xref: /llvm-project/llvm/lib/Target/AVR/AVRTargetObjectFile.cpp (revision ed8019d9fbed2e6a6b08f8f73e9fa54a24f3ed52)
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
84