NVPTXAsmPrinter.h revision 288943 
1//===-- NVPTXAsmPrinter.h - NVPTX LLVM assembly writer --------------------===//
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 printer that converts from our internal representation
11// of machine-dependent LLVM code to NVPTX assembly language.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_LIB_TARGET_NVPTX_NVPTXASMPRINTER_H
16#define LLVM_LIB_TARGET_NVPTX_NVPTXASMPRINTER_H
17
18#include "NVPTX.h"
19#include "NVPTXSubtarget.h"
20#include "NVPTXTargetMachine.h"
21#include "llvm/ADT/SmallString.h"
22#include "llvm/ADT/StringExtras.h"
23#include "llvm/CodeGen/AsmPrinter.h"
24#include "llvm/IR/Function.h"
25#include "llvm/MC/MCAsmInfo.h"
26#include "llvm/MC/MCExpr.h"
27#include "llvm/MC/MCSymbol.h"
28#include "llvm/Support/CommandLine.h"
29#include "llvm/Support/FormattedStream.h"
30#include "llvm/Target/TargetMachine.h"
31#include <fstream>
32
33// The ptx syntax and format is very different from that usually seem in a .s
34// file,
35// therefore we are not able to use the MCAsmStreamer interface here.
36//
37// We are handcrafting the output method here.
38//
39// A better approach is to clone the MCAsmStreamer to a MCPTXAsmStreamer
40// (subclass of MCStreamer).
41
42namespace llvm {
43  class MCOperand;
44
45class LineReader {
46private:
47  unsigned theCurLine;
48  std::ifstream fstr;
49  char buff[512];
50  std::string theFileName;
51  SmallVector<unsigned, 32> lineOffset;
52public:
53  LineReader(std::string filename) {
54    theCurLine = 0;
55    fstr.open(filename.c_str());
56    theFileName = filename;
57  }
58  std::string fileName() { return theFileName; }
59  ~LineReader() { fstr.close(); }
60  std::string readLine(unsigned line);
61};
62
63class LLVM_LIBRARY_VISIBILITY NVPTXAsmPrinter : public AsmPrinter {
64
65  class AggBuffer {
66    // Used to buffer the emitted string for initializing global
67    // aggregates.
68    //
69    // Normally an aggregate (array, vector or structure) is emitted
70    // as a u8[]. However, if one element/field of the aggregate
71    // is a non-NULL address, then the aggregate is emitted as u32[]
72    // or u64[].
73    //
74    // We first layout the aggregate in 'buffer' in bytes, except for
75    // those symbol addresses. For the i-th symbol address in the
76    //aggregate, its corresponding 4-byte or 8-byte elements in 'buffer'
77    // are filled with 0s. symbolPosInBuffer[i-1] records its position
78    // in 'buffer', and Symbols[i-1] records the Value*.
79    //
80    // Once we have this AggBuffer setup, we can choose how to print
81    // it out.
82  public:
83    unsigned numSymbols;   // number of symbol addresses
84
85  private:
86    const unsigned size;   // size of the buffer in bytes
87    std::vector<unsigned char> buffer; // the buffer
88    SmallVector<unsigned, 4> symbolPosInBuffer;
89    SmallVector<const Value *, 4> Symbols;
90    // SymbolsBeforeStripping[i] is the original form of Symbols[i] before
91    // stripping pointer casts, i.e.,
92    // Symbols[i] == SymbolsBeforeStripping[i]->stripPointerCasts().
93    //
94    // We need to keep these values because AggBuffer::print decides whether to
95    // emit a "generic()" cast for Symbols[i] depending on the address space of
96    // SymbolsBeforeStripping[i].
97    SmallVector<const Value *, 4> SymbolsBeforeStripping;
98    unsigned curpos;
99    raw_ostream &O;
100    NVPTXAsmPrinter &AP;
101    bool EmitGeneric;
102
103  public:
104    AggBuffer(unsigned size, raw_ostream &O, NVPTXAsmPrinter &AP)
105        : size(size), buffer(size), O(O), AP(AP) {
106      curpos = 0;
107      numSymbols = 0;
108      EmitGeneric = AP.EmitGeneric;
109    }
110    unsigned addBytes(unsigned char *Ptr, int Num, int Bytes) {
111      assert((curpos + Num) <= size);
112      assert((curpos + Bytes) <= size);
113      for (int i = 0; i < Num; ++i) {
114        buffer[curpos] = Ptr[i];
115        curpos++;
116      }
117      for (int i = Num; i < Bytes; ++i) {
118        buffer[curpos] = 0;
119        curpos++;
120      }
121      return curpos;
122    }
123    unsigned addZeros(int Num) {
124      assert((curpos + Num) <= size);
125      for (int i = 0; i < Num; ++i) {
126        buffer[curpos] = 0;
127        curpos++;
128      }
129      return curpos;
130    }
131    void addSymbol(const Value *GVar, const Value *GVarBeforeStripping) {
132      symbolPosInBuffer.push_back(curpos);
133      Symbols.push_back(GVar);
134      SymbolsBeforeStripping.push_back(GVarBeforeStripping);
135      numSymbols++;
136    }
137    void print() {
138      if (numSymbols == 0) {
139        // print out in bytes
140        for (unsigned i = 0; i < size; i++) {
141          if (i)
142            O << ", ";
143          O << (unsigned int) buffer[i];
144        }
145      } else {
146        // print out in 4-bytes or 8-bytes
147        unsigned int pos = 0;
148        unsigned int nSym = 0;
149        unsigned int nextSymbolPos = symbolPosInBuffer[nSym];
150        unsigned int nBytes = 4;
151        if (static_cast<const NVPTXTargetMachine &>(AP.TM).is64Bit())
152          nBytes = 8;
153        for (pos = 0; pos < size; pos += nBytes) {
154          if (pos)
155            O << ", ";
156          if (pos == nextSymbolPos) {
157            const Value *v = Symbols[nSym];
158            const Value *v0 = SymbolsBeforeStripping[nSym];
159            if (const GlobalValue *GVar = dyn_cast<GlobalValue>(v)) {
160              MCSymbol *Name = AP.getSymbol(GVar);
161              PointerType *PTy = dyn_cast<PointerType>(v0->getType());
162              bool IsNonGenericPointer = false; // Is v0 a non-generic pointer?
163              if (PTy && PTy->getAddressSpace() != 0) {
164                IsNonGenericPointer = true;
165              }
166              if (EmitGeneric && !isa<Function>(v) && !IsNonGenericPointer) {
167                O << "generic(";
168                Name->print(O, AP.MAI);
169                O << ")";
170              } else {
171                Name->print(O, AP.MAI);
172              }
173            } else if (const ConstantExpr *CExpr = dyn_cast<ConstantExpr>(v0)) {
174              const MCExpr *Expr =
175                AP.lowerConstantForGV(cast<Constant>(CExpr), false);
176              AP.printMCExpr(*Expr, O);
177            } else
178              llvm_unreachable("symbol type unknown");
179            nSym++;
180            if (nSym >= numSymbols)
181              nextSymbolPos = size + 1;
182            else
183              nextSymbolPos = symbolPosInBuffer[nSym];
184          } else if (nBytes == 4)
185            O << *(unsigned int *)(&buffer[pos]);
186          else
187            O << *(unsigned long long *)(&buffer[pos]);
188        }
189      }
190    }
191  };
192
193  friend class AggBuffer;
194
195  void emitSrcInText(StringRef filename, unsigned line);
196
197private:
198  const char *getPassName() const override { return "NVPTX Assembly Printer"; }
199
200  const Function *F;
201  std::string CurrentFnName;
202
203  void EmitBasicBlockStart(const MachineBasicBlock &MBB) const override;
204  void EmitFunctionEntryLabel() override;
205  void EmitFunctionBodyStart() override;
206  void EmitFunctionBodyEnd() override;
207  void emitImplicitDef(const MachineInstr *MI) const override;
208
209  void EmitInstruction(const MachineInstr *) override;
210  void lowerToMCInst(const MachineInstr *MI, MCInst &OutMI);
211  bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp);
212  MCOperand GetSymbolRef(const MCSymbol *Symbol);
213  unsigned encodeVirtualRegister(unsigned Reg);
214
215  void EmitAlignment(unsigned NumBits, const GlobalValue *GV = nullptr) const {}
216
217  void printVecModifiedImmediate(const MachineOperand &MO, const char *Modifier,
218                                 raw_ostream &O);
219  void printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
220                       const char *Modifier = nullptr);
221  void printImplicitDef(const MachineInstr *MI, raw_ostream &O) const;
222  void printModuleLevelGV(const GlobalVariable *GVar, raw_ostream &O,
223                          bool = false);
224  void printParamName(int paramIndex, raw_ostream &O);
225  void printParamName(Function::const_arg_iterator I, int paramIndex,
226                      raw_ostream &O);
227  void emitGlobals(const Module &M);
228  void emitHeader(Module &M, raw_ostream &O, const NVPTXSubtarget &STI);
229  void emitKernelFunctionDirectives(const Function &F, raw_ostream &O) const;
230  void emitVirtualRegister(unsigned int vr, raw_ostream &);
231  void emitFunctionExternParamList(const MachineFunction &MF);
232  void emitFunctionParamList(const Function *, raw_ostream &O);
233  void emitFunctionParamList(const MachineFunction &MF, raw_ostream &O);
234  void setAndEmitFunctionVirtualRegisters(const MachineFunction &MF);
235  void emitFunctionTempData(const MachineFunction &MF, unsigned &FrameSize);
236  bool isImageType(const Type *Ty);
237  void printReturnValStr(const Function *, raw_ostream &O);
238  void printReturnValStr(const MachineFunction &MF, raw_ostream &O);
239  bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
240                       unsigned AsmVariant, const char *ExtraCode,
241                       raw_ostream &) override;
242  void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
243                    const char *Modifier = nullptr);
244  bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
245                             unsigned AsmVariant, const char *ExtraCode,
246                             raw_ostream &) override;
247
248  const MCExpr *lowerConstantForGV(const Constant *CV, bool ProcessingGeneric);
249  void printMCExpr(const MCExpr &Expr, raw_ostream &OS);
250
251protected:
252  bool doInitialization(Module &M) override;
253  bool doFinalization(Module &M) override;
254
255private:
256  std::string CurrentBankselLabelInBasicBlock;
257
258  bool GlobalsEmitted;
259
260  // This is specific per MachineFunction.
261  const MachineRegisterInfo *MRI;
262  // The contents are specific for each
263  // MachineFunction. But the size of the
264  // array is not.
265  typedef DenseMap<unsigned, unsigned> VRegMap;
266  typedef DenseMap<const TargetRegisterClass *, VRegMap> VRegRCMap;
267  VRegRCMap VRegMapping;
268
269  // Cache the subtarget here.
270  const NVPTXSubtarget *nvptxSubtarget;
271
272  // Build the map between type name and ID based on module's type
273  // symbol table.
274  std::map<const Type *, std::string> TypeNameMap;
275
276  // List of variables demoted to a function scope.
277  std::map<const Function *, std::vector<const GlobalVariable *> > localDecls;
278
279  // To record filename to ID mapping
280  std::map<std::string, unsigned> filenameMap;
281  void recordAndEmitFilenames(Module &);
282
283  void emitPTXGlobalVariable(const GlobalVariable *GVar, raw_ostream &O);
284  void emitPTXAddressSpace(unsigned int AddressSpace, raw_ostream &O) const;
285  std::string getPTXFundamentalTypeStr(const Type *Ty, bool = true) const;
286  void printScalarConstant(const Constant *CPV, raw_ostream &O);
287  void printFPConstant(const ConstantFP *Fp, raw_ostream &O);
288  void bufferLEByte(const Constant *CPV, int Bytes, AggBuffer *aggBuffer);
289  void bufferAggregateConstant(const Constant *CV, AggBuffer *aggBuffer);
290
291  void printOperandProper(const MachineOperand &MO);
292
293  void emitLinkageDirective(const GlobalValue *V, raw_ostream &O);
294  void emitDeclarations(const Module &, raw_ostream &O);
295  void emitDeclaration(const Function *, raw_ostream &O);
296
297  static const char *getRegisterName(unsigned RegNo);
298  void emitDemotedVars(const Function *, raw_ostream &);
299
300  bool lowerImageHandleOperand(const MachineInstr *MI, unsigned OpNo,
301                               MCOperand &MCOp);
302  void lowerImageHandleSymbol(unsigned Index, MCOperand &MCOp);
303
304  bool isLoopHeaderOfNoUnroll(const MachineBasicBlock &MBB) const;
305
306  LineReader *reader;
307  LineReader *getReader(std::string);
308
309  // Used to control the need to emit .generic() in the initializer of
310  // module scope variables.
311  // Although ptx supports the hybrid mode like the following,
312  //    .global .u32 a;
313  //    .global .u32 b;
314  //    .global .u32 addr[] = {a, generic(b)}
315  // we have difficulty representing the difference in the NVVM IR.
316  //
317  // Since the address value should always be generic in CUDA C and always
318  // be specific in OpenCL, we use this simple control here.
319  //
320  bool EmitGeneric;
321
322public:
323  NVPTXAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
324      : AsmPrinter(TM, std::move(Streamer)),
325        EmitGeneric(static_cast<NVPTXTargetMachine &>(TM).getDrvInterface() ==
326                    NVPTX::CUDA) {
327    CurrentBankselLabelInBasicBlock = "";
328    reader = nullptr;
329  }
330
331  ~NVPTXAsmPrinter() {
332    if (!reader)
333      delete reader;
334  }
335
336  bool runOnMachineFunction(MachineFunction &F) override {
337    nvptxSubtarget = &F.getSubtarget<NVPTXSubtarget>();
338    return AsmPrinter::runOnMachineFunction(F);
339  }
340  void getAnalysisUsage(AnalysisUsage &AU) const override {
341    AU.addRequired<MachineLoopInfo>();
342    AsmPrinter::getAnalysisUsage(AU);
343  }
344
345  bool ignoreLoc(const MachineInstr &);
346
347  std::string getVirtualRegisterName(unsigned) const;
348
349  DebugLoc prevDebugLoc;
350  void emitLineNumberAsDotLoc(const MachineInstr &);
351};
352} // end of namespace
353
354#endif
355