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1 //===- MCContext.h - Machine Code Context -----------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_MC_MCCONTEXT_H
10 #define LLVM_MC_MCCONTEXT_H
11 
12 #include "llvm/ADT/DenseMap.h"
13 #include "llvm/ADT/Optional.h"
14 #include "llvm/ADT/SetVector.h"
15 #include "llvm/ADT/SmallString.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/ADT/StringMap.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/BinaryFormat/Dwarf.h"
21 #include "llvm/BinaryFormat/ELF.h"
22 #include "llvm/BinaryFormat/XCOFF.h"
23 #include "llvm/MC/MCAsmMacro.h"
24 #include "llvm/MC/MCDwarf.h"
25 #include "llvm/MC/MCSubtargetInfo.h"
26 #include "llvm/MC/MCTargetOptions.h"
27 #include "llvm/MC/SectionKind.h"
28 #include "llvm/Support/Allocator.h"
29 #include "llvm/Support/Compiler.h"
30 #include "llvm/Support/Error.h"
31 #include "llvm/Support/MD5.h"
32 #include "llvm/Support/raw_ostream.h"
33 #include <algorithm>
34 #include <cassert>
35 #include <cstddef>
36 #include <cstdint>
37 #include <map>
38 #include <memory>
39 #include <string>
40 #include <utility>
41 #include <vector>
42 
43 namespace llvm {
44 
45   class CodeViewContext;
46   class MCAsmInfo;
47   class MCLabel;
48   class MCObjectFileInfo;
49   class MCRegisterInfo;
50   class MCSection;
51   class MCSectionCOFF;
52   class MCSectionELF;
53   class MCSectionMachO;
54   class MCSectionWasm;
55   class MCSectionXCOFF;
56   class MCStreamer;
57   class MCSymbol;
58   class MCSymbolELF;
59   class MCSymbolWasm;
60   class MCSymbolXCOFF;
61   class SMLoc;
62   class SourceMgr;
63 
64   /// Context object for machine code objects.  This class owns all of the
65   /// sections that it creates.
66   ///
67   class MCContext {
68   public:
69     using SymbolTable = StringMap<MCSymbol *, BumpPtrAllocator &>;
70 
71   private:
72     /// The SourceMgr for this object, if any.
73     const SourceMgr *SrcMgr;
74 
75     /// The SourceMgr for inline assembly, if any.
76     SourceMgr *InlineSrcMgr;
77 
78     /// The MCAsmInfo for this target.
79     const MCAsmInfo *MAI;
80 
81     /// The MCRegisterInfo for this target.
82     const MCRegisterInfo *MRI;
83 
84     /// The MCObjectFileInfo for this target.
85     const MCObjectFileInfo *MOFI;
86 
87     std::unique_ptr<CodeViewContext> CVContext;
88 
89     /// Allocator object used for creating machine code objects.
90     ///
91     /// We use a bump pointer allocator to avoid the need to track all allocated
92     /// objects.
93     BumpPtrAllocator Allocator;
94 
95     SpecificBumpPtrAllocator<MCSectionCOFF> COFFAllocator;
96     SpecificBumpPtrAllocator<MCSectionELF> ELFAllocator;
97     SpecificBumpPtrAllocator<MCSectionMachO> MachOAllocator;
98     SpecificBumpPtrAllocator<MCSectionWasm> WasmAllocator;
99     SpecificBumpPtrAllocator<MCSectionXCOFF> XCOFFAllocator;
100     SpecificBumpPtrAllocator<MCInst> MCInstAllocator;
101 
102     /// Bindings of names to symbols.
103     SymbolTable Symbols;
104 
105     /// A mapping from a local label number and an instance count to a symbol.
106     /// For example, in the assembly
107     ///     1:
108     ///     2:
109     ///     1:
110     /// We have three labels represented by the pairs (1, 0), (2, 0) and (1, 1)
111     DenseMap<std::pair<unsigned, unsigned>, MCSymbol *> LocalSymbols;
112 
113     /// Keeps tracks of names that were used both for used declared and
114     /// artificial symbols. The value is "true" if the name has been used for a
115     /// non-section symbol (there can be at most one of those, plus an unlimited
116     /// number of section symbols with the same name).
117     StringMap<bool, BumpPtrAllocator &> UsedNames;
118 
119     /// Keeps track of labels that are used in inline assembly.
120     SymbolTable InlineAsmUsedLabelNames;
121 
122     /// The next ID to dole out to an unnamed assembler temporary symbol with
123     /// a given prefix.
124     StringMap<unsigned> NextID;
125 
126     /// Instances of directional local labels.
127     DenseMap<unsigned, MCLabel *> Instances;
128     /// NextInstance() creates the next instance of the directional local label
129     /// for the LocalLabelVal and adds it to the map if needed.
130     unsigned NextInstance(unsigned LocalLabelVal);
131     /// GetInstance() gets the current instance of the directional local label
132     /// for the LocalLabelVal and adds it to the map if needed.
133     unsigned GetInstance(unsigned LocalLabelVal);
134 
135     /// The file name of the log file from the environment variable
136     /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
137     /// directive is used or it is an error.
138     char *SecureLogFile;
139     /// The stream that gets written to for the .secure_log_unique directive.
140     std::unique_ptr<raw_fd_ostream> SecureLog;
141     /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
142     /// catch errors if .secure_log_unique appears twice without
143     /// .secure_log_reset appearing between them.
144     bool SecureLogUsed = false;
145 
146     /// The compilation directory to use for DW_AT_comp_dir.
147     SmallString<128> CompilationDir;
148 
149     /// Prefix replacement map for source file information.
150     std::map<const std::string, const std::string> DebugPrefixMap;
151 
152     /// The main file name if passed in explicitly.
153     std::string MainFileName;
154 
155     /// The dwarf file and directory tables from the dwarf .file directive.
156     /// We now emit a line table for each compile unit. To reduce the prologue
157     /// size of each line table, the files and directories used by each compile
158     /// unit are separated.
159     std::map<unsigned, MCDwarfLineTable> MCDwarfLineTablesCUMap;
160 
161     /// The current dwarf line information from the last dwarf .loc directive.
162     MCDwarfLoc CurrentDwarfLoc;
163     bool DwarfLocSeen = false;
164 
165     /// Generate dwarf debugging info for assembly source files.
166     bool GenDwarfForAssembly = false;
167 
168     /// The current dwarf file number when generate dwarf debugging info for
169     /// assembly source files.
170     unsigned GenDwarfFileNumber = 0;
171 
172     /// Sections for generating the .debug_ranges and .debug_aranges sections.
173     SetVector<MCSection *> SectionsForRanges;
174 
175     /// The information gathered from labels that will have dwarf label
176     /// entries when generating dwarf assembly source files.
177     std::vector<MCGenDwarfLabelEntry> MCGenDwarfLabelEntries;
178 
179     /// The string to embed in the debug information for the compile unit, if
180     /// non-empty.
181     StringRef DwarfDebugFlags;
182 
183     /// The string to embed in as the dwarf AT_producer for the compile unit, if
184     /// non-empty.
185     StringRef DwarfDebugProducer;
186 
187     /// The maximum version of dwarf that we should emit.
188     uint16_t DwarfVersion = 4;
189 
190     /// The format of dwarf that we emit.
191     dwarf::DwarfFormat DwarfFormat = dwarf::DWARF32;
192 
193     /// Honor temporary labels, this is useful for debugging semantic
194     /// differences between temporary and non-temporary labels (primarily on
195     /// Darwin).
196     bool AllowTemporaryLabels = true;
197     bool UseNamesOnTempLabels = false;
198 
199     /// The Compile Unit ID that we are currently processing.
200     unsigned DwarfCompileUnitID = 0;
201 
202     // Sections are differentiated by the quadruple (section_name, group_name,
203     // unique_id, link_to_symbol_name). Sections sharing the same quadruple are
204     // combined into one section.
205     struct ELFSectionKey {
206       std::string SectionName;
207       StringRef GroupName;
208       StringRef LinkedToName;
209       unsigned UniqueID;
210 
ELFSectionKeyELFSectionKey211       ELFSectionKey(StringRef SectionName, StringRef GroupName,
212                     StringRef LinkedToName, unsigned UniqueID)
213           : SectionName(SectionName), GroupName(GroupName),
214             LinkedToName(LinkedToName), UniqueID(UniqueID) {}
215 
216       bool operator<(const ELFSectionKey &Other) const {
217         if (SectionName != Other.SectionName)
218           return SectionName < Other.SectionName;
219         if (GroupName != Other.GroupName)
220           return GroupName < Other.GroupName;
221         if (int O = LinkedToName.compare(Other.LinkedToName))
222           return O < 0;
223         return UniqueID < Other.UniqueID;
224       }
225     };
226 
227     struct COFFSectionKey {
228       std::string SectionName;
229       StringRef GroupName;
230       int SelectionKey;
231       unsigned UniqueID;
232 
COFFSectionKeyCOFFSectionKey233       COFFSectionKey(StringRef SectionName, StringRef GroupName,
234                      int SelectionKey, unsigned UniqueID)
235           : SectionName(SectionName), GroupName(GroupName),
236             SelectionKey(SelectionKey), UniqueID(UniqueID) {}
237 
238       bool operator<(const COFFSectionKey &Other) const {
239         if (SectionName != Other.SectionName)
240           return SectionName < Other.SectionName;
241         if (GroupName != Other.GroupName)
242           return GroupName < Other.GroupName;
243         if (SelectionKey != Other.SelectionKey)
244           return SelectionKey < Other.SelectionKey;
245         return UniqueID < Other.UniqueID;
246       }
247     };
248 
249     struct WasmSectionKey {
250       std::string SectionName;
251       StringRef GroupName;
252       unsigned UniqueID;
253 
WasmSectionKeyWasmSectionKey254       WasmSectionKey(StringRef SectionName, StringRef GroupName,
255                      unsigned UniqueID)
256           : SectionName(SectionName), GroupName(GroupName), UniqueID(UniqueID) {
257       }
258 
259       bool operator<(const WasmSectionKey &Other) const {
260         if (SectionName != Other.SectionName)
261           return SectionName < Other.SectionName;
262         if (GroupName != Other.GroupName)
263           return GroupName < Other.GroupName;
264         return UniqueID < Other.UniqueID;
265       }
266     };
267 
268     struct XCOFFSectionKey {
269       std::string SectionName;
270       XCOFF::StorageMappingClass MappingClass;
271 
XCOFFSectionKeyXCOFFSectionKey272       XCOFFSectionKey(StringRef SectionName,
273                       XCOFF::StorageMappingClass MappingClass)
274           : SectionName(SectionName), MappingClass(MappingClass) {}
275 
276       bool operator<(const XCOFFSectionKey &Other) const {
277         return std::tie(SectionName, MappingClass) <
278                std::tie(Other.SectionName, Other.MappingClass);
279       }
280     };
281 
282     StringMap<MCSectionMachO *> MachOUniquingMap;
283     std::map<ELFSectionKey, MCSectionELF *> ELFUniquingMap;
284     std::map<COFFSectionKey, MCSectionCOFF *> COFFUniquingMap;
285     std::map<WasmSectionKey, MCSectionWasm *> WasmUniquingMap;
286     std::map<XCOFFSectionKey, MCSectionXCOFF *> XCOFFUniquingMap;
287     StringMap<bool> RelSecNames;
288 
289     SpecificBumpPtrAllocator<MCSubtargetInfo> MCSubtargetAllocator;
290 
291     /// Do automatic reset in destructor
292     bool AutoReset;
293 
294     MCTargetOptions const *TargetOptions;
295 
296     bool HadError = false;
297 
298     MCSymbol *createSymbolImpl(const StringMapEntry<bool> *Name,
299                                bool CanBeUnnamed);
300     MCSymbol *createSymbol(StringRef Name, bool AlwaysAddSuffix,
301                            bool IsTemporary);
302 
303     MCSymbol *getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
304                                                 unsigned Instance);
305 
306     MCSectionELF *createELFSectionImpl(StringRef Section, unsigned Type,
307                                        unsigned Flags, SectionKind K,
308                                        unsigned EntrySize,
309                                        const MCSymbolELF *Group,
310                                        unsigned UniqueID,
311                                        const MCSymbolELF *LinkedToSym);
312 
313     MCSymbolXCOFF *createXCOFFSymbolImpl(const StringMapEntry<bool> *Name,
314                                          bool IsTemporary);
315 
316     /// Map of currently defined macros.
317     StringMap<MCAsmMacro> MacroMap;
318 
319     struct ELFEntrySizeKey {
320       std::string SectionName;
321       unsigned Flags;
322       unsigned EntrySize;
323 
ELFEntrySizeKeyELFEntrySizeKey324       ELFEntrySizeKey(StringRef SectionName, unsigned Flags, unsigned EntrySize)
325           : SectionName(SectionName), Flags(Flags), EntrySize(EntrySize) {}
326 
327       bool operator<(const ELFEntrySizeKey &Other) const {
328         if (SectionName != Other.SectionName)
329           return SectionName < Other.SectionName;
330         if ((Flags & ELF::SHF_STRINGS) != (Other.Flags & ELF::SHF_STRINGS))
331           return Other.Flags & ELF::SHF_STRINGS;
332         return EntrySize < Other.EntrySize;
333       }
334     };
335 
336     // Symbols must be assigned to a section with a compatible entry
337     // size. This map is used to assign unique IDs to sections to
338     // distinguish between sections with identical names but incompatible entry
339     // sizes. This can occur when a symbol is explicitly assigned to a
340     // section, e.g. via __attribute__((section("myname"))).
341     std::map<ELFEntrySizeKey, unsigned> ELFEntrySizeMap;
342 
343     // This set is used to record the generic mergeable section names seen.
344     // These are sections that are created as mergeable e.g. .debug_str. We need
345     // to avoid assigning non-mergeable symbols to these sections. It is used
346     // to prevent non-mergeable symbols being explicitly assigned  to mergeable
347     // sections (e.g. via _attribute_((section("myname")))).
348     DenseSet<StringRef> ELFSeenGenericMergeableSections;
349 
350   public:
351     explicit MCContext(const MCAsmInfo *MAI, const MCRegisterInfo *MRI,
352                        const MCObjectFileInfo *MOFI,
353                        const SourceMgr *Mgr = nullptr,
354                        MCTargetOptions const *TargetOpts = nullptr,
355                        bool DoAutoReset = true);
356     MCContext(const MCContext &) = delete;
357     MCContext &operator=(const MCContext &) = delete;
358     ~MCContext();
359 
getSourceManager()360     const SourceMgr *getSourceManager() const { return SrcMgr; }
361 
setInlineSourceManager(SourceMgr * SM)362     void setInlineSourceManager(SourceMgr *SM) { InlineSrcMgr = SM; }
363 
getAsmInfo()364     const MCAsmInfo *getAsmInfo() const { return MAI; }
365 
getRegisterInfo()366     const MCRegisterInfo *getRegisterInfo() const { return MRI; }
367 
getObjectFileInfo()368     const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; }
369 
370     CodeViewContext &getCVContext();
371 
setAllowTemporaryLabels(bool Value)372     void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
setUseNamesOnTempLabels(bool Value)373     void setUseNamesOnTempLabels(bool Value) { UseNamesOnTempLabels = Value; }
374 
375     /// \name Module Lifetime Management
376     /// @{
377 
378     /// reset - return object to right after construction state to prepare
379     /// to process a new module
380     void reset();
381 
382     /// @}
383 
384     /// \name McInst Management
385 
386     /// Create and return a new MC instruction.
387     MCInst *createMCInst();
388 
389     /// \name Symbol Management
390     /// @{
391 
392     /// Create and return a new linker temporary symbol with a unique but
393     /// unspecified name.
394     MCSymbol *createLinkerPrivateTempSymbol();
395 
396     /// Create and return a new assembler temporary symbol with a unique but
397     /// unspecified name.
398     MCSymbol *createTempSymbol(bool CanBeUnnamed = true);
399 
400     MCSymbol *createTempSymbol(const Twine &Name, bool AlwaysAddSuffix,
401                                bool CanBeUnnamed = true);
402 
403     /// Create the definition of a directional local symbol for numbered label
404     /// (used for "1:" definitions).
405     MCSymbol *createDirectionalLocalSymbol(unsigned LocalLabelVal);
406 
407     /// Create and return a directional local symbol for numbered label (used
408     /// for "1b" or 1f" references).
409     MCSymbol *getDirectionalLocalSymbol(unsigned LocalLabelVal, bool Before);
410 
411     /// Lookup the symbol inside with the specified \p Name.  If it exists,
412     /// return it.  If not, create a forward reference and return it.
413     ///
414     /// \param Name - The symbol name, which must be unique across all symbols.
415     MCSymbol *getOrCreateSymbol(const Twine &Name);
416 
417     /// Gets a symbol that will be defined to the final stack offset of a local
418     /// variable after codegen.
419     ///
420     /// \param Idx - The index of a local variable passed to \@llvm.localescape.
421     MCSymbol *getOrCreateFrameAllocSymbol(StringRef FuncName, unsigned Idx);
422 
423     MCSymbol *getOrCreateParentFrameOffsetSymbol(StringRef FuncName);
424 
425     MCSymbol *getOrCreateLSDASymbol(StringRef FuncName);
426 
427     /// Get the symbol for \p Name, or null.
428     MCSymbol *lookupSymbol(const Twine &Name) const;
429 
430     /// Set value for a symbol.
431     void setSymbolValue(MCStreamer &Streamer, StringRef Sym, uint64_t Val);
432 
433     /// getSymbols - Get a reference for the symbol table for clients that
434     /// want to, for example, iterate over all symbols. 'const' because we
435     /// still want any modifications to the table itself to use the MCContext
436     /// APIs.
getSymbols()437     const SymbolTable &getSymbols() const { return Symbols; }
438 
439     /// isInlineAsmLabel - Return true if the name is a label referenced in
440     /// inline assembly.
getInlineAsmLabel(StringRef Name)441     MCSymbol *getInlineAsmLabel(StringRef Name) const {
442       return InlineAsmUsedLabelNames.lookup(Name);
443     }
444 
445     /// registerInlineAsmLabel - Records that the name is a label referenced in
446     /// inline assembly.
447     void registerInlineAsmLabel(MCSymbol *Sym);
448 
449     /// @}
450 
451     /// \name Section Management
452     /// @{
453 
454     enum : unsigned {
455       /// Pass this value as the UniqueID during section creation to get the
456       /// generic section with the given name and characteristics. The usual
457       /// sections such as .text use this ID.
458       GenericSectionID = ~0U
459     };
460 
461     /// Return the MCSection for the specified mach-o section.  This requires
462     /// the operands to be valid.
463     MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section,
464                                     unsigned TypeAndAttributes,
465                                     unsigned Reserved2, SectionKind K,
466                                     const char *BeginSymName = nullptr);
467 
468     MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section,
469                                     unsigned TypeAndAttributes, SectionKind K,
470                                     const char *BeginSymName = nullptr) {
471       return getMachOSection(Segment, Section, TypeAndAttributes, 0, K,
472                              BeginSymName);
473     }
474 
getELFSection(const Twine & Section,unsigned Type,unsigned Flags)475     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
476                                 unsigned Flags) {
477       return getELFSection(Section, Type, Flags, 0, "");
478     }
479 
getELFSection(const Twine & Section,unsigned Type,unsigned Flags,unsigned EntrySize,const Twine & Group)480     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
481                                 unsigned Flags, unsigned EntrySize,
482                                 const Twine &Group) {
483       return getELFSection(Section, Type, Flags, EntrySize, Group,
484                            MCSection::NonUniqueID, nullptr);
485     }
486 
487     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
488                                 unsigned Flags, unsigned EntrySize,
489                                 const Twine &Group, unsigned UniqueID,
490                                 const MCSymbolELF *LinkedToSym);
491 
492     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
493                                 unsigned Flags, unsigned EntrySize,
494                                 const MCSymbolELF *Group, unsigned UniqueID,
495                                 const MCSymbolELF *LinkedToSym);
496 
497     /// Get a section with the provided group identifier. This section is
498     /// named by concatenating \p Prefix with '.' then \p Suffix. The \p Type
499     /// describes the type of the section and \p Flags are used to further
500     /// configure this named section.
501     MCSectionELF *getELFNamedSection(const Twine &Prefix, const Twine &Suffix,
502                                      unsigned Type, unsigned Flags,
503                                      unsigned EntrySize = 0);
504 
505     MCSectionELF *createELFRelSection(const Twine &Name, unsigned Type,
506                                       unsigned Flags, unsigned EntrySize,
507                                       const MCSymbolELF *Group,
508                                       const MCSectionELF *RelInfoSection);
509 
510     void renameELFSection(MCSectionELF *Section, StringRef Name);
511 
512     MCSectionELF *createELFGroupSection(const MCSymbolELF *Group);
513 
514     void recordELFMergeableSectionInfo(StringRef SectionName, unsigned Flags,
515                                        unsigned UniqueID, unsigned EntrySize);
516 
517     bool isELFImplicitMergeableSectionNamePrefix(StringRef Name);
518 
519     bool isELFGenericMergeableSection(StringRef Name);
520 
521     Optional<unsigned> getELFUniqueIDForEntsize(StringRef SectionName,
522                                                 unsigned Flags,
523                                                 unsigned EntrySize);
524 
525     MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics,
526                                   SectionKind Kind, StringRef COMDATSymName,
527                                   int Selection,
528                                   unsigned UniqueID = GenericSectionID,
529                                   const char *BeginSymName = nullptr);
530 
531     MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics,
532                                   SectionKind Kind,
533                                   const char *BeginSymName = nullptr);
534 
535     /// Gets or creates a section equivalent to Sec that is associated with the
536     /// section containing KeySym. For example, to create a debug info section
537     /// associated with an inline function, pass the normal debug info section
538     /// as Sec and the function symbol as KeySym.
539     MCSectionCOFF *
540     getAssociativeCOFFSection(MCSectionCOFF *Sec, const MCSymbol *KeySym,
541                               unsigned UniqueID = GenericSectionID);
542 
getWasmSection(const Twine & Section,SectionKind K)543     MCSectionWasm *getWasmSection(const Twine &Section, SectionKind K) {
544       return getWasmSection(Section, K, nullptr);
545     }
546 
getWasmSection(const Twine & Section,SectionKind K,const char * BeginSymName)547     MCSectionWasm *getWasmSection(const Twine &Section, SectionKind K,
548                                   const char *BeginSymName) {
549       return getWasmSection(Section, K, "", ~0, BeginSymName);
550     }
551 
getWasmSection(const Twine & Section,SectionKind K,const Twine & Group,unsigned UniqueID)552     MCSectionWasm *getWasmSection(const Twine &Section, SectionKind K,
553                                   const Twine &Group, unsigned UniqueID) {
554       return getWasmSection(Section, K, Group, UniqueID, nullptr);
555     }
556 
557     MCSectionWasm *getWasmSection(const Twine &Section, SectionKind K,
558                                   const Twine &Group, unsigned UniqueID,
559                                   const char *BeginSymName);
560 
561     MCSectionWasm *getWasmSection(const Twine &Section, SectionKind K,
562                                   const MCSymbolWasm *Group, unsigned UniqueID,
563                                   const char *BeginSymName);
564 
565     MCSectionXCOFF *getXCOFFSection(StringRef Section,
566                                     XCOFF::StorageMappingClass MappingClass,
567                                     XCOFF::SymbolType CSectType, SectionKind K,
568                                     bool MultiSymbolsAllowed = false,
569                                     const char *BeginSymName = nullptr);
570 
571     // Create and save a copy of STI and return a reference to the copy.
572     MCSubtargetInfo &getSubtargetCopy(const MCSubtargetInfo &STI);
573 
574     /// @}
575 
576     /// \name Dwarf Management
577     /// @{
578 
579     /// Get the compilation directory for DW_AT_comp_dir
580     /// The compilation directory should be set with \c setCompilationDir before
581     /// calling this function. If it is unset, an empty string will be returned.
getCompilationDir()582     StringRef getCompilationDir() const { return CompilationDir; }
583 
584     /// Set the compilation directory for DW_AT_comp_dir
setCompilationDir(StringRef S)585     void setCompilationDir(StringRef S) { CompilationDir = S.str(); }
586 
587     /// Add an entry to the debug prefix map.
588     void addDebugPrefixMapEntry(const std::string &From, const std::string &To);
589 
590     // Remaps all debug directory paths in-place as per the debug prefix map.
591     void RemapDebugPaths();
592 
593     /// Get the main file name for use in error messages and debug
594     /// info. This can be set to ensure we've got the correct file name
595     /// after preprocessing or for -save-temps.
getMainFileName()596     const std::string &getMainFileName() const { return MainFileName; }
597 
598     /// Set the main file name and override the default.
setMainFileName(StringRef S)599     void setMainFileName(StringRef S) { MainFileName = std::string(S); }
600 
601     /// Creates an entry in the dwarf file and directory tables.
602     Expected<unsigned> getDwarfFile(StringRef Directory, StringRef FileName,
603                                     unsigned FileNumber,
604                                     Optional<MD5::MD5Result> Checksum,
605                                     Optional<StringRef> Source, unsigned CUID);
606 
607     bool isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID = 0);
608 
getMCDwarfLineTables()609     const std::map<unsigned, MCDwarfLineTable> &getMCDwarfLineTables() const {
610       return MCDwarfLineTablesCUMap;
611     }
612 
getMCDwarfLineTable(unsigned CUID)613     MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) {
614       return MCDwarfLineTablesCUMap[CUID];
615     }
616 
getMCDwarfLineTable(unsigned CUID)617     const MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) const {
618       auto I = MCDwarfLineTablesCUMap.find(CUID);
619       assert(I != MCDwarfLineTablesCUMap.end());
620       return I->second;
621     }
622 
623     const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles(unsigned CUID = 0) {
624       return getMCDwarfLineTable(CUID).getMCDwarfFiles();
625     }
626 
627     const SmallVectorImpl<std::string> &getMCDwarfDirs(unsigned CUID = 0) {
628       return getMCDwarfLineTable(CUID).getMCDwarfDirs();
629     }
630 
getDwarfCompileUnitID()631     unsigned getDwarfCompileUnitID() { return DwarfCompileUnitID; }
632 
setDwarfCompileUnitID(unsigned CUIndex)633     void setDwarfCompileUnitID(unsigned CUIndex) {
634       DwarfCompileUnitID = CUIndex;
635     }
636 
637     /// Specifies the "root" file and directory of the compilation unit.
638     /// These are "file 0" and "directory 0" in DWARF v5.
setMCLineTableRootFile(unsigned CUID,StringRef CompilationDir,StringRef Filename,Optional<MD5::MD5Result> Checksum,Optional<StringRef> Source)639     void setMCLineTableRootFile(unsigned CUID, StringRef CompilationDir,
640                                 StringRef Filename,
641                                 Optional<MD5::MD5Result> Checksum,
642                                 Optional<StringRef> Source) {
643       getMCDwarfLineTable(CUID).setRootFile(CompilationDir, Filename, Checksum,
644                                             Source);
645     }
646 
647     /// Reports whether MD5 checksum usage is consistent (all-or-none).
isDwarfMD5UsageConsistent(unsigned CUID)648     bool isDwarfMD5UsageConsistent(unsigned CUID) const {
649       return getMCDwarfLineTable(CUID).isMD5UsageConsistent();
650     }
651 
652     /// Saves the information from the currently parsed dwarf .loc directive
653     /// and sets DwarfLocSeen.  When the next instruction is assembled an entry
654     /// in the line number table with this information and the address of the
655     /// instruction will be created.
setCurrentDwarfLoc(unsigned FileNum,unsigned Line,unsigned Column,unsigned Flags,unsigned Isa,unsigned Discriminator)656     void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
657                             unsigned Flags, unsigned Isa,
658                             unsigned Discriminator) {
659       CurrentDwarfLoc.setFileNum(FileNum);
660       CurrentDwarfLoc.setLine(Line);
661       CurrentDwarfLoc.setColumn(Column);
662       CurrentDwarfLoc.setFlags(Flags);
663       CurrentDwarfLoc.setIsa(Isa);
664       CurrentDwarfLoc.setDiscriminator(Discriminator);
665       DwarfLocSeen = true;
666     }
667 
clearDwarfLocSeen()668     void clearDwarfLocSeen() { DwarfLocSeen = false; }
669 
getDwarfLocSeen()670     bool getDwarfLocSeen() { return DwarfLocSeen; }
getCurrentDwarfLoc()671     const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
672 
getGenDwarfForAssembly()673     bool getGenDwarfForAssembly() { return GenDwarfForAssembly; }
setGenDwarfForAssembly(bool Value)674     void setGenDwarfForAssembly(bool Value) { GenDwarfForAssembly = Value; }
getGenDwarfFileNumber()675     unsigned getGenDwarfFileNumber() { return GenDwarfFileNumber; }
676 
setGenDwarfFileNumber(unsigned FileNumber)677     void setGenDwarfFileNumber(unsigned FileNumber) {
678       GenDwarfFileNumber = FileNumber;
679     }
680 
681     /// Specifies information about the "root file" for assembler clients
682     /// (e.g., llvm-mc). Assumes compilation dir etc. have been set up.
683     void setGenDwarfRootFile(StringRef FileName, StringRef Buffer);
684 
getGenDwarfSectionSyms()685     const SetVector<MCSection *> &getGenDwarfSectionSyms() {
686       return SectionsForRanges;
687     }
688 
addGenDwarfSection(MCSection * Sec)689     bool addGenDwarfSection(MCSection *Sec) {
690       return SectionsForRanges.insert(Sec);
691     }
692 
693     void finalizeDwarfSections(MCStreamer &MCOS);
694 
getMCGenDwarfLabelEntries()695     const std::vector<MCGenDwarfLabelEntry> &getMCGenDwarfLabelEntries() const {
696       return MCGenDwarfLabelEntries;
697     }
698 
addMCGenDwarfLabelEntry(const MCGenDwarfLabelEntry & E)699     void addMCGenDwarfLabelEntry(const MCGenDwarfLabelEntry &E) {
700       MCGenDwarfLabelEntries.push_back(E);
701     }
702 
setDwarfDebugFlags(StringRef S)703     void setDwarfDebugFlags(StringRef S) { DwarfDebugFlags = S; }
getDwarfDebugFlags()704     StringRef getDwarfDebugFlags() { return DwarfDebugFlags; }
705 
setDwarfDebugProducer(StringRef S)706     void setDwarfDebugProducer(StringRef S) { DwarfDebugProducer = S; }
getDwarfDebugProducer()707     StringRef getDwarfDebugProducer() { return DwarfDebugProducer; }
708 
setDwarfFormat(dwarf::DwarfFormat f)709     void setDwarfFormat(dwarf::DwarfFormat f) { DwarfFormat = f; }
getDwarfFormat()710     dwarf::DwarfFormat getDwarfFormat() const { return DwarfFormat; }
711 
setDwarfVersion(uint16_t v)712     void setDwarfVersion(uint16_t v) { DwarfVersion = v; }
getDwarfVersion()713     uint16_t getDwarfVersion() const { return DwarfVersion; }
714 
715     /// @}
716 
getSecureLogFile()717     char *getSecureLogFile() { return SecureLogFile; }
getSecureLog()718     raw_fd_ostream *getSecureLog() { return SecureLog.get(); }
719 
setSecureLog(std::unique_ptr<raw_fd_ostream> Value)720     void setSecureLog(std::unique_ptr<raw_fd_ostream> Value) {
721       SecureLog = std::move(Value);
722     }
723 
getSecureLogUsed()724     bool getSecureLogUsed() { return SecureLogUsed; }
setSecureLogUsed(bool Value)725     void setSecureLogUsed(bool Value) { SecureLogUsed = Value; }
726 
727     void *allocate(unsigned Size, unsigned Align = 8) {
728       return Allocator.Allocate(Size, Align);
729     }
730 
deallocate(void * Ptr)731     void deallocate(void *Ptr) {}
732 
hadError()733     bool hadError() { return HadError; }
734     void reportError(SMLoc L, const Twine &Msg);
735     void reportWarning(SMLoc L, const Twine &Msg);
736     // Unrecoverable error has occurred. Display the best diagnostic we can
737     // and bail via exit(1). For now, most MC backend errors are unrecoverable.
738     // FIXME: We should really do something about that.
739     LLVM_ATTRIBUTE_NORETURN void reportFatalError(SMLoc L,
740                                                   const Twine &Msg);
741 
lookupMacro(StringRef Name)742     const MCAsmMacro *lookupMacro(StringRef Name) {
743       StringMap<MCAsmMacro>::iterator I = MacroMap.find(Name);
744       return (I == MacroMap.end()) ? nullptr : &I->getValue();
745     }
746 
defineMacro(StringRef Name,MCAsmMacro Macro)747     void defineMacro(StringRef Name, MCAsmMacro Macro) {
748       MacroMap.insert(std::make_pair(Name, std::move(Macro)));
749     }
750 
undefineMacro(StringRef Name)751     void undefineMacro(StringRef Name) { MacroMap.erase(Name); }
752   };
753 
754 } // end namespace llvm
755 
756 // operator new and delete aren't allowed inside namespaces.
757 // The throw specifications are mandated by the standard.
758 /// Placement new for using the MCContext's allocator.
759 ///
760 /// This placement form of operator new uses the MCContext's allocator for
761 /// obtaining memory. It is a non-throwing new, which means that it returns
762 /// null on error. (If that is what the allocator does. The current does, so if
763 /// this ever changes, this operator will have to be changed, too.)
764 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
765 /// \code
766 /// // Default alignment (8)
767 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
768 /// // Specific alignment
769 /// IntegerLiteral *Ex2 = new (Context, 4) IntegerLiteral(arguments);
770 /// \endcode
771 /// Please note that you cannot use delete on the pointer; it must be
772 /// deallocated using an explicit destructor call followed by
773 /// \c Context.Deallocate(Ptr).
774 ///
775 /// \param Bytes The number of bytes to allocate. Calculated by the compiler.
776 /// \param C The MCContext that provides the allocator.
777 /// \param Alignment The alignment of the allocated memory (if the underlying
778 ///                  allocator supports it).
779 /// \return The allocated memory. Could be NULL.
780 inline void *operator new(size_t Bytes, llvm::MCContext &C,
781                           size_t Alignment = 8) noexcept {
782   return C.allocate(Bytes, Alignment);
783 }
784 /// Placement delete companion to the new above.
785 ///
786 /// This operator is just a companion to the new above. There is no way of
787 /// invoking it directly; see the new operator for more details. This operator
788 /// is called implicitly by the compiler if a placement new expression using
789 /// the MCContext throws in the object constructor.
delete(void * Ptr,llvm::MCContext & C,size_t)790 inline void operator delete(void *Ptr, llvm::MCContext &C, size_t) noexcept {
791   C.deallocate(Ptr);
792 }
793 
794 /// This placement form of operator new[] uses the MCContext's allocator for
795 /// obtaining memory. It is a non-throwing new[], which means that it returns
796 /// null on error.
797 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
798 /// \code
799 /// // Default alignment (8)
800 /// char *data = new (Context) char[10];
801 /// // Specific alignment
802 /// char *data = new (Context, 4) char[10];
803 /// \endcode
804 /// Please note that you cannot use delete on the pointer; it must be
805 /// deallocated using an explicit destructor call followed by
806 /// \c Context.Deallocate(Ptr).
807 ///
808 /// \param Bytes The number of bytes to allocate. Calculated by the compiler.
809 /// \param C The MCContext that provides the allocator.
810 /// \param Alignment The alignment of the allocated memory (if the underlying
811 ///                  allocator supports it).
812 /// \return The allocated memory. Could be NULL.
813 inline void *operator new[](size_t Bytes, llvm::MCContext &C,
814                             size_t Alignment = 8) noexcept {
815   return C.allocate(Bytes, Alignment);
816 }
817 
818 /// Placement delete[] companion to the new[] above.
819 ///
820 /// This operator is just a companion to the new[] above. There is no way of
821 /// invoking it directly; see the new[] operator for more details. This operator
822 /// is called implicitly by the compiler if a placement new[] expression using
823 /// the MCContext throws in the object constructor.
824 inline void operator delete[](void *Ptr, llvm::MCContext &C) noexcept {
825   C.deallocate(Ptr);
826 }
827 
828 #endif // LLVM_MC_MCCONTEXT_H
829