TargetLoweringObjectFile.h revision 11e9657eeb76dff6baaab1cbac0b1fb7e1abb439 
1//===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- 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// This file implements classes used to handle lowerings specific to common
11// object file formats.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
16#define LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
17
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/StringMap.h"
20#include "llvm/MC/SectionKind.h"
21
22namespace llvm {
23  class MCSection;
24  class MCContext;
25  class GlobalValue;
26  class Mangler;
27  class TargetMachine;
28
29class TargetLoweringObjectFile {
30  MCContext *Ctx;
31protected:
32
33  TargetLoweringObjectFile();
34
35  /// TextSection - Section directive for standard text.
36  ///
37  const MCSection *TextSection;
38
39  /// DataSection - Section directive for standard data.
40  ///
41  const MCSection *DataSection;
42
43  /// BSSSection - Section that is default initialized to zero.
44  const MCSection *BSSSection;
45
46  /// ReadOnlySection - Section that is readonly and can contain arbitrary
47  /// initialized data.  Targets are not required to have a readonly section.
48  /// If they don't, various bits of code will fall back to using the data
49  /// section for constants.
50  const MCSection *ReadOnlySection;
51
52  /// StaticCtorSection - This section contains the static constructor pointer
53  /// list.
54  const MCSection *StaticCtorSection;
55
56  /// StaticDtorSection - This section contains the static destructor pointer
57  /// list.
58  const MCSection *StaticDtorSection;
59
60  /// LSDASection - If exception handling is supported by the target, this is
61  /// the section the Language Specific Data Area information is emitted to.
62  const MCSection *LSDASection;
63
64  /// EHFrameSection - If exception handling is supported by the target, this is
65  /// the section the EH Frame is emitted to.
66  const MCSection *EHFrameSection;
67
68  // Dwarf sections for debug info.  If a target supports debug info, these must
69  // be set.
70  const MCSection *DwarfAbbrevSection;
71  const MCSection *DwarfInfoSection;
72  const MCSection *DwarfLineSection;
73  const MCSection *DwarfFrameSection;
74  const MCSection *DwarfPubNamesSection;
75  const MCSection *DwarfPubTypesSection;
76  const MCSection *DwarfDebugInlineSection;
77  const MCSection *DwarfStrSection;
78  const MCSection *DwarfLocSection;
79  const MCSection *DwarfARangesSection;
80  const MCSection *DwarfRangesSection;
81  const MCSection *DwarfMacroInfoSection;
82
83public:
84  // FIXME: NONPUB.
85  const MCSection *getOrCreateSection(const char *Name,
86                                      bool isDirective,
87                                      SectionKind K) const;
88public:
89
90  virtual ~TargetLoweringObjectFile();
91
92  /// Initialize - this method must be called before any actual lowering is
93  /// done.  This specifies the current context for codegen, and gives the
94  /// lowering implementations a chance to set up their default sections.
95  virtual void Initialize(MCContext &ctx, const TargetMachine &TM) {
96    Ctx = &ctx;
97  }
98
99
100  const MCSection *getTextSection() const { return TextSection; }
101  const MCSection *getDataSection() const { return DataSection; }
102  const MCSection *getStaticCtorSection() const { return StaticCtorSection; }
103  const MCSection *getStaticDtorSection() const { return StaticDtorSection; }
104  const MCSection *getLSDASection() const { return LSDASection; }
105  const MCSection *getEHFrameSection() const { return EHFrameSection; }
106  const MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
107  const MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
108  const MCSection *getDwarfLineSection() const { return DwarfLineSection; }
109  const MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
110  const MCSection *getDwarfPubNamesSection() const{return DwarfPubNamesSection;}
111  const MCSection *getDwarfPubTypesSection() const{return DwarfPubTypesSection;}
112  const MCSection *getDwarfDebugInlineSection() const {
113    return DwarfDebugInlineSection;
114  }
115  const MCSection *getDwarfStrSection() const { return DwarfStrSection; }
116  const MCSection *getDwarfLocSection() const { return DwarfLocSection; }
117  const MCSection *getDwarfARangesSection() const { return DwarfARangesSection;}
118  const MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
119  const MCSection *getDwarfMacroInfoSection() const {
120    return DwarfMacroInfoSection;
121  }
122
123  /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively
124  /// decide not to emit the UsedDirective for some symbols in llvm.used.
125  /// FIXME: REMOVE this (rdar://7071300)
126  virtual bool shouldEmitUsedDirectiveFor(const GlobalValue *GV,
127                                          Mangler *) const {
128    return GV != 0;
129  }
130
131  /// getSectionForConstant - Given a constant with the SectionKind, return a
132  /// section that it should be placed in.
133  virtual const MCSection *getSectionForConstant(SectionKind Kind) const;
134
135  /// getKindForNamedSection - If this target wants to be able to override
136  /// section flags based on the name of the section specified for a global
137  /// variable, it can implement this.  This is used on ELF systems so that
138  /// ".tbss" gets the TLS bit set etc.
139  virtual SectionKind getKindForNamedSection(const char *Section,
140                                             SectionKind K) const {
141    return K;
142  }
143
144  /// SectionForGlobal - This method computes the appropriate section to emit
145  /// the specified global variable or function definition.  This should not
146  /// be passed external (or available externally) globals.
147  const MCSection *SectionForGlobal(const GlobalValue *GV,
148                                    Mangler *Mang,
149                                    const TargetMachine &TM) const;
150
151  /// getSpecialCasedSectionGlobals - Allow the target to completely override
152  /// section assignment of a global.
153  /// FIXME: ELIMINATE this by making PIC16 implement ADDRESS with
154  /// getFlagsForNamedSection.
155  virtual const MCSection *
156  getSpecialCasedSectionGlobals(const GlobalValue *GV, Mangler *Mang,
157                                SectionKind Kind) const {
158    return 0;
159  }
160
161  /// getSectionFlagsAsString - Turn the flags in the specified SectionKind
162  /// into a string that can be printed to the assembly file after the
163  /// ".section foo" part of a section directive.
164  virtual void getSectionFlagsAsString(SectionKind Kind,
165                                       SmallVectorImpl<char> &Str) const {
166  }
167
168protected:
169  virtual const MCSection *
170  SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
171                         Mangler *Mang, const TargetMachine &TM) const;
172};
173
174
175
176
177class TargetLoweringObjectFileELF : public TargetLoweringObjectFile {
178  bool AtIsCommentChar;  // True if @ is the comment character on this target.
179  bool HasCrazyBSS;
180protected:
181  /// TLSDataSection - Section directive for Thread Local data.
182  ///
183  const MCSection *TLSDataSection;        // Defaults to ".tdata".
184
185  /// TLSBSSSection - Section directive for Thread Local uninitialized data.
186  /// Null if this target doesn't support a BSS section.
187  ///
188  const MCSection *TLSBSSSection;         // Defaults to ".tbss".
189
190  const MCSection *CStringSection;
191
192  const MCSection *DataRelSection;
193  const MCSection *DataRelLocalSection;
194  const MCSection *DataRelROSection;
195  const MCSection *DataRelROLocalSection;
196
197  const MCSection *MergeableConst4Section;
198  const MCSection *MergeableConst8Section;
199  const MCSection *MergeableConst16Section;
200public:
201  /// ELF Constructor - AtIsCommentChar is true if the CommentCharacter from TAI
202  /// is "@".
203  TargetLoweringObjectFileELF(bool atIsCommentChar = false,
204                              // FIXME: REMOVE AFTER UNIQUING IS FIXED.
205                              bool hasCrazyBSS = false)
206    : AtIsCommentChar(atIsCommentChar), HasCrazyBSS(hasCrazyBSS) {}
207
208  virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
209
210
211  /// getSectionForConstant - Given a constant with the SectionKind, return a
212  /// section that it should be placed in.
213  virtual const MCSection *getSectionForConstant(SectionKind Kind) const;
214
215  virtual SectionKind getKindForNamedSection(const char *Section,
216                                             SectionKind K) const;
217  void getSectionFlagsAsString(SectionKind Kind,
218                               SmallVectorImpl<char> &Str) const;
219
220  virtual const MCSection *
221  SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
222                         Mangler *Mang, const TargetMachine &TM) const;
223};
224
225
226
227class TargetLoweringObjectFileMachO : public TargetLoweringObjectFile {
228  const MCSection *CStringSection;
229  const MCSection *TextCoalSection;
230  const MCSection *ConstTextCoalSection;
231  const MCSection *ConstDataCoalSection;
232  const MCSection *ConstDataSection;
233  const MCSection *DataCoalSection;
234  const MCSection *FourByteConstantSection;
235  const MCSection *EightByteConstantSection;
236  const MCSection *SixteenByteConstantSection;
237public:
238
239  virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
240
241  virtual const MCSection *
242  SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
243                         Mangler *Mang, const TargetMachine &TM) const;
244
245  virtual const MCSection *getSectionForConstant(SectionKind Kind) const;
246
247  /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively
248  /// decide not to emit the UsedDirective for some symbols in llvm.used.
249  /// FIXME: REMOVE this (rdar://7071300)
250  virtual bool shouldEmitUsedDirectiveFor(const GlobalValue *GV,
251                                          Mangler *) const;
252
253  /// getMachOSection - Return the MCSection for the specified mach-o section.
254  /// FIXME: Switch this to a semantic view eventually.
255  const MCSection *getMachOSection(const char *Name, bool isDirective,
256                                   SectionKind K);
257};
258
259
260
261class TargetLoweringObjectFileCOFF : public TargetLoweringObjectFile {
262public:
263  virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
264
265  virtual void getSectionFlagsAsString(SectionKind Kind,
266                                       SmallVectorImpl<char> &Str) const;
267
268  virtual const MCSection *
269  SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
270                         Mangler *Mang, const TargetMachine &TM) const;
271
272  /// getCOFFSection - Return the MCSection for the specified COFF section.
273  /// FIXME: Switch this to a semantic view eventually.
274  const MCSection *getCOFFSection(const char *Name, bool isDirective,
275                                  SectionKind K);
276};
277
278} // end namespace llvm
279
280#endif
281