RISC-V: Support B, Zaamo and Zalrsc extensions.

* https://github.com/riscv/riscv-b/tags
Added standard B extension back, which implies Zba, Zbb and Zbs extensions.

* https://github.com/riscv/riscv-zaamo-zalrsc/tags
Splited standard A extension into two new extensions, Zaamo and Zalrsc.
The A extension implies Zaamo and Zalrsc extensions.

Not sure if we need to do the similar check as i and zicsr/zifencei.

Passed riscv[32|64]-[elf/linux] binutils testcases.

bfd/
	* elfxx-riscv.c (riscv_implicit_subsets): Added imply rules
	for A and B extensions.  The A implies Zaamo and Zalrsc, the
	B implies Zba, Zbb and Zbs.
	(riscv_supported_std_ext): Supported B extension with v1.0.
	(riscv_supported_std_z_ext): Supported Zaamo and Zalrsc with v1.0.
	(riscv_multi_subset_supports, riscv_multi_subset_supports_ext): Updated.
include/
	* opcode/riscv.h (riscv_insn_class): Removed INSN_CLASS_A, Added
	INSN_CLASS_ZAAMO and INSN_CLASS_ZALRSC.
opcodes/
	* riscv-opc.c (riscv_opcodes): Splited standard A extension into two
	new extensions, Zaamo and Zalrsc.
gas/
	* testsuite/gas/riscv/march-imply-a.d: New testcase.
	* testsuite/gas/riscv/march-imply-b.d: New testcase.
	* testsuite/gas/riscv/attribute-01.d: Updated.
	* testsuite/gas/riscv/attribute-02.d: Updated.
	* testsuite/gas/riscv/attribute-03.d: Updated.
	* testsuite/gas/riscv/attribute-04.d: Updated.
	* testsuite/gas/riscv/attribute-05.d: Updated.
	* testsuite/gas/riscv/attribute-10.d: Updated.
	* testsuite/gas/riscv/mapping-symbols.d: Updated.
	* testsuite/gas/riscv/march-imply-g.d: Updated.
	* testsuite/gas/riscv/march-imply-unsupported.d: Updated.
	* testsuite/gas/riscv/march-ok-reorder.d: Updated.
ld/
	* testsuite/ld-riscv-elf/attr-merge-arch-01.d: Updated.
	* testsuite/ld-riscv-elf/attr-merge-arch-02.d: Updated.
	* testsuite/ld-riscv-elf/attr-merge-arch-03.d: Updated.
	* testsuite/ld-riscv-elf/attr-merge-user-ext-01.d: Updated.

1 files changed, 16 insertions, 4 deletions

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index b08e445..dfacb87 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1277,6 +1277,11 @@ static struct riscv_implicit_subset riscv_implicit_subsets[] =
   {"ssstateen", "zicsr",	check_implicit_always},
   {"sstc", "zicsr",		check_implicit_always},
   {"svadu", "zicsr",		check_implicit_always},
+  {"b", "zba",		check_implicit_always},
+  {"b", "zbb",		check_implicit_always},
+  {"b", "zbs",		check_implicit_always},
+  {"a", "zaamo",	check_implicit_always},
+  {"a", "zalrsc",	check_implicit_always},
 
   {"xsfvcp", "zve32x",  check_implicit_always},
   {NULL, NULL, NULL}
@@ -1329,6 +1334,7 @@ static struct riscv_supported_ext riscv_supported_std_ext[] =
   {"c",		ISA_SPEC_CLASS_20191213,	2, 0, 0 },
   {"c",		ISA_SPEC_CLASS_20190608,	2, 0, 0 },
   {"c",		ISA_SPEC_CLASS_2P2,		2, 0, 0 },
+  {"b",		ISA_SPEC_CLASS_DRAFT,		1, 0, 0 },
   {"v",		ISA_SPEC_CLASS_DRAFT,		1, 0, 0 },
   {"h",		ISA_SPEC_CLASS_DRAFT,		1, 0, 0 },
   {NULL, 0, 0, 0, 0}
@@ -1349,7 +1355,9 @@ static struct riscv_supported_ext riscv_supported_std_z_ext[] =
   {"zihintpause",	ISA_SPEC_CLASS_DRAFT,		2, 0,  0 },
   {"zihpm",		ISA_SPEC_CLASS_DRAFT,		2, 0,  0 },
   {"zmmul",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  {"zaamo",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zabha",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  {"zalrsc",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zawrs",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zfa",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zfh",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
@@ -2519,10 +2527,12 @@ riscv_multi_subset_supports (riscv_parse_subset_t *rps,
       return riscv_subset_supports (rps, "m");
     case INSN_CLASS_ZMMUL:
       return riscv_subset_supports (rps, "zmmul");
-    case INSN_CLASS_A:
-      return riscv_subset_supports (rps, "a");
+    case INSN_CLASS_ZAAMO:
+      return riscv_subset_supports (rps, "zaamo");
     case INSN_CLASS_ZABHA:
       return riscv_subset_supports (rps, "zabha");
+    case INSN_CLASS_ZALRSC:
+      return riscv_subset_supports (rps, "zalrsc");
     case INSN_CLASS_ZAWRS:
       return riscv_subset_supports (rps, "zawrs");
     case INSN_CLASS_F:
@@ -2745,10 +2755,12 @@ riscv_multi_subset_supports_ext (riscv_parse_subset_t *rps,
       return "m";
     case INSN_CLASS_ZMMUL:
       return _ ("m' or `zmmul");
-    case INSN_CLASS_A:
-      return "a";
+    case INSN_CLASS_ZAAMO:
+      return "zaamo";
     case INSN_CLASS_ZABHA:
       return "zabha";
+    case INSN_CLASS_ZALRSC:
+      return "zalrsc";
     case INSN_CLASS_ZAWRS:
       return "zawrs";
     case INSN_CLASS_F: