From be74029f44c32efc09274a16cbff588ad10dc5ea Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Sat, 23 Jul 2011 00:00:19 +0000 Subject: Sink ARM mc routines into MCTargetDesc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135825 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../ARM/MCTargetDesc/ARMMachObjectWriter.cpp | 389 +++++++++++++++++++++ 1 file changed, 389 insertions(+) create mode 100644 lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp (limited to 'lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp') diff --git a/lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp b/lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp new file mode 100644 index 0000000..bc1bf3a --- /dev/null +++ b/lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp @@ -0,0 +1,389 @@ +//===-- ARMMachObjectWriter.cpp - ARM Mach Object Writer ------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "MCTargetDesc/ARMBaseInfo.h" +#include "MCTargetDesc/ARMFixupKinds.h" +#include "llvm/ADT/Twine.h" +#include "llvm/MC/MCAssembler.h" +#include "llvm/MC/MCAsmLayout.h" +#include "llvm/MC/MCMachObjectWriter.h" +#include "llvm/MC/MCExpr.h" +#include "llvm/MC/MCFixup.h" +#include "llvm/MC/MCFixupKindInfo.h" +#include "llvm/MC/MCValue.h" +#include "llvm/Object/MachOFormat.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Target/TargetAsmBackend.h" +using namespace llvm; +using namespace llvm::object; + +namespace { +class ARMMachObjectWriter : public MCMachObjectTargetWriter { + void RecordARMScatteredRelocation(MachObjectWriter *Writer, + const MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCFragment *Fragment, + const MCFixup &Fixup, + MCValue Target, + unsigned Log2Size, + uint64_t &FixedValue); + void RecordARMMovwMovtRelocation(MachObjectWriter *Writer, + const MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCFragment *Fragment, + const MCFixup &Fixup, MCValue Target, + uint64_t &FixedValue); + +public: + ARMMachObjectWriter(bool Is64Bit, uint32_t CPUType, + uint32_t CPUSubtype) + : MCMachObjectTargetWriter(Is64Bit, CPUType, CPUSubtype, + /*UseAggressiveSymbolFolding=*/true) {} + + void RecordRelocation(MachObjectWriter *Writer, + const MCAssembler &Asm, const MCAsmLayout &Layout, + const MCFragment *Fragment, const MCFixup &Fixup, + MCValue Target, uint64_t &FixedValue); +}; +} + +static bool getARMFixupKindMachOInfo(unsigned Kind, unsigned &RelocType, + unsigned &Log2Size) { + RelocType = unsigned(macho::RIT_Vanilla); + Log2Size = ~0U; + + switch (Kind) { + default: + return false; + + case FK_Data_1: + Log2Size = llvm::Log2_32(1); + return true; + case FK_Data_2: + Log2Size = llvm::Log2_32(2); + return true; + case FK_Data_4: + Log2Size = llvm::Log2_32(4); + return true; + case FK_Data_8: + Log2Size = llvm::Log2_32(8); + return true; + + // Handle 24-bit branch kinds. + case ARM::fixup_arm_ldst_pcrel_12: + case ARM::fixup_arm_pcrel_10: + case ARM::fixup_arm_adr_pcrel_12: + case ARM::fixup_arm_condbranch: + case ARM::fixup_arm_uncondbranch: + RelocType = unsigned(macho::RIT_ARM_Branch24Bit); + // Report as 'long', even though that is not quite accurate. + Log2Size = llvm::Log2_32(4); + return true; + + // Handle Thumb branches. + case ARM::fixup_arm_thumb_br: + RelocType = unsigned(macho::RIT_ARM_ThumbBranch22Bit); + Log2Size = llvm::Log2_32(2); + return true; + + case ARM::fixup_t2_uncondbranch: + case ARM::fixup_arm_thumb_bl: + case ARM::fixup_arm_thumb_blx: + RelocType = unsigned(macho::RIT_ARM_ThumbBranch22Bit); + Log2Size = llvm::Log2_32(4); + return true; + + case ARM::fixup_arm_movt_hi16: + case ARM::fixup_arm_movt_hi16_pcrel: + case ARM::fixup_t2_movt_hi16: + case ARM::fixup_t2_movt_hi16_pcrel: + RelocType = unsigned(macho::RIT_ARM_HalfDifference); + // Report as 'long', even though that is not quite accurate. + Log2Size = llvm::Log2_32(4); + return true; + + case ARM::fixup_arm_movw_lo16: + case ARM::fixup_arm_movw_lo16_pcrel: + case ARM::fixup_t2_movw_lo16: + case ARM::fixup_t2_movw_lo16_pcrel: + RelocType = unsigned(macho::RIT_ARM_Half); + // Report as 'long', even though that is not quite accurate. + Log2Size = llvm::Log2_32(4); + return true; + } +} + +void ARMMachObjectWriter:: +RecordARMMovwMovtRelocation(MachObjectWriter *Writer, + const MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCFragment *Fragment, + const MCFixup &Fixup, + MCValue Target, + uint64_t &FixedValue) { + uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset(); + unsigned IsPCRel = Writer->isFixupKindPCRel(Asm, Fixup.getKind()); + unsigned Type = macho::RIT_ARM_Half; + + // See . + const MCSymbol *A = &Target.getSymA()->getSymbol(); + MCSymbolData *A_SD = &Asm.getSymbolData(*A); + + if (!A_SD->getFragment()) + report_fatal_error("symbol '" + A->getName() + + "' can not be undefined in a subtraction expression"); + + uint32_t Value = Writer->getSymbolAddress(A_SD, Layout); + uint32_t Value2 = 0; + uint64_t SecAddr = + Writer->getSectionAddress(A_SD->getFragment()->getParent()); + FixedValue += SecAddr; + + if (const MCSymbolRefExpr *B = Target.getSymB()) { + MCSymbolData *B_SD = &Asm.getSymbolData(B->getSymbol()); + + if (!B_SD->getFragment()) + report_fatal_error("symbol '" + B->getSymbol().getName() + + "' can not be undefined in a subtraction expression"); + + // Select the appropriate difference relocation type. + Type = macho::RIT_ARM_HalfDifference; + Value2 = Writer->getSymbolAddress(B_SD, Layout); + FixedValue -= Writer->getSectionAddress(B_SD->getFragment()->getParent()); + } + + // Relocations are written out in reverse order, so the PAIR comes first. + // ARM_RELOC_HALF and ARM_RELOC_HALF_SECTDIFF abuse the r_length field: + // + // For these two r_type relocations they always have a pair following them and + // the r_length bits are used differently. The encoding of the r_length is as + // follows: + // low bit of r_length: + // 0 - :lower16: for movw instructions + // 1 - :upper16: for movt instructions + // high bit of r_length: + // 0 - arm instructions + // 1 - thumb instructions + // the other half of the relocated expression is in the following pair + // relocation entry in the the low 16 bits of r_address field. + unsigned ThumbBit = 0; + unsigned MovtBit = 0; + switch ((unsigned)Fixup.getKind()) { + default: break; + case ARM::fixup_arm_movt_hi16: + case ARM::fixup_arm_movt_hi16_pcrel: + MovtBit = 1; + break; + case ARM::fixup_t2_movt_hi16: + case ARM::fixup_t2_movt_hi16_pcrel: + MovtBit = 1; + // Fallthrough + case ARM::fixup_t2_movw_lo16: + case ARM::fixup_t2_movw_lo16_pcrel: + ThumbBit = 1; + break; + } + + + if (Type == macho::RIT_ARM_HalfDifference) { + uint32_t OtherHalf = MovtBit + ? (FixedValue & 0xffff) : ((FixedValue & 0xffff0000) >> 16); + + macho::RelocationEntry MRE; + MRE.Word0 = ((OtherHalf << 0) | + (macho::RIT_Pair << 24) | + (MovtBit << 28) | + (ThumbBit << 29) | + (IsPCRel << 30) | + macho::RF_Scattered); + MRE.Word1 = Value2; + Writer->addRelocation(Fragment->getParent(), MRE); + } + + macho::RelocationEntry MRE; + MRE.Word0 = ((FixupOffset << 0) | + (Type << 24) | + (MovtBit << 28) | + (ThumbBit << 29) | + (IsPCRel << 30) | + macho::RF_Scattered); + MRE.Word1 = Value; + Writer->addRelocation(Fragment->getParent(), MRE); +} + +void ARMMachObjectWriter::RecordARMScatteredRelocation(MachObjectWriter *Writer, + const MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCFragment *Fragment, + const MCFixup &Fixup, + MCValue Target, + unsigned Log2Size, + uint64_t &FixedValue) { + uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset(); + unsigned IsPCRel = Writer->isFixupKindPCRel(Asm, Fixup.getKind()); + unsigned Type = macho::RIT_Vanilla; + + // See . + const MCSymbol *A = &Target.getSymA()->getSymbol(); + MCSymbolData *A_SD = &Asm.getSymbolData(*A); + + if (!A_SD->getFragment()) + report_fatal_error("symbol '" + A->getName() + + "' can not be undefined in a subtraction expression"); + + uint32_t Value = Writer->getSymbolAddress(A_SD, Layout); + uint64_t SecAddr = Writer->getSectionAddress(A_SD->getFragment()->getParent()); + FixedValue += SecAddr; + uint32_t Value2 = 0; + + if (const MCSymbolRefExpr *B = Target.getSymB()) { + MCSymbolData *B_SD = &Asm.getSymbolData(B->getSymbol()); + + if (!B_SD->getFragment()) + report_fatal_error("symbol '" + B->getSymbol().getName() + + "' can not be undefined in a subtraction expression"); + + // Select the appropriate difference relocation type. + Type = macho::RIT_Difference; + Value2 = Writer->getSymbolAddress(B_SD, Layout); + FixedValue -= Writer->getSectionAddress(B_SD->getFragment()->getParent()); + } + + // Relocations are written out in reverse order, so the PAIR comes first. + if (Type == macho::RIT_Difference || + Type == macho::RIT_Generic_LocalDifference) { + macho::RelocationEntry MRE; + MRE.Word0 = ((0 << 0) | + (macho::RIT_Pair << 24) | + (Log2Size << 28) | + (IsPCRel << 30) | + macho::RF_Scattered); + MRE.Word1 = Value2; + Writer->addRelocation(Fragment->getParent(), MRE); + } + + macho::RelocationEntry MRE; + MRE.Word0 = ((FixupOffset << 0) | + (Type << 24) | + (Log2Size << 28) | + (IsPCRel << 30) | + macho::RF_Scattered); + MRE.Word1 = Value; + Writer->addRelocation(Fragment->getParent(), MRE); +} + +void ARMMachObjectWriter::RecordRelocation(MachObjectWriter *Writer, + const MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCFragment *Fragment, + const MCFixup &Fixup, + MCValue Target, + uint64_t &FixedValue) { + unsigned IsPCRel = Writer->isFixupKindPCRel(Asm, Fixup.getKind()); + unsigned Log2Size; + unsigned RelocType = macho::RIT_Vanilla; + if (!getARMFixupKindMachOInfo(Fixup.getKind(), RelocType, Log2Size)) { + report_fatal_error("unknown ARM fixup kind!"); + return; + } + + // If this is a difference or a defined symbol plus an offset, then we need a + // scattered relocation entry. Differences always require scattered + // relocations. + if (Target.getSymB()) { + if (RelocType == macho::RIT_ARM_Half || + RelocType == macho::RIT_ARM_HalfDifference) + return RecordARMMovwMovtRelocation(Writer, Asm, Layout, Fragment, Fixup, + Target, FixedValue); + return RecordARMScatteredRelocation(Writer, Asm, Layout, Fragment, Fixup, + Target, Log2Size, FixedValue); + } + + // Get the symbol data, if any. + MCSymbolData *SD = 0; + if (Target.getSymA()) + SD = &Asm.getSymbolData(Target.getSymA()->getSymbol()); + + // FIXME: For other platforms, we need to use scattered relocations for + // internal relocations with offsets. If this is an internal relocation with + // an offset, it also needs a scattered relocation entry. + // + // Is this right for ARM? + uint32_t Offset = Target.getConstant(); + if (IsPCRel && RelocType == macho::RIT_Vanilla) + Offset += 1 << Log2Size; + if (Offset && SD && !Writer->doesSymbolRequireExternRelocation(SD)) + return RecordARMScatteredRelocation(Writer, Asm, Layout, Fragment, Fixup, + Target, Log2Size, FixedValue); + + // See . + uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset(); + unsigned Index = 0; + unsigned IsExtern = 0; + unsigned Type = 0; + + if (Target.isAbsolute()) { // constant + // FIXME! + report_fatal_error("FIXME: relocations to absolute targets " + "not yet implemented"); + } else { + // Resolve constant variables. + if (SD->getSymbol().isVariable()) { + int64_t Res; + if (SD->getSymbol().getVariableValue()->EvaluateAsAbsolute( + Res, Layout, Writer->getSectionAddressMap())) { + FixedValue = Res; + return; + } + } + + // Check whether we need an external or internal relocation. + if (Writer->doesSymbolRequireExternRelocation(SD)) { + IsExtern = 1; + Index = SD->getIndex(); + + // For external relocations, make sure to offset the fixup value to + // compensate for the addend of the symbol address, if it was + // undefined. This occurs with weak definitions, for example. + if (!SD->Symbol->isUndefined()) + FixedValue -= Layout.getSymbolOffset(SD); + } else { + // The index is the section ordinal (1-based). + const MCSectionData &SymSD = Asm.getSectionData( + SD->getSymbol().getSection()); + Index = SymSD.getOrdinal() + 1; + FixedValue += Writer->getSectionAddress(&SymSD); + } + if (IsPCRel) + FixedValue -= Writer->getSectionAddress(Fragment->getParent()); + + // The type is determined by the fixup kind. + Type = RelocType; + } + + // struct relocation_info (8 bytes) + macho::RelocationEntry MRE; + MRE.Word0 = FixupOffset; + MRE.Word1 = ((Index << 0) | + (IsPCRel << 24) | + (Log2Size << 25) | + (IsExtern << 27) | + (Type << 28)); + Writer->addRelocation(Fragment->getParent(), MRE); +} + +MCObjectWriter *llvm::createARMMachObjectWriter(raw_ostream &OS, + bool Is64Bit, + uint32_t CPUType, + uint32_t CPUSubtype) { + return createMachObjectWriter(new ARMMachObjectWriter(Is64Bit, + CPUType, + CPUSubtype), + OS, /*IsLittleEndian=*/true); +} -- cgit v1.1