[PATCH d] Committed fix for ICE in add_symbol_to_partition_1 at lto/lto-partition.c:215 (PR94920)

[PATCH d] Committed fix for ICE in add_symbol_to_partition_1 at lto/lto-partition.c:215 (PR94920)

[Iain Buclaw]

Hi,

This patch addresses two problems with TypeInfo initializer generation.

1. D array fields pointing to compiler generated data are referencing
public symbols with no unique prefix, which can lead to duplicate
definition errors in some hard to reduce cases.  To avoid name clashes,
all symbols that are generated for TypeInfo initializers now use the
assembler name of the TypeInfo decl as a prefix.

2. An ICE would occur during LTO pass because these same decls are
considered to be part of the same comdat group as the TypeInfo decl that
it's referred by, despite itself being neither marked public nor comdat.
This resulted in decls being added to the LTRANS partition out of order,
triggering an assert when add_symbol_to_partition_1 attempted to add
them again.  To remedy, TREE_PUBLIC and DECL_COMDAT are now set on all
generated symbols.

Jakub, I'll also want to backport this to the gcc-9 branch if there's no
problem with that.

Bootstrapped and tested on x86_64-linux-gnu, and committed to trunk.

Regards,
Iain.

---
gcc/d/ChangeLog:

2020-03-21  Iain Buclaw  <ibuclaw@gdcproject.org>

	PR d/94290
	* typeinfo.cc (class TypeInfoVisitor): Replace type_ field with decl_.
	(TypeInfoVisitor::TypeInfoVisitor): Set decl_.
	(TypeInfoVisitor::result): Update.
	(TypeInfoVisitor::internal_reference): New function.
	(TypeInfoVisitor::layout_string): Use internal_reference.
	(TypeInfoVisitor::visit (TypeInfoTupleDeclaration *)): Likewise.
	(layout_typeinfo): Construct TypeInfoVisitor with typeinfo decl.
	(layout_classinfo): Likewise.

---
 gcc/d/typeinfo.cc | 47 ++++++++++++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/gcc/d/typeinfo.cc b/gcc/d/typeinfo.cc
index d4f777159af..07011deaf6f 100644
--- a/gcc/d/typeinfo.cc
+++ b/gcc/d/typeinfo.cc
@@ -341,9 +341,29 @@ class TypeInfoVisitor : public Visitor
 {
   using Visitor::visit;
 
-  tree type_;
+  tree decl_;
   vec<constructor_elt, va_gc> *init_;
 
+  /* Build an internal comdat symbol for the manifest constant VALUE, so that
+     its address can be taken.  */
+
+  tree internal_reference (tree value)
+  {
+    /* Use the typeinfo decl name as a prefix for the internal symbol.  */
+    const char *prefix = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (this->decl_));
+    tree decl = build_artificial_decl (TREE_TYPE (value), value, prefix);
+
+    /* The internal pointer reference should be public, but not visible outside
+       the compilation unit.  */
+    DECL_EXTERNAL (decl) = 0;
+    TREE_PUBLIC (decl) = 1;
+    DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
+    DECL_COMDAT (decl) = 1;
+    d_pushdecl (decl);
+
+    return decl;
+  }
+
   /* Add VALUE to the constructor values list.  */
 
   void layout_field (tree value)
@@ -364,10 +384,8 @@ class TypeInfoVisitor : public Visitor
     TREE_STATIC (value) = 1;
 
     /* Taking the address, so assign the literal to a static var.  */
-    tree decl = build_artificial_decl (TREE_TYPE (value), value);
+    tree decl = this->internal_reference (value);
     TREE_READONLY (decl) = 1;
-    DECL_EXTERNAL (decl) = 0;
-    d_pushdecl (decl);
 
     value = d_array_value (build_ctype (Type::tchar->arrayOf ()),
 			   size_int (len), build_address (decl));
@@ -500,9 +518,9 @@ class TypeInfoVisitor : public Visitor
 
 
 public:
-  TypeInfoVisitor (tree type)
+  TypeInfoVisitor (tree decl)
   {
-    this->type_ = type;
+    this->decl_ = decl;
     this->init_ = NULL;
   }
 
@@ -510,7 +528,7 @@ public:
 
   tree result (void)
   {
-    return build_struct_literal (this->type_, this->init_);
+    return build_struct_literal (TREE_TYPE (this->decl_), this->init_);
   }
 
   /* Layout of TypeInfo is:
@@ -1125,19 +1143,12 @@ public:
 				build_typeinfo (d->loc, arg->type));
       }
     tree ctor = build_constructor (build_ctype (satype), elms);
-    tree decl = build_artificial_decl (TREE_TYPE (ctor), ctor);
-
-    /* The internal pointer reference should be public, but not visible outside
-       the compilation unit, as it's referencing COMDAT decls.  */
-    TREE_PUBLIC (decl) = 1;
-    DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
-    DECL_COMDAT (decl) = 1;
+    tree decl = this->internal_reference (ctor);
 
     tree length = size_int (ti->arguments->dim);
     tree ptr = build_address (decl);
     this->layout_field (d_array_value (array_type_node, length, ptr));
 
-    d_pushdecl (decl);
     rest_of_decl_compilation (decl, 1, 0);
   }
 };
@@ -1152,8 +1163,7 @@ layout_typeinfo (TypeInfoDeclaration *d)
   if (!Type::dtypeinfo)
     create_frontend_tinfo_types ();
 
-  tree type = TREE_TYPE (get_typeinfo_decl (d));
-  TypeInfoVisitor v = TypeInfoVisitor (type);
+  TypeInfoVisitor v = TypeInfoVisitor (get_typeinfo_decl (d));
   d->accept (&v);
   return v.result ();
 }
@@ -1168,8 +1178,7 @@ layout_classinfo (ClassDeclaration *cd)
     create_frontend_tinfo_types ();
 
   TypeInfoClassDeclaration *d = TypeInfoClassDeclaration::create (cd->type);
-  tree type = TREE_TYPE (get_classinfo_decl (cd));
-  TypeInfoVisitor v = TypeInfoVisitor (type);
+  TypeInfoVisitor v = TypeInfoVisitor (get_classinfo_decl (cd));
   d->accept (&v);
   return v.result ();
 }
-- 
2.20.1