[ARC] Fix handling of cpu=... disassembler option value

There is a bug in handling of cpu=... disassembler option in case there are
other options after it, for example, `cpu=EM,dsp'.  In this case `EM,dsp' is
treated as an option value, and strcasecmp reports is as non-equal to "EM".
This is fixed by using disassembler_options_cmp function, which compares string
treating `,' the same way as `\0'.

This function also solves a problem with option order in parse_option.
Previously, if several option had same prefix (e.g. fpud, fpuda), then the
longer one should have been compared first, otherwise when longer option is
passed it would be treated as a short one, because

  CONST_STRNEQ ("fpud", "fpuda")

would be true.  The order of options was correct for ARC, so there were no
bugs per se, but with disassembler_option_cmp there is no risk of such a bug
being introduced in the future.

opcodes/ChangeLog:

yyyy-mm-dd  Anton Kolesov  <Anton.Kolesov@synopsys.com>

	* arc-dis.c (parse_option): Use disassembler_options_cmp to compare
	disassembler option strings.
	(parse_cpu_option): Likewise.

binutils/ChangeLog

yyyy-mm-dd  Anton Kolesov  <Anton.Kolesov@synopsys.com>

	* testsuite/binutils-all/arc/double_store.s: New file.
	* testsuite/binutils-all/arc/objdump.exp: Tests for disassembler
	options.
	(do_objfile): New function.
	(check_assembly): Likewise.

2 files changed, 62 insertions, 17 deletions

diff --git a/binutils/testsuite/binutils-all/arc/double_store.s b/binutils/testsuite/binutils-all/arc/double_store.s
new file mode 100644
index 0000000000..794d7e89f0
--- /dev/null
+++ b/binutils/testsuite/binutils-all/arc/double_store.s
@@ -0,0 +1,6 @@
+.cpu HS
+.section .text
+.global __start
+__start:
+    std r0r1, [r3]
+
diff --git a/binutils/testsuite/binutils-all/arc/objdump.exp b/binutils/testsuite/binutils-all/arc/objdump.exp
index ca36431871..2037b2b483 100644
--- a/binutils/testsuite/binutils-all/arc/objdump.exp
+++ b/binutils/testsuite/binutils-all/arc/objdump.exp
@@ -25,31 +25,70 @@ if {[which $OBJDUMP] == 0} then {
 
 send_user "Version [binutil_version $OBJDUMP]"
 
-###########################
-# Set up the test of dsp.s
-###########################
+# Helper functions
 
-if {![binutils_assemble $srcdir/$subdir/dsp.s tmpdir/dsp.o]} then {
-    return
+# Create object file from the assembly source.
+proc do_objfile { srcfile } {
+    global srcdir
+    global subdir
+
+    set objfile [regsub -- "\.s$" $srcfile ".o"]
+
+    if {![binutils_assemble $srcdir/$subdir/$srcfile tmpdir/$objfile]} then {
+	return
+    }
+
+    if [is_remote host] {
+	set objfile [remote_download host tmpdir/$objfile]
+    } else {
+	set objfile tmpdir/$objfile
+    }
+
+    return $objfile
 }
 
-if [is_remote host] {
-    set objfile [remote_download host tmpdir/dsp.o]
-} else {
-    set objfile tmpdir/dsp.o
+# Ensure that disassembler output includes EXPECTED lines.
+proc check_assembly { testname objfile expected { disas_flags "" } } {
+    global OBJDUMP
+    global OBJDUMPFLAGS
+
+    set got [binutils_run $OBJDUMP "$OBJDUMPFLAGS --disassemble $disas_flags \
+	$objfile"]
+
+    if [regexp $expected $got] then {
+	pass $testname
+    } else {
+	fail $testname
+    }
 }
 
 # Make sure that a warning message is generated (because the disassembly does
 # not match the assembled instructions, which has happened because the user
 # has not specified a -M option on the disassembler command line, and so the
 # disassembler has had to guess as the instruction class in use).
-
-set got [binutils_run $OBJDUMP "$OBJDUMPFLAGS --disassemble $objfile"]
-
 set want "Warning: disassembly.*vmac2hnfr\[ \t\]*r0,r2,r4.*dmulh12.f\[ \t\]*r0,r2,r4.*dmulh11.f"
+check_assembly "Warning test" [do_objfile dsp.s] $want
+
+set double_store_hs_expected {std\s*r0r1,\[r3\]}
+set objfile [do_objfile double_store.s]
+check_assembly "arc double_store default -M" $objfile \
+    $double_store_hs_expected
+check_assembly "arc double_store -Mcpu=hs" $objfile \
+    $double_store_hs_expected "-Mcpu=hs"
+check_assembly "arc double_store -Mcpu=hs38_linux" $objfile \
+    $double_store_hs_expected "-Mcpu=hs38_linux"
+set double_store_em_expected ".long 0x1b000006"
+check_assembly "arc double_store -Mcpu=em" $objfile \
+    $double_store_em_expected "-Mcpu=em"
+check_assembly "arc double_store -Mcpu=em4_dmips" $objfile \
+    $double_store_em_expected "-Mcpu=em4_dmips"
+# Test to ensure that only value up to the next `,' is checked.  There used to
+# be a bug, where whole `em,fpus' was compared against known CPU values, and
+# that comparison would fail.  When this bug is present, whole cpu= option will
+# be ignored and instruction will be disassembled as ARC HS.
+check_assembly "arc double_store -Mcpu=em,fpus" $objfile \
+    $double_store_em_expected "-Mcpu=em,fpus"
+# Make sure that the last cpu= value is used.
+check_assembly "arc double_store -Mcpu=hs,cpu=em" $objfile \
+    $double_store_em_expected "-Mcpu=hs,cpu=em"
 
-if [regexp $want $got] then {
-    pass "Warning test"
-} else {
-    fail "Warning test"
-}