[libcp1] handle anon aggregates linkage-named by typedefs

[libcp1] handle anon aggregates linkage-named by typedefs

[Alexandre Oliva]

GDB has had a work-around that uses the typedef name as the name of an
anonymous class, struct or union, when introducing them through libcc1's
C++ API.  It didn't do that for enums, that remained anonymous, and GCC
warned about using types without linkage as members of types with
linkage, which enabled us to catch the shortcoming in libcc1.

Now GDB can introduce all anonymous aggregate types without a name, and
then introduce their names through typedefs, so as to get the expected
language behavior for typedef-named anonymous types.

Ok to install?  Regression-tested with GDB's gdb.compile tests in the
users/pmuldoon/c++compile branch.


Arrange for the first typedef to an anonymous type in the same context
to be used as the linkage name for the type.

for  libcc1/ChangeLog

	* libcp1plugin.cc (plugin_build_decl): Propagate typedef name to
	anonymous aggregate target type.
---
 libcc1/libcp1plugin.cc |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/libcc1/libcp1plugin.cc b/libcc1/libcp1plugin.cc
index 545f28b9..bc448a7 100644
--- a/libcc1/libcp1plugin.cc
+++ b/libcc1/libcp1plugin.cc
@@ -1494,6 +1494,25 @@ plugin_build_decl (cc1_plugin::connection *self,
 
   set_access_flags (decl, acc_flags);
 
+  /* If this is the typedef that names an otherwise anonymous type,
+     propagate the typedef name to the type.  In normal compilation,
+     this is done in grokdeclarator.  */
+  if (sym_kind == GCC_CP_SYMBOL_TYPEDEF
+      && !template_decl_p
+      && DECL_CONTEXT (decl) == TYPE_CONTEXT (sym_type)
+      && TYPE_UNNAMED_P (sym_type))
+    {
+      for (tree t = TYPE_MAIN_VARIANT (sym_type); t; t = TYPE_NEXT_VARIANT (t))
+	if (anon_aggrname_p (TYPE_IDENTIFIER (t)))
+	  TYPE_NAME (t) = decl;
+      if (TYPE_LANG_SPECIFIC (sym_type))
+	TYPE_WAS_UNNAMED (sym_type) = 1;
+      if (TYPE_LANG_SPECIFIC (sym_type) && CLASSTYPE_TEMPLATE_INFO (sym_type))
+	DECL_NAME (CLASSTYPE_TI_TEMPLATE (sym_type))
+	  = TYPE_IDENTIFIER (sym_type);
+      reset_type_linkage (sym_type);
+    }
+
   if (sym_kind != GCC_CP_SYMBOL_TYPEDEF
       && sym_kind != GCC_CP_SYMBOL_CLASS
       && sym_kind != GCC_CP_SYMBOL_UNION

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer

Re: [libcp1] handle anon aggregates linkage-named by typedefs

[Alexandre Oliva]

Ping?  https://gcc.gnu.org/ml/gcc-patches/2017-03/msg01143.html

On Mar 21, 2017, Alexandre Oliva <aoliva@redhat.com> wrote:

> for  libcc1/ChangeLog
> 	* libcp1plugin.cc (plugin_build_decl): Propagate typedef name to
> 	anonymous aggregate target type.

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer

Re: [libcp1] handle anon aggregates linkage-named by typedefs

[Jeff Law]

On 03/21/2017 05:32 PM, Alexandre Oliva wrote:
> GDB has had a work-around that uses the typedef name as the name of an
> anonymous class, struct or union, when introducing them through libcc1's
> C++ API.  It didn't do that for enums, that remained anonymous, and GCC
> warned about using types without linkage as members of types with
> linkage, which enabled us to catch the shortcoming in libcc1.
>
> Now GDB can introduce all anonymous aggregate types without a name, and
> then introduce their names through typedefs, so as to get the expected
> language behavior for typedef-named anonymous types.
>
> Ok to install?  Regression-tested with GDB's gdb.compile tests in the
> users/pmuldoon/c++compile branch.
>
>
> Arrange for the first typedef to an anonymous type in the same context
> to be used as the linkage name for the type.
>
> for  libcc1/ChangeLog
>
> 	* libcp1plugin.cc (plugin_build_decl): Propagate typedef name to
> 	anonymous aggregate target type.
Can you put some kind of pointer in the code you copied from cp/decl.c 
so that there's some chance anyone changing that code would at least go 
look at the libcpplugin.cc copy and try to DTRT.

With that.  OK for the trunk.

jeff

Re: [libcp1] handle anon aggregates linkage-named by typedefs

[Alexandre Oliva]

On Apr 10, 2017, Jeff Law <law@redhat.com> wrote:

> On 03/21/2017 05:32 PM, Alexandre Oliva wrote:
>> * libcp1plugin.cc (plugin_build_decl): Propagate typedef name to
>> anonymous aggregate target type.
> Can you put some kind of pointer in the code you copied from cp/decl.c
> so that there's some chance anyone changing that code would at least
> go look at the libcpplugin.cc copy and try to DTRT.

Well, if we're actually touching the g++ code, I'd much rather refactor
it a bit and export this chunk of code for libcc1 to use without
copying.  How's this instead?  (testing)


[libcp1] handle anon aggregates linkage-named by typedefs

Arrange for the first typedef to an anonymous type in the same context
to be used as the linkage name for the type.

for  gcc/cp/ChangeLog

	* decl.c (name_unnamed_type): Split out of...
	(grokdeclarator): ... this.
	* decl.h (name_unnamed_type): Declare.

for  libcc1/ChangeLog

	* libcp1plugin.cc (plugin_build_decl): Call name_unnamed_type.
---
 gcc/cp/decl.c          |   75 ++++++++++++++++++++++++++++--------------------
 gcc/cp/decl.h          |    1 +
 libcc1/libcp1plugin.cc |    9 ++++++
 3 files changed, 54 insertions(+), 31 deletions(-)

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 516b93c..b29945c 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -9831,6 +9831,49 @@ mark_inline_variable (tree decl)
     }
 }
 
+
+/* Assign a typedef-given name to a class or enumeration type declared
+   as anonymous at first.  This was split out of grokdeclarator
+   because it is also used in libcc1.  */
+
+void
+name_unnamed_type (tree type, tree decl)
+{
+  gcc_assert (TYPE_UNNAMED_P (type));
+
+  /* Replace the anonymous name with the real name everywhere.  */
+  for (tree t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
+    {
+      if (anon_aggrname_p (TYPE_IDENTIFIER (t)))
+	/* We do not rename the debug info representing the
+	   unnamed tagged type because the standard says in
+	   [dcl.typedef] that the naming applies only for
+	   linkage purposes.  */
+	/*debug_hooks->set_name (t, decl);*/
+	TYPE_NAME (t) = decl;
+    }
+
+  if (TYPE_LANG_SPECIFIC (type))
+    TYPE_WAS_UNNAMED (type) = 1;
+
+  /* If this is a typedef within a template class, the nested
+     type is a (non-primary) template.  The name for the
+     template needs updating as well.  */
+  if (TYPE_LANG_SPECIFIC (type) && CLASSTYPE_TEMPLATE_INFO (type))
+    DECL_NAME (CLASSTYPE_TI_TEMPLATE (type))
+      = TYPE_IDENTIFIER (type);
+
+  /* Adjust linkage now that we aren't unnamed anymore.  */
+  reset_type_linkage (type);
+
+  /* FIXME remangle member functions; member functions of a
+     type with external linkage have external linkage.  */
+
+  /* Check that our job is done, and that it would fail if we
+     attempted to do it again.  */
+  gcc_assert (!TYPE_UNNAMED_P (type));
+}
+
 /* Given declspecs and a declarator (abstract or otherwise), determine
    the name and type of the object declared and construct a DECL node
    for it.
@@ -11555,37 +11598,7 @@ grokdeclarator (const cp_declarator *declarator,
 	  && declspecs->type_definition_p
 	  && attributes_naming_typedef_ok (*attrlist)
 	  && cp_type_quals (type) == TYPE_UNQUALIFIED)
-	{
-	  tree t;
-
-	  /* Replace the anonymous name with the real name everywhere.  */
-	  for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
-	    {
-	      if (anon_aggrname_p (TYPE_IDENTIFIER (t)))
-		/* We do not rename the debug info representing the
-		   unnamed tagged type because the standard says in
-		   [dcl.typedef] that the naming applies only for
-		   linkage purposes.  */
-		/*debug_hooks->set_name (t, decl);*/
-		TYPE_NAME (t) = decl;
-  	    }
-
-	  if (TYPE_LANG_SPECIFIC (type))
-	    TYPE_WAS_UNNAMED (type) = 1;
-
-	  /* If this is a typedef within a template class, the nested
-	     type is a (non-primary) template.  The name for the
-	     template needs updating as well.  */
-	  if (TYPE_LANG_SPECIFIC (type) && CLASSTYPE_TEMPLATE_INFO (type))
-	    DECL_NAME (CLASSTYPE_TI_TEMPLATE (type))
-	      = TYPE_IDENTIFIER (type);
-
-	  /* Adjust linkage now that we aren't unnamed anymore.  */
-	  reset_type_linkage (type);
-
-	  /* FIXME remangle member functions; member functions of a
-	     type with external linkage have external linkage.  */
-	}
+	name_unnamed_type (type, decl);
 
       if (signed_p
 	  || (typedef_decl && C_TYPEDEF_EXPLICITLY_SIGNED (typedef_decl)))
diff --git a/gcc/cp/decl.h b/gcc/cp/decl.h
index 3e1d91f..d84d90c 100644
--- a/gcc/cp/decl.h
+++ b/gcc/cp/decl.h
@@ -35,6 +35,7 @@ enum decl_context
 extern tree grokdeclarator (const cp_declarator *,
 			    cp_decl_specifier_seq *,
 			    enum decl_context, int, tree*);
+extern void name_unnamed_type (tree, tree);
 
 /* States indicating how grokdeclarator() should handle declspecs marked
    with __attribute__((deprecated)).  An object declared as
diff --git a/libcc1/libcp1plugin.cc b/libcc1/libcp1plugin.cc
index 545f28b9..2464aa2 100644
--- a/libcc1/libcp1plugin.cc
+++ b/libcc1/libcp1plugin.cc
@@ -1494,6 +1494,15 @@ plugin_build_decl (cc1_plugin::connection *self,
 
   set_access_flags (decl, acc_flags);
 
+  /* If this is the typedef that names an otherwise anonymous type,
+     propagate the typedef name to the type.  In normal compilation,
+     this is done in grokdeclarator.  */
+  if (sym_kind == GCC_CP_SYMBOL_TYPEDEF
+      && !template_decl_p
+      && DECL_CONTEXT (decl) == TYPE_CONTEXT (sym_type)
+      && TYPE_UNNAMED_P (sym_type))
+    name_unnamed_type (sym_type, decl);
+
   if (sym_kind != GCC_CP_SYMBOL_TYPEDEF
       && sym_kind != GCC_CP_SYMBOL_CLASS
       && sym_kind != GCC_CP_SYMBOL_UNION


-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer

Re: [libcp1] handle anon aggregates linkage-named by typedefs

[Jeff Law]

On 04/11/2017 03:13 PM, Alexandre Oliva wrote:
> On Apr 10, 2017, Jeff Law <law@redhat.com> wrote:
>
>> On 03/21/2017 05:32 PM, Alexandre Oliva wrote:
>>> * libcp1plugin.cc (plugin_build_decl): Propagate typedef name to
>>> anonymous aggregate target type.
>> Can you put some kind of pointer in the code you copied from cp/decl.c
>> so that there's some chance anyone changing that code would at least
>> go look at the libcpplugin.cc copy and try to DTRT.
>
> Well, if we're actually touching the g++ code, I'd much rather refactor
> it a bit and export this chunk of code for libcc1 to use without
> copying.  How's this instead?  (testing)
>
>
> [libcp1] handle anon aggregates linkage-named by typedefs
>
> Arrange for the first typedef to an anonymous type in the same context
> to be used as the linkage name for the type.
>
> for  gcc/cp/ChangeLog
>
> 	* decl.c (name_unnamed_type): Split out of...
> 	(grokdeclarator): ... this.
> 	* decl.h (name_unnamed_type): Declare.
>
> for  libcc1/ChangeLog
>
> 	* libcp1plugin.cc (plugin_build_decl): Call name_unnamed_type.
OK.

jeff