RISC-V: Support to parse the multi-letter prefix in the architecture string.

The original discussion is as follows,
https://github.com/riscv/riscv-isa-manual/issues/637

I never considered the prefixes may have multiple letters, like zxm.
But the ISA spec has been updated for a long time that I haven't noticed.
This patch rewrites the part of architecture parser to support parsing
the multi-letter prefixes.  Besides, I also improve the parser to report
errors in details.  One of the most obvious improvement is - Do not parse
the prefixed extensions according to the orders in the parse_config.
If we do so, then we used to get "unexpected ISA string at end" errors,
but the message is a little bit  hard to know what is happening.  I Remove
the confused message, and let riscv_parse_prefixed_ext to report the details.

bfd/
    * elfxx-riscv.c (riscv_std_z_ext_strtab): Moved forward.
    (riscv_std_s_ext_strtab): Likewise.
    (riscv_std_h_ext_strtab): Likewise.
    (riscv_std_zxm_ext_strtab): Added for the zxm prefix.
    (enum riscv_prefix_ext_class): Moved forward and renamed from
    riscv_isa_ext_class.  Reorder them according to the parsing order,
    since the enum values are used to check the orders in the
    riscv_compare_subsets.
    (struct riscv_parse_prefix_config): Moved forward and renamed from
    riscv_parse_config_t.  Also removed the ext_valid_p field, the
    related functions are replaced by riscv_valid_prefixed_ext.
    (parse_config): Moved forward and updated.  The more letters of the
    prefix string, the more forward it must be defined.  Otherwise, we
    will get the wrong mapping when using strncmp in riscv_get_prefix_class.
    (riscv_get_prefix_class): Moved forward.  Support to parse the
    multi-letter prefix, like zxm.
    (riscv_known_prefixed_ext): New function, check if the prefixed
    extension is supported according to the right riscv_std_*_ext_strtab.
    (riscv_valid_prefixed_ext): New function, used to replace the
    riscv_ext_*_valid_p functions.
    (riscv_init_ext_order): Do not set the values for prefix keywords
    since they may have multiple letters for now.
    (riscv_compare_subsets): Set the order values of prefix keywords
    to negative numbers according to the riscv_prefix_ext_class.
    (riscv_parse_std_ext): Call riscv_get_prefix_class to see if we
    have parsed the prefixed extensions.
    (riscv_parse_prefixed_ext): Updated and removed the parameter config.
    Report error when the prefix is unknown.
    (riscv_parse_subset): Do not parse the prefixed extensions according
    to the orders in the parse_config.  Remove the confused message and
    let riscv_parse_prefixed_ext to report the details.
    * elfxx-riscv.h (enum riscv_isa_ext_class): Moved to elfxx-riscv.c.
    (riscv_get_prefix_class): Removed to static.
gas/
    * testsuite/gas/riscv/march-fail-order-x-std.d: Renamed from
    march-fail-porder-x-std.d.
    * testsuite/gas/riscv/march-fail-order-z-std.d: Renamed from
    march-fail-porder-z-std.d.
    * testsuite/gas/riscv/march-fail-order-x-z.d: Renamed from
    march-fail-porder-x-z.d.
    * testsuite/gas/riscv/march-fail-order-zx-std.l: Added to replace
    march-fail-porder.l.
    * testsuite/gas/riscv/march-fail-order-x-z.l: Likewise.
    * testsuite/gas/riscv/march-fail-order-x.l: Updated.
    * testsuite/gas/riscv/march-fail-order-z.l: Likewise.
    * testsuite/gas/riscv/march-fail-single-prefix-h.d: Renamed from
    march-fail-single-char-h.d.
    * testsuite/gas/riscv/march-fail-single-prefix-s.d: Renamed from
    march-fail-single-char-s.d.
    * testsuite/gas/riscv/march-fail-single-prefix-x.d: Renamed from
    march-fail-single-char-x.d.
    * testsuite/gas/riscv/march-fail-single-prefix-z.d: Renamed from
    march-fail-single-char-z.d.
    * testsuite/gas/riscv/march-fail-single-prefix-zmx.d: Added.
    * testsuite/gas/riscv/march-fail-single-prefix.l: Added to replace
    march-fail-single-prefix.l.
    * testsuite/gas/riscv/march-fail-unknown-zxm.d: Added.
    * testsuite/gas/riscv/march-fail-unknown-std.l: Updated.
    * testsuite/gas/riscv/march-fail-unknown.l: Likewise.

23 files changed, 59 insertions, 23 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 13e4272..15e4c07 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,31 @@
+2021-04-12  Nelson Chu  <nelson.chu@sifive.com>
+
+	* testsuite/gas/riscv/march-fail-order-x-std.d: Renamed from
+	march-fail-porder-x-std.d.
+	* testsuite/gas/riscv/march-fail-order-z-std.d: Renamed from
+	march-fail-porder-z-std.d.
+	* testsuite/gas/riscv/march-fail-order-x-z.d: Renamed from
+	march-fail-porder-x-z.d.
+	* testsuite/gas/riscv/march-fail-order-zx-std.l: Added to replace
+	march-fail-porder.l.
+	* testsuite/gas/riscv/march-fail-order-x-z.l: Likewise.
+	* testsuite/gas/riscv/march-fail-order-x.l: Updated.
+	* testsuite/gas/riscv/march-fail-order-z.l: Likewise.
+	* testsuite/gas/riscv/march-fail-single-prefix-h.d: Renamed from
+	march-fail-single-char-h.d.
+	* testsuite/gas/riscv/march-fail-single-prefix-s.d: Renamed from
+	march-fail-single-char-s.d.
+	* testsuite/gas/riscv/march-fail-single-prefix-x.d: Renamed from
+	march-fail-single-char-x.d.
+	* testsuite/gas/riscv/march-fail-single-prefix-z.d: Renamed from
+	march-fail-single-char-z.d.
+	* testsuite/gas/riscv/march-fail-single-prefix-zmx.d: Added.
+	* testsuite/gas/riscv/march-fail-single-prefix.l: Added to replace
+	march-fail-single-prefix.l.
+	* testsuite/gas/riscv/march-fail-unknown-zxm.d: Added.
+	* testsuite/gas/riscv/march-fail-unknown-std.l: Updated.
+	* testsuite/gas/riscv/march-fail-unknown.l: Likewise.
+
 2021-04-09  Tejas Belagod  <tejas.belagod@arm.com>
 
 	* config/tc-aarch64.c (warn_unpredictable_ldst): Clean-up diagnostic messages
diff --git a/gas/testsuite/gas/riscv/march-fail-porder-x-std.d b/gas/testsuite/gas/riscv/march-fail-order-x-std.d
index 2bef073..4762f3d 100644
--- a/gas/testsuite/gas/riscv/march-fail-porder-x-std.d
+++ b/gas/testsuite/gas/riscv/march-fail-order-x-std.d
@@ -1,3 +1,3 @@
 #as: -march=rv32i_xargle2p0_mafd
 #source: empty.s
-#error_output: march-fail-porder.l
+#error_output: march-fail-order-zx-std.l
diff --git a/gas/testsuite/gas/riscv/march-fail-porder-x-z.d b/gas/testsuite/gas/riscv/march-fail-order-x-z.d
index 094180d..7245e68 100644
--- a/gas/testsuite/gas/riscv/march-fail-porder-x-z.d
+++ b/gas/testsuite/gas/riscv/march-fail-order-x-z.d
@@ -1,3 +1,3 @@
 #as: -march=rv32i_xargle2p0_zicsr2p0
 #source: empty.s
-#error_output: march-fail-porder.l
+#error_output: march-fail-order-x-z.l
diff --git a/gas/testsuite/gas/riscv/march-fail-order-x-z.l b/gas/testsuite/gas/riscv/march-fail-order-x-z.l
new file mode 100644
index 0000000..53ea820
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-order-x-z.l
@@ -0,0 +1,2 @@
+.*Assembler messages:
+.*Error: .*prefixed ISA extension `zicsr' is not in expected order.  It must come before `xargle'
diff --git a/gas/testsuite/gas/riscv/march-fail-order-x.l b/gas/testsuite/gas/riscv/march-fail-order-x.l
index 025db14..cfb1185 100644
--- a/gas/testsuite/gas/riscv/march-fail-order-x.l
+++ b/gas/testsuite/gas/riscv/march-fail-order-x.l
@@ -1,2 +1,2 @@
 .*Assembler messages:
-.*Error: .*x ISA extension `xargle' is not in alphabetical order.  It must come before `xbargle'
+.*Error: .*prefixed ISA extension `xargle' is not in expected order.  It must come before `xbargle'
diff --git a/gas/testsuite/gas/riscv/march-fail-porder-z-std.d b/gas/testsuite/gas/riscv/march-fail-order-z-std.d
index 1fa1a15..42526de 100644
--- a/gas/testsuite/gas/riscv/march-fail-porder-z-std.d
+++ b/gas/testsuite/gas/riscv/march-fail-order-z-std.d
@@ -1,3 +1,3 @@
 #as: -march=rv32i_zicsr2p0_mafd
 #source: empty.s
-#error_output: march-fail-porder.l
+#error_output: march-fail-order-zx-std.l
diff --git a/gas/testsuite/gas/riscv/march-fail-order-z.l b/gas/testsuite/gas/riscv/march-fail-order-z.l
index a98c53a..468c412 100644
--- a/gas/testsuite/gas/riscv/march-fail-order-z.l
+++ b/gas/testsuite/gas/riscv/march-fail-order-z.l
@@ -1,2 +1,2 @@
 .*Assembler messages:
-.*Error: .*z ISA extension `zicsr' is not in alphabetical order.  It must come before `zifencei'
+.*Error: .*prefixed ISA extension `zicsr' is not in expected order.  It must come before `zifencei'
diff --git a/gas/testsuite/gas/riscv/march-fail-order-zx-std.l b/gas/testsuite/gas/riscv/march-fail-order-zx-std.l
new file mode 100644
index 0000000..4f6b98c
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-order-zx-std.l
@@ -0,0 +1,2 @@
+.*Assembler messages:
+.*Error: .*unknown prefix class for the ISA extension `mafd'
diff --git a/gas/testsuite/gas/riscv/march-fail-porder.l b/gas/testsuite/gas/riscv/march-fail-porder.l
deleted file mode 100644
index c5496ea..0000000
--- a/gas/testsuite/gas/riscv/march-fail-porder.l
+++ /dev/null
@@ -1,2 +0,0 @@
-.*Assembler messages:
-.*Error: .*unexpected ISA string at end:.*
diff --git a/gas/testsuite/gas/riscv/march-fail-single-char-h.d b/gas/testsuite/gas/riscv/march-fail-single-char-h.d
deleted file mode 100644
index 7fca957..0000000
--- a/gas/testsuite/gas/riscv/march-fail-single-char-h.d
+++ /dev/null
@@ -1,3 +0,0 @@
-#as: -march=rv32ih
-#source: empty.s
-#error_output: march-fail-single-char.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-char-s.d b/gas/testsuite/gas/riscv/march-fail-single-char-s.d
deleted file mode 100644
index b3aace9..0000000
--- a/gas/testsuite/gas/riscv/march-fail-single-char-s.d
+++ /dev/null
@@ -1,3 +0,0 @@
-#as: -march=rv32is
-#source: empty.s
-#error_output: march-fail-single-char.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-char-x.d b/gas/testsuite/gas/riscv/march-fail-single-char-x.d
deleted file mode 100644
index 585608c..0000000
--- a/gas/testsuite/gas/riscv/march-fail-single-char-x.d
+++ /dev/null
@@ -1,3 +0,0 @@
-#as: -march=rv32ix
-#source: empty.s
-#error_output: march-fail-single-char.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-char-z.d b/gas/testsuite/gas/riscv/march-fail-single-char-z.d
deleted file mode 100644
index daf96d2..0000000
--- a/gas/testsuite/gas/riscv/march-fail-single-char-z.d
+++ /dev/null
@@ -1,3 +0,0 @@
-#as: -march=rv32iz
-#source: empty.s
-#error_output: march-fail-single-char.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-char.l b/gas/testsuite/gas/riscv/march-fail-single-char.l
deleted file mode 100644
index 435d0b2..0000000
--- a/gas/testsuite/gas/riscv/march-fail-single-char.l
+++ /dev/null
@@ -1,2 +0,0 @@
-.*Assembler messages:
-.*Error: .*unknown (s|h|z|x) ISA extension `(s|h|z|x)'
diff --git a/gas/testsuite/gas/riscv/march-fail-single-prefix-h.d b/gas/testsuite/gas/riscv/march-fail-single-prefix-h.d
new file mode 100644
index 0000000..eb101bd
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-single-prefix-h.d
@@ -0,0 +1,3 @@
+#as: -march=rv32ih
+#source: empty.s
+#error_output: march-fail-single-prefix.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-prefix-s.d b/gas/testsuite/gas/riscv/march-fail-single-prefix-s.d
new file mode 100644
index 0000000..8b6b0d0
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-single-prefix-s.d
@@ -0,0 +1,3 @@
+#as: -march=rv32is
+#source: empty.s
+#error_output: march-fail-single-prefix.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-prefix-x.d b/gas/testsuite/gas/riscv/march-fail-single-prefix-x.d
new file mode 100644
index 0000000..9e87801
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-single-prefix-x.d
@@ -0,0 +1,3 @@
+#as: -march=rv32ix
+#source: empty.s
+#error_output: march-fail-single-prefix.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-prefix-z.d b/gas/testsuite/gas/riscv/march-fail-single-prefix-z.d
new file mode 100644
index 0000000..4ae2692
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-single-prefix-z.d
@@ -0,0 +1,3 @@
+#as: -march=rv32iz
+#source: empty.s
+#error_output: march-fail-single-prefix.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-prefix-zxm.d b/gas/testsuite/gas/riscv/march-fail-single-prefix-zxm.d
new file mode 100644
index 0000000..bdf6f86
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-single-prefix-zxm.d
@@ -0,0 +1,3 @@
+#as: -march=rv32izxm
+#source: empty.s
+#error_output: march-fail-single-prefix.l
diff --git a/gas/testsuite/gas/riscv/march-fail-single-prefix.l b/gas/testsuite/gas/riscv/march-fail-single-prefix.l
new file mode 100644
index 0000000..13942ed
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-single-prefix.l
@@ -0,0 +1,2 @@
+.*Assembler messages:
+.*Error: .*unknown prefixed ISA extension `(s|h|z|x|zxm)'
diff --git a/gas/testsuite/gas/riscv/march-fail-unknown-std.l b/gas/testsuite/gas/riscv/march-fail-unknown-std.l
index 75cdda3..0e9add7 100644
--- a/gas/testsuite/gas/riscv/march-fail-unknown-std.l
+++ b/gas/testsuite/gas/riscv/march-fail-unknown-std.l
@@ -1,2 +1,2 @@
 .*Assembler messages:
-.*Error: .*unknown standard ISA extension `[^eimafdqiglcbjtpvn]'
+.*Error: .*unknown standard and prefixed ISA extension `y'
diff --git a/gas/testsuite/gas/riscv/march-fail-unknown-zxm.d b/gas/testsuite/gas/riscv/march-fail-unknown-zxm.d
new file mode 100644
index 0000000..b3d4603
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-unknown-zxm.d
@@ -0,0 +1,3 @@
+#as: -march=rv32izxmfoo2p0
+#source: empty.s
+#error_output: march-fail-unknown.l
diff --git a/gas/testsuite/gas/riscv/march-fail-unknown.l b/gas/testsuite/gas/riscv/march-fail-unknown.l
index 874b8d4..0cc8096 100644
--- a/gas/testsuite/gas/riscv/march-fail-unknown.l
+++ b/gas/testsuite/gas/riscv/march-fail-unknown.l
@@ -1,2 +1,2 @@
 .*Assembler messages:
-.*Error: .*unknown (s|h|z) ISA extension `(s|h|z)foo'
+.*Error: .*unknown prefixed ISA extension `(s|h|z|zxm)foo'