AsmPrinterInlineAsm.cpp revision 6eb7806a5f5edf460e68f52bdd0fad25f7771873 
1//===-- AsmPrinterInlineAsm.cpp - AsmPrinter Inline Asm Handling ----------===//
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 implements the inline assembler pieces of the AsmPrinter class.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "asm-printer"
15#include "llvm/CodeGen/AsmPrinter.h"
16#include "llvm/InlineAsm.h"
17#include "llvm/LLVMContext.h"
18#include "llvm/Module.h"
19#include "llvm/CodeGen/MachineBasicBlock.h"
20#include "llvm/CodeGen/MachineModuleInfo.h"
21#include "llvm/MC/MCAsmInfo.h"
22#include "llvm/MC/MCStreamer.h"
23#include "llvm/MC/MCSymbol.h"
24#include "llvm/MC/MCParser/AsmParser.h"
25#include "llvm/Target/TargetAsmParser.h"
26#include "llvm/Target/TargetMachine.h"
27#include "llvm/Target/TargetRegistry.h"
28#include "llvm/ADT/OwningPtr.h"
29#include "llvm/ADT/SmallString.h"
30#include "llvm/ADT/Twine.h"
31#include "llvm/Support/ErrorHandling.h"
32#include "llvm/Support/MemoryBuffer.h"
33#include "llvm/Support/SourceMgr.h"
34#include "llvm/Support/raw_ostream.h"
35using namespace llvm;
36
37/// EmitInlineAsm - Emit a blob of inline asm to the output streamer.
38void AsmPrinter::EmitInlineAsm(StringRef Str) const {
39  assert(!Str.empty() && "Can't emit empty inline asm block");
40
41  // Remember if the buffer is nul terminated or not so we can avoid a copy.
42  bool isNullTerminated = Str.back() == 0;
43  if (isNullTerminated)
44    Str = Str.substr(0, Str.size()-1);
45
46  // If the output streamer is actually a .s file, just emit the blob textually.
47  // This is useful in case the asm parser doesn't handle something but the
48  // system assembler does.
49  if (OutStreamer.hasRawTextSupport()) {
50    OutStreamer.EmitRawText(Str);
51    return;
52  }
53
54  SourceMgr SrcMgr;
55
56  // If the current LLVMContext has an inline asm handler, set it in SourceMgr.
57  LLVMContext &LLVMCtx = MMI->getModule()->getContext();
58  bool HasDiagHandler = false;
59  if (void *DiagHandler = LLVMCtx.getInlineAsmDiagnosticHandler()) {
60    unsigned Cookie = 0;  // no cookie yet.
61    SrcMgr.setDiagHandler((SourceMgr::DiagHandlerTy)(intptr_t)DiagHandler,
62                          LLVMCtx.getInlineAsmDiagnosticContext(), Cookie);
63    HasDiagHandler = true;
64  }
65
66  MemoryBuffer *Buffer;
67  if (isNullTerminated)
68    Buffer = MemoryBuffer::getMemBuffer(Str, "<inline asm>");
69  else
70    Buffer = MemoryBuffer::getMemBufferCopy(Str, "<inline asm>");
71
72  // Tell SrcMgr about this buffer, it takes ownership of the buffer.
73  SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
74
75  AsmParser Parser(SrcMgr, OutContext, OutStreamer, *MAI);
76  OwningPtr<TargetAsmParser> TAP(TM.getTarget().createAsmParser(Parser));
77  if (!TAP)
78    llvm_report_error("Inline asm not supported by this streamer because"
79                      " we don't have an asm parser for this target\n");
80  Parser.setTargetParser(*TAP.get());
81
82  // Don't implicitly switch to the text section before the asm.
83  int Res = Parser.Run(/*NoInitialTextSection*/ true,
84                       /*NoFinalize*/ true);
85  if (Res && !HasDiagHandler)
86    llvm_report_error("Error parsing inline asm\n");
87}
88
89
90/// EmitInlineAsm - This method formats and emits the specified machine
91/// instruction that is an inline asm.
92void AsmPrinter::EmitInlineAsm(const MachineInstr *MI) const {
93  assert(MI->isInlineAsm() && "printInlineAsm only works on inline asms");
94
95  unsigned NumOperands = MI->getNumOperands();
96
97  // Count the number of register definitions to find the asm string.
98  unsigned NumDefs = 0;
99  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
100       ++NumDefs)
101    assert(NumDefs != NumOperands-1 && "No asm string?");
102
103  assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
104
105  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
106  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
107
108  // If this asmstr is empty, just print the #APP/#NOAPP markers.
109  // These are useful to see where empty asm's wound up.
110  if (AsmStr[0] == 0) {
111    // Don't emit the comments if writing to a .o file.
112    if (!OutStreamer.hasRawTextSupport()) return;
113
114    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
115                            MAI->getInlineAsmStart());
116    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
117                            MAI->getInlineAsmEnd());
118    return;
119  }
120
121  // Emit the #APP start marker.  This has to happen even if verbose-asm isn't
122  // enabled, so we use EmitRawText.
123  if (OutStreamer.hasRawTextSupport())
124    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
125                            MAI->getInlineAsmStart());
126
127  // Emit the inline asm to a temporary string so we can emit it through
128  // EmitInlineAsm.
129  SmallString<256> StringData;
130  raw_svector_ostream OS(StringData);
131
132  OS << '\t';
133
134  // The variant of the current asmprinter.
135  int AsmPrinterVariant = MAI->getAssemblerDialect();
136
137  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
138  const char *LastEmitted = AsmStr; // One past the last character emitted.
139
140  while (*LastEmitted) {
141    switch (*LastEmitted) {
142    default: {
143      // Not a special case, emit the string section literally.
144      const char *LiteralEnd = LastEmitted+1;
145      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
146             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
147        ++LiteralEnd;
148      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
149        OS.write(LastEmitted, LiteralEnd-LastEmitted);
150      LastEmitted = LiteralEnd;
151      break;
152    }
153    case '\n':
154      ++LastEmitted;   // Consume newline character.
155      OS << '\n';      // Indent code with newline.
156      break;
157    case '$': {
158      ++LastEmitted;   // Consume '$' character.
159      bool Done = true;
160
161      // Handle escapes.
162      switch (*LastEmitted) {
163      default: Done = false; break;
164      case '$':     // $$ -> $
165        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
166          OS << '$';
167        ++LastEmitted;  // Consume second '$' character.
168        break;
169      case '(':             // $( -> same as GCC's { character.
170        ++LastEmitted;      // Consume '(' character.
171        if (CurVariant != -1) {
172          llvm_report_error("Nested variants found in inline asm string: '"
173                            + std::string(AsmStr) + "'");
174        }
175        CurVariant = 0;     // We're in the first variant now.
176        break;
177      case '|':
178        ++LastEmitted;  // consume '|' character.
179        if (CurVariant == -1)
180          OS << '|';       // this is gcc's behavior for | outside a variant
181        else
182          ++CurVariant;   // We're in the next variant.
183        break;
184      case ')':         // $) -> same as GCC's } char.
185        ++LastEmitted;  // consume ')' character.
186        if (CurVariant == -1)
187          OS << '}';     // this is gcc's behavior for } outside a variant
188        else
189          CurVariant = -1;
190        break;
191      }
192      if (Done) break;
193
194      bool HasCurlyBraces = false;
195      if (*LastEmitted == '{') {     // ${variable}
196        ++LastEmitted;               // Consume '{' character.
197        HasCurlyBraces = true;
198      }
199
200      // If we have ${:foo}, then this is not a real operand reference, it is a
201      // "magic" string reference, just like in .td files.  Arrange to call
202      // PrintSpecial.
203      if (HasCurlyBraces && *LastEmitted == ':') {
204        ++LastEmitted;
205        const char *StrStart = LastEmitted;
206        const char *StrEnd = strchr(StrStart, '}');
207        if (StrEnd == 0)
208          llvm_report_error(Twine("Unterminated ${:foo} operand in inline asm"
209                                  " string: '") + Twine(AsmStr) + "'");
210
211        std::string Val(StrStart, StrEnd);
212        PrintSpecial(MI, OS, Val.c_str());
213        LastEmitted = StrEnd+1;
214        break;
215      }
216
217      const char *IDStart = LastEmitted;
218      const char *IDEnd = IDStart;
219      while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;
220
221      unsigned Val;
222      if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
223        llvm_report_error("Bad $ operand number in inline asm string: '"
224                          + std::string(AsmStr) + "'");
225      LastEmitted = IDEnd;
226
227      char Modifier[2] = { 0, 0 };
228
229      if (HasCurlyBraces) {
230        // If we have curly braces, check for a modifier character.  This
231        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
232        if (*LastEmitted == ':') {
233          ++LastEmitted;    // Consume ':' character.
234          if (*LastEmitted == 0)
235            llvm_report_error("Bad ${:} expression in inline asm string: '" +
236                              std::string(AsmStr) + "'");
237
238          Modifier[0] = *LastEmitted;
239          ++LastEmitted;    // Consume modifier character.
240        }
241
242        if (*LastEmitted != '}')
243          llvm_report_error("Bad ${} expression in inline asm string: '"
244                            + std::string(AsmStr) + "'");
245        ++LastEmitted;    // Consume '}' character.
246      }
247
248      if (Val >= NumOperands-1)
249        llvm_report_error("Invalid $ operand number in inline asm string: '"
250                          + std::string(AsmStr) + "'");
251
252      // Okay, we finally have a value number.  Ask the target to print this
253      // operand!
254      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
255        unsigned OpNo = 1;
256
257        bool Error = false;
258
259        // Scan to find the machine operand number for the operand.
260        for (; Val; --Val) {
261          if (OpNo >= MI->getNumOperands()) break;
262          unsigned OpFlags = MI->getOperand(OpNo).getImm();
263          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
264        }
265
266        if (OpNo >= MI->getNumOperands()) {
267          Error = true;
268        } else {
269          unsigned OpFlags = MI->getOperand(OpNo).getImm();
270          ++OpNo;  // Skip over the ID number.
271
272          if (Modifier[0] == 'l')  // labels are target independent
273            // FIXME: What if the operand isn't an MBB, report error?
274            OS << *MI->getOperand(OpNo).getMBB()->getSymbol();
275          else {
276            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
277            if ((OpFlags & 7) == 4) {
278              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
279                                                Modifier[0] ? Modifier : 0,
280                                                OS);
281            } else {
282              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
283                                          Modifier[0] ? Modifier : 0, OS);
284            }
285          }
286        }
287        if (Error) {
288          std::string msg;
289          raw_string_ostream Msg(msg);
290          Msg << "Invalid operand found in inline asm: '" << AsmStr << "'\n";
291          MI->print(Msg);
292          llvm_report_error(Msg.str());
293        }
294      }
295      break;
296    }
297    }
298  }
299  OS << '\n' << (char)0;  // null terminate string.
300  EmitInlineAsm(OS.str());
301
302  // Emit the #NOAPP end marker.  This has to happen even if verbose-asm isn't
303  // enabled, so we use EmitRawText.
304  if (OutStreamer.hasRawTextSupport())
305    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
306                            MAI->getInlineAsmEnd());
307}
308
309
310/// PrintSpecial - Print information related to the specified machine instr
311/// that is independent of the operand, and may be independent of the instr
312/// itself.  This can be useful for portably encoding the comment character
313/// or other bits of target-specific knowledge into the asmstrings.  The
314/// syntax used is ${:comment}.  Targets can override this to add support
315/// for their own strange codes.
316void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
317                              const char *Code) const {
318  if (!strcmp(Code, "private")) {
319    OS << MAI->getPrivateGlobalPrefix();
320  } else if (!strcmp(Code, "comment")) {
321    OS << MAI->getCommentString();
322  } else if (!strcmp(Code, "uid")) {
323    // Comparing the address of MI isn't sufficient, because machineinstrs may
324    // be allocated to the same address across functions.
325
326    // If this is a new LastFn instruction, bump the counter.
327    if (LastMI != MI || LastFn != getFunctionNumber()) {
328      ++Counter;
329      LastMI = MI;
330      LastFn = getFunctionNumber();
331    }
332    OS << Counter;
333  } else {
334    std::string msg;
335    raw_string_ostream Msg(msg);
336    Msg << "Unknown special formatter '" << Code
337         << "' for machine instr: " << *MI;
338    llvm_report_error(Msg.str());
339  }
340}
341
342/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
343/// instruction, using the specified assembler variant.  Targets should
344/// override this to format as appropriate.
345bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
346                                 unsigned AsmVariant, const char *ExtraCode,
347                                 raw_ostream &O) {
348  // Target doesn't support this yet!
349  return true;
350}
351
352bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
353                                       unsigned AsmVariant,
354                                       const char *ExtraCode, raw_ostream &O) {
355  // Target doesn't support this yet!
356  return true;
357}
358
359