[lld] r319154 - Revert r319008, "[ELF] Do not keep symbols if they referenced only from discarded sections."
Rafael Avila de Espindola via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 28 12:04:57 PST 2017
I think I found the problem.
Thanks,
Rafael
Rafael Avila de Espindola <rafael.espindola at gmail.com> writes:
> Do you have a testcase?
>
> I have started a lto bootstrap to see if I can reproduce it. Do you have
> a link to a bot failure?
>
> Igor Kudrin via llvm-commits <llvm-commits at lists.llvm.org> writes:
>
>> Author: ikudrin
>> Date: Tue Nov 28 00:39:40 2017
>> New Revision: 319154
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=319154&view=rev
>> Log:
>> Revert r319008, "[ELF] Do not keep symbols if they referenced only from discarded sections."
>> and r319051, "Add a missing test."
>>
>> r319008 broke the LTO bots;
>> r319051 depends on changes in r319008.
>>
>> Removed:
>> lld/trunk/test/ELF/Inputs/gc-sections-shared2.s
>> lld/trunk/test/ELF/gc-collect-undefined.s
>> Modified:
>> lld/trunk/ELF/MarkLive.cpp
>> lld/trunk/ELF/SymbolTable.cpp
>> lld/trunk/ELF/Symbols.h
>> lld/trunk/ELF/Writer.cpp
>> lld/trunk/test/ELF/gc-sections-shared.s
>>
>> Modified: lld/trunk/ELF/MarkLive.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/MarkLive.cpp?rev=319154&r1=319153&r2=319154&view=diff
>> ==============================================================================
>> --- lld/trunk/ELF/MarkLive.cpp (original)
>> +++ lld/trunk/ELF/MarkLive.cpp Tue Nov 28 00:39:40 2017
>> @@ -64,12 +64,6 @@ static void resolveReloc(InputSectionBas
>> std::function<void(InputSectionBase *, uint64_t)> Fn) {
>> Symbol &B = Sec.getFile<ELFT>()->getRelocTargetSym(Rel);
>>
>> - // If a symbol is referenced in a live section, it is used.
>> - B.Used = true;
>> - if (auto *SS = dyn_cast<SharedSymbol>(&B))
>> - if (!SS->isWeak())
>> - SS->getFile<ELFT>()->IsNeeded = true;
>> -
>> if (auto *D = dyn_cast<Defined>(&B)) {
>> if (!D->Section)
>> return;
>>
>> Modified: lld/trunk/ELF/SymbolTable.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.cpp?rev=319154&r1=319153&r2=319154&view=diff
>> ==============================================================================
>> --- lld/trunk/ELF/SymbolTable.cpp (original)
>> +++ lld/trunk/ELF/SymbolTable.cpp Tue Nov 28 00:39:40 2017
>> @@ -305,8 +305,7 @@ Symbol *SymbolTable::addUndefined(String
>> S->Binding = Binding;
>> if (Binding != STB_WEAK) {
>> if (auto *SS = dyn_cast<SharedSymbol>(S))
>> - if (!Config->GcSections)
>> - SS->getFile<ELFT>()->IsNeeded = true;
>> + SS->getFile<ELFT>()->IsNeeded = true;
>> }
>> if (auto *L = dyn_cast<Lazy>(S)) {
>> // An undefined weak will not fetch archive members. See comment on Lazy in
>> @@ -501,7 +500,7 @@ void SymbolTable::addShared(StringRef Na
>> Alignment, Verdef);
>> if (!WasInserted) {
>> S->Binding = Binding;
>> - if (!S->isWeak() && !Config->GcSections)
>> + if (!S->isWeak())
>> File->IsNeeded = true;
>> }
>> }
>>
>> Modified: lld/trunk/ELF/Symbols.h
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Symbols.h?rev=319154&r1=319153&r2=319154&view=diff
>> ==============================================================================
>> --- lld/trunk/ELF/Symbols.h (original)
>> +++ lld/trunk/ELF/Symbols.h Tue Nov 28 00:39:40 2017
>> @@ -134,8 +134,8 @@ protected:
>> uint8_t Type)
>> : Binding(Binding), SymbolKind(K), NeedsPltAddr(false),
>> IsInGlobalMipsGot(false), Is32BitMipsGot(false), IsInIplt(false),
>> - IsInIgot(false), IsPreemptible(false), Used(!Config->GcSections),
>> - Type(Type), StOther(StOther), Name(Name) {}
>> + IsInIgot(false), IsPreemptible(false), Type(Type), StOther(StOther),
>> + Name(Name) {}
>>
>> const unsigned SymbolKind : 8;
>>
>> @@ -157,9 +157,6 @@ public:
>>
>> unsigned IsPreemptible : 1;
>>
>> - // True if an undefined or shared symbol is used from a live section.
>> - unsigned Used : 1;
>> -
>> // The following fields have the same meaning as the ELF symbol attributes.
>> uint8_t Type; // symbol type
>> uint8_t StOther; // st_other field value
>>
>> Modified: lld/trunk/ELF/Writer.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=319154&r1=319153&r2=319154&view=diff
>> ==============================================================================
>> --- lld/trunk/ELF/Writer.cpp (original)
>> +++ lld/trunk/ELF/Writer.cpp Tue Nov 28 00:39:40 2017
>> @@ -448,9 +448,8 @@ static bool includeInSymtab(const Symbol
>> if (auto *S = dyn_cast<MergeInputSection>(Sec))
>> if (!S->getSectionPiece(D->Value)->Live)
>> return false;
>> - return true;
>> }
>> - return B.Used;
>> + return true;
>> }
>>
>> // Local symbols are not in the linker's symbol table. This function scans
>>
>> Removed: lld/trunk/test/ELF/Inputs/gc-sections-shared2.s
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/Inputs/gc-sections-shared2.s?rev=319153&view=auto
>> ==============================================================================
>> --- lld/trunk/test/ELF/Inputs/gc-sections-shared2.s (original)
>> +++ lld/trunk/test/ELF/Inputs/gc-sections-shared2.s (removed)
>> @@ -1,3 +0,0 @@
>> -.global qux
>> -.type qux, @function
>> -qux:
>>
>> Removed: lld/trunk/test/ELF/gc-collect-undefined.s
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/gc-collect-undefined.s?rev=319153&view=auto
>> ==============================================================================
>> --- lld/trunk/test/ELF/gc-collect-undefined.s (original)
>> +++ lld/trunk/test/ELF/gc-collect-undefined.s (removed)
>> @@ -1,19 +0,0 @@
>> -# REQUIRES: x86
>> -# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
>> -# RUN: ld.lld %t -o %tout --gc-sections -shared
>> -# RUN: llvm-nm -D %tout | FileCheck %s
>> -
>> -# CHECK-NOT: qux
>> -# CHECK: bar
>> -# CHECK-NOT: qux
>> -
>> - .global foo,bar,qux
>> - .local baz
>> -
>> - .section .data.foo,"aw",%progbits
>> -foo:
>> - .dc.a bar
>> -
>> - .section .bata.baz,"aw",%progbits
>> -baz:
>> - .dc.a qux
>>
>> Modified: lld/trunk/test/ELF/gc-sections-shared.s
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/gc-sections-shared.s?rev=319154&r1=319153&r2=319154&view=diff
>> ==============================================================================
>> --- lld/trunk/test/ELF/gc-sections-shared.s (original)
>> +++ lld/trunk/test/ELF/gc-sections-shared.s Tue Nov 28 00:39:40 2017
>> @@ -1,18 +1,14 @@
>> # REQUIRES: x86
>> # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/shared.s -o %t2.o
>> # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/gc-sections-shared.s -o %t3.o
>> -# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/gc-sections-shared2.s -o %t4.o
>> # RUN: ld.lld -shared %t2.o -o %t2.so
>> # RUN: ld.lld -shared %t3.o -o %t3.so
>> -# RUN: ld.lld -shared %t4.o -o %t4.so
>> # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
>> -# RUN: ld.lld --gc-sections --export-dynamic-symbol foo -o %t %t.o --as-needed %t2.so %t3.so %t4.so
>> +# RUN: ld.lld --gc-sections --export-dynamic-symbol foo -o %t %t.o --as-needed %t2.so %t3.so
>> # RUN: llvm-readobj --dynamic-table --dyn-symbols %t | FileCheck %s
>>
>> # This test the property that we have a needed line for every undefined.
>> -# It would also be OK to keep bar2 and the need for %t2.so
>> -# At the same time, weak symbols should not cause adding DT_NEEDED;
>> -# this case is checked with symbol qux and %t4.so.
>> +# It would also be OK to drop bar2 and the need for the .so
>>
>> # CHECK: DynamicSymbols [
>> # CHECK-NEXT: Symbol {
>> @@ -25,16 +21,16 @@
>> # CHECK-NEXT: Section: Undefined (0x0)
>> # CHECK-NEXT: }
>> # CHECK-NEXT: Symbol {
>> -# CHECK-NEXT: Name: bar
>> +# CHECK-NEXT: Name: bar2
>> # CHECK-NEXT: Value:
>> # CHECK-NEXT: Size:
>> # CHECK-NEXT: Binding: Global
>> # CHECK-NEXT: Type:
>> # CHECK-NEXT: Other:
>> -# CHECK-NEXT: Section: .text
>> +# CHECK-NEXT: Section: Undefined
>> # CHECK-NEXT: }
>> # CHECK-NEXT: Symbol {
>> -# CHECK-NEXT: Name: foo
>> +# CHECK-NEXT: Name: bar
>> # CHECK-NEXT: Value:
>> # CHECK-NEXT: Size:
>> # CHECK-NEXT: Binding: Global
>> @@ -43,13 +39,13 @@
>> # CHECK-NEXT: Section: .text
>> # CHECK-NEXT: }
>> # CHECK-NEXT: Symbol {
>> -# CHECK-NEXT: Name: qux
>> +# CHECK-NEXT: Name: foo
>> # CHECK-NEXT: Value:
>> # CHECK-NEXT: Size:
>> -# CHECK-NEXT: Binding: Weak
>> +# CHECK-NEXT: Binding: Global
>> # CHECK-NEXT: Type:
>> # CHECK-NEXT: Other:
>> -# CHECK-NEXT: Section: Undefined
>> +# CHECK-NEXT: Section: .text
>> # CHECK-NEXT: }
>> # CHECK-NEXT: Symbol {
>> # CHECK-NEXT: Name: baz
>> @@ -63,65 +59,10 @@
>> # CHECK-NEXT: ]
>>
>> # CHECK-NOT: NEEDED
>> +# CHECK: NEEDED Shared library: [{{.*}}2.so]
>> # CHECK: NEEDED Shared library: [{{.*}}3.so]
>> # CHECK-NOT: NEEDED
>>
>> -# Test with %t.o at the end too.
>> -# RUN: ld.lld --gc-sections --export-dynamic-symbol foo -o %t --as-needed %t2.so %t3.so %t4.so %t.o
>> -# RUN: llvm-readobj --dynamic-table --dyn-symbols %t | FileCheck --check-prefix=CHECK2 %s
>> -
>> -# CHECK2: DynamicSymbols [
>> -# CHECK2-NEXT: Symbol {
>> -# CHECK2-NEXT: Name:
>> -# CHECK2-NEXT: Value:
>> -# CHECK2-NEXT: Size:
>> -# CHECK2-NEXT: Binding: Local
>> -# CHECK2-NEXT: Type:
>> -# CHECK2-NEXT: Other:
>> -# CHECK2-NEXT: Section: Undefined (0x0)
>> -# CHECK2-NEXT: }
>> -# CHECK2-NEXT: Symbol {
>> -# CHECK2-NEXT: Name: bar
>> -# CHECK2-NEXT: Value:
>> -# CHECK2-NEXT: Size:
>> -# CHECK2-NEXT: Binding: Global
>> -# CHECK2-NEXT: Type:
>> -# CHECK2-NEXT: Other:
>> -# CHECK2-NEXT: Section: .text
>> -# CHECK2-NEXT: }
>> -# CHECK2-NEXT: Symbol {
>> -# CHECK2-NEXT: Name: qux
>> -# CHECK2-NEXT: Value:
>> -# CHECK2-NEXT: Size:
>> -# CHECK2-NEXT: Binding: Weak
>> -# CHECK2-NEXT: Type:
>> -# CHECK2-NEXT: Other:
>> -# CHECK2-NEXT: Section: Undefined
>> -# CHECK2-NEXT: }
>> -# CHECK2-NEXT: Symbol {
>> -# CHECK2-NEXT: Name: foo
>> -# CHECK2-NEXT: Value:
>> -# CHECK2-NEXT: Size:
>> -# CHECK2-NEXT: Binding: Global
>> -# CHECK2-NEXT: Type:
>> -# CHECK2-NEXT: Other:
>> -# CHECK2-NEXT: Section: .text
>> -# CHECK2-NEXT: }
>> -# CHECK2-NEXT: Symbol {
>> -# CHECK2-NEXT: Name: baz
>> -# CHECK2-NEXT: Value:
>> -# CHECK2-NEXT: Size:
>> -# CHECK2-NEXT: Binding: Global
>> -# CHECK2-NEXT: Type:
>> -# CHECK2-NEXT: Other:
>> -# CHECK2-NEXT: Section: Undefined
>> -# CHECK2-NEXT: }
>> -# CHECK2-NEXT: ]
>> -
>> -# CHECK2-NOT: NEEDED
>> -# CHECK2: NEEDED Shared library: [{{.*}}3.so]
>> -# CHECK2-NOT: NEEDED
>> -
>> .section .text.foo, "ax"
>> .globl foo
>> foo:
>> @@ -134,10 +75,8 @@ ret
>>
>> .section .text._start, "ax"
>> .globl _start
>> -.weak qux
>> _start:
>> call baz
>> -call qux
>> ret
>>
>> .section .text.unused, "ax"
>>
>>
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