or1k: Support large plt_relocs when generating plt entries

The current PLT generation code will generate invalid code when the PLT
relocation offset exceeds 64k.  This fixes the issue by detecting large
plt_reloc offsets and generare code sequences to create larger plt
relocations.

The "large" plt code needs 2 extra instructions to create 32-bit offsets.

bfd/ChangeLog:

	PR 27746
	* elf32-or1k.c (PLT_ENTRY_SIZE_LARGE, PLT_MAX_INSN_COUNT,
	OR1K_ADD, OR1K_ORI): New macros to help with plt creation.
	(elf_or1k_link_hash_table): New field plt_count.
	(elf_or1k_link_hash_entry): New field plt_index.
	(elf_or1k_plt_entry_size): New function.
	(or1k_write_plt_entry): Update to support variable size PLTs.
	(or1k_elf_finish_dynamic_sections): Use new or1k_write_plt_entry
	API.
	(or1k_elf_finish_dynamic_symbol): Update to write large PLTs
	when needed.
	(allocate_dynrelocs): Use elf_or1k_plt_entry_size to account for
	PLT size.

ld/ChangeLog:

	PR 27746
	testsuite/ld-or1k/or1k.exp (or1kplttests): Add tests for linking
	along with gotha() relocations.
	testsuite/ld-or1k/gotha1.dd: New file.
	testsuite/ld-or1k/gotha1.s: New file.
	testsuite/ld-or1k/gotha2.dd: New file.
	testsuite/ld-or1k/gotha2.s: New file
	testsuite/ld-or1k/pltlib.s (x): Define size to avoid link
	failure.

2 files changed, 126 insertions, 39 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 8293e9d..8508453 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,21 @@
 2021-05-06  Stafford Horne  <shorne@gmail.com>
 
+	PR 27746
+	* elf32-or1k.c (PLT_ENTRY_SIZE_LARGE, PLT_MAX_INSN_COUNT,
+	OR1K_ADD, OR1K_ORI): New macros to help with plt creation.
+	(elf_or1k_link_hash_table): New field plt_count.
+	(elf_or1k_link_hash_entry): New field plt_index.
+	(elf_or1k_plt_entry_size): New function.
+	(or1k_write_plt_entry): Update to support variable size PLTs.
+	(or1k_elf_finish_dynamic_sections): Use new or1k_write_plt_entry
+	API.
+	(or1k_elf_finish_dynamic_symbol): Update to write large PLTs
+	when needed.
+	(allocate_dynrelocs): Use elf_or1k_plt_entry_size to account for
+	PLT size.
+
+2021-05-06  Stafford Horne  <shorne@gmail.com>
+
 	PR 21464
 	* elf32-or1k.c (or1k_elf_relocate_section): Relax R_OR1K_GOT16
 	overflow check if we have R_OR1K_GOT_AHI16 followed by
diff --git a/bfd/elf32-or1k.c b/bfd/elf32-or1k.c
index 5eca430..4ae7f32 100644
--- a/bfd/elf32-or1k.c
+++ b/bfd/elf32-or1k.c
@@ -30,10 +30,14 @@
 #define N_ONES(X)	(((bfd_vma)2 << (X)) - 1)
 
 #define PLT_ENTRY_SIZE 16
+#define PLT_ENTRY_SIZE_LARGE (6*4)
+#define PLT_MAX_INSN_COUNT 6
 
 #define OR1K_MOVHI(D)		(0x18000000 | (D << 21))
 #define OR1K_ADRP(D)		(0x08000000 | (D << 21))
 #define OR1K_LWZ(D,A)		(0x84000000 | (D << 21) | (A << 16))
+#define OR1K_ADD(D,A,B)		(0xE0000000 | (D << 21) | (A << 16) | (B << 11))
+#define OR1K_ORI(D,A)		(0xA8000000 | (D << 21) | (A << 16))
 #define OR1K_ORI0(D)		(0xA8000000 | (D << 21))
 #define OR1K_JR(B)		(0x44000000 | (B << 11))
 #define OR1K_NOP		0x15000000
@@ -907,6 +911,8 @@ struct elf_or1k_link_hash_entry
 {
   struct elf_link_hash_entry root;
 
+  /* For calculating PLT size.  */
+  bfd_vma plt_index;
   /* Track type of TLS access.  */
   unsigned char tls_type;
 };
@@ -931,9 +937,20 @@ struct elf_or1k_link_hash_table
 {
   struct elf_link_hash_table root;
 
+  bfd_vma plt_count;
   bool saw_plta;
 };
 
+static size_t
+elf_or1k_plt_entry_size (bfd_vma plt_index)
+{
+  bfd_vma plt_reloc;
+
+  plt_reloc = plt_index * sizeof (Elf32_External_Rela);
+
+  return (plt_reloc > 0xffff) ? PLT_ENTRY_SIZE_LARGE : PLT_ENTRY_SIZE;
+}
+
 /* Get the ELF linker hash table from a link_info structure.  */
 #define or1k_elf_hash_table(p) \
   ((is_elf_hash_table ((p)->hash)					\
@@ -2222,33 +2239,46 @@ or1k_elf_check_relocs (bfd *abfd,
 }
 
 static void
-or1k_write_plt_entry (bfd *output_bfd, bfd_byte *contents, unsigned insn1,
-		      unsigned insn2, unsigned insn3, unsigned insnj)
+or1k_write_plt_entry (bfd *output_bfd, bfd_byte *contents, unsigned insnj,
+		      unsigned insns[], size_t insn_count)
 {
   unsigned nodelay = elf_elfheader (output_bfd)->e_flags & EF_OR1K_NODELAY;
-  unsigned insn4;
+  unsigned output_insns[PLT_MAX_INSN_COUNT];
+
+  /* Copy instructions into the output buffer.  */
+  for (size_t i = 0; i < insn_count; i++)
+    output_insns[i] = insns[i];
 
   /* Honor the no-delay-slot setting.  */
-  if (insn3 == OR1K_NOP)
+  if (insns[insn_count-1] == OR1K_NOP)
     {
-      insn4 = insn3;
+      unsigned slot1, slot2;
+
       if (nodelay)
-	insn3 = insnj;
+	slot1 = insns[insn_count-2], slot2 = insnj;
       else
-	insn3 = insn2, insn2 = insnj;
+	slot1 = insnj, slot2 = insns[insn_count-2];
+
+      output_insns[insn_count-2] = slot1;
+      output_insns[insn_count-1] = slot2;
+      output_insns[insn_count]   = OR1K_NOP;
     }
   else
     {
+      unsigned slot1, slot2;
+
       if (nodelay)
-	insn4 = insnj;
+	slot1 = insns[insn_count-1], slot2 = insnj;
       else
-	insn4 = insn3, insn3 = insnj;
+	slot1 = insnj, slot2 = insns[insn_count-1];
+
+      output_insns[insn_count-1] = slot1;
+      output_insns[insn_count]   = slot2;
     }
 
-  bfd_put_32 (output_bfd, insn1, contents);
-  bfd_put_32 (output_bfd, insn2, contents + 4);
-  bfd_put_32 (output_bfd, insn3, contents + 8);
-  bfd_put_32 (output_bfd, insn4, contents + 12);
+  /* Write out the output buffer.  */
+  for (size_t i = 0; i < (insn_count+1); i++)
+    bfd_put_32 (output_bfd, output_insns[i], contents + (i*4));
 }
 
 /* Finish up the dynamic sections.  */
@@ -2315,7 +2345,8 @@ or1k_elf_finish_dynamic_sections (bfd *output_bfd,
       splt = htab->root.splt;
       if (splt && splt->size > 0)
 	{
-	  unsigned plt0, plt1, plt2;
+	  unsigned plt[PLT_MAX_INSN_COUNT];
+	  size_t plt_insn_count = 3;
 	  bfd_vma got_addr = sgot->output_section->vma + sgot->output_offset;
 
 	  /* Note we force 16 byte alignment on the .got, so that
@@ -2326,27 +2357,27 @@ or1k_elf_finish_dynamic_sections (bfd *output_bfd,
 	      bfd_vma pc = splt->output_section->vma + splt->output_offset;
 	      unsigned pa = ((got_addr >> 13) - (pc >> 13)) & 0x1fffff;
 	      unsigned po = got_addr & 0x1fff;
-	      plt0 = OR1K_ADRP(12) | pa;
-	      plt1 = OR1K_LWZ(15,12) | (po + 8);
-	      plt2 = OR1K_LWZ(12,12) | (po + 4);
+	      plt[0] = OR1K_ADRP(12) | pa;
+	      plt[1] = OR1K_LWZ(15,12) | (po + 8);
+	      plt[2] = OR1K_LWZ(12,12) | (po + 4);
 	    }
 	  else if (bfd_link_pic (info))
 	    {
-	      plt0 = OR1K_LWZ(15, 16) | 8;	/* .got+8 */
-	      plt1 = OR1K_LWZ(12, 16) | 4;	/* .got+4 */
-	      plt2 = OR1K_NOP;
+	      plt[0] = OR1K_LWZ(15, 16) | 8;	/* .got+8 */
+	      plt[1] = OR1K_LWZ(12, 16) | 4;	/* .got+4 */
+	      plt[2] = OR1K_NOP;
 	    }
 	  else
 	    {
 	      unsigned ha = ((got_addr + 0x8000) >> 16) & 0xffff;
 	      unsigned lo = got_addr & 0xffff;
-	      plt0 = OR1K_MOVHI(12) | ha;
-	      plt1 = OR1K_LWZ(15,12) | (lo + 8);
-	      plt2 = OR1K_LWZ(12,12) | (lo + 4);
+	      plt[0] = OR1K_MOVHI(12) | ha;
+	      plt[1] = OR1K_LWZ(15,12) | (lo + 8);
+	      plt[2] = OR1K_LWZ(12,12) | (lo + 4);
 	    }
 
-	  or1k_write_plt_entry (output_bfd, splt->contents,
-				plt0, plt1, plt2, OR1K_JR(15));
+	  or1k_write_plt_entry (output_bfd, splt->contents, OR1K_JR(15),
+				plt, plt_insn_count);
 
 	  elf_section_data (splt->output_section)->this_hdr.sh_entsize = 4;
 	}
@@ -2389,7 +2420,8 @@ or1k_elf_finish_dynamic_symbol (bfd *output_bfd,
 
   if (h->plt.offset != (bfd_vma) -1)
     {
-      unsigned int plt0, plt1, plt2;
+      unsigned int plt[PLT_MAX_INSN_COUNT];
+      size_t plt_insn_count = 3;
       asection *splt;
       asection *sgot;
       asection *srela;
@@ -2401,6 +2433,7 @@ or1k_elf_finish_dynamic_symbol (bfd *output_bfd,
       bfd_vma got_offset;
       bfd_vma got_addr;
       Elf_Internal_Rela rela;
+      bool large_plt_entry;
 
       /* This symbol has an entry in the procedure linkage table.  Set
 	 it up.  */
@@ -2418,10 +2451,13 @@ or1k_elf_finish_dynamic_symbol (bfd *output_bfd,
 	 corresponds to this symbol.  This is the index of this symbol
 	 in all the symbols for which we are making plt entries.  The
 	 first entry in the procedure linkage table is reserved.  */
-      plt_index = h->plt.offset / PLT_ENTRY_SIZE - 1;
+      plt_index = ((struct elf_or1k_link_hash_entry *) h)->plt_index;
       plt_addr = plt_base_addr + h->plt.offset;
       plt_reloc = plt_index * sizeof (Elf32_External_Rela);
 
+      large_plt_entry = (elf_or1k_plt_entry_size (plt_index)
+			 == PLT_ENTRY_SIZE_LARGE);
+
       /* Get the offset into the .got table of the entry that
 	corresponds to this function.  Each .got entry is 4 bytes.
 	The first three are reserved.  */
@@ -2433,27 +2469,57 @@ or1k_elf_finish_dynamic_symbol (bfd *output_bfd,
 	{
 	  unsigned pa = ((got_addr >> 13) - (plt_addr >> 13)) & 0x1fffff;
 	  unsigned po = (got_addr & 0x1fff);
-	  plt0 = OR1K_ADRP(12) | pa;
-	  plt1 = OR1K_LWZ(12,12) | po;
-	  plt2 = OR1K_ORI0(11) | plt_reloc;
+	  plt[0] = OR1K_ADRP(12) | pa;
+	  plt[1] = OR1K_LWZ(12,12) | po;
+	  plt[2] = OR1K_ORI0(11) | plt_reloc;
 	}
       else if (bfd_link_pic (info))
 	{
-	  plt0 = OR1K_LWZ(12,16) | got_offset;
-	  plt1 = OR1K_ORI0(11) | plt_reloc;
-	  plt2 = OR1K_NOP;
+	  if (large_plt_entry)
+	    {
+	      unsigned gotha = ((got_offset + 0x8000) >> 16) & 0xffff;
+	      unsigned got = got_offset & 0xffff;
+	      unsigned pltrelhi = (plt_reloc >> 16) & 0xffff;
+	      unsigned pltrello = plt_reloc & 0xffff;
+
+	      plt[0] = OR1K_MOVHI(12) | gotha;
+	      plt[1] = OR1K_ADD(12,12,16);
+	      plt[2] = OR1K_LWZ(12,12) | got;
+	      plt[3] = OR1K_MOVHI(11) | pltrelhi;
+	      plt[4] = OR1K_ORI(11,11) | pltrello;
+	      plt_insn_count = 5;
+	    }
+	  else
+	    {
+	      plt[0] = OR1K_LWZ(12,16) | got_offset;
+	      plt[1] = OR1K_ORI0(11) | plt_reloc;
+	      plt[2] = OR1K_NOP;
+	    }
 	}
       else
 	{
 	  unsigned ha = ((got_addr + 0x8000) >> 16) & 0xffff;
 	  unsigned lo = got_addr & 0xffff;
-	  plt0 = OR1K_MOVHI(12) | ha;
-	  plt1 = OR1K_LWZ(12,12) | lo;
-	  plt2 = OR1K_ORI0(11) | plt_reloc;
+	  plt[0] = OR1K_MOVHI(12) | ha;
+	  plt[1] = OR1K_LWZ(12,12) | lo;
+	  plt[2] = OR1K_ORI0(11) | plt_reloc;
+	}
+
+      /* For large code model we fixup the non-PIC PLT relocation instructions
+	 here.  */
+      if (large_plt_entry && !bfd_link_pic (info))
+	{
+	  unsigned pltrelhi = (plt_reloc >> 16) & 0xffff;
+	  unsigned pltrello = plt_reloc & 0xffff;
+
+	  plt[2] = OR1K_MOVHI(11) | pltrelhi;
+	  plt[3] = OR1K_ORI(11,11) | pltrello;
+	  plt[4] = OR1K_NOP;
+	  plt_insn_count = 5;
 	}
 
       or1k_write_plt_entry (output_bfd, splt->contents + h->plt.offset,
-			    plt0, plt1, plt2, OR1K_JR(12));
+			    OR1K_JR(12), plt, plt_insn_count);
 
       /* Fill in the entry in the global offset table.  We initialize it to
 	 point to the top of the plt.  This is done to lazy lookup the actual
@@ -2777,11 +2843,16 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf)
       if (WILL_CALL_FINISH_DYNAMIC_SYMBOL (1, bfd_link_pic (info), h))
 	{
 	  asection *splt = htab->root.splt;
+	  bfd_vma plt_index;
+
+	  /* Track the index of our plt entry for use in calculating size.  */
+	  plt_index = htab->plt_count++;
+	  ((struct elf_or1k_link_hash_entry *) h)->plt_index = plt_index;
 
 	  /* If this is the first .plt entry, make room for the special
 	     first entry.  */
 	  if (splt->size == 0)
-	    splt->size = PLT_ENTRY_SIZE;
+	    splt->size = elf_or1k_plt_entry_size (plt_index);
 
 	  h->plt.offset = splt->size;
 
@@ -2798,7 +2869,7 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf)
 	    }
 
 	  /* Make room for this entry.  */
-	  splt->size += PLT_ENTRY_SIZE;
+	  splt->size += elf_or1k_plt_entry_size (plt_index);
 
 	  /* We also need to make an entry in the .got.plt section, which
 	     will be placed in the .got section by the linker script.  */