diff mbox series

[4/8] OpenMP: Add inspector class to unify mapped address analysis

Message ID c211ecf94bb113acf0f1e51bd89dd483c22bb4da.1645214026.git.julian@codesourcery.com
State New
Headers show
Series OpenMP 5.0: C++ "declare mapper" support (plus struct rework, etc.) | expand

Commit Message

Julian Brown Feb. 18, 2022, 8:03 p.m. UTC 
Several places in the C and C++ front-ends dig through OpenMP addresses
from "map" clauses (etc.) in order to determine whether they are component
accesses that need "attach" operations, check duplicate mapping clauses,
and so on.  When we're extending support for more kinds of lvalues in
map clauses, it seems helpful to bring these all into one place in order
to keep all the analyses in sync, and to make it easier to reason about
which kinds of expressions are supported.

This patch introduces an "address inspector" class for that purpose,
and adjusts the C and C++ front-ends to use it.

2021-11-15  Julian Brown  <julian@codesourcery.com>

gcc/c-family/
	* c-common.h (c_omp_address_inspector): New class.
	* c-omp.c (c_omp_address_inspector::init,
	c_omp_address_inspector::analyze_components,
	c_omp_address_inspector::map_supported_p,
	c_omp_address_inspector::mappable_type): New methods.

gcc/c/
	* c-typeck.c (handle_omp_array_sections_1,
	c_finish_omp_clauses): Use c_omp_address_inspector class.

gcc/cp/
	* semantics.c (cp_omp_address_inspector): New class, derived from
	c_omp_address_inspector.
	(handle_omp_array_sections_1): Use cp_omp_address_inspector class to
	analyze OpenMP map clause expressions.  Support POINTER_PLUS_EXPR.
	(finish_omp_clauses): Likewise.  Support some additional kinds of
	lvalues in map clauses.

gcc/testsuite/
	* g++.dg/gomp/unmappable-component-1.C: New test.

Make map_supported_p strip nops

lvalue thing, generic part
---
 gcc/c-family/c-common.h                       |  44 +++
 gcc/c-family/c-omp.cc                         | 150 +++++++++++
 gcc/c/c-typeck.cc                             | 199 +++-----------
 gcc/cp/semantics.cc                           | 253 ++++++------------
 .../g++.dg/gomp/unmappable-component-1.C      |  21 ++
 libgomp/testsuite/libgomp.c++/class-array-1.C |  59 ++++
 6 files changed, 400 insertions(+), 326 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/gomp/unmappable-component-1.C
 create mode 100644 libgomp/testsuite/libgomp.c++/class-array-1.C
diff mbox series

Patch

diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index d00838a57f0..af8dc6c4e4f 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1254,6 +1254,50 @@  extern const char *c_omp_map_clause_name (tree, bool);
 extern void c_omp_adjust_map_clauses (tree, bool);
 extern tree c_omp_decompose_attachable_address (tree t, tree *virtbase);
 
+class c_omp_address_inspector
+{
+  tree clause;
+  tree orig;
+  tree deref_toplevel;
+  tree outer_virtual_base;
+  tree root_term;
+  bool component_access;
+  bool indirections;
+  int map_supported;
+
+protected:
+  virtual bool reference_ref_p (tree) { return false; }
+  virtual bool processing_template_decl_p () { return false; }
+  virtual bool mappable_type (tree t);
+  virtual void emit_unmappable_type_notes (tree) { }
+
+public:
+  c_omp_address_inspector (tree c, tree t)
+    : clause (c), orig (t), deref_toplevel (NULL_TREE),
+      outer_virtual_base (NULL_TREE), root_term (NULL_TREE),
+      component_access (false), indirections (false), map_supported (-1)
+  { }
+
+  ~c_omp_address_inspector () {}
+
+  virtual void init ();
+
+  tree analyze_components (bool);
+
+  tree get_deref_toplevel () { return deref_toplevel; }
+  tree get_outer_virtual_base () { return outer_virtual_base; }
+  tree get_root_term () { gcc_assert (root_term); return root_term; }
+  bool component_access_p () { return component_access; }
+
+  bool indir_component_ref_p ()
+    {
+      gcc_assert (!component_access || root_term != NULL_TREE);
+      return component_access && indirections;
+    }
+
+  bool map_supported_p ();
+};
+
 enum c_omp_directive_kind {
   C_OMP_DIR_STANDALONE,
   C_OMP_DIR_CONSTRUCT,
diff --git a/gcc/c-family/c-omp.cc b/gcc/c-family/c-omp.cc
index 0e76eb4392e..e3270f781b0 100644
--- a/gcc/c-family/c-omp.cc
+++ b/gcc/c-family/c-omp.cc
@@ -3113,6 +3113,156 @@  c_omp_adjust_map_clauses (tree clauses, bool is_target)
     }
 }
 
+/* This could just be done in the constructor, but we need to call the
+   subclass's version of reference_ref_p, etc.  */
+
+void
+c_omp_address_inspector::init ()
+{
+  tree t = orig;
+
+  gcc_assert (TREE_CODE (t) != ARRAY_REF);
+
+  /* We may have a reference-typed component access at the outermost level
+     that has had convert_from_reference called on it.  Look through that
+     access.  */
+  if (reference_ref_p (t)
+      && TREE_CODE (TREE_OPERAND (t, 0)) == COMPONENT_REF)
+    {
+      t = TREE_OPERAND (t, 0);
+      deref_toplevel = t;
+    }
+  else
+    deref_toplevel = t;
+
+  /* Strip off expression nodes that may enclose a COMPONENT_REF.  Look through
+     references, but not indirections through pointers.  */
+  while (1)
+    {
+      if (TREE_CODE (t) == COMPOUND_EXPR)
+	{
+	  t = TREE_OPERAND (t, 1);
+	  STRIP_NOPS (t);
+	}
+      else if (TREE_CODE (t) == POINTER_PLUS_EXPR
+	       || TREE_CODE (t) == SAVE_EXPR)
+	t = TREE_OPERAND (t, 0);
+      else if (reference_ref_p (t))
+	t = TREE_OPERAND (t, 0);
+      else
+	break;
+    }
+
+  outer_virtual_base = t;
+
+  if (TREE_CODE (t) == COMPONENT_REF)
+    component_access = true;
+}
+
+tree
+c_omp_address_inspector::analyze_components (bool checking)
+{
+  if (root_term)
+    return root_term;
+
+  gcc_assert (TREE_CODE (outer_virtual_base) == COMPONENT_REF);
+
+  tree t = outer_virtual_base;
+
+  if (checking
+      && TREE_CODE (TREE_OPERAND (t, 1)) == FIELD_DECL
+      && DECL_BIT_FIELD (TREE_OPERAND (t, 1)))
+    {
+      error_at (OMP_CLAUSE_LOCATION (clause),
+		"bit-field %qE in %qs clause",
+		t, omp_clause_code_name[OMP_CLAUSE_CODE (clause)]);
+      return error_mark_node;
+    }
+  else if (checking
+	   && !processing_template_decl_p ()
+	   && !mappable_type (TREE_TYPE (t)))
+    {
+      error_at (OMP_CLAUSE_LOCATION (clause),
+		"%qE does not have a mappable type in %qs clause",
+		t, omp_clause_code_name[OMP_CLAUSE_CODE (clause)]);
+      emit_unmappable_type_notes (TREE_TYPE (t));
+      return error_mark_node;
+    }
+  else if (checking && TREE_TYPE (t) && TYPE_ATOMIC (TREE_TYPE (t)))
+    {
+      error_at (OMP_CLAUSE_LOCATION (clause),
+		"%<_Atomic%> %qE in %qs clause", t,
+		omp_clause_code_name[OMP_CLAUSE_CODE (clause)]);
+      return error_mark_node;
+    }
+
+  while (TREE_CODE (t) == COMPONENT_REF)
+    {
+      if (checking
+	  && TREE_TYPE (TREE_OPERAND (t, 0))
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == UNION_TYPE)
+	{
+	  error_at (OMP_CLAUSE_LOCATION (clause),
+		    "%qE is a member of a union", t);
+	  return error_mark_node;
+	}
+      t = TREE_OPERAND (t, 0);
+      while (TREE_CODE (t) == MEM_REF
+	     || TREE_CODE (t) == INDIRECT_REF
+	     || TREE_CODE (t) == ARRAY_REF)
+	{
+	  if (TREE_CODE (t) == MEM_REF
+	      || TREE_CODE (t) == INDIRECT_REF)
+	    indirections = true;
+	  t = TREE_OPERAND (t, 0);
+	  STRIP_NOPS (t);
+	  if (TREE_CODE (t) == POINTER_PLUS_EXPR)
+	    t = TREE_OPERAND (t, 0);
+	}
+    }
+
+  root_term = t;
+
+  return t;
+}
+
+bool
+c_omp_address_inspector::map_supported_p ()
+{
+  /* If we've already decided if the mapped address is supported, return
+     that.  */
+  if (map_supported != -1)
+    return map_supported;
+
+  /* Get the innermost point recorded so far.  */
+  tree t = root_term ? root_term : outer_virtual_base;
+
+  STRIP_NOPS (t);
+
+  while (TREE_CODE (t) == INDIRECT_REF
+	 || TREE_CODE (t) == MEM_REF
+	 || TREE_CODE (t) == ARRAY_REF
+	 || TREE_CODE (t) == COMPONENT_REF
+	 || TREE_CODE (t) == COMPOUND_EXPR
+	 || TREE_CODE (t) == SAVE_EXPR
+	 || TREE_CODE (t) == POINTER_PLUS_EXPR
+	 || TREE_CODE (t) == NON_LVALUE_EXPR)
+    if (TREE_CODE (t) == COMPOUND_EXPR)
+      t = TREE_OPERAND (t, 1);
+    else
+      t = TREE_OPERAND (t, 0);
+
+  map_supported = DECL_P (t);
+
+  return map_supported;
+}
+
+bool
+c_omp_address_inspector::mappable_type (tree t)
+{
+  return lang_hooks.types.omp_mappable_type (t);
+}
+
 tree
 c_omp_decompose_attachable_address (tree t, tree *virtbase)
 {
diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 70875a52ae0..7a8cdf16e1e 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -13212,6 +13212,8 @@  handle_omp_array_sections_1 (tree c, tree t, vec<tree> &types,
     {
       if (error_operand_p (t))
 	return error_mark_node;
+      c_omp_address_inspector t_insp (c, t);
+      t_insp.init ();
       ret = t;
       if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_AFFINITY
 	  && OMP_CLAUSE_CODE (c) != OMP_CLAUSE_DEPEND
@@ -13221,59 +13223,15 @@  handle_omp_array_sections_1 (tree c, tree t, vec<tree> &types,
 		    t, omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
 	  return error_mark_node;
 	}
-      while (TREE_CODE (t) == INDIRECT_REF)
-	{
-	  t = TREE_OPERAND (t, 0);
-	  STRIP_NOPS (t);
-	  if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-	    t = TREE_OPERAND (t, 0);
-	}
-      while (TREE_CODE (t) == COMPOUND_EXPR)
-	{
-	  t = TREE_OPERAND (t, 1);
-	  STRIP_NOPS (t);
-	}
-      if (TREE_CODE (t) == COMPONENT_REF
+      if (t_insp.component_access_p ()
 	  && (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
 	      || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_TO
 	      || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FROM))
-	{
-	  if (DECL_BIT_FIELD (TREE_OPERAND (t, 1)))
-	    {
-	      error_at (OMP_CLAUSE_LOCATION (c),
-			"bit-field %qE in %qs clause",
-			t, omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-	      return error_mark_node;
-	    }
-	  while (TREE_CODE (t) == COMPONENT_REF)
-	    {
-	      if (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == UNION_TYPE)
-		{
-		  error_at (OMP_CLAUSE_LOCATION (c),
-			    "%qE is a member of a union", t);
-		  return error_mark_node;
-		}
-	      t = TREE_OPERAND (t, 0);
-	      while (TREE_CODE (t) == MEM_REF
-		     || TREE_CODE (t) == INDIRECT_REF
-		     || TREE_CODE (t) == ARRAY_REF)
-		{
-		  t = TREE_OPERAND (t, 0);
-		  STRIP_NOPS (t);
-		  if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-		    t = TREE_OPERAND (t, 0);
-		}
-	      if (ort == C_ORT_ACC && TREE_CODE (t) == MEM_REF)
-		{
-		  if (maybe_ne (mem_ref_offset (t), 0))
-		    error_at (OMP_CLAUSE_LOCATION (c),
-			      "cannot dereference %qE in %qs clause", t,
-			      omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		  else
-		    t = TREE_OPERAND (t, 0);
-		}
-	    }
-	}
+	t = t_insp.analyze_components (true);
+      else
+	t = t_insp.get_outer_virtual_base ();
+      if (t == error_mark_node)
+	return error_mark_node;
       if (!VAR_P (t) && TREE_CODE (t) != PARM_DECL)
 	{
 	  if (DECL_P (t))
@@ -14920,24 +14878,16 @@  c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		    }
 		  while (TREE_CODE (t) == ARRAY_REF)
 		    t = TREE_OPERAND (t, 0);
-		  if (TREE_CODE (t) == COMPONENT_REF
-		      && TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE)
+
+		  c_omp_address_inspector t_insp (c, t);
+		  t_insp.init ();
+
+		  tree ovb = t_insp.get_outer_virtual_base ();
+
+		  if (TREE_CODE (ovb) == COMPONENT_REF
+		      && TREE_CODE (TREE_TYPE (ovb)) == ARRAY_TYPE)
 		    {
-		      do
-			{
-			  t = TREE_OPERAND (t, 0);
-			  if (TREE_CODE (t) == MEM_REF
-			      || TREE_CODE (t) == INDIRECT_REF
-			      || TREE_CODE (t) == ARRAY_REF)
-			    {
-			      t = TREE_OPERAND (t, 0);
-			      STRIP_NOPS (t);
-			      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-				t = TREE_OPERAND (t, 0);
-			    }
-			}
-		      while (TREE_CODE (t) == COMPONENT_REF
-			     || TREE_CODE (t) == ARRAY_REF);
+		      t = t_insp.analyze_components (false);
 
 		      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
 			  && OMP_CLAUSE_MAP_IMPLICIT (c)
@@ -15005,96 +14955,35 @@  c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	       bias) to zero here, so it is not set erroneously to the pointer
 	       size later on in gimplify.cc.  */
 	    OMP_CLAUSE_SIZE (c) = size_zero_node;
-	  while (TREE_CODE (t) == INDIRECT_REF
-		 || TREE_CODE (t) == ARRAY_REF)
-	    {
-	      t = TREE_OPERAND (t, 0);
-	      STRIP_NOPS (t);
-	      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-		t = TREE_OPERAND (t, 0);
-	    }
-	  while (TREE_CODE (t) == COMPOUND_EXPR)
-	    {
-	      t = TREE_OPERAND (t, 1);
-	      STRIP_NOPS (t);
-	    }
-	  indir_component_ref_p = false;
-	  if (TREE_CODE (t) == COMPONENT_REF
-	      && (TREE_CODE (TREE_OPERAND (t, 0)) == MEM_REF
-		  || TREE_CODE (TREE_OPERAND (t, 0)) == INDIRECT_REF
-		  || TREE_CODE (TREE_OPERAND (t, 0)) == ARRAY_REF))
-	    {
-	      t = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
-	      indir_component_ref_p = true;
-	      STRIP_NOPS (t);
-	      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-		t = TREE_OPERAND (t, 0);
-	    }
 
-	  if (TREE_CODE (t) == COMPONENT_REF
-	      && OMP_CLAUSE_CODE (c) != OMP_CLAUSE__CACHE_)
-	    {
-	      if (DECL_BIT_FIELD (TREE_OPERAND (t, 1)))
-		{
-		  error_at (OMP_CLAUSE_LOCATION (c),
-			    "bit-field %qE in %qs clause",
-			    t, omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		  remove = true;
-		}
-	      else if (!lang_hooks.types.omp_mappable_type (TREE_TYPE (t)))
-		{
-		  error_at (OMP_CLAUSE_LOCATION (c),
-			    "%qE does not have a mappable type in %qs clause",
-			    t, omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		  remove = true;
-		}
-	      else if (TYPE_ATOMIC (TREE_TYPE (t)))
-		{
-		  error_at (OMP_CLAUSE_LOCATION (c),
-			    "%<_Atomic%> %qE in %qs clause", t,
-			    omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		  remove = true;
-		}
-	      while (TREE_CODE (t) == COMPONENT_REF)
-		{
-		  if (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0)))
-		      == UNION_TYPE)
-		    {
-		      error_at (OMP_CLAUSE_LOCATION (c),
-				"%qE is a member of a union", t);
-		      remove = true;
-		      break;
-		    }
-		  t = TREE_OPERAND (t, 0);
-		  if (TREE_CODE (t) == MEM_REF)
-		    {
-		      if (maybe_ne (mem_ref_offset (t), 0))
-			error_at (OMP_CLAUSE_LOCATION (c),
-				  "cannot dereference %qE in %qs clause", t,
-				  omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		      else
-			t = TREE_OPERAND (t, 0);
-		    }
-		  while (TREE_CODE (t) == MEM_REF
-			 || TREE_CODE (t) == INDIRECT_REF
-			 || TREE_CODE (t) == ARRAY_REF)
-		    {
-		      t = TREE_OPERAND (t, 0);
-		      STRIP_NOPS (t);
-		      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-			t = TREE_OPERAND (t, 0);
-		    }
-		}
-	      if (remove)
+	  {
+	    c_omp_address_inspector t_insp (c, t);
+	    t_insp.init ();
+
+	    if (t_insp.component_access_p ()
+		&& OMP_CLAUSE_CODE (c) != OMP_CLAUSE__CACHE_)
+	      t = t_insp.analyze_components (true);
+	    else
+	      t = t_insp.get_outer_virtual_base ();
+
+	    if (t == error_mark_node)
+	      {
+		remove = true;
 		break;
-	      if (VAR_P (t) || TREE_CODE (t) == PARM_DECL)
-		{
-		  if (bitmap_bit_p (&map_field_head, DECL_UID (t))
-		      || (ort != C_ORT_ACC
-			  && bitmap_bit_p (&map_head, DECL_UID (t))))
-		    break;
-		}
-	    }
+	      }
+
+	    indir_component_ref_p = t_insp.indir_component_ref_p ();
+
+	    if (t_insp.component_access_p ()
+		&& (VAR_P (t) || TREE_CODE (t) == PARM_DECL))
+	      {
+		if (bitmap_bit_p (&map_field_head, DECL_UID (t))
+		    || (ort != C_ORT_ACC
+			&& bitmap_bit_p (&map_head, DECL_UID (t))))
+		  break;
+	      }
+	  }
+
 	  if (!VAR_P (t) && TREE_CODE (t) != PARM_DECL)
 	    {
 	      error_at (OMP_CLAUSE_LOCATION (c),
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 5f034bc8a09..abc0ba3e0ff 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -5026,6 +5026,39 @@  omp_privatize_field (tree t, bool shared)
   return v;
 }
 
+/* C++ specialisation of the c_omp_address_inspector class.  */
+
+class cp_omp_address_inspector : public c_omp_address_inspector
+{
+protected:
+  bool reference_ref_p (tree t)
+  {
+    return REFERENCE_REF_P (t);
+  }
+
+  bool processing_template_decl_p ()
+  {
+    return processing_template_decl;
+  }
+
+  bool mappable_type (tree t)
+  {
+    return cp_omp_mappable_type (t);
+  }
+
+  void emit_unmappable_type_notes (tree t)
+  {
+    cp_omp_emit_unmappable_type_notes (t);
+  }
+
+public:
+  cp_omp_address_inspector (tree c, tree t) : c_omp_address_inspector (c, t)
+  { }
+
+  ~cp_omp_address_inspector ()
+  { }
+};
+
 /* Helper function for handle_omp_array_sections.  Called recursively
    to handle multiple array-section-subscripts.  C is the clause,
    T current expression (initially OMP_CLAUSE_DECL), which is either
@@ -5056,59 +5089,18 @@  handle_omp_array_sections_1 (tree c, tree t, vec<tree> &types,
     {
       if (error_operand_p (t))
 	return error_mark_node;
-      if (REFERENCE_REF_P (t)
-	  && TREE_CODE (TREE_OPERAND (t, 0)) == COMPONENT_REF)
-	t = TREE_OPERAND (t, 0);
-      ret = t;
-      while (TREE_CODE (t) == INDIRECT_REF)
-	{
-	  t = TREE_OPERAND (t, 0);
-	  STRIP_NOPS (t);
-	  if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-	    t = TREE_OPERAND (t, 0);
-	}
-      while (TREE_CODE (t) == COMPOUND_EXPR)
-	{
-	  t = TREE_OPERAND (t, 1);
-	  STRIP_NOPS (t);
-	}
-      if (TREE_CODE (t) == COMPONENT_REF
+      cp_omp_address_inspector t_insp (c, t);
+      t_insp.init ();
+      if (t_insp.component_access_p ()
 	  && (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
 	      || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_TO
-	      || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FROM)
-	  && !type_dependent_expression_p (t))
-	{
-	  if (TREE_CODE (TREE_OPERAND (t, 1)) == FIELD_DECL
-	      && DECL_BIT_FIELD (TREE_OPERAND (t, 1)))
-	    {
-	      error_at (OMP_CLAUSE_LOCATION (c),
-			"bit-field %qE in %qs clause",
-			t, omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-	      return error_mark_node;
-	    }
-	  while (TREE_CODE (t) == COMPONENT_REF)
-	    {
-	      if (TREE_TYPE (TREE_OPERAND (t, 0))
-		  && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == UNION_TYPE)
-		{
-		  error_at (OMP_CLAUSE_LOCATION (c),
-			    "%qE is a member of a union", t);
-		  return error_mark_node;
-		}
-	      t = TREE_OPERAND (t, 0);
-	      while (TREE_CODE (t) == MEM_REF
-		     || TREE_CODE (t) == INDIRECT_REF
-		     || TREE_CODE (t) == ARRAY_REF)
-		{
-		  t = TREE_OPERAND (t, 0);
-		  STRIP_NOPS (t);
-		  if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-		    t = TREE_OPERAND (t, 0);
-		}
-	    }
-	  if (REFERENCE_REF_P (t))
-	    t = TREE_OPERAND (t, 0);
-	}
+	      || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FROM))
+	t = t_insp.analyze_components (true);
+      else
+	t = t_insp.get_outer_virtual_base ();
+      if (t == error_mark_node)
+	return error_mark_node;
+      ret = t_insp.get_deref_toplevel ();
       if (TREE_CODE (t) == FIELD_DECL)
 	ret = finish_non_static_data_member (t, NULL_TREE, NULL_TREE);
       else if (!VAR_P (t) && TREE_CODE (t) != PARM_DECL)
@@ -7937,28 +7929,15 @@  finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		    }
 		  while (TREE_CODE (t) == ARRAY_REF)
 		    t = TREE_OPERAND (t, 0);
-		  if (TREE_CODE (t) == COMPONENT_REF
-		      && TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE)
+
+		  cp_omp_address_inspector t_insp (c, t);
+		  t_insp.init ();
+		  tree ovb = t_insp.get_outer_virtual_base ();
+
+		  if (TREE_CODE (ovb) == COMPONENT_REF
+		      && TREE_CODE (TREE_TYPE (ovb)) == ARRAY_TYPE)
 		    {
-		      do
-			{
-			  t = TREE_OPERAND (t, 0);
-			  if (REFERENCE_REF_P (t))
-			    t = TREE_OPERAND (t, 0);
-			  if (TREE_CODE (t) == MEM_REF
-			      || TREE_CODE (t) == INDIRECT_REF
-			      || TREE_CODE (t) == ARRAY_REF)
-			    {
-			      t = TREE_OPERAND (t, 0);
-			      STRIP_NOPS (t);
-			      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-				t = TREE_OPERAND (t, 0);
-			      if (REFERENCE_REF_P (t))
-				t = TREE_OPERAND (t, 0);
-			    }
-			}
-		      while (TREE_CODE (t) == COMPONENT_REF
-			     || TREE_CODE (t) == ARRAY_REF);
+		      t = t_insp.analyze_components (false);
 
 		      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
 			  && OMP_CLAUSE_MAP_IMPLICIT (c)
@@ -8026,106 +8005,38 @@  finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	       bias) to zero here, so it is not set erroneously to the pointer
 	       size later on in gimplify.cc.  */
 	    OMP_CLAUSE_SIZE (c) = size_zero_node;
-	  if (REFERENCE_REF_P (t)
-	      && TREE_CODE (TREE_OPERAND (t, 0)) == COMPONENT_REF)
-	    {
-	      t = TREE_OPERAND (t, 0);
-	      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
-		  && OMP_CLAUSE_MAP_KIND (c) != GOMP_MAP_ATTACH_DETACH)
-		OMP_CLAUSE_DECL (c) = t;
-	    }
-	  while (TREE_CODE (t) == INDIRECT_REF
-		 || TREE_CODE (t) == ARRAY_REF)
-	    {
-	      t = TREE_OPERAND (t, 0);
-	      STRIP_NOPS (t);
-	      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-		t = TREE_OPERAND (t, 0);
-	    }
-	  while (TREE_CODE (t) == COMPOUND_EXPR)
-	    {
-	      t = TREE_OPERAND (t, 1);
-	      STRIP_NOPS (t);
-	    }
-	  indir_component_ref_p = false;
-	  if (TREE_CODE (t) == COMPONENT_REF
-	      && (TREE_CODE (TREE_OPERAND (t, 0)) == INDIRECT_REF
-		  || TREE_CODE (TREE_OPERAND (t, 0)) == ARRAY_REF))
-	    {
-	      t = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
-	      indir_component_ref_p = true;
-	      if (REFERENCE_REF_P (t))
-		t = TREE_OPERAND (t, 0);
-	      STRIP_NOPS (t);
-	      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-		t = TREE_OPERAND (t, 0);
-	    }
-	  if (TREE_CODE (t) == COMPONENT_REF
-	      && OMP_CLAUSE_CODE (c) != OMP_CLAUSE__CACHE_)
-	    {
-	      if (type_dependent_expression_p (t))
+
+	  {
+	    cp_omp_address_inspector t_insp (c, t);
+	    t_insp.init ();
+
+	    if (t_insp.component_access_p ()
+		&& OMP_CLAUSE_CODE (c) != OMP_CLAUSE__CACHE_)
+	      t = t_insp.analyze_components (true);
+	    else
+	      t = t_insp.get_outer_virtual_base ();
+	    if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
+		&& OMP_CLAUSE_MAP_KIND (c) != GOMP_MAP_ATTACH_DETACH)
+	      OMP_CLAUSE_DECL (c) = t_insp.get_deref_toplevel ();
+	    if (type_dependent_expression_p (t_insp.get_deref_toplevel ()))
+	      break;
+	    if (t == error_mark_node)
+	      {
+		remove = true;
 		break;
-	      if (TREE_CODE (TREE_OPERAND (t, 1)) == FIELD_DECL
-		  && DECL_BIT_FIELD (TREE_OPERAND (t, 1)))
-		{
-		  error_at (OMP_CLAUSE_LOCATION (c),
-			    "bit-field %qE in %qs clause",
-			    t, omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		  remove = true;
-		}
-	      else if (!cp_omp_mappable_type (TREE_TYPE (t)))
-		{
-		  error_at (OMP_CLAUSE_LOCATION (c),
-			    "%qE does not have a mappable type in %qs clause",
-			    t, omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		  cp_omp_emit_unmappable_type_notes (TREE_TYPE (t));
-		  remove = true;
-		}
-	      while (TREE_CODE (t) == COMPONENT_REF)
-		{
-		  if (TREE_TYPE (TREE_OPERAND (t, 0))
-		      && (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0)))
-			  == UNION_TYPE))
-		    {
-		      error_at (OMP_CLAUSE_LOCATION (c),
-				"%qE is a member of a union", t);
-		      remove = true;
-		      break;
-		    }
-		  t = TREE_OPERAND (t, 0);
-		  if (TREE_CODE (t) == MEM_REF)
-		    {
-		      if (maybe_ne (mem_ref_offset (t), 0))
-			error_at (OMP_CLAUSE_LOCATION (c),
-				  "cannot dereference %qE in %qs clause", t,
-				  omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		      else
-			t = TREE_OPERAND (t, 0);
-		    }
-		  while (TREE_CODE (t) == MEM_REF
-			 || TREE_CODE (t) == INDIRECT_REF
-			 || TREE_CODE (t) == ARRAY_REF)
-		    {
-		      t = TREE_OPERAND (t, 0);
-		      STRIP_NOPS (t);
-		      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
-			t = TREE_OPERAND (t, 0);
-		    }
-		}
-	      if (remove)
-		break;
-	      if (REFERENCE_REF_P (t))
-		t = TREE_OPERAND (t, 0);
-	      if (VAR_P (t) || TREE_CODE (t) == PARM_DECL)
-		{
-		  if (bitmap_bit_p (&map_field_head, DECL_UID (t))
-		      || (ort != C_ORT_ACC
-			  && bitmap_bit_p (&map_head, DECL_UID (t))))
-		    goto handle_map_references;
-		}
-	    }
-	  if (!processing_template_decl
-	      && TREE_CODE (t) == FIELD_DECL)
+	      }
+	    indir_component_ref_p = t_insp.indir_component_ref_p ();
+	    if (t_insp.component_access_p ()
+		&& (VAR_P (t) || TREE_CODE (t) == PARM_DECL))
+	      {
+		if (bitmap_bit_p (&map_field_head, DECL_UID (t))
+		    || (ort != C_ORT_ACC
+			&& bitmap_bit_p (&map_head, DECL_UID (t))))
+		  goto handle_map_references;
+	      }
+	  }
+
+	  if (!processing_template_decl && TREE_CODE (t) == FIELD_DECL)
 	    {
 	      OMP_CLAUSE_DECL (c) = finish_non_static_data_member (t, NULL_TREE,
 								   NULL_TREE);
diff --git a/gcc/testsuite/g++.dg/gomp/unmappable-component-1.C b/gcc/testsuite/g++.dg/gomp/unmappable-component-1.C
new file mode 100644
index 00000000000..6fbc49616b1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/gomp/unmappable-component-1.C
@@ -0,0 +1,21 @@ 
+/* { dg-do compile } */
+
+struct A {
+  static int x[10];
+};
+
+struct B {
+  A a;
+};
+
+int
+main (int argc, char *argv[])
+{
+  B *b = new B;
+#pragma omp target map(b->a) // { dg-error "'b->B::a' does not have a mappable type in 'map' clause" }
+  ;
+  B bb;
+#pragma omp target map(bb.a) // { dg-error "'bb\.B::a' does not have a mappable type in 'map' clause" }
+  ;
+  delete b;
+}
diff --git a/libgomp/testsuite/libgomp.c++/class-array-1.C b/libgomp/testsuite/libgomp.c++/class-array-1.C
new file mode 100644
index 00000000000..d8d3f7f1f99
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c++/class-array-1.C
@@ -0,0 +1,59 @@ 
+/* { dg-do run } */
+
+#include <cassert>
+
+#define N 1024
+
+class M {
+  int array[N];
+
+public:
+  M ()
+  {
+    for (int i = 0; i < N; i++)
+      array[i] = 0;
+  }
+
+  void incr_with_this (int c)
+  {
+#pragma omp target map(this->array[:N])
+    for (int i = 0; i < N; i++)
+      array[i] += c;
+  }
+
+  void incr_without_this (int c)
+  {
+#pragma omp target map(array[:N])
+    for (int i = 0; i < N; i++)
+      array[i] += c;
+  }
+
+  void incr_implicit (int c)
+  {
+#pragma omp target
+    for (int i = 0; i < N; i++)
+      array[i] += c;
+  }
+
+  void check (int c)
+  {
+    for (int i = 0; i < N; i++)
+      assert (array[i] == c);
+  }
+};
+
+int
+main (int argc, char *argv[])
+{
+  M m;
+
+  m.check (0);
+  m.incr_with_this (3);
+  m.check (3);
+  m.incr_without_this (5);
+  m.check (8);
+  m.incr_implicit (2);
+  m.check (10);
+
+  return 0;
+}