[OpenACC] Fix location of array-section diagnostic.

In a sub-subscript of an array-section, it is actually an array section.
So make sure we get the location correct when there isn't a 'colon' to
look at.

Author: erichkeane

clang/lib/Sema/SemaOpenACC.cpp

@@ -757,11 +757,12 @@ ExprResult SemaOpenACC::ActOnArraySectionExpr(Expr *Base, SourceLocation LBLoc,
                    !OriginalBaseTy->isConstantArrayType() &&
                    !OriginalBaseTy->isDependentSizedArrayType()))) {
     bool IsArray = !OriginalBaseTy.isNull() && OriginalBaseTy->isArrayType();
-    Diag(ColonLoc, diag::err_acc_subarray_no_length) << IsArray;
+    SourceLocation DiagLoc = ColonLoc.isInvalid() ? LBLoc : ColonLoc;
+    Diag(DiagLoc, diag::err_acc_subarray_no_length) << IsArray;
     // Fill in a dummy 'length' so that when we instantiate this we don't
     // double-diagnose here.
     ExprResult Recovery = SemaRef.CreateRecoveryExpr(
-        ColonLoc, SourceLocation(), ArrayRef<Expr *>(), Context.IntTy);
+        DiagLoc, SourceLocation(), ArrayRef<Expr *>(), Context.IntTy);
     Length = Recovery.isUsable() ? Recovery.get() : nullptr;
   }
 

clang/test/SemaOpenACC/compute-construct-copy-clause.c

@@ -69,6 +69,19 @@ void uses(int IntParam, short *PointerParam, float ArrayParam[5], Complete Compo
   // expected-error@+1{{OpenACC 'present_or_copy' clause is not valid on 'loop' directive}}
 #pragma acc loop present_or_copy(LocalInt)
   for(int i = 5; i < 10;++i);
+
+  short *ArrayOfPtrs[5];
+#pragma acc parallel copy(ArrayOfPtrs[1:1])
+  ;
+  // expected-error@+1{{OpenACC sub-array length is unspecified and cannot be inferred because the subscripted value is not an array}}
+#pragma acc parallel copy(ArrayOfPtrs[1:1][1])
+  ;
+  // expected-error@+1{{OpenACC sub-array length is unspecified and cannot be inferred because the subscripted value is not an array}}
+#pragma acc parallel copy(ArrayOfPtrs[1:1][1:])
+  ;
+#pragma acc parallel copy(ArrayOfPtrs[1:1][1:2])
+  ;
+
 }
 void ModList() {
   int V1;