[PATCH] Fix and extend features of .cpu directive.

[Claudiu Zissulescu <Claudiu dot Zissulescu at synopsys dot com>]

In the below commit, the ARC .cpu directive implementation was
refurbished.

commit bb65a718b601ecfebd1ebe5be71728d5c359c31f
Author: Andrew Burgess <andrew.burgess@embecosm.com>

    gas/arc: Don't rely on bfd list of cpu type for cpu selection

Unfortunately, a small error was introduced, namely, when an option is
given using command line, it may be overwritten/deleted when
interpreting the .cpu pseudo-op, thus, leading to impossibility of
building toolchains for cpus like ARCEM.

This patch solves the above issue, and extends the way how we check
command line options (i.e., features) versus chosen cpu configuration,
emitting errors if one request a feature which is not present in a
specific architecture.

OK to apply?
Claudiu


gas/
2016-11-17  Claudiu Zissulescu  <claziss@synopsys.com>

	* testsuite/gas/arc/cl-warn.s: New file.
	* testsuite/gas/arc/cpu-pseudop-1.d: Likewise.
	* testsuite/gas/arc/cpu-pseudop-1.s: Likewise.
	* testsuite/gas/arc/cpu-pseudop-2.d: Likewise.
	* testsuite/gas/arc/cpu-pseudop-2.s: Likewise.
	* testsuite/gas/arc/cpu-warn2.s: Likewise.
	* config/tc-arc.c (selected_cpu): Initialize.
	(feature_type): New struct.
	(feature_list): New variable.
	(arc_check_feature): New function.
	(arc_select_cpu): Check for .cpu duplicates. Don't overwrite the
	current cpu features. Check if a feature is available for a given
	cpu.
	(md_parse_option): Test if features are available for a given cpu.
---
 gas/config/tc-arc.c                   | 77 +++++++++++++++++++++++++++--------
 gas/testsuite/gas/arc/cl-warn.s       |  5 +++
 gas/testsuite/gas/arc/cpu-pseudop-1.d | 12 ++++++
 gas/testsuite/gas/arc/cpu-pseudop-1.s |  6 +++
 gas/testsuite/gas/arc/cpu-pseudop-2.d | 11 +++++
 gas/testsuite/gas/arc/cpu-pseudop-2.s |  5 +++
 gas/testsuite/gas/arc/cpu-warn2.s     |  4 ++
 7 files changed, 102 insertions(+), 18 deletions(-)
 create mode 100644 gas/testsuite/gas/arc/cl-warn.s
 create mode 100644 gas/testsuite/gas/arc/cpu-pseudop-1.d
 create mode 100644 gas/testsuite/gas/arc/cpu-pseudop-1.s
 create mode 100644 gas/testsuite/gas/arc/cpu-pseudop-2.d
 create mode 100644 gas/testsuite/gas/arc/cpu-pseudop-2.s
 create mode 100644 gas/testsuite/gas/arc/cpu-warn2.s

diff --git a/gas/config/tc-arc.c b/gas/config/tc-arc.c
index 06aee48..376ac43 100644
--- a/gas/config/tc-arc.c
+++ b/gas/config/tc-arc.c
@@ -451,7 +451,23 @@ static const struct cpu_type
 };
 
 /* Information about the cpu/variant we're assembling for.  */
-static struct cpu_type selected_cpu;
+static struct cpu_type selected_cpu = { 0, 0, 0, 0, 0 };
+
+/* A table with options.  */
+static const struct feature_type
+{
+  unsigned feature;
+  unsigned cpus;
+  const char *name;
+}
+  feature_list[] =
+{
+  { ARC_CD, ARC_OPCODE_ARCV2, "code-density" },
+  { ARC_NPS400, ARC_OPCODE_ARC700, "nps400" },
+  { ARC_SPFP, ARC_OPCODE_ARCFPX, "single-precision FPX" },
+  { ARC_DPFP, ARC_OPCODE_ARCFPX, "double-precision FPX" },
+  { ARC_FPUDA, ARC_OPCODE_ARCv2EM, "double assist FP" }
+};
 
 /* Used by the arc_reloc_op table.  Order is important.  */
 #define O_gotoff  O_md1     /* @gotoff relocation.  */
@@ -775,6 +791,27 @@ md_number_to_chars_midend (char *buf, unsigned long long val, int n)
     }
 }
 
+/* Check if a feature is allowed for a specific CPU.  */
+
+static void
+arc_check_feature (void)
+{
+  unsigned i;
+
+  if (!selected_cpu.features
+      || !selected_cpu.name)
+    return;
+  for (i = 0; (i < ARRAY_SIZE (feature_list)); i++)
+    {
+      if ((selected_cpu.features & feature_list[i].feature)
+	  && !(selected_cpu.flags & feature_list[i].cpus))
+	{
+	  as_bad (_("invalid %s option for %s cpu"), feature_list[i].name,
+		  selected_cpu.name);
+	}
+    }
+}
+
 /* Select an appropriate entry from CPU_TYPES based on ARG and initialise
    the relevant static global variables.  Parameter SEL describes where
    this selection originated from.  */
@@ -790,6 +827,10 @@ arc_select_cpu (const char *arg, enum mach_selection_type sel)
   gas_assert (sel != MACH_SELECTION_FROM_DEFAULT
               || mach_selection_mode == MACH_SELECTION_NONE);
 
+  if ((mach_selection_mode == MACH_SELECTION_FROM_CPU_DIRECTIVE)
+      && (sel == MACH_SELECTION_FROM_CPU_DIRECTIVE))
+    as_bad (_("Multiple .cpu directives found"));
+
   /* Look for a matching entry in CPU_TYPES array.  */
   for (i = 0; cpu_types[i].name; ++i)
     {
@@ -807,22 +848,25 @@ arc_select_cpu (const char *arg, enum mach_selection_type sel)
                   && selected_cpu.mach != cpu_types[i].mach)
                 {
                   as_warn (_("Command-line value overrides \".cpu\" directive"));
-                  return;
                 }
+	      return;
             }
 
-          /* Initialise static global data about selected machine type.  */
-          selected_cpu.flags = cpu_types[i].flags;
-          selected_cpu.name = cpu_types[i].name;
-          selected_cpu.features = cpu_types[i].features;
-          selected_cpu.mach = cpu_types[i].mach;
-          cpu_flags = cpu_types[i].eflags;
+	  /* Initialise static global data about selected machine type.  */
+	  selected_cpu.flags = cpu_types[i].flags;
+	  selected_cpu.name = cpu_types[i].name;
+	  selected_cpu.features |= cpu_types[i].features;
+	  selected_cpu.mach = cpu_types[i].mach;
+	  cpu_flags = cpu_types[i].eflags;
           break;
         }
     }
 
   if (!cpu_types[i].name)
     as_fatal (_("unknown architecture: %s\n"), arg);
+
+  /* Check if set features are compatible with the chosen CPU.  */
+  arc_check_feature ();
   gas_assert (cpu_flags != 0);
   selected_cpu.eflags = (arc_initial_eflag & ~EF_ARC_MACH_MSK) | cpu_flags;
   mach_selection_mode = sel;
@@ -3304,11 +3348,8 @@ md_parse_option (int c, const char *arg ATTRIBUTE_UNUSED)
       break;
 
     case OPTION_CD:
-      /* This option has an effect only on ARC EM.  */
-      if (selected_cpu.flags & ARC_OPCODE_ARCv2EM)
-	selected_cpu.features |= ARC_CD;
-      else
-	as_warn (_("Code density option invalid for selected CPU"));
+      selected_cpu.features |= ARC_CD;
+      arc_check_feature ();
       break;
 
     case OPTION_RELAX:
@@ -3317,22 +3358,22 @@ md_parse_option (int c, const char *arg ATTRIBUTE_UNUSED)
 
     case OPTION_NPS400:
       selected_cpu.features |= ARC_NPS400;
+      arc_check_feature ();
       break;
 
     case OPTION_SPFP:
       selected_cpu.features |= ARC_SPFP;
+      arc_check_feature ();
       break;
 
     case OPTION_DPFP:
       selected_cpu.features |= ARC_DPFP;
+      arc_check_feature ();
       break;
 
     case OPTION_FPUDA:
-      /* This option has an effect only on ARC EM.  */
-      if (selected_cpu.flags & ARC_OPCODE_ARCv2EM)
-	selected_cpu.features |= ARC_FPUDA;
-      else
-	as_warn (_("FPUDA invalid for selected CPU"));
+      selected_cpu.features |= ARC_FPUDA;
+      arc_check_feature ();
       break;
 
     /* Dummy options are accepted but have no effect.  */
diff --git a/gas/testsuite/gas/arc/cl-warn.s b/gas/testsuite/gas/arc/cl-warn.s
new file mode 100644
index 0000000..63199cf
--- /dev/null
+++ b/gas/testsuite/gas/arc/cl-warn.s
@@ -0,0 +1,5 @@
+; Test command line option compatibility checking.
+; { dg-do assemble }
+; { dg-options "--mcpu=archs -mdpfp" }
+; { dg-error ".* invalid double-precision FPX option for archs cpu" "" { target arc*-*-* } 0 }
+	nop
diff --git a/gas/testsuite/gas/arc/cpu-pseudop-1.d b/gas/testsuite/gas/arc/cpu-pseudop-1.d
new file mode 100644
index 0000000..09c47c9
--- /dev/null
+++ b/gas/testsuite/gas/arc/cpu-pseudop-1.d
@@ -0,0 +1,12 @@
+#as: -mcpu=arcem -mcode-density -mdpfp
+#objdump: -dp -M dpfp
+
+.*: +file format .*arc.*
+private flags = 0x305: -mcpu=ARCv2EM .*
+
+
+Disassembly of section .text:
+
+00000000 <.text>:
+   0:	4af7                	sub_s	r15,r2,r15
+   2:	3211 00c1           	dsubh12	r1,r2,r3
diff --git a/gas/testsuite/gas/arc/cpu-pseudop-1.s b/gas/testsuite/gas/arc/cpu-pseudop-1.s
new file mode 100644
index 0000000..40217aa
--- /dev/null
+++ b/gas/testsuite/gas/arc/cpu-pseudop-1.s
@@ -0,0 +1,6 @@
+;;; Check if user can use additional command line options.
+	.cpu EM
+	.section	.text
+
+	sub_s r15,r2,r15	;code density instruction
+	dsubh12 r1,r2,r3	;double-precision instruction
diff --git a/gas/testsuite/gas/arc/cpu-pseudop-2.d b/gas/testsuite/gas/arc/cpu-pseudop-2.d
new file mode 100644
index 0000000..3bde329
--- /dev/null
+++ b/gas/testsuite/gas/arc/cpu-pseudop-2.d
@@ -0,0 +1,11 @@
+#as: -mcpu=archs
+#objdump: -dp
+
+.*: +file format .*arc.*
+private flags = 0x306: -mcpu=ARCv2HS .*
+
+
+Disassembly of section .text:
+
+00000000 <.text>:
+   0:	4af7                	sub_s	r15,r2,r15
diff --git a/gas/testsuite/gas/arc/cpu-pseudop-2.s b/gas/testsuite/gas/arc/cpu-pseudop-2.s
new file mode 100644
index 0000000..def89d6
--- /dev/null
+++ b/gas/testsuite/gas/arc/cpu-pseudop-2.s
@@ -0,0 +1,5 @@
+;;; Check if user can use additional command line options.
+	.cpu EM
+	.section	.text
+
+	sub_s r15,r2,r15	;code density instruction
diff --git a/gas/testsuite/gas/arc/cpu-warn2.s b/gas/testsuite/gas/arc/cpu-warn2.s
new file mode 100644
index 0000000..e9ee338
--- /dev/null
+++ b/gas/testsuite/gas/arc/cpu-warn2.s
@@ -0,0 +1,4 @@
+; Test warnings when multiple .cpu pseudo-ops are defined.
+; { dg-do assemble }
+	.cpu EM
+	.cpu HS			;{ dg-error "Error: Multiple .cpu directives found" }
-- 
1.9.1