AsmPrinterInlineAsm.cpp revision 885d94143d0fc02fd5c4ddf1d2a2ee74c7934bff 
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, unsigned LocCookie) 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    SrcMgr.setDiagHandler((SourceMgr::DiagHandlerTy)(intptr_t)DiagHandler,
61                          LLVMCtx.getInlineAsmDiagnosticContext(), LocCookie);
62    HasDiagHandler = true;
63  }
64
65  MemoryBuffer *Buffer;
66  if (isNullTerminated)
67    Buffer = MemoryBuffer::getMemBuffer(Str, "<inline asm>");
68  else
69    Buffer = MemoryBuffer::getMemBufferCopy(Str, "<inline asm>");
70
71  // Tell SrcMgr about this buffer, it takes ownership of the buffer.
72  SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
73
74  AsmParser Parser(SrcMgr, OutContext, OutStreamer, *MAI);
75  OwningPtr<TargetAsmParser> TAP(TM.getTarget().createAsmParser(Parser));
76  if (!TAP)
77    llvm_report_error("Inline asm not supported by this streamer because"
78                      " we don't have an asm parser for this target\n");
79  Parser.setTargetParser(*TAP.get());
80
81  // Don't implicitly switch to the text section before the asm.
82  int Res = Parser.Run(/*NoInitialTextSection*/ true,
83                       /*NoFinalize*/ true);
84  if (Res && !HasDiagHandler)
85    llvm_report_error("Error parsing inline asm\n");
86}
87
88
89/// EmitInlineAsm - This method formats and emits the specified machine
90/// instruction that is an inline asm.
91void AsmPrinter::EmitInlineAsm(const MachineInstr *MI) const {
92  assert(MI->isInlineAsm() && "printInlineAsm only works on inline asms");
93
94  unsigned NumOperands = MI->getNumOperands();
95
96  // Count the number of register definitions to find the asm string.
97  unsigned NumDefs = 0;
98  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
99       ++NumDefs)
100    assert(NumDefs != NumOperands-1 && "No asm string?");
101
102  assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
103
104  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
105  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
106
107  // If this asmstr is empty, just print the #APP/#NOAPP markers.
108  // These are useful to see where empty asm's wound up.
109  if (AsmStr[0] == 0) {
110    // Don't emit the comments if writing to a .o file.
111    if (!OutStreamer.hasRawTextSupport()) return;
112
113    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
114                            MAI->getInlineAsmStart());
115    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
116                            MAI->getInlineAsmEnd());
117    return;
118  }
119
120  // Emit the #APP start marker.  This has to happen even if verbose-asm isn't
121  // enabled, so we use EmitRawText.
122  if (OutStreamer.hasRawTextSupport())
123    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
124                            MAI->getInlineAsmStart());
125
126  // Emit the inline asm to a temporary string so we can emit it through
127  // EmitInlineAsm.
128  SmallString<256> StringData;
129  raw_svector_ostream OS(StringData);
130
131  OS << '\t';
132
133  // The variant of the current asmprinter.
134  int AsmPrinterVariant = MAI->getAssemblerDialect();
135
136  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
137  const char *LastEmitted = AsmStr; // One past the last character emitted.
138
139  while (*LastEmitted) {
140    switch (*LastEmitted) {
141    default: {
142      // Not a special case, emit the string section literally.
143      const char *LiteralEnd = LastEmitted+1;
144      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
145             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
146        ++LiteralEnd;
147      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
148        OS.write(LastEmitted, LiteralEnd-LastEmitted);
149      LastEmitted = LiteralEnd;
150      break;
151    }
152    case '\n':
153      ++LastEmitted;   // Consume newline character.
154      OS << '\n';      // Indent code with newline.
155      break;
156    case '$': {
157      ++LastEmitted;   // Consume '$' character.
158      bool Done = true;
159
160      // Handle escapes.
161      switch (*LastEmitted) {
162      default: Done = false; break;
163      case '$':     // $$ -> $
164        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
165          OS << '$';
166        ++LastEmitted;  // Consume second '$' character.
167        break;
168      case '(':             // $( -> same as GCC's { character.
169        ++LastEmitted;      // Consume '(' character.
170        if (CurVariant != -1) {
171          llvm_report_error("Nested variants found in inline asm string: '"
172                            + std::string(AsmStr) + "'");
173        }
174        CurVariant = 0;     // We're in the first variant now.
175        break;
176      case '|':
177        ++LastEmitted;  // consume '|' character.
178        if (CurVariant == -1)
179          OS << '|';       // this is gcc's behavior for | outside a variant
180        else
181          ++CurVariant;   // We're in the next variant.
182        break;
183      case ')':         // $) -> same as GCC's } char.
184        ++LastEmitted;  // consume ')' character.
185        if (CurVariant == -1)
186          OS << '}';     // this is gcc's behavior for } outside a variant
187        else
188          CurVariant = -1;
189        break;
190      }
191      if (Done) break;
192
193      bool HasCurlyBraces = false;
194      if (*LastEmitted == '{') {     // ${variable}
195        ++LastEmitted;               // Consume '{' character.
196        HasCurlyBraces = true;
197      }
198
199      // If we have ${:foo}, then this is not a real operand reference, it is a
200      // "magic" string reference, just like in .td files.  Arrange to call
201      // PrintSpecial.
202      if (HasCurlyBraces && *LastEmitted == ':') {
203        ++LastEmitted;
204        const char *StrStart = LastEmitted;
205        const char *StrEnd = strchr(StrStart, '}');
206        if (StrEnd == 0)
207          llvm_report_error(Twine("Unterminated ${:foo} operand in inline asm"
208                                  " string: '") + Twine(AsmStr) + "'");
209
210        std::string Val(StrStart, StrEnd);
211        PrintSpecial(MI, OS, Val.c_str());
212        LastEmitted = StrEnd+1;
213        break;
214      }
215
216      const char *IDStart = LastEmitted;
217      const char *IDEnd = IDStart;
218      while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;
219
220      unsigned Val;
221      if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
222        llvm_report_error("Bad $ operand number in inline asm string: '"
223                          + std::string(AsmStr) + "'");
224      LastEmitted = IDEnd;
225
226      char Modifier[2] = { 0, 0 };
227
228      if (HasCurlyBraces) {
229        // If we have curly braces, check for a modifier character.  This
230        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
231        if (*LastEmitted == ':') {
232          ++LastEmitted;    // Consume ':' character.
233          if (*LastEmitted == 0)
234            llvm_report_error("Bad ${:} expression in inline asm string: '" +
235                              std::string(AsmStr) + "'");
236
237          Modifier[0] = *LastEmitted;
238          ++LastEmitted;    // Consume modifier character.
239        }
240
241        if (*LastEmitted != '}')
242          llvm_report_error("Bad ${} expression in inline asm string: '"
243                            + std::string(AsmStr) + "'");
244        ++LastEmitted;    // Consume '}' character.
245      }
246
247      if (Val >= NumOperands-1)
248        llvm_report_error("Invalid $ operand number in inline asm string: '"
249                          + std::string(AsmStr) + "'");
250
251      // Okay, we finally have a value number.  Ask the target to print this
252      // operand!
253      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
254        unsigned OpNo = 1;
255
256        bool Error = false;
257
258        // Scan to find the machine operand number for the operand.
259        for (; Val; --Val) {
260          if (OpNo >= MI->getNumOperands()) break;
261          unsigned OpFlags = MI->getOperand(OpNo).getImm();
262          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
263        }
264
265        if (OpNo >= MI->getNumOperands()) {
266          Error = true;
267        } else {
268          unsigned OpFlags = MI->getOperand(OpNo).getImm();
269          ++OpNo;  // Skip over the ID number.
270
271          if (Modifier[0] == 'l')  // labels are target independent
272            // FIXME: What if the operand isn't an MBB, report error?
273            OS << *MI->getOperand(OpNo).getMBB()->getSymbol();
274          else {
275            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
276            if ((OpFlags & 7) == 4) {
277              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
278                                                Modifier[0] ? Modifier : 0,
279                                                OS);
280            } else {
281              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
282                                          Modifier[0] ? Modifier : 0, OS);
283            }
284          }
285        }
286        if (Error) {
287          std::string msg;
288          raw_string_ostream Msg(msg);
289          Msg << "Invalid operand found in inline asm: '" << AsmStr << "'\n";
290          MI->print(Msg);
291          llvm_report_error(Msg.str());
292        }
293      }
294      break;
295    }
296    }
297  }
298  OS << '\n' << (char)0;  // null terminate string.
299  EmitInlineAsm(OS.str(), 0/*no loc cookie*/);
300
301  // Emit the #NOAPP end marker.  This has to happen even if verbose-asm isn't
302  // enabled, so we use EmitRawText.
303  if (OutStreamer.hasRawTextSupport())
304    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
305                            MAI->getInlineAsmEnd());
306}
307
308
309/// PrintSpecial - Print information related to the specified machine instr
310/// that is independent of the operand, and may be independent of the instr
311/// itself.  This can be useful for portably encoding the comment character
312/// or other bits of target-specific knowledge into the asmstrings.  The
313/// syntax used is ${:comment}.  Targets can override this to add support
314/// for their own strange codes.
315void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
316                              const char *Code) const {
317  if (!strcmp(Code, "private")) {
318    OS << MAI->getPrivateGlobalPrefix();
319  } else if (!strcmp(Code, "comment")) {
320    OS << MAI->getCommentString();
321  } else if (!strcmp(Code, "uid")) {
322    // Comparing the address of MI isn't sufficient, because machineinstrs may
323    // be allocated to the same address across functions.
324
325    // If this is a new LastFn instruction, bump the counter.
326    if (LastMI != MI || LastFn != getFunctionNumber()) {
327      ++Counter;
328      LastMI = MI;
329      LastFn = getFunctionNumber();
330    }
331    OS << Counter;
332  } else {
333    std::string msg;
334    raw_string_ostream Msg(msg);
335    Msg << "Unknown special formatter '" << Code
336         << "' for machine instr: " << *MI;
337    llvm_report_error(Msg.str());
338  }
339}
340
341/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
342/// instruction, using the specified assembler variant.  Targets should
343/// override this to format as appropriate.
344bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
345                                 unsigned AsmVariant, const char *ExtraCode,
346                                 raw_ostream &O) {
347  // Target doesn't support this yet!
348  return true;
349}
350
351bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
352                                       unsigned AsmVariant,
353                                       const char *ExtraCode, raw_ostream &O) {
354  // Target doesn't support this yet!
355  return true;
356}
357
358