TargetLoweringObjectFile.h revision 4c0c446d7458ffcfbe108ea71f1915f387e150e7 
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/StringRef.h"
19#include "llvm/MC/SectionKind.h"
20
21namespace llvm {
22  class MachineModuleInfo;
23  class Mangler;
24  class MCAsmInfo;
25  class MCContext;
26  class MCExpr;
27  class MCSection;
28  class MCSectionMachO;
29  class MCSymbol;
30  class MCStreamer;
31  class GlobalValue;
32  class TargetMachine;
33
34class TargetLoweringObjectFile {
35  MCContext *Ctx;
36
37  TargetLoweringObjectFile(const TargetLoweringObjectFile&); // DO NOT IMPLEMENT
38  void operator=(const TargetLoweringObjectFile&);           // DO NOT IMPLEMENT
39protected:
40
41  TargetLoweringObjectFile();
42
43  /// TextSection - Section directive for standard text.
44  ///
45  const MCSection *TextSection;
46
47  /// DataSection - Section directive for standard data.
48  ///
49  const MCSection *DataSection;
50
51  /// BSSSection - Section that is default initialized to zero.
52  const MCSection *BSSSection;
53
54  /// ReadOnlySection - Section that is readonly and can contain arbitrary
55  /// initialized data.  Targets are not required to have a readonly section.
56  /// If they don't, various bits of code will fall back to using the data
57  /// section for constants.
58  const MCSection *ReadOnlySection;
59
60  /// StaticCtorSection - This section contains the static constructor pointer
61  /// list.
62  const MCSection *StaticCtorSection;
63
64  /// StaticDtorSection - This section contains the static destructor pointer
65  /// list.
66  const MCSection *StaticDtorSection;
67
68  /// LSDASection - If exception handling is supported by the target, this is
69  /// the section the Language Specific Data Area information is emitted to.
70  const MCSection *LSDASection;
71
72  /// CompactUnwindSection - If exception handling is supported by the target
73  /// and the target can support a compact representation of the CIE and FDE,
74  /// this is the section to emit them into.
75  const MCSection *CompactUnwindSection;
76
77  // Dwarf sections for debug info.  If a target supports debug info, these must
78  // be set.
79  const MCSection *DwarfAbbrevSection;
80  const MCSection *DwarfInfoSection;
81  const MCSection *DwarfLineSection;
82  const MCSection *DwarfFrameSection;
83  const MCSection *DwarfPubNamesSection;
84  const MCSection *DwarfPubTypesSection;
85  const MCSection *DwarfDebugInlineSection;
86  const MCSection *DwarfStrSection;
87  const MCSection *DwarfLocSection;
88  const MCSection *DwarfARangesSection;
89  const MCSection *DwarfRangesSection;
90  const MCSection *DwarfMacroInfoSection;
91
92  // Extra TLS Variable Data section.  If the target needs to put additional
93  // information for a TLS variable, it'll go here.
94  const MCSection *TLSExtraDataSection;
95
96  /// CommDirectiveSupportsAlignment - True if .comm supports alignment.  This
97  /// is a hack for as long as we support 10.4 Tiger, whose assembler doesn't
98  /// support alignment on comm.
99  bool CommDirectiveSupportsAlignment;
100
101  /// SupportsWeakEmptyEHFrame - True if target object file supports a
102  /// weak_definition of constant 0 for an omitted EH frame.
103  bool SupportsWeakOmittedEHFrame;
104
105  /// IsFunctionEHFrameSymbolPrivate - This flag is set to true if the
106  /// "EH_frame" symbol for EH information should be an assembler temporary (aka
107  /// private linkage, aka an L or .L label) or false if it should be a normal
108  /// non-.globl label.  This defaults to true.
109  bool IsFunctionEHFrameSymbolPrivate;
110
111public:
112  MCContext &getContext() const { return *Ctx; }
113
114  virtual ~TargetLoweringObjectFile();
115
116  /// Initialize - this method must be called before any actual lowering is
117  /// done.  This specifies the current context for codegen, and gives the
118  /// lowering implementations a chance to set up their default sections.
119  virtual void Initialize(MCContext &ctx, const TargetMachine &TM) {
120    Ctx = &ctx;
121  }
122
123  bool isFunctionEHFrameSymbolPrivate() const {
124    return IsFunctionEHFrameSymbolPrivate;
125  }
126  bool getSupportsWeakOmittedEHFrame() const {
127    return SupportsWeakOmittedEHFrame;
128  }
129  bool getCommDirectiveSupportsAlignment() const {
130    return CommDirectiveSupportsAlignment;
131  }
132
133  const MCSection *getTextSection() const { return TextSection; }
134  const MCSection *getDataSection() const { return DataSection; }
135  const MCSection *getBSSSection() const { return BSSSection; }
136  const MCSection *getStaticCtorSection() const { return StaticCtorSection; }
137  const MCSection *getStaticDtorSection() const { return StaticDtorSection; }
138  const MCSection *getLSDASection() const { return LSDASection; }
139  const MCSection *getCompactUnwindSection() const{return CompactUnwindSection;}
140  virtual const MCSection *getEHFrameSection() const = 0;
141  virtual void emitPersonalityValue(MCStreamer &Streamer,
142                                    const TargetMachine &TM,
143                                    const MCSymbol *Sym) const;
144  const MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
145  const MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
146  const MCSection *getDwarfLineSection() const { return DwarfLineSection; }
147  const MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
148  const MCSection *getDwarfPubNamesSection() const{return DwarfPubNamesSection;}
149  const MCSection *getDwarfPubTypesSection() const{return DwarfPubTypesSection;}
150  const MCSection *getDwarfDebugInlineSection() const {
151    return DwarfDebugInlineSection;
152  }
153  const MCSection *getDwarfStrSection() const { return DwarfStrSection; }
154  const MCSection *getDwarfLocSection() const { return DwarfLocSection; }
155  const MCSection *getDwarfARangesSection() const { return DwarfARangesSection;}
156  const MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
157  const MCSection *getDwarfMacroInfoSection() const {
158    return DwarfMacroInfoSection;
159  }
160  const MCSection *getTLSExtraDataSection() const {
161    return TLSExtraDataSection;
162  }
163  virtual const MCSection *getWin64EHFuncTableSection(StringRef suffix)const=0;
164  virtual const MCSection *getWin64EHTableSection(StringRef suffix) const = 0;
165
166  /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively
167  /// decide not to emit the UsedDirective for some symbols in llvm.used.
168  /// FIXME: REMOVE this (rdar://7071300)
169  virtual bool shouldEmitUsedDirectiveFor(const GlobalValue *GV,
170                                          Mangler *) const {
171    return GV != 0;
172  }
173
174  /// getSectionForConstant - Given a constant with the SectionKind, return a
175  /// section that it should be placed in.
176  virtual const MCSection *getSectionForConstant(SectionKind Kind) const;
177
178  /// getKindForGlobal - Classify the specified global variable into a set of
179  /// target independent categories embodied in SectionKind.
180  static SectionKind getKindForGlobal(const GlobalValue *GV,
181                                      const TargetMachine &TM);
182
183  /// SectionForGlobal - This method computes the appropriate section to emit
184  /// the specified global variable or function definition.  This should not
185  /// be passed external (or available externally) globals.
186  const MCSection *SectionForGlobal(const GlobalValue *GV,
187                                    SectionKind Kind, Mangler *Mang,
188                                    const TargetMachine &TM) const;
189
190  /// SectionForGlobal - This method computes the appropriate section to emit
191  /// the specified global variable or function definition.  This should not
192  /// be passed external (or available externally) globals.
193  const MCSection *SectionForGlobal(const GlobalValue *GV,
194                                    Mangler *Mang,
195                                    const TargetMachine &TM) const {
196    return SectionForGlobal(GV, getKindForGlobal(GV, TM), Mang, TM);
197  }
198
199
200
201  /// getExplicitSectionGlobal - Targets should implement this method to assign
202  /// a section to globals with an explicit section specfied.  The
203  /// implementation of this method can assume that GV->hasSection() is true.
204  virtual const MCSection *
205  getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
206                           Mangler *Mang, const TargetMachine &TM) const = 0;
207
208  /// getSpecialCasedSectionGlobals - Allow the target to completely override
209  /// section assignment of a global.
210  virtual const MCSection *
211  getSpecialCasedSectionGlobals(const GlobalValue *GV, Mangler *Mang,
212                                SectionKind Kind) const {
213    return 0;
214  }
215
216  /// getExprForDwarfGlobalReference - Return an MCExpr to use for a reference
217  /// to the specified global variable from exception handling information.
218  ///
219  virtual const MCExpr *
220  getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
221                                 MachineModuleInfo *MMI, unsigned Encoding,
222                                 MCStreamer &Streamer) const;
223
224  // getCFIPersonalitySymbol - The symbol that gets passed to .cfi_personality.
225  virtual MCSymbol *
226  getCFIPersonalitySymbol(const GlobalValue *GV, Mangler *Mang,
227                          MachineModuleInfo *MMI) const;
228
229  ///
230  const MCExpr *
231  getExprForDwarfReference(const MCSymbol *Sym, unsigned Encoding,
232                           MCStreamer &Streamer) const;
233
234  virtual unsigned getPersonalityEncoding() const;
235  virtual unsigned getLSDAEncoding() const;
236  virtual unsigned getFDEEncoding(bool CFI) const;
237  virtual unsigned getTTypeEncoding() const;
238
239protected:
240  virtual const MCSection *
241  SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
242                         Mangler *Mang, const TargetMachine &TM) const;
243};
244
245} // end namespace llvm
246
247#endif
248