forked from OSchip/llvm-project
Make addReservedSymbols a static helper. NFC.
llvm-svn: 320175
This commit is contained in:
Rafael Espindola
parent
ad840d2206
commit
1dd30ddd45
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@ -49,7 +49,6 @@ private:
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void createSyntheticSections();
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void copyLocalSymbols();
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void addSectionSymbols();
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void addReservedSymbols();
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void forEachRelSec(std::function<void(InputSectionBase &)> Fn);
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void sortSections();
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void sortInputSections();
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@ -158,6 +157,83 @@ template <class ELFT> static void combineEhFrameSections() {
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V.erase(std::remove(V.begin(), V.end(), nullptr), V.end());
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}
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template <class ELFT>
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static Defined *addOptionalRegular(StringRef Name, SectionBase *Sec,
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uint64_t Val, uint8_t StOther = STV_HIDDEN,
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uint8_t Binding = STB_GLOBAL) {
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Symbol *S = Symtab->find(Name);
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if (!S || S->isDefined())
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return nullptr;
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Symbol *Sym = Symtab->addRegular<ELFT>(Name, StOther, STT_NOTYPE, Val,
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/*Size=*/0, Binding, Sec,
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/*File=*/nullptr);
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return cast<Defined>(Sym);
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}
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// The linker is expected to define some symbols depending on
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// the linking result. This function defines such symbols.
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template <class ELFT> static void addReservedSymbols() {
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if (Config->EMachine == EM_MIPS) {
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// Define _gp for MIPS. st_value of _gp symbol will be updated by Writer
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// so that it points to an absolute address which by default is relative
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// to GOT. Default offset is 0x7ff0.
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// See "Global Data Symbols" in Chapter 6 in the following document:
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// ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
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ElfSym::MipsGp = Symtab->addAbsolute<ELFT>("_gp", STV_HIDDEN, STB_GLOBAL);
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// On MIPS O32 ABI, _gp_disp is a magic symbol designates offset between
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// start of function and 'gp' pointer into GOT.
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if (Symtab->find("_gp_disp"))
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ElfSym::MipsGpDisp =
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Symtab->addAbsolute<ELFT>("_gp_disp", STV_HIDDEN, STB_GLOBAL);
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// The __gnu_local_gp is a magic symbol equal to the current value of 'gp'
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// pointer. This symbol is used in the code generated by .cpload pseudo-op
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// in case of using -mno-shared option.
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// https://sourceware.org/ml/binutils/2004-12/msg00094.html
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if (Symtab->find("__gnu_local_gp"))
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ElfSym::MipsLocalGp =
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Symtab->addAbsolute<ELFT>("__gnu_local_gp", STV_HIDDEN, STB_GLOBAL);
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}
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// The _GLOBAL_OFFSET_TABLE_ symbol is defined by target convention to
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// be at some offset from the base of the .got section, usually 0 or the end
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// of the .got
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InputSection *GotSection = InX::MipsGot ? cast<InputSection>(InX::MipsGot)
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: cast<InputSection>(InX::Got);
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ElfSym::GlobalOffsetTable = addOptionalRegular<ELFT>(
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"_GLOBAL_OFFSET_TABLE_", GotSection, Target->GotBaseSymOff);
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// __ehdr_start is the location of ELF file headers. Note that we define
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// this symbol unconditionally even when using a linker script, which
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// differs from the behavior implemented by GNU linker which only define
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// this symbol if ELF headers are in the memory mapped segment.
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// __executable_start is not documented, but the expectation of at
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// least the android libc is that it points to the elf header too.
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// __dso_handle symbol is passed to cxa_finalize as a marker to identify
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// each DSO. The address of the symbol doesn't matter as long as they are
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// different in different DSOs, so we chose the start address of the DSO.
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for (const char *Name :
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{"__ehdr_start", "__executable_start", "__dso_handle"})
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addOptionalRegular<ELFT>(Name, Out::ElfHeader, 0, STV_HIDDEN);
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// If linker script do layout we do not need to create any standart symbols.
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if (Script->HasSectionsCommand)
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return;
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auto Add = [](StringRef S, int64_t Pos) {
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return addOptionalRegular<ELFT>(S, Out::ElfHeader, Pos, STV_DEFAULT);
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};
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ElfSym::Bss = Add("__bss_start", 0);
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ElfSym::End1 = Add("end", -1);
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ElfSym::End2 = Add("_end", -1);
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ElfSym::Etext1 = Add("etext", -1);
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ElfSym::Etext2 = Add("_etext", -1);
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ElfSym::Edata1 = Add("edata", -1);
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ElfSym::Edata2 = Add("_edata", -1);
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}
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// The main function of the writer.
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template <class ELFT> void Writer<ELFT>::run() {
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// Create linker-synthesized sections such as .got or .plt.
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@ -169,7 +245,7 @@ template <class ELFT> void Writer<ELFT>::run() {
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// We need to create some reserved symbols such as _end. Create them.
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if (!Config->Relocatable)
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addReservedSymbols();
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addReservedSymbols<ELFT>();
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// We want to process linker script commands. When SECTIONS command
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// is given we let it create sections.
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@ -750,19 +826,6 @@ void PhdrEntry::add(OutputSection *Sec) {
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Sec->PtLoad = this;
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}
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template <class ELFT>
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static Defined *addOptionalRegular(StringRef Name, SectionBase *Sec,
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uint64_t Val, uint8_t StOther = STV_HIDDEN,
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uint8_t Binding = STB_GLOBAL) {
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Symbol *S = Symtab->find(Name);
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if (!S || S->isDefined())
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return nullptr;
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Symbol *Sym = Symtab->addRegular<ELFT>(Name, StOther, STT_NOTYPE, Val,
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/*Size=*/0, Binding, Sec,
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/*File=*/nullptr);
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return cast<Defined>(Sym);
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}
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// The beginning and the ending of .rel[a].plt section are marked
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// with __rel[a]_iplt_{start,end} symbols if it is a statically linked
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// executable. The runtime needs these symbols in order to resolve
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@ -779,70 +842,6 @@ template <class ELFT> void Writer<ELFT>::addRelIpltSymbols() {
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addOptionalRegular<ELFT>(S, In<ELFT>::RelaIplt, -1, STV_HIDDEN, STB_WEAK);
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}
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// The linker is expected to define some symbols depending on
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// the linking result. This function defines such symbols.
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template <class ELFT> void Writer<ELFT>::addReservedSymbols() {
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if (Config->EMachine == EM_MIPS) {
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// Define _gp for MIPS. st_value of _gp symbol will be updated by Writer
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// so that it points to an absolute address which by default is relative
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// to GOT. Default offset is 0x7ff0.
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// See "Global Data Symbols" in Chapter 6 in the following document:
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// ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
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ElfSym::MipsGp = Symtab->addAbsolute<ELFT>("_gp", STV_HIDDEN, STB_GLOBAL);
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// On MIPS O32 ABI, _gp_disp is a magic symbol designates offset between
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// start of function and 'gp' pointer into GOT.
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if (Symtab->find("_gp_disp"))
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ElfSym::MipsGpDisp =
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Symtab->addAbsolute<ELFT>("_gp_disp", STV_HIDDEN, STB_GLOBAL);
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// The __gnu_local_gp is a magic symbol equal to the current value of 'gp'
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// pointer. This symbol is used in the code generated by .cpload pseudo-op
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// in case of using -mno-shared option.
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// https://sourceware.org/ml/binutils/2004-12/msg00094.html
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if (Symtab->find("__gnu_local_gp"))
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ElfSym::MipsLocalGp =
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Symtab->addAbsolute<ELFT>("__gnu_local_gp", STV_HIDDEN, STB_GLOBAL);
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}
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// The _GLOBAL_OFFSET_TABLE_ symbol is defined by target convention to
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// be at some offset from the base of the .got section, usually 0 or the end
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// of the .got
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InputSection *GotSection = InX::MipsGot ? cast<InputSection>(InX::MipsGot)
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: cast<InputSection>(InX::Got);
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ElfSym::GlobalOffsetTable = addOptionalRegular<ELFT>(
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"_GLOBAL_OFFSET_TABLE_", GotSection, Target->GotBaseSymOff);
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// __ehdr_start is the location of ELF file headers. Note that we define
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// this symbol unconditionally even when using a linker script, which
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// differs from the behavior implemented by GNU linker which only define
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// this symbol if ELF headers are in the memory mapped segment.
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// __executable_start is not documented, but the expectation of at
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// least the android libc is that it points to the elf header too.
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// __dso_handle symbol is passed to cxa_finalize as a marker to identify
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// each DSO. The address of the symbol doesn't matter as long as they are
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// different in different DSOs, so we chose the start address of the DSO.
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for (const char *Name :
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{"__ehdr_start", "__executable_start", "__dso_handle"})
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addOptionalRegular<ELFT>(Name, Out::ElfHeader, 0, STV_HIDDEN);
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// If linker script do layout we do not need to create any standart symbols.
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if (Script->HasSectionsCommand)
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return;
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auto Add = [](StringRef S, int64_t Pos) {
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return addOptionalRegular<ELFT>(S, Out::ElfHeader, Pos, STV_DEFAULT);
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};
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ElfSym::Bss = Add("__bss_start", 0);
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ElfSym::End1 = Add("end", -1);
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ElfSym::End2 = Add("_end", -1);
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ElfSym::Etext1 = Add("etext", -1);
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ElfSym::Etext2 = Add("_etext", -1);
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ElfSym::Edata1 = Add("edata", -1);
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ElfSym::Edata2 = Add("_edata", -1);
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}
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template <class ELFT>
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void Writer<ELFT>::forEachRelSec(std::function<void(InputSectionBase &)> Fn) {
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// Scan all relocations. Each relocation goes through a series
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