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/MCObjectWriter.h"
18 #include "llvm/MC/MCValue.h"
19 #include "llvm/MC/MCWinCOFFObjectWriter.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include <cassert>
23 
24 using namespace llvm;
25 
26 namespace {
27 
28 class ARMWinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
29 public:
30   ARMWinCOFFObjectWriter(bool Is64Bit)
31     : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARMNT) {
32     assert(!Is64Bit && "AArch64 support not yet implemented");
33   }
34 
35   ~ARMWinCOFFObjectWriter() override = default;
36 
37   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
38                         const MCFixup &Fixup, bool IsCrossSection,
39                         const MCAsmBackend &MAB) const override;
40 
41   bool recordRelocation(const MCFixup &) const override;
42 };
43 
44 } // end anonymous namespace
45 
46 unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
47                                               const MCValue &Target,
48                                               const MCFixup &Fixup,
49                                               bool IsCrossSection,
50                                               const MCAsmBackend &MAB) const {
51   assert(getMachine() == COFF::IMAGE_FILE_MACHINE_ARMNT &&
52          "AArch64 support not yet implemented");
53 
54   MCSymbolRefExpr::VariantKind Modifier =
55     Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
56 
57   switch (static_cast<unsigned>(Fixup.getKind())) {
58   default: {
59     const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
60     report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
61   }
62   case FK_Data_4:
63     switch (Modifier) {
64     case MCSymbolRefExpr::VK_COFF_IMGREL32:
65       return COFF::IMAGE_REL_ARM_ADDR32NB;
66     case MCSymbolRefExpr::VK_SECREL:
67       return COFF::IMAGE_REL_ARM_SECREL;
68     default:
69       return COFF::IMAGE_REL_ARM_ADDR32;
70     }
71   case FK_SecRel_2:
72     return COFF::IMAGE_REL_ARM_SECTION;
73   case FK_SecRel_4:
74     return COFF::IMAGE_REL_ARM_SECREL;
75   case ARM::fixup_t2_condbranch:
76     return COFF::IMAGE_REL_ARM_BRANCH20T;
77   case ARM::fixup_t2_uncondbranch:
78   case ARM::fixup_arm_thumb_bl:
79     return COFF::IMAGE_REL_ARM_BRANCH24T;
80   case ARM::fixup_arm_thumb_blx:
81     return COFF::IMAGE_REL_ARM_BLX23T;
82   case ARM::fixup_t2_movw_lo16:
83   case ARM::fixup_t2_movt_hi16:
84     return COFF::IMAGE_REL_ARM_MOV32T;
85   }
86 }
87 
88 bool ARMWinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
89   return static_cast<unsigned>(Fixup.getKind()) != ARM::fixup_t2_movt_hi16;
90 }
91 
92 namespace llvm {
93 
94 std::unique_ptr<MCObjectTargetWriter>
95 createARMWinCOFFObjectWriter(bool Is64Bit) {
96   return llvm::make_unique<ARMWinCOFFObjectWriter>(Is64Bit);
97 }
98 
99 } // end namespace llvm
100