d: Fix ICE in assign_temp, at function.c:984 (PR94777)

Named arguments were being passed around by invisible reference, just
not variadic arguments.  There is a need to de-duplicate the routines
that handle declaration/parameter promotion and reference checking.
However for now, the parameter helper functions have just been renamed
to parameter_reference_p and parameter_type, to make it more clear that
it is the Parameter equivalent to declaration_reference_p and
declaration_type.

On writing the tests, a forward-reference bug was discovered on x86_64
during va_list type semantic.  This was due to fields not having their
parent set-up correctly.

gcc/d/ChangeLog:

	PR d/94777
	* d-builtins.cc (build_frontend_type): Set parent for generated
	fields of built-in types.
	* d-codegen.cc (argument_reference_p): Rename to ...
	(parameter_reference_p): ... this.
	(type_passed_as): Rename to ...
	(parameter_type): ... this.  Make TREE_ADDRESSABLE types restrict.
	(d_build_call): Move handling of non-POD types here from ...
	* d-convert.cc (convert_for_argument): ... here.
	* d-tree.h (argument_reference_p): Rename declaration to ...
	(parameter_reference_p): ... this.
	(type_passed_as): Rename declaration to ...
	(parameter_type): ... this.
	* types.cc (TypeVisitor::visit (TypeFunction *)): Update caller.

gcc/testsuite/ChangeLog:

	PR d/94777
	* gdc.dg/pr94777a.d: New test.
	* gdc.dg/pr94777b.d: New test.

9 files changed, 254 insertions, 23 deletions

diff --git a/gcc/d/ChangeLog b/gcc/d/ChangeLog
index ab3028d..3b5fc12 100644
--- a/gcc/d/ChangeLog
+++ b/gcc/d/ChangeLog
@@ -1,3 +1,20 @@
+2020-04-27  Iain Buclaw  <ibuclaw@gdcproject.org>
+
+	PR d/94777
+	* d-builtins.cc (build_frontend_type): Set parent for generated
+	fields of built-in types.
+	* d-codegen.cc (argument_reference_p): Rename to ...
+	(parameter_reference_p): ... this.
+	(type_passed_as): Rename to ...
+	(parameter_type): ... this.  Make TREE_ADDRESSABLE types restrict.
+	(d_build_call): Move handling of non-POD types here from ...
+	* d-convert.cc (convert_for_argument): ... here.
+	* d-tree.h (argument_reference_p): Rename declaration to ...
+	(parameter_reference_p): ... this.
+	(type_passed_as): Rename declaration to ...
+	(parameter_type): ... this.
+	* types.cc (TypeVisitor::visit (TypeFunction *)): Update caller.
+
 2020-04-26  Iain Buclaw  <ibuclaw@gdcproject.org>
 
 	* decl.cc (get_symbol_decl): Set DECL_DECLARED_INLINE_P or
diff --git a/gcc/d/d-builtins.cc b/gcc/d/d-builtins.cc
index cb8f43a..a5654a6 100644
--- a/gcc/d/d-builtins.cc
+++ b/gcc/d/d-builtins.cc
@@ -253,6 +253,7 @@ build_frontend_type (tree type)
 	    = Identifier::idPool (IDENTIFIER_POINTER (DECL_NAME (field)));
 	  VarDeclaration *vd = VarDeclaration::create (Loc (), ftype, fident,
 						       NULL);
+	  vd->parent = sdecl;
 	  vd->offset = tree_to_uhwi (DECL_FIELD_OFFSET (field));
 	  vd->semanticRun = PASSsemanticdone;
 	  vd->csym = field;
diff --git a/gcc/d/d-codegen.cc b/gcc/d/d-codegen.cc
index 8dc1ab2..12c6f13 100644
--- a/gcc/d/d-codegen.cc
+++ b/gcc/d/d-codegen.cc
@@ -172,7 +172,7 @@ declaration_type (Declaration *decl)
    Return TRUE if parameter ARG is a reference type.  */
 
 bool
-argument_reference_p (Parameter *arg)
+parameter_reference_p (Parameter *arg)
 {
   Type *tb = arg->type->toBasetype ();
 
@@ -186,7 +186,7 @@ argument_reference_p (Parameter *arg)
 /* Returns the real type for parameter ARG.  */
 
 tree
-type_passed_as (Parameter *arg)
+parameter_type (Parameter *arg)
 {
   /* Lazy parameters are converted to delegates.  */
   if (arg->storageClass & STClazy)
@@ -207,9 +207,18 @@ type_passed_as (Parameter *arg)
   tree type = build_ctype (arg->type);
 
   /* Parameter is passed by reference.  */
-  if (TREE_ADDRESSABLE (type) || argument_reference_p (arg))
+  if (parameter_reference_p (arg))
     return build_reference_type (type);
 
+  /* Pass non-POD structs by invisible reference.  */
+  if (TREE_ADDRESSABLE (type))
+    {
+      type = build_reference_type (type);
+      /* There are no other pointer to this temporary.  */
+      type = build_qualified_type (type, TYPE_QUAL_RESTRICT);
+    }
+
+  /* Front-end has already taken care of type promotions.  */
   return type;
 }
 
@@ -1954,6 +1963,23 @@ d_build_call (TypeFunction *tf, tree callable, tree object,
 	      targ = build2 (COMPOUND_EXPR, TREE_TYPE (t), targ, t);
 	    }
 
+	  /* Parameter is a struct passed by invisible reference.  */
+	  if (TREE_ADDRESSABLE (TREE_TYPE (targ)))
+	    {
+	      Type *t = arg->type->toBasetype ();
+	      gcc_assert (t->ty == Tstruct);
+	      StructDeclaration *sd = ((TypeStruct *) t)->sym;
+
+	      /* Nested structs also have ADDRESSABLE set, but if the type has
+		 neither a copy constructor nor a destructor available, then we
+		 need to take care of copying its value before passing it.  */
+	      if (arg->op == TOKstructliteral || (!sd->postblit && !sd->dtor))
+		targ = force_target_expr (targ);
+
+	      targ = convert (build_reference_type (TREE_TYPE (targ)),
+			      build_address (targ));
+	    }
+
 	  vec_safe_push (args, targ);
 	}
     }
diff --git a/gcc/d/d-convert.cc b/gcc/d/d-convert.cc
index 9ee149b..e2921ec 100644
--- a/gcc/d/d-convert.cc
+++ b/gcc/d/d-convert.cc
@@ -672,25 +672,10 @@ convert_for_argument (tree expr, Parameter *arg)
       if (!POINTER_TYPE_P (TREE_TYPE (expr)))
 	return build_address (expr);
     }
-  else if (argument_reference_p (arg))
+  else if (parameter_reference_p (arg))
     {
       /* Front-end shouldn't automatically take the address.  */
-      return convert (type_passed_as (arg), build_address (expr));
-    }
-  else if (TREE_ADDRESSABLE (TREE_TYPE (expr)))
-    {
-      /* Type is a struct passed by invisible reference.  */
-      Type *t = arg->type->toBasetype ();
-      gcc_assert (t->ty == Tstruct);
-      StructDeclaration *sd = ((TypeStruct *) t)->sym;
-
-      /* Nested structs also have ADDRESSABLE set, but if the type has
-	 neither a copy constructor nor a destructor available, then we
-	 need to take care of copying its value before passing it.  */
-      if (!sd->postblit && !sd->dtor)
-	expr = force_target_expr (expr);
-
-      return convert (type_passed_as (arg), build_address (expr));
+      return convert (parameter_type (arg), build_address (expr));
     }
 
   return expr;
diff --git a/gcc/d/d-tree.h b/gcc/d/d-tree.h
index 89feb9e..48587d9 100644
--- a/gcc/d/d-tree.h
+++ b/gcc/d/d-tree.h
@@ -504,8 +504,8 @@ extern tree d_decl_context (Dsymbol *);
 extern tree copy_aggregate_type (tree);
 extern bool declaration_reference_p (Declaration *);
 extern tree declaration_type (Declaration *);
-extern bool argument_reference_p (Parameter *);
-extern tree type_passed_as (Parameter *);
+extern bool parameter_reference_p (Parameter *);
+extern tree parameter_type (Parameter *);
 extern tree build_integer_cst (dinteger_t, tree = d_int_type);
 extern tree build_float_cst (const real_t &, Type *);
 extern tree d_array_length (tree);
diff --git a/gcc/d/types.cc b/gcc/d/types.cc
index f6ae574..59a90b4 100644
--- a/gcc/d/types.cc
+++ b/gcc/d/types.cc
@@ -720,7 +720,7 @@ public:
 
 	for (size_t i = 0; i < n_args; i++)
 	  {
-	    tree type = type_passed_as (Parameter::getNth (t->parameters, i));
+	    tree type = parameter_type (Parameter::getNth (t->parameters, i));
 	    fnparams = chainon (fnparams, build_tree_list (0, type));
 	  }
       }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 07fe8a6..1f412a0 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-04-27  Iain Buclaw  <ibuclaw@gdcproject.org>
+
+	PR d/94777
+	* gdc.dg/pr94777a.d: New test.
+	* gdc.dg/pr94777b.d: New test.
+
 2020-04-26  Iain Sandoe  <iain@sandoe.co.uk>
 
 	PR c++/94752
diff --git a/gcc/testsuite/gdc.dg/pr94777a.d b/gcc/testsuite/gdc.dg/pr94777a.d
new file mode 100644
index 0000000..a58fa55
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr94777a.d
@@ -0,0 +1,15 @@
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94777
+// { dg-do compile }
+
+extern void variadic(...);
+
+void f94777()
+{
+    struct S94777
+    {
+        int fld;
+        this(this) { }
+    }
+    auto var = S94777(0);
+    variadic(var, S94777(1));
+}
diff --git a/gcc/testsuite/gdc.dg/pr94777b.d b/gcc/testsuite/gdc.dg/pr94777b.d
new file mode 100644
index 0000000..a230adb
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr94777b.d
@@ -0,0 +1,181 @@
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94777
+// { dg-additional-options "-fmain -funittest" }
+// { dg-do run { target hw } }
+// { dg-skip-if "needs gcc/config.d" { ! d_runtime } }
+
+void testVariadic(T)(int nargs, ...)
+{
+    import core.stdc.stdarg;
+    foreach(i; 0 .. nargs)
+    {
+        auto arg = va_arg!T(_argptr);
+        static if (__traits(compiles, arg.value))
+        {
+            assert(arg.value == i);
+        }
+        else static if (__traits(compiles, arg[0]))
+        {
+            foreach (value; arg)
+                assert(value == i);
+        }
+        else
+        {
+            assert(arg == T.init);
+        }
+    }
+}
+
+/******************************************/
+
+struct Constructor
+{
+    static int count;
+    int value;
+    this(int v) { count++; this.value = v; }
+}
+
+unittest
+{
+    auto a0 = Constructor(0);
+    auto a1 = Constructor(1);
+    auto a2 = Constructor(2);
+    testVariadic!Constructor(3, a0, a1, a2);
+    assert(Constructor.count == 3);
+}
+
+/******************************************/
+
+struct Postblit
+{
+    static int count = 0;
+    int value;
+    this(this) { count++; }
+}
+
+unittest
+{
+    auto a0 = Postblit(0);
+    auto a1 = Postblit(1);
+    auto a2 = Postblit(2);
+    testVariadic!Postblit(3, a0, a1, a2);
+    assert(Postblit.count == 3);
+}
+
+/******************************************/
+
+struct Destructor
+{
+    static int count = 0;
+    int value;
+    ~this() { count++; }
+}
+
+unittest
+{
+    {
+        auto a0 = Destructor(0);
+        auto a1 = Destructor(1);
+        auto a2 = Destructor(2);
+        static assert(!__traits(compiles, testVariadic!Destructor(3, a0, a1, a2)));
+    }
+    assert(Destructor.count == 3);
+}
+
+/******************************************/
+
+struct CopyConstructor 
+{
+    static int count = 0;
+    int value;
+    this(int v) { this.value = v; }
+    this(ref typeof(this) other) { count++; this.value = other.value; }
+}
+
+unittest
+{
+    auto a0 = CopyConstructor(0);
+    auto a1 = CopyConstructor(1);
+    auto a2 = CopyConstructor(2);
+    testVariadic!CopyConstructor(3, a0, a1, a2);
+    // NOTE: Cpctors are not implemented yet.
+    assert(CopyConstructor.count == 0 || CopyConstructor.count == 3);
+}
+
+/******************************************/
+
+unittest
+{
+    struct Nested
+    {
+        int value;
+    }
+
+    auto a0 = Nested(0);
+    auto a1 = Nested(1);
+    auto a2 = Nested(2);
+    testVariadic!Nested(3, a0, a1, a2);
+}
+
+/******************************************/
+
+unittest
+{
+    struct Nested2
+    {
+        int value;
+    }
+
+    void testVariadic2(int nargs, ...)
+    {
+        import core.stdc.stdarg;
+        foreach(i; 0 .. nargs)
+        {
+            auto arg = va_arg!Nested2(_argptr);
+            assert(arg.value == i);
+        }
+    }
+
+    auto a0 = Nested2(0);
+    auto a1 = Nested2(1);
+    auto a2 = Nested2(2);
+    testVariadic2(3, a0, a1, a2);
+}
+
+/******************************************/
+
+struct EmptyStruct
+{
+}
+
+unittest
+{
+    auto a0 = EmptyStruct();
+    auto a1 = EmptyStruct();
+    auto a2 = EmptyStruct();
+    testVariadic!EmptyStruct(3, a0, a1, a2);
+}
+
+/******************************************/
+
+alias StaticArray = int[4];
+
+unittest
+{
+    StaticArray a0 = 0;
+    StaticArray a1 = 1;
+    StaticArray a2 = 2;
+    // XBUG: Front-end rewrites static arrays as dynamic arrays.
+    //testVariadic!StaticArray(3, a0, a1, a2);
+}
+
+/******************************************/
+
+alias EmptyArray = void[0];
+
+unittest
+{
+    auto a0 = EmptyArray.init;
+    auto a1 = EmptyArray.init;
+    auto a2 = EmptyArray.init;
+    testVariadic!EmptyArray(3, a0, a1, a2);
+}