MCAsmInfo.h revision 1b02acb2a0513b3ec20585196d485ebc3da0ccec 
1//===-- llvm/MC/MCAsmInfo.h - Asm 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 contains a class to be used as the basis for target specific
11// asm writers.  This class primarily takes care of global printing constants,
12// which are used in very similar ways across all targets.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_TARGET_ASM_INFO_H
17#define LLVM_TARGET_ASM_INFO_H
18
19#include "llvm/MC/MCDirectives.h"
20#include <cassert>
21
22namespace llvm {
23  class MCSection;
24  class MCContext;
25
26  /// MCAsmInfo - This class is intended to be used as a base class for asm
27  /// properties and features specific to the target.
28  namespace ExceptionHandling { enum ExceptionsType { None, Dwarf, SjLj }; }
29
30  class MCAsmInfo {
31  protected:
32    //===------------------------------------------------------------------===//
33    // Properties to be set by the target writer, used to configure asm printer.
34    //
35
36    /// HasSubsectionsViaSymbols - True if this target has the MachO
37    /// .subsections_via_symbols directive.
38    bool HasSubsectionsViaSymbols;           // Default is false.
39
40    /// HasMachoZeroFillDirective - True if this is a MachO target that supports
41    /// the macho-specific .zerofill directive for emitting BSS Symbols.
42    bool HasMachoZeroFillDirective;               // Default is false.
43
44    /// HasMachoTBSSDirective - True if this is a MachO target that supports
45    /// the macho-specific .tbss directive for emitting thread local BSS Symbols
46    bool HasMachoTBSSDirective;                 // Default is false.
47
48    /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
49    /// emit a ".reference .constructors_used" or ".reference .destructors_used"
50    /// directive after the a static ctor/dtor list.  This directive is only
51    /// emitted in Static relocation model.
52    bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
53
54    /// MaxInstLength - This is the maximum possible length of an instruction,
55    /// which is needed to compute the size of an inline asm.
56    unsigned MaxInstLength;                  // Defaults to 4.
57
58    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
59    /// relative expressions.
60    const char *PCSymbol;                    // Defaults to "$".
61
62    /// SeparatorChar - This character, if specified, is used to separate
63    /// instructions from each other when on the same line.  This is used to
64    /// measure inline asm instructions.
65    char SeparatorChar;                      // Defaults to ';'
66
67    /// CommentColumn - This indicates the comment num (zero-based) at
68    /// which asm comments should be printed.
69    unsigned CommentColumn;                  // Defaults to 40
70
71    /// CommentString - This indicates the comment character used by the
72    /// assembler.
73    const char *CommentString;               // Defaults to "#"
74
75    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
76    /// onto all global symbols.  This is often used for "_" or ".".
77    const char *GlobalPrefix;                // Defaults to ""
78
79    /// PrivateGlobalPrefix - This prefix is used for globals like constant
80    /// pool entries that are completely private to the .s file and should not
81    /// have names in the .o file.  This is often "." or "L".
82    const char *PrivateGlobalPrefix;         // Defaults to "."
83
84    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
85    /// be passed through the assembler but be removed by the linker.  This
86    /// is "l" on Darwin, currently used for some ObjC metadata.
87    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
88
89    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
90    /// emit before and after an inline assembly statement.
91    const char *InlineAsmStart;              // Defaults to "#APP\n"
92    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
93
94    /// AssemblerDialect - Which dialect of an assembler variant to use.
95    unsigned AssemblerDialect;               // Defaults to 0
96
97    /// AllowQuotesInName - This is true if the assembler allows for complex
98    /// symbol names to be surrounded in quotes.  This defaults to false.
99    bool AllowQuotesInName;
100
101    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
102    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
103    bool AllowNameToStartWithDigit;
104
105    /// AllowPeriodsInName - This is true if the assembler allows periods in
106    /// symbol names.  This defaults to true.
107    bool AllowPeriodsInName;
108
109    //===--- Data Emission Directives -------------------------------------===//
110
111    /// ZeroDirective - this should be set to the directive used to get some
112    /// number of zero bytes emitted to the current section.  Common cases are
113    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
114    /// Data*bitsDirective's will be used to emit zero bytes.
115    const char *ZeroDirective;               // Defaults to "\t.zero\t"
116
117    /// AsciiDirective - This directive allows emission of an ascii string with
118    /// the standard C escape characters embedded into it.
119    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
120
121    /// AscizDirective - If not null, this allows for special handling of
122    /// zero terminated strings on this target.  This is commonly supported as
123    /// ".asciz".  If a target doesn't support this, it can be set to null.
124    const char *AscizDirective;              // Defaults to "\t.asciz\t"
125
126    /// DataDirectives - These directives are used to output some unit of
127    /// integer data to the current section.  If a data directive is set to
128    /// null, smaller data directives will be used to emit the large sizes.
129    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
130    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
131    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
132    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
133
134    /// GPRel32Directive - if non-null, a directive that is used to emit a word
135    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
136    /// on Mips or .gprel32 on Alpha.
137    const char *GPRel32Directive;            // Defaults to NULL.
138
139    /// getDataASDirective - Return the directive that should be used to emit
140    /// data of the specified size to the specified numeric address space.
141    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
142      assert(AS != 0 && "Don't know the directives for default addr space");
143      return 0;
144    }
145
146    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
147    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
148    /// normal ELF syntax (,"a,w") in .section directives.
149    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
150
151    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
152    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
153    /// which doesn't support the '.bss' directive only.
154    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
155
156    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
157    /// style mangling for functions with X86_StdCall/X86_FastCall calling
158    /// convention.
159    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
160
161    //===--- Alignment Information ----------------------------------------===//
162
163    /// AlignDirective - The directive used to emit round up to an alignment
164    /// boundary.
165    ///
166    const char *AlignDirective;              // Defaults to "\t.align\t"
167
168    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
169    /// emits ".align N" directives, where N is the number of bytes to align to.
170    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
171    /// boundary.
172    bool AlignmentIsInBytes;                 // Defaults to true
173
174    /// TextAlignFillValue - If non-zero, this is used to fill the executable
175    /// space created as the result of a alignment directive.
176    unsigned TextAlignFillValue;             // Defaults to 0
177
178    //===--- Global Variable Emission Directives --------------------------===//
179
180    /// GlobalDirective - This is the directive used to declare a global entity.
181    ///
182    const char *GlobalDirective;             // Defaults to NULL.
183
184    /// ExternDirective - This is the directive used to declare external
185    /// globals.
186    ///
187    const char *ExternDirective;             // Defaults to NULL.
188
189    /// HasSetDirective - True if the assembler supports the .set directive.
190    bool HasSetDirective;                    // Defaults to true.
191
192    /// HasLCOMMDirective - This is true if the target supports the .lcomm
193    /// directive.
194    bool HasLCOMMDirective;                  // Defaults to false.
195
196    /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional
197    /// alignment is to be specified in bytes instead of log2(n).
198    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
199
200    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
201    /// directives, this is true for most ELF targets.
202    bool HasDotTypeDotSizeDirective;         // Defaults to true.
203
204    /// HasSingleParameterDotFile - True if the target has a single parameter
205    /// .file directive, this is true for ELF targets.
206    bool HasSingleParameterDotFile;          // Defaults to true.
207
208    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
209    /// directive.
210    bool HasNoDeadStrip;                     // Defaults to false.
211
212    /// WeakRefDirective - This directive, if non-null, is used to declare a
213    /// global as being a weak undefined symbol.
214    const char *WeakRefDirective;            // Defaults to NULL.
215
216    /// WeakDefDirective - This directive, if non-null, is used to declare a
217    /// global as being a weak defined symbol.
218    const char *WeakDefDirective;            // Defaults to NULL.
219
220    /// LinkOnceDirective - This directive, if non-null is used to declare a
221    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
222    const char *LinkOnceDirective;           // Defaults to NULL.
223
224    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
225    /// declare a symbol as having hidden visibility.
226    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
227
228    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
229    /// to declare a symbol as having protected visibility.
230    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
231
232    //===--- Dwarf Emission Directives -----------------------------------===//
233
234    /// HasLEB128 - True if target asm supports leb128 directives.
235    bool HasLEB128;                          // Defaults to false.
236
237    /// hasDotLocAndDotFile - True if target asm supports .loc and .file
238    /// directives for emitting debugging information.
239    bool HasDotLocAndDotFile;                // Defaults to false.
240
241    /// SupportsDebugInformation - True if target supports emission of debugging
242    /// information.
243    bool SupportsDebugInformation;           // Defaults to false.
244
245    /// SupportsExceptionHandling - True if target supports exception handling.
246    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
247
248    /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
249    bool DwarfRequiresFrameSection;          // Defaults to true.
250
251    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
252    /// encode inline subroutine information.
253    bool DwarfUsesInlineInfoSection;         // Defaults to false.
254
255    /// DwarfSectionOffsetDirective - Special section offset directive.
256    const char* DwarfSectionOffsetDirective; // Defaults to NULL
257
258    //===--- CBE Asm Translation Table -----------------------------------===//
259
260    const char *const *AsmTransCBE;          // Defaults to empty
261
262  public:
263    explicit MCAsmInfo();
264    virtual ~MCAsmInfo();
265
266    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
267    static unsigned getSLEB128Size(int Value);
268    static unsigned getULEB128Size(unsigned Value);
269
270    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
271
272    // Data directive accessors.
273    //
274    const char *getData8bitsDirective(unsigned AS = 0) const {
275      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
276    }
277    const char *getData16bitsDirective(unsigned AS = 0) const {
278      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
279    }
280    const char *getData32bitsDirective(unsigned AS = 0) const {
281      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
282    }
283    const char *getData64bitsDirective(unsigned AS = 0) const {
284      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
285    }
286    const char *getGPRel32Directive() const { return GPRel32Directive; }
287
288    /// getNonexecutableStackSection - Targets can implement this method to
289    /// specify a section to switch to if the translation unit doesn't have any
290    /// trampolines that require an executable stack.
291    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
292      return 0;
293    }
294
295    bool usesSunStyleELFSectionSwitchSyntax() const {
296      return SunStyleELFSectionSwitchSyntax;
297    }
298
299    bool usesELFSectionDirectiveForBSS() const {
300      return UsesELFSectionDirectiveForBSS;
301    }
302
303    bool hasMicrosoftFastStdCallMangling() const {
304      return HasMicrosoftFastStdCallMangling;
305    }
306
307    // Accessors.
308    //
309    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
310    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
311    bool hasStaticCtorDtorReferenceInStaticMode() const {
312      return HasStaticCtorDtorReferenceInStaticMode;
313    }
314    unsigned getMaxInstLength() const {
315      return MaxInstLength;
316    }
317    const char *getPCSymbol() const {
318      return PCSymbol;
319    }
320    char getSeparatorChar() const {
321      return SeparatorChar;
322    }
323    unsigned getCommentColumn() const {
324      return CommentColumn;
325    }
326    const char *getCommentString() const {
327      return CommentString;
328    }
329    const char *getGlobalPrefix() const {
330      return GlobalPrefix;
331    }
332    const char *getPrivateGlobalPrefix() const {
333      return PrivateGlobalPrefix;
334    }
335    const char *getLinkerPrivateGlobalPrefix() const {
336      return LinkerPrivateGlobalPrefix;
337    }
338    const char *getInlineAsmStart() const {
339      return InlineAsmStart;
340    }
341    const char *getInlineAsmEnd() const {
342      return InlineAsmEnd;
343    }
344    unsigned getAssemblerDialect() const {
345      return AssemblerDialect;
346    }
347    bool doesAllowQuotesInName() const {
348      return AllowQuotesInName;
349    }
350    bool doesAllowNameToStartWithDigit() const {
351      return AllowNameToStartWithDigit;
352    }
353    bool doesAllowPeriodsInName() const {
354      return AllowPeriodsInName;
355    }
356    const char *getZeroDirective() const {
357      return ZeroDirective;
358    }
359    const char *getAsciiDirective() const {
360      return AsciiDirective;
361    }
362    const char *getAscizDirective() const {
363      return AscizDirective;
364    }
365    const char *getAlignDirective() const {
366      return AlignDirective;
367    }
368    bool getAlignmentIsInBytes() const {
369      return AlignmentIsInBytes;
370    }
371    unsigned getTextAlignFillValue() const {
372      return TextAlignFillValue;
373    }
374    const char *getGlobalDirective() const {
375      return GlobalDirective;
376    }
377    const char *getExternDirective() const {
378      return ExternDirective;
379    }
380    bool hasSetDirective() const { return HasSetDirective; }
381    bool hasLCOMMDirective() const { return HasLCOMMDirective; }
382    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
383    bool getCOMMDirectiveAlignmentIsInBytes() const {
384      return COMMDirectiveAlignmentIsInBytes;
385    }
386    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
387    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
388    const char *getWeakRefDirective() const { return WeakRefDirective; }
389    const char *getWeakDefDirective() const { return WeakDefDirective; }
390    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
391
392    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
393    MCSymbolAttr getProtectedVisibilityAttr() const {
394      return ProtectedVisibilityAttr;
395    }
396    bool hasLEB128() const {
397      return HasLEB128;
398    }
399    bool hasDotLocAndDotFile() const {
400      return HasDotLocAndDotFile;
401    }
402    bool doesSupportDebugInformation() const {
403      return SupportsDebugInformation;
404    }
405    bool doesSupportExceptionHandling() const {
406      return ExceptionsType != ExceptionHandling::None;
407    }
408    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
409      return ExceptionsType;
410    }
411    bool doesDwarfRequireFrameSection() const {
412      return DwarfRequiresFrameSection;
413    }
414    bool doesDwarfUsesInlineInfoSection() const {
415      return DwarfUsesInlineInfoSection;
416    }
417    const char *getDwarfSectionOffsetDirective() const {
418      return DwarfSectionOffsetDirective;
419    }
420    const char *const *getAsmCBE() const {
421      return AsmTransCBE;
422    }
423  };
424}
425
426#endif
427