AsmPrinter.h revision 51b776d25915ca7fbfc14578ff479352a772da06 
1//===-- llvm/CodeGen/AsmPrinter.h - AsmPrinter Framework --------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This class is intended to be used as a base class for target-specific
11// asmwriters.  This class primarily takes care of printing global constants,
12// which are printed in a very similar way across all targets.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_CODEGEN_ASMPRINTER_H
17#define LLVM_CODEGEN_ASMPRINTER_H
18
19#include "llvm/CodeGen/MachineFunctionPass.h"
20#include "llvm/Support/DataTypes.h"
21
22namespace llvm {
23  class Constant;
24  class ConstantArray;
25  class Mangler;
26  class GlobalVariable;
27
28  class AsmPrinter : public MachineFunctionPass {
29    /// CurrentSection - The current section we are emitting to.  This is
30    /// controlled and used by the SwitchSection method.
31    std::string CurrentSection;
32
33    /// FunctionNumber - This provides a unique ID for each function emitted in
34    /// this translation unit.  It is autoincremented by SetupMachineFunction,
35    /// and can be accessed with getFunctionNumber() and
36    /// IncrementFunctionNumber().
37    ///
38    unsigned FunctionNumber;
39
40  public:
41    /// Output stream on which we're printing assembly code.
42    ///
43    std::ostream &O;
44
45    /// Target machine description.
46    ///
47    TargetMachine &TM;
48
49    /// Name-mangler for global names.
50    ///
51    Mangler *Mang;
52
53    /// Cache of mangled name for current function. This is recalculated at the
54    /// beginning of each call to runOnMachineFunction().
55    ///
56    std::string CurrentFnName;
57
58    //===------------------------------------------------------------------===//
59    // Properties to be set by the derived class ctor, used to configure the
60    // asmwriter.
61
62    /// CommentString - This indicates the comment character used by the
63    /// assembler.
64    const char *CommentString;     // Defaults to "#"
65
66    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
67    /// onto all global symbols.  This is often used for "_" or ".".
68    const char *GlobalPrefix;    // Defaults to ""
69
70    /// PrivateGlobalPrefix - This prefix is used for globals like constant
71    /// pool entries that are completely private to the .o file and should not
72    /// have names in the .o file.  This is often "." or "L".
73    const char *PrivateGlobalPrefix;   // Defaults to "."
74
75    /// GlobalVarAddrPrefix/Suffix - If these are nonempty, these strings
76    /// will enclose any GlobalVariable (that isn't a function)
77    ///
78    const char *GlobalVarAddrPrefix;       // Defaults to ""
79    const char *GlobalVarAddrSuffix;       // Defaults to ""
80
81    /// FunctionAddrPrefix/Suffix - If these are nonempty, these strings
82    /// will enclose any GlobalVariable that points to a function.
83    /// For example, this is used by the IA64 backend to materialize
84    /// function descriptors, by decorating the ".data8" object with the
85    /// @fptr( ) link-relocation operator.
86    ///
87    const char *FunctionAddrPrefix;       // Defaults to ""
88    const char *FunctionAddrSuffix;       // Defaults to ""
89
90    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
91    /// emit before and after an inline assmebly statement.
92    const char *InlineAsmStart;           // Defaults to "#APP\n"
93    const char *InlineAsmEnd;             // Defaults to "#NO_APP\n"
94
95    //===--- Data Emission Directives -------------------------------------===//
96
97    /// ZeroDirective - this should be set to the directive used to get some
98    /// number of zero bytes emitted to the current section.  Common cases are
99    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
100    /// Data*bitsDirective's will be used to emit zero bytes.
101    const char *ZeroDirective;   // Defaults to "\t.zero\t"
102    const char *ZeroDirectiveSuffix;  // Defaults to ""
103
104    /// AsciiDirective - This directive allows emission of an ascii string with
105    /// the standard C escape characters embedded into it.
106    const char *AsciiDirective;  // Defaults to "\t.ascii\t"
107
108    /// AscizDirective - If not null, this allows for special handling of
109    /// zero terminated strings on this target.  This is commonly supported as
110    /// ".asciz".  If a target doesn't support this, it can be set to null.
111    const char *AscizDirective;  // Defaults to "\t.asciz\t"
112
113    /// DataDirectives - These directives are used to output some unit of
114    /// integer data to the current section.  If a data directive is set to
115    /// null, smaller data directives will be used to emit the large sizes.
116    const char *Data8bitsDirective;   // Defaults to "\t.byte\t"
117    const char *Data16bitsDirective;  // Defaults to "\t.short\t"
118    const char *Data32bitsDirective;  // Defaults to "\t.long\t"
119    const char *Data64bitsDirective;  // Defaults to "\t.quad\t"
120
121    //===--- Alignment Information ----------------------------------------===//
122
123    /// AlignDirective - The directive used to emit round up to an alignment
124    /// boundary.
125    ///
126    const char *AlignDirective;       // Defaults to "\t.align\t"
127
128    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
129    /// emits ".align N" directives, where N is the number of bytes to align to.
130    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
131    /// boundary.
132    bool AlignmentIsInBytes;          // Defaults to true
133
134    //===--- Section Switching Directives ---------------------------------===//
135
136    /// SwitchToSectionDirective - This is the directive used when we want to
137    /// emit a global to an arbitrary section.  The section name is emited after
138    /// this.
139    const char *SwitchToSectionDirective;  // Defaults to "\t.section\t"
140    bool MLSections;  // True if Microsoft ML assembler is targetted
141
142    /// ConstantPoolSection - This is the section that we SwitchToSection right
143    /// before emitting the constant pool for a function.
144    const char *ConstantPoolSection;     // Defaults to "\t.section .rodata\n"
145
146    /// JumpTableSection - This is the section that we SwitchToSection right
147    /// before emitting the jump tables for a function.
148    const char *JumpTableSection;     // Defaults to "\t.section .rodata\n"
149
150    /// StaticCtorsSection - This is the directive that is emitted to switch to
151    /// a section to emit the static constructor list.
152    /// Defaults to "\t.section .ctors,\"aw\",@progbits".
153    const char *StaticCtorsSection;
154
155    /// StaticDtorsSection - This is the directive that is emitted to switch to
156    /// a section to emit the static destructor list.
157    /// Defaults to "\t.section .dtors,\"aw\",@progbits".
158    const char *StaticDtorsSection;
159
160    //===--- Global Variable Emission Directives --------------------------===//
161
162    /// LCOMMDirective - This is the name of a directive (if supported) that can
163    /// be used to efficiently declare a local (internal) block of zero
164    /// initialized data in the .bss/.data section.  The syntax expected is:
165    ///    <LCOMMDirective> SYMBOLNAME LENGTHINBYTES, ALIGNMENT
166    const char *LCOMMDirective;          // Defaults to null.
167
168    const char *COMMDirective;           // Defaults to "\t.comm\t".
169
170    /// COMMDirectiveTakesAlignment - True if COMMDirective take a third
171    /// argument that specifies the alignment of the declaration.
172    bool COMMDirectiveTakesAlignment;    // Defaults to true.
173
174    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
175    /// directives, this is true for most ELF targets.
176    bool HasDotTypeDotSizeDirective;     // Defaults to true.
177
178  protected:
179    AsmPrinter(std::ostream &o, TargetMachine &TM);
180
181  public:
182    /// SwitchSection - Switch to the specified section of the executable if we
183    /// are not already in it!  If GV is non-null and if the global has an
184    /// explicitly requested section, we switch to the section indicated for the
185    /// global instead of NewSection.
186    ///
187    /// If the new section is an empty string, this method forgets what the
188    /// current section is, but does not emit a .section directive.
189    ///
190    void SwitchSection(const char *NewSection, const GlobalValue *GV);
191
192    /// getPreferredAlignmentLog - Return the preferred alignment of the
193    /// specified global, returned in log form.  This includes an explicitly
194    /// requested alignment (if the global has one).
195    unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
196  protected:
197    /// doInitialization - Set up the AsmPrinter when we are working on a new
198    /// module.  If your pass overrides this, it must make sure to explicitly
199    /// call this implementation.
200    bool doInitialization(Module &M);
201
202    /// doFinalization - Shut down the asmprinter.  If you override this in your
203    /// pass, you must make sure to call it explicitly.
204    bool doFinalization(Module &M);
205
206    /// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
207    /// instruction, using the specified assembler variant.  Targets should
208    /// override this to format as appropriate.  This method can return true if
209    /// the operand is erroneous.
210    virtual bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
211                                 unsigned AsmVariant, const char *ExtraCode);
212
213    /// PrintAsmMemoryOperand - Print the specified operand of MI, an INLINEASM
214    /// instruction, using the specified assembler variant as an address.
215    /// Targets should override this to format as appropriate.  This method can
216    /// return true if the operand is erroneous.
217    virtual bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
218                                       unsigned AsmVariant,
219                                       const char *ExtraCode);
220
221    /// SetupMachineFunction - This should be called when a new MachineFunction
222    /// is being processed from runOnMachineFunction.
223    void SetupMachineFunction(MachineFunction &MF);
224
225    /// getFunctionNumber - Return a unique ID for the current function.
226    ///
227    unsigned getFunctionNumber() const { return FunctionNumber; }
228
229    /// IncrementFunctionNumber - Increase Function Number.  AsmPrinters should
230    /// not normally call this, as the counter is automatically bumped by
231    /// SetupMachineFunction.
232    void IncrementFunctionNumber() { FunctionNumber++; }
233
234    /// EmitConstantPool - Print to the current output stream assembly
235    /// representations of the constants in the constant pool MCP. This is
236    /// used to print out constants which have been "spilled to memory" by
237    /// the code generator.
238    ///
239    void EmitConstantPool(MachineConstantPool *MCP);
240
241    /// EmitJumpTableInfo - Print assembly representations of the jump tables
242    /// used by the current function to the current output stream.
243    ///
244    void EmitJumpTableInfo(MachineJumpTableInfo *MJTI);
245
246    /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
247    /// special global used by LLVM.  If so, emit it and return true, otherwise
248    /// do nothing and return false.
249    bool EmitSpecialLLVMGlobal(const GlobalVariable *GV);
250
251    /// EmitAlignment - Emit an alignment directive to the specified power of
252    /// two boundary.  For example, if you pass in 3 here, you will get an 8
253    /// byte alignment.  If a global value is specified, and if that global has
254    /// an explicit alignment requested, it will override the alignment request.
255    void EmitAlignment(unsigned NumBits, const GlobalValue *GV = 0) const;
256
257    /// EmitZeros - Emit a block of zeros.
258    ///
259    void EmitZeros(uint64_t NumZeros) const;
260
261    /// EmitString - Emit a zero-byte-terminated string constant.
262    ///
263    virtual void EmitString(const ConstantArray *CVA) const;
264
265    /// EmitConstantValueOnly - Print out the specified constant, without a
266    /// storage class.  Only constants of first-class type are allowed here.
267    void EmitConstantValueOnly(const Constant *CV);
268
269    /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
270    ///
271    void EmitGlobalConstant(const Constant* CV);
272
273    /// printInlineAsm - This method formats and prints the specified machine
274    /// instruction that is an inline asm.
275    void printInlineAsm(const MachineInstr *MI) const;
276
277    /// printBasicBlockLabel - This method prints the label for the specified
278    /// MachineBasicBlock
279    virtual void printBasicBlockLabel(const MachineBasicBlock *MBB) const;
280
281  private:
282    void EmitXXStructorList(Constant *List);
283
284  };
285}
286
287#endif
288