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diff --git a/gnu/llvm/tools/lld/ELF/Thunks.cpp b/gnu/llvm/tools/lld/ELF/Thunks.cpp
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-//===- Thunks.cpp --------------------------------------------------------===//
-//
-// The LLVM Linker
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===---------------------------------------------------------------------===//
-//
-// This file contains Thunk subclasses.
-//
-// A thunk is a small piece of code written after an input section
-// which is used to jump between "incompatible" functions
-// such as MIPS PIC and non-PIC or ARM non-Thumb and Thumb functions.
-//
-// If a jump target is too far and its address doesn't fit to a
-// short jump instruction, we need to create a thunk too, but we
-// haven't supported it yet.
-//
-// i386 and x86-64 don't need thunks.
-//
-//===---------------------------------------------------------------------===//
-
-#include "Thunks.h"
-#include "Config.h"
-#include "InputSection.h"
-#include "OutputSections.h"
-#include "Symbols.h"
-#include "SyntheticSections.h"
-#include "Target.h"
-#include "lld/Common/ErrorHandler.h"
-#include "lld/Common/Memory.h"
-#include "llvm/BinaryFormat/ELF.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Endian.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/MathExtras.h"
-#include <cstdint>
-#include <cstring>
-
-using namespace llvm;
-using namespace llvm::object;
-using namespace llvm::ELF;
-
-namespace lld {
-namespace elf {
-
-namespace {
-
-// AArch64 long range Thunks
-class AArch64ABSLongThunk final : public Thunk {
-public:
- AArch64ABSLongThunk(Symbol &Dest) : Thunk(Dest) {}
- uint32_t size() override { return 16; }
- void writeTo(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-class AArch64ADRPThunk final : public Thunk {
-public:
- AArch64ADRPThunk(Symbol &Dest) : Thunk(Dest) {}
- uint32_t size() override { return 12; }
- void writeTo(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-// Base class for ARM thunks.
-//
-// An ARM thunk may be either short or long. A short thunk is simply a branch
-// (B) instruction, and it may be used to call ARM functions when the distance
-// from the thunk to the target is less than 32MB. Long thunks can branch to any
-// virtual address and can switch between ARM and Thumb, and they are
-// implemented in the derived classes. This class tries to create a short thunk
-// if the target is in range, otherwise it creates a long thunk.
-class ARMThunk : public Thunk {
-public:
- ARMThunk(Symbol &Dest) : Thunk(Dest) {}
-
- bool mayUseShortThunk();
- uint32_t size() override { return mayUseShortThunk() ? 4 : sizeLong(); }
- void writeTo(uint8_t *Buf) override;
- bool isCompatibleWith(RelType Type) const override;
-
- // Returns the size of a long thunk.
- virtual uint32_t sizeLong() = 0;
-
- // Writes a long thunk to Buf.
- virtual void writeLong(uint8_t *Buf) = 0;
-
-private:
- // This field tracks whether all previously considered layouts would allow
- // this thunk to be short. If we have ever needed a long thunk, we always
- // create a long thunk, even if the thunk may be short given the current
- // distance to the target. We do this because transitioning from long to short
- // can create layout oscillations in certain corner cases which would prevent
- // the layout from converging.
- bool MayUseShortThunk = true;
-};
-
-// Base class for Thumb-2 thunks.
-//
-// This class is similar to ARMThunk, but it uses the Thumb-2 B.W instruction
-// which has a range of 16MB.
-class ThumbThunk : public Thunk {
-public:
- ThumbThunk(Symbol &Dest) : Thunk(Dest) { Alignment = 2; }
-
- bool mayUseShortThunk();
- uint32_t size() override { return mayUseShortThunk() ? 4 : sizeLong(); }
- void writeTo(uint8_t *Buf) override;
- bool isCompatibleWith(RelType Type) const override;
-
- // Returns the size of a long thunk.
- virtual uint32_t sizeLong() = 0;
-
- // Writes a long thunk to Buf.
- virtual void writeLong(uint8_t *Buf) = 0;
-
-private:
- // See comment in ARMThunk above.
- bool MayUseShortThunk = true;
-};
-
-// Specific ARM Thunk implementations. The naming convention is:
-// Source State, TargetState, Target Requirement, ABS or PI, Range
-class ARMV7ABSLongThunk final : public ARMThunk {
-public:
- ARMV7ABSLongThunk(Symbol &Dest) : ARMThunk(Dest) {}
-
- uint32_t sizeLong() override { return 12; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-class ARMV7PILongThunk final : public ARMThunk {
-public:
- ARMV7PILongThunk(Symbol &Dest) : ARMThunk(Dest) {}
-
- uint32_t sizeLong() override { return 16; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-class ThumbV7ABSLongThunk final : public ThumbThunk {
-public:
- ThumbV7ABSLongThunk(Symbol &Dest) : ThumbThunk(Dest) {}
-
- uint32_t sizeLong() override { return 10; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-class ThumbV7PILongThunk final : public ThumbThunk {
-public:
- ThumbV7PILongThunk(Symbol &Dest) : ThumbThunk(Dest) {}
-
- uint32_t sizeLong() override { return 12; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-// Implementations of Thunks for older Arm architectures that do not support
-// the movt/movw instructions. These thunks require at least Architecture v5
-// as used on processors such as the Arm926ej-s. There are no Thumb entry
-// points as there is no Thumb branch instruction on these architecture that
-// can result in a thunk
-class ARMV5ABSLongThunk final : public ARMThunk {
-public:
- ARMV5ABSLongThunk(Symbol &Dest) : ARMThunk(Dest) {}
-
- uint32_t sizeLong() override { return 8; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
- bool isCompatibleWith(uint32_t RelocType) const override;
-};
-
-class ARMV5PILongThunk final : public ARMThunk {
-public:
- ARMV5PILongThunk(Symbol &Dest) : ARMThunk(Dest) {}
-
- uint32_t sizeLong() override { return 16; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
- bool isCompatibleWith(uint32_t RelocType) const override;
-};
-
-// Implementations of Thunks for Arm v6-M. Only Thumb instructions are permitted
-class ThumbV6MABSLongThunk final : public ThumbThunk {
-public:
- ThumbV6MABSLongThunk(Symbol &Dest) : ThumbThunk(Dest) {}
-
- uint32_t sizeLong() override { return 12; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-class ThumbV6MPILongThunk final : public ThumbThunk {
-public:
- ThumbV6MPILongThunk(Symbol &Dest) : ThumbThunk(Dest) {}
-
- uint32_t sizeLong() override { return 16; }
- void writeLong(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-// MIPS LA25 thunk
-class MipsThunk final : public Thunk {
-public:
- MipsThunk(Symbol &Dest) : Thunk(Dest) {}
-
- uint32_t size() override { return 16; }
- void writeTo(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
- InputSection *getTargetInputSection() const override;
-};
-
-// microMIPS R2-R5 LA25 thunk
-class MicroMipsThunk final : public Thunk {
-public:
- MicroMipsThunk(Symbol &Dest) : Thunk(Dest) {}
-
- uint32_t size() override { return 14; }
- void writeTo(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
- InputSection *getTargetInputSection() const override;
-};
-
-// microMIPS R6 LA25 thunk
-class MicroMipsR6Thunk final : public Thunk {
-public:
- MicroMipsR6Thunk(Symbol &Dest) : Thunk(Dest) {}
-
- uint32_t size() override { return 12; }
- void writeTo(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
- InputSection *getTargetInputSection() const override;
-};
-
-
-// PPC64 Plt call stubs.
-// Any call site that needs to call through a plt entry needs a call stub in
-// the .text section. The call stub is responsible for:
-// 1) Saving the toc-pointer to the stack.
-// 2) Loading the target functions address from the procedure linkage table into
-// r12 for use by the target functions global entry point, and into the count
-// register.
-// 3) Transfering control to the target function through an indirect branch.
-class PPC64PltCallStub final : public Thunk {
-public:
- PPC64PltCallStub(Symbol &Dest) : Thunk(Dest) {}
- uint32_t size() override { return 20; }
- void writeTo(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-};
-
-// A bl instruction uses a signed 24 bit offset, with an implicit 4 byte
-// alignment. This gives a possible 26 bits of 'reach'. If the call offset is
-// larger then that we need to emit a long-branch thunk. The target address
-// of the callee is stored in a table to be accessed TOC-relative. Since the
-// call must be local (a non-local call will have a PltCallStub instead) the
-// table stores the address of the callee's local entry point. For
-// position-independent code a corresponding relative dynamic relocation is
-// used.
-class PPC64LongBranchThunk : public Thunk {
-public:
- uint32_t size() override { return 16; }
- void writeTo(uint8_t *Buf) override;
- void addSymbols(ThunkSection &IS) override;
-
-protected:
- PPC64LongBranchThunk(Symbol &Dest) : Thunk(Dest) {}
-};
-
-class PPC64PILongBranchThunk final : public PPC64LongBranchThunk {
-public:
- PPC64PILongBranchThunk(Symbol &Dest) : PPC64LongBranchThunk(Dest) {
- assert(!Dest.IsPreemptible);
- if (Dest.isInPPC64Branchlt())
- return;
-
- In.PPC64LongBranchTarget->addEntry(Dest);
- In.RelaDyn->addReloc({Target->RelativeRel, In.PPC64LongBranchTarget,
- Dest.getPPC64LongBranchOffset(), true, &Dest,
- getPPC64GlobalEntryToLocalEntryOffset(Dest.StOther)});
- }
-};
-
-class PPC64PDLongBranchThunk final : public PPC64LongBranchThunk {
-public:
- PPC64PDLongBranchThunk(Symbol &Dest) : PPC64LongBranchThunk(Dest) {
- if (!Dest.isInPPC64Branchlt())
- In.PPC64LongBranchTarget->addEntry(Dest);
- }
-};
-
-} // end anonymous namespace
-
-Defined *Thunk::addSymbol(StringRef Name, uint8_t Type, uint64_t Value,
- InputSectionBase &Section) {
- Defined *D = addSyntheticLocal(Name, Type, Value, /*Size=*/0, Section);
- Syms.push_back(D);
- return D;
-}
-
-void Thunk::setOffset(uint64_t NewOffset) {
- for (Defined *D : Syms)
- D->Value = D->Value - Offset + NewOffset;
- Offset = NewOffset;
-}
-
-// AArch64 long range Thunks
-
-static uint64_t getAArch64ThunkDestVA(const Symbol &S) {
- uint64_t V = S.isInPlt() ? S.getPltVA() : S.getVA();
- return V;
-}
-
-void AArch64ABSLongThunk::writeTo(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0x50, 0x00, 0x00, 0x58, // ldr x16, L0
- 0x00, 0x02, 0x1f, 0xd6, // br x16
- 0x00, 0x00, 0x00, 0x00, // L0: .xword S
- 0x00, 0x00, 0x00, 0x00,
- };
- uint64_t S = getAArch64ThunkDestVA(Destination);
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf + 8, R_AARCH64_ABS64, S);
-}
-
-void AArch64ABSLongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__AArch64AbsLongThunk_" + Destination.getName()),
- STT_FUNC, 0, IS);
- addSymbol("$x", STT_NOTYPE, 0, IS);
- addSymbol("$d", STT_NOTYPE, 8, IS);
-}
-
-// This Thunk has a maximum range of 4Gb, this is sufficient for all programs
-// using the small code model, including pc-relative ones. At time of writing
-// clang and gcc do not support the large code model for position independent
-// code so it is safe to use this for position independent thunks without
-// worrying about the destination being more than 4Gb away.
-void AArch64ADRPThunk::writeTo(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0x10, 0x00, 0x00, 0x90, // adrp x16, Dest R_AARCH64_ADR_PREL_PG_HI21(Dest)
- 0x10, 0x02, 0x00, 0x91, // add x16, x16, R_AARCH64_ADD_ABS_LO12_NC(Dest)
- 0x00, 0x02, 0x1f, 0xd6, // br x16
- };
- uint64_t S = getAArch64ThunkDestVA(Destination);
- uint64_t P = getThunkTargetSym()->getVA();
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf, R_AARCH64_ADR_PREL_PG_HI21,
- getAArch64Page(S) - getAArch64Page(P));
- Target->relocateOne(Buf + 4, R_AARCH64_ADD_ABS_LO12_NC, S);
-}
-
-void AArch64ADRPThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__AArch64ADRPThunk_" + Destination.getName()), STT_FUNC,
- 0, IS);
- addSymbol("$x", STT_NOTYPE, 0, IS);
-}
-
-// ARM Target Thunks
-static uint64_t getARMThunkDestVA(const Symbol &S) {
- uint64_t V = S.isInPlt() ? S.getPltVA() : S.getVA();
- return SignExtend64<32>(V);
-}
-
-// This function returns true if the target is not Thumb and is within 2^26, and
-// it has not previously returned false (see comment for MayUseShortThunk).
-bool ARMThunk::mayUseShortThunk() {
- if (!MayUseShortThunk)
- return false;
- uint64_t S = getARMThunkDestVA(Destination);
- if (S & 1) {
- MayUseShortThunk = false;
- return false;
- }
- uint64_t P = getThunkTargetSym()->getVA();
- int64_t Offset = S - P - 8;
- MayUseShortThunk = llvm::isInt<26>(Offset);
- return MayUseShortThunk;
-}
-
-void ARMThunk::writeTo(uint8_t *Buf) {
- if (!mayUseShortThunk()) {
- writeLong(Buf);
- return;
- }
-
- uint64_t S = getARMThunkDestVA(Destination);
- uint64_t P = getThunkTargetSym()->getVA();
- int64_t Offset = S - P - 8;
- const uint8_t Data[] = {
- 0x00, 0x00, 0x00, 0xea, // b S
- };
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf, R_ARM_JUMP24, Offset);
-}
-
-bool ARMThunk::isCompatibleWith(RelType Type) const {
- // Thumb branch relocations can't use BLX
- return Type != R_ARM_THM_JUMP19 && Type != R_ARM_THM_JUMP24;
-}
-
-// This function returns true if the target is Thumb and is within 2^25, and
-// it has not previously returned false (see comment for MayUseShortThunk).
-bool ThumbThunk::mayUseShortThunk() {
- if (!MayUseShortThunk)
- return false;
- uint64_t S = getARMThunkDestVA(Destination);
- if ((S & 1) == 0) {
- MayUseShortThunk = false;
- return false;
- }
- uint64_t P = getThunkTargetSym()->getVA() & ~1;
- int64_t Offset = S - P - 4;
- MayUseShortThunk = llvm::isInt<25>(Offset);
- return MayUseShortThunk;
-}
-
-void ThumbThunk::writeTo(uint8_t *Buf) {
- if (!mayUseShortThunk()) {
- writeLong(Buf);
- return;
- }
-
- uint64_t S = getARMThunkDestVA(Destination);
- uint64_t P = getThunkTargetSym()->getVA();
- int64_t Offset = S - P - 4;
- const uint8_t Data[] = {
- 0x00, 0xf0, 0x00, 0xb0, // b.w S
- };
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf, R_ARM_THM_JUMP24, Offset);
-}
-
-bool ThumbThunk::isCompatibleWith(RelType Type) const {
- // ARM branch relocations can't use BLX
- return Type != R_ARM_JUMP24 && Type != R_ARM_PC24 && Type != R_ARM_PLT32;
-}
-
-void ARMV7ABSLongThunk::writeLong(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0x00, 0xc0, 0x00, 0xe3, // movw ip,:lower16:S
- 0x00, 0xc0, 0x40, 0xe3, // movt ip,:upper16:S
- 0x1c, 0xff, 0x2f, 0xe1, // bx ip
- };
- uint64_t S = getARMThunkDestVA(Destination);
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf, R_ARM_MOVW_ABS_NC, S);
- Target->relocateOne(Buf + 4, R_ARM_MOVT_ABS, S);
-}
-
-void ARMV7ABSLongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__ARMv7ABSLongThunk_" + Destination.getName()),
- STT_FUNC, 0, IS);
- addSymbol("$a", STT_NOTYPE, 0, IS);
-}
-
-void ThumbV7ABSLongThunk::writeLong(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0x40, 0xf2, 0x00, 0x0c, // movw ip, :lower16:S
- 0xc0, 0xf2, 0x00, 0x0c, // movt ip, :upper16:S
- 0x60, 0x47, // bx ip
- };
- uint64_t S = getARMThunkDestVA(Destination);
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf, R_ARM_THM_MOVW_ABS_NC, S);
- Target->relocateOne(Buf + 4, R_ARM_THM_MOVT_ABS, S);
-}
-
-void ThumbV7ABSLongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__Thumbv7ABSLongThunk_" + Destination.getName()),
- STT_FUNC, 1, IS);
- addSymbol("$t", STT_NOTYPE, 0, IS);
-}
-
-void ARMV7PILongThunk::writeLong(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0xf0, 0xcf, 0x0f, 0xe3, // P: movw ip,:lower16:S - (P + (L1-P) + 8)
- 0x00, 0xc0, 0x40, 0xe3, // movt ip,:upper16:S - (P + (L1-P) + 8)
- 0x0f, 0xc0, 0x8c, 0xe0, // L1: add ip, ip, pc
- 0x1c, 0xff, 0x2f, 0xe1, // bx ip
- };
- uint64_t S = getARMThunkDestVA(Destination);
- uint64_t P = getThunkTargetSym()->getVA();
- int64_t Offset = S - P - 16;
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf, R_ARM_MOVW_PREL_NC, Offset);
- Target->relocateOne(Buf + 4, R_ARM_MOVT_PREL, Offset);
-}
-
-void ARMV7PILongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__ARMV7PILongThunk_" + Destination.getName()), STT_FUNC,
- 0, IS);
- addSymbol("$a", STT_NOTYPE, 0, IS);
-}
-
-void ThumbV7PILongThunk::writeLong(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0x4f, 0xf6, 0xf4, 0x7c, // P: movw ip,:lower16:S - (P + (L1-P) + 4)
- 0xc0, 0xf2, 0x00, 0x0c, // movt ip,:upper16:S - (P + (L1-P) + 4)
- 0xfc, 0x44, // L1: add ip, pc
- 0x60, 0x47, // bx ip
- };
- uint64_t S = getARMThunkDestVA(Destination);
- uint64_t P = getThunkTargetSym()->getVA() & ~0x1;
- int64_t Offset = S - P - 12;
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf, R_ARM_THM_MOVW_PREL_NC, Offset);
- Target->relocateOne(Buf + 4, R_ARM_THM_MOVT_PREL, Offset);
-}
-
-void ThumbV7PILongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__ThumbV7PILongThunk_" + Destination.getName()),
- STT_FUNC, 1, IS);
- addSymbol("$t", STT_NOTYPE, 0, IS);
-}
-
-void ARMV5ABSLongThunk::writeLong(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0x04, 0xf0, 0x1f, 0xe5, // ldr pc, [pc,#-4] ; L1
- 0x00, 0x00, 0x00, 0x00, // L1: .word S
- };
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf + 4, R_ARM_ABS32, getARMThunkDestVA(Destination));
-}
-
-void ARMV5ABSLongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__ARMv5ABSLongThunk_" + Destination.getName()),
- STT_FUNC, 0, IS);
- addSymbol("$a", STT_NOTYPE, 0, IS);
- addSymbol("$d", STT_NOTYPE, 4, IS);
-}
-
-bool ARMV5ABSLongThunk::isCompatibleWith(uint32_t RelocType) const {
- // Thumb branch relocations can't use BLX
- return RelocType != R_ARM_THM_JUMP19 && RelocType != R_ARM_THM_JUMP24;
-}
-
-void ARMV5PILongThunk::writeLong(uint8_t *Buf) {
- const uint8_t Data[] = {
- 0x04, 0xc0, 0x9f, 0xe5, // P: ldr ip, [pc,#4] ; L2
- 0x0c, 0xc0, 0x8f, 0xe0, // L1: add ip, pc, ip
- 0x1c, 0xff, 0x2f, 0xe1, // bx ip
- 0x00, 0x00, 0x00, 0x00, // L2: .word S - (P + (L1 - P) + 8)
- };
- uint64_t S = getARMThunkDestVA(Destination);
- uint64_t P = getThunkTargetSym()->getVA() & ~0x1;
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf + 12, R_ARM_REL32, S - P - 12);
-}
-
-void ARMV5PILongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__ARMV5PILongThunk_" + Destination.getName()), STT_FUNC,
- 0, IS);
- addSymbol("$a", STT_NOTYPE, 0, IS);
- addSymbol("$d", STT_NOTYPE, 12, IS);
-}
-
-bool ARMV5PILongThunk::isCompatibleWith(uint32_t RelocType) const {
- // Thumb branch relocations can't use BLX
- return RelocType != R_ARM_THM_JUMP19 && RelocType != R_ARM_THM_JUMP24;
-}
-
-void ThumbV6MABSLongThunk::writeLong(uint8_t *Buf) {
- // Most Thumb instructions cannot access the high registers r8 - r15. As the
- // only register we can corrupt is r12 we must instead spill a low register
- // to the stack to use as a scratch register. We push r1 even though we
- // don't need to get some space to use for the return address.
- const uint8_t Data[] = {
- 0x03, 0xb4, // push {r0, r1} ; Obtain scratch registers
- 0x01, 0x48, // ldr r0, [pc, #4] ; L1
- 0x01, 0x90, // str r0, [sp, #4] ; SP + 4 = S
- 0x01, 0xbd, // pop {r0, pc} ; restore r0 and branch to dest
- 0x00, 0x00, 0x00, 0x00 // L1: .word S
- };
- uint64_t S = getARMThunkDestVA(Destination);
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf + 8, R_ARM_ABS32, S);
-}
-
-void ThumbV6MABSLongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__Thumbv6MABSLongThunk_" + Destination.getName()),
- STT_FUNC, 1, IS);
- addSymbol("$t", STT_NOTYPE, 0, IS);
- addSymbol("$d", STT_NOTYPE, 8, IS);
-}
-
-void ThumbV6MPILongThunk::writeLong(uint8_t *Buf) {
- // Most Thumb instructions cannot access the high registers r8 - r15. As the
- // only register we can corrupt is ip (r12) we must instead spill a low
- // register to the stack to use as a scratch register.
- const uint8_t Data[] = {
- 0x01, 0xb4, // P: push {r0} ; Obtain scratch register
- 0x02, 0x48, // ldr r0, [pc, #8] ; L2
- 0x84, 0x46, // mov ip, r0 ; high to low register
- 0x01, 0xbc, // pop {r0} ; restore scratch register
- 0xe7, 0x44, // L1: add pc, ip ; transfer control
- 0xc0, 0x46, // nop ; pad to 4-byte boundary
- 0x00, 0x00, 0x00, 0x00, // L2: .word S - (P + (L1 - P) + 4)
- };
- uint64_t S = getARMThunkDestVA(Destination);
- uint64_t P = getThunkTargetSym()->getVA() & ~0x1;
- memcpy(Buf, Data, sizeof(Data));
- Target->relocateOne(Buf + 12, R_ARM_REL32, S - P - 12);
-}
-
-void ThumbV6MPILongThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__Thumbv6MPILongThunk_" + Destination.getName()),
- STT_FUNC, 1, IS);
- addSymbol("$t", STT_NOTYPE, 0, IS);
- addSymbol("$d", STT_NOTYPE, 12, IS);
-}
-
-// Write MIPS LA25 thunk code to call PIC function from the non-PIC one.
-void MipsThunk::writeTo(uint8_t *Buf) {
- uint64_t S = Destination.getVA();
- write32(Buf, 0x3c190000); // lui $25, %hi(func)
- write32(Buf + 4, 0x08000000 | (S >> 2)); // j func
- write32(Buf + 8, 0x27390000); // addiu $25, $25, %lo(func)
- write32(Buf + 12, 0x00000000); // nop
- Target->relocateOne(Buf, R_MIPS_HI16, S);
- Target->relocateOne(Buf + 8, R_MIPS_LO16, S);
-}
-
-void MipsThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__LA25Thunk_" + Destination.getName()), STT_FUNC, 0,
- IS);
-}
-
-InputSection *MipsThunk::getTargetInputSection() const {
- auto &DR = cast<Defined>(Destination);
- return dyn_cast<InputSection>(DR.Section);
-}
-
-// Write microMIPS R2-R5 LA25 thunk code
-// to call PIC function from the non-PIC one.
-void MicroMipsThunk::writeTo(uint8_t *Buf) {
- uint64_t S = Destination.getVA() | 1;
- write16(Buf, 0x41b9); // lui $25, %hi(func)
- write16(Buf + 4, 0xd400); // j func
- write16(Buf + 8, 0x3339); // addiu $25, $25, %lo(func)
- write16(Buf + 12, 0x0c00); // nop
- Target->relocateOne(Buf, R_MICROMIPS_HI16, S);
- Target->relocateOne(Buf + 4, R_MICROMIPS_26_S1, S);
- Target->relocateOne(Buf + 8, R_MICROMIPS_LO16, S);
-}
-
-void MicroMipsThunk::addSymbols(ThunkSection &IS) {
- Defined *D = addSymbol(
- Saver.save("__microLA25Thunk_" + Destination.getName()), STT_FUNC, 0, IS);
- D->StOther |= STO_MIPS_MICROMIPS;
-}
-
-InputSection *MicroMipsThunk::getTargetInputSection() const {
- auto &DR = cast<Defined>(Destination);
- return dyn_cast<InputSection>(DR.Section);
-}
-
-// Write microMIPS R6 LA25 thunk code
-// to call PIC function from the non-PIC one.
-void MicroMipsR6Thunk::writeTo(uint8_t *Buf) {
- uint64_t S = Destination.getVA() | 1;
- uint64_t P = getThunkTargetSym()->getVA();
- write16(Buf, 0x1320); // lui $25, %hi(func)
- write16(Buf + 4, 0x3339); // addiu $25, $25, %lo(func)
- write16(Buf + 8, 0x9400); // bc func
- Target->relocateOne(Buf, R_MICROMIPS_HI16, S);
- Target->relocateOne(Buf + 4, R_MICROMIPS_LO16, S);
- Target->relocateOne(Buf + 8, R_MICROMIPS_PC26_S1, S - P - 12);
-}
-
-void MicroMipsR6Thunk::addSymbols(ThunkSection &IS) {
- Defined *D = addSymbol(
- Saver.save("__microLA25Thunk_" + Destination.getName()), STT_FUNC, 0, IS);
- D->StOther |= STO_MIPS_MICROMIPS;
-}
-
-InputSection *MicroMipsR6Thunk::getTargetInputSection() const {
- auto &DR = cast<Defined>(Destination);
- return dyn_cast<InputSection>(DR.Section);
-}
-
-static void writePPCLoadAndBranch(uint8_t *Buf, int64_t Offset) {
- uint16_t OffHa = (Offset + 0x8000) >> 16;
- uint16_t OffLo = Offset & 0xffff;
-
- write32(Buf + 0, 0x3d820000 | OffHa); // addis r12, r2, OffHa
- write32(Buf + 4, 0xe98c0000 | OffLo); // ld r12, OffLo(r12)
- write32(Buf + 8, 0x7d8903a6); // mtctr r12
- write32(Buf + 12, 0x4e800420); // bctr
-}
-
-void PPC64PltCallStub::writeTo(uint8_t *Buf) {
- int64_t Offset = Destination.getGotPltVA() - getPPC64TocBase();
- // Save the TOC pointer to the save-slot reserved in the call frame.
- write32(Buf + 0, 0xf8410018); // std r2,24(r1)
- writePPCLoadAndBranch(Buf + 4, Offset);
-}
-
-void PPC64PltCallStub::addSymbols(ThunkSection &IS) {
- Defined *S = addSymbol(Saver.save("__plt_" + Destination.getName()), STT_FUNC,
- 0, IS);
- S->NeedsTocRestore = true;
-}
-
-void PPC64LongBranchThunk::writeTo(uint8_t *Buf) {
- int64_t Offset = Destination.getPPC64LongBranchTableVA() - getPPC64TocBase();
- writePPCLoadAndBranch(Buf, Offset);
-}
-
-void PPC64LongBranchThunk::addSymbols(ThunkSection &IS) {
- addSymbol(Saver.save("__long_branch_" + Destination.getName()), STT_FUNC, 0,
- IS);
-}
-
-Thunk::Thunk(Symbol &D) : Destination(D), Offset(0) {}
-
-Thunk::~Thunk() = default;
-
-static Thunk *addThunkAArch64(RelType Type, Symbol &S) {
- if (Type != R_AARCH64_CALL26 && Type != R_AARCH64_JUMP26)
- fatal("unrecognized relocation type");
- if (Config->PicThunk)
- return make<AArch64ADRPThunk>(S);
- return make<AArch64ABSLongThunk>(S);
-}
-
-// Creates a thunk for Thumb-ARM interworking.
-// Arm Architectures v5 and v6 do not support Thumb2 technology. This means
-// - MOVT and MOVW instructions cannot be used
-// - Only Thumb relocation that can generate a Thunk is a BL, this can always
-// be transformed into a BLX
-static Thunk *addThunkPreArmv7(RelType Reloc, Symbol &S) {
- switch (Reloc) {
- case R_ARM_PC24:
- case R_ARM_PLT32:
- case R_ARM_JUMP24:
- case R_ARM_CALL:
- case R_ARM_THM_CALL:
- if (Config->PicThunk)
- return make<ARMV5PILongThunk>(S);
- return make<ARMV5ABSLongThunk>(S);
- }
- fatal("relocation " + toString(Reloc) + " to " + toString(S) +
- " not supported for Armv5 or Armv6 targets");
-}
-
-// Create a thunk for Thumb long branch on V6-M.
-// Arm Architecture v6-M only supports Thumb instructions. This means
-// - MOVT and MOVW instructions cannot be used.
-// - Only a limited number of instructions can access registers r8 and above
-// - No interworking support is needed (all Thumb).
-static Thunk *addThunkV6M(RelType Reloc, Symbol &S) {
- switch (Reloc) {
- case R_ARM_THM_JUMP19:
- case R_ARM_THM_JUMP24:
- case R_ARM_THM_CALL:
- if (Config->Pic)
- return make<ThumbV6MPILongThunk>(S);
- return make<ThumbV6MABSLongThunk>(S);
- }
- fatal("relocation " + toString(Reloc) + " to " + toString(S) +
- " not supported for Armv6-M targets");
-}
-
-// Creates a thunk for Thumb-ARM interworking or branch range extension.
-static Thunk *addThunkArm(RelType Reloc, Symbol &S) {
- // Decide which Thunk is needed based on:
- // Available instruction set
- // - An Arm Thunk can only be used if Arm state is available.
- // - A Thumb Thunk can only be used if Thumb state is available.
- // - Can only use a Thunk if it uses instructions that the Target supports.
- // Relocation is branch or branch and link
- // - Branch instructions cannot change state, can only select Thunk that
- // starts in the same state as the caller.
- // - Branch and link relocations can change state, can select Thunks from
- // either Arm or Thumb.
- // Position independent Thunks if we require position independent code.
-
- // Handle architectures that have restrictions on the instructions that they
- // can use in Thunks. The flags below are set by reading the BuildAttributes
- // of the input objects. InputFiles.cpp contains the mapping from ARM
- // architecture to flag.
- if (!Config->ARMHasMovtMovw) {
- if (!Config->ARMJ1J2BranchEncoding)
- return addThunkPreArmv7(Reloc, S);
- return addThunkV6M(Reloc, S);
- }
-
- switch (Reloc) {
- case R_ARM_PC24:
- case R_ARM_PLT32:
- case R_ARM_JUMP24:
- case R_ARM_CALL:
- if (Config->PicThunk)
- return make<ARMV7PILongThunk>(S);
- return make<ARMV7ABSLongThunk>(S);
- case R_ARM_THM_JUMP19:
- case R_ARM_THM_JUMP24:
- case R_ARM_THM_CALL:
- if (Config->PicThunk)
- return make<ThumbV7PILongThunk>(S);
- return make<ThumbV7ABSLongThunk>(S);
- }
- fatal("unrecognized relocation type");
-}
-
-static Thunk *addThunkMips(RelType Type, Symbol &S) {
- if ((S.StOther & STO_MIPS_MICROMIPS) && isMipsR6())
- return make<MicroMipsR6Thunk>(S);
- if (S.StOther & STO_MIPS_MICROMIPS)
- return make<MicroMipsThunk>(S);
- return make<MipsThunk>(S);
-}
-
-static Thunk *addThunkPPC64(RelType Type, Symbol &S) {
- assert(Type == R_PPC64_REL24 && "unexpected relocation type for thunk");
- if (S.isInPlt())
- return make<PPC64PltCallStub>(S);
-
- if (Config->PicThunk)
- return make<PPC64PILongBranchThunk>(S);
-
- return make<PPC64PDLongBranchThunk>(S);
-}
-
-Thunk *addThunk(RelType Type, Symbol &S) {
- if (Config->EMachine == EM_AARCH64)
- return addThunkAArch64(Type, S);
-
- if (Config->EMachine == EM_ARM)
- return addThunkArm(Type, S);
-
- if (Config->EMachine == EM_MIPS)
- return addThunkMips(Type, S);
-
- if (Config->EMachine == EM_PPC64)
- return addThunkPPC64(Type, S);
-
- llvm_unreachable("add Thunk only supported for ARM, Mips and PowerPC");
-}
-
-} // end namespace elf
-} // end namespace lld
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.