op_avx: use MCA enum flags instead of integer values

MCA enums make it easier for users to see/set MCA flag values.  Also
add "op_avx_capabilities" read-only MCA var that shows what is supported
on your platform, regardless of what value the user has set in
"opal_avx_support".

For example, ompi_output shows all the valid values:

```
$ ompi_info --all --parsable | grep _avx_
mca:op:avx:param:op_avx_capabilities:value:SSE,SSE2,SSE3,SSE4.1,AVX
mca:op:avx:param:op_avx_capabilities:source:default
mca:op:avx:param:op_avx_capabilities:status:read-only
mca:op:avx:param:op_avx_capabilities:level:4
mca:op:avx:param:op_avx_capabilities:help:Level of SSE/MMX/AVX support available in the current environment
mca:op:avx:param:op_avx_capabilities:enumerator:value:1:SSE
mca:op:avx:param:op_avx_capabilities:enumerator:value:2:SSE2
mca:op:avx:param:op_avx_capabilities:enumerator:value:4:SSE3
mca:op:avx:param:op_avx_capabilities:enumerator:value:8:SSE4.1
mca:op:avx:param:op_avx_capabilities:enumerator:value:16:AVX
mca:op:avx:param:op_avx_capabilities:enumerator:value:32:AVX2
mca:op:avx:param:op_avx_capabilities:enumerator:value:256:AVX512F
mca:op:avx:param:op_avx_capabilities:enumerator:value:512:AVX512BW
mca:op:avx:param:op_avx_capabilities:deprecated:no
mca:op:avx:param:op_avx_capabilities:type:int
mca:op:avx:param:op_avx_capabilities:disabled:false
mca:op:avx:param:op_avx_support:value:SSE,SSE2,SSE3,SSE4.1,AVX
mca:op:avx:param:op_avx_support:source:default
mca:op:avx:param:op_avx_support:status:read-only
mca:op:avx:param:op_avx_support:level:4
mca:op:avx:param:op_avx_support:help:Level of SSE/MMX/AVX support to be used, capped by the local architecture capabilities
mca:op:avx:param:op_avx_support:enumerator:value:1:SSE
mca:op:avx:param:op_avx_support:enumerator:value:2:SSE2
mca:op:avx:param:op_avx_support:enumerator:value:4:SSE3
mca:op:avx:param:op_avx_support:enumerator:value:8:SSE4.1
mca:op:avx:param:op_avx_support:enumerator:value:16:AVX
mca:op:avx:param:op_avx_support:enumerator:value:32:AVX2
mca:op:avx:param:op_avx_support:enumerator:value:256:AVX512F
mca:op:avx:param:op_avx_support:enumerator:value:512:AVX512BW
mca:op:avx:param:op_avx_support:deprecated:no
mca:op:avx:param:op_avx_support:type:int
mca:op:avx:param:op_avx_support:disabled:false
```

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>

Author: jsquyres

ompi/mca/op/avx/op_avx.h

@@ -46,7 +46,8 @@ typedef struct {
        avxs; replace them with whatever is relevant for your
        component. */
 
-    uint32_t flags; /* AVX capabilities supported by the processor */
+    uint32_t supported; /* AVX capabilities supported by the environment */
+    uint32_t flags; /* AVX capabilities requested by this process */
 } ompi_op_avx_component_t;
 
 /**

ompi/mca/op/avx/op_avx_component.c

@@ -4,6 +4,7 @@
  *                         reserved.
  * Copyright (c) 2020      Research Organization for Information Science
  *                         and Technology (RIST).  All rights reserved.
+ * Copyright (c) 2021      Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -20,6 +21,7 @@
 #include "ompi_config.h"
 
 #include "opal/util/printf.h"
+#include "ompi/include/mpi_portable_platform.h"
 
 #include "ompi/constants.h"
 #include "ompi/op/op.h"
@@ -35,6 +37,18 @@ static struct ompi_op_base_module_1_0_0_t *
     avx_component_op_query(struct ompi_op_t *op, int *priority);
 static int avx_component_register(void);
 
+static mca_base_var_enum_value_flag_t avx_support_flags[] = {
+    { .flag = 0x001, .string = "SSE" },
+    { .flag = 0x002, .string = "SSE2" },
+    { .flag = 0x004, .string = "SSE3" },
+    { .flag = 0x008, .string = "SSE4.1" },
+    { .flag = 0x010, .string = "AVX" },
+    { .flag = 0x020, .string = "AVX2" },
+    { .flag = 0x100, .string = "AVX512F" },
+    { .flag = 0x200, .string = "AVX512BW" },
+    { .flag = 0,     .string = NULL },
+};
+
 /**
  * A slightly modified code from
  * https://software.intel.com/en-us/articles/how-to-detect-new-instruction-support-in-the-4th-generation-intel-core-processor-family
@@ -177,15 +191,38 @@ static int avx_component_close(void)
 static int
 avx_component_register(void)
 {
-    int32_t requested_flags = mca_op_avx_component.flags = has_intel_AVX_features();
+    mca_op_avx_component.supported =
+        mca_op_avx_component.flags = has_intel_AVX_features();
+
+    // MCA var enum flag for conveniently seeing SSE/MMX/AVX support
+    // values
+    mca_base_var_enum_flag_t *new_enum_flag;
+    (void) mca_base_var_enum_create_flag("op_avx_support_flags",
+                                         avx_support_flags, &new_enum_flag);
+    (void) mca_base_var_enum_register("ompi", "op", "avx", "support_flags",
+                                      &new_enum_flag);
+
+    (void) mca_base_component_var_register(&mca_op_avx_component.super.opc_version,
+                                           "capabilities",
+                                           "Level of SSE/MMX/AVX support available in the current environment",
+                                           MCA_BASE_VAR_TYPE_INT,
+                                           &(new_enum_flag->super), 0, 0,
+                                           OPAL_INFO_LVL_4,
+                                           MCA_BASE_VAR_SCOPE_CONSTANT,
+                                           &mca_op_avx_component.supported);
+
     (void) mca_base_component_var_register(&mca_op_avx_component.super.opc_version,
                                            "support",
-                                           "Level of SSE/MMX/AVX support to be used (combination of processor capabilities as follow SSE 0x01, SSE2 0x02, SSE3 0x04, SSE4.1 0x08, AVX 0x010, AVX2 0x020, AVX512F 0x100, AVX512BW 0x200) capped by the local architecture capabilities",
-                                           MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
-                                           OPAL_INFO_LVL_6,
+                                           "Level of SSE/MMX/AVX support to be used, capped by the local architecture capabilities",
+                                           MCA_BASE_VAR_TYPE_INT,
+                                           &(new_enum_flag->super), 0, 0,
+                                           OPAL_INFO_LVL_4,
                                            MCA_BASE_VAR_SCOPE_LOCAL,
                                            &mca_op_avx_component.flags);
-    mca_op_avx_component.flags &= requested_flags;
+    OBJ_RELEASE(new_enum_flag);
+
+    mca_op_avx_component.flags &= mca_op_avx_component.supported;
+
     return OMPI_SUCCESS;
 }