1 //===-- ARMWinCOFFObjectWriter.cpp - ARM Windows COFF Object Writer -- C++ -==//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "MCTargetDesc/ARMFixupKinds.h"
11 #include "llvm/ADT/Twine.h"
12 #include "llvm/BinaryFormat/COFF.h"
13 #include "llvm/MC/MCAsmBackend.h"
14 #include "llvm/MC/MCExpr.h"
15 #include "llvm/MC/MCFixup.h"
16 #include "llvm/MC/MCFixupKindInfo.h"
17 #include "llvm/MC/MCValue.h"
18 #include "llvm/MC/MCWinCOFFObjectWriter.h"
19 #include "llvm/Support/ErrorHandling.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include <cassert>
22 
23 using namespace llvm;
24 
25 namespace {
26 
27 class ARMWinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
28 public:
29   ARMWinCOFFObjectWriter(bool Is64Bit)
30     : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARMNT) {
31     assert(!Is64Bit && "AArch64 support not yet implemented");
32   }
33 
34   ~ARMWinCOFFObjectWriter() override = default;
35 
36   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
37                         const MCFixup &Fixup, bool IsCrossSection,
38                         const MCAsmBackend &MAB) const override;
39 
40   bool recordRelocation(const MCFixup &) const override;
41 };
42 
43 } // end anonymous namespace
44 
45 unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
46                                               const MCValue &Target,
47                                               const MCFixup &Fixup,
48                                               bool IsCrossSection,
49                                               const MCAsmBackend &MAB) const {
50   assert(getMachine() == COFF::IMAGE_FILE_MACHINE_ARMNT &&
51          "AArch64 support not yet implemented");
52 
53   MCSymbolRefExpr::VariantKind Modifier =
54     Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
55 
56   switch (static_cast<unsigned>(Fixup.getKind())) {
57   default: {
58     const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
59     report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
60   }
61   case FK_Data_4:
62     switch (Modifier) {
63     case MCSymbolRefExpr::VK_COFF_IMGREL32:
64       return COFF::IMAGE_REL_ARM_ADDR32NB;
65     case MCSymbolRefExpr::VK_SECREL:
66       return COFF::IMAGE_REL_ARM_SECREL;
67     default:
68       return COFF::IMAGE_REL_ARM_ADDR32;
69     }
70   case FK_SecRel_2:
71     return COFF::IMAGE_REL_ARM_SECTION;
72   case FK_SecRel_4:
73     return COFF::IMAGE_REL_ARM_SECREL;
74   case ARM::fixup_t2_condbranch:
75     return COFF::IMAGE_REL_ARM_BRANCH20T;
76   case ARM::fixup_t2_uncondbranch:
77     return COFF::IMAGE_REL_ARM_BRANCH24T;
78   case ARM::fixup_arm_thumb_bl:
79   case ARM::fixup_arm_thumb_blx:
80     return COFF::IMAGE_REL_ARM_BLX23T;
81   case ARM::fixup_t2_movw_lo16:
82   case ARM::fixup_t2_movt_hi16:
83     return COFF::IMAGE_REL_ARM_MOV32T;
84   }
85 }
86 
87 bool ARMWinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
88   return static_cast<unsigned>(Fixup.getKind()) != ARM::fixup_t2_movt_hi16;
89 }
90 
91 namespace llvm {
92 
93 MCObjectWriter *createARMWinCOFFObjectWriter(raw_pwrite_stream &OS,
94                                              bool Is64Bit) {
95   MCWinCOFFObjectTargetWriter *MOTW = new ARMWinCOFFObjectWriter(Is64Bit);
96   return createWinCOFFObjectWriter(MOTW, OS);
97 }
98 
99 } // end namespace llvm
100