[PATCH] elf: Allow mixed ordered/unordered inputs for non-relocatable link

H.J. Lu hjl.tools@gmail.com
Mon Dec 21 21:54:28 GMT 2020


For non-relocatable link with SHF_LINK_ORDER inputs, allow mixed indirect
and data inputs with ordered and unordered inputs:

1. Add pattern to bfd_section for the matching section name pattern in
linker script and update BFD_FAKE_SECTION.
2. Sort the consecutive bfd_indirect_link_order sections with the same
pattern to allow linker script to overdide input section order.
3. Place unordered sections before ordered sections.
4. Change the offsets of the indirect input sections only.

bfd/

	PR ld/26256
	* elflink.c (compare_link_order): Place unordered sections before
	ordered sections.
	(elf_fixup_link_order): Add a link info argument.  Allow mixed
	ordered and unordered input sections for non-relocatable link.
	Sort the consecutive bfd_indirect_link_order sections with the
	same pattern.  Change the offsets of the bfd_indirect_link_order
	sections only.
	(bfd_elf_final_link): Pass info to elf_fixup_link_order.
	* section.c (bfd_section): Add pattern.
	(BFD_FAKE_SECTION): Initialize pattern to NULL.
	* bfd-in2.h: Regenerated.

gas/

	PR ld/26256
	* config/obj-elf.c (obj_elf_change_section): Also filter out
	SHF_LINK_ORDER.

ld/

	PR ld/26256
	* ldlang.c (gc_section_callback): Set pattern.
	* testsuite/ld-elf/pr26256-1.s: New file.
	* testsuite/ld-elf/pr26256-1.t: Likewise.
	* testsuite/ld-elf/pr26256-1a.d: Likewise.
	* testsuite/ld-elf/pr26256-1b.d: Likewise.
	* testsuite/ld-elf/pr26256-2.s: Likewise.
	* testsuite/ld-elf/pr26256-2.t: Likewise.
	* testsuite/ld-elf/pr26256-2a.d: Likewise.
	* testsuite/ld-elf/pr26256-2b.d: Likewise.
	* testsuite/ld-elf/pr26256-3.s: Likewise.
	* testsuite/ld-elf/pr26256-3a.d: Likewise.
	* testsuite/ld-elf/pr26256-3a.t: Likewise.
	* testsuite/ld-elf/pr26256-3b.d: Likewise.
	* testsuite/ld-elf/pr26256-3b.t: Likewise.
---
 bfd/bfd-in2.h                    |  7 ++-
 bfd/elflink.c                    | 83 ++++++++++++++++++++++++--------
 bfd/section.c                    |  7 ++-
 gas/config/obj-elf.c             |  4 +-
 ld/ldlang.c                      |  4 +-
 ld/testsuite/ld-elf/pr26256-1.s  | 20 ++++++++
 ld/testsuite/ld-elf/pr26256-1.t  |  9 ++++
 ld/testsuite/ld-elf/pr26256-1a.d |  7 +++
 ld/testsuite/ld-elf/pr26256-1b.d |  7 +++
 ld/testsuite/ld-elf/pr26256-2.s  | 32 ++++++++++++
 ld/testsuite/ld-elf/pr26256-2.t  |  5 ++
 ld/testsuite/ld-elf/pr26256-2a.d | 19 ++++++++
 ld/testsuite/ld-elf/pr26256-2b.d | 19 ++++++++
 ld/testsuite/ld-elf/pr26256-3.s  | 18 +++++++
 ld/testsuite/ld-elf/pr26256-3a.d |  9 ++++
 ld/testsuite/ld-elf/pr26256-3a.t | 13 +++++
 ld/testsuite/ld-elf/pr26256-3b.d |  9 ++++
 ld/testsuite/ld-elf/pr26256-3b.t | 12 +++++
 18 files changed, 259 insertions(+), 25 deletions(-)
 create mode 100644 ld/testsuite/ld-elf/pr26256-1.s
 create mode 100644 ld/testsuite/ld-elf/pr26256-1.t
 create mode 100644 ld/testsuite/ld-elf/pr26256-1a.d
 create mode 100644 ld/testsuite/ld-elf/pr26256-1b.d
 create mode 100644 ld/testsuite/ld-elf/pr26256-2.s
 create mode 100644 ld/testsuite/ld-elf/pr26256-2.t
 create mode 100644 ld/testsuite/ld-elf/pr26256-2a.d
 create mode 100644 ld/testsuite/ld-elf/pr26256-2b.d
 create mode 100644 ld/testsuite/ld-elf/pr26256-3.s
 create mode 100644 ld/testsuite/ld-elf/pr26256-3a.d
 create mode 100644 ld/testsuite/ld-elf/pr26256-3a.t
 create mode 100644 ld/testsuite/ld-elf/pr26256-3b.d
 create mode 100644 ld/testsuite/ld-elf/pr26256-3b.t

diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index f1bef5742a..cc5a3c9912 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -1184,6 +1184,9 @@ typedef struct bfd_section
   struct bfd_symbol *symbol;
   struct bfd_symbol **symbol_ptr_ptr;
 
+  /* The matching section name pattern in linker script.  */
+  const char *pattern;
+
   /* Early in the link process, map_head and map_tail are used to build
      a list of input sections attached to an output section.  Later,
      output sections use these fields for a list of bfd_link_order
@@ -1377,8 +1380,8 @@ discarded_section (const asection *sec)
   /* target_index, used_by_bfd, constructor_chain, owner,           */ \
      0,            NULL,        NULL,              NULL,               \
                                                                        \
-  /* symbol,                    symbol_ptr_ptr,                     */ \
-     (struct bfd_symbol *) SYM, &SEC.symbol,                           \
+  /* symbol,                    symbol_ptr_ptr, pattern,            */ \
+     (struct bfd_symbol *) SYM, &SEC.symbol,    NULL,                  \
                                                                        \
   /* map_head, map_tail, already_assigned                           */ \
      { NULL }, { NULL }, NULL                                          \
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 1b3398126f..6930c7c741 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -11867,8 +11867,21 @@ compare_link_order (const void *a, const void *b)
   const struct bfd_link_order *blo = *(const struct bfd_link_order **) b;
   asection *asec = elf_linked_to_section (alo->u.indirect.section);
   asection *bsec = elf_linked_to_section (blo->u.indirect.section);
-  bfd_vma apos = asec->output_section->lma + asec->output_offset;
-  bfd_vma bpos = bsec->output_section->lma + bsec->output_offset;
+  bfd_vma apos, bpos;
+
+  /* Check if any sections are unordered.  */
+  if (asec == NULL || bsec == NULL)
+    {
+      /* Place unordered sections before ordered sections.  */
+      if (bsec != NULL)
+	return -1;
+      else if (asec != NULL)
+	return 1;
+      return 0;
+    }
+
+  apos = asec->output_section->lma + asec->output_offset;
+  bpos = bsec->output_section->lma + bsec->output_offset;
 
   if (apos < bpos)
     return -1;
@@ -11903,14 +11916,14 @@ compare_link_order (const void *a, const void *b)
    sections.  Ideally we'd do this in the linker proper.  */
 
 static bfd_boolean
-elf_fixup_link_order (bfd *abfd, asection *o)
+elf_fixup_link_order (struct bfd_link_info *info, bfd *abfd, asection *o)
 {
   size_t seen_linkorder;
   size_t seen_other;
   size_t n;
   struct bfd_link_order *p;
   bfd *sub;
-  struct bfd_link_order **sections;
+  struct bfd_link_order **sections, **indirect_sections;
   asection *other_sec, *linkorder_sec;
   bfd_vma offset;  /* Octets.  */
 
@@ -11941,7 +11954,9 @@ elf_fixup_link_order (bfd *abfd, asection *o)
       else
 	seen_other++;
 
-      if (seen_other && seen_linkorder)
+      /* Allow mixed ordered and unordered input sections for
+         non-relocatable link.  */
+      if (bfd_link_relocatable (info) && seen_other && seen_linkorder)
 	{
 	  if (other_sec && linkorder_sec)
 	    _bfd_error_handler
@@ -11961,6 +11976,10 @@ elf_fixup_link_order (bfd *abfd, asection *o)
   if (!seen_linkorder)
     return TRUE;
 
+  /* Non-relocatable output can have both ordered and unordered input
+     sections.  */
+  seen_linkorder += seen_other;
+
   sections = bfd_malloc (seen_linkorder * sizeof (*sections));
   if (sections == NULL)
     return FALSE;
@@ -11969,22 +11988,48 @@ elf_fixup_link_order (bfd *abfd, asection *o)
   for (p = o->map_head.link_order; p != NULL; p = p->next)
     sections[seen_linkorder++] = p;
 
-  /* Sort the input sections in the order of their linked section.  */
-  qsort (sections, seen_linkorder, sizeof (*sections), compare_link_order);
+  for (indirect_sections = sections, n = 0;
+       n < seen_linkorder;
+       indirect_sections++, n++)
+    {
+      /* Find the first bfd_indirect_link_order section.  */
+      if (indirect_sections[0]->type == bfd_indirect_link_order)
+	{
+	  /* Count the consecutive bfd_indirect_link_order sections
+	     with the same pattern.  */
+	  size_t i, n_indirect;
+	  const char *pattern
+	    = indirect_sections[0]->u.indirect.section->pattern;
+	  for (i = n + 1; i < seen_linkorder; i++)
+	    if (sections[i]->type != bfd_indirect_link_order
+		|| sections[i]->u.indirect.section->pattern != pattern)
+	      break;
+	  n_indirect = i - n;
+	  /* Sort the bfd_indirect_link_order sections in the order of
+	     their linked section.  */
+	  qsort (indirect_sections, n_indirect, sizeof (*sections),
+		 compare_link_order);
+	  indirect_sections += n_indirect;
+	  n += n_indirect;
+	}
+    }
 
-  /* Change the offsets of the sections.  */
+  /* Change the offsets of the bfd_indirect_link_order sections.  */
   offset = 0;
   for (n = 0; n < seen_linkorder; n++)
-    {
-      bfd_vma mask;
-      asection *s = sections[n]->u.indirect.section;
-      unsigned int opb = bfd_octets_per_byte (abfd, s);
-
-      mask = ~(bfd_vma) 0 << s->alignment_power * opb;
-      offset = (offset + ~mask) & mask;
-      sections[n]->offset = s->output_offset = offset / opb;
-      offset += sections[n]->size;
-    }
+    if (sections[n]->type == bfd_indirect_link_order)
+      {
+	bfd_vma mask;
+	asection *s = sections[n]->u.indirect.section;
+	unsigned int opb = bfd_octets_per_byte (abfd, s);
+
+	mask = ~(bfd_vma) 0 << s->alignment_power * opb;
+	offset = (offset + ~mask) & mask;
+	sections[n]->offset = s->output_offset = offset / opb;
+	offset += sections[n]->size;
+      }
+    else
+      offset = sections[n]->offset + sections[n]->size;
 
   free (sections);
   return TRUE;
@@ -12627,7 +12672,7 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
   /* Reorder SHF_LINK_ORDER sections.  */
   for (o = abfd->sections; o != NULL; o = o->next)
     {
-      if (!elf_fixup_link_order (abfd, o))
+      if (!elf_fixup_link_order (info, abfd, o))
 	return FALSE;
     }
 
diff --git a/bfd/section.c b/bfd/section.c
index 17f5b4c3d8..aa383626e2 100644
--- a/bfd/section.c
+++ b/bfd/section.c
@@ -541,6 +541,9 @@ CODE_FRAGMENT
 .  struct bfd_symbol *symbol;
 .  struct bfd_symbol **symbol_ptr_ptr;
 .
+.  {* The matching section name pattern in linker script.  *}
+.  const char *pattern;
+.
 .  {* Early in the link process, map_head and map_tail are used to build
 .     a list of input sections attached to an output section.  Later,
 .     output sections use these fields for a list of bfd_link_order
@@ -734,8 +737,8 @@ CODE_FRAGMENT
 .  {* target_index, used_by_bfd, constructor_chain, owner,           *}	\
 .     0,            NULL,        NULL,              NULL,		\
 .									\
-.  {* symbol,                    symbol_ptr_ptr,                     *}	\
-.     (struct bfd_symbol *) SYM, &SEC.symbol,				\
+.  {* symbol,                    symbol_ptr_ptr, pattern,            *}	\
+.     (struct bfd_symbol *) SYM, &SEC.symbol,    NULL,			\
 .									\
 .  {* map_head, map_tail, already_assigned                           *}	\
 .     { NULL }, { NULL }, NULL						\
diff --git a/gas/config/obj-elf.c b/gas/config/obj-elf.c
index d030b548fb..621c35c182 100644
--- a/gas/config/obj-elf.c
+++ b/gas/config/obj-elf.c
@@ -666,7 +666,9 @@ obj_elf_change_section (const char *name,
 	    }
 	}
 
-      if (old_sec == NULL && ((attr & ~(SHF_MASKOS | SHF_MASKPROC))
+      if (old_sec == NULL && ((attr & ~(SHF_LINK_ORDER
+					| SHF_MASKOS
+					| SHF_MASKPROC))
 			      & ~ssect->attr) != 0)
 	{
 	  /* As a GNU extension, we permit a .note section to be
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 41000da1e1..935880cf94 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -7486,7 +7486,7 @@ lang_reset_memory_regions (void)
 
 static void
 gc_section_callback (lang_wild_statement_type *ptr,
-		     struct wildcard_list *sec ATTRIBUTE_UNUSED,
+		     struct wildcard_list *sec,
 		     asection *section,
 		     struct flag_info *sflag_info ATTRIBUTE_UNUSED,
 		     lang_input_statement_type *file ATTRIBUTE_UNUSED,
@@ -7496,6 +7496,8 @@ gc_section_callback (lang_wild_statement_type *ptr,
      should be as well.  */
   if (ptr->keep_sections)
     section->flags |= SEC_KEEP;
+  if (sec)
+    section->pattern = sec->spec.name;
 }
 
 /* Iterate over sections marking them against GC.  */
diff --git a/ld/testsuite/ld-elf/pr26256-1.s b/ld/testsuite/ld-elf/pr26256-1.s
new file mode 100644
index 0000000000..7351f76655
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-1.s
@@ -0,0 +1,20 @@
+	.section	.text.bar,"ax",%progbits
+	.globl	bar
+	.type	bar, %function
+bar:
+	.section __patchable_function_entries,"awo",%progbits,bar
+	.dc.a	.LPFE1
+	.section	.text.bar,"ax",%progbits
+.LPFE1:
+	.byte 0
+	.section	.text._start,"ax",%progbits
+	.globl	_start
+	.type	_start, %function
+_start:
+	.section __patchable_function_entries,"awo",%progbits,_start
+	.dc.a	.LPFE2
+	.section	.text._start,"ax",%progbits
+.LPFE2:
+	.byte 0
+	.section .init.data,"aw",%progbits
+	.byte 0
diff --git a/ld/testsuite/ld-elf/pr26256-1.t b/ld/testsuite/ld-elf/pr26256-1.t
new file mode 100644
index 0000000000..bc5232b0ae
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-1.t
@@ -0,0 +1,9 @@
+SECTIONS
+{
+  .text : { *(.text*) }
+  .init.data :
+  {
+    *(.init.data);
+    *(__patchable_function_entries);
+  }
+}
diff --git a/ld/testsuite/ld-elf/pr26256-1a.d b/ld/testsuite/ld-elf/pr26256-1a.d
new file mode 100644
index 0000000000..025ace0e87
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-1a.d
@@ -0,0 +1,7 @@
+#source: pr26256-1.s
+#ld: -e _start -T pr26256-1.t
+#nm: -n
+
+#...
+[0-9a-f]+ T _start
+#pass
diff --git a/ld/testsuite/ld-elf/pr26256-1b.d b/ld/testsuite/ld-elf/pr26256-1b.d
new file mode 100644
index 0000000000..760c6d82e7
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-1b.d
@@ -0,0 +1,7 @@
+#source: pr26256-1.s
+#ld: -e _start
+#nm: -n
+
+#...
+[0-9a-f]+ T _start
+#pass
diff --git a/ld/testsuite/ld-elf/pr26256-2.s b/ld/testsuite/ld-elf/pr26256-2.s
new file mode 100644
index 0000000000..70e3693f42
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-2.s
@@ -0,0 +1,32 @@
+	.section .text,"ax",%progbits,unique,0
+	.globl text0
+text0:
+	.nop
+	.section .text,"ax",%progbits,unique,1
+	.globl text1
+text1:
+	.nop
+	.section .linkorder,"ao",%progbits,0,unique,0
+	.globl linkorder2
+linkorder2:
+	.byte 0
+	.section .linkorder,"ao",%progbits,text0
+	.globl linkorder0
+linkorder0:
+	.byte 1
+	.section .linkorder,"ao",%progbits,text1
+	.globl linkorder1
+linkorder1:
+	.byte 2
+	.section .linkorder,"a",%progbits
+	.globl linkorder3
+linkorder3:
+	.byte 3
+	.section .linkorder,"ao",%progbits,0,unique,3
+	.globl linkorder4
+linkorder4:
+	.byte 4
+	.text
+	.global _start
+_start:
+	.nop
diff --git a/ld/testsuite/ld-elf/pr26256-2.t b/ld/testsuite/ld-elf/pr26256-2.t
new file mode 100644
index 0000000000..a69c01682e
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-2.t
@@ -0,0 +1,5 @@
+SECTIONS
+{
+  .linkorder : { *(.linkorder.*) }
+  .text : { *(.text) }
+}
diff --git a/ld/testsuite/ld-elf/pr26256-2a.d b/ld/testsuite/ld-elf/pr26256-2a.d
new file mode 100644
index 0000000000..24e8e67ec3
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-2a.d
@@ -0,0 +1,19 @@
+#source: pr26256-2.s
+#ld: -e _start -T pr26256-2.t
+#nm: -n
+
+#...
+[0-9a-f]+ R linkorder2
+#...
+[0-9a-f]+ R linkorder3
+#...
+[0-9a-f]+ R linkorder4
+#...
+[0-9a-f]+ R linkorder0
+#...
+[0-9a-f]+ R linkorder1
+#...
+[0-9a-f]+ T text0
+#...
+[0-9a-f]+ T text1
+#pass
diff --git a/ld/testsuite/ld-elf/pr26256-2b.d b/ld/testsuite/ld-elf/pr26256-2b.d
new file mode 100644
index 0000000000..f9bc557777
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-2b.d
@@ -0,0 +1,19 @@
+#source: pr26256-2.s
+#ld: -e _start
+#nm: -n
+
+#...
+[0-9a-f]+ T text0
+#...
+[0-9a-f]+ T text1
+#...
+[0-9a-f]+ R linkorder2
+#...
+[0-9a-f]+ R linkorder3
+#...
+[0-9a-f]+ R linkorder4
+#...
+[0-9a-f]+ R linkorder0
+#...
+[0-9a-f]+ R linkorder1
+#pass
diff --git a/ld/testsuite/ld-elf/pr26256-3.s b/ld/testsuite/ld-elf/pr26256-3.s
new file mode 100644
index 0000000000..276f9de055
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-3.s
@@ -0,0 +1,18 @@
+	.text
+	.global _start
+_start:
+	.byte 3
+
+	.section .rosection,"a"
+	.byte 9
+
+	.section .text.bar,"a",%progbits
+	.byte 2
+	.section .text.foo,"a",%progbits
+	.byte 1
+	.section .rodata.foo,"ao",%progbits,.text.foo
+	.byte 1
+	.section .rodata.bar,"a",%progbits
+	.byte 2
+	.section .rodata.bar,"ao",%progbits,.text.bar
+	.byte 3
diff --git a/ld/testsuite/ld-elf/pr26256-3a.d b/ld/testsuite/ld-elf/pr26256-3a.d
new file mode 100644
index 0000000000..3cef3a94c0
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-3a.d
@@ -0,0 +1,9 @@
+#source: pr26256-3.s
+#ld: -e _start -T pr26256-3a.t
+#readelf: -x .rodata -x .text
+
+Hex dump of section \'.rodata\':
+  0x[a-f0-9]+ +00010203 +040907 +.+
+
+Hex dump of section \'.text\':
+  0x[a-f0-9]+ +020103 +.+
diff --git a/ld/testsuite/ld-elf/pr26256-3a.t b/ld/testsuite/ld-elf/pr26256-3a.t
new file mode 100644
index 0000000000..7add651a71
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-3a.t
@@ -0,0 +1,13 @@
+SECTIONS
+{
+  .rodata :
+    {
+      BYTE(0)
+      *(.rodata.foo)
+      *(.rodata.bar)
+      BYTE(4)
+      *(.rosection)
+      BYTE(7)
+    }
+  .text : {*(.text.bar) *(.text.foo)}
+}
diff --git a/ld/testsuite/ld-elf/pr26256-3b.d b/ld/testsuite/ld-elf/pr26256-3b.d
new file mode 100644
index 0000000000..031de2de6f
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-3b.d
@@ -0,0 +1,9 @@
+#source: pr26256-3.s
+#ld: -e _start -T pr26256-3b.t
+#readelf: -x .rodata -x .text
+
+Hex dump of section \'.rodata\':
+  0x[a-f0-9]+ +00020301 +040907 +.+
+
+Hex dump of section \'.text\':
+  0x[a-f0-9]+ +020103 +.+
diff --git a/ld/testsuite/ld-elf/pr26256-3b.t b/ld/testsuite/ld-elf/pr26256-3b.t
new file mode 100644
index 0000000000..6f72e93bad
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26256-3b.t
@@ -0,0 +1,12 @@
+SECTIONS
+{
+  .rodata :
+    {
+      BYTE(0)
+      *(.rodata*)
+      BYTE(4)
+      *(.rosection)
+      BYTE(7)
+    }
+  .text : {*(.text.bar) *(.text.foo)}
+}
-- 
2.29.2



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