[llvm] r274699 - ThinLTO: Add test cases for promote+internalize.

Tue Jul 25 16:24:08 PDT 2017

On Tue, Jul 25, 2017 at 2:29 PM, David Blaikie <dblaikie at gmail.com> wrote:

> Hey Peter,
>
> Bit of thread necromancy here - but I'm trying to change some things wrt
> alias+linkonce_odr (going to make it behave like the alias+external case,
> for simplicity, less duplication, and simplified debug info) & this test is
> failing:
>
> My change causes none of the aliasees to be imported (not even those
> linkonce_odr ones).
>

Is that a good idea? I would have thought that we'd want to go in the
opposite direction and try to import more functions that use aliases. I
believe that is blocked on support for available_externally aliases though
(this thread has the most recent discussion I can find on that topic:
http://lists.llvm.org/pipermail/llvm-dev/2017-January/109227.html).

This causes -thinlto-action=internalize to fail ("-internalize will not
> perform without -exportedsymbol").
>

Is it really failing because of that?
http://llvm-cs.pcc.me.uk/tools/llvm-lto/llvm-lto.cpp#618
Looks like it just prints a warning.

It looks like if I fix this by passing -exported-symbol=main, nothing is
> internalized (all the aliases are called from main) so it may defeat the
> purpose of this test?
>

Right, if we export main then that would prevent us from internalizing
anything across modules that is referenced by main, as we don't currently
support cross-module internalization.

(I don't really understand how this was working/what it was doing before,
> though: What kept the aliasees alive if not the calls from main? Maybe a
> record in the index saying "these are being used elsewhere" - but why isn't
> there a similar record for the aliases that would've stopped them from
> being internalized in the first place?)
>

I don't recall for sure but I believe that the point of that part of the
test was to show that if no symbols are exported, the linkage changes
applied by promote are unimportant because they are wiped out by a later
internalize pass (which would internalize pretty much everything because
nothing is exported).

So I think the right change to make in that part of the test (if we wanted
to go with your proposed change) would be to test that the remaining
declarations are internal.

Peter

> Preciate any thoughts you have here,
>
> - Dave
>
>
> On Wed, Jul 6, 2016 at 4:00 PM Peter Collingbourne via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: pcc
>> Date: Wed Jul  6 17:53:02 2016
>> New Revision: 274699
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=274699&view=rev
>> Log:
>> ThinLTO: Add test cases for promote+internalize.
>>
>> This tests the effect of both promotion and internalization on a module,
>> and helps show that D21883 is NFC wrt promotion+internalization.
>>
>> Differential Revision: http://reviews.llvm.org/D21915
>>
>> Modified:
>>     llvm/trunk/test/ThinLTO/X86/alias_import.ll
>>     llvm/trunk/test/ThinLTO/X86/weak_resolution.ll
>>
>> Modified: llvm/trunk/test/ThinLTO/X86/alias_import.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ThinLTO/
>> X86/alias_import.ll?rev=274699&r1=274698&r2=274699&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/test/ThinLTO/X86/alias_import.ll (original)
>> +++ llvm/trunk/test/ThinLTO/X86/alias_import.ll Wed Jul  6 17:53:02 2016
>> @@ -2,6 +2,7 @@
>>  ; RUN: opt -module-summary %p/Inputs/alias_import.ll -o %t2.bc
>>  ; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t1.bc %t2.bc
>>  ; RUN: llvm-lto -thinlto-action=promote -thinlto-index %t.index.bc
>> %t2.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=PROMOTE
>> +; RUN: llvm-lto -thinlto-action=promote -thinlto-index %t.index.bc
>> %t2.bc -o - | llvm-lto -thinlto-action=internalize -thinlto-index
>> %t.index.bc -thinlto-module-id=%t2.bc - -o - | llvm-dis -o - | FileCheck %s
>> --check-prefix=PROMOTE-INTERNALIZE
>>  ; RUN: llvm-lto -thinlto-action=import -thinlto-index %t.index.bc %t1.bc
>> -o - | llvm-dis -o - | FileCheck %s --check-prefix=IMPORT
>>
>>  ;
>> @@ -86,7 +87,45 @@
>>  ; IMPORT-DAG: declare void @weakfuncWeakODRAlias()
>>  ; IMPORT-DAG: declare void @weakfuncLinkonceODRAlias()
>>
>> -
>> +; Promotion + internalization should internalize all of these, except
>> for aliases of
>> +; linkonce_odr functions, because alias to linkonce_odr are the only
>> aliases we will
>> +; import (see selectCallee() in FunctionImport.cpp).
>> +; PROMOTE-INTERNALIZE-DAG: @globalfuncAlias = internal alias void (...),
>> bitcast (void ()* @globalfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @globalfuncWeakAlias = internal alias void
>> (...), bitcast (void ()* @globalfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @globalfuncLinkonceAlias = internal alias
>> void (...), bitcast (void ()* @globalfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @globalfuncWeakODRAlias = internal alias void
>> (...), bitcast (void ()* @globalfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @globalfuncLinkonceODRAlias = internal alias
>> void (...), bitcast (void ()* @globalfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @internalfuncAlias = internal alias void
>> (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @internalfuncWeakAlias = internal alias void
>> (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @internalfuncLinkonceAlias = internal alias
>> void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @internalfuncWeakODRAlias = internal alias
>> void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @internalfuncLinkonceODRAlias = internal
>> alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkonceODRfuncAlias = alias void (...),
>> bitcast (void ()* @linkonceODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkonceODRfuncWeakAlias = internal alias
>> void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkonceODRfuncLinkonceAlias = internal
>> alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkonceODRfuncWeakODRAlias = weak_odr alias
>> void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkonceODRfuncLinkonceODRAlias = weak_odr
>> alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakODRfuncAlias = internal alias void
>> (...), bitcast (void ()* @weakODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakODRfuncWeakAlias = internal alias void
>> (...), bitcast (void ()* @weakODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakODRfuncLinkonceAlias = internal alias
>> void (...), bitcast (void ()* @weakODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakODRfuncWeakODRAlias = internal alias
>> void (...), bitcast (void ()* @weakODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakODRfuncLinkonceODRAlias = internal alias
>> void (...), bitcast (void ()* @weakODRfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkoncefuncAlias = internal alias void
>> (...), bitcast (void ()* @linkoncefunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkoncefuncWeakAlias = internal alias void
>> (...), bitcast (void ()* @linkoncefunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkoncefuncLinkonceAlias = internal alias
>> void (...), bitcast (void ()* @linkoncefunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkoncefuncWeakODRAlias = internal alias
>> void (...), bitcast (void ()* @linkoncefunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @linkoncefuncLinkonceODRAlias = internal
>> alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakfuncAlias = internal alias void (...),
>> bitcast (void ()* @weakfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakfuncWeakAlias = internal alias void
>> (...), bitcast (void ()* @weakfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakfuncLinkonceAlias = internal alias void
>> (...), bitcast (void ()* @weakfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakfuncWeakODRAlias = internal alias void
>> (...), bitcast (void ()* @weakfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: @weakfuncLinkonceODRAlias = internal alias
>> void (...), bitcast (void ()* @weakfunc to void (...)*)
>> +; PROMOTE-INTERNALIZE-DAG: define internal void @globalfunc()
>> +; PROMOTE-INTERNALIZE-DAG: define internal void @internalfunc.llvm.0()
>> +; PROMOTE-INTERNALIZE-DAG: define internal void @linkonceODRfunc()
>> +; PROMOTE-INTERNALIZE-DAG: define internal void @weakODRfunc()
>> +; PROMOTE-INTERNALIZE-DAG: define internal void @linkoncefunc()
>> +; PROMOTE-INTERNALIZE-DAG: define internal void @weakfunc()
>>
>>  define i32 @main() #0 {
>>  entry:
>>
>> Modified: llvm/trunk/test/ThinLTO/X86/weak_resolution.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ThinLTO/
>> X86/weak_resolution.ll?rev=274699&r1=274698&r2=274699&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/test/ThinLTO/X86/weak_resolution.ll (original)
>> +++ llvm/trunk/test/ThinLTO/X86/weak_resolution.ll Wed Jul  6 17:53:02
>> 2016
>> @@ -7,6 +7,7 @@
>>  ; non-prevailing ODR are not kept when possible, but non-ODR
>> non-prevailing
>>  ; are not affected.
>>  ; RUN: llvm-lto -thinlto-action=promote %t.bc -thinlto-index=%t3.bc -o -
>> | llvm-dis -o - | FileCheck %s --check-prefix=MOD1
>> +; RUN: llvm-lto -thinlto-action=promote %t.bc -thinlto-index=%t3.bc
>> -exported-symbol=linkoncefunc -o - | llvm-lto -thinlto-action=internalize
>> -thinlto-module-id=%t.bc - -thinlto-index=%t3.bc
>> -exported-symbol=linkoncefunc -o - | llvm-dis -o - | FileCheck %s
>> --check-prefix=MOD1-INT
>>  ; RUN: llvm-lto -thinlto-action=promote %t2.bc -thinlto-index=%t3.bc -o
>> - | llvm-dis -o - | FileCheck %s --check-prefix=MOD2
>>  ; When exported, we always preserve a linkonce
>>  ; RUN: llvm-lto -thinlto-action=promote %t.bc -thinlto-index=%t3.bc -o -
>> --exported-symbol=linkonceodrfuncInSingleModule | llvm-dis -o - |
>> FileCheck %s --check-prefix=EXPORTED
>> @@ -47,6 +48,7 @@ entry:
>>    ret void
>>  }
>>  ; MOD1: define weak void @linkoncefunc()
>> +; MOD1-INT: define weak void @linkoncefunc()
>>  ; MOD2: define linkonce void @linkoncefunc()
>>  define linkonce void @linkoncefunc() #0 {
>>  entry:
>> @@ -66,6 +68,7 @@ entry:
>>  }
>>
>>  ; MOD1: define linkonce_odr void @linkonceodrfuncInSingleModule()
>> +; MOD1-INT: define internal void @linkonceodrfuncInSingleModule()
>>  ; EXPORTED: define weak_odr void @linkonceodrfuncInSingleModule()
>>  define linkonce_odr void @linkonceodrfuncInSingleModule() #0 {
>>  entry:
>>
>>
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>>
>

-- 
-- 
Peter
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