[lld] r266208 - ELF: Use hidden visibility for all DefinedSynthetic symbols.
Rafael Espíndola via llvm-commits
llvm-commits at lists.llvm.org
Wed Apr 13 13:05:51 PDT 2016
awesome, thanks!
On 13 April 2016 at 12:57, Peter Collingbourne via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: pcc
> Date: Wed Apr 13 11:57:28 2016
> New Revision: 266208
>
> URL: http://llvm.org/viewvc/llvm-project?rev=266208&view=rev
> Log:
> ELF: Use hidden visibility for all DefinedSynthetic symbols.
>
> This simplifies the code by allowing us to remove the visibility argument
> to functions that create synthetic symbols.
>
> The only functional change is that the visibility of the MIPS "_gp" symbol
> is now hidden. Because this symbol is defined in every executable or DSO, it
> would be difficult to observe a visibility change here.
>
> Differential Revision: http://reviews.llvm.org/D19033
>
> Modified:
> lld/trunk/ELF/SymbolTable.cpp
> lld/trunk/ELF/SymbolTable.h
> lld/trunk/ELF/Symbols.cpp
> lld/trunk/ELF/Symbols.h
> lld/trunk/ELF/Writer.cpp
> lld/trunk/test/ELF/basic-mips.s
> lld/trunk/test/ELF/mips-dynamic.s
> lld/trunk/test/ELF/mips-got-relocs.s
> lld/trunk/test/ELF/mips-gp-disp.s
> lld/trunk/test/ELF/mips-gp-local.s
> lld/trunk/test/ELF/mips-gprel32-relocs-gp0.test
> lld/trunk/test/ELF/mips-gprel32-relocs.s
> lld/trunk/test/ELF/mips-hilo-gp-disp.s
>
> Modified: lld/trunk/ELF/SymbolTable.cpp
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.cpp?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/ELF/SymbolTable.cpp (original)
> +++ lld/trunk/ELF/SymbolTable.cpp Wed Apr 13 11:57:28 2016
> @@ -161,8 +161,8 @@ DefinedRegular<ELFT> *SymbolTable<ELFT>:
> template <class ELFT>
> SymbolBody *SymbolTable<ELFT>::addSynthetic(StringRef Name,
> OutputSectionBase<ELFT> &Sec,
> - uintX_t Val, uint8_t Visibility) {
> - auto *Sym = new (Alloc) DefinedSynthetic<ELFT>(Name, Val, Sec, Visibility);
> + uintX_t Val) {
> + auto *Sym = new (Alloc) DefinedSynthetic<ELFT>(Name, Val, Sec);
> resolve(Sym);
> return Sym;
> }
>
> Modified: lld/trunk/ELF/SymbolTable.h
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.h?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/ELF/SymbolTable.h (original)
> +++ lld/trunk/ELF/SymbolTable.h Wed Apr 13 11:57:28 2016
> @@ -55,7 +55,7 @@ public:
> DefinedRegular<ELFT> *addAbsolute(StringRef Name,
> uint8_t Visibility = llvm::ELF::STV_HIDDEN);
> SymbolBody *addSynthetic(StringRef Name, OutputSectionBase<ELFT> &Section,
> - uintX_t Value, uint8_t Visibility);
> + uintX_t Value);
> DefinedRegular<ELFT> *addIgnored(StringRef Name,
> uint8_t Visibility = llvm::ELF::STV_HIDDEN);
>
>
> Modified: lld/trunk/ELF/Symbols.cpp
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Symbols.cpp?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/ELF/Symbols.cpp (original)
> +++ lld/trunk/ELF/Symbols.cpp Wed Apr 13 11:57:28 2016
> @@ -296,9 +296,8 @@ UndefinedElf<ELFT>::UndefinedElf(const E
>
> template <typename ELFT>
> DefinedSynthetic<ELFT>::DefinedSynthetic(StringRef N, uintX_t Value,
> - OutputSectionBase<ELFT> &Section,
> - uint8_t StOther)
> - : Defined(SymbolBody::DefinedSyntheticKind, N, STB_GLOBAL, StOther,
> + OutputSectionBase<ELFT> &Section)
> + : Defined(SymbolBody::DefinedSyntheticKind, N, STB_GLOBAL, STV_HIDDEN,
> 0 /* Type */),
> Value(Value), Section(Section) {}
>
>
> Modified: lld/trunk/ELF/Symbols.h
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Symbols.h?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/ELF/Symbols.h (original)
> +++ lld/trunk/ELF/Symbols.h Wed Apr 13 11:57:28 2016
> @@ -269,8 +269,8 @@ InputSectionBase<ELFT> *DefinedRegular<E
> template <class ELFT> class DefinedSynthetic : public Defined {
> public:
> typedef typename ELFT::uint uintX_t;
> - DefinedSynthetic(StringRef N, uintX_t Value, OutputSectionBase<ELFT> &Section,
> - uint8_t StOther);
> + DefinedSynthetic(StringRef N, uintX_t Value,
> + OutputSectionBase<ELFT> &Section);
>
> static bool classof(const SymbolBody *S) {
> return S->kind() == SymbolBody::DefinedSyntheticKind;
>
> Modified: lld/trunk/ELF/Writer.cpp
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/ELF/Writer.cpp (original)
> +++ lld/trunk/ELF/Writer.cpp Wed Apr 13 11:57:28 2016
> @@ -932,11 +932,10 @@ bool Writer<ELFT>::isDiscarded(InputSect
> template <class ELFT>
> static SymbolBody *
> addOptionalSynthetic(SymbolTable<ELFT> &Table, StringRef Name,
> - OutputSectionBase<ELFT> &Sec, typename ELFT::uint Val,
> - uint8_t Visibility) {
> + OutputSectionBase<ELFT> &Sec, typename ELFT::uint Val) {
> if (!Table.find(Name))
> return nullptr;
> - return Table.addSynthetic(Name, Sec, Val, Visibility);
> + return Table.addSynthetic(Name, Sec, Val);
> }
>
> // The beginning and the ending of .rel[a].plt section are marked
> @@ -951,12 +950,11 @@ void Writer<ELFT>::addRelIpltSymbols() {
> return;
> StringRef S = Config->Rela ? "__rela_iplt_start" : "__rel_iplt_start";
> ElfSym<ELFT>::RelaIpltStart =
> - addOptionalSynthetic(Symtab, S, *Out<ELFT>::RelaPlt, 0, STV_HIDDEN);
> + addOptionalSynthetic(Symtab, S, *Out<ELFT>::RelaPlt, 0);
>
> S = Config->Rela ? "__rela_iplt_end" : "__rel_iplt_end";
> - ElfSym<ELFT>::RelaIpltEnd =
> - addOptionalSynthetic(Symtab, S, *Out<ELFT>::RelaPlt,
> - DefinedSynthetic<ELFT>::SectionEnd, STV_HIDDEN);
> + ElfSym<ELFT>::RelaIpltEnd = addOptionalSynthetic(
> + Symtab, S, *Out<ELFT>::RelaPlt, DefinedSynthetic<ELFT>::SectionEnd);
> }
>
> template <class ELFT> static bool includeInSymtab(const SymbolBody &B) {
> @@ -1076,18 +1074,18 @@ template <class ELFT> void Writer<ELFT>:
> // See "Global Data Symbols" in Chapter 6 in the following document:
> // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
> ElfSym<ELFT>::MipsGp =
> - Symtab.addSynthetic("_gp", *Out<ELFT>::Got, MipsGPOffset, STV_DEFAULT);
> + Symtab.addSynthetic("_gp", *Out<ELFT>::Got, MipsGPOffset);
>
> // On MIPS O32 ABI, _gp_disp is a magic symbol designates offset between
> // start of function and 'gp' pointer into GOT.
> - ElfSym<ELFT>::MipsGpDisp = addOptionalSynthetic(
> - Symtab, "_gp_disp", *Out<ELFT>::Got, MipsGPOffset, STV_HIDDEN);
> + ElfSym<ELFT>::MipsGpDisp =
> + addOptionalSynthetic(Symtab, "_gp_disp", *Out<ELFT>::Got, MipsGPOffset);
> // The __gnu_local_gp is a magic symbol equal to the current value of 'gp'
> // pointer. This symbol is used in the code generated by .cpload pseudo-op
> // in case of using -mno-shared option.
> // https://sourceware.org/ml/binutils/2004-12/msg00094.html
> ElfSym<ELFT>::MipsLocalGp = addOptionalSynthetic(
> - Symtab, "__gnu_local_gp", *Out<ELFT>::Got, MipsGPOffset, STV_HIDDEN);
> + Symtab, "__gnu_local_gp", *Out<ELFT>::Got, MipsGPOffset);
> }
>
> // In the assembly for 32 bit x86 the _GLOBAL_OFFSET_TABLE_ symbol
> @@ -1213,7 +1211,7 @@ template <class ELFT> void Writer<ELFT>:
> // Even the author of gold doesn't remember why gold behaves that way.
> // https://sourceware.org/ml/binutils/2002-03/msg00360.html
> if (isOutputDynamic())
> - Symtab.addSynthetic("_DYNAMIC", *Out<ELFT>::Dynamic, 0, STV_HIDDEN);
> + Symtab.addSynthetic("_DYNAMIC", *Out<ELFT>::Dynamic, 0);
>
> // Define __rel[a]_iplt_{start,end} symbols if needed.
> addRelIpltSymbols();
> @@ -1363,9 +1361,8 @@ template <class ELFT> void Writer<ELFT>:
> auto Define = [&](StringRef Start, StringRef End,
> OutputSectionBase<ELFT> *OS) {
> if (OS) {
> - Symtab.addSynthetic(Start, *OS, 0, STV_HIDDEN);
> - Symtab.addSynthetic(End, *OS, DefinedSynthetic<ELFT>::SectionEnd,
> - STV_HIDDEN);
> + Symtab.addSynthetic(Start, *OS, 0);
> + Symtab.addSynthetic(End, *OS, DefinedSynthetic<ELFT>::SectionEnd);
> } else {
> Symtab.addIgnored(Start);
> Symtab.addIgnored(End);
> @@ -1395,11 +1392,10 @@ void Writer<ELFT>::addStartStopSymbols(O
> StringRef Stop = Saver.save("__stop_" + S);
> if (SymbolBody *B = Symtab.find(Start))
> if (B->isUndefined())
> - Symtab.addSynthetic(Start, *Sec, 0, STV_HIDDEN);
> + Symtab.addSynthetic(Start, *Sec, 0);
> if (SymbolBody *B = Symtab.find(Stop))
> if (B->isUndefined())
> - Symtab.addSynthetic(Stop, *Sec, DefinedSynthetic<ELFT>::SectionEnd,
> - STV_HIDDEN);
> + Symtab.addSynthetic(Stop, *Sec, DefinedSynthetic<ELFT>::SectionEnd);
> }
>
> template <class ELFT> static bool needsPtLoad(OutputSectionBase<ELFT> *Sec) {
>
> Modified: lld/trunk/test/ELF/basic-mips.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/basic-mips.s?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/basic-mips.s (original)
> +++ lld/trunk/test/ELF/basic-mips.s Wed Apr 13 11:57:28 2016
> @@ -204,22 +204,24 @@ __start:
> # CHECK-NEXT: Section: Undefined (0x0)
> # CHECK-NEXT: }
> # CHECK-NEXT: Symbol {
> -# CHECK-NEXT: Name: __start
> -# CHECK-NEXT: Value: 0x20000
> +# CHECK-NEXT: Name: _gp
> +# CHECK-NEXT: Value: 0x37FF0
> # CHECK-NEXT: Size: 0
> -# CHECK-NEXT: Binding: Global (0x1)
> +# CHECK-NEXT: Binding: Local
> # CHECK-NEXT: Type: None (0x0)
> -# CHECK-NEXT: Other: 0
> -# CHECK-NEXT: Section: .text
> +# CHECK-NEXT: Other [ (0x2)
> +# CHECK-NEXT: STV_HIDDEN (0x2)
> +# CHECK-NEXT: ]
> +# CHECK-NEXT: Section: .got
> # CHECK-NEXT: }
> # CHECK-NEXT: Symbol {
> -# CHECK-NEXT: Name: _gp
> -# CHECK-NEXT: Value: 0x37FF0
> +# CHECK-NEXT: Name: __start
> +# CHECK-NEXT: Value: 0x20000
> # CHECK-NEXT: Size: 0
> -# CHECK-NEXT: Binding: Global
> +# CHECK-NEXT: Binding: Global (0x1)
> # CHECK-NEXT: Type: None (0x0)
> # CHECK-NEXT: Other: 0
> -# CHECK-NEXT: Section: .got
> +# CHECK-NEXT: Section: .text
> # CHECK-NEXT: }
> # CHECK-NEXT: ]
> # CHECK-NEXT: ProgramHeaders [
>
> Modified: lld/trunk/test/ELF/mips-dynamic.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-dynamic.s?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/mips-dynamic.s (original)
> +++ lld/trunk/test/ELF/mips-dynamic.s Wed Apr 13 11:57:28 2016
> @@ -47,8 +47,8 @@
> # EXE-DAG: 0x70000005 MIPS_FLAGS NOTPOT
> # EXE-DAG: 0x70000006 MIPS_BASE_ADDRESS
> # EXE-DAG: 0x7000000A MIPS_LOCAL_GOTNO 2
> -# EXE-DAG: 0x70000011 MIPS_SYMTABNO 3
> -# EXE-DAG: 0x70000013 MIPS_GOTSYM 0x3
> +# EXE-DAG: 0x70000011 MIPS_SYMTABNO 2
> +# EXE-DAG: 0x70000013 MIPS_GOTSYM 0x2
> # EXE-DAG: 0x70000016 MIPS_RLD_MAP [[RLDMAPADDR]]
> # EXE: ]
>
> @@ -73,7 +73,6 @@
> # DSO: Name: @
> # DSO: Name: __start@
> # DSO: Name: _foo@
> -# DSO: Name: _gp@
> # DSO: ]
> # DSO: DynamicSection [
> # DSO-NEXT: Tag Type Name/Value
> @@ -82,8 +81,8 @@
> # DSO-DAG: 0x70000005 MIPS_FLAGS NOTPOT
> # DSO-DAG: 0x70000006 MIPS_BASE_ADDRESS 0x0
> # DSO-DAG: 0x7000000A MIPS_LOCAL_GOTNO 2
> -# DSO-DAG: 0x70000011 MIPS_SYMTABNO 4
> -# DSO-DAG: 0x70000013 MIPS_GOTSYM 0x4
> +# DSO-DAG: 0x70000011 MIPS_SYMTABNO 3
> +# DSO-DAG: 0x70000013 MIPS_GOTSYM 0x3
> # DSO: ]
>
> .text
>
> Modified: lld/trunk/test/ELF/mips-got-relocs.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-got-relocs.s?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/mips-got-relocs.s (original)
> +++ lld/trunk/test/ELF/mips-got-relocs.s Wed Apr 13 11:57:28 2016
> @@ -47,9 +47,9 @@ v1:
> # EXE_SYM: Sections:
> # EXE_SYM: .got 0000000c 0000000000030000 DATA
> # EXE_SYM: SYMBOL TABLE:
> -# EXE_SYM: 00040000 g .data 00000004 v1
> -# EXE_SYM: 00037ff0 .got 00000000 _gp
> +# EXE_SYM: 00037ff0 .got 00000000 .hidden _gp
> # ^-- .got + GP offset (0x7ff0)
> +# EXE_SYM: 00040000 g .data 00000004 v1
>
>
> # EXE_GOT_BE: Contents of section .got:
> @@ -71,9 +71,9 @@ v1:
> # DSO_SYM: Sections:
> # DSO_SYM: .got 0000000c 0000000000020000 DATA
> # DSO_SYM: SYMBOL TABLE:
> -# DSO_SYM: 00030000 g .data 00000004 v1
> -# DSO_SYM: 00027ff0 .got 00000000 _gp
> +# DSO_SYM: 00027ff0 .got 00000000 .hidden _gp
> # ^-- .got + GP offset (0x7ff0)
> +# DSO_SYM: 00030000 g .data 00000004 v1
>
> # DSO_GOT_BE: Contents of section .got:
> # DSO_GOT_BE: 20000 00000000 80000000 00030000
>
> Modified: lld/trunk/test/ELF/mips-gp-disp.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-gp-disp.s?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/mips-gp-disp.s (original)
> +++ lld/trunk/test/ELF/mips-gp-disp.s Wed Apr 13 11:57:28 2016
> @@ -24,7 +24,7 @@
> # DIS-NEXT: 10000: 3c 08 00 01 lui $8, 1
> # DIS-NEXT: 10004: 21 08 7f f0 addi $8, $8, 32752
> # ^-- 0x37ff0 & 0xffff
> -# DIS: 00027ff0 .got 00000000 _gp
> +# DIS: 00027ff0 .got 00000000 .hidden _gp
>
> # REL: Relocations [
> # REL-NEXT: ]
>
> Modified: lld/trunk/test/ELF/mips-gp-local.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-gp-local.s?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/mips-gp-local.s (original)
> +++ lld/trunk/test/ELF/mips-gp-local.s Wed Apr 13 11:57:28 2016
> @@ -11,7 +11,7 @@
> # CHECK-NEXT: 20000: 3c 08 00 03 lui $8, 3
> # CHECK-NEXT: 20004: 21 08 7f f0 addi $8, $8, 32752
>
> -# CHECK: 00037ff0 .got 00000000 _gp
> +# CHECK: 00037ff0 .got 00000000 .hidden _gp
>
> .text
> .globl __start
>
> Modified: lld/trunk/test/ELF/mips-gprel32-relocs-gp0.test
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-gprel32-relocs-gp0.test?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/mips-gprel32-relocs-gp0.test (original)
> +++ lld/trunk/test/ELF/mips-gprel32-relocs-gp0.test Wed Apr 13 11:57:28 2016
> @@ -28,4 +28,4 @@
> # CHECK: SYMBOL TABLE:
> # CHECK: 00010000 .text 00000000 foo
> # CHECK: 00010010 .text 00000000 bar
> -# CHECK: 00027ff0 .got 00000000 _gp
> +# CHECK: 00027ff0 .got 00000000 .hidden _gp
>
> Modified: lld/trunk/test/ELF/mips-gprel32-relocs.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-gprel32-relocs.s?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/mips-gprel32-relocs.s (original)
> +++ lld/trunk/test/ELF/mips-gprel32-relocs.s Wed Apr 13 11:57:28 2016
> @@ -28,4 +28,4 @@ v1:
> # CHECK: SYMBOL TABLE:
> # CHECK: 00010008 .text 00000000 bar
> # CHECK: 00010004 .text 00000000 foo
> -# CHECK: 00027ff0 .got 00000000 _gp
> +# CHECK: 00027ff0 .got 00000000 .hidden _gp
>
> Modified: lld/trunk/test/ELF/mips-hilo-gp-disp.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-hilo-gp-disp.s?rev=266208&r1=266207&r2=266208&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/mips-hilo-gp-disp.s (original)
> +++ lld/trunk/test/ELF/mips-hilo-gp-disp.s Wed Apr 13 11:57:28 2016
> @@ -25,9 +25,9 @@ __start:
> # ^-- %lo(0x37ff0-0x20004+4)
>
> # EXE: SYMBOL TABLE:
> +# EXE: 00037ff0 .got 00000000 .hidden _gp
> # EXE: 00020000 .text 00000000 __start
> # EXE: 00020010 .text 00000000 _foo
> -# EXE: 00037ff0 .got 00000000 _gp
>
> # SO: Disassembly of section .text:
> # SO-NEXT: __start:
> @@ -37,6 +37,6 @@ __start:
> # ^-- %lo(0x27ff0-0x10004+4)
>
> # SO: SYMBOL TABLE:
> +# SO: 00027ff0 .got 00000000 .hidden _gp
> # SO: 00010000 .text 00000000 __start
> # SO: 00010010 .text 00000000 _foo
> -# SO: 00027ff0 .got 00000000 _gp
>
>
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