[MCJIT] Significantly refactor the RuntimeDyldMachO class.

The previous implementation of RuntimeDyldMachO mixed logic for all targets
within a single class, creating problems for readability, maintainability, and
performance. To address these issues, this patch strips the RuntimeDyldMachO
class down to just target-independent functionality, and moves all
target-specific functionality into target-specific subclasses RuntimeDyldMachO.

The new class hierarchy is as follows:

class RuntimeDyldMachO
Implemented in RuntimeDyldMachO.{h,cpp}
Contains logic that is completely independent of the target. This consists
mostly of MachO helper utilities which the derived classes use to get their
work done.


template <typename Impl>
class RuntimeDyldMachOCRTPBase<Impl> : public RuntimeDyldMachO
Implemented in RuntimeDyldMachO.h
Contains generic MachO algorithms/data structures that defer to the Impl class
for target-specific behaviors.

RuntimeDyldMachOARM : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOARM>
RuntimeDyldMachOARM64 : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOARM64>
RuntimeDyldMachOI386 : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOI386>
RuntimeDyldMachOX86_64 : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOX86_64>
Implemented in their respective *.h files in lib/ExecutionEngine/RuntimeDyld/MachOTargets
Each of these contains the relocation logic specific to their target architecture.

llvm-svn: 213293

1 files changed, 315 insertions, 0 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOI386.h b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOI386.h
new file mode 100644
index 00000000000..856c6ca3035
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOI386.h
@@ -0,0 +1,315 @@
+//===---- RuntimeDyldMachOI386.h ---- MachO/I386 specific code. ---*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_RUNTIMEDYLDMACHOI386_H
+#define LLVM_RUNTIMEDYLDMACHOI386_H
+
+#include "../RuntimeDyldMachO.h"
+
+#define DEBUG_TYPE "dyld"
+
+namespace llvm {
+
+class RuntimeDyldMachOI386
+    : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOI386> {
+public:
+  RuntimeDyldMachOI386(RTDyldMemoryManager *MM)
+      : RuntimeDyldMachOCRTPBase(MM) {}
+
+  unsigned getMaxStubSize() override { return 0; }
+
+  unsigned getStubAlignment() override { return 1; }
+
+  relocation_iterator
+  processRelocationRef(unsigned SectionID, relocation_iterator RelI,
+                       ObjectImage &ObjImg, ObjSectionToIDMap &ObjSectionToID,
+                       const SymbolTableMap &Symbols, StubMap &Stubs) override {
+    const MachOObjectFile &Obj =
+        static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
+    MachO::any_relocation_info RelInfo =
+        Obj.getRelocation(RelI->getRawDataRefImpl());
+    uint32_t RelType = Obj.getAnyRelocationType(RelInfo);
+
+    if (Obj.isRelocationScattered(RelInfo)) {
+      if (RelType == MachO::GENERIC_RELOC_SECTDIFF ||
+          RelType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF)
+        return processSECTDIFFRelocation(SectionID, RelI, ObjImg,
+                                         ObjSectionToID);
+      else if (Arch == Triple::x86 && RelType == MachO::GENERIC_RELOC_VANILLA)
+        return processI386ScatteredVANILLA(SectionID, RelI, ObjImg,
+                                           ObjSectionToID);
+      llvm_unreachable("Unhandled scattered relocation.");
+    }
+
+    RelocationEntry RE(getBasicRelocationEntry(SectionID, ObjImg, RelI));
+    RelocationValueRef Value(
+        getRelocationValueRef(ObjImg, RelI, RE, ObjSectionToID, Symbols));
+
+    // Addends for external, PC-rel relocations on i386 point back to the zero
+    // offset. Calculate the final offset from the relocation target instead.
+    // This allows us to use the same logic for both external and internal
+    // relocations in resolveI386RelocationRef.
+    // bool IsExtern = Obj.getPlainRelocationExternal(RelInfo);
+    // if (IsExtern && RE.IsPCRel) {
+    //   uint64_t RelocAddr = 0;
+    //   RelI->getAddress(RelocAddr);
+    //   Value.Addend += RelocAddr + 4;
+    // }
+    if (RE.IsPCRel)
+      makeValueAddendPCRel(Value, ObjImg, RelI);
+
+    RE.Addend = Value.Addend;
+
+    if (Value.SymbolName)
+      addRelocationForSymbol(RE, Value.SymbolName);
+    else
+      addRelocationForSection(RE, Value.SectionID);
+
+    return ++RelI;
+  }
+
+  void resolveRelocation(const RelocationEntry &RE, uint64_t Value) {
+    DEBUG(dumpRelocationToResolve(RE, Value));
+
+    const SectionEntry &Section = Sections[RE.SectionID];
+    uint8_t *LocalAddress = Section.Address + RE.Offset;
+
+    if (RE.IsPCRel) {
+      uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
+      Value -= FinalAddress + 4; // see MachOX86_64::resolveRelocation.
+    }
+
+    switch (RE.RelType) {
+    default:
+      llvm_unreachable("Invalid relocation type!");
+    case MachO::GENERIC_RELOC_VANILLA:
+      writeBytesUnaligned(LocalAddress, Value + RE.Addend, 1 << RE.Size);
+      break;
+    case MachO::GENERIC_RELOC_SECTDIFF:
+    case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
+      uint64_t SectionABase = Sections[RE.Sections.SectionA].LoadAddress;
+      uint64_t SectionBBase = Sections[RE.Sections.SectionB].LoadAddress;
+      assert((Value == SectionABase || Value == SectionBBase) &&
+             "Unexpected SECTDIFF relocation value.");
+      Value = SectionABase - SectionBBase + RE.Addend;
+      writeBytesUnaligned(LocalAddress, Value, 1 << RE.Size);
+      break;
+    }
+    case MachO::GENERIC_RELOC_PB_LA_PTR:
+      Error("Relocation type not implemented yet!");
+    }
+  }
+
+  void finalizeSection(ObjectImage &ObjImg, unsigned SectionID,
+                       const SectionRef &Section) {
+    StringRef Name;
+    Section.getName(Name);
+
+    if (Name == "__jump_table")
+      populateJumpTable(cast<MachOObjectFile>(*ObjImg.getObjectFile()), Section,
+                        SectionID);
+    else if (Name == "__pointers")
+      populatePointersSection(cast<MachOObjectFile>(*ObjImg.getObjectFile()),
+                              Section, SectionID);
+  }
+
+private:
+  relocation_iterator
+  processSECTDIFFRelocation(unsigned SectionID, relocation_iterator RelI,
+                            ObjectImage &Obj,
+                            ObjSectionToIDMap &ObjSectionToID) {
+    const MachOObjectFile *MachO =
+        static_cast<const MachOObjectFile *>(Obj.getObjectFile());
+    MachO::any_relocation_info RE =
+        MachO->getRelocation(RelI->getRawDataRefImpl());
+
+    SectionEntry &Section = Sections[SectionID];
+    uint32_t RelocType = MachO->getAnyRelocationType(RE);
+    bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
+    unsigned Size = MachO->getAnyRelocationLength(RE);
+    uint64_t Offset;
+    RelI->getOffset(Offset);
+    uint8_t *LocalAddress = Section.Address + Offset;
+    unsigned NumBytes = 1 << Size;
+    int64_t Addend = 0;
+    memcpy(&Addend, LocalAddress, NumBytes);
+
+    ++RelI;
+    MachO::any_relocation_info RE2 =
+        MachO->getRelocation(RelI->getRawDataRefImpl());
+
+    uint32_t AddrA = MachO->getScatteredRelocationValue(RE);
+    section_iterator SAI = getSectionByAddress(*MachO, AddrA);
+    assert(SAI != MachO->section_end() && "Can't find section for address A");
+    uint64_t SectionABase;
+    SAI->getAddress(SectionABase);
+    uint64_t SectionAOffset = AddrA - SectionABase;
+    SectionRef SectionA = *SAI;
+    bool IsCode;
+    SectionA.isText(IsCode);
+    uint32_t SectionAID =
+        findOrEmitSection(Obj, SectionA, IsCode, ObjSectionToID);
+
+    uint32_t AddrB = MachO->getScatteredRelocationValue(RE2);
+    section_iterator SBI = getSectionByAddress(*MachO, AddrB);
+    assert(SBI != MachO->section_end() && "Can't find section for address B");
+    uint64_t SectionBBase;
+    SBI->getAddress(SectionBBase);
+    uint64_t SectionBOffset = AddrB - SectionBBase;
+    SectionRef SectionB = *SBI;
+    uint32_t SectionBID =
+        findOrEmitSection(Obj, SectionB, IsCode, ObjSectionToID);
+
+    if (Addend != AddrA - AddrB)
+      Error("Unexpected SECTDIFF relocation addend.");
+
+    DEBUG(dbgs() << "Found SECTDIFF: AddrA: " << AddrA << ", AddrB: " << AddrB
+                 << ", Addend: " << Addend << ", SectionA ID: " << SectionAID
+                 << ", SectionAOffset: " << SectionAOffset
+                 << ", SectionB ID: " << SectionBID
+                 << ", SectionBOffset: " << SectionBOffset << "\n");
+    RelocationEntry R(SectionID, Offset, RelocType, 0, SectionAID,
+                      SectionAOffset, SectionBID, SectionBOffset, IsPCRel,
+                      Size);
+
+    addRelocationForSection(R, SectionAID);
+    addRelocationForSection(R, SectionBID);
+
+    return ++RelI;
+  }
+
+  relocation_iterator processI386ScatteredVANILLA(
+      unsigned SectionID, relocation_iterator RelI, ObjectImage &Obj,
+      RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID) {
+    const MachOObjectFile *MachO =
+        static_cast<const MachOObjectFile *>(Obj.getObjectFile());
+    MachO::any_relocation_info RE =
+        MachO->getRelocation(RelI->getRawDataRefImpl());
+
+    SectionEntry &Section = Sections[SectionID];
+    uint32_t RelocType = MachO->getAnyRelocationType(RE);
+    bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
+    unsigned Size = MachO->getAnyRelocationLength(RE);
+    uint64_t Offset;
+    RelI->getOffset(Offset);
+    uint8_t *LocalAddress = Section.Address + Offset;
+    unsigned NumBytes = 1 << Size;
+    int64_t Addend = 0;
+    memcpy(&Addend, LocalAddress, NumBytes);
+
+    unsigned SymbolBaseAddr = MachO->getScatteredRelocationValue(RE);
+    section_iterator TargetSI = getSectionByAddress(*MachO, SymbolBaseAddr);
+    assert(TargetSI != MachO->section_end() && "Can't find section for symbol");
+    uint64_t SectionBaseAddr;
+    TargetSI->getAddress(SectionBaseAddr);
+    SectionRef TargetSection = *TargetSI;
+    bool IsCode;
+    TargetSection.isText(IsCode);
+    uint32_t TargetSectionID =
+        findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID);
+
+    Addend -= SectionBaseAddr;
+    RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
+
+    addRelocationForSection(R, TargetSectionID);
+
+    return ++RelI;
+  }
+
+  // Populate stubs in __jump_table section.
+  void populateJumpTable(MachOObjectFile &Obj, const SectionRef &JTSection,
+                         unsigned JTSectionID) {
+    assert(!Obj.is64Bit() &&
+           "__jump_table section not supported in 64-bit MachO.");
+
+    MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
+    MachO::section Sec32 = Obj.getSection(JTSection.getRawDataRefImpl());
+    uint32_t JTSectionSize = Sec32.size;
+    unsigned FirstIndirectSymbol = Sec32.reserved1;
+    unsigned JTEntrySize = Sec32.reserved2;
+    unsigned NumJTEntries = JTSectionSize / JTEntrySize;
+    uint8_t *JTSectionAddr = getSectionAddress(JTSectionID);
+    unsigned JTEntryOffset = 0;
+
+    assert((JTSectionSize % JTEntrySize) == 0 &&
+           "Jump-table section does not contain a whole number of stubs?");
+
+    for (unsigned i = 0; i < NumJTEntries; ++i) {
+      unsigned SymbolIndex =
+          Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
+      symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
+      StringRef IndirectSymbolName;
+      SI->getName(IndirectSymbolName);
+      uint8_t *JTEntryAddr = JTSectionAddr + JTEntryOffset;
+      createStubFunction(JTEntryAddr);
+      RelocationEntry RE(JTSectionID, JTEntryOffset + 1,
+                         MachO::GENERIC_RELOC_VANILLA, 0, true, 2);
+      addRelocationForSymbol(RE, IndirectSymbolName);
+      JTEntryOffset += JTEntrySize;
+    }
+  }
+
+  // Populate __pointers section.
+  void populatePointersSection(MachOObjectFile &Obj,
+                               const SectionRef &PTSection,
+                               unsigned PTSectionID) {
+    assert(!Obj.is64Bit() &&
+           "__pointers section not supported in 64-bit MachO.");
+
+    MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
+    MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
+    uint32_t PTSectionSize = Sec32.size;
+    unsigned FirstIndirectSymbol = Sec32.reserved1;
+    const unsigned PTEntrySize = 4;
+    unsigned NumPTEntries = PTSectionSize / PTEntrySize;
+    unsigned PTEntryOffset = 0;
+
+    assert((PTSectionSize % PTEntrySize) == 0 &&
+           "Pointers section does not contain a whole number of stubs?");
+
+    DEBUG(dbgs() << "Populating __pointers, Section ID " << PTSectionID << ", "
+                 << NumPTEntries << " entries, " << PTEntrySize
+                 << " bytes each:\n");
+
+    for (unsigned i = 0; i < NumPTEntries; ++i) {
+      unsigned SymbolIndex =
+          Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
+      symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
+      StringRef IndirectSymbolName;
+      SI->getName(IndirectSymbolName);
+      DEBUG(dbgs() << "  " << IndirectSymbolName << ": index " << SymbolIndex
+                   << ", PT offset: " << PTEntryOffset << "\n");
+      RelocationEntry RE(PTSectionID, PTEntryOffset,
+                         MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
+      addRelocationForSymbol(RE, IndirectSymbolName);
+      PTEntryOffset += PTEntrySize;
+    }
+  }
+
+  static section_iterator getSectionByAddress(const MachOObjectFile &Obj,
+                                              uint64_t Addr) {
+    section_iterator SI = Obj.section_begin();
+    section_iterator SE = Obj.section_end();
+
+    for (; SI != SE; ++SI) {
+      uint64_t SAddr, SSize;
+      SI->getAddress(SAddr);
+      SI->getSize(SSize);
+      if ((Addr >= SAddr) && (Addr < SAddr + SSize))
+        return SI;
+    }
+
+    return SE;
+  }
+};
+}
+
+#undef DEBUG_TYPE
+
+#endif // LLVM_RUNTIMEDYLDMACHOI386_H