/src/keystone/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp

Source (jump to first uncovered line)
//===-- ARMELFObjectWriter.cpp - ARM ELF Writer ---------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "MCTargetDesc/ARMMCTargetDesc.h"
#include "MCTargetDesc/ARMFixupKinds.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm_ks;

namespace {
  class ARMELFObjectWriter : public MCELFObjectTargetWriter {
    enum { DefaultEABIVersion = 0x05000000U };
    unsigned GetRelocTypeInner(const MCValue &Target,
                               const MCFixup &Fixup,
                               bool IsPCRel) const;


  public:
    ARMELFObjectWriter(uint8_t OSABI);

    ~ARMELFObjectWriter() override;

    unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
                          const MCFixup &Fixup, bool IsPCRel) const override;

    bool needsRelocateWithSymbol(const MCSymbol &Sym,
                                 unsigned Type) const override;
  };
}

ARMELFObjectWriter::ARMELFObjectWriter(uint8_t OSABI)
  : MCELFObjectTargetWriter(/*Is64Bit*/ false, OSABI,
                            ELF::EM_ARM,
                            /*HasRelocationAddend*/ false) {}

ARMELFObjectWriter::~ARMELFObjectWriter() {}

bool ARMELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
                                                 unsigned Type) const {
  // FIXME: This is extremely conservative. This really needs to use a
  // whitelist with a clear explanation for why each realocation needs to
  // point to the symbol, not to the section.
  switch (Type) {
  default:
    return true;

  case ELF::R_ARM_PREL31:
  case ELF::R_ARM_ABS32:
    return false;
  }
}

// Need to examine the Fixup when determining whether to 
// emit the relocation as an explicit symbol or as a section relative
// offset
unsigned ARMELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
                                          const MCFixup &Fixup,
                                          bool IsPCRel) const {
  return GetRelocTypeInner(Target, Fixup, IsPCRel);
}

unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
                                               const MCFixup &Fixup,
                                               bool IsPCRel) const  {
  MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();

  unsigned Type = 0;
  if (IsPCRel) {
    switch ((unsigned)Fixup.getKind()) {
    default:
      report_fatal_error("unsupported relocation on symbol");
      return ELF::R_ARM_NONE;
    case FK_Data_4:
      switch (Modifier) {
      default: llvm_unreachable("Unsupported Modifier");
      case MCSymbolRefExpr::VK_None:
        Type = ELF::R_ARM_REL32;
        break;
      case MCSymbolRefExpr::VK_TLSGD:
        llvm_unreachable("unimplemented");
      case MCSymbolRefExpr::VK_GOTTPOFF:
        Type = ELF::R_ARM_TLS_IE32;
        break;
      case MCSymbolRefExpr::VK_ARM_GOT_PREL:
        Type = ELF::R_ARM_GOT_PREL;
        break;
      }
      break;
    case ARM::fixup_arm_blx:
    case ARM::fixup_arm_uncondbl:
      switch (Modifier) {
      case MCSymbolRefExpr::VK_PLT:
        Type = ELF::R_ARM_CALL;
        break;
      case MCSymbolRefExpr::VK_ARM_TLSCALL:
        Type = ELF::R_ARM_TLS_CALL;
        break;
      default:
        Type = ELF::R_ARM_CALL;
        break;
      }
      break;
    case ARM::fixup_arm_condbl:
    case ARM::fixup_arm_condbranch:
    case ARM::fixup_arm_uncondbranch:
      Type = ELF::R_ARM_JUMP24;
      break;
    case ARM::fixup_t2_condbranch:
    case ARM::fixup_t2_uncondbranch:
      Type = ELF::R_ARM_THM_JUMP24;
      break;
    case ARM::fixup_arm_movt_hi16:
      Type = ELF::R_ARM_MOVT_PREL;
      break;
    case ARM::fixup_arm_movw_lo16:
      Type = ELF::R_ARM_MOVW_PREL_NC;
      break;
    case ARM::fixup_t2_movt_hi16:
      Type = ELF::R_ARM_THM_MOVT_PREL;
      break;
    case ARM::fixup_t2_movw_lo16:
      Type = ELF::R_ARM_THM_MOVW_PREL_NC;
      break;
    case ARM::fixup_arm_thumb_bl:
    case ARM::fixup_arm_thumb_blx:
      switch (Modifier) {
      case MCSymbolRefExpr::VK_ARM_TLSCALL:
        Type = ELF::R_ARM_THM_TLS_CALL;
        break;
      default:
        Type = ELF::R_ARM_THM_CALL;
        break;
      }
      break;
    }
  } else {
    switch ((unsigned)Fixup.getKind()) {
    default:
      report_fatal_error("unsupported relocation on symbol");
      return ELF::R_ARM_NONE;
    case FK_Data_1:
      switch (Modifier) {
      default: llvm_unreachable("unsupported Modifier");
      case MCSymbolRefExpr::VK_None:
        Type = ELF::R_ARM_ABS8;
        break;
      }
      break;
    case FK_Data_2:
      switch (Modifier) {
      default: llvm_unreachable("unsupported modifier");
      case MCSymbolRefExpr::VK_None:
        Type = ELF::R_ARM_ABS16;
        break;
      }
      break;
    case FK_Data_4:
      switch (Modifier) {
      default: llvm_unreachable("Unsupported Modifier");
      case MCSymbolRefExpr::VK_ARM_NONE:
        Type = ELF::R_ARM_NONE;
        break;
      case MCSymbolRefExpr::VK_GOT:
        Type = ELF::R_ARM_GOT_BREL;
        break;
      case MCSymbolRefExpr::VK_TLSGD:
        Type = ELF::R_ARM_TLS_GD32;
        break;
      case MCSymbolRefExpr::VK_TPOFF:
        Type = ELF::R_ARM_TLS_LE32;
        break;
      case MCSymbolRefExpr::VK_GOTTPOFF:
        Type = ELF::R_ARM_TLS_IE32;
        break;
      case MCSymbolRefExpr::VK_None:
        Type = ELF::R_ARM_ABS32;
        break;
      case MCSymbolRefExpr::VK_GOTOFF:
        Type = ELF::R_ARM_GOTOFF32;
        break;
      case MCSymbolRefExpr::VK_ARM_GOT_PREL:
        Type = ELF::R_ARM_GOT_PREL;
        break;
      case MCSymbolRefExpr::VK_ARM_TARGET1:
        Type = ELF::R_ARM_TARGET1;
        break;
      case MCSymbolRefExpr::VK_ARM_TARGET2:
        Type = ELF::R_ARM_TARGET2;
        break;
      case MCSymbolRefExpr::VK_ARM_PREL31:
        Type = ELF::R_ARM_PREL31;
        break;
      case MCSymbolRefExpr::VK_ARM_SBREL:
        Type = ELF::R_ARM_SBREL32;
        break;
      case MCSymbolRefExpr::VK_ARM_TLSLDO:
        Type = ELF::R_ARM_TLS_LDO32;
        break;
      case MCSymbolRefExpr::VK_ARM_TLSCALL:
        Type = ELF::R_ARM_TLS_CALL;
        break;
      case MCSymbolRefExpr::VK_ARM_TLSDESC:
        Type = ELF::R_ARM_TLS_GOTDESC;
        break;
      case MCSymbolRefExpr::VK_ARM_TLSDESCSEQ:
        Type = ELF::R_ARM_TLS_DESCSEQ;
        break;
      }
      break;
    case ARM::fixup_arm_ldst_pcrel_12:
    case ARM::fixup_arm_pcrel_10:
    case ARM::fixup_arm_adr_pcrel_12:
    case ARM::fixup_arm_thumb_bl:
    case ARM::fixup_arm_thumb_cb:
    case ARM::fixup_arm_thumb_cp:
    case ARM::fixup_arm_thumb_br:
      llvm_unreachable("Unimplemented");
    case ARM::fixup_arm_condbranch:
    case ARM::fixup_arm_uncondbranch:
      Type = ELF::R_ARM_JUMP24;
      break;
    case ARM::fixup_arm_movt_hi16:
      Type = ELF::R_ARM_MOVT_ABS;
      break;
    case ARM::fixup_arm_movw_lo16:
      Type = ELF::R_ARM_MOVW_ABS_NC;
      break;
    case ARM::fixup_t2_movt_hi16:
      Type = ELF::R_ARM_THM_MOVT_ABS;
      break;
    case ARM::fixup_t2_movw_lo16:
      Type = ELF::R_ARM_THM_MOVW_ABS_NC;
      break;
    }
  }

  return Type;
}

MCObjectWriter *llvm_ks::createARMELFObjectWriter(raw_pwrite_stream &OS,
                                               uint8_t OSABI,
                                               bool IsLittleEndian) {
  MCELFObjectTargetWriter *MOTW = new ARMELFObjectWriter(OSABI);
  return createELFObjectWriter(MOTW, OS, IsLittleEndian);
}

Coverage Report

Created: 2025-07-15 06:22

Line	Count	Source (jump to first uncovered line)
1		//===-- ARMELFObjectWriter.cpp - ARM ELF Writer ---------------------------===//
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/ARMMCTargetDesc.h"
11		#include "MCTargetDesc/ARMFixupKinds.h"
12		#include "llvm/ADT/StringSwitch.h"
13		#include "llvm/MC/MCELFObjectWriter.h"
14		#include "llvm/MC/MCExpr.h"
15		#include "llvm/MC/MCSectionELF.h"
16		#include "llvm/MC/MCValue.h"
17		#include "llvm/Support/Debug.h"
18		#include "llvm/Support/ErrorHandling.h"
19		#include "llvm/Support/raw_ostream.h"
20
21		using namespace llvm_ks;
22
23		namespace {
24		class ARMELFObjectWriter : public MCELFObjectTargetWriter {
25		enum { DefaultEABIVersion = 0x05000000U };
26		unsigned GetRelocTypeInner(const MCValue &Target,
27		const MCFixup &Fixup,
28		bool IsPCRel) const;
29
30
31		public:
32		ARMELFObjectWriter(uint8_t OSABI);
33
34		~ARMELFObjectWriter() override;
35
36		unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
37		const MCFixup &Fixup, bool IsPCRel) const override;
38
39		bool needsRelocateWithSymbol(const MCSymbol &Sym,
40		unsigned Type) const override;
41		};
42		}
43
44		ARMELFObjectWriter::ARMELFObjectWriter(uint8_t OSABI)
45	61.7k	: MCELFObjectTargetWriter(/Is64Bit/ false, OSABI,
46	61.7k	ELF::EM_ARM,
47	61.7k	/HasRelocationAddend/ false) {}
48
49		ARMELFObjectWriter::~ARMELFObjectWriter() {}
50
51		bool ARMELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
52	55.2k	unsigned Type) const {
53		// FIXME: This is extremely conservative. This really needs to use a
54		// whitelist with a clear explanation for why each realocation needs to
55		// point to the symbol, not to the section.
56	55.2k	switch (Type) {
57	1.21k	default:
58	1.21k	return true;
59
60	0	case ELF::R_ARM_PREL31:
61	54.0k	case ELF::R_ARM_ABS32:
62	54.0k	return false;
63	55.2k	}
64	55.2k	}
65
66		// Need to examine the Fixup when determining whether to
67		// emit the relocation as an explicit symbol or as a section relative
68		// offset
69		unsigned ARMELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
70		const MCFixup &Fixup,
71	59.2k	bool IsPCRel) const {
72	59.2k	return GetRelocTypeInner(Target, Fixup, IsPCRel);
73	59.2k	}
74
75		unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
76		const MCFixup &Fixup,
77	59.2k	bool IsPCRel) const {
78	59.2k	MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
79
80	59.2k	unsigned Type = 0;
81	59.2k	if (IsPCRel) {
82	4.58k	switch ((unsigned)Fixup.getKind()) {
83	0	default:
84	0	report_fatal_error("unsupported relocation on symbol");
85	0	return ELF::R_ARM_NONE;
86	2.34k	case FK_Data_4:
87	2.34k	switch (Modifier) {
88	0	default: llvm_unreachable("Unsupported Modifier");
89	2.34k	case MCSymbolRefExpr::VK_None:
90	2.34k	Type = ELF::R_ARM_REL32;
91	2.34k	break;
92	0	case MCSymbolRefExpr::VK_TLSGD:
93	0	llvm_unreachable("unimplemented");
94	0	case MCSymbolRefExpr::VK_GOTTPOFF:
95	0	Type = ELF::R_ARM_TLS_IE32;
96	0	break;
97	0	case MCSymbolRefExpr::VK_ARM_GOT_PREL:
98	0	Type = ELF::R_ARM_GOT_PREL;
99	0	break;
100	2.34k	}
101	2.34k	break;
102	2.34k	case ARM::fixup_arm_blx:
103	403	case ARM::fixup_arm_uncondbl:
104	403	switch (Modifier) {
105	0	case MCSymbolRefExpr::VK_PLT:
106	0	Type = ELF::R_ARM_CALL;
107	0	break;
108	0	case MCSymbolRefExpr::VK_ARM_TLSCALL:
109	0	Type = ELF::R_ARM_TLS_CALL;
110	0	break;
111	403	default:
112	403	Type = ELF::R_ARM_CALL;
113	403	break;
114	403	}
115	403	break;
116	403	case ARM::fixup_arm_condbl:
117	419	case ARM::fixup_arm_condbranch:
118	804	case ARM::fixup_arm_uncondbranch:
119	804	Type = ELF::R_ARM_JUMP24;
120	804	break;
121	63	case ARM::fixup_t2_condbranch:
122	228	case ARM::fixup_t2_uncondbranch:
123	228	Type = ELF::R_ARM_THM_JUMP24;
124	228	break;
125	0	case ARM::fixup_arm_movt_hi16:
126	0	Type = ELF::R_ARM_MOVT_PREL;
127	0	break;
128	0	case ARM::fixup_arm_movw_lo16:
129	0	Type = ELF::R_ARM_MOVW_PREL_NC;
130	0	break;
131	0	case ARM::fixup_t2_movt_hi16:
132	0	Type = ELF::R_ARM_THM_MOVT_PREL;
133	0	break;
134	0	case ARM::fixup_t2_movw_lo16:
135	0	Type = ELF::R_ARM_THM_MOVW_PREL_NC;
136	0	break;
137	692	case ARM::fixup_arm_thumb_bl:
138	803	case ARM::fixup_arm_thumb_blx:
139	803	switch (Modifier) {
140	0	case MCSymbolRefExpr::VK_ARM_TLSCALL:
141	0	Type = ELF::R_ARM_THM_TLS_CALL;
142	0	break;
143	803	default:
144	803	Type = ELF::R_ARM_THM_CALL;
145	803	break;
146	803	}
147	803	break;
148	4.58k	}
149	54.6k	} else {
150	54.6k	switch ((unsigned)Fixup.getKind()) {
151	0	default:
152	0	report_fatal_error("unsupported relocation on symbol");
153	0	return ELF::R_ARM_NONE;
154	413	case FK_Data_1:
155	413	switch (Modifier) {
156	0	default: llvm_unreachable("unsupported Modifier");
157	413	case MCSymbolRefExpr::VK_None:
158	413	Type = ELF::R_ARM_ABS8;
159	413	break;
160	413	}
161	413	break;
162	413	case FK_Data_2:
163	259	switch (Modifier) {
164	0	default: llvm_unreachable("unsupported modifier");
165	259	case MCSymbolRefExpr::VK_None:
166	259	Type = ELF::R_ARM_ABS16;
167	259	break;
168	259	}
169	259	break;
170	54.0k	case FK_Data_4:
171	54.0k	switch (Modifier) {
172	0	default: llvm_unreachable("Unsupported Modifier");
173	0	case MCSymbolRefExpr::VK_ARM_NONE:
174	0	Type = ELF::R_ARM_NONE;
175	0	break;
176	0	case MCSymbolRefExpr::VK_GOT:
177	0	Type = ELF::R_ARM_GOT_BREL;
178	0	break;
179	0	case MCSymbolRefExpr::VK_TLSGD:
180	0	Type = ELF::R_ARM_TLS_GD32;
181	0	break;
182	0	case MCSymbolRefExpr::VK_TPOFF:
183	0	Type = ELF::R_ARM_TLS_LE32;
184	0	break;
185	0	case MCSymbolRefExpr::VK_GOTTPOFF:
186	0	Type = ELF::R_ARM_TLS_IE32;
187	0	break;
188	54.0k	case MCSymbolRefExpr::VK_None:
189	54.0k	Type = ELF::R_ARM_ABS32;
190	54.0k	break;
191	0	case MCSymbolRefExpr::VK_GOTOFF:
192	0	Type = ELF::R_ARM_GOTOFF32;
193	0	break;
194	0	case MCSymbolRefExpr::VK_ARM_GOT_PREL:
195	0	Type = ELF::R_ARM_GOT_PREL;
196	0	break;
197	0	case MCSymbolRefExpr::VK_ARM_TARGET1:
198	0	Type = ELF::R_ARM_TARGET1;
199	0	break;
200	0	case MCSymbolRefExpr::VK_ARM_TARGET2:
201	0	Type = ELF::R_ARM_TARGET2;
202	0	break;
203	0	case MCSymbolRefExpr::VK_ARM_PREL31:
204	0	Type = ELF::R_ARM_PREL31;
205	0	break;
206	0	case MCSymbolRefExpr::VK_ARM_SBREL:
207	0	Type = ELF::R_ARM_SBREL32;
208	0	break;
209	0	case MCSymbolRefExpr::VK_ARM_TLSLDO:
210	0	Type = ELF::R_ARM_TLS_LDO32;
211	0	break;
212	0	case MCSymbolRefExpr::VK_ARM_TLSCALL:
213	0	Type = ELF::R_ARM_TLS_CALL;
214	0	break;
215	0	case MCSymbolRefExpr::VK_ARM_TLSDESC:
216	0	Type = ELF::R_ARM_TLS_GOTDESC;
217	0	break;
218	0	case MCSymbolRefExpr::VK_ARM_TLSDESCSEQ:
219	0	Type = ELF::R_ARM_TLS_DESCSEQ;
220	0	break;
221	54.0k	}
222	54.0k	break;
223	54.0k	case ARM::fixup_arm_ldst_pcrel_12:
224	0	case ARM::fixup_arm_pcrel_10:
225	0	case ARM::fixup_arm_adr_pcrel_12:
226	0	case ARM::fixup_arm_thumb_bl:
227	0	case ARM::fixup_arm_thumb_cb:
228	0	case ARM::fixup_arm_thumb_cp:
229	0	case ARM::fixup_arm_thumb_br:
230	0	llvm_unreachable("Unimplemented");
231	0	case ARM::fixup_arm_condbranch:
232	0	case ARM::fixup_arm_uncondbranch:
233	0	Type = ELF::R_ARM_JUMP24;
234	0	break;
235	0	case ARM::fixup_arm_movt_hi16:
236	0	Type = ELF::R_ARM_MOVT_ABS;
237	0	break;
238	0	case ARM::fixup_arm_movw_lo16:
239	0	Type = ELF::R_ARM_MOVW_ABS_NC;
240	0	break;
241	0	case ARM::fixup_t2_movt_hi16:
242	0	Type = ELF::R_ARM_THM_MOVT_ABS;
243	0	break;
244	0	case ARM::fixup_t2_movw_lo16:
245	0	Type = ELF::R_ARM_THM_MOVW_ABS_NC;
246	0	break;
247	54.6k	}
248	54.6k	}
249
250	59.2k	return Type;
251	59.2k	}
252
253		MCObjectWriter *llvm_ks::createARMELFObjectWriter(raw_pwrite_stream &OS,
254		uint8_t OSABI,
255	61.7k	bool IsLittleEndian) {
256	61.7k	MCELFObjectTargetWriter *MOTW = new ARMELFObjectWriter(OSABI);
257	61.7k	return createELFObjectWriter(MOTW, OS, IsLittleEndian);
258	61.7k	}