binutils: rework jump pseudoisntruction

"jump" was renamed to "tail" (as in tail call) and may freely clobber a
t-register, as before.  A new "jump" was added that requires a second
argument, which is the scratch register it may clobber.

"tail" should be used for tail calls; "jump" should be used for
intraprocedural jumps more than 1 MiB away.

binutils/gas/config/tc-riscv.c

@@ -935,13 +935,10 @@ load_const (int reg, expressionS *ep)
 static void
 macro (struct riscv_cl_insn *ip)
 {
-  unsigned int rd, rs1, rs2;
-  int mask;
-
-  rd = (ip->insn_opcode >> OP_SH_RD) & OP_MASK_RD;
-  rs1 = (ip->insn_opcode >> OP_SH_RS1) & OP_MASK_RS1;
-  rs2 = (ip->insn_opcode >> OP_SH_RS2) & OP_MASK_RS2;
-  mask = ip->insn_mo->mask;
+  int rd = (ip->insn_opcode >> OP_SH_RD) & OP_MASK_RD;
+  int rs1 = (ip->insn_opcode >> OP_SH_RS1) & OP_MASK_RS1;
+  int rs2 = (ip->insn_opcode >> OP_SH_RS2) & OP_MASK_RS2;
+  int mask = ip->insn_mo->mask;
 
   switch (mask)
     {
@@ -1055,13 +1052,7 @@ macro (struct riscv_cl_insn *ip)
 		    BFD_RELOC_RISCV_PCREL_HI20, BFD_RELOC_RISCV_PCREL_LO12_S);
       break;
 
-    case M_JUMP:
-      rd = 0;
-      goto do_call;
     case M_CALL:
-      rd = X_RA;
-do_call:
-      rs1 = reg_lookup_assert ("t0", RCLASS_GPR);
       riscv_call (rd, rs1, &offset_expr, offset_reloc);
       break;
 

binutils/include/opcode/riscv.h

@@ -297,7 +297,6 @@ enum
   M_FSW,
   M_FSD,
   M_CALL,
-  M_JUMP,
   M_J,
   M_LI,
   M_VF,

binutils/opcodes/riscv-opc.c

@@ -175,8 +175,9 @@ const struct riscv_opcode riscv_builtin_opcodes[] =
 {"j",         "I",   "a",  MATCH_JAL, MASK_JAL | MASK_RD, match_opcode,   INSN_ALIAS },
 {"jal",       "I",   "a",  MATCH_JAL | (X_RA << OP_SH_RD), MASK_JAL | MASK_RD, match_opcode,   INSN_ALIAS|WR_xd },
 {"jal",       "I",   "d,a",  MATCH_JAL, MASK_JAL, match_opcode,   WR_xd },
-{"call",      "I",   "c",  0,    (int) M_CALL,  match_never, INSN_MACRO },
-{"jump",      "I",   "c",  0,    (int) M_JUMP,  match_never, INSN_MACRO },
+{"call",      "I",   "c", (X_T0 << OP_SH_RS1) | (X_RA << OP_SH_RD), (int) M_CALL,  match_never, INSN_MACRO },
+{"tail",      "I",   "c", (X_T0 << OP_SH_RS1), (int) M_CALL,  match_never, INSN_MACRO },
+{"jump",      "I",   "c,s", 0, (int) M_CALL,  match_never, INSN_MACRO },
 {"jr",        "I",   "s",  MATCH_JALR, MASK_JALR | MASK_RD | MASK_IMM, match_opcode,   INSN_ALIAS|WR_xd|RD_xs1 },
 {"jr",        "I",   "s,j",  MATCH_JALR, MASK_JALR | MASK_RD, match_opcode,   INSN_ALIAS|WR_xd|RD_xs1 },
 {"jalr",      "I",   "s",  MATCH_JALR | (X_RA << OP_SH_RD), MASK_JALR | MASK_RD | MASK_IMM, match_opcode,   INSN_ALIAS|WR_xd|RD_xs1 },

gcc/gcc/config/riscv/riscv.md

@@ -2286,8 +2286,8 @@
 	 (match_operand 1 "" ""))]
   "SIBLING_CALL_P (insn)"
   { return REG_P (operands[0]) ? "jr\t%0"
-	   : absolute_symbolic_operand (operands[0], VOIDmode) ? "jump\t%0"
-	   : "jump\t%0@"; }
+	   : absolute_symbolic_operand (operands[0], VOIDmode) ? "tail\t%0"
+	   : "tail\t%0@"; }
   [(set_attr "type" "call")])
 
 (define_expand "sibcall_value"
@@ -2307,8 +2307,8 @@
               (match_operand 2 "" "")))]
   "SIBLING_CALL_P (insn)"
   { return REG_P (operands[1]) ? "jr\t%1"
-	   : absolute_symbolic_operand (operands[1], VOIDmode) ? "jump\t%1"
-	   : "jump\t%1@"; }
+	   : absolute_symbolic_operand (operands[1], VOIDmode) ? "tail\t%1"
+	   : "tail\t%1@"; }
   [(set_attr "type" "call")])
 
 (define_insn "sibcall_value_multiple_internal"
@@ -2321,8 +2321,8 @@
    (clobber (match_scratch:SI 4 "=j,j"))]
   "SIBLING_CALL_P (insn)"
   { return REG_P (operands[1]) ? "jr\t%1"
-	   : absolute_symbolic_operand (operands[1], VOIDmode) ? "jump\t%1"
-	   : "jump\t%1@"; }
+	   : absolute_symbolic_operand (operands[1], VOIDmode) ? "tail\t%1"
+	   : "tail\t%1@"; }
   [(set_attr "type" "call")])
 
 (define_expand "call"

glibc/sysdeps/riscv/start.S

@@ -55,7 +55,7 @@ ENTRY(ENTRY_POINT)
 	lla   a4, __libc_csu_fini
 	move  a6, sp  /* stack_end */
 	
-	jump  __libc_start_main@
+	tail  __libc_start_main@
 END(ENTRY_POINT)
 
 /* Define a symbol for the first piece of initialized data.  */

newlib/libgloss/riscv/crt0.S

@@ -28,7 +28,7 @@ _start:
   addi    a1, sp, _RISCV_SZPTR/8  # a1 = argv
   li      a2, 0                   # a2 = envp = NULL
   call    main
-  jump    exit
+  tail    exit
 
   .global _init
   .global _fini