re PR c++/81197 (ICE with structured binding and lifetime-extended temporaries)

	PR c++/81197
	* cp-tree.h (cp_maybe_mangle_decomp): Declare.
	* decl.c (cp_maybe_mangle_decomp): New function.
	(cp_finish_decomp): Don't SET_DECL_ASSEMBLER_NAME here.
	* parser.c (cp_convert_range_for,
	cp_parser_decomposition_declaration): Call cp_maybe_mangle_decomp.
	* pt.c (tsubst_expr): Likewise.
	* mangle.c (find_decomp_unqualified_name): New function.
	(write_unqualified_name): Handle DECL_DECOMPOSITION_P
	where DECL_ASSEMBLER_NAME is already set.

	* g++.dg/cpp1z/decomp34.C: New test.

From-SVN: r255705

8 files changed, 115 insertions, 9 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 488b9f3..d96b679 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,16 @@
 2017-12-15  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/81197
+	* cp-tree.h (cp_maybe_mangle_decomp): Declare.
+	* decl.c (cp_maybe_mangle_decomp): New function.
+	(cp_finish_decomp): Don't SET_DECL_ASSEMBLER_NAME here.
+	* parser.c (cp_convert_range_for,
+	cp_parser_decomposition_declaration): Call cp_maybe_mangle_decomp.
+	* pt.c (tsubst_expr): Likewise.
+	* mangle.c (find_decomp_unqualified_name): New function.
+	(write_unqualified_name): Handle DECL_DECOMPOSITION_P
+	where DECL_ASSEMBLER_NAME is already set.
+
 	PR c++/80135
 	PR c++/81922
 	* typeck2.c (digest_init_r): Change nested argument type from bool to
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 05551df..f5f974d 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6149,6 +6149,7 @@ extern void start_decl_1			(tree, bool);
 extern bool check_array_initializer		(tree, tree, tree);
 extern void cp_finish_decl			(tree, tree, bool, tree, int);
 extern tree lookup_decomp_type			(tree);
+extern void cp_maybe_mangle_decomp		(tree, tree, unsigned int);
 extern void cp_finish_decomp			(tree, tree, unsigned int);
 extern int cp_complete_array_type		(tree *, tree, bool);
 extern int cp_complete_array_type_or_error	(tree *, tree, bool, tsubst_flags_t);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 5df16bb..0e6ee05 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7339,6 +7339,25 @@ lookup_decomp_type (tree v)
   return *decomp_type_table->get (v);
 }
 
+/* Mangle a decomposition declaration if needed.  Arguments like
+   in cp_finish_decomp.  */
+
+void
+cp_maybe_mangle_decomp (tree decl, tree first, unsigned int count)
+{
+  if (!processing_template_decl
+      && !error_operand_p (decl)
+      && DECL_NAMESPACE_SCOPE_P (decl))
+    {
+      auto_vec<tree, 16> v;
+      v.safe_grow (count);
+      tree d = first;
+      for (unsigned int i = 0; i < count; i++, d = DECL_CHAIN (d))
+	v[count - i - 1] = d;
+      SET_DECL_ASSEMBLER_NAME (decl, mangle_decomp (decl, v));
+    }
+}
+
 /* Finish a decomposition declaration.  DECL is the underlying declaration
    "e", FIRST is the head of a chain of decls for the individual identifiers
    chained through DECL_CHAIN in reverse order and COUNT is the number of
@@ -7612,8 +7631,6 @@ cp_finish_decomp (tree decl, tree first, unsigned int count)
 	    DECL_HAS_VALUE_EXPR_P (v[i]) = 1;
 	  }
     }
-  else if (DECL_NAMESPACE_SCOPE_P (decl))
-    SET_DECL_ASSEMBLER_NAME (decl, mangle_decomp (decl, v));
 }
 
 /* Returns a declaration for a VAR_DECL as if:
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 6d4e591..ffd2b4c 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -1247,6 +1247,51 @@ write_template_prefix (const tree node)
   add_substitution (substitution);
 }
 
+/* As the list of identifiers for the structured binding declaration
+   DECL is likely gone, try to recover the DC <source-name>+ E portion
+   from its mangled name.  Return pointer to the DC and set len to
+   the length up to and including the terminating E.  On failure
+   return NULL.  */
+
+static const char *
+find_decomp_unqualified_name (tree decl, size_t *len)
+{
+  const char *p = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
+  const char *end = p + IDENTIFIER_LENGTH (DECL_ASSEMBLER_NAME (decl));
+  bool nested = false;
+  if (strncmp (p, "_Z", 2))
+    return NULL;
+  p += 2;
+  if (!strncmp (p, "St", 2))
+    p += 2;
+  else if (*p == 'N')
+    {
+      nested = true;
+      ++p;
+      while (ISDIGIT (p[0]))
+	{
+	  char *e;
+	  long num = strtol (p, &e, 10);
+	  if (num >= 1 && num < end - e)
+	    p = e + num;
+	  else
+	    break;
+	}
+    }
+  if (strncmp (p, "DC", 2))
+    return NULL;
+  if (nested)
+    {
+      if (end[-1] != 'E')
+	return NULL;
+      --end;
+    }
+  if (end[-1] != 'E')
+    return NULL;
+  *len = end - p;
+  return p;
+}
+
 /* We don't need to handle thunks, vtables, or VTTs here.  Those are
    mangled through special entry points.
 
@@ -1291,7 +1336,17 @@ write_unqualified_name (tree decl)
     {
       found = true;
       gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
-      write_source_name (DECL_ASSEMBLER_NAME (decl));
+      const char *decomp_str = NULL;
+      size_t decomp_len = 0;
+      if (VAR_P (decl)
+	  && DECL_DECOMPOSITION_P (decl)
+	  && DECL_NAME (decl) == NULL_TREE
+	  && DECL_NAMESPACE_SCOPE_P (decl))
+	decomp_str = find_decomp_unqualified_name (decl, &decomp_len);
+      if (decomp_str)
+	write_chars (decomp_str, decomp_len);
+      else
+	write_source_name (DECL_ASSEMBLER_NAME (decl));
     }
   else if (DECL_DECLARES_FUNCTION_P (decl))
     {
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 94e87c2..e13e127 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -11940,6 +11940,9 @@ cp_convert_range_for (tree statement, tree range_decl, tree range_expr,
 				     tf_warning_or_error);
   finish_for_expr (expression, statement);
 
+  if (VAR_P (range_decl) && DECL_DECOMPOSITION_P (range_decl))
+    cp_maybe_mangle_decomp (range_decl, decomp_first_name, decomp_cnt);
+
   /* The declaration is initialized with *__begin inside the loop body.  */
   cp_finish_decl (range_decl,
 		  build_x_indirect_ref (input_location, begin, RO_UNARY_STAR,
@@ -13283,6 +13286,7 @@ cp_parser_decomposition_declaration (cp_parser *parser,
 
       if (decl != error_mark_node)
 	{
+	  cp_maybe_mangle_decomp (decl, prev, v.length ());
 	  cp_finish_decl (decl, initializer, non_constant_p, NULL_TREE,
 			  is_direct_init ? LOOKUP_NORMAL : LOOKUP_IMPLICIT);
 	  cp_finish_decomp (decl, prev, v.length ());
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 5a6a7cf..dc50f31 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -16135,19 +16135,23 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
 		    if (VAR_P (decl))
 		      const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
 				    (pattern_decl));
-		    cp_finish_decl (decl, init, const_init, NULL_TREE, 0);
 		    if (VAR_P (decl)
 			&& DECL_DECOMPOSITION_P (decl)
 			&& TREE_TYPE (pattern_decl) != error_mark_node)
 		      {
 			unsigned int cnt;
 			tree first;
-			decl = tsubst_decomp_names (decl, pattern_decl, args,
-						    complain, in_decl, &first,
-						    &cnt);
-			if (decl != error_mark_node)
-			  cp_finish_decomp (decl, first, cnt);
+			tree ndecl
+			  = tsubst_decomp_names (decl, pattern_decl, args,
+						 complain, in_decl, &first, &cnt);
+			if (ndecl != error_mark_node)
+			  cp_maybe_mangle_decomp (ndecl, first, cnt);
+			cp_finish_decl (decl, init, const_init, NULL_TREE, 0);
+			if (ndecl != error_mark_node)
+			  cp_finish_decomp (ndecl, first, cnt);
 		      }
+		    else
+		      cp_finish_decl (decl, init, const_init, NULL_TREE, 0);
 		  }
 	      }
 	  }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e1e29f1..ba86d2f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2017-12-15  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/81197
+	* g++.dg/cpp1z/decomp34.C: New test.
+
 	PR c++/80135
 	PR c++/81922
 	* g++.dg/warn/Wplacement-new-size-1.C (fBx1): Initialize nested
diff --git a/gcc/testsuite/g++.dg/cpp1z/decomp34.C b/gcc/testsuite/g++.dg/cpp1z/decomp34.C
new file mode 100644
index 0000000..c7f0b8a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/decomp34.C
@@ -0,0 +1,11 @@
+// PR c++/81197
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+struct X { int a; };
+struct Y { int b, c, d; };
+auto&& [t] = X{};	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+namespace A { namespace B { auto&& [u, v, ww] = Y{}; } }	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+
+// { dg-final { scan-assembler "_ZGRDC1tE0" } }
+// { dg-final { scan-assembler "_ZGRN1A1BDC1u1v2wwEE1" } }