MCAsmInfo.h revision 5c0556341e29246e697c73844a5f9b1e14474715 
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    /// LabelSuffix - This is appended to emitted labels.
76    const char *LabelSuffix;                 // Defaults to ":"
77
78    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
79    /// onto all global symbols.  This is often used for "_" or ".".
80    const char *GlobalPrefix;                // Defaults to ""
81
82    /// PrivateGlobalPrefix - This prefix is used for globals like constant
83    /// pool entries that are completely private to the .s file and should not
84    /// have names in the .o file.  This is often "." or "L".
85    const char *PrivateGlobalPrefix;         // Defaults to "."
86
87    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
88    /// be passed through the assembler but be removed by the linker.  This
89    /// is "l" on Darwin, currently used for some ObjC metadata.
90    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
91
92    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
93    /// emit before and after an inline assembly statement.
94    const char *InlineAsmStart;              // Defaults to "#APP\n"
95    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
96
97    /// AssemblerDialect - Which dialect of an assembler variant to use.
98    unsigned AssemblerDialect;               // Defaults to 0
99
100    /// AllowQuotesInName - This is true if the assembler allows for complex
101    /// symbol names to be surrounded in quotes.  This defaults to false.
102    bool AllowQuotesInName;
103
104    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
105    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
106    bool AllowNameToStartWithDigit;
107
108    /// AllowPeriodsInName - This is true if the assembler allows periods in
109    /// symbol names.  This defaults to true.
110    bool AllowPeriodsInName;
111
112    //===--- Data Emission Directives -------------------------------------===//
113
114    /// ZeroDirective - this should be set to the directive used to get some
115    /// number of zero bytes emitted to the current section.  Common cases are
116    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
117    /// Data*bitsDirective's will be used to emit zero bytes.
118    const char *ZeroDirective;               // Defaults to "\t.zero\t"
119
120    /// AsciiDirective - This directive allows emission of an ascii string with
121    /// the standard C escape characters embedded into it.
122    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
123
124    /// AscizDirective - If not null, this allows for special handling of
125    /// zero terminated strings on this target.  This is commonly supported as
126    /// ".asciz".  If a target doesn't support this, it can be set to null.
127    const char *AscizDirective;              // Defaults to "\t.asciz\t"
128
129    /// DataDirectives - These directives are used to output some unit of
130    /// integer data to the current section.  If a data directive is set to
131    /// null, smaller data directives will be used to emit the large sizes.
132    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
133    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
134    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
135    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
136
137    /// GPRel32Directive - if non-null, a directive that is used to emit a word
138    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
139    /// on Mips or .gprel32 on Alpha.
140    const char *GPRel32Directive;            // Defaults to NULL.
141
142    /// getDataASDirective - Return the directive that should be used to emit
143    /// data of the specified size to the specified numeric address space.
144    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
145      assert(AS != 0 && "Don't know the directives for default addr space");
146      return 0;
147    }
148
149    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
150    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
151    /// normal ELF syntax (,"a,w") in .section directives.
152    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
153
154    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
155    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
156    /// which doesn't support the '.bss' directive only.
157    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
158
159    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
160    /// style mangling for functions with X86_StdCall/X86_FastCall calling
161    /// convention.
162    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
163
164    //===--- Alignment Information ----------------------------------------===//
165
166    /// AlignDirective - The directive used to emit round up to an alignment
167    /// boundary.
168    ///
169    const char *AlignDirective;              // Defaults to "\t.align\t"
170
171    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
172    /// emits ".align N" directives, where N is the number of bytes to align to.
173    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
174    /// boundary.
175    bool AlignmentIsInBytes;                 // Defaults to true
176
177    /// TextAlignFillValue - If non-zero, this is used to fill the executable
178    /// space created as the result of a alignment directive.
179    unsigned TextAlignFillValue;             // Defaults to 0
180
181    //===--- Global Variable Emission Directives --------------------------===//
182
183    /// GlobalDirective - This is the directive used to declare a global entity.
184    ///
185    const char *GlobalDirective;             // Defaults to NULL.
186
187    /// ExternDirective - This is the directive used to declare external
188    /// globals.
189    ///
190    const char *ExternDirective;             // Defaults to NULL.
191
192    /// HasSetDirective - True if the assembler supports the .set directive.
193    bool HasSetDirective;                    // Defaults to true.
194
195    /// HasLCOMMDirective - This is true if the target supports the .lcomm
196    /// directive.
197    bool HasLCOMMDirective;                  // Defaults to false.
198
199    /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional
200    /// alignment is to be specified in bytes instead of log2(n).
201    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
202
203    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
204    /// directives, this is true for most ELF targets.
205    bool HasDotTypeDotSizeDirective;         // Defaults to true.
206
207    /// HasSingleParameterDotFile - True if the target has a single parameter
208    /// .file directive, this is true for ELF targets.
209    bool HasSingleParameterDotFile;          // Defaults to true.
210
211    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
212    /// directive.
213    bool HasNoDeadStrip;                     // Defaults to false.
214
215    /// WeakRefDirective - This directive, if non-null, is used to declare a
216    /// global as being a weak undefined symbol.
217    const char *WeakRefDirective;            // Defaults to NULL.
218
219    /// WeakDefDirective - This directive, if non-null, is used to declare a
220    /// global as being a weak defined symbol.
221    const char *WeakDefDirective;            // Defaults to NULL.
222
223    /// LinkOnceDirective - This directive, if non-null is used to declare a
224    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
225    const char *LinkOnceDirective;           // Defaults to NULL.
226
227    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
228    /// declare a symbol as having hidden visibility.
229    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
230
231    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
232    /// to declare a symbol as having protected visibility.
233    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
234
235    //===--- Dwarf Emission Directives -----------------------------------===//
236
237    /// HasLEB128 - True if target asm supports leb128 directives.
238    bool HasLEB128;                          // Defaults to false.
239
240    /// SupportsDebugInformation - True if target supports emission of debugging
241    /// information.
242    bool SupportsDebugInformation;           // Defaults to false.
243
244    /// SupportsExceptionHandling - True if target supports exception handling.
245    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
246
247    /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
248    bool DwarfRequiresFrameSection;          // Defaults to true.
249
250    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
251    /// encode inline subroutine information.
252    bool DwarfUsesInlineInfoSection;         // Defaults to false.
253
254    /// DwarfSectionOffsetDirective - Special section offset directive.
255    const char* DwarfSectionOffsetDirective; // Defaults to NULL
256
257    /// DwarfUsesAbsoluteLabelForStmtList - True if DW_AT_stmt_list needs
258    /// absolute label instead of offset.
259    bool DwarfUsesAbsoluteLabelForStmtList;  // Defaults to true;
260
261    // DwarfUsesLabelOffsetDifference - True if Dwarf2 output can
262    // use EmitLabelOffsetDifference.
263    bool DwarfUsesLabelOffsetForRanges;
264
265    //===--- CBE Asm Translation Table -----------------------------------===//
266
267    const char *const *AsmTransCBE;          // Defaults to empty
268
269  public:
270    explicit MCAsmInfo();
271    virtual ~MCAsmInfo();
272
273    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
274    static unsigned getSLEB128Size(int Value);
275    static unsigned getULEB128Size(unsigned Value);
276
277    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
278
279    // Data directive accessors.
280    //
281    const char *getData8bitsDirective(unsigned AS = 0) const {
282      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
283    }
284    const char *getData16bitsDirective(unsigned AS = 0) const {
285      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
286    }
287    const char *getData32bitsDirective(unsigned AS = 0) const {
288      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
289    }
290    const char *getData64bitsDirective(unsigned AS = 0) const {
291      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
292    }
293    const char *getGPRel32Directive() const { return GPRel32Directive; }
294
295    /// getNonexecutableStackSection - Targets can implement this method to
296    /// specify a section to switch to if the translation unit doesn't have any
297    /// trampolines that require an executable stack.
298    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
299      return 0;
300    }
301
302    bool usesSunStyleELFSectionSwitchSyntax() const {
303      return SunStyleELFSectionSwitchSyntax;
304    }
305
306    bool usesELFSectionDirectiveForBSS() const {
307      return UsesELFSectionDirectiveForBSS;
308    }
309
310    bool hasMicrosoftFastStdCallMangling() const {
311      return HasMicrosoftFastStdCallMangling;
312    }
313
314    // Accessors.
315    //
316    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
317    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
318    bool hasStaticCtorDtorReferenceInStaticMode() const {
319      return HasStaticCtorDtorReferenceInStaticMode;
320    }
321    unsigned getMaxInstLength() const {
322      return MaxInstLength;
323    }
324    const char *getPCSymbol() const {
325      return PCSymbol;
326    }
327    char getSeparatorChar() const {
328      return SeparatorChar;
329    }
330    unsigned getCommentColumn() const {
331      return CommentColumn;
332    }
333    const char *getCommentString() const {
334      return CommentString;
335    }
336    const char *getLabelSuffix() const {
337      return LabelSuffix;
338    }
339    const char *getGlobalPrefix() const {
340      return GlobalPrefix;
341    }
342    const char *getPrivateGlobalPrefix() const {
343      return PrivateGlobalPrefix;
344    }
345    const char *getLinkerPrivateGlobalPrefix() const {
346      return LinkerPrivateGlobalPrefix;
347    }
348    const char *getInlineAsmStart() const {
349      return InlineAsmStart;
350    }
351    const char *getInlineAsmEnd() const {
352      return InlineAsmEnd;
353    }
354    unsigned getAssemblerDialect() const {
355      return AssemblerDialect;
356    }
357    bool doesAllowQuotesInName() const {
358      return AllowQuotesInName;
359    }
360    bool doesAllowNameToStartWithDigit() const {
361      return AllowNameToStartWithDigit;
362    }
363    bool doesAllowPeriodsInName() const {
364      return AllowPeriodsInName;
365    }
366    const char *getZeroDirective() const {
367      return ZeroDirective;
368    }
369    const char *getAsciiDirective() const {
370      return AsciiDirective;
371    }
372    const char *getAscizDirective() const {
373      return AscizDirective;
374    }
375    const char *getAlignDirective() const {
376      return AlignDirective;
377    }
378    bool getAlignmentIsInBytes() const {
379      return AlignmentIsInBytes;
380    }
381    unsigned getTextAlignFillValue() const {
382      return TextAlignFillValue;
383    }
384    const char *getGlobalDirective() const {
385      return GlobalDirective;
386    }
387    const char *getExternDirective() const {
388      return ExternDirective;
389    }
390    bool hasSetDirective() const { return HasSetDirective; }
391    bool hasLCOMMDirective() const { return HasLCOMMDirective; }
392    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
393    bool getCOMMDirectiveAlignmentIsInBytes() const {
394      return COMMDirectiveAlignmentIsInBytes;
395    }
396    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
397    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
398    const char *getWeakRefDirective() const { return WeakRefDirective; }
399    const char *getWeakDefDirective() const { return WeakDefDirective; }
400    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
401
402    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
403    MCSymbolAttr getProtectedVisibilityAttr() const {
404      return ProtectedVisibilityAttr;
405    }
406    bool hasLEB128() const {
407      return HasLEB128;
408    }
409    bool doesSupportDebugInformation() const {
410      return SupportsDebugInformation;
411    }
412    bool doesSupportExceptionHandling() const {
413      return ExceptionsType != ExceptionHandling::None;
414    }
415    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
416      return ExceptionsType;
417    }
418    bool doesDwarfRequireFrameSection() const {
419      return DwarfRequiresFrameSection;
420    }
421    bool doesDwarfUsesInlineInfoSection() const {
422      return DwarfUsesInlineInfoSection;
423    }
424    const char *getDwarfSectionOffsetDirective() const {
425      return DwarfSectionOffsetDirective;
426    }
427    bool doesDwarfUsesAbsoluteLabelForStmtList() const {
428      return DwarfUsesAbsoluteLabelForStmtList;
429    }
430    bool doesDwarfUsesLabelOffsetForRanges() const {
431      return DwarfUsesLabelOffsetForRanges;
432    }
433    const char *const *getAsmCBE() const {
434      return AsmTransCBE;
435    }
436  };
437}
438
439#endif
440