[Openmp-commits] [openmp] 5e34877 - [OpenMP] Add ident_t flags for compiler OpenMP version

[via Openmp-commits]

Author: Peyton, Jonathan L
Date: 2020-11-05T11:14:25-06:00
New Revision: 5e34877480dfcb8c3cd6f95ac0a46aca417b19bc

URL: https://github.com/llvm/llvm-project/commit/5e34877480dfcb8c3cd6f95ac0a46aca417b19bc
DIFF: https://github.com/llvm/llvm-project/commit/5e34877480dfcb8c3cd6f95ac0a46aca417b19bc.diff

LOG: [OpenMP] Add ident_t flags for compiler OpenMP version

This patch adds the mask and ident_t function to get the
openmp version. It also adds logic to force monotonic:dynamic
behavior when OpenMP version less than 5.0.

The OpenMP version is stored in the format:
major*10+minor e.g., OpenMP 5.0 = 50

Differential Revision: https://reviews.llvm.org/D90632

Added: 
    

Modified: 
    openmp/runtime/src/kmp.h
    openmp/runtime/src/kmp_dispatch.cpp

Removed: 
    


################################################################################
diff  --git a/openmp/runtime/src/kmp.h b/openmp/runtime/src/kmp.h
index 594c5ad88468..ee0e2ccbfaeb 100644
--- a/openmp/runtime/src/kmp.h
+++ b/openmp/runtime/src/kmp.h
@@ -218,6 +218,7 @@ enum {
   KMP_IDENT_ATOMIC_HINT_CONTENDED = 0x020000,
   KMP_IDENT_ATOMIC_HINT_NONSPECULATIVE = 0x040000,
   KMP_IDENT_ATOMIC_HINT_SPECULATIVE = 0x080000,
+  KMP_IDENT_OPENMP_SPEC_VERSION_MASK = 0xFF000000
 };
 
 /*!
@@ -237,6 +238,10 @@ typedef struct ident {
                        The string is composed of semi-colon separated fields
                        which describe the source file, the function and a pair
                        of line numbers that delimit the construct. */
+  // Returns the OpenMP version in form major*10+minor (e.g., 50 for 5.0)
+  kmp_int32 get_openmp_version() {
+    return (((flags & KMP_IDENT_OPENMP_SPEC_VERSION_MASK) >> 24) & 0xFF);
+  }
 } ident_t;
 /*!
 @}

diff  --git a/openmp/runtime/src/kmp_dispatch.cpp b/openmp/runtime/src/kmp_dispatch.cpp
index 610c9a025077..ad71f9969151 100644
--- a/openmp/runtime/src/kmp_dispatch.cpp
+++ b/openmp/runtime/src/kmp_dispatch.cpp
@@ -69,16 +69,24 @@ void __kmp_dispatch_dxo_error(int *gtid_ref, int *cid_ref, ident_t *loc_ref) {
 }
 
 // Returns either SCHEDULE_MONOTONIC or SCHEDULE_NONMONOTONIC
-static inline int __kmp_get_monotonicity(enum sched_type schedule,
+static inline int __kmp_get_monotonicity(ident_t *loc, enum sched_type schedule,
                                          bool use_hier = false) {
   // Pick up the nonmonotonic/monotonic bits from the scheduling type
-  int monotonicity;
-  // default to monotonic
-  monotonicity = SCHEDULE_MONOTONIC;
-  if (SCHEDULE_HAS_NONMONOTONIC(schedule))
+  // TODO: make nonmonotonic when static_steal is fixed
+  int monotonicity = SCHEDULE_MONOTONIC;
+
+  // Let default be monotonic for executables
+  // compiled with OpenMP* 4.5 or less compilers
+  if (loc->get_openmp_version() < 50)
+    monotonicity = SCHEDULE_MONOTONIC;
+
+  if (use_hier)
+    monotonicity = SCHEDULE_MONOTONIC;
+  else if (SCHEDULE_HAS_NONMONOTONIC(schedule))
     monotonicity = SCHEDULE_NONMONOTONIC;
   else if (SCHEDULE_HAS_MONOTONIC(schedule))
     monotonicity = SCHEDULE_MONOTONIC;
+
   return monotonicity;
 }
 
@@ -146,7 +154,7 @@ void __kmp_dispatch_init_algorithm(ident_t *loc, int gtid,
 #endif
 
   /* Pick up the nonmonotonic/monotonic bits from the scheduling type */
-  monotonicity = __kmp_get_monotonicity(schedule, use_hier);
+  monotonicity = __kmp_get_monotonicity(loc, schedule, use_hier);
   schedule = SCHEDULE_WITHOUT_MODIFIERS(schedule);
 
   /* Pick up the nomerge/ordered bits from the scheduling type */
@@ -177,7 +185,7 @@ void __kmp_dispatch_init_algorithm(ident_t *loc, int gtid,
       // Use the scheduling specified by OMP_SCHEDULE (or __kmp_sch_default if
       // not specified)
       schedule = team->t.t_sched.r_sched_type;
-      monotonicity = __kmp_get_monotonicity(schedule, use_hier);
+      monotonicity = __kmp_get_monotonicity(loc, schedule, use_hier);
       schedule = SCHEDULE_WITHOUT_MODIFIERS(schedule);
       // Detail the schedule if needed (global controls are 
diff erentiated
       // appropriately)
@@ -244,7 +252,7 @@ void __kmp_dispatch_init_algorithm(ident_t *loc, int gtid,
     if (schedule == kmp_sch_runtime_simd) {
       // compiler provides simd_width in the chunk parameter
       schedule = team->t.t_sched.r_sched_type;
-      monotonicity = __kmp_get_monotonicity(schedule, use_hier);
+      monotonicity = __kmp_get_monotonicity(loc, schedule, use_hier);
       schedule = SCHEDULE_WITHOUT_MODIFIERS(schedule);
       // Detail the schedule if needed (global controls are 
diff erentiated
       // appropriately)