[PATCH v2 3/5] RISC-V: Add assembly support for TLSDESC.

[Tatsuyuki Ishi <ishitatsuyuki@gmail.com>]

gas/
    * tc-riscv.c (percent_op_*): Add support for %tlsdesc_hi,
    %tlsdesc_load_lo, %tlsdesc_add_lo and %tlsdesc_call. percent_op_rtype
    renamed to percent_op_relax_only as this matcher is extended to handle
    jalr as well which is not R-type.
    (riscv_ip): Apply the percent_op_relax_only rename and update comment.
    (md_apply_fix): Add TLSDESC_* to relaxable list. Add TLSDESC_HI20 to
    TLS relocation check list.
    * testsuite/gas/riscv/tlsdesc.*: New test cases for TLSDESC relocation
    generation.
opcodes/
    * riscv-opc.c (riscv_opcodes): Add a new syntax for jalr with
    %tlsdesc_call annotations.
---
 gas/config/tc-riscv.c             | 18 +++++++++++++-----
 gas/testsuite/gas/riscv/tlsdesc.d | 22 ++++++++++++++++++++++
 gas/testsuite/gas/riscv/tlsdesc.s | 24 ++++++++++++++++++++++++
 opcodes/riscv-opc.c               |  1 +
 4 files changed, 60 insertions(+), 5 deletions(-)
 create mode 100644 gas/testsuite/gas/riscv/tlsdesc.d
 create mode 100644 gas/testsuite/gas/riscv/tlsdesc.s

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index 959cbbc32a5..0a1fac9de9d 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -2195,6 +2195,7 @@ static const struct percent_op_match percent_op_utype[] =
   {"tprel_hi", BFD_RELOC_RISCV_TPREL_HI20},
   {"pcrel_hi", BFD_RELOC_RISCV_PCREL_HI20},
   {"got_pcrel_hi", BFD_RELOC_RISCV_GOT_HI20},
+  {"tlsdesc_hi", BFD_RELOC_RISCV_TLSDESC_HI20},
   {"tls_ie_pcrel_hi", BFD_RELOC_RISCV_TLS_GOT_HI20},
   {"tls_gd_pcrel_hi", BFD_RELOC_RISCV_TLS_GD_HI20},
   {"hi", BFD_RELOC_RISCV_HI20},
@@ -2206,6 +2207,8 @@ static const struct percent_op_match percent_op_itype[] =
   {"lo", BFD_RELOC_RISCV_LO12_I},
   {"tprel_lo", BFD_RELOC_RISCV_TPREL_LO12_I},
   {"pcrel_lo", BFD_RELOC_RISCV_PCREL_LO12_I},
+  {"tlsdesc_load_lo", BFD_RELOC_RISCV_TLSDESC_LOAD_LO12},
+  {"tlsdesc_add_lo", BFD_RELOC_RISCV_TLSDESC_ADD_LO12},
   {0, 0}
 };
 
@@ -2217,8 +2220,9 @@ static const struct percent_op_match percent_op_stype[] =
   {0, 0}
 };
 
-static const struct percent_op_match percent_op_rtype[] =
+static const struct percent_op_match percent_op_relax_only[] =
 {
+  {"tlsdesc_call", BFD_RELOC_RISCV_TLSDESC_CALL},
   {"tprel_add", BFD_RELOC_RISCV_TPREL_ADD},
   {0, 0}
 };
@@ -3326,10 +3330,10 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	      *imm_reloc = BFD_RELOC_RISCV_LO12_I;
 	      goto load_store;
 	    case '1':
-	      /* This is used for TLS, where the fourth operand is
-		 %tprel_add, to get a relocation applied to an add
-		 instruction, for relaxation to use.  */
-	      p = percent_op_rtype;
+	      /* This is used for TLS relocations that acts as relaxation
+	         markers and do not change the instruction encoding,
+	         i.e. %tprel_add and %tlsdesc_call.  */
+	      p = percent_op_relax_only;
 	      goto alu_op;
 	    case '0': /* AMO displacement, which must be zero.  */
 	    load_store:
@@ -4082,6 +4086,7 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
     case BFD_RELOC_RISCV_TPREL_LO12_I:
     case BFD_RELOC_RISCV_TPREL_LO12_S:
     case BFD_RELOC_RISCV_TPREL_ADD:
+    case BFD_RELOC_RISCV_TLSDESC_HI20:
       relaxable = true;
       /* Fall through.  */
 
@@ -4255,6 +4260,9 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
 
     case BFD_RELOC_RISCV_CALL:
     case BFD_RELOC_RISCV_CALL_PLT:
+    case BFD_RELOC_RISCV_TLSDESC_LOAD_LO12:
+    case BFD_RELOC_RISCV_TLSDESC_ADD_LO12:
+    case BFD_RELOC_RISCV_TLSDESC_CALL:
       relaxable = true;
       break;
 
diff --git a/gas/testsuite/gas/riscv/tlsdesc.d b/gas/testsuite/gas/riscv/tlsdesc.d
new file mode 100644
index 00000000000..8ba35826130
--- /dev/null
+++ b/gas/testsuite/gas/riscv/tlsdesc.d
@@ -0,0 +1,22 @@
+#as: -march=rv32ia
+#source: tlsdesc.s
+#readelf: -Wr
+
+Relocation section '.rela.text' at offset 0x[0-9a-f]+ contains 16 entries:
+ +Offset +Info +Type +Sym. Value +Symbol's Name \+ Addend
+0+ +0+a3e +R_RISCV_TLSDESC_HI20 +0+ +sg1 \+ 0
+0+ +0+33 +R_RISCV_RELAX + 0
+0+4 +0+63f +R_RISCV_TLSDESC_LOAD_LO12 0+ +\.desc1 \+ 0
+0+4 +0+33 +R_RISCV_RELAX + 0
+0+8 +0+640 +R_RISCV_TLSDESC_ADD_LO12 0+ +\.desc1 \+ 0
+0+8 +0+33 +R_RISCV_RELAX + 0
+0+c +0+641 +R_RISCV_TLSDESC_CALL +0+ +\.desc1 \+ 0
+0+c +0+33 +R_RISCV_RELAX + 0
+0+10 +0+53e +R_RISCV_TLSDESC_HI20 +0+4 +sl1 \+ 0
+0+10 +0+33 +R_RISCV_RELAX + 0
+0+14 +0+83f +R_RISCV_TLSDESC_LOAD_LO12 0+10 +\.desc2 \+ 0
+0+14 +0+33 +R_RISCV_RELAX + 0
+0+18 +0+840 +R_RISCV_TLSDESC_ADD_LO12 0+10 +\.desc2 \+ 0
+0+18 +0+33 +R_RISCV_RELAX +0
+0+1c +0+841 +R_RISCV_TLSDESC_CALL +0+10 +\.desc2 \+ 0
+0+1c +0+33 +R_RISCV_RELAX +0
\ No newline at end of file
diff --git a/gas/testsuite/gas/riscv/tlsdesc.s b/gas/testsuite/gas/riscv/tlsdesc.s
new file mode 100644
index 00000000000..15468d5f947
--- /dev/null
+++ b/gas/testsuite/gas/riscv/tlsdesc.s
@@ -0,0 +1,24 @@
+	.section	.tbss,"awT",@nobits
+	.global sg1
+sg1:
+	.zero	4
+sl1:
+	.zero	4
+
+	.text
+	.globl	_start
+	.type	_start,@function
+_start:
+.desc1:
+	auipc	a0, %tlsdesc_hi(sg1)
+	lw	t0, %tlsdesc_load_lo(.desc1)(a0)
+	addi	a0, a0, %tlsdesc_add_lo(.desc1)
+	jalr	t0, t0, %tlsdesc_call(.desc1)
+
+.desc2:
+	auipc	a0, %tlsdesc_hi(sl1)
+	lw	t0, %tlsdesc_load_lo(.desc2)(a0)
+	addi	a0, a0, %tlsdesc_add_lo(.desc2)
+	jalr	t0, t0, %tlsdesc_call(.desc2)
+
+	ret
diff --git a/opcodes/riscv-opc.c b/opcodes/riscv-opc.c
index 067e9fdb611..467666b9805 100644
--- a/opcodes/riscv-opc.c
+++ b/opcodes/riscv-opc.c
@@ -370,6 +370,7 @@ const struct riscv_opcode riscv_opcodes[] =
 {"jalr",        0, INSN_CLASS_I, "s,j",       MATCH_JALR|(X_RA << OP_SH_RD), MASK_JALR|MASK_RD, match_opcode, INSN_ALIAS|INSN_JSR },
 {"jalr",        0, INSN_CLASS_I, "d,s",       MATCH_JALR, MASK_JALR|MASK_IMM, match_opcode, INSN_ALIAS|INSN_JSR },
 {"jalr",        0, INSN_CLASS_I, "d,o(s)",    MATCH_JALR, MASK_JALR, match_opcode, INSN_JSR },
+{"jalr",        0, INSN_CLASS_I, "d,s,1",     MATCH_JALR, MASK_JALR|MASK_IMM, match_opcode, INSN_JSR },
 {"jalr",        0, INSN_CLASS_I, "d,s,j",     MATCH_JALR, MASK_JALR, match_opcode, INSN_JSR },
 {"j",           0, INSN_CLASS_C, "Ca",        MATCH_C_J, MASK_C_J, match_opcode, INSN_ALIAS|INSN_BRANCH },
 {"j",           0, INSN_CLASS_I, "a",         MATCH_JAL, MASK_JAL|MASK_RD, match_opcode, INSN_ALIAS|INSN_BRANCH },
-- 
2.42.0