d
new file mode 100644
index 00000000000..86a2b9f7f39
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-common-3-64.d
@@ -0,0 +1,7 @@
+#source: sh-link-common.s
+#readelf: -S
+
+#...
+ +\[ *[0-9]+\] +__patchable_\[\.\.\.\] +PROGBITS +[0-9a-f]+ +[0-9a-f]+
+ +0+[248] +0+ +WAL +COM +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-common-4-32.d b/gas/testsuite/gas/elf/sh-link-common-4-32.d
new file mode 100644
index 00000000000..ad0bb1b8193
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-common-4-32.d
@@ -0,0 +1,8 @@
+#source: sh-link-common.s
+#readelf: -t
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +COM +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-common-4-64.d b/gas/testsuite/gas/elf/sh-link-common-4-64.d
new file mode 100644
index 00000000000..4637b72883b
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-common-4-64.d
@@ -0,0 +1,9 @@
+#source: sh-link-common.s
+#readelf: -t
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +COM
+ +0+[248] +0+ +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-common.s b/gas/testsuite/gas/elf/sh-link-common.s
new file mode 100644
index 00000000000..84ec3e446df
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-common.s
@@ -0,0 +1,6 @@
+	.section __patchable_function_entries,"awo",%progbits,foo
+	.dc.a	.LPFE1
+	.text
+.LPFE1:
+	.byte 0
+        .comm   foo,8
diff --git a/gas/testsuite/gas/elf/sh-link-large-common-1.d b/gas/testsuite/gas/elf/sh-link-large-common-1.d
new file mode 100644
index 00000000000..acf238c8d1c
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-large-common-1.d
@@ -0,0 +1,8 @@
+#source: sh-link-large-common.s
+#readelf: -S
+#target: x86_64-*-*
+
+#...
+ +\[ *[0-9]+\] +__patchable_\[\.\.\.\] +PROGBITS +[0-9a-f]+ +[0-9a-f]+
+ +0+[248] +0+ +WAL +LARGE_COM +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-large-common-2.d b/gas/testsuite/gas/elf/sh-link-large-common-2.d
new file mode 100644
index 00000000000..36d983761b7
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-large-common-2.d
@@ -0,0 +1,7 @@
+#source: sh-link-large-common.s
+#readelf: -SW
+#target: x86_64-*-*
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +WAL +LARGE_COM +0 +1
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-large-common-3.d b/gas/testsuite/gas/elf/sh-link-large-common-3.d
new file mode 100644
index 00000000000..d738a90482e
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-large-common-3.d
@@ -0,0 +1,10 @@
+#source: sh-link-large-common.s
+#readelf: -t
+#target: x86_64-*-*
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +LARGE_COM
+ +0+[248] +0+ +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-large-common-4.d b/gas/testsuite/gas/elf/sh-link-large-common-4.d
new file mode 100644
index 00000000000..0101e54da7a
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-large-common-4.d
@@ -0,0 +1,9 @@
+#source: sh-link-large-common.s
+#readelf: -tW
+#target: x86_64-*-*
+
+#...
+ +\[ *[0-9]+\] +__patchable_function_entries
+ +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+[248] +0+ +LARGE_COM +0 +1
+ +\[0+83\]: WRITE, ALLOC, LINK ORDER
+#pass
diff --git a/gas/testsuite/gas/elf/sh-link-large-common.s b/gas/testsuite/gas/elf/sh-link-large-common.s
new file mode 100644
index 00000000000..b2ef554dbc9
--- /dev/null
+++ b/gas/testsuite/gas/elf/sh-link-large-common.s
@@ -0,0 +1,6 @@
+	.section __patchable_function_entries,"awo",%progbits,foo
+	.dc.a	.LPFE1
+	.text
+.LPFE1:
+	.byte 0
+	.largecomm foo,30,8