OpenMP, libgomp: Environment variable syntax extension

This patch considers the environment variable syntax extension for
device-specific variants of environment variables from OpenMP 5.1 (see
OpenMP 5.1 specification, p. 75 and p. 639).  An environment variable (e.g.
OMP_NUM_TEAMS) can have different suffixes:

_DEV (e.g. OMP_NUM_TEAMS_DEV): affects all devices but not the host.
_DEV_<device> (e.g. OMP_NUM_TEAMS_DEV_42): affects only device with
number <device>.
no suffix (e.g. OMP_NUM_TEAMS): affects only the host.

In future OpenMP versions also suffix _ALL will be introduced (see discussion
https://github.com/OpenMP/spec/issues/3179). This is also considered in this
patch:

_ALL (e.g. OMP_NUM_TEAMS_ALL): affects all devices and the host.

The precedence is as follows (descending). For the host:

	1. no suffix
	2. _ALL

For devices:

	1. _DEV_<device>
	2. _DEV
	3. _ALL

That means, _DEV_<device> is used whenever available. Otherwise _DEV is used if
available, and at last _ALL.  If there is no value for any of the variable
variants, default values are used as already implemented before.

This patch concerns parsing (a), storing (b), output (c) and transmission to the
device (d):

(a) The actual number of devices and the numbering are not known when parsing
the environment variables.  Thus all environment variables are iterated and
searched for device-specific ones.
(b) Only configured device-specific variables are stored.  Thus, a linked list
is used.
(c) The output is done in omp_display_env (see specification p. 468f).  Global
ICVs are tagged with [all], see https://github.com/OpenMP/spec/issues/3179.
ICVs which are not global but aren't handled device-specific yet are tagged
with [host].  omp_display_env outputs the initial values of the ICVs.  That is
why a dedicated data structure is introduced for the inital values only
(gomp_initial_icv_list).
(d) Device-specific ICVs are transmitted to the device via GOMP_ADDITIONAL_ICVS.

libgomp/ChangeLog:

	* config/gcn/icv-device.c (omp_get_default_device): Return device-
	specific ICV.
	(omp_get_max_teams): Added for GCN devices.
	(omp_set_num_teams): Likewise.
	(ialias): Likewise.
	* config/nvptx/icv-device.c (omp_get_default_device): Return device-
	specific ICV.
	(omp_get_max_teams): Added for NVPTX devices.
	(omp_set_num_teams): Likewise.
	(ialias): Likewise.
	* env.c (struct gomp_icv_list): New struct to store entries of initial
	ICV values.
	(struct gomp_offload_icv_list): New struct to store entries of device-
	specific ICV values that are copied to the device and back.
	(struct gomp_default_icv_values): New struct to store default values of
	ICVs according to the OpenMP standard.
	(parse_schedule): Generalized for different variants of OMP_SCHEDULE.
	(print_env_var_error): Function that prints an error for invalid values
	for ICVs.
	(parse_unsigned_long_1): Removed getenv.  Generalized.
	(parse_unsigned_long): Likewise.
	(parse_int_1): Likewise.
	(parse_int): Likewise.
	(parse_int_secure): Likewise.
	(parse_unsigned_long_list): Likewise.
	(parse_target_offload): Likewise.
	(parse_bind_var): Likewise.
	(parse_stacksize): Likewise.
	(parse_boolean): Likewise.
	(parse_wait_policy): Likewise.
	(parse_allocator): Likewise.
	(omp_display_env): Extended to output different variants of environment
	variables.
	(print_schedule): New helper function for omp_display_env which prints
	the values of run_sched_var.
	(print_proc_bind): New helper function for omp_display_env which prints
	the values of proc_bind_var.
	(enum gomp_parse_type): Collection of types used for parsing environment
	variables.
	(ENTRY): Preprocess string lengths of environment variables.
	(OMP_VAR_CNT): Preprocess table size.
	(OMP_HOST_VAR_CNT): Likewise.
	(INT_MAX_STR_LEN): Constant for the maximal number of digits of a device
	number.
	(gomp_get_icv_flag): Returns if a flag for a particular ICV is set.
	(gomp_set_icv_flag): Sets a flag for a particular ICV.
	(print_device_specific_icvs): New helper function for omp_display_env to
	print device specific ICV values.
	(get_device_num): New helper function for parse_device_specific.
	Extracts the device number from an environment variable name.
	(get_icv_member_addr): Gets the memory address for a particular member
	of an ICV struct.
	(gomp_get_initial_icv_item): Get a list item of gomp_initial_icv_list.
	(initialize_icvs): New function to initialize a gomp_initial_icvs
	struct.
	(add_initial_icv_to_list): Adds an ICV struct to gomp_initial_icv_list.
	(startswith): Checks if a string starts with a given prefix.
	(initialize_env): Extended to parse the new syntax of environment
	variables.
	* icv-device.c (omp_get_max_teams): Added.
	(ialias): Likewise.
	(omp_set_num_teams): Likewise.
	* icv.c (omp_set_num_teams): Moved to icv-device.c.
	(omp_get_max_teams): Likewise.
	(ialias): Likewise.
	* libgomp-plugin.h (GOMP_DEVICE_NUM_VAR): Removed.
	(GOMP_ADDITIONAL_ICVS): New target-side struct that
	holds the designated ICVs of the target device.
	* libgomp.h (enum gomp_icvs): Collection of ICVs.
	(enum gomp_device_num): Definition of device numbers for _ALL, _DEV, and
	no suffix.
	(enum gomp_env_suffix): Collection of possible suffixes of environment
	variables.
	(struct gomp_initial_icvs): Contains all ICVs for which we need to store
	initial values.
	(struct gomp_default_icv):New struct to hold ICVs for which we need
	to store initial values.
	(struct gomp_icv_list): Definition of a linked list that is used for
	storing ICVs for the devices and also for _DEV, _ALL, and without
	suffix.
	(struct gomp_offload_icvs): New struct to hold ICVs that are copied to
	a device.
	(struct gomp_offload_icv_list): Definition of a linked list that holds
	device-specific ICVs that are copied to devices.
	(gomp_get_initial_icv_item): Get a list item of gomp_initial_icv_list.
	(gomp_get_icv_flag): Returns if a flag for a particular ICV is set.
	* libgomp.texi: Updated.
	* plugin/plugin-gcn.c (GOMP_OFFLOAD_load_image): Extended to read
	further ICVs from the offload image.
	* plugin/plugin-nvptx.c (GOMP_OFFLOAD_load_image): Likewise.
	* target.c (gomp_get_offload_icv_item): Get a list item of
	gomp_offload_icv_list.
	(get_gomp_offload_icvs): New. Returns the ICV values
	depending on the device num and the variable hierarchy.
	(gomp_load_image_to_device): Extended to copy further ICVs to a device.
	* testsuite/libgomp.c-c++-common/icv-5.c: New test.
	* testsuite/libgomp.c-c++-common/icv-6.c: New test.
	* testsuite/libgomp.c-c++-common/icv-7.c: New test.
	* testsuite/libgomp.c-c++-common/icv-8.c: New test.
	* testsuite/libgomp.c-c++-common/omp-display-env-1.c: New test.
	* testsuite/libgomp.c-c++-common/omp-display-env-2.c: New test.

1 files changed, 114 insertions, 0 deletions

diff --git a/libgomp/libgomp.h b/libgomp/libgomp.h
index c243c4d6cf4..75192749dc7 100644
--- a/libgomp/libgomp.h
+++ b/libgomp/libgomp.h
@@ -453,6 +453,38 @@ struct gomp_team_state
 
 struct target_mem_desc;
 
+enum gomp_icvs
+{
+   GOMP_ICV_NTEAMS = 1,
+   GOMP_ICV_SCHEDULE = 2,
+   GOMP_ICV_SCHEDULE_CHUNK_SIZE = 3,
+   GOMP_ICV_DYNAMIC = 4,
+   GOMP_ICV_TEAMS_THREAD_LIMIT = 5,
+   GOMP_ICV_THREAD_LIMIT = 6,
+   GOMP_ICV_NTHREADS = 7,
+   GOMP_ICV_NTHREADS_LIST = 8,
+   GOMP_ICV_NTHREADS_LIST_LEN = 9,
+   GOMP_ICV_BIND = 10,
+   GOMP_ICV_BIND_LIST = 11,
+   GOMP_ICV_BIND_LIST_LEN = 12,
+   GOMP_ICV_MAX_ACTIVE_LEVELS = 13,
+   GOMP_ICV_WAIT_POLICY = 14,
+   GOMP_ICV_STACKSIZE = 15,
+   GOMP_ICV_DEFAULT_DEVICE = 16,
+   GOMP_ICV_CANCELLATION = 17,
+   GOMP_ICV_DISPLAY_AFFINITY = 18,
+   GOMP_ICV_TARGET_OFFLOAD = 19,
+   GOMP_ICV_MAX_TASK_PRIORITY = 20,
+   GOMP_ICV_ALLOCATOR = 21
+};
+
+enum gomp_device_num
+{
+  GOMP_DEVICE_NUM_FOR_DEV = -1,
+  GOMP_DEVICE_NUM_FOR_ALL = -2,
+  GOMP_DEVICE_NUM_FOR_NO_SUFFIX = -3
+};
+
 /* These are the OpenMP 4.0 Internal Control Variables described in
    section 2.3.1.  Those described as having one copy per task are
    stored within the structure; those described as having one copy
@@ -472,6 +504,80 @@ struct gomp_task_icv
   struct target_mem_desc *target_data;
 };
 
+enum gomp_env_suffix
+{
+  GOMP_ENV_SUFFIX_UNKNOWN = 0,
+  GOMP_ENV_SUFFIX_NONE = 1,
+  GOMP_ENV_SUFFIX_DEV = 2,
+  GOMP_ENV_SUFFIX_ALL = 4,
+  GOMP_ENV_SUFFIX_DEV_X = 8
+};
+
+/* Struct that contains all ICVs for which we need to store initial values.
+   Keeping the initial values is needed for omp_display_env.  Moreover initial
+   _DEV and _ALL variants of environment variables are also used to determine
+   actually used values for devices and for the host.  */
+struct gomp_initial_icvs
+{
+  unsigned long *nthreads_var_list;
+  char *bind_var_list;
+  unsigned long nthreads_var;
+  unsigned long nthreads_var_list_len;
+  unsigned long bind_var_list_len;
+  unsigned long stacksize;
+  int run_sched_chunk_size;
+  int default_device_var;
+  int nteams_var;
+  int teams_thread_limit_var;
+  int wait_policy;
+  unsigned int thread_limit_var;
+  enum gomp_schedule_type run_sched_var;
+  bool dyn_var;
+  unsigned char max_active_levels_var;
+  char bind_var;
+};
+
+struct gomp_default_icv
+{
+  unsigned long nthreads_var;
+  enum gomp_schedule_type run_sched_var;
+  int run_sched_chunk_size;
+  int default_device_var;
+  unsigned int thread_limit_var;
+  int nteams_var;
+  int teams_thread_limit_var;
+  bool dyn_var;
+  unsigned char max_active_levels_var;
+  char bind_var;
+};
+
+/*  DEVICE_NUM "-1" is reserved for "_DEV" icvs.
+    DEVICE_NUM "-2" is reserved for "_ALL" icvs.
+    DEVICE_NUM "-3" is reserved for ICVs without suffix.
+    Non-negative DEVICE_NUM is for "_DEV_X" icvs.  */
+struct gomp_icv_list
+{
+  int device_num;
+  uint32_t flags;
+  struct gomp_initial_icvs icvs;
+  struct gomp_icv_list *next;
+};
+
+struct gomp_offload_icvs
+{
+  int device_num;
+  int default_device;
+  int nteams;
+  int teams_thread_limit;
+};
+
+struct gomp_offload_icv_list
+{
+  int device_num;
+  struct gomp_offload_icvs icvs;
+  struct gomp_offload_icv_list *next;
+};
+
 enum gomp_target_offload_t
 {
   GOMP_TARGET_OFFLOAD_DEFAULT,
@@ -503,6 +609,9 @@ extern bool gomp_display_affinity_var;
 extern char *gomp_affinity_format_var;
 extern size_t gomp_affinity_format_len;
 extern uintptr_t gomp_def_allocator;
+extern const struct gomp_default_icv gomp_default_icv_values;
+extern struct gomp_icv_list *gomp_initial_icv_list;
+extern struct gomp_offload_icv_list *gomp_offload_icv_list;
 extern int goacc_device_num;
 extern char *goacc_device_type;
 extern int goacc_default_dims[GOMP_DIM_MAX];
@@ -927,6 +1036,11 @@ extern void gomp_display_affinity_thread (gomp_thread_handle,
 					  struct gomp_team_state *,
 					  unsigned int) __attribute__((cold));
 
+/* env.c */
+
+extern struct gomp_icv_list *gomp_get_initial_icv_item (int dev_num);
+extern bool gomp_get_icv_flag (uint32_t value, enum gomp_icvs icv);
+
 /* iter.c */
 
 extern int gomp_iter_static_next (long *, long *);