Sink ARM mc routines into MCTargetDesc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135825 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 389 insertions, 0 deletions

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 <reloc.h>.
+  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 <reloc.h>.
+  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 <reloc.h>.
+  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);
+}