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Re: [GOOGLE] Fixes for TLS wrapper and init functions in LIPO mode
- From: Teresa Johnson <tejohnson at google dot com>
- To: Xinliang David Li <davidxl at google dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 20 Mar 2015 08:15:31 -0700
- Subject: Re: [GOOGLE] Fixes for TLS wrapper and init functions in LIPO mode
- Authentication-results: sourceware.org; auth=none
- References: <CAAe5K+WnYun4Jkcq=tgjTz_iXaYeLBa8w-NLDji37zv6WSu_mg at mail dot gmail dot com> <CAAkRFZJrvb2X+s=BJpHwaCrBuzvUCNh5GAB0fGZS_VbvPOveyw at mail dot gmail dot com> <CAAe5K+WNCaD6BxTmnTp3P44jxrkyQN6Qj1ooPLU4qwMewgRu4w at mail dot gmail dot com> <CAAe5K+VqS_EtXX2pX9JE0E7kEh-+H6AzrCKN8Do9eYwTkskqJQ at mail dot gmail dot com> <CAAkRFZKC-s1TiLMOYmU3vQ3bR7=OXZLENHbz8165FA2Z1he0Cw at mail dot gmail dot com> <CAAe5K+XjXr0otnHD+Z8tWFkMMPK1s6AyMyODHFrBnmrnh2Rd7w at mail dot gmail dot com> <CAAkRFZJtd9ASuck0zEedtH=gntf8WGwPtmpH_G2PNi0fRjWEhg at mail dot gmail dot com> <CAAe5K+VgOX3vbcpvVitp8aCyWY5iMKa2ZtUrFE79cqNqZOn7Uw at mail dot gmail dot com> <CAAkRFZLOkg1JLsZuYVCecjNMPZu7-zFUnukYd2psor_+a3nKZw at mail dot gmail dot com>
On Thu, Mar 19, 2015 at 10:38 PM, Xinliang David Li <davidxl@google.com> wrote:
> On Thu, Mar 19, 2015 at 9:57 PM, Teresa Johnson <tejohnson@google.com> wrote:
>> On Thu, Mar 19, 2015 at 8:00 PM, Xinliang David Li <davidxl@google.com> wrote:
>>> ok -- then there is an over assertion in get_local_tls_init_fn. The
>>> method can be called for aux module -- the decl created will also be
>>> promoted.
>>
>> No, it won't ever be called for an aux module. Both callsites are
>> guarded (handle_tls_init has an early return at the top, and the
>> callsite is guarded in get_tls_iniit_fn).
>>
>>>
>>> Also can we rely on late promotion (special case of artificial
>>> function __tls_init? This can avoid duplicated logic here.
>>
>> We don't need to promote __tls_init, but rather the init functions for
>> each TLS variable (which are each aliased to __tls_init).
>
>> I thought
>> about both approaches, but promoting it as it was created seemed more
>> straightforward. I can give that approach a try though if you prefer
>> it (special casing DECL_ARTIFICIAL functions that start with _ZTH).
>> Incidentally they are not marked static, so that would also need to be
>> done to get them promoted.
>
> For public tls symbols in aux module, tls wrappers will reference
> _ZTHxx init functions which are aliases to __tls_init. If __tls_init
> is not created for aux modules, what symbol will those _ZTHxx
> funcitons aliased to?
>
> Is it better just let _tls_init function to be created as usual, but
> let the standard promotion kick in later? The ZTHxx functions can
> still be marked as alias to the promoted __tls_init?
So there are 3 function decls being generated for TLS variables:
1) A single __tls_init function per module
This initializes *all* TLS variables in the module, guarded by a
single __tls_guard variable to ensure it is only done once.
2) One _ZTHxx init function per TLS variable
Each of these is aliased to the module's __tls_init
3) One _ZTWxx wrapper function per TLS variable
This is called in place of accesses to that TLS variable. It invokes
the _ZTHxx init function for the variable to initialize it if
necessary.
I am concerned about generating the aux module __tls_init functions
and then promoting them as they contain initializations for all TLS
variables from the aux module - generating it each time the module is
included as an aux module seems inefficient at best.
What happens in the case where the TLS variable is declared extern and
accessed by a separate module (and essentially is what happens with my
patch when it is file static, promoted and accessed via an aux module)
is this: The _ZTHxx init functions are aliased to __tls_init in the
module containing the definition, and are externally-visible (after
promoting in the file-static exported primary module case). The
external module containing the reference (or the primary module that
imported the defining module as an aux module in the LIPO case)
generates a _ZTWxx wrapper for the TLS variable, which references its
_ZTHxx init function. This ends up resolved to the exported/promoted
_ZTHxx symbol in the defining module, which in turn is aliased to the
defining module's __tls_init function.
Teresa
>
> David
>
>
>
>
>>
>> Teresa
>>
>>>
>>> David
>>>
>>> On Thu, Mar 19, 2015 at 5:51 PM, Teresa Johnson <tejohnson@google.com> wrote:
>>>> On Thu, Mar 19, 2015 at 4:45 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>>> does generate_tls_wrapper also need to be suppressed for aux module?
>>>>
>>>> No, we generate the wrapper in the aux module and use it to access the
>>>> TLS variable and invoke it's init function (which is defined in the
>>>> variable's own module). Presumably we could generate that only in the
>>>> original module and promote it if necessary, but generating it in the
>>>> aux module does allow it to be inlined. This is essentially how the
>>>> TLS accesses are handled for extern TLS variables defined elsewhere
>>>> (wrapper generated in referring module).
>>>>
>>>> Teresa
>>>>
>>>>>
>>>>> David
>>>>>
>>>>> On Thu, Mar 19, 2015 at 4:11 PM, Teresa Johnson <tejohnson@google.com> wrote:
>>>>>> New patch below. Passes regression tests plus internal application build.
>>>>>>
>>>>>> 2015-03-19 Teresa Johnson <tejohnson@google.com>
>>>>>>
>>>>>> gcc/
>>>>>> Google ref b/19618364.
>>>>>> * cp/decl2.c (get_local_tls_init_fn): Assert on aux module.
>>>>>> (get_tls_init_fn): Promote non-public init functions if necessary
>>>>>> in LIPO mode, record new global at module scope.
>>>>>> (get_tls_wrapper_fn): Record new global at module scope.
>>>>>> (handle_tls_init): Skip in aux module, setup alias in exported
>>>>>> primary module.
>>>>>>
>>>>>> testsuite/
>>>>>> Google ref b/19618364.
>>>>>> * testsuite/g++.dg/tree-prof/lipo/tls.h: New test.
>>>>>> * testsuite/g++.dg/tree-prof/lipo/tls2.h: Ditto.
>>>>>> * testsuite/g++.dg/tree-prof/lipo/tls2_0.C: Ditto.
>>>>>> * testsuite/g++.dg/tree-prof/lipo/tls2_1.C: Ditto.
>>>>>> * testsuite/g++.dg/tree-prof/lipo/tls_0.C: Ditto.
>>>>>> * testsuite/g++.dg/tree-prof/lipo/tls_1.C: Ditto.
>>>>>>
>>>>>> Index: cp/decl2.c
>>>>>> ===================================================================
>>>>>> --- cp/decl2.c (revision 221425)
>>>>>> +++ cp/decl2.c (working copy)
>>>>>> @@ -55,6 +55,7 @@ along with GCC; see the file COPYING3. If not see
>>>>>> #include "langhooks.h"
>>>>>> #include "c-family/c-ada-spec.h"
>>>>>> #include "asan.h"
>>>>>> +#include "gcov-io.h"
>>>>>>
>>>>>> extern cpp_reader *parse_in;
>>>>>>
>>>>>> @@ -3024,6 +3025,9 @@ var_needs_tls_wrapper (tree var)
>>>>>> static tree
>>>>>> get_local_tls_init_fn (void)
>>>>>> {
>>>>>> + /* In LIPO mode we should not generate local init functions for
>>>>>> + the aux modules (see handle_tls_init). */
>>>>>> + gcc_assert (!L_IPO_IS_AUXILIARY_MODULE);
>>>>>> tree sname = get_identifier ("__tls_init");
>>>>>> tree fn = IDENTIFIER_GLOBAL_VALUE (sname);
>>>>>> if (!fn)
>>>>>> @@ -3057,14 +3061,39 @@ get_tls_init_fn (tree var)
>>>>>> if (!flag_extern_tls_init && DECL_EXTERNAL (var))
>>>>>> return NULL_TREE;
>>>>>>
>>>>>> + /* In LIPO mode we should not generate local init functions for
>>>>>> + aux modules. The wrapper will reference the variable's init function
>>>>>> + that is defined in its own primary module. Otherwise there is
>>>>>> + a name conflict between the primary and aux __tls_init functions,
>>>>>> + and difficulty ensuring each TLS variable is initialized exactly once.
>>>>>> + Therefore, if this is an aux module or an exported primary module, we
>>>>>> + need to ensure that the init function is available externally by
>>>>>> + promoting it if it is not already public. This is similar to the
>>>>>> + handling in promote_static_var_func, but we do it as the init function
>>>>>> + is created to avoid the need to detect and properly promote this
>>>>>> + artificial decl later on. */
>>>>>> + bool promote = L_IPO_IS_AUXILIARY_MODULE ||
>>>>>> + (L_IPO_COMP_MODE && PRIMARY_MODULE_EXPORTED);
>>>>>> +
>>>>>> #ifdef ASM_OUTPUT_DEF
>>>>>> /* If the variable is internal, or if we can't generate aliases,
>>>>>> - call the local init function directly. */
>>>>>> - if (!TREE_PUBLIC (var))
>>>>>> + call the local init function directly. Don't do this if we
>>>>>> + are in LIPO mode an may need to export the init function. Note
>>>>>> + that get_local_tls_init_fn will assert if it is called on an aux
>>>>>> + module. */
>>>>>> + if (!TREE_PUBLIC (var) && !promote)
>>>>>> #endif
>>>>>> return get_local_tls_init_fn ();
>>>>>>
>>>>>> tree sname = mangle_tls_init_fn (var);
>>>>>> + if (promote)
>>>>>> + {
>>>>>> + const char *name = IDENTIFIER_POINTER (sname);
>>>>>> + char *assembler_name = (char*) alloca (strlen (name) + 30);
>>>>>> + sprintf (assembler_name, "%s.cmo.%u", name, current_module_id);
>>>>>> + sname = get_identifier (assembler_name);
>>>>>> + }
>>>>>> +
>>>>>> tree fn = IDENTIFIER_GLOBAL_VALUE (sname);
>>>>>> if (!fn)
>>>>>> {
>>>>>> @@ -3072,7 +3101,18 @@ get_tls_init_fn (tree var)
>>>>>> build_function_type (void_type_node,
>>>>>> void_list_node));
>>>>>> SET_DECL_LANGUAGE (fn, lang_c);
>>>>>> - TREE_PUBLIC (fn) = TREE_PUBLIC (var);
>>>>>> + if (promote)
>>>>>> + {
>>>>>> + TREE_PUBLIC (fn) = 1;
>>>>>> + DECL_VISIBILITY (fn) = VISIBILITY_HIDDEN;
>>>>>> + DECL_VISIBILITY_SPECIFIED (fn) = 1;
>>>>>> + }
>>>>>> + else
>>>>>> + {
>>>>>> + TREE_PUBLIC (fn) = TREE_PUBLIC (var);
>>>>>> + DECL_VISIBILITY (fn) = DECL_VISIBILITY (var);
>>>>>> + DECL_VISIBILITY_SPECIFIED (fn) = DECL_VISIBILITY_SPECIFIED (var);
>>>>>> + }
>>>>>> DECL_ARTIFICIAL (fn) = true;
>>>>>> DECL_COMDAT (fn) = DECL_COMDAT (var);
>>>>>> DECL_EXTERNAL (fn) = DECL_EXTERNAL (var);
>>>>>> @@ -3091,8 +3131,6 @@ get_tls_init_fn (tree var)
>>>>>> else
>>>>>> DECL_WEAK (fn) = DECL_WEAK (var);
>>>>>> }
>>>>>> - DECL_VISIBILITY (fn) = DECL_VISIBILITY (var);
>>>>>> - DECL_VISIBILITY_SPECIFIED (fn) = DECL_VISIBILITY_SPECIFIED (var);
>>>>>> DECL_DLLIMPORT_P (fn) = DECL_DLLIMPORT_P (var);
>>>>>> DECL_IGNORED_P (fn) = 1;
>>>>>> mark_used (fn);
>>>>>> @@ -3100,6 +3138,11 @@ get_tls_init_fn (tree var)
>>>>>> DECL_BEFRIENDING_CLASSES (fn) = var;
>>>>>>
>>>>>> SET_IDENTIFIER_GLOBAL_VALUE (sname, fn);
>>>>>> + /* In LIPO mode make sure we record the new global value so that it
>>>>>> + is cleared before parsing the next aux module. */
>>>>>> + if (L_IPO_COMP_MODE && !is_parsing_done_p ())
>>>>>> + add_decl_to_current_module_scope (fn,
>>>>>> + NAMESPACE_LEVEL (global_namespace));
>>>>>> }
>>>>>> return fn;
>>>>>> }
>>>>>> @@ -3157,6 +3200,11 @@ get_tls_wrapper_fn (tree var)
>>>>>> DECL_BEFRIENDING_CLASSES (fn) = var;
>>>>>>
>>>>>> SET_IDENTIFIER_GLOBAL_VALUE (sname, fn);
>>>>>> + /* In LIPO mode make sure we record the new global value so that it
>>>>>> + is cleared before parsing the next aux module. */
>>>>>> + if (L_IPO_COMP_MODE && !is_parsing_done_p ())
>>>>>> + add_decl_to_current_module_scope (fn,
>>>>>> + NAMESPACE_LEVEL (global_namespace));
>>>>>> }
>>>>>> return fn;
>>>>>> }
>>>>>> @@ -4179,6 +4227,14 @@ clear_decl_external (struct cgraph_node *node, voi
>>>>>> static void
>>>>>> handle_tls_init (void)
>>>>>> {
>>>>>> + /* In LIPO mode we should not generate local init functions for
>>>>>> + aux modules. The wrapper will reference the variable's init function
>>>>>> + that is defined in its own primary module. Otherwise there is
>>>>>> + a name conflict between the primary and aux __tls_init functions,
>>>>>> + and difficulty ensuring each TLS variable is initialized exactly once. */
>>>>>> + if (L_IPO_IS_AUXILIARY_MODULE)
>>>>>> + return;
>>>>>> +
>>>>>> tree vars = prune_vars_needing_no_initialization (&tls_aggregates);
>>>>>> if (vars == NULL_TREE)
>>>>>> return;
>>>>>> @@ -4213,8 +4269,12 @@ handle_tls_init (void)
>>>>>> one_static_initialization_or_destruction (var, init, true);
>>>>>>
>>>>>> #ifdef ASM_OUTPUT_DEF
>>>>>> - /* Output init aliases even with -fno-extern-tls-init. */
>>>>>> - if (TREE_PUBLIC (var))
>>>>>> + /* Output init aliases even with -fno-extern-tls-init. Also
>>>>>> + export in LIPO mode if the primary module may be exported,
>>>>>> + in which case the init function may be referenced externally
>>>>>> + (see comments in get_tls_init_fn). */
>>>>>> + if (TREE_PUBLIC (var) ||
>>>>>> + (L_IPO_COMP_MODE && PRIMARY_MODULE_EXPORTED))
>>>>>> {
>>>>>> tree single_init_fn = get_tls_init_fn (var);
>>>>>> if (single_init_fn == NULL_TREE)
>>>>>> Index: testsuite/g++.dg/tree-prof/lipo/tls.h
>>>>>> ===================================================================
>>>>>> --- testsuite/g++.dg/tree-prof/lipo/tls.h (revision 0)
>>>>>> +++ testsuite/g++.dg/tree-prof/lipo/tls.h (working copy)
>>>>>> @@ -0,0 +1,16 @@
>>>>>> +extern int NextId();
>>>>>> +
>>>>>> +class TLSClass {
>>>>>> + public:
>>>>>> + TLSClass() {
>>>>>> + id = NextId();
>>>>>> + bar = 1;
>>>>>> + }
>>>>>> + ~TLSClass() {}
>>>>>> + int id;
>>>>>> + int bar;
>>>>>> +};
>>>>>> +extern TLSClass* NextTLSClass();
>>>>>> +extern void *SetTLSClass(TLSClass *a);
>>>>>> +extern TLSClass *GetTLSClass();
>>>>>> +extern thread_local TLSClass* current_tls_;
>>>>>> Index: testsuite/g++.dg/tree-prof/lipo/tls2.h
>>>>>> ===================================================================
>>>>>> --- testsuite/g++.dg/tree-prof/lipo/tls2.h (revision 0)
>>>>>> +++ testsuite/g++.dg/tree-prof/lipo/tls2.h (working copy)
>>>>>> @@ -0,0 +1,15 @@
>>>>>> +extern int NextId();
>>>>>> +
>>>>>> +class TLSClass {
>>>>>> + public:
>>>>>> + TLSClass() {
>>>>>> + id = NextId();
>>>>>> + bar = 1;
>>>>>> + }
>>>>>> + ~TLSClass() {}
>>>>>> + int id;
>>>>>> + int bar;
>>>>>> +};
>>>>>> +extern TLSClass* NextTLSClass();
>>>>>> +extern void *SetTLSClass(TLSClass *a);
>>>>>> +extern TLSClass *GetTLSClass();
>>>>>> Index: testsuite/g++.dg/tree-prof/lipo/tls2_0.C
>>>>>> ===================================================================
>>>>>> --- testsuite/g++.dg/tree-prof/lipo/tls2_0.C (revision 0)
>>>>>> +++ testsuite/g++.dg/tree-prof/lipo/tls2_0.C (working copy)
>>>>>> @@ -0,0 +1,10 @@
>>>>>> +// { dg-options "-std=c++11 -O2 --param=lipo-sampling-period=1" }
>>>>>> +#include "tls2.h"
>>>>>> +
>>>>>> +static thread_local TLSClass* current_tls_ = NextTLSClass();
>>>>>> +void *SetTLSClass(TLSClass *a) {
>>>>>> + current_tls_ = a;
>>>>>> +}
>>>>>> +TLSClass *GetTLSClass() {
>>>>>> + return current_tls_;
>>>>>> +}
>>>>>> Index: testsuite/g++.dg/tree-prof/lipo/tls2_1.C
>>>>>> ===================================================================
>>>>>> --- testsuite/g++.dg/tree-prof/lipo/tls2_1.C (revision 0)
>>>>>> +++ testsuite/g++.dg/tree-prof/lipo/tls2_1.C (working copy)
>>>>>> @@ -0,0 +1,26 @@
>>>>>> +// { dg-options "-std=c++11 -O2 --param=lipo-sampling-period=1" }
>>>>>> +#include <stdio.h>
>>>>>> +#include <stdlib.h>
>>>>>> +#include <new>
>>>>>> +#include "tls2.h"
>>>>>> +TLSClass* NextTLSClass() {
>>>>>> + return new TLSClass();
>>>>>> +}
>>>>>> +int NextId() {
>>>>>> + static int id = 0;
>>>>>> + return id++;
>>>>>> +}
>>>>>> +static thread_local TLSClass* current_tls2_ = NextTLSClass();
>>>>>> +void *SetTLSClass2(TLSClass *a) {
>>>>>> + current_tls2_ = a;
>>>>>> +}
>>>>>> +int main() {
>>>>>> + printf ("Id %d\n", GetTLSClass()->id);
>>>>>> + TLSClass *A = NextTLSClass();
>>>>>> + SetTLSClass(A);
>>>>>> + printf ("Id %d\n", GetTLSClass()->id);
>>>>>> + printf ("Id %d\n", current_tls2_->id);
>>>>>> + A = NextTLSClass();
>>>>>> + SetTLSClass2(A);
>>>>>> + printf ("Id %d\n", current_tls2_->id);
>>>>>> +}
>>>>>> Index: testsuite/g++.dg/tree-prof/lipo/tls_0.C
>>>>>> ===================================================================
>>>>>> --- testsuite/g++.dg/tree-prof/lipo/tls_0.C (revision 0)
>>>>>> +++ testsuite/g++.dg/tree-prof/lipo/tls_0.C (working copy)
>>>>>> @@ -0,0 +1,10 @@
>>>>>> +// { dg-options "-std=c++11 -O2 --param=lipo-sampling-period=1" }
>>>>>> +#include "tls.h"
>>>>>> +
>>>>>> +thread_local TLSClass* current_tls_ = NextTLSClass();
>>>>>> +void *SetTLSClass(TLSClass *a) {
>>>>>> + current_tls_ = a;
>>>>>> +}
>>>>>> +TLSClass *GetTLSClass() {
>>>>>> + return current_tls_;
>>>>>> +}
>>>>>> Index: testsuite/g++.dg/tree-prof/lipo/tls_1.C
>>>>>> ===================================================================
>>>>>> --- testsuite/g++.dg/tree-prof/lipo/tls_1.C (revision 0)
>>>>>> +++ testsuite/g++.dg/tree-prof/lipo/tls_1.C (working copy)
>>>>>> @@ -0,0 +1,32 @@
>>>>>> +// { dg-options "-std=c++11 -O2 --param=lipo-sampling-period=1" }
>>>>>> +#include <stdio.h>
>>>>>> +#include <stdlib.h>
>>>>>> +#include <new>
>>>>>> +#include "tls.h"
>>>>>> +TLSClass* NextTLSClass() {
>>>>>> + return new TLSClass();
>>>>>> +}
>>>>>> +int NextId() {
>>>>>> + static int id = 0;
>>>>>> + return id++;
>>>>>> +}
>>>>>> +void *SetTLSClassHere(TLSClass *a) {
>>>>>> + current_tls_ = a;
>>>>>> +}
>>>>>> +thread_local TLSClass* current_tls2_ = NextTLSClass();
>>>>>> +void *SetTLSClass2(TLSClass *a) {
>>>>>> + current_tls2_ = a;
>>>>>> +}
>>>>>> +int main() {
>>>>>> + printf ("Id %d\n", GetTLSClass()->id);
>>>>>> + TLSClass *A = NextTLSClass();
>>>>>> + SetTLSClass(A);
>>>>>> + printf ("Id %d\n", GetTLSClass()->id);
>>>>>> + A = NextTLSClass();
>>>>>> + SetTLSClassHere(A);
>>>>>> + printf ("Id %d\n", GetTLSClass()->id);
>>>>>> + printf ("Id %d\n", current_tls2_->id);
>>>>>> + A = NextTLSClass();
>>>>>> + SetTLSClass2(A);
>>>>>> + printf ("Id %d\n", current_tls2_->id);
>>>>>> +}
>>>>>>
>>>>>> On Thu, Mar 19, 2015 at 6:09 AM, Teresa Johnson <tejohnson@google.com> wrote:
>>>>>>> On Wed, Mar 18, 2015 at 9:25 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>>>>>> get_local_tls_init_fn can be called from other contexts other than
>>>>>>>> 'handle_tls_init' -- is the added new assertion safe ?
>>>>>>>
>>>>>>> In fact there is still an issue here, for file static TLS vars. Will
>>>>>>> work on a fix and send the original test case (forgot to include in
>>>>>>> first patch) and the new one with the fixed patch.
>>>>>>>
>>>>>>> Teresa
>>>>>>>
>>>>>>>>
>>>>>>>> David
>>>>>>>>
>>>>>>>> On Wed, Mar 18, 2015 at 9:18 PM, Teresa Johnson <tejohnson@google.com>
>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>> Ensure TLS variable wrapper and init functions are recorded at
>>>>>>>>> the module scope upon creation so that they are cleared when
>>>>>>>>> popping the module scope in between modules in LIPO mode.
>>>>>>>>>
>>>>>>>>> Also, do not generate a local TLS init function (__tls_init)
>>>>>>>>> for aux functions, only in the primary modules.
>>>>>>>>>
>>>>>>>>> Passes regression tests. Ok for Google branches?
>>>>>>>>> Teresa
>>>>>>>>>
>>>>>>>>> 2015-03-18 Teresa Johnson <tejohnson@google.com>
>>>>>>>>>
>>>>>>>>> Google ref b/19618364.
>>>>>>>>> * cp/decl2.c (get_local_tls_init_fn): Assert on aux module.
>>>>>>>>> (get_tls_init_fn): Record new global decl.
>>>>>>>>> (get_tls_wrapper_fn): Ditto.
>>>>>>>>> (handle_tls_init): Skip aux modules.
>>>>>>>>>
>>>>>>>>> Index: cp/decl2.c
>>>>>>>>> ===================================================================
>>>>>>>>> --- cp/decl2.c (revision 221425)
>>>>>>>>> +++ cp/decl2.c (working copy)
>>>>>>>>> @@ -3036,6 +3036,9 @@ get_local_tls_init_fn (void)
>>>>>>>>> DECL_ARTIFICIAL (fn) = true;
>>>>>>>>> mark_used (fn);
>>>>>>>>> SET_IDENTIFIER_GLOBAL_VALUE (sname, fn);
>>>>>>>>> + /* In LIPO mode we should not generate local init functions for
>>>>>>>>> + the aux modules (see handle_tls_init). */
>>>>>>>>> + gcc_assert (!L_IPO_IS_AUXILIARY_MODULE);
>>>>>>>>> }
>>>>>>>>> return fn;
>>>>>>>>> }
>>>>>>>>> @@ -3100,6 +3103,11 @@ get_tls_init_fn (tree var)
>>>>>>>>> DECL_BEFRIENDING_CLASSES (fn) = var;
>>>>>>>>>
>>>>>>>>> SET_IDENTIFIER_GLOBAL_VALUE (sname, fn);
>>>>>>>>> + /* In LIPO mode make sure we record the new global value so that it
>>>>>>>>> + is cleared before parsing the next aux module. */
>>>>>>>>> + if (L_IPO_COMP_MODE && !is_parsing_done_p ())
>>>>>>>>> + add_decl_to_current_module_scope (fn,
>>>>>>>>> + NAMESPACE_LEVEL
>>>>>>>>> (global_namespace));
>>>>>>>>> }
>>>>>>>>> return fn;
>>>>>>>>> }
>>>>>>>>> @@ -3157,6 +3165,11 @@ get_tls_wrapper_fn (tree var)
>>>>>>>>> DECL_BEFRIENDING_CLASSES (fn) = var;
>>>>>>>>>
>>>>>>>>> SET_IDENTIFIER_GLOBAL_VALUE (sname, fn);
>>>>>>>>> + /* In LIPO mode make sure we record the new global value so that it
>>>>>>>>> + is cleared before parsing the next aux module. */
>>>>>>>>> + if (L_IPO_COMP_MODE && !is_parsing_done_p ())
>>>>>>>>> + add_decl_to_current_module_scope (fn,
>>>>>>>>> + NAMESPACE_LEVEL
>>>>>>>>> (global_namespace));
>>>>>>>>> }
>>>>>>>>> return fn;
>>>>>>>>> }
>>>>>>>>> @@ -4179,6 +4192,14 @@ clear_decl_external (struct cgraph_node *node, voi
>>>>>>>>> static void
>>>>>>>>> handle_tls_init (void)
>>>>>>>>> {
>>>>>>>>> + /* In LIPO mode we should not generate local init functions for
>>>>>>>>> + aux modules. The wrapper will reference the variable's init function
>>>>>>>>> + that is defined in its own primary module. Otherwise there is
>>>>>>>>> + a name conflict between the primary and aux __tls_init functions,
>>>>>>>>> + and difficulty ensuring each TLS variable is initialized exactly
>>>>>>>>> once. */
>>>>>>>>> + if (L_IPO_IS_AUXILIARY_MODULE)
>>>>>>>>> + return;
>>>>>>>>> +
>>>>>>>>> tree vars = prune_vars_needing_no_initialization (&tls_aggregates);
>>>>>>>>> if (vars == NULL_TREE)
>>>>>>>>> return;
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
>>>>
>>>>
>>>>
>>>> --
>>>> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
>>
>>
>>
>> --
>> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
--
Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413