Fix assert "DeclRefExpr for Decl not entered in LocalDeclMap?"

Currently compiler assert when passing variable "memspace" in
omp_init_allocator.

omp_allocator_handle_t alloc=omp_init_allocator(memspace,1,traits)

The problem is memspace is not mapping to the target region.  During
the call to emitAllocatorInit, calls to EmitVarDecl for "alloc", then
emit initialization of "alloc" that cause to assert.

If I understant correct, it is not necessary to emit variable
initialization, since "allocator" is private to target region.

To fix this call CGF.EmitAutoVarAlloca(allocator) instead
CGF.EmitVarDecl(allocator).

Differential Revision: https://reviews.llvm.org/D151743

Author: jyu2-git

clang/lib/CodeGen/CGOpenMPRuntime.cpp

@@ -6041,7 +6041,7 @@ void CGOpenMPRuntime::emitUsesAllocatorsInit(CodeGenFunction &CGF,
                               CGM.getModule(), OMPRTL___kmpc_init_allocator),
                           {ThreadId, MemSpaceHandle, NumTraits, Traits});
   // Store to allocator.
-  CGF.EmitVarDecl(*cast<VarDecl>(
+  CGF.EmitAutoVarAlloca(*cast<VarDecl>(
       cast<DeclRefExpr>(Allocator->IgnoreParenImpCasts())->getDecl()));
   LValue AllocatorLVal = CGF.EmitLValue(Allocator->IgnoreParenImpCasts());
   AllocatorVal =

clang/test/OpenMP/target_uses_allocators.c

@@ -64,6 +64,35 @@ void fie(void) {
   {}
 }
 
+typedef enum omp_memspace_handle_t {
+  omp_default_mem_space = 0,
+  omp_large_cap_mem_space = 1,
+  omp_const_mem_space = 2,
+  omp_high_bw_mem_space = 3,
+  omp_low_lat_mem_space = 4,
+  llvm_omp_target_host_mem_space = 100,
+  llvm_omp_target_shared_mem_space = 101,
+  llvm_omp_target_device_mem_space = 102,
+  KMP_MEMSPACE_MAX_HANDLE = __UINTPTR_MAX__
+} omp_memspace_handle_t;
+
+extern omp_allocator_handle_t
+omp_init_allocator(omp_memspace_handle_t memspace, int ntraits,
+                   const omp_alloctrait_t traits[]);
+
+void *omp_aligned_alloc(unsigned long alignment, unsigned long size,
+                        omp_allocator_handle_t allocator);
+extern void * omp_alloc(int size, omp_allocator_handle_t a);
+#define N 1024
+
+void foo() {
+  int errors = 0;
+  omp_memspace_handle_t  memspace = omp_default_mem_space;
+  omp_alloctrait_t       traits[1] = {{omp_atk_alignment, 64}};
+  omp_allocator_handle_t alloc = omp_init_allocator(memspace,1,traits);
+  #pragma omp target map(tofrom: errors) uses_allocators(alloc(traits))
+  { }
+}
 #endif
 
 // CHECK: %[[#R0:]] = call i32 @__kmpc_global_thread_num(ptr @1)
@@ -140,3 +169,15 @@ void fie(void) {
 // CHECK: [[ALLOCATOR:%.+]] = load i64, ptr [[MY_ALLOCATOR_ADDR]],
 // CHECK: [[CONV:%.+]] = inttoptr i64 [[ALLOCATOR]] to ptr
 // CHECK: call void @__kmpc_destroy_allocator(i32 %{{.+}}, ptr [[CONV]])
+
+// CHECK: [[TRAITS_ADDR_REF:%.+]] = alloca ptr,
+// CHECK: [[MY_ALLOCATOR_ADDR:%alloc]] = alloca i64,
+// CHECK: [[TRAITS_ADDR:%.+]] = load ptr, ptr [[TRAITS_ADDR_REF]],
+// CHECK: [[ALLOCATOR:%.+]] = call ptr @__kmpc_init_allocator(i32 %{{.+}}, ptr null, i32 1, ptr [[TRAITS_ADDR]])
+// CHECK: [[CONV:%.+]] = ptrtoint ptr [[ALLOCATOR]] to i64
+// CHECK: store i64 [[CONV]], ptr [[MY_ALLOCATOR_ADDR]],
+
+// Destroy allocator upon exit from the region.
+// CHECK: [[ALLOCATOR:%.+]] = load i64, ptr [[MY_ALLOCATOR_ADDR]],
+// CHECK: [[CONV1:%.+]] = inttoptr i64 [[ALLOCATOR]] to ptr
+// CHECK: call void @__kmpc_destroy_allocator(i32 %{{.+}}, ptr [[CONV1]])