XCoreTargetObjectFile.cpp revision 309124 
1//===-- XCoreTargetObjectFile.cpp - XCore object files --------------------===//
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 "XCoreTargetObjectFile.h"
11#include "XCoreSubtarget.h"
12#include "llvm/IR/DataLayout.h"
13#include "llvm/MC/MCContext.h"
14#include "llvm/MC/MCSectionELF.h"
15#include "llvm/Support/ELF.h"
16#include "llvm/Target/TargetMachine.h"
17
18using namespace llvm;
19
20
21void XCoreTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){
22  TargetLoweringObjectFileELF::Initialize(Ctx, TM);
23
24  BSSSection = Ctx.getELFSection(".dp.bss", ELF::SHT_NOBITS,
25                                 ELF::SHF_ALLOC | ELF::SHF_WRITE |
26                                     ELF::XCORE_SHF_DP_SECTION);
27  BSSSectionLarge = Ctx.getELFSection(".dp.bss.large", ELF::SHT_NOBITS,
28                                      ELF::SHF_ALLOC | ELF::SHF_WRITE |
29                                          ELF::XCORE_SHF_DP_SECTION);
30  DataSection = Ctx.getELFSection(".dp.data", ELF::SHT_PROGBITS,
31                                  ELF::SHF_ALLOC | ELF::SHF_WRITE |
32                                      ELF::XCORE_SHF_DP_SECTION);
33  DataSectionLarge = Ctx.getELFSection(".dp.data.large", ELF::SHT_PROGBITS,
34                                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
35                                           ELF::XCORE_SHF_DP_SECTION);
36  DataRelROSection = Ctx.getELFSection(".dp.rodata", ELF::SHT_PROGBITS,
37                                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
38                                           ELF::XCORE_SHF_DP_SECTION);
39  DataRelROSectionLarge = Ctx.getELFSection(
40      ".dp.rodata.large", ELF::SHT_PROGBITS,
41      ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::XCORE_SHF_DP_SECTION);
42  ReadOnlySection =
43      Ctx.getELFSection(".cp.rodata", ELF::SHT_PROGBITS,
44                        ELF::SHF_ALLOC | ELF::XCORE_SHF_CP_SECTION);
45  ReadOnlySectionLarge =
46      Ctx.getELFSection(".cp.rodata.large", ELF::SHT_PROGBITS,
47                        ELF::SHF_ALLOC | ELF::XCORE_SHF_CP_SECTION);
48  MergeableConst4Section = Ctx.getELFSection(
49      ".cp.rodata.cst4", ELF::SHT_PROGBITS,
50      ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 4, "");
51  MergeableConst8Section = Ctx.getELFSection(
52      ".cp.rodata.cst8", ELF::SHT_PROGBITS,
53      ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 8, "");
54  MergeableConst16Section = Ctx.getELFSection(
55      ".cp.rodata.cst16", ELF::SHT_PROGBITS,
56      ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 16, "");
57  CStringSection =
58      Ctx.getELFSection(".cp.rodata.string", ELF::SHT_PROGBITS,
59                        ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS |
60                            ELF::XCORE_SHF_CP_SECTION);
61  // TextSection       - see MObjectFileInfo.cpp
62  // StaticCtorSection - see MObjectFileInfo.cpp
63  // StaticDtorSection - see MObjectFileInfo.cpp
64 }
65
66static unsigned getXCoreSectionType(SectionKind K) {
67  if (K.isBSS())
68    return ELF::SHT_NOBITS;
69  return ELF::SHT_PROGBITS;
70}
71
72static unsigned getXCoreSectionFlags(SectionKind K, bool IsCPRel) {
73  unsigned Flags = 0;
74
75  if (!K.isMetadata())
76    Flags |= ELF::SHF_ALLOC;
77
78  if (K.isText())
79    Flags |= ELF::SHF_EXECINSTR;
80  else if (IsCPRel)
81    Flags |= ELF::XCORE_SHF_CP_SECTION;
82  else
83    Flags |= ELF::XCORE_SHF_DP_SECTION;
84
85  if (K.isWriteable())
86    Flags |= ELF::SHF_WRITE;
87
88  if (K.isMergeableCString() || K.isMergeableConst4() ||
89      K.isMergeableConst8() || K.isMergeableConst16())
90    Flags |= ELF::SHF_MERGE;
91
92  if (K.isMergeableCString())
93    Flags |= ELF::SHF_STRINGS;
94
95  return Flags;
96}
97
98MCSection *
99XCoreTargetObjectFile::getExplicitSectionGlobal(const GlobalValue *GV,
100                                                SectionKind Kind, Mangler &Mang,
101                                                const TargetMachine &TM) const {
102  StringRef SectionName = GV->getSection();
103  // Infer section flags from the section name if we can.
104  bool IsCPRel = SectionName.startswith(".cp.");
105  if (IsCPRel && !Kind.isReadOnly())
106    report_fatal_error("Using .cp. section for writeable object.");
107  return getContext().getELFSection(SectionName, getXCoreSectionType(Kind),
108                                    getXCoreSectionFlags(Kind, IsCPRel));
109}
110
111MCSection *
112XCoreTargetObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
113                                              SectionKind Kind, Mangler &Mang,
114                                              const TargetMachine &TM) const {
115
116  bool UseCPRel = GV->isLocalLinkage(GV->getLinkage());
117
118  if (Kind.isText())                    return TextSection;
119  if (UseCPRel) {
120    if (Kind.isMergeable1ByteCString()) return CStringSection;
121    if (Kind.isMergeableConst4())       return MergeableConst4Section;
122    if (Kind.isMergeableConst8())       return MergeableConst8Section;
123    if (Kind.isMergeableConst16())      return MergeableConst16Section;
124  }
125  Type *ObjType = GV->getValueType();
126  auto &DL = GV->getParent()->getDataLayout();
127  if (TM.getCodeModel() == CodeModel::Small || !ObjType->isSized() ||
128      DL.getTypeAllocSize(ObjType) < CodeModelLargeSize) {
129    if (Kind.isReadOnly())              return UseCPRel? ReadOnlySection
130                                                       : DataRelROSection;
131    if (Kind.isBSS() || Kind.isCommon())return BSSSection;
132    if (Kind.isData())
133      return DataSection;
134    if (Kind.isReadOnlyWithRel())       return DataRelROSection;
135  } else {
136    if (Kind.isReadOnly())              return UseCPRel? ReadOnlySectionLarge
137                                                       : DataRelROSectionLarge;
138    if (Kind.isBSS() || Kind.isCommon())return BSSSectionLarge;
139    if (Kind.isData())
140      return DataSectionLarge;
141    if (Kind.isReadOnlyWithRel())       return DataRelROSectionLarge;
142  }
143
144  assert((Kind.isThreadLocal() || Kind.isCommon()) && "Unknown section kind");
145  report_fatal_error("Target does not support TLS or Common sections");
146}
147
148MCSection *XCoreTargetObjectFile::getSectionForConstant(const DataLayout &DL,
149                                                        SectionKind Kind,
150                                                        const Constant *C,
151                                                        unsigned &Align) const {
152  if (Kind.isMergeableConst4())           return MergeableConst4Section;
153  if (Kind.isMergeableConst8())           return MergeableConst8Section;
154  if (Kind.isMergeableConst16())          return MergeableConst16Section;
155  assert((Kind.isReadOnly() || Kind.isReadOnlyWithRel()) &&
156         "Unknown section kind");
157  // We assume the size of the object is never greater than CodeModelLargeSize.
158  // To handle CodeModelLargeSize changes to AsmPrinter would be required.
159  return ReadOnlySection;
160}
161