MCAsmInfo.h revision b9a01bcf486814a44098745920d43daaf9f7c260 
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    /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
45    /// emit a ".reference .constructors_used" or ".reference .destructors_used"
46    /// directive after the a static ctor/dtor list.  This directive is only
47    /// emitted in Static relocation model.
48    bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
49
50    /// MaxInstLength - This is the maximum possible length of an instruction,
51    /// which is needed to compute the size of an inline asm.
52    unsigned MaxInstLength;                  // Defaults to 4.
53
54    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
55    /// relative expressions.
56    const char *PCSymbol;                    // Defaults to "$".
57
58    /// SeparatorChar - This character, if specified, is used to separate
59    /// instructions from each other when on the same line.  This is used to
60    /// measure inline asm instructions.
61    char SeparatorChar;                      // Defaults to ';'
62
63    /// CommentColumn - This indicates the comment num (zero-based) at
64    /// which asm comments should be printed.
65    unsigned CommentColumn;                  // Defaults to 40
66
67    /// CommentString - This indicates the comment character used by the
68    /// assembler.
69    const char *CommentString;               // Defaults to "#"
70
71    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
72    /// onto all global symbols.  This is often used for "_" or ".".
73    const char *GlobalPrefix;                // Defaults to ""
74
75    /// PrivateGlobalPrefix - This prefix is used for globals like constant
76    /// pool entries that are completely private to the .s file and should not
77    /// have names in the .o file.  This is often "." or "L".
78    const char *PrivateGlobalPrefix;         // Defaults to "."
79
80    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
81    /// be passed through the assembler but be removed by the linker.  This
82    /// is "l" on Darwin, currently used for some ObjC metadata.
83    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
84
85    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
86    /// emit before and after an inline assembly statement.
87    const char *InlineAsmStart;              // Defaults to "#APP\n"
88    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
89
90    /// AssemblerDialect - Which dialect of an assembler variant to use.
91    unsigned AssemblerDialect;               // Defaults to 0
92
93    /// AllowQuotesInName - This is true if the assembler allows for complex
94    /// symbol names to be surrounded in quotes.  This defaults to false.
95    bool AllowQuotesInName;
96
97    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
98    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
99    bool AllowNameToStartWithDigit;
100
101    /// AllowPeriodsInName - This is true if the assembler allows periods in
102    /// symbol names.  This defaults to true.
103    bool AllowPeriodsInName;
104
105    //===--- Data Emission Directives -------------------------------------===//
106
107    /// ZeroDirective - this should be set to the directive used to get some
108    /// number of zero bytes emitted to the current section.  Common cases are
109    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
110    /// Data*bitsDirective's will be used to emit zero bytes.
111    const char *ZeroDirective;               // Defaults to "\t.zero\t"
112
113    /// AsciiDirective - This directive allows emission of an ascii string with
114    /// the standard C escape characters embedded into it.
115    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
116
117    /// AscizDirective - If not null, this allows for special handling of
118    /// zero terminated strings on this target.  This is commonly supported as
119    /// ".asciz".  If a target doesn't support this, it can be set to null.
120    const char *AscizDirective;              // Defaults to "\t.asciz\t"
121
122    /// DataDirectives - These directives are used to output some unit of
123    /// integer data to the current section.  If a data directive is set to
124    /// null, smaller data directives will be used to emit the large sizes.
125    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
126    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
127    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
128    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
129
130    /// GPRel32Directive - if non-null, a directive that is used to emit a word
131    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
132    /// on Mips or .gprel32 on Alpha.
133    const char *GPRel32Directive;            // Defaults to NULL.
134
135    /// getDataASDirective - Return the directive that should be used to emit
136    /// data of the specified size to the specified numeric address space.
137    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
138      assert(AS != 0 && "Don't know the directives for default addr space");
139      return 0;
140    }
141
142    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
143    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
144    /// normal ELF syntax (,"a,w") in .section directives.
145    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
146
147    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
148    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
149    /// which doesn't support the '.bss' directive only.
150    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
151
152    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
153    /// style mangling for functions with X86_StdCall/X86_FastCall calling
154    /// convention.
155    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
156
157    //===--- Alignment Information ----------------------------------------===//
158
159    /// AlignDirective - The directive used to emit round up to an alignment
160    /// boundary.
161    ///
162    const char *AlignDirective;              // Defaults to "\t.align\t"
163
164    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
165    /// emits ".align N" directives, where N is the number of bytes to align to.
166    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
167    /// boundary.
168    bool AlignmentIsInBytes;                 // Defaults to true
169
170    /// TextAlignFillValue - If non-zero, this is used to fill the executable
171    /// space created as the result of a alignment directive.
172    unsigned TextAlignFillValue;             // Defaults to 0
173
174    //===--- Global Variable Emission Directives --------------------------===//
175
176    /// GlobalDirective - This is the directive used to declare a global entity.
177    ///
178    const char *GlobalDirective;             // Defaults to NULL.
179
180    /// ExternDirective - This is the directive used to declare external
181    /// globals.
182    ///
183    const char *ExternDirective;             // Defaults to NULL.
184
185    /// HasSetDirective - True if the assembler supports the .set directive.
186    bool HasSetDirective;                    // Defaults to true.
187
188    /// HasLCOMMDirective - This is true if the target supports the .lcomm
189    /// directive.
190    bool HasLCOMMDirective;                  // Defaults to false.
191
192    /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional
193    /// alignment is to be specified in bytes instead of log2(n).
194    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
195
196    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
197    /// directives, this is true for most ELF targets.
198    bool HasDotTypeDotSizeDirective;         // Defaults to true.
199
200    /// HasSingleParameterDotFile - True if the target has a single parameter
201    /// .file directive, this is true for ELF targets.
202    bool HasSingleParameterDotFile;          // Defaults to true.
203
204    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
205    /// directive.
206    bool HasNoDeadStrip;                     // Defaults to false.
207
208    /// WeakRefDirective - This directive, if non-null, is used to declare a
209    /// global as being a weak undefined symbol.
210    const char *WeakRefDirective;            // Defaults to NULL.
211
212    /// WeakDefDirective - This directive, if non-null, is used to declare a
213    /// global as being a weak defined symbol.
214    const char *WeakDefDirective;            // Defaults to NULL.
215
216    /// LinkOnceDirective - This directive, if non-null is used to declare a
217    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
218    const char *LinkOnceDirective;           // Defaults to NULL.
219
220    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
221    /// declare a symbol as having hidden visibility.
222    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
223
224    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
225    /// to declare a symbol as having protected visibility.
226    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
227
228    //===--- Dwarf Emission Directives -----------------------------------===//
229
230    /// HasLEB128 - True if target asm supports leb128 directives.
231    bool HasLEB128;                          // Defaults to false.
232
233    /// hasDotLocAndDotFile - True if target asm supports .loc and .file
234    /// directives for emitting debugging information.
235    bool HasDotLocAndDotFile;                // Defaults to false.
236
237    /// SupportsDebugInformation - True if target supports emission of debugging
238    /// information.
239    bool SupportsDebugInformation;           // Defaults to false.
240
241    /// SupportsExceptionHandling - True if target supports exception handling.
242    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
243
244    /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
245    bool DwarfRequiresFrameSection;          // Defaults to true.
246
247    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
248    /// encode inline subroutine information.
249    bool DwarfUsesInlineInfoSection;         // Defaults to false.
250
251    /// DwarfSectionOffsetDirective - Special section offset directive.
252    const char* DwarfSectionOffsetDirective; // Defaults to NULL
253
254    //===--- CBE Asm Translation Table -----------------------------------===//
255
256    const char *const *AsmTransCBE;          // Defaults to empty
257
258  public:
259    explicit MCAsmInfo();
260    virtual ~MCAsmInfo();
261
262    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
263    static unsigned getSLEB128Size(int Value);
264    static unsigned getULEB128Size(unsigned Value);
265
266    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
267
268    // Data directive accessors.
269    //
270    const char *getData8bitsDirective(unsigned AS = 0) const {
271      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
272    }
273    const char *getData16bitsDirective(unsigned AS = 0) const {
274      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
275    }
276    const char *getData32bitsDirective(unsigned AS = 0) const {
277      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
278    }
279    const char *getData64bitsDirective(unsigned AS = 0) const {
280      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
281    }
282    const char *getGPRel32Directive() const { return GPRel32Directive; }
283
284    /// getNonexecutableStackSection - Targets can implement this method to
285    /// specify a section to switch to if the translation unit doesn't have any
286    /// trampolines that require an executable stack.
287    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
288      return 0;
289    }
290
291    bool usesSunStyleELFSectionSwitchSyntax() const {
292      return SunStyleELFSectionSwitchSyntax;
293    }
294
295    bool usesELFSectionDirectiveForBSS() const {
296      return UsesELFSectionDirectiveForBSS;
297    }
298
299    bool hasMicrosoftFastStdCallMangling() const {
300      return HasMicrosoftFastStdCallMangling;
301    }
302
303    // Accessors.
304    //
305    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
306    bool hasStaticCtorDtorReferenceInStaticMode() const {
307      return HasStaticCtorDtorReferenceInStaticMode;
308    }
309    unsigned getMaxInstLength() const {
310      return MaxInstLength;
311    }
312    const char *getPCSymbol() const {
313      return PCSymbol;
314    }
315    char getSeparatorChar() const {
316      return SeparatorChar;
317    }
318    unsigned getCommentColumn() const {
319      return CommentColumn;
320    }
321    const char *getCommentString() const {
322      return CommentString;
323    }
324    const char *getGlobalPrefix() const {
325      return GlobalPrefix;
326    }
327    const char *getPrivateGlobalPrefix() const {
328      return PrivateGlobalPrefix;
329    }
330    const char *getLinkerPrivateGlobalPrefix() const {
331      return LinkerPrivateGlobalPrefix;
332    }
333    const char *getInlineAsmStart() const {
334      return InlineAsmStart;
335    }
336    const char *getInlineAsmEnd() const {
337      return InlineAsmEnd;
338    }
339    unsigned getAssemblerDialect() const {
340      return AssemblerDialect;
341    }
342    bool doesAllowQuotesInName() const {
343      return AllowQuotesInName;
344    }
345    bool doesAllowNameToStartWithDigit() const {
346      return AllowNameToStartWithDigit;
347    }
348    bool doesAllowPeriodsInName() const {
349      return AllowPeriodsInName;
350    }
351    const char *getZeroDirective() const {
352      return ZeroDirective;
353    }
354    const char *getAsciiDirective() const {
355      return AsciiDirective;
356    }
357    const char *getAscizDirective() const {
358      return AscizDirective;
359    }
360    const char *getAlignDirective() const {
361      return AlignDirective;
362    }
363    bool getAlignmentIsInBytes() const {
364      return AlignmentIsInBytes;
365    }
366    unsigned getTextAlignFillValue() const {
367      return TextAlignFillValue;
368    }
369    const char *getGlobalDirective() const {
370      return GlobalDirective;
371    }
372    const char *getExternDirective() const {
373      return ExternDirective;
374    }
375    bool hasSetDirective() const { return HasSetDirective; }
376    bool hasLCOMMDirective() const { return HasLCOMMDirective; }
377    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
378    bool getCOMMDirectiveAlignmentIsInBytes() const {
379      return COMMDirectiveAlignmentIsInBytes;
380    }
381    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
382    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
383    const char *getWeakRefDirective() const { return WeakRefDirective; }
384    const char *getWeakDefDirective() const { return WeakDefDirective; }
385    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
386
387    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
388    MCSymbolAttr getProtectedVisibilityAttr() const {
389      return ProtectedVisibilityAttr;
390    }
391    bool hasLEB128() const {
392      return HasLEB128;
393    }
394    bool hasDotLocAndDotFile() const {
395      return HasDotLocAndDotFile;
396    }
397    bool doesSupportDebugInformation() const {
398      return SupportsDebugInformation;
399    }
400    bool doesSupportExceptionHandling() const {
401      return ExceptionsType != ExceptionHandling::None;
402    }
403    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
404      return ExceptionsType;
405    }
406    bool doesDwarfRequireFrameSection() const {
407      return DwarfRequiresFrameSection;
408    }
409    bool doesDwarfUsesInlineInfoSection() const {
410      return DwarfUsesInlineInfoSection;
411    }
412    const char *getDwarfSectionOffsetDirective() const {
413      return DwarfSectionOffsetDirective;
414    }
415    const char *const *getAsmCBE() const {
416      return AsmTransCBE;
417    }
418  };
419}
420
421#endif
422