GDC 11 -fno-weak-templates functionality revert

0001-Revert-d-Add-TARGET_D_TEMPLATES_ALWAYS_COMDAT.patch

From 7ed6c100f051a820922c90ba5270356a436786a1 Mon Sep 17 00:00:00 2001
From: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Date: Mon, 31 Jan 2022 08:19:02 +0200
Subject: [PATCH] Revert "d: Add TARGET_D_TEMPLATES_ALWAYS_COMDAT"

This reverts commit bda519596543e49f77914b5677693e86be5d01d0.

Revert "d: Move call to set_linkage_for_decl to declare_extern_var."

This reverts commit 5b63eb17d863ac080cf3c7df08233054b09d3747.

Revert "d: Use weak linkage for template symbols instead of gnu.linkonce (PR99914)"

This reverts commit 76a7e7e706ac4c01cead3c6514322aaad88f9a63.
---
 gcc/config/i386/winnt-d.c      |   5 --
 gcc/d/d-lang.cc                |   2 +-
 gcc/d/d-target.def             |   8 ---
 gcc/d/d-tree.h                 |  16 ++---
 gcc/d/decl.cc                  | 107 ++++++++++++---------------------
 gcc/d/gdc.texi                 |  14 ++---
 gcc/d/lang.opt                 |   6 +-
 gcc/d/modules.cc               |  20 +++---
 gcc/d/typeinfo.cc              |  12 +++-
 gcc/doc/tm.texi                |   6 --
 gcc/doc/tm.texi.in             |   2 -
 gcc/testsuite/gdc.dg/pr99914.d |   5 --
 12 files changed, 75 insertions(+), 128 deletions(-)
 delete mode 100644 gcc/testsuite/gdc.dg/pr99914.d

diff --git a/gcc/config/i386/winnt-d.c b/gcc/config/i386/winnt-d.c
index ea4cd13d0bf..b9780258549 100644
--- a/gcc/config/i386/winnt-d.c
+++ b/gcc/config/i386/winnt-d.c
@@ -78,9 +78,4 @@ winnt_d_register_target_info (void)
 #undef TARGET_D_MINFO_END_NAME
 #define TARGET_D_MINFO_END_NAME "__stop_minfo"
 
-/* Define TARGET_D_TEMPLATES_ALWAYS_COMDAT for Windows targets.  */
-
-#undef TARGET_D_TEMPLATES_ALWAYS_COMDAT
-#define TARGET_D_TEMPLATES_ALWAYS_COMDAT true
-
 struct gcc_targetdm targetdm = TARGETDM_INITIALIZER;
diff --git a/gcc/d/d-lang.cc b/gcc/d/d-lang.cc
index 3e6566a3689..16bff2d0db3 100644
--- a/gcc/d/d-lang.cc
+++ b/gcc/d/d-lang.cc
@@ -389,7 +389,7 @@ d_init (void)
     using_eh_for_cleanups ();
 
   if (!supports_one_only ())
-    flag_weak_templates = 0;
+    flag_weak = 0;
 
   /* This is the C main, not the D main.  */
   main_identifier_node = get_identifier ("main");
diff --git a/gcc/d/d-target.def b/gcc/d/d-target.def
index 67647515cf2..aa6bf55e6e6 100644
--- a/gcc/d/d-target.def
+++ b/gcc/d/d-target.def
@@ -104,13 +104,5 @@ and @var{link_windows} to @code{1} to apply @code{stdcall} to functions with\n\
  bool, (unsigned int *link_system, unsigned int *link_windows),
  hook_bool_uintp_uintp_false)
 
-/* True if instantiations are always COMDAT if they have external linkage.  */
-DEFHOOKPOD
-(d_templates_always_comdat,
- "This flag is true if instantiated functions and variables are always COMDAT\n\
-if they have external linkage.  If this flag is false, then instantiated\n\
-decls will be emitted as weak symbols.  The default is @code{false}.",
- bool, false)
-
 /* Close the 'struct gcc_targetdm' definition.  */
 HOOK_VECTOR_END (C90_EMPTY_HACK)
diff --git a/gcc/d/d-tree.h b/gcc/d/d-tree.h
index f210b8b1a6e..32b751242ee 100644
--- a/gcc/d/d-tree.h
+++ b/gcc/d/d-tree.h
@@ -59,13 +59,7 @@ typedef Array <Expression *> Expressions;
    Usage of DECL_LANG_FLAG_?:
    0: LABEL_VARIABLE_CASE (in LABEL_DECL).
       DECL_BUILT_IN_CTFE (in FUNCTION_DECL).
-   1: DECL_IN_UNITTEST_CONDITION_P (in FUNCTION_DECL).
-   2: DECL_INSTANTIATED (in FUNCTION_DECL, VAR_DECL).  */
-
-/* Language-specific tree checkers.  */
-
-#define VAR_OR_FUNCTION_DECL_CHECK(NODE) \
-  TREE_CHECK2 (NODE, VAR_DECL, FUNCTION_DECL)
+   1: DECL_IN_UNITTEST_CONDITION_P (in FUNCTION_DECL).  */
 
 /* The kinds of scopes we recognize.  */
 
@@ -394,10 +388,6 @@ lang_tree_node
 #define DECL_IN_UNITTEST_CONDITION_P(NODE) \
   (DECL_LANG_FLAG_1 (FUNCTION_DECL_CHECK (NODE)))
 
-/* True if the decl comes from a template instance.  */
-#define DECL_INSTANTIATED(NODE) \
-  (DECL_LANG_FLAG_1 (VAR_OR_FUNCTION_DECL_CHECK (NODE)))
-
 enum d_tree_index
 {
   DTI_VTABLE_ENTRY_TYPE,
@@ -633,6 +623,7 @@ extern void d_finish_decl (tree);
 extern tree make_thunk (FuncDeclaration *, int);
 extern tree start_function (FuncDeclaration *);
 extern void finish_function (tree);
+extern void mark_needed (tree);
 extern tree get_vtable_decl (ClassDeclaration *);
 extern tree build_new_class_expr (ClassReferenceExp *);
 extern tree aggregate_initializer_decl (AggregateDeclaration *);
@@ -642,7 +633,8 @@ extern tree enum_initializer_decl (EnumDeclaration *);
 extern tree build_artificial_decl (tree, tree, const char * = NULL);
 extern tree create_field_decl (tree, const char *, int, int);
 extern void build_type_decl (tree, Dsymbol *);
-extern void set_linkage_for_decl (tree);
+extern void d_comdat_linkage (tree);
+extern void d_linkonce_linkage (tree);
 
 /* In expr.cc.  */
 extern tree build_expr (Expression *, bool = false, bool = false);
diff --git a/gcc/d/decl.cc b/gcc/d/decl.cc
index a30549ce8e0..bd1c689f5f0 100644
--- a/gcc/d/decl.cc
+++ b/gcc/d/decl.cc
@@ -59,7 +59,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "symtab-thunks.h"
 
 #include "d-tree.h"
-#include "d-target.h"
 
 
 /* Return identifier for the external mangled name of DECL.  */
@@ -388,6 +387,10 @@ public:
     /* Generate static initializer.  */
     d->sinit = aggregate_initializer_decl (d);
     DECL_INITIAL (d->sinit) = layout_struct_initializer (d);
+
+    if (d->isInstantiated ())
+      d_linkonce_linkage (d->sinit);
+
     d_finish_decl (d->sinit);
 
     /* Put out the members.  There might be static constructors in the members
@@ -500,6 +503,7 @@ public:
 
     /* Generate static initializer.  */
     DECL_INITIAL (d->sinit) = layout_class_initializer (d);
+    d_linkonce_linkage (d->sinit);
     d_finish_decl (d->sinit);
 
     /* Put out the TypeInfo.  */
@@ -507,6 +511,7 @@ public:
       create_typeinfo (d->type, NULL);
 
     DECL_INITIAL (d->csym) = layout_classinfo (d);
+    d_linkonce_linkage (d->csym);
     d_finish_decl (d->csym);
 
     /* Put out the vtbl[].  */
@@ -529,6 +534,7 @@ public:
 
     DECL_INITIAL (d->vtblsym)
       = build_constructor (TREE_TYPE (d->vtblsym), elms);
+    d_comdat_linkage (d->vtblsym);
     d_finish_decl (d->vtblsym);
 
     /* Add this decl to the current binding level.  */
@@ -572,6 +578,7 @@ public:
       }
 
     DECL_INITIAL (d->csym) = layout_classinfo (d);
+    d_linkonce_linkage (d->csym);
     d_finish_decl (d->csym);
 
     /* Add this decl to the current binding level.  */
@@ -610,6 +617,10 @@ public:
 	/* Generate static initializer.  */
 	d->sinit = enum_initializer_decl (d);
 	DECL_INITIAL (d->sinit) = build_expr (tc->sym->defaultval, true);
+
+	if (d->isInstantiated ())
+	  d_linkonce_linkage (d->sinit);
+
 	d_finish_decl (d->sinit);
       }
 
@@ -1253,22 +1264,22 @@ get_symbol_decl (Declaration *decl)
 	  DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl->csym) = 1;
 	}
 
-      /* Mark compiler generated functions as artificial.  */
-      if (fd->generated)
-	DECL_ARTIFICIAL (decl->csym) = 1;
-
       /* Vector array operations are always compiler generated.  */
       if (fd->isArrayOp)
 	{
+	  TREE_PUBLIC (decl->csym) = 1;
 	  DECL_ARTIFICIAL (decl->csym) = 1;
 	  DECL_DECLARED_INLINE_P (decl->csym) = 1;
+	  d_comdat_linkage (decl->csym);
 	}
 
-      /* Ensure and require contracts are lexically nested in the function they
-	 part of, but are always publicly callable.  */
+      /* And so are ensure and require contracts.  */
       if (fd->ident == Identifier::idPool ("ensure")
 	  || fd->ident == Identifier::idPool ("require"))
-	TREE_PUBLIC (decl->csym) = 1;
+	{
+	  DECL_ARTIFICIAL (decl->csym) = 1;
+	  TREE_PUBLIC (decl->csym) = 1;
+	}
 
       if (decl->storage_class & STCfinal)
 	DECL_FINAL_P (decl->csym) = 1;
@@ -1332,8 +1343,8 @@ get_symbol_decl (Declaration *decl)
       /* The decl has not been defined -- yet.  */
       DECL_EXTERNAL (decl->csym) = 1;
 
-      DECL_INSTANTIATED (decl->csym) = (decl->isInstantiated () != NULL);
-      set_linkage_for_decl (decl->csym);
+      if (decl->isInstantiated ())
+	d_linkonce_linkage (decl->csym);
     }
 
   /* Symbol is going in thread local storage.  */
@@ -1380,8 +1391,6 @@ declare_extern_var (tree ident, tree type)
   /* The decl has not been defined -- yet.  */
   DECL_EXTERNAL (decl) = 1;
 
-  set_linkage_for_decl (decl);
-
   return decl;
 }
 
@@ -1965,8 +1974,8 @@ finish_function (tree old_context)
 /* Mark DECL, which is a VAR_DECL or FUNCTION_DECL as a symbol that
    must be emitted in this, output module.  */
 
-static void
-d_mark_needed (tree decl)
+void
+mark_needed (tree decl)
 {
   TREE_USED (decl) = 1;
 
@@ -2326,15 +2335,12 @@ d_comdat_group (tree decl)
 /* Set DECL up to have the closest approximation of "initialized common"
    linkage available.  */
 
-static void
+void
 d_comdat_linkage (tree decl)
 {
-  /* COMDAT definitions have to be public.  */
-  gcc_assert (TREE_PUBLIC (decl));
-
-  if (supports_one_only ())
+  if (flag_weak)
     make_decl_one_only (decl, d_comdat_group (decl));
-  else if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INSTANTIATED (decl))
+  else if (TREE_CODE (decl) == FUNCTION_DECL
 	   || (VAR_P (decl) && DECL_ARTIFICIAL (decl)))
     /* We can just emit function and compiler-generated variables statically;
        having multiple copies is (for the most part) only a waste of space.  */
@@ -2344,65 +2350,26 @@ d_comdat_linkage (tree decl)
     /* Fallback, cannot have multiple copies.  */
     DECL_COMMON (decl) = 1;
 
-  if (TREE_PUBLIC (decl) && DECL_INSTANTIATED (decl))
+  if (TREE_PUBLIC (decl))
     DECL_COMDAT (decl) = 1;
 }
 
-/* Set DECL up to have the closest approximation of "weak" linkage.  */
-
-static void
-d_weak_linkage (tree decl)
-{
-  /* Weak definitions have to be public.  */
-  gcc_assert (TREE_PUBLIC (decl));
-
-  /* Allow comdat linkage to be forced with the flag `-fno-weak-templates'.  */
-  if (!flag_weak_templates || !TARGET_SUPPORTS_WEAK)
-    return d_comdat_linkage (decl);
-
-  declare_weak (decl);
-}
-
-/* DECL is a FUNCTION_DECL or a VAR_DECL with static storage.  Set flags to
-   reflect the linkage that DECL will receive in the object file.  */
+/* Set DECL up to have the closest approximation of "linkonce" linkage.  */
 
 void
-set_linkage_for_decl (tree decl)
+d_linkonce_linkage (tree decl)
 {
-  gcc_assert (VAR_OR_FUNCTION_DECL_P (decl) && TREE_STATIC (decl));
-
-  /* Non-public decls keep their internal linkage. */
+  /* Weak definitions have to be public.  */
   if (!TREE_PUBLIC (decl))
     return;
 
-  /* Don't need to give private or protected symbols a special linkage.  */
-  if ((TREE_PRIVATE (decl) || TREE_PROTECTED (decl))
-      && !DECL_INSTANTIATED (decl))
-    return;
-
-  /* Functions declared as `pragma(inline, true)' can appear in multiple
-     translation units.  */
-  if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
-    return d_comdat_linkage (decl);
-
-  /* If all instantiations must go in COMDAT, give them that linkage.
-     This also applies to other extern declarations, so that it is possible
-     for them to override template declarations.  */
-  if (targetdm.d_templates_always_comdat)
-    {
-      /* Make sure that instantiations are not removed.  */
-      if (flag_weak_templates && DECL_INSTANTIATED (decl))
-	d_mark_needed (decl);
-
-      return d_comdat_linkage (decl);
-    }
+  /* Necessary to allow DECL_ONE_ONLY or DECL_WEAK functions to be inlined.  */
+  if (TREE_CODE (decl) == FUNCTION_DECL)
+    DECL_DECLARED_INLINE_P (decl) = 1;
 
-  /* Instantiated variables and functions need to be overridable by any other
-     symbol with the same name, so give them weak linkage.  */
-  if (DECL_INSTANTIATED (decl))
-    return d_weak_linkage (decl);
+  /* No weak support, fallback to COMDAT linkage.  */
+  if (!flag_weak)
+   return d_comdat_linkage (decl);
 
-  /* Compiler generated public symbols can appear in multiple contexts.  */
-  if (DECL_ARTIFICIAL (decl))
-    return d_weak_linkage (decl);
+  make_decl_one_only (decl, d_comdat_group (decl));
 }
diff --git a/gcc/d/gdc.texi b/gcc/d/gdc.texi
index 095f7ecca41..e727848895d 100644
--- a/gcc/d/gdc.texi
+++ b/gcc/d/gdc.texi
@@ -325,13 +325,13 @@ is compiled into the program.
 Turns on compilation of @code{version} code identified by @var{ident}.
 @end table
 
-@item -fno-weak-templates
-@cindex @option{-fweak-templates}
-@cindex @option{-fno-weak-templates}
-Turns off emission of declarations that can be defined in multiple objects as
-weak symbols.  The default is to emit all public symbols as weak, unless the
-target lacks support for weak symbols.  Disabling this option means that common
-symbols are instead put in COMDAT or become private.
+@item -fno-weak
+@cindex @option{-fweak}
+@cindex @option{-fno-weak}
+Turns off emission of instantiated declarations that can be defined in multiple
+objects as weak or one-only symbols.  The default is to emit all public symbols
+as weak, unless the target lacks support for weak symbols.  Disabling this
+option means that common symbols are instead put in COMDAT or become private.
 
 @end table
 
diff --git a/gcc/d/lang.opt b/gcc/d/lang.opt
index ded218fc5e3..62e9f8ecfd2 100644
--- a/gcc/d/lang.opt
+++ b/gcc/d/lang.opt
@@ -321,9 +321,9 @@ fversion=
 D Joined RejectNegative
 -fversion=<level|ident>	Compile in version code >= <level> or identified by <ident>.
 
-fweak-templates
-D Var(flag_weak_templates) Init(1)
-Emit template instantiations as weak symbols.
+fweak
+D Var(flag_weak) Init(1)
+Emit common-like symbols as weak symbols.
 
 imultilib
 D Joined Separate
diff --git a/gcc/d/modules.cc b/gcc/d/modules.cc
index 8786344d954..af69815deb9 100644
--- a/gcc/d/modules.cc
+++ b/gcc/d/modules.cc
@@ -125,7 +125,7 @@ static Module *current_module_decl;
    by both module initialization and dso handlers.  */
 
 static FuncDeclaration *
-get_internal_fn (tree ident, const Prot &prot)
+get_internal_fn (tree ident)
 {
   Module *mod = current_module_decl;
   const char *name = IDENTIFIER_POINTER (ident);
@@ -141,10 +141,9 @@ get_internal_fn (tree ident, const Prot &prot)
 
   FuncDeclaration *fd = FuncDeclaration::genCfunc (NULL, Type::tvoid,
 						   Identifier::idPool (name));
-  fd->generated = true;
   fd->loc = Loc (mod->srcfile->toChars (), 1, 0);
   fd->parent = mod;
-  fd->protection = prot;
+  fd->protection.kind = Prot::private_;
   fd->semanticRun = PASSsemantic3done;
 
   return fd;
@@ -156,7 +155,7 @@ get_internal_fn (tree ident, const Prot &prot)
 static tree
 build_internal_fn (tree ident, tree expr)
 {
-  FuncDeclaration *fd = get_internal_fn (ident, Prot (Prot::private_));
+  FuncDeclaration *fd = get_internal_fn (ident);
   tree decl = get_symbol_decl (fd);
 
   tree old_context = start_function (fd);
@@ -338,8 +337,7 @@ build_dso_cdtor_fn (bool ctor_p)
 	}
     }
    */
-  FuncDeclaration *fd = get_internal_fn (get_identifier (name),
-					 Prot (Prot::public_));
+  FuncDeclaration *fd = get_internal_fn (get_identifier (name));
   tree decl = get_symbol_decl (fd);
 
   TREE_PUBLIC (decl) = 1;
@@ -347,6 +345,8 @@ build_dso_cdtor_fn (bool ctor_p)
   DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
   DECL_VISIBILITY_SPECIFIED (decl) = 1;
 
+  d_comdat_linkage (decl);
+
   /* Start laying out the body.  */
   tree old_context = start_function (fd);
   rest_of_decl_compilation (decl, 1, 0);
@@ -443,11 +443,15 @@ register_moduleinfo (Module *decl, tree minfo)
   /* Declare dso_slot and dso_initialized.  */
   dso_slot_node = build_dso_registry_var (GDC_PREFIX ("dso_slot"),
 					  ptr_type_node);
-  d_finish_decl (dso_slot_node);
+  DECL_EXTERNAL (dso_slot_node) = 0;
+  d_comdat_linkage (dso_slot_node);
+  rest_of_decl_compilation (dso_slot_node, 1, 0);
 
   dso_initialized_node = build_dso_registry_var (GDC_PREFIX ("dso_initialized"),
 						 boolean_type_node);
-  d_finish_decl (dso_initialized_node);
+  DECL_EXTERNAL (dso_initialized_node) = 0;
+  d_comdat_linkage (dso_initialized_node);
+  rest_of_decl_compilation (dso_initialized_node, 1, 0);
 
   /* Declare dso_ctor() and dso_dtor().  */
   tree dso_ctor = build_dso_cdtor_fn (true);
diff --git a/gcc/d/typeinfo.cc b/gcc/d/typeinfo.cc
index 9d6464deb07..925c4688743 100644
--- a/gcc/d/typeinfo.cc
+++ b/gcc/d/typeinfo.cc
@@ -359,7 +359,7 @@ class TypeInfoVisitor : public Visitor
     DECL_EXTERNAL (decl) = 0;
     TREE_PUBLIC (decl) = 1;
     DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
-    set_linkage_for_decl (decl);
+    d_comdat_linkage (decl);
     d_pushdecl (decl);
 
     return decl;
@@ -1321,6 +1321,14 @@ public:
 
     DECL_CONTEXT (tid->csym) = d_decl_context (tid);
     TREE_READONLY (tid->csym) = 1;
+
+    /* Built-in typeinfo will be referenced as one-only.  */
+    gcc_assert (!tid->isInstantiated ());
+
+    if (builtin_typeinfo_p (tid->tinfo))
+      d_linkonce_linkage (tid->csym);
+    else
+      d_comdat_linkage (tid->csym);
   }
 
   void visit (TypeInfoClassDeclaration *tid)
@@ -1485,6 +1493,8 @@ get_cpp_typeinfo_decl (ClassDeclaration *decl)
     = TREE_TYPE (build_ctype (decl->type));
   TREE_READONLY (decl->cpp_type_info_ptr_sym) = 1;
 
+  d_comdat_linkage (decl->cpp_type_info_ptr_sym);
+
   /* Layout the initializer and emit the symbol.  */
   layout_cpp_typeinfo (decl);
 
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index b370bc76b25..0f24285fcbf 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -10859,12 +10859,6 @@ and @var{link_windows} to @code{1} to apply @code{stdcall} to functions with
 @code{extern(Windows)} linkage.
 @end deftypefn
 
-@deftypevr {D Target Hook} bool TARGET_D_TEMPLATES_ALWAYS_COMDAT
-This flag is true if instantiated functions and variables are always COMDAT
-if they have external linkage.  If this flag is false, then instantiated
-decls will be emitted as weak symbols.  The default is @code{false}.
-@end deftypevr
-
 @node Named Address Spaces
 @section Adding support for named address spaces
 @cindex named address spaces
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 2974dae2701..4fc3fed94be 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -7371,8 +7371,6 @@ floating-point support; they are not included in this mechanism.
 
 @hook TARGET_D_HAS_STDCALL_CONVENTION
 
-@hook TARGET_D_TEMPLATES_ALWAYS_COMDAT
-
 @node Named Address Spaces
 @section Adding support for named address spaces
 @cindex named address spaces
diff --git a/gcc/testsuite/gdc.dg/pr99914.d b/gcc/testsuite/gdc.dg/pr99914.d
deleted file mode 100644
index 689eae02136..00000000000
--- a/gcc/testsuite/gdc.dg/pr99914.d
+++ /dev/null
@@ -1,5 +0,0 @@
-// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99914
-// { dg-additional-options "-fmain" }
-// { dg-do link { target d_runtime } }
-
-extern(C) __gshared bool rt_cmdline_enabled = false;
-- 
2.32.0