[OpenMP] Remove hidden visibility for declare target variables

This patch changes the visiblity of variables declared within a declare
target directive. Variable declarations within a declare target
directive need to be externally visible to the plugin for initialization
or reading. Previously this would cause runtime errors where the named
global could not be found because it was not included in the symbol
table.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D117362

clang/lib/AST/Decl.cpp

@@ -786,6 +786,11 @@ LinkageComputer::getLVForNamespaceScopeDecl(const NamedDecl *D,
     //
     // Note that we don't want to make the variable non-external
     // because of this, but unique-external linkage suits us.
+
+    // We need variables inside OpenMP declare target directives to be visible.
+    if (OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(Var))
+      return LinkageInfo::external();
+
     if (Context.getLangOpts().CPlusPlus && !isFirstInExternCContext(Var) &&
         !IgnoreVarTypeLinkage) {
       LinkageInfo TypeLV = getLVForType(*Var->getType(), computation);
@@ -1069,6 +1074,12 @@ LinkageComputer::getLVForClassMember(const NamedDecl *D,
 
   // Finally, merge in information from the class.
   LV.mergeMaybeWithVisibility(classLV, considerClassVisibility);
+
+  // We need variables inside OpenMP declare target directives to be visible.
+  if (const VarDecl *VD = dyn_cast<VarDecl>(D))
+    if (OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD))
+      return LinkageInfo(LV.getLinkage(), DefaultVisibility, false);
+
   return LV;
 }
 

clang/test/OpenMP/declare_target_codegen.cpp

@@ -26,25 +26,26 @@
 // CHECK-NOT: define {{.*}}{{baz1|baz4|maini1|Base|virtual_}}
 // CHECK-DAG: Bake
 // CHECK-NOT: @{{hhh|ggg|fff|eee}} =
-// CHECK-DAG: @flag = hidden global i8 undef,
+// CHECK-DAG: @flag = global i8 undef,
 // CHECK-DAG: @aaa = external global i32,
-// CHECK-DAG: @bbb ={{ hidden | }}global i32 0,
+// CHECK-DAG: @bbb = global i32 0,
 // CHECK-DAG: weak constant %struct.__tgt_offload_entry { i8* bitcast (i32* @bbb to i8*),
 // CHECK-DAG: @ccc = external global i32,
-// CHECK-DAG: @ddd ={{ hidden | }}global i32 0,
+// CHECK-DAG: @ddd = global i32 0,
 // CHECK-DAG: @hhh_decl_tgt_ref_ptr = weak global i32* null
 // CHECK-DAG: @ggg_decl_tgt_ref_ptr = weak global i32* null
 // CHECK-DAG: @fff_decl_tgt_ref_ptr = weak global i32* null
 // CHECK-DAG: @eee_decl_tgt_ref_ptr = weak global i32* null
 // CHECK-DAG: @{{.*}}maini1{{.*}}aaa = internal global i64 23,
 // CHECK-DAG: @pair = {{.*}}addrspace(3) global %struct.PAIR undef
-// CHECK-DAG: @b ={{ hidden | }}global i32 15,
-// CHECK-DAG: @d ={{ hidden | }}global i32 0,
+// CHECK-DAG: @_ZN2SS3SSSE = global i32 1,
+// CHECK-DAG: @b = global i32 15,
+// CHECK-DAG: @d = global i32 0,
 // CHECK-DAG: @c = external global i32,
-// CHECK-DAG: @globals ={{ hidden | }}global %struct.S zeroinitializer,
+// CHECK-DAG: @globals = global %struct.S zeroinitializer,
 // CHECK-DAG: [[STAT:@.+stat]] = internal global %struct.S zeroinitializer,
 // CHECK-DAG: [[STAT_REF:@.+]] = internal constant %struct.S* [[STAT]]
-// CHECK-DAG: @out_decl_target ={{ hidden | }}global i32 0,
+// CHECK-DAG: @out_decl_target = global i32 0,
 // CHECK-DAG: @llvm.used = appending global [2 x i8*] [i8* bitcast (void ()* @__omp_offloading__{{.+}}_globals_l[[@LINE+84]]_ctor to i8*), i8* bitcast (void ()* @__omp_offloading__{{.+}}_stat_l[[@LINE+85]]_ctor to i8*)],
 // CHECK-DAG: @llvm.compiler.used = appending global [1 x i8*] [i8* bitcast (%struct.S** [[STAT_REF]] to i8*)],
 
@@ -283,4 +284,11 @@ void new_bar1() {
   X->emitted();
 }
 #pragma omp end declare target
+
+struct SS {
+#pragma omp declare target
+  static int SSS;
+#pragma omp end declare target
+};
+int SS::SSS = 1;
 #endif

clang/test/OpenMP/declare_target_only_one_side_compilation.cpp

@@ -57,11 +57,11 @@ static int GY;
 
 // TODO: It is odd, probably wrong, that we don't mangle all variables.
 
-// DEVICE-DAG: @G1 = hidden {{.*}}global i32 0, align 4
+// DEVICE-DAG: @G1 = {{.*}}global i32 0, align 4
 // DEVICE-DAG: @_ZL2G2 = internal {{.*}}global i32 0, align 4
-// DEVICE-DAG: @G3 = hidden {{.*}}global i32 0, align 4
+// DEVICE-DAG: @G3 = {{.*}}global i32 0, align 4
 // DEVICE-DAG: @_ZL2G4 = internal {{.*}}global i32 0, align 4
-// DEVICE-DAG: @G5 = hidden {{.*}}global i32 0, align 4
+// DEVICE-DAG: @G5 = {{.*}}global i32 0, align 4
 // DEVICE-DAG: @_ZL2G6 = internal {{.*}}global i32 0, align 4
 // DEVICE-NOT: ref
 // DEVICE-NOT: llvm.used