libgomp: Extend OMP_ALLOCATOR, add affinity env var doc

Support OpenMP 5.1's syntax for OMP_ALLOCATOR as well,
which permits besides predefined allocators also
predefined memspaces optionally followed by traits.

Additionally, this commit adds the previously lacking
documentation for OMP_ALLOCATOR, OMP_AFFINITY_FORMAT
and OMP_DISPLAY_AFFINITY.

libgomp/ChangeLog:

	* env.c (gomp_def_allocator_envvar): New var.
	(parse_allocator): Handle OpenMP 5.1 syntax.
	(cleanup_env): New.
	(omp_display_env): Output gomp_def_allocator_envvar
	for an allocator with traits.
	* libgomp.texi (OMP_ALLOCATOR, OMP_AFFINITY_FORMAT,
	OMP_DISPLAY_AFFINITY): New.
	* testsuite/libgomp.c/allocator-1.c: New test.
	* testsuite/libgomp.c/allocator-2.c: New test.
	* testsuite/libgomp.c/allocator-3.c: New test.
	* testsuite/libgomp.c/allocator-4.c: New test.
	* testsuite/libgomp.c/allocator-5.c: New test.
	* testsuite/libgomp.c/allocator-6.c: New test.

libgomp/env.c

@@ -112,6 +112,7 @@ unsigned long gomp_bind_var_list_len;
 void **gomp_places_list;
 unsigned long gomp_places_list_len;
 uintptr_t gomp_def_allocator = omp_default_mem_alloc;
+char *gomp_def_allocator_envvar = NULL;
 int gomp_debug_var;
 unsigned int gomp_num_teams_var;
 int gomp_nteams_var;
@@ -1233,8 +1234,12 @@ parse_affinity (bool ignore)
 static bool
 parse_allocator (const char *env, const char *val, void *const params[])
 {
+  const char *orig_val = val;
   uintptr_t *ret = (uintptr_t *) params[0];
   *ret = omp_default_mem_alloc;
+  bool memspace = false;
+  size_t ntraits = 0;
+  omp_alloctrait_t *traits;
 
   if (val == NULL)
     return false;
@@ -1243,28 +1248,169 @@ parse_allocator (const char *env, const char *val, void *const params[])
     ++val;
   if (0)
     ;
-#define C(v) \
+#define C(v, m) \
   else if (strncasecmp (val, #v, sizeof (#v) - 1) == 0)	\
     {							\
       *ret = v;						\
       val += sizeof (#v) - 1;				\
+      memspace = m;					\
     }
-  C (omp_default_mem_alloc)
-  C (omp_large_cap_mem_alloc)
-  C (omp_const_mem_alloc)
-  C (omp_high_bw_mem_alloc)
-  C (omp_low_lat_mem_alloc)
-  C (omp_cgroup_mem_alloc)
-  C (omp_pteam_mem_alloc)
-  C (omp_thread_mem_alloc)
+  C (omp_default_mem_alloc, false)
+  C (omp_large_cap_mem_alloc, false)
+  C (omp_const_mem_alloc, false)
+  C (omp_high_bw_mem_alloc, false)
+  C (omp_low_lat_mem_alloc, false)
+  C (omp_cgroup_mem_alloc, false)
+  C (omp_pteam_mem_alloc, false)
+  C (omp_thread_mem_alloc, false)
+  C (omp_default_mem_space, true)
+  C (omp_large_cap_mem_space, true)
+  C (omp_const_mem_space, true)
+  C (omp_high_bw_mem_space, true)
+  C (omp_low_lat_mem_space, true)
 #undef C
   else
-    val = "X";
+    goto invalid;
+  if (memspace && *val == ':')
+    {
+      ++val;
+      const char *cp = val;
+      while (*cp != '\0')
+	{
+	  if (*cp == '=')
+	    ++ntraits;
+	  ++cp;
+	}
+      traits = gomp_alloca (ntraits * sizeof (omp_alloctrait_t));
+      size_t n = 0;
+      while (*val != '\0')
+	{
+#define C(v) \
+	  else if (strncasecmp (val, #v "=", sizeof (#v)) == 0)	\
+	    {							\
+	      val += sizeof (#v);				\
+	      traits[n].key = omp_atk_ ## v;
+#define V(v) \
+	    else if (strncasecmp (val, #v, sizeof (#v) - 1) == 0)	\
+	      {								\
+		val += sizeof (#v) - 1;					\
+		traits[n].value = omp_atv_ ## v;			\
+	      }
+	  if (0)
+	    ;
+	  C (sync_hint)
+	      if (0)
+		;
+	      V (contended)
+	      V (uncontended)
+	      V (serialized)
+	      V (private)
+	      else
+		goto invalid;
+	    }
+	  C (alignment)
+	      char *end;
+	      errno = 0;
+	      traits[n].value = strtol (val, &end, 10);
+	      if (errno || end == val || traits[n].value <= 0)
+		goto invalid;
+	      val = end;
+	    }
+	  C (access)
+	      if (0)
+		;
+	      V (all)
+	      V (cgroup)
+	      V (pteam)
+	      V (thread)
+	      else
+		goto invalid;
+	    }
+	  C (pool_size)
+	      char *end;
+	      errno = 0;
+	      traits[n].value = strtol (val, &end, 10);
+	      if (errno || end == val || traits[n].value <= 0)
+		goto invalid;
+	      val = end;
+	    }
+	  C (fallback)
+	      if (0)
+		;
+	      V (default_mem_fb)
+	      V (null_fb)
+	      V (abort_fb)
+	      V (allocator_fb)
+	      else
+		goto invalid;
+	    }
+	  /* Ignore fb_data, which expects an allocator handle.  */
+	  C (pinned)
+	      if (0)
+		;
+	      V (true)
+	      V (false)
+	      else
+		goto invalid;
+	    }
+	  C (partition)
+	      if (0)
+		;
+	      V (environment)
+	      V (nearest)
+	      V (blocked)
+	      V (interleaved)
+	      else
+		goto invalid;
+	    }
+	  else
+	    goto invalid;
+	  if (*val != ',')
+	    break;
+	  ++val;
+	  ++n;
+	  if (*val == '\0')
+	    goto invalid;
+	}
+#undef C
+#undef V
+    }
+  else if (memspace)
+    switch (*ret)
+      {
+	case omp_default_mem_space: *ret = omp_default_mem_alloc; break;
+	case omp_large_cap_mem_space: *ret = omp_large_cap_mem_alloc; break;
+	case omp_const_mem_space: *ret = omp_const_mem_alloc; break;
+	case omp_high_bw_mem_space: *ret = omp_high_bw_mem_alloc; break;
+	case omp_low_lat_mem_space: *ret = omp_low_lat_mem_alloc; break;
+	default: __builtin_unreachable ();
+      }
   while (isspace ((unsigned char) *val))
     ++val;
   if (*val == '\0')
-    return true;
-  print_env_var_error (env, val);
+    {
+      if (ntraits)
+	{
+	  *ret = omp_init_allocator (*ret, ntraits, traits);
+	  if (*ret == omp_null_allocator)
+	    {
+	      gomp_error ("Allocator of environment variable %.*s cannot be "
+			  "created, using omp_default_mem_alloc instead",
+			  (int) (orig_val - env - 1), env);
+	      *ret = omp_default_mem_alloc;
+	    }
+	  else
+	    gomp_def_allocator_envvar = strdup (orig_val);
+	}
+      return true;
+    }
+invalid:
+  int len = (orig_val - env - 1);
+  if (*val == '\0')
+    gomp_error ("Missing value at the end of environment variable %s", env);
+  else
+    gomp_error ("Invalid value for environment variable %.*s when parsing: %s",
+		len, env, val);
   *ret = omp_default_mem_alloc;
   return false;
 }
@@ -1784,7 +1930,11 @@ omp_display_env (int verbose)
     C (omp_pteam_mem_alloc)
     C (omp_thread_mem_alloc)
 #undef C
-    default: break;
+    /* For an OMP_ALLOCATOR with traits, '' will be output.  */
+    default:
+      if (gomp_def_allocator_envvar)
+	fputs (gomp_def_allocator_envvar, stderr);
+      break;
     }
   fputs ("'\n", stderr);
 
@@ -2036,6 +2186,16 @@ startswith (const char *str, const char *prefix)
   return strncmp (str, prefix, strlen (prefix)) == 0;
 }
 
+static void __attribute__((destructor))
+cleanup_env (void)
+{
+  if (gomp_def_allocator_envvar != NULL)
+    {
+      free (gomp_def_allocator_envvar);
+      omp_destroy_allocator (gomp_def_allocator);
+    }
+}
+
 static void __attribute__((constructor))
 initialize_env (void)
 {

libgomp/libgomp.texi

@@ -1937,7 +1937,10 @@ section 4 of the OpenMP specification in version 4.5, while those
 beginning with @env{GOMP_} are GNU extensions.
 
 @menu
+* OMP_ALLOCATOR::           Set the default allocator
+* OMP_AFFINITY_FORMAT::     Set the format string used for affinity display
 * OMP_CANCELLATION::        Set whether cancellation is activated
+* OMP_DISPLAY_AFFINITY::    Display thread affinity information
 * OMP_DISPLAY_ENV::         Show OpenMP version and environment variables
 * OMP_DEFAULT_DEVICE::      Set the device used in target regions
 * OMP_DYNAMIC::             Dynamic adjustment of threads
@@ -1962,6 +1965,125 @@ beginning with @env{GOMP_} are GNU extensions.
 @end menu
 
 
+@node OMP_ALLOCATOR
+@section @env{OMP_ALLOCATOR} -- Set the default allocator
+@cindex Environment Variable
+@table @asis
+@item @emph{Description}:
+Sets the default allocator that is used when no allocator has been specified
+in the @code{allocate} or @code{allocator} clause or if an OpenMP memory
+routine is invoked with the @code{omp_null_allocator} allocator.
+If unset, @code{omp_default_mem_alloc} is used.
+
+The value can either be a predefined allocator or a predefined memory space
+or a predefined memory space followed by a colon and a comma-separated list
+of memory trait and value pairs, separated by @code{=}.
+
+@multitable @columnfractions .45 .45
+@headitem Predefined allocators @tab Predefined memory spaces
+@item omp_default_mem_alloc     @tab omp_default_mem_space
+@item omp_large_cap_mem_alloc   @tab omp_large_cap_mem_space
+@item omp_const_mem_alloc       @tab omp_const_mem_space
+@item omp_high_bw_mem_alloc     @tab omp_high_bw_mem_space
+@item omp_low_lat_mem_alloc     @tab omp_low_lat_mem_space
+@item omp_cgroup_mem_alloc      @tab --
+@item omp_pteam_mem_alloc       @tab --
+@item omp_thread_mem_alloc      @tab --
+@end multitable
+
+@multitable @columnfractions .30 .60
+@headitem Trait @tab Allowed values
+@item @code{sync_hint} @tab @code{contended}, @code{uncontended},
+                            @code{serialized}, @code{private}
+@item @code{alignment} @tab Positive integer being a power of two
+@item @code{access}    @tab @code{all}, @code{cgroup},
+                            @code{pteam}, @code{thread}
+@item @code{pool_size} @tab Positive integer
+@item @code{fallback}  @tab @code{default_mem_fb}, @code{null_fb},
+                            @code{abort_fb}, @code{allocator_fb}
+@item @code{fb_data}   @tab @emph{unsupported as it needs an allocator handle}
+@item @code{pinned}    @tab @code{true}, @code{false}
+@item @code{partition} @tab @code{environment}, @code{nearest},
+                            @code{blocked}, @code{interleaved}
+@end multitable
+
+Examples:
+@smallexample
+OMP_ALLOCATOR=omp_high_bw_mem_alloc
+OMP_ALLOCATOR=omp_large_cap_mem_space
+OMP_ALLOCATR=omp_low_lat_mem_space:pinned=true,partition=nearest
+@end smallexample
+
+@c @item @emph{See also}:
+
+@item @emph{Reference}:
+@uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.21
+@end table
+
+
+
+@node OMP_AFFINITY_FORMAT
+@section @env{OMP_AFFINITY_FORMAT} -- Set the format string used for affinity display
+@cindex Environment Variable
+@table @asis
+@item @emph{Description}:
+Sets the format string used when displaying OpenMP thread affinity information.
+Special values are output using @code{%} followed by an optional size
+specification and then either the single-character field type or its long
+name enclosed in curly braces; using @code{%%} will display a literal percent.
+The size specification consists of an optional @code{0.} or @code{.} followed
+by a positive integer, specifing the minimal width of the output.  With
+@code{0.} and numerical values, the output is padded with zeros on the left;
+with @code{.}, the output is padded by spaces on the left; otherwise, the
+output is padded by spaces on the right.  If unset, the value is
+``@code{level %L thread %i affinity %A}''.
+
+Supported field types are:
+
+@multitable @columnfractions .10 .25 .60
+@item t @tab team_num @tab value returned by @code{omp_get_team_num}
+@item T @tab num_teams @tab value returned by @code{omp_get_num_teams}
+@item L @tab nesting_level @tab value returned by @code{omp_get_level}
+@item n @tab thread_num @tab value returned by @code{omp_get_thread_num}
+@item N @tab num_threads @tab value returned by @code{omp_get_num_threads}
+@item a @tab ancestor_tnum
+      @tab value returned by
+           @code{omp_get_ancestor_thread_num(omp_get_level()-1)}
+@item H @tab host @tab name of the host that executes the thread
+@item P @tab process_id @tab process identifier
+@item i @tab native_thread_id @tab native thread identifier
+@item A @tab thread_affinity
+      @tab comma separated list of integer values or ranges, representing the
+           processors on which a process might execute, subject to affinity
+           mechanisms
+@end multitable
+
+For instance, after setting
+
+@smallexample
+OMP_AFFINITY_FORMAT="%0.2a!%n!%.4L!%N;%.2t;%0.2T;%@{team_num@};%@{num_teams@};%A"
+@end smallexample
+
+with either @code{OMP_DISPLAY_AFFINITY} being set or when calling
+@code{omp_display_affinity} with @code{NULL} or an empty string, the program
+might display the following:
+
+@smallexample
+00!0!   1!4; 0;01;0;1;0-11
+00!3!   1!4; 0;01;0;1;0-11
+00!2!   1!4; 0;01;0;1;0-11
+00!1!   1!4; 0;01;0;1;0-11
+@end smallexample
+
+@item @emph{See also}:
+@ref{OMP_DISPLAY_AFFINITY}
+
+@item @emph{Reference}:
+@uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.14
+@end table
+
+
+
 @node OMP_CANCELLATION
 @section @env{OMP_CANCELLATION} -- Set whether cancellation is activated
 @cindex Environment Variable
@@ -1979,6 +2101,26 @@ if unset, cancellation is disabled and the @code{cancel} construct is ignored.
 
 
 
+@node OMP_DISPLAY_AFFINITY
+@section @env{OMP_DISPLAY_AFFINITY} -- Display thread affinity information
+@cindex Environment Variable
+@table @asis
+@item @emph{Description}:
+If set to @code{FALSE} or if unset, affinity displaying is disabled.
+If set to @code{TRUE}, the runtime will display affinity information about
+OpenMP threads in a parallel region upon entering the region and every time
+any change occurs.
+
+@item @emph{See also}:
+@ref{OMP_AFFINITY_FORMAT}
+
+@item @emph{Reference}:
+@uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.13
+@end table
+
+
+
+
 @node OMP_DISPLAY_ENV
 @section @env{OMP_DISPLAY_ENV} -- Show OpenMP version and environment variables
 @cindex Environment Variable

libgomp/testsuite/libgomp.c/allocator-1.c

@@ -0,0 +1,15 @@
+/* { dg-set-target-env-var OMP_ALLOCATOR "omp_large_cap_mem_alloc" } */
+/* { dg-set-target-env-var OMP_DISPLAY_ENV "true" } */
+
+/* { dg-output ".\\\[host\\\] OMP_ALLOCATOR = 'omp_large_cap_mem_alloc'.*" } */
+
+#include <omp.h>
+
+int
+main ()
+{
+  omp_allocator_handle_t m = omp_get_default_allocator ();
+  if (m != omp_large_cap_mem_alloc)
+    __builtin_abort ();
+  return 0;
+}

libgomp/testsuite/libgomp.c/allocator-2.c

@@ -0,0 +1,17 @@
+/* { dg-set-target-env-var OMP_ALLOCATOR "omp_large_cap_mem_space" } */
+/* { dg-set-target-env-var OMP_DISPLAY_ENV "true" } */
+
+/* Expect omp_large_cap_mem_alloc as allocator for omp_large_cap_mem_space. */
+/* { dg-output ".\\\[host\\\] OMP_ALLOCATOR = 'omp_large_cap_mem_alloc'.*" } */
+#include <omp.h>
+
+int
+main ()
+{
+  omp_allocator_handle_t m = omp_get_default_allocator ();
+  /* Without traits, omp_large_cap_mem_space implies
+     omp_large_cap_mem_alloc.  */
+  if (m != omp_large_cap_mem_alloc)
+    __builtin_abort ();
+  return 0;
+}

libgomp/testsuite/libgomp.c/allocator-3.c

@@ -0,0 +1,27 @@
+/* { dg-set-target-env-var OMP_ALLOCATOR "  omp_default_mem_space:alignment=512,pinned=false,access=all  " } */
+/* { dg-set-target-env-var OMP_DISPLAY_ENV "true" } */
+
+/* We copied the environment string; hence, it may contain white space.  */
+/* { dg-output ".\\\[host\\\] OMP_ALLOCATOR = '  omp_default_mem_space:alignment=512,pinned=false,access=all  '.*" } */
+
+#include <stdint.h>
+#include <omp.h>
+
+int
+main ()
+{
+  int *a, *b;
+  a = omp_alloc (sizeof (int) * 1024, omp_null_allocator);
+
+  omp_allocator_handle_t m = omp_get_default_allocator ();
+  b = omp_alloc (sizeof (int) * 1024, m);
+
+  if ((uintptr_t) a % 512 != 0)
+    __builtin_abort ();
+
+  if ((uintptr_t) b % 512 != 0)
+    __builtin_abort ();
+  omp_free (a, omp_null_allocator);
+  omp_free (b, m);
+  return 0;
+}

libgomp/testsuite/libgomp.c/allocator-4.c

@@ -0,0 +1,15 @@
+/* { dg-set-target-env-var OMP_ALLOCATOR "omp_const_mem_space:alignment=3,pinned=" } */
+
+/* { dg-output ".*libgomp: Missing value at the end of environment variable OMP_ALLOCATOR=omp_const_mem_space:alignment=3,pinned=.*" } */
+/* OMP_ALLOCATOR syntax error -> use omp_default_mem_alloc.  */
+
+#include <omp.h>
+
+int
+main ()
+{
+  omp_allocator_handle_t m = omp_get_default_allocator ();
+  if (m != omp_default_mem_alloc)
+    __builtin_abort ();
+  return 0;
+}

libgomp/testsuite/libgomp.c/allocator-5.c

@@ -0,0 +1,15 @@
+/* { dg-set-target-env-var OMP_ALLOCATOR "omp_const_mem_space:access=none,pinned=false" } */
+
+/* { dg-output ".*libgomp: Invalid value for environment variable OMP_ALLOCATOR when parsing: none,pinned=false.*" } */
+/* OMP_ALLOCATOR syntax error -> use omp_default_mem_alloc.  */
+
+#include <omp.h>
+
+int
+main ()
+{
+  omp_allocator_handle_t m = omp_get_default_allocator ();
+  if (m != omp_default_mem_alloc)
+    __builtin_abort ();
+  return 0;
+}

libgomp/testsuite/libgomp.c/allocator-6.c

@@ -0,0 +1,15 @@
+/* { dg-set-target-env-var OMP_ALLOCATOR "omp_default_mem_space:alignment=3" } */
+
+/* { dg-output ".*libgomp: Allocator of environment variable OMP_ALLOCATOR cannot be created, using omp_default_mem_alloc instead.*" } */
+/* OMP_ALLOCATOR's alignment is not power of 2 -> use omp_default_mem_alloc.  */
+
+#include <omp.h>
+
+int
+main ()
+{
+  omp_allocator_handle_t m = omp_get_default_allocator ();
+  if (m != omp_default_mem_alloc)
+    __builtin_abort ();
+  return 0;
+}