Add support for COFF secidx relocations

bfd	* coff-i386.c (in_reloc_p): Add R_SECTION.
	(howto_table): Add R_SECTION.
	(coff_pe_i386_relocation_section): Add support for R_SECTION.
	(coff_i386_reloc_type_lookup): Add support for
	BFD_RELOC_16_SECCIDX.
	* coff-x86_64.c (in_reloc_p): Add R_SECTION.
	(howto_table): Add R_SECTION.
	(coff_pe_amd64_relocation_section): Add support for R_SECTION.
	(coff_amd64_reloc_type_lookup): Add support for
	BFD_RELOC_16_SECCIDX.
	* reloc.c: Add BFD_RELOC_16_SECIDX.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.

gas	* config/tc-i386.c (pe_directive_secidx): New function.
	(md_pseudo_table): Add support for secidx.
	(x86_cons_fix_new): Likewise.
	(tc_gen_reloc): Likewise.
	* expr.c (op_rank): Add O_secidx.
	* expr.h (operatorT): Likewise.
	* symbols.c (resolve_symbol_value): Add support for O_secidx.
	* testsuite/gas/i386/secidx.s: New test source file.
	* testsuite/gas/i386/secidx.d: New test driver file.
	* testsuite/gas/i386/i386.exp: Run new test.

include	* coff/i386.h: Define R_SECTION.
	* coff/x86_64.h: Likewise.

ld	* testsuite/ld-pe/secidx1.s: New test source file.
	* testsuite/ld-pe/secidx2.s: New test source file.
	* testsuite/ld-pe/secidx.d: New test driver file.
	* testsuite/ld-pe/secidx_64.d: New test driver file.
	* testsuite/ld-pe/pe.exp: Add new tests.

8 files changed, 192 insertions, 23 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 54abdfb..63fcc53 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,16 @@
+2022-04-07  Mark Harmstone  <mark@harmstone.com>
+
+	* config/tc-i386.c (pe_directive_secidx): New function.
+	(md_pseudo_table): Add support for secidx.
+	(x86_cons_fix_new): Likewise.
+	(tc_gen_reloc): Likewise.
+	* expr.c (op_rank): Add O_secidx.
+	* expr.h (operatorT): Likewise.
+	* symbols.c (resolve_symbol_value): Add support for O_secidx.
+	* testsuite/gas/i386/secidx.s: New test source file.
+	* testsuite/gas/i386/secidx.d: New test driver file.
+	* testsuite/gas/i386/i386.exp: Run new test.
+
 2022-04-07  Andreas Krebbel  <krebbel@linux.ibm.com>
 
 	* config/tc-s390.c (s390_parse_cpu): Add z16 as alternate CPU
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 7617792..c2678ea 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -152,6 +152,7 @@ static void set_check (int);
 static void set_cpu_arch (int);
 #ifdef TE_PE
 static void pe_directive_secrel (int);
+static void pe_directive_secidx (int);
 #endif
 static void signed_cons (int);
 static char *output_invalid (int c);
@@ -1385,6 +1386,7 @@ const pseudo_typeS md_pseudo_table[] =
 #endif
 #ifdef TE_PE
   {"secrel32", pe_directive_secrel, 0},
+  {"secidx", pe_directive_secidx, 0},
 #endif
   {0, 0, 0}
 };
@@ -10267,6 +10269,8 @@ x86_cons_fix_new (fragS *frag, unsigned int off, unsigned int len,
       exp->X_op = O_symbol;
       r = BFD_RELOC_32_SECREL;
     }
+  else if (exp->X_op == O_secidx)
+    r = BFD_RELOC_16_SECIDX;
 #endif
 
   fix_new_exp (frag, off, len, exp, 0, r);
@@ -10306,13 +10310,16 @@ lex_got (enum bfd_reloc_code_real *rel,
      we don't yet know the operand size (this will be set by insn
      matching).  Hence we record the word32 relocation here,
      and adjust the reloc according to the real size in reloc().  */
-  static const struct {
+  static const struct
+  {
     const char *str;
     int len;
     const enum bfd_reloc_code_real rel[2];
     const i386_operand_type types64;
     bool need_GOT_symbol;
-  } gotrel[] = {
+  }
+    gotrel[] =
+  {
 #ifndef TE_PE
 #if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
     { STRING_COMMA_LEN ("SIZE"),      { BFD_RELOC_SIZE32,
@@ -10557,6 +10564,25 @@ pe_directive_secrel (int dummy ATTRIBUTE_UNUSED)
   input_line_pointer--;
   demand_empty_rest_of_line ();
 }
+
+static void
+pe_directive_secidx (int dummy ATTRIBUTE_UNUSED)
+{
+  expressionS exp;
+
+  do
+    {
+      expression (&exp);
+      if (exp.X_op == O_symbol)
+	exp.X_op = O_secidx;
+
+      emit_expr (&exp, 2);
+    }
+  while (*input_line_pointer++ == ',');
+
+  input_line_pointer--;
+  demand_empty_rest_of_line ();
+}
 #endif
 
 /* Handle Vector operations.  */
@@ -14359,6 +14385,7 @@ tc_gen_reloc (asection *section ATTRIBUTE_UNUSED, fixS *fixp)
     case BFD_RELOC_VTABLE_INHERIT:
 #ifdef TE_PE
     case BFD_RELOC_32_SECREL:
+    case BFD_RELOC_16_SECIDX:
 #endif
       code = fixp->fx_r_type;
       break;
diff --git a/gas/expr.c b/gas/expr.c
index 2341343..6ad8bee 100644
--- a/gas/expr.c
+++ b/gas/expr.c
@@ -1522,6 +1522,7 @@ static operator_rankT op_rank[O_max] = {
   0,	/* O_constant */
   0,	/* O_symbol */
   0,	/* O_symbol_rva */
+  0,	/* O_secidx */
   0,	/* O_register */
   0,	/* O_big */
   9,	/* O_uminus */
diff --git a/gas/expr.h b/gas/expr.h
index 3471e7c..dff4085 100644
--- a/gas/expr.h
+++ b/gas/expr.h
@@ -18,28 +18,27 @@
    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
    02110-1301, USA.  */
 
-/*
- * By popular demand, we define a struct to represent an expression.
- * This will no doubt mutate as expressions become baroque.
- *
- * Currently, we support expressions like "foo OP bar + 42".  In other
- * words we permit a (possibly undefined) symbol, a (possibly
- * undefined) symbol and the operation used to combine the symbols,
- * and an (absolute) augend.  RMS says this is so we can have 1-pass
- * assembly for any compiler emissions, and a 'case' statement might
- * emit 'undefined1 - undefined2'.
- *
- * The type of an expression used to be stored as a segment.  That got
- * confusing because it overloaded the concept of a segment.  I added
- * an operator field, instead.
- */
+/* By popular demand, we define a struct to represent an expression.
+   This will no doubt mutate as expressions become baroque.
+
+   Currently, we support expressions like "foo OP bar + 42".  In other
+   words we permit a (possibly undefined) symbol, a (possibly
+   undefined) symbol and the operation used to combine the symbols,
+   and an (absolute) augend.  RMS says this is so we can have 1-pass
+   assembly for any compiler emissions, and a 'case' statement might
+   emit 'undefined1 - undefined2'.
+
+   The type of an expression used to be stored as a segment.  That got
+   confusing because it overloaded the concept of a segment.  I added
+   an operator field, instead.  */
 
 /* This is the type of an expression.  The operator types are also
    used while parsing an expression.
 
    NOTE: This enumeration must match the op_rank array in expr.c.  */
 
-typedef enum {
+typedef enum
+{
   /* An illegal expression.  */
   O_illegal,
   /* A nonexistent expression.  */
@@ -50,6 +49,8 @@ typedef enum {
   O_symbol,
   /* X_add_symbol + X_add_number - the base address of the image.  */
   O_symbol_rva,
+  /* The section index of X_add_symbol.  */
+  O_secidx,
   /* A register (X_add_number is register number).  */
   O_register,
   /* A big value.  If X_add_number is negative or 0, the value is in
@@ -112,7 +113,8 @@ typedef enum {
   O_max
 } operatorT;
 
-typedef struct expressionS {
+typedef struct expressionS
+{
   /* The main symbol.  */
   symbolS *X_add_symbol;
   /* The second symbol, if needed.  */
@@ -182,12 +184,10 @@ extern unsigned int get_single_number (void);
 extern symbolS *make_expr_symbol (expressionS * expressionP);
 extern int expr_symbol_where (symbolS *, const char **, unsigned int *);
 extern void current_location (expressionS *);
-
 extern symbolS *expr_build_uconstant (offsetT);
 extern symbolS *expr_build_dot (void);
 extern uint32_t generic_bignum_to_int32 (void);
 extern uint64_t generic_bignum_to_int64 (void);
-
-int resolve_expression (expressionS *);
+extern int resolve_expression (expressionS *);
 
 extern bool literal_prefix_dollar_hex;
diff --git a/gas/symbols.c b/gas/symbols.c
index b35c6d2..fb480be 100644
--- a/gas/symbols.c
+++ b/gas/symbols.c
@@ -1364,6 +1364,7 @@ resolve_symbol_value (symbolS *symp)
 
 	case O_symbol:
 	case O_symbol_rva:
+	case O_secidx:
 	  left = resolve_symbol_value (add_symbol);
 	  seg_left = S_GET_SEGMENT (add_symbol);
 	  if (finalize_syms)
@@ -1444,6 +1445,13 @@ resolve_symbol_value (symbolS *symp)
 	      final_val += symp->frag->fr_address + left;
 	      resolved = symbol_resolved_p (add_symbol);
 	      symp->flags.resolving = 0;
+
+	      if (op == O_secidx && seg_left != undefined_section)
+		{
+		  final_val = 0;
+		  break;
+		}
+
 	      goto exit_dont_set_value;
 	    }
 	  else
diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index 96356d3..2c84ccc 100644
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -703,11 +703,12 @@ if [gas_32_check] then {
 	}
     }
 
-    # This is a PE specific test.
+    # These are PE specific tests.
     if { [istarget "*-*-cygwin*"] || [istarget "*-*-pe"]
 	 || [istarget "*-*-mingw*"]
     } then {
 	run_dump_test "secrel"
+	run_dump_test "secidx"
     }
 
     # Miscellaneous tests.
diff --git a/gas/testsuite/gas/i386/secidx.d b/gas/testsuite/gas/i386/secidx.d
new file mode 100644
index 0000000..baf299f
--- /dev/null
+++ b/gas/testsuite/gas/i386/secidx.d
@@ -0,0 +1,40 @@
+#objdump: -rs
+#name: i386 secidx reloc
+
+.*: +file format pe-i386
+
+RELOCATION RECORDS FOR \[\.data\]:
+OFFSET[ 	]+TYPE[ 	]+VALUE 
+0+24 secidx            \.text
+0+27 secidx            \.text
+0+2a secidx            \.text
+0+2d secidx            \.text
+0+3c secidx            \.data
+0+3f secidx            \.data
+0+42 secidx            \.data
+0+45 secidx            \.data
+0+54 secidx            \.rdata
+0+57 secidx            \.rdata
+0+5a secidx            \.rdata
+0+5d secidx            \.rdata
+0+6c secidx            ext24
+0+6f secidx            ext2d
+0+72 secidx            ext36
+0+75 secidx            ext3f
+
+Contents of section \.text:
+ 0000 3e3e3e3e 3c3c3c3c 3e3e3e3e 3e3c3c3c  >>>><<<<>>>>><<<
+ 0010 3e3e3e3e 3e3e3c3c 3e3e3e3e 3e3e3e3c  >>>>>><<>>>>>>><
+Contents of section \.data:
+ 0000 3e3e3e3e 3c3c3c3c 3e3e3e3e 3e3c3c3c  >>>><<<<>>>>><<<
+ 0010 3e3e3e3e 3e3e3c3c 3e3e3e3e 3e3e3e3c  >>>>>><<>>>>>>><
+ 0020 3e3e3e3e 00001100 00110000 11000011  >>>>............
+ 0030 3c3c3c3c 3c3c3c3c 3e3e3e3e 00001100  <<<<<<<<>>>>....
+ 0040 00110000 11000011 3c3c3c3c 3c3c3c3c  ........<<<<<<<<
+ 0050 3e3e3e3e 00001100 00110000 11000011  >>>>............
+ 0060 3c3c3c3c 3c3c3c3c 3e3e3e3e 00001100  <<<<<<<<>>>>....
+ 0070 00110000 11000011 3c3c3c3c 3c3c3c3c  ........<<<<<<<<
+Contents of section \.rdata:
+ 0000 3e3e3e3e 3c3c3c3c 3e3e3e3e 3e3c3c3c  >>>><<<<>>>>><<<
+ 0010 3e3e3e3e 3e3e3c3c 3e3e3e3e 3e3e3e3c  >>>>>><<>>>>>>><
+ 0020 3e3e3e3e 00000000 00000000 00000000  >>>>............
diff --git a/gas/testsuite/gas/i386/secidx.s b/gas/testsuite/gas/i386/secidx.s
new file mode 100644
index 0000000..7ac1d2c
--- /dev/null
+++ b/gas/testsuite/gas/i386/secidx.s
@@ -0,0 +1,79 @@
+.text
+
+	.ascii ">>>>"
+pre04:	.ascii "<<<<"
+	.ascii ">>>>>"
+pre0d:	.ascii "<<<"
+	.ascii ">>>>>>"
+pre16:	.ascii "<<"
+	.ascii ">>>>>>>"
+pre1f:	.ascii "<"
+
+.data
+
+	.ascii ">>>>"
+sam04:	.ascii "<<<<"
+	.ascii ">>>>>"
+sam0d:	.ascii "<<<"
+	.ascii ">>>>>>"
+sam16:	.ascii "<<"
+	.ascii ">>>>>>>"
+sam1f:	.ascii "<"
+
+	.ascii ">>>>"
+	.secidx pre04
+	.byte 0x11
+	.secidx pre0d
+	.byte 0x11
+	.secidx pre16
+	.byte 0x11
+	.secidx pre1f
+	.byte 0x11
+	.ascii "<<<<<<<<"
+
+	.ascii ">>>>"
+	.secidx sam04
+	.byte 0x11
+	.secidx sam0d
+	.byte 0x11
+	.secidx sam16
+	.byte 0x11
+	.secidx sam1f
+	.byte 0x11
+	.ascii "<<<<<<<<"
+
+	.ascii ">>>>"
+	.secidx nex04
+	.byte 0x11
+	.secidx nex0d
+	.byte 0x11
+	.secidx nex16
+	.byte 0x11
+	.secidx nex1f
+	.byte 0x11
+	.ascii "<<<<<<<<"
+
+	.ascii ">>>>"
+	.secidx ext24
+	.byte 0x11
+	.secidx ext2d
+	.byte 0x11
+	.secidx ext36
+	.byte 0x11
+	.secidx ext3f
+	.byte 0x11
+	.ascii "<<<<<<<<"
+
+.section .rdata
+
+	.ascii ">>>>"
+nex04:	.ascii "<<<<"
+	.ascii ">>>>>"
+nex0d:	.ascii "<<<"
+	.ascii ">>>>>>"
+nex16:	.ascii "<<"
+	.ascii ">>>>>>>"
+nex1f:	.ascii "<"
+	.ascii ">>>>"
+
+	.p2align 4,0