RISC-V: Print highest address (-1) on the disassembler

This patch makes possible to print the highest address (-1) and the addresses
related to gp which value is -1.  This is particularly useful if the highest
address space is used for I/O registers and corresponding symbols are defined.
Besides, despite that it is very rare to have GP the highest address, it would
be nice because we enabled highest address printing on regular cases.

gas/ChangeLog:

	* testsuite/gas/riscv/dis-addr-topaddr.s: New test for the top
	address (-1) printing.
	* testsuite/gas/riscv/dis-addr-topaddr-32.d: Likewise.
	* testsuite/gas/riscv/dis-addr-topaddr-64.d: Likewise.
	* testsuite/gas/riscv/dis-addr-topaddr-gp.s: New test for
	GP-relative addressing when GP is the highest address (-1).
	* testsuite/gas/riscv/dis-addr-topaddr-gp-32.d: Likewise.
	* testsuite/gas/riscv/dis-addr-topaddr-gp-64.d: Likewise.

opcodes/ChangeLog:

	* riscv-dis.c (struct riscv_private_data): Add `to_print_addr' to
	enable printing the highest address.
	(maybe_print_address): Utilize `to_print_addr'.
	(riscv_disassemble_insn): Likewise.

6 files changed, 71 insertions, 0 deletions

diff --git a/gas/testsuite/gas/riscv/dis-addr-topaddr-32.d b/gas/testsuite/gas/riscv/dis-addr-topaddr-32.d
new file mode 100644
index 0000000..87854cd
--- /dev/null
+++ b/gas/testsuite/gas/riscv/dis-addr-topaddr-32.d
@@ -0,0 +1,11 @@
+#as: -march=rv32ic
+#source: dis-addr-topaddr.s
+#objdump: -d
+
+.*:     file format elf32-(little|big)riscv
+
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+[0-9a-f]+:[ 	]+fff00283[ 	]+lb[   	]+t0,-1\(zero\) # ffffffff <addr_top>
diff --git a/gas/testsuite/gas/riscv/dis-addr-topaddr-64.d b/gas/testsuite/gas/riscv/dis-addr-topaddr-64.d
new file mode 100644
index 0000000..38f67ef
--- /dev/null
+++ b/gas/testsuite/gas/riscv/dis-addr-topaddr-64.d
@@ -0,0 +1,11 @@
+#as: -march=rv64ic -defsym rv64=1
+#source: dis-addr-topaddr.s
+#objdump: -d
+
+.*:     file format elf64-(little|big)riscv
+
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+[0-9a-f]+:[ 	]+fff00283[ 	]+lb[   	]+t0,-1\(zero\) # ffffffffffffffff <addr_top>
diff --git a/gas/testsuite/gas/riscv/dis-addr-topaddr-gp-32.d b/gas/testsuite/gas/riscv/dis-addr-topaddr-gp-32.d
new file mode 100644
index 0000000..875bfe7
--- /dev/null
+++ b/gas/testsuite/gas/riscv/dis-addr-topaddr-gp-32.d
@@ -0,0 +1,12 @@
+#as: -march=rv32i
+#source: dis-addr-topaddr-gp.s
+#objdump: -d
+
+.*:     file format elf32-(little|big)riscv
+
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+[0-9a-f]+:[ 	]+0051a283[ 	]+lw[   	]+t0,5\(gp\) # 4 <addr_rel_gp_pos>
+[ 	]+[0-9a-f]+:[ 	]+ffd1a303[ 	]+lw[   	]+t1,-3\(gp\) # fffffffc <addr_rel_gp_neg>
diff --git a/gas/testsuite/gas/riscv/dis-addr-topaddr-gp-64.d b/gas/testsuite/gas/riscv/dis-addr-topaddr-gp-64.d
new file mode 100644
index 0000000..5ac4b52
--- /dev/null
+++ b/gas/testsuite/gas/riscv/dis-addr-topaddr-gp-64.d
@@ -0,0 +1,12 @@
+#as: -march=rv64i -defsym rv64=1
+#source: dis-addr-topaddr-gp.s
+#objdump: -d
+
+.*:     file format elf64-(little|big)riscv
+
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+[0-9a-f]+:[ 	]+0051a283[ 	]+lw[   	]+t0,5\(gp\) # 4 <addr_rel_gp_pos>
+[ 	]+[0-9a-f]+:[ 	]+ffd1a303[ 	]+lw[   	]+t1,-3\(gp\) # fffffffffffffffc <addr_rel_gp_neg>
diff --git a/gas/testsuite/gas/riscv/dis-addr-topaddr-gp.s b/gas/testsuite/gas/riscv/dis-addr-topaddr-gp.s
new file mode 100644
index 0000000..6ba9fc7
--- /dev/null
+++ b/gas/testsuite/gas/riscv/dis-addr-topaddr-gp.s
@@ -0,0 +1,15 @@
+.ifdef rv64
+topbase = 0xffffffff00000000
+.else
+topbase = 0
+.endif
+
+.set __global_pointer$, topbase + 0xffffffff  # -1
+.set addr_rel_gp_pos,             0x00000004  # +4
+.set addr_rel_gp_neg,   topbase + 0xfffffffc  # -4
+
+target:
+	# Use addresses relative to gp
+	# (gp is the highest address)
+	lw	t0, +5(gp)
+	lw	t1, -3(gp)
diff --git a/gas/testsuite/gas/riscv/dis-addr-topaddr.s b/gas/testsuite/gas/riscv/dis-addr-topaddr.s
new file mode 100644
index 0000000..b66587f
--- /dev/null
+++ b/gas/testsuite/gas/riscv/dis-addr-topaddr.s
@@ -0,0 +1,10 @@
+.ifdef rv64
+topbase = 0xffffffff00000000
+.else
+topbase = 0
+.endif
+
+.set addr_top, topbase + 0xffffffff  # -1
+
+target:
+	lb	t0, -1(zero)