This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: [c++] typeinfo for target types

From: Marc Glisse <marc dot glisse at inria dot fr>
To: ramrad01 at arm dot com
Cc: Richard Henderson <rth at redhat dot com>, gcc-patches <gcc-patches at gcc dot gnu dot org>, Jason Merrill <jason at redhat dot com>
Date: Thu, 24 Apr 2014 15:25:13 +0200 (CEST)
Subject: Re: [c++] typeinfo for target types
Authentication-results: sourceware.org; auth=none
References: <alpine dot DEB dot 2 dot 02 dot 1404131018180 dot 27848 at stedding dot saclay dot inria dot fr> <53580A7D dot 5070800 at redhat dot com> <alpine dot DEB dot 2 dot 10 dot 1404232103340 dot 4018 at laptop-mg dot saclay dot inria dot fr> <CAJA7tRZnUshpc37+gXO7eQUf9vZsDrSTpin1yGcrhwQR=4LMug at mail dot gmail dot com>

On Thu, 24 Apr 2014, Ramana Radhakrishnan wrote:

On Wed, Apr 23, 2014 at 8:43 PM, Marc Glisse <marc.glisse@inria.fr> wrote:

On Wed, 23 Apr 2014, Richard Henderson wrote:

On 04/13/2014 01:41 AM, Marc Glisse wrote:


Hello,

this patch generates typeinfo for target types. On x86_64, it adds these
6
lines to nm -C libsupc++.a. A follow-up patch will be needed to export
and
version those in the shared library.

+0000000000000000 V typeinfo for __float128
+0000000000000000 V typeinfo for __float128 const*
+0000000000000000 V typeinfo for __float128*
+0000000000000000 V typeinfo name for __float128
+0000000000000000 V typeinfo name for __float128 const*
+0000000000000000 V typeinfo name for __float128*

Bootstrap and testsuite on x86_64-linux-gnu (a bit of noise in
tsan/tls_race.c).

2014-04-13  Marc Glisse  <marc.glisse@inria.fr>

    PR libstdc++/43622
gcc/c-family/
    * c-common.c (registered_builtin_types): Make non-static.
    * c-common.h (registered_builtin_types): Declare.
gcc/cp/
    * rtti.c (emit_support_tinfo_1): New function, extracted from
    emit_support_tinfos.
    (emit_support_tinfos): Call it and iterate on
registered_builtin_types.


This is causing aarch64 builds to break.



If it is causing too much trouble, we could ifdef out the last 2 lines of
emit_support_tinfos and revert the libstdc++ changes (or even revert the
whole thing).

Any c++ compilation aborts at



That's surprising, the code I touched is only ever supposed to run while
compiling one file in libsupc++, if I understand correctly.

#0  fancy_abort (file=0x14195c8 "../../git-rh/gcc/cp/mangle.c", line=2303,
   function=0x1419ff8 <write_builtin_type(tree_node*)::__FUNCTION__>
   "write_builtin_type") at ../../git-rh/gcc/diagnostic.c:1190
#1  0x00000000007ce2b4 in write_builtin_type (
   type=<real_type 0x7fb1653540 __builtin_aarch64_simd_df>)
   at ../../git-rh/gcc/cp/mangle.c:2303
#2  0x00000000007cc85c in write_type (
   type=<real_type 0x7fb1653540 __builtin_aarch64_simd_df>)
   at ../../git-rh/gcc/cp/mangle.c:1969
#3  0x00000000007d4d98 in mangle_special_for_type (
   type=<real_type 0x7fb1653540 __builtin_aarch64_simd_df>,
   code=0x1419a98 "TI") at ../../git-rh/gcc/cp/mangle.c:3569
#4  0x00000000007d4dcc in mangle_typeinfo_for_type (
   type=<real_type 0x7fb1653540 __builtin_aarch64_simd_df>)
   at ../../git-rh/gcc/cp/mangle.c:3585
#5  0x000000000070618c in get_tinfo_decl (
   type=<real_type 0x7fb1653540 __builtin_aarch64_simd_df>)
   at ../../git-rh/gcc/cp/rtti.c:422
#6  0x0000000000709ff0 in emit_support_tinfo_1 (
   bltn=<real_type 0x7fb1653540 __builtin_aarch64_simd_df>)
   at ../../git-rh/gcc/cp/rtti.c:1485
#7  0x000000000070a344 in emit_support_tinfos ()
   at ../../git-rh/gcc/cp/rtti.c:1550

Presumably the backend needs to grow some mangling support for its
builtins,



aarch64 has complicated builtins... __builtin_aarch64_simd_df uses
double_aarch64_type_node which is not the same as double_type_node. I mostly
looked at the x86 backend, so I didn't notice that aarch64 registers a lot
more builtins.

but in the meantime can we do something less drastic than abort?



Sounds good, but I am not sure how exactly. We could use a separate hook
(register_builtin_type_for_typeinfo?) so back-ends have to explicitly say
they want typeinfo, but it is ugly having to register types multiple times.
We could add a parameter to the existing register_builtin_type saying
whether we want typeinfo, but that means updating all back-ends.

We could also make typeinfo_in_lib_p more strict so for REAL_TYPE it onlyreturns true for the types listed in fundamentals.

Well some of these scalar types are not really user visible which is
where I believe the problem is coming from and prima-facie I don't
think we should be inventing mangling for some of these "internal"
types.

If the types are not user-visible, it is not clear to me why they need tobe registered with the front-end...

 We could
get the mangling functions to take a parameter that says whether errors
should be fatal and skip generating the typeinfo when we can't mangle, but
there is no convenient way to communicate this mangling failure (0 bytes
written?).

Would mangling the aarch64 builtins be a lot of work? Did other platforms
break as well?


It's not a lot of work but I'd like to make sure we're doing the right
thing on both AArch32 and AArch64. So, for now can we just revert this
till the thing is sorted out.

Ok, I'll commit the attached as soon as I've checked it isn't too broken.It is not a complete revert: splitting the rtti function is still cleaner,and the int128 symbols are still there.


2014-04-24  Marc Glisse  <marc.glisse@inria.fr>

        PR libstdc++/43622
gcc/cp/
	* rtti.c (emit_support_tinfos): Do not iterate on
	registered_builtin_types (partial revert).
libstdc++/
	* config/abi/pre/gnu.ver (CXXABI_1.3.9): Remove __float128 symbols.
	* config/abi/pre/gnu-versioned-namespace.ver: Likewise.
	* config/abi/post/x86_64-linux-gnu/baseline_symbols.txt: Update.

--
Marc Glisse

Index: gcc/cp/rtti.c
===================================================================
--- gcc/cp/rtti.c	(revision 209747)
+++ gcc/cp/rtti.c	(working copy)
@@ -1539,22 +1539,20 @@ emit_support_tinfos (void)
 			/*tag_scope=*/ts_current, false);
   pop_abi_namespace ();
   if (!COMPLETE_TYPE_P (bltn_type))
     return;
   dtor = CLASSTYPE_DESTRUCTORS (bltn_type);
   if (!dtor || DECL_EXTERNAL (dtor))
     return;
   doing_runtime = 1;
   for (ix = 0; fundamentals[ix]; ix++)
     emit_support_tinfo_1 (*fundamentals[ix]);
-  for (tree t = registered_builtin_types; t; t = TREE_CHAIN (t))
-    emit_support_tinfo_1 (TREE_VALUE (t));
 }
 
 /* Finish a type info decl. DECL_PTR is a pointer to an unemitted
    tinfo decl.  Determine whether it needs emitting, and if so
    generate the initializer.  */
 
 bool
 emit_tinfo_decl (tree decl)
 {
   tree type = TREE_TYPE (DECL_NAME (decl));
Index: libstdc++-v3/config/abi/post/x86_64-linux-gnu/baseline_symbols.txt
===================================================================
--- libstdc++-v3/config/abi/post/x86_64-linux-gnu/baseline_symbols.txt	(revision 209747)
+++ libstdc++-v3/config/abi/post/x86_64-linux-gnu/baseline_symbols.txt	(working copy)
@@ -2618,21 +2618,20 @@ OBJECT:16:_ZTISt16nested_exception@@CXXA
 OBJECT:16:_ZTISt8ios_base@@GLIBCXX_3.4
 OBJECT:16:_ZTISt9exception@@GLIBCXX_3.4
 OBJECT:16:_ZTISt9time_base@@GLIBCXX_3.4
 OBJECT:16:_ZTISt9type_info@@GLIBCXX_3.4
 OBJECT:16:_ZTIa@@CXXABI_1.3
 OBJECT:16:_ZTIb@@CXXABI_1.3
 OBJECT:16:_ZTIc@@CXXABI_1.3
 OBJECT:16:_ZTId@@CXXABI_1.3
 OBJECT:16:_ZTIe@@CXXABI_1.3
 OBJECT:16:_ZTIf@@CXXABI_1.3
-OBJECT:16:_ZTIg@@CXXABI_1.3.9
 OBJECT:16:_ZTIh@@CXXABI_1.3
 OBJECT:16:_ZTIi@@CXXABI_1.3
 OBJECT:16:_ZTIj@@CXXABI_1.3
 OBJECT:16:_ZTIl@@CXXABI_1.3
 OBJECT:16:_ZTIm@@CXXABI_1.3
 OBJECT:16:_ZTIn@@CXXABI_1.3.5
 OBJECT:16:_ZTIo@@CXXABI_1.3.5
 OBJECT:16:_ZTIs@@CXXABI_1.3
 OBJECT:16:_ZTIt@@CXXABI_1.3
 OBJECT:16:_ZTIv@@CXXABI_1.3
@@ -3119,21 +3118,20 @@ OBJECT:2:_ZNSt10ctype_base5printE@@GLIBC
 OBJECT:2:_ZNSt10ctype_base5punctE@@GLIBCXX_3.4
 OBJECT:2:_ZNSt10ctype_base5spaceE@@GLIBCXX_3.4
 OBJECT:2:_ZNSt10ctype_base5upperE@@GLIBCXX_3.4
 OBJECT:2:_ZNSt10ctype_base6xdigitE@@GLIBCXX_3.4
 OBJECT:2:_ZTSa@@CXXABI_1.3
 OBJECT:2:_ZTSb@@CXXABI_1.3
 OBJECT:2:_ZTSc@@CXXABI_1.3
 OBJECT:2:_ZTSd@@CXXABI_1.3
 OBJECT:2:_ZTSe@@CXXABI_1.3
 OBJECT:2:_ZTSf@@CXXABI_1.3
-OBJECT:2:_ZTSg@@CXXABI_1.3.9
 OBJECT:2:_ZTSh@@CXXABI_1.3
 OBJECT:2:_ZTSi@@CXXABI_1.3
 OBJECT:2:_ZTSj@@CXXABI_1.3
 OBJECT:2:_ZTSl@@CXXABI_1.3
 OBJECT:2:_ZTSm@@CXXABI_1.3
 OBJECT:2:_ZTSn@@CXXABI_1.3.9
 OBJECT:2:_ZTSo@@CXXABI_1.3.9
 OBJECT:2:_ZTSs@@CXXABI_1.3
 OBJECT:2:_ZTSt@@CXXABI_1.3
 OBJECT:2:_ZTSv@@CXXABI_1.3
@@ -3153,41 +3151,39 @@ OBJECT:32:_ZTIPKDe@@CXXABI_1.3.4
 OBJECT:32:_ZTIPKDf@@CXXABI_1.3.4
 OBJECT:32:_ZTIPKDi@@CXXABI_1.3.3
 OBJECT:32:_ZTIPKDn@@CXXABI_1.3.5
 OBJECT:32:_ZTIPKDs@@CXXABI_1.3.3
 OBJECT:32:_ZTIPKa@@CXXABI_1.3
 OBJECT:32:_ZTIPKb@@CXXABI_1.3
 OBJECT:32:_ZTIPKc@@CXXABI_1.3
 OBJECT:32:_ZTIPKd@@CXXABI_1.3
 OBJECT:32:_ZTIPKe@@CXXABI_1.3
 OBJECT:32:_ZTIPKf@@CXXABI_1.3
-OBJECT:32:_ZTIPKg@@CXXABI_1.3.9
 OBJECT:32:_ZTIPKh@@CXXABI_1.3
 OBJECT:32:_ZTIPKi@@CXXABI_1.3
 OBJECT:32:_ZTIPKj@@CXXABI_1.3
 OBJECT:32:_ZTIPKl@@CXXABI_1.3
 OBJECT:32:_ZTIPKm@@CXXABI_1.3
 OBJECT:32:_ZTIPKn@@CXXABI_1.3.5
 OBJECT:32:_ZTIPKo@@CXXABI_1.3.5
 OBJECT:32:_ZTIPKs@@CXXABI_1.3
 OBJECT:32:_ZTIPKt@@CXXABI_1.3
 OBJECT:32:_ZTIPKv@@CXXABI_1.3
 OBJECT:32:_ZTIPKw@@CXXABI_1.3
 OBJECT:32:_ZTIPKx@@CXXABI_1.3
 OBJECT:32:_ZTIPKy@@CXXABI_1.3
 OBJECT:32:_ZTIPa@@CXXABI_1.3
 OBJECT:32:_ZTIPb@@CXXABI_1.3
 OBJECT:32:_ZTIPc@@CXXABI_1.3
 OBJECT:32:_ZTIPd@@CXXABI_1.3
 OBJECT:32:_ZTIPe@@CXXABI_1.3
 OBJECT:32:_ZTIPf@@CXXABI_1.3
-OBJECT:32:_ZTIPg@@CXXABI_1.3.9
 OBJECT:32:_ZTIPh@@CXXABI_1.3
 OBJECT:32:_ZTIPi@@CXXABI_1.3
 OBJECT:32:_ZTIPj@@CXXABI_1.3
 OBJECT:32:_ZTIPl@@CXXABI_1.3
 OBJECT:32:_ZTIPm@@CXXABI_1.3
 OBJECT:32:_ZTIPn@@CXXABI_1.3.5
 OBJECT:32:_ZTIPo@@CXXABI_1.3.5
 OBJECT:32:_ZTIPs@@CXXABI_1.3
 OBJECT:32:_ZTIPt@@CXXABI_1.3
 OBJECT:32:_ZTIPv@@CXXABI_1.3
@@ -3228,21 +3224,20 @@ OBJECT:39:_ZTSSt13basic_filebufIwSt11cha
 OBJECT:39:_ZTSSt13basic_fstreamIcSt11char_traitsIcEE@@GLIBCXX_3.4
 OBJECT:39:_ZTSSt13basic_fstreamIwSt11char_traitsIwEE@@GLIBCXX_3.4
 OBJECT:39:_ZTSSt13basic_istreamIwSt11char_traitsIwEE@@GLIBCXX_3.4
 OBJECT:39:_ZTSSt13basic_ostreamIwSt11char_traitsIwEE@@GLIBCXX_3.4
 OBJECT:3:_ZTSPa@@CXXABI_1.3
 OBJECT:3:_ZTSPb@@CXXABI_1.3
 OBJECT:3:_ZTSPc@@CXXABI_1.3
 OBJECT:3:_ZTSPd@@CXXABI_1.3
 OBJECT:3:_ZTSPe@@CXXABI_1.3
 OBJECT:3:_ZTSPf@@CXXABI_1.3
-OBJECT:3:_ZTSPg@@CXXABI_1.3.9
 OBJECT:3:_ZTSPh@@CXXABI_1.3
 OBJECT:3:_ZTSPi@@CXXABI_1.3
 OBJECT:3:_ZTSPj@@CXXABI_1.3
 OBJECT:3:_ZTSPl@@CXXABI_1.3
 OBJECT:3:_ZTSPm@@CXXABI_1.3
 OBJECT:3:_ZTSPn@@CXXABI_1.3.9
 OBJECT:3:_ZTSPo@@CXXABI_1.3.9
 OBJECT:3:_ZTSPs@@CXXABI_1.3
 OBJECT:3:_ZTSPt@@CXXABI_1.3
 OBJECT:3:_ZTSPv@@CXXABI_1.3
@@ -3558,21 +3553,20 @@ OBJECT:4:_ZNSt8ios_base8showbaseE@@GLIBC
 OBJECT:4:_ZNSt8ios_base9basefieldE@@GLIBCXX_3.4
 OBJECT:4:_ZNSt8ios_base9boolalphaE@@GLIBCXX_3.4
 OBJECT:4:_ZNSt8ios_base9showpointE@@GLIBCXX_3.4
 OBJECT:4:_ZNSt8ios_base9uppercaseE@@GLIBCXX_3.4
 OBJECT:4:_ZTSPKa@@CXXABI_1.3
 OBJECT:4:_ZTSPKb@@CXXABI_1.3
 OBJECT:4:_ZTSPKc@@CXXABI_1.3
 OBJECT:4:_ZTSPKd@@CXXABI_1.3
 OBJECT:4:_ZTSPKe@@CXXABI_1.3
 OBJECT:4:_ZTSPKf@@CXXABI_1.3
-OBJECT:4:_ZTSPKg@@CXXABI_1.3.9
 OBJECT:4:_ZTSPKh@@CXXABI_1.3
 OBJECT:4:_ZTSPKi@@CXXABI_1.3
 OBJECT:4:_ZTSPKj@@CXXABI_1.3
 OBJECT:4:_ZTSPKl@@CXXABI_1.3
 OBJECT:4:_ZTSPKm@@CXXABI_1.3
 OBJECT:4:_ZTSPKn@@CXXABI_1.3.9
 OBJECT:4:_ZTSPKo@@CXXABI_1.3.9
 OBJECT:4:_ZTSPKs@@CXXABI_1.3
 OBJECT:4:_ZTSPKt@@CXXABI_1.3
 OBJECT:4:_ZTSPKv@@CXXABI_1.3
Index: libstdc++-v3/config/abi/pre/gnu-versioned-namespace.ver
===================================================================
--- libstdc++-v3/config/abi/pre/gnu-versioned-namespace.ver	(revision 209747)
+++ libstdc++-v3/config/abi/pre/gnu-versioned-namespace.ver	(working copy)
@@ -314,24 +314,24 @@ CXXABI_2.0 {
     # typeinfo for decimal floating point types
     _ZTID[fde];
     _ZTIPD[fde];
     _ZTIPKD[fde];
 
     # typeinfo for decltype(nullptr)
     _ZTIDn;
     _ZTIPDn;
     _ZTIPKDn;
 
-    # typeinfo for __int128, unsigned __int128 and __float128
-    _ZTI[gno];
-    _ZTIP[gno];
-    _ZTIPK[gno];
+    # typeinfo for __int128 and unsigned __int128
+    _ZTI[no];
+    _ZTIP[no];
+    _ZTIPK[no];
 
     # virtual table
     _ZTVN10__cxxabiv117__array_type_infoE;
     _ZTVN10__cxxabiv117__class_type_infoE;
     _ZTVN10__cxxabiv116__enum_type_infoE;
     _ZTVN10__cxxabiv120__function_type_infoE;
     _ZTVN10__cxxabiv123__fundamental_type_infoE;
     _ZTVN10__cxxabiv117__pbase_type_infoE;
     _ZTVN10__cxxabiv129__pointer_to_member_type_infoE;
     _ZTVN10__cxxabiv119__pointer_type_infoE;
Index: libstdc++-v3/config/abi/pre/gnu.ver
===================================================================
--- libstdc++-v3/config/abi/pre/gnu.ver	(revision 209747)
+++ libstdc++-v3/config/abi/pre/gnu.ver	(working copy)
@@ -1579,29 +1579,24 @@ CXXABI_1.3.8 {
     _Z16__VLTRegisterSet*;
     _Z21__VLTRegisterSetDebug*;
     _Z24__VLTVerifyVtablePointer*;
     _Z29__VLTVerifyVtablePointerDebug*;
     __VLTChangePermission;
 
 } CXXABI_1.3.7;
 
 CXXABI_1.3.9 {
 
-    # typeinfo name for __int128, unsigned __int128 and __float128
-    _ZTS[gno];
-    _ZTSP[gno];
-    _ZTSPK[gno];
-
-    # typeinfo for __float128
-    _ZTIg;
-    _ZTIPg;
-    _ZTIPKg;
+    # typeinfo name for __int128 and unsigned __int128
+    _ZTS[no];
+    _ZTSP[no];
+    _ZTSPK[no];
 
 } CXXABI_1.3.8;
 
 # Symbols in the support library (libsupc++) supporting transactional memory.
 CXXABI_TM_1 {
 
   global:
     __cxa_tm_cleanup;
 
 };

Follow-Ups:
- Re: [c++] typeinfo for target types
  - From: Ramana Radhakrishnan
- Re: [c++] typeinfo for target types
  - From: Tejas Belagod

References:
- [c++] typeinfo for target types
  - From: Marc Glisse
- Re: [c++] typeinfo for target types
  - From: Richard Henderson
- Re: [c++] typeinfo for target types
  - From: Marc Glisse
- Re: [c++] typeinfo for target types
  - From: Ramana Radhakrishnan

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]