llvm/lib/Target/AVR/AVRTargetObjectFile.cpp

   1 //===-- AVRTargetObjectFile.cpp - AVR Object Files ------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "AVRTargetObjectFile.h"
  10 #include "AVRTargetMachine.h"
  11
  12 #include "llvm/BinaryFormat/ELF.h"
  13 #include "llvm/IR/GlobalValue.h"
  14 #include "llvm/IR/Mangler.h"
  15 #include "llvm/MC/MCContext.h"
  16 #include "llvm/MC/MCSectionELF.h"
  17
  18 #include "AVR.h"
  19
  20 namespace llvm {
  21 void AVRTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM) {
  22   Base::Initialize(Ctx, TM);
  23   ProgmemDataSection =
  24       Ctx.getELFSection(".progmem.data", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  25   Progmem1DataSection =
  26       Ctx.getELFSection(".progmem1.data", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  27   Progmem2DataSection =
  28       Ctx.getELFSection(".progmem2.data", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  29   Progmem3DataSection =
  30       Ctx.getELFSection(".progmem3.data", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  31   Progmem4DataSection =
  32       Ctx.getELFSection(".progmem4.data", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  33   Progmem5DataSection =
  34       Ctx.getELFSection(".progmem5.data", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  35 }
  36
  37 MCSection *AVRTargetObjectFile::SelectSectionForGlobal(
  38     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
  39   // Global values in flash memory are placed in the progmem*.data section
  40   // unless they already have a user assigned section.
  41   const auto &AVRTM = static_cast<const AVRTargetMachine &>(TM);
  42   if (AVR::isProgramMemoryAddress(GO) && !GO->hasSection() &&
  43       Kind.isReadOnly()) {
  44     // The AVR subtarget should support LPM to access section '.progmem*.data'.
  45     if (!AVRTM.getSubtargetImpl()->hasLPM()) {
  46       // TODO: Get the global object's location in source file.
  47       getContext().reportError(
  48           SMLoc(),
  49           "Current AVR subtarget does not support accessing program memory");
  50       return Base::SelectSectionForGlobal(GO, Kind, TM);
  51     }
  52     // The AVR subtarget should support ELPM to access section
  53     // '.progmem[1|2|3|4|5].data'.
  54     if (!AVRTM.getSubtargetImpl()->hasELPM() &&
  55         AVR::getAddressSpace(GO) != AVR::ProgramMemory) {
  56       // TODO: Get the global object's location in source file.
  57       getContext().reportError(SMLoc(),
  58                                "Current AVR subtarget does not support "
  59                                "accessing extended program memory");
  60       return ProgmemDataSection;
  61     }
  62     switch (AVR::getAddressSpace(GO)) {
  63     case AVR::ProgramMemory: // address space 1
  64       return ProgmemDataSection;
  65     case AVR::ProgramMemory1: // address space 2
  66       return Progmem1DataSection;
  67     case AVR::ProgramMemory2: // address space 3
  68       return Progmem2DataSection;
  69     case AVR::ProgramMemory3: // address space 4
  70       return Progmem3DataSection;
  71     case AVR::ProgramMemory4: // address space 5
  72       return Progmem4DataSection;
  73     case AVR::ProgramMemory5: // address space 6
  74       return Progmem5DataSection;
  75     default:
  76       llvm_unreachable("unexpected program memory index");
  77     }
  78   }
  79
  80   // Otherwise, we work the same way as ELF.
  81   return Base::SelectSectionForGlobal(GO, Kind, TM);
  82 }
  83 } // end of namespace llvm