re PR go/89019 (LTO and gccgo cause ICE during free_lang_data)

gcc/go:
        PR go/89019
        * go-gcc.cc (Gcc_backend::placeholder_struct_type): Mark
        placeholder structs as requiring structural equality.
        (Gcc_backend::set_placeholder_pointer_type): Propagate the
	canonical type from the desired pointer type to the placeholder
	pointer type.
gcc/testsuite/:
        * lib/go-torture.exp: Test compiling with -flto.

From-SVN: r268572

gcc/go/ChangeLog

+2019-02-05  Nikhil Benesch  <nikhil.benesch@gmail.com>
+
+        PR go/89019
+        * go-gcc.cc (Gcc_backend::placeholder_struct_type): Mark
+        placeholder structs as requiring structural equality.
+        (Gcc_backend::set_placeholder_pointer_type): Propagate the
+	canonical type from the desired pointer type to the placeholder
+	pointer type.
+
 2019-01-09  Ian Lance Taylor  <iant@golang.org>
 
 	PR go/86343

gcc/go/go-gcc.cc

@@ -1049,6 +1049,7 @@ Gcc_backend::set_placeholder_pointer_type(Btype* placeholder,
     }
   gcc_assert(TREE_CODE(tt) == POINTER_TYPE);
   TREE_TYPE(pt) = TREE_TYPE(tt);
+  TYPE_CANONICAL(pt) = TYPE_CANONICAL(tt);
   if (TYPE_NAME(pt) != NULL_TREE)
     {
       // Build the data structure gcc wants to see for a typedef.
@@ -1080,6 +1081,12 @@ Gcc_backend::placeholder_struct_type(const std::string& name,
 			     get_identifier_from_string(name),
 			     ret);
       TYPE_NAME(ret) = decl;
+
+      // The struct type that eventually replaces this placeholder will require
+      // structural equality. The placeholder must too, so that the requirement
+      // for structural equality propagates to references that are constructed
+      // before the replacement occurs.
+      SET_TYPE_STRUCTURAL_EQUALITY(ret);
     }
   return this->make_type(ret);
 }

gcc/testsuite/ChangeLog

+2019-02-05  Nikhil Benesch  <nikhil.benesch@gmail.com>
+
+        PR go/89019
+        * lib/go-torture.exp: Test compiling with -flto.
+
 2019-02-06  Joseph Myers  <joseph@codesourcery.com>
 
 	PR c/88584

gcc/testsuite/lib/go-torture.exp

@@ -34,7 +34,8 @@ if ![info exists TORTURE_OPTIONS] {
 	{ -O2 -fomit-frame-pointer -finline-functions -funroll-loops } \
 	{ -O2 -fbounds-check } \
 	{ -O3 -g } \
-	{ -Os }]
+	{ -Os } \
+	{ -flto }]
 }