[PATCH 04/14] x86-64: use BFD_RELOC_32_PLT_PCREL in favor of custom type

[Jan Beulich]

No reason to have a separate type when the generic one has no (other)
meaning for this target.
---
Why is it that BFD_RELOC_386_PLT32 (but not BFD_RELOC_X86_64_PLT32) is
among the types checked in TC_FORCE_RELOCATION_LOCAL()? Without that, the
type could also be replaced by BFD_RELOC_32_PLT_PCREL, then even
simplifying a couple of expressions.

Code and comment in tc_i386_fix_adjustable() as well as the conditional
in i386_validate_fix() suggest that PLT32 relocs can also be absolute.
The relocation types (32- and 64-bit) are clearly specified as PC-
relative, though. What's the deal? (Questionable commit is 1b714c14e40f
["x86: Turn PLT32 to PC32 only for PC-relative relocations"].) PR
gas/32196 really pointed at a bigger problem: If the programmer says @plt,
a PLT32 relocation ought to be generated, no matter what. Just like for
any of the other @... relocation modifiers. Dropping the relocation is an
optimization, which ought to not be active by default.

--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -3881,7 +3881,6 @@ enum bfd_reloc_code_real
 
   /* x86-64/elf relocations.  */
   BFD_RELOC_X86_64_GOT32,
-  BFD_RELOC_X86_64_PLT32,
   BFD_RELOC_X86_64_COPY,
   BFD_RELOC_X86_64_GLOB_DAT,
   BFD_RELOC_X86_64_JUMP_SLOT,
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -233,7 +233,7 @@ static const struct elf_reloc_map x86_64
   { BFD_RELOC_64,		R_X86_64_64,   },
   { BFD_RELOC_32_PCREL,		R_X86_64_PC32, },
   { BFD_RELOC_X86_64_GOT32,	R_X86_64_GOT32,},
-  { BFD_RELOC_X86_64_PLT32,	R_X86_64_PLT32,},
+  { BFD_RELOC_32_PLT_PCREL,	R_X86_64_PLT32,},
   { BFD_RELOC_X86_64_COPY,	R_X86_64_COPY, },
   { BFD_RELOC_X86_64_GLOB_DAT,	R_X86_64_GLOB_DAT, },
   { BFD_RELOC_X86_64_JUMP_SLOT, R_X86_64_JUMP_SLOT, },
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -1445,7 +1445,6 @@ static const char *const bfd_reloc_code_
   "BFD_RELOC_386_IRELATIVE",
   "BFD_RELOC_386_GOT32X",
   "BFD_RELOC_X86_64_GOT32",
-  "BFD_RELOC_X86_64_PLT32",
   "BFD_RELOC_X86_64_COPY",
   "BFD_RELOC_X86_64_GLOB_DAT",
   "BFD_RELOC_X86_64_JUMP_SLOT",
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -2416,8 +2416,6 @@ ENUMDOC
 ENUM
   BFD_RELOC_X86_64_GOT32
 ENUMX
-  BFD_RELOC_X86_64_PLT32
-ENUMX
   BFD_RELOC_X86_64_COPY
 ENUMX
   BFD_RELOC_X86_64_GLOB_DAT
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -1396,7 +1396,7 @@ gotrel[] =
 				       BFD_RELOC_64_PLTOFF },
     { .bitfield = { .imm64 = 1 } }, true },
     { STRING_COMMA_LEN ("PLT"),      { BFD_RELOC_386_PLT32,
-				       BFD_RELOC_X86_64_PLT32    },
+				       BFD_RELOC_32_PLT_PCREL },
     OPERAND_TYPE_IMM32_32S_DISP32, false },
     { STRING_COMMA_LEN ("GOTPLT"),   { _dummy_first_bfd_reloc_code_real,
 				       BFD_RELOC_X86_64_GOTPLT64 },
@@ -4138,7 +4138,7 @@ tc_i386_fix_adjustable (fixS *fixP)
   /* Resolve PLT32 relocation against local symbol to section only for
      PC-relative relocations.  */
   if (fixP->fx_r_type == BFD_RELOC_386_PLT32
-      || fixP->fx_r_type == BFD_RELOC_X86_64_PLT32)
+      || fixP->fx_r_type == BFD_RELOC_32_PLT_PCREL)
     return fixP->fx_pcrel;
   return 1;
 }
@@ -11778,7 +11778,7 @@ output_jump (void)
   if (flag_code == CODE_64BIT && size == 4
       && jump_reloc == NO_RELOC && i.op[0].disps->X_add_number == 0
       && need_plt32_p (i.op[0].disps->X_add_symbol))
-    jump_reloc = BFD_RELOC_X86_64_PLT32;
+    jump_reloc = BFD_RELOC_32_PLT_PCREL;
 #endif
 
   jump_reloc = reloc (size, 1, 1, jump_reloc);
@@ -13424,7 +13424,7 @@ x86_cons (expressionS *exp, int size)
 	      *input_line_pointer = c;
 	    }
 	  else if ((got_reloc == BFD_RELOC_386_PLT32
-		    || got_reloc == BFD_RELOC_X86_64_PLT32)
+		    || got_reloc == BFD_RELOC_32_PLT_PCREL)
 		   && exp->X_op != O_symbol)
 	    {
 	      char c = *input_line_pointer;
@@ -15768,7 +15768,7 @@ elf_symbol_resolved_in_segment_p (symbol
     switch ((enum bfd_reloc_code_real) fr_var)
       {
       case BFD_RELOC_386_PLT32:
-      case BFD_RELOC_X86_64_PLT32:
+      case BFD_RELOC_32_PLT_PCREL:
 	/* Symbol with PLT relocation may be preempted. */
 	return 0;
       default:
@@ -16229,7 +16229,7 @@ md_estimate_size_before_relax (fragS *fr
 	  && fragP->tc_frag_data.code == CODE_64BIT
 	  && fragP->fr_offset == 0
 	  && need_plt32_p (fragP->fr_symbol))
-	reloc_type = BFD_RELOC_X86_64_PLT32;
+	reloc_type = BFD_RELOC_32_PLT_PCREL;
 #endif
 
       old_fr_fix = fragP->fr_fix;
@@ -16633,7 +16633,7 @@ md_apply_fix (fixS *fixP, valueT *valP,
     switch (fixP->fx_r_type)
       {
       case BFD_RELOC_386_PLT32:
-      case BFD_RELOC_X86_64_PLT32:
+      case BFD_RELOC_32_PLT_PCREL:
 	/* Make the jump instruction point to the address of the operand.
 	   At runtime we merely add the offset to the actual PLT entry.
 	   NB: Subtract the offset size only for jump instructions.  */
@@ -18350,7 +18350,7 @@ i386_validate_fix (fixS *fixp)
       if (fixp->fx_addsy
 	  && fixp->fx_pcrel
 	  && (fixp->fx_r_type == BFD_RELOC_386_PLT32
-	      || fixp->fx_r_type == BFD_RELOC_X86_64_PLT32)
+	      || fixp->fx_r_type == BFD_RELOC_32_PLT_PCREL)
 	  && symbol_section_p (fixp->fx_addsy))
 	fixp->fx_r_type = BFD_RELOC_32_PCREL;
       if (!object_64bit)
@@ -18426,7 +18426,7 @@ tc_gen_reloc (asection *section ATTRIBUT
 #endif
       /* Fall through.  */
 
-    case BFD_RELOC_X86_64_PLT32:
+    case BFD_RELOC_32_PLT_PCREL:
     case BFD_RELOC_X86_64_GOT32:
     case BFD_RELOC_X86_64_GOTPCREL:
     case BFD_RELOC_X86_64_GOTPCRELX:
@@ -18593,7 +18593,7 @@ tc_gen_reloc (asection *section ATTRIBUT
       else
 	switch (code)
 	  {
-	  case BFD_RELOC_X86_64_PLT32:
+	  case BFD_RELOC_32_PLT_PCREL:
 	  case BFD_RELOC_X86_64_GOT32:
 	  case BFD_RELOC_X86_64_GOTPCREL:
 	  case BFD_RELOC_X86_64_GOTPCRELX: