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Moves needsPlt to Writer.cpp. 

It was only used there.

llvm-svn: 267002
This commit is contained in:
Rafael Espindola 2016-04-21 16:57:32 +00:00
parent 358efd6557
commit 0c869a752e
3 changed files with 55 additions and 55 deletions
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60
lld/ELF/Target.cpp
View File

@ -84,7 +84,7 @@ public:
int32_t Index, unsigned RelOff) const override;
bool isRelRelative(uint32_t Type) const override;
bool needsCopyRelImpl(uint32_t Type) const override;
bool needsPltImpl(uint32_t Type) const override;
bool needsPlt(uint32_t Type) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
@ -108,7 +108,7 @@ public:
void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
bool needsCopyRelImpl(uint32_t Type) const override;
bool needsPltImpl(uint32_t Type) const override;
bool needsPlt(uint32_t Type) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
bool isRelRelative(uint32_t Type) const override;
@ -132,7 +132,7 @@ public:
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override;
void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
bool needsPltImpl(uint32_t Type) const override;
bool needsPlt(uint32_t Type) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
bool isRelRelative(uint32_t Type) const override;
};
@ -151,7 +151,7 @@ public:
uint32_t getTlsGotRel(uint32_t Type) const override;
bool isRelRelative(uint32_t Type) const override;
bool needsCopyRelImpl(uint32_t Type) const override;
bool needsPltImpl(uint32_t Type) const override;
bool needsPlt(uint32_t Type) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
@ -180,7 +180,7 @@ public:
void writeGotHeader(uint8_t *Buf) const override;
void writeThunk(uint8_t *Buf, uint64_t S) const override;
bool needsCopyRelImpl(uint32_t Type) const override;
bool needsPltImpl(uint32_t Type) const override;
bool needsPlt(uint32_t Type) const override;
bool needsThunk(uint32_t Type, const InputFile &File,
const SymbolBody &S) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
@ -244,44 +244,7 @@ bool TargetInfo::needsCopyRel(uint32_t Type, const SymbolBody &S) const {
bool TargetInfo::isHintRel(uint32_t Type) const { return false; }
bool TargetInfo::isRelRelative(uint32_t Type) const { return true; }
bool TargetInfo::needsPltImpl(uint32_t Type) const { return false; }
TargetInfo::PltNeed TargetInfo::needsPlt(uint32_t Type,
const SymbolBody &S) const {
if (S.isGnuIFunc())
return Plt_Explicit;
if (S.isPreemptible() && needsPltImpl(Type))
return Plt_Explicit;
// This handles a non PIC program call to function in a shared library.
// In an ideal world, we could just report an error saying the relocation
// can overflow at runtime.
// In the real world with glibc, crt1.o has a R_X86_64_PC32 pointing to
// libc.so.
//
// The general idea on how to handle such cases is to create a PLT entry
// and use that as the function value.
//
// For the static linking part, we just return true and everything else
// will use the the PLT entry as the address.
//
// The remaining problem is making sure pointer equality still works. We
// need the help of the dynamic linker for that. We let it know that we have
// a direct reference to a so symbol by creating an undefined symbol with a
// non zero st_value. Seeing that, the dynamic linker resolves the symbol to
// the value of the symbol we created. This is true even for got entries, so
// pointer equality is maintained. To avoid an infinite loop, the only entry
// that points to the real function is a dedicated got entry used by the
// plt. That is identified by special relocation types (R_X86_64_JUMP_SLOT,
// R_386_JMP_SLOT, etc).
if (S.isShared() && !Config->Pic && S.isFunc()) {
RelExpr Expr = getRelExpr(Type, S);
if (!refersToGotEntry(Expr))
return Plt_Implicit;
}
return Plt_No;
}
bool TargetInfo::needsPlt(uint32_t Type) const { return false; }
bool TargetInfo::needsThunk(uint32_t Type, const InputFile &File,
const SymbolBody &S) const {
@ -452,7 +415,7 @@ bool X86TargetInfo::needsCopyRelImpl(uint32_t Type) const {
return Type == R_386_32 || Type == R_386_16 || Type == R_386_8;
}
bool X86TargetInfo::needsPltImpl(uint32_t Type) const {
bool X86TargetInfo::needsPlt(uint32_t Type) const {
return Type == R_386_PLT32;
}
@ -691,7 +654,7 @@ bool X86_64TargetInfo::isTlsLocalDynamicRel(uint32_t Type) const {
Type == R_X86_64_TLSLD;
}
bool X86_64TargetInfo::needsPltImpl(uint32_t Type) const {
bool X86_64TargetInfo::needsPlt(uint32_t Type) const {
return Type == R_X86_64_PLT32;
}
@ -954,7 +917,7 @@ void PPC64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr,
write32be(Buf + 28, 0x4e800420); // bctr
}
bool PPC64TargetInfo::needsPltImpl(uint32_t Type) const {
bool PPC64TargetInfo::needsPlt(uint32_t Type) const {
// These are function calls that need to be redirected through a PLT stub.
return Type == R_PPC64_REL24;
}
@ -1222,7 +1185,7 @@ bool AArch64TargetInfo::needsCopyRelImpl(uint32_t Type) const {
}
}
bool AArch64TargetInfo::needsPltImpl(uint32_t Type) const {
bool AArch64TargetInfo::needsPlt(uint32_t Type) const {
switch (Type) {
default:
return false;
@ -1593,8 +1556,7 @@ bool MipsTargetInfo<ELFT>::needsCopyRelImpl(uint32_t Type) const {
return !isRelRelative(Type) || Type == R_MIPS_LO16;
}
template <class ELFT>
bool MipsTargetInfo<ELFT>::needsPltImpl(uint32_t Type) const {
template <class ELFT> bool MipsTargetInfo<ELFT>::needsPlt(uint32_t Type) const {
return Type == R_MIPS_26;
}

6
lld/ELF/Target.h
View File

@ -55,9 +55,6 @@ public:
// dynamic linker if isRelRelative returns true.
virtual bool isRelRelative(uint32_t Type) const;
enum PltNeed { Plt_No, Plt_Explicit, Plt_Implicit };
PltNeed needsPlt(uint32_t Type, const SymbolBody &S) const;
virtual bool needsThunk(uint32_t Type, const InputFile &File,
const SymbolBody &S) const;
@ -100,9 +97,10 @@ public:
virtual void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
virtual void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
virtual bool needsPlt(uint32_t Type) const;
private:
virtual bool needsCopyRelImpl(uint32_t Type) const;
virtual bool needsPltImpl(uint32_t Type) const;
};
uint64_t getPPC64TocBase();

44
lld/ELF/Writer.cpp
View File

@ -431,6 +431,46 @@ template <class ELFT> static bool isAbsolute(const SymbolBody &Body) {
return false;
}
namespace {
enum PltNeed { Plt_No, Plt_Explicit, Plt_Implicit };
}
static PltNeed needsPlt(uint32_t Type, const SymbolBody &S) {
if (S.isGnuIFunc())
return Plt_Explicit;
if (S.isPreemptible() && Target->needsPlt(Type))
return Plt_Explicit;
// This handles a non PIC program call to function in a shared library.
// In an ideal world, we could just report an error saying the relocation
// can overflow at runtime.
// In the real world with glibc, crt1.o has a R_X86_64_PC32 pointing to
// libc.so.
//
// The general idea on how to handle such cases is to create a PLT entry
// and use that as the function value.
//
// For the static linking part, we just return true and everything else
// will use the the PLT entry as the address.
//
// The remaining problem is making sure pointer equality still works. We
// need the help of the dynamic linker for that. We let it know that we have
// a direct reference to a so symbol by creating an undefined symbol with a
// non zero st_value. Seeing that, the dynamic linker resolves the symbol to
// the value of the symbol we created. This is true even for got entries, so
// pointer equality is maintained. To avoid an infinite loop, the only entry
// that points to the real function is a dedicated got entry used by the
// plt. That is identified by special relocation types (R_X86_64_JUMP_SLOT,
// R_386_JMP_SLOT, etc).
if (S.isShared() && !Config->Pic && S.isFunc()) {
RelExpr Expr = Target->getRelExpr(Type, S);
if (!refersToGotEntry(Expr))
return Plt_Implicit;
}
return Plt_No;
}
// The reason we have to do this early scan is as follows
// * To mmap the output file, we need to know the size
// * For that, we need to know how many dynamic relocs we will have.
@ -528,9 +568,9 @@ void Writer<ELFT>::scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
// If a relocation needs PLT, we create a PLT and a GOT slot
// for the symbol.
TargetInfo::PltNeed NeedPlt = Target->needsPlt(Type, Body);
PltNeed NeedPlt = needsPlt(Type, Body);
if (NeedPlt) {
if (NeedPlt == TargetInfo::Plt_Implicit)
if (NeedPlt == Plt_Implicit)
Body.NeedsCopyOrPltAddr = true;
RelExpr E;
if (Expr == R_PPC_OPD)