[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 10:06:17 PST 2017
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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