AsmPrinterInlineAsm.cpp revision 7abe37e4aee38cc79d91dd069a37d7e91d5bef53 
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/Constants.h"
17#include "llvm/InlineAsm.h"
18#include "llvm/LLVMContext.h"
19#include "llvm/Module.h"
20#include "llvm/CodeGen/MachineBasicBlock.h"
21#include "llvm/CodeGen/MachineModuleInfo.h"
22#include "llvm/MC/MCAsmInfo.h"
23#include "llvm/MC/MCStreamer.h"
24#include "llvm/MC/MCSymbol.h"
25#include "llvm/MC/MCParser/AsmParser.h"
26#include "llvm/Target/TargetAsmParser.h"
27#include "llvm/Target/TargetMachine.h"
28#include "llvm/Target/TargetRegistry.h"
29#include "llvm/ADT/OwningPtr.h"
30#include "llvm/ADT/SmallString.h"
31#include "llvm/ADT/Twine.h"
32#include "llvm/Support/ErrorHandling.h"
33#include "llvm/Support/MemoryBuffer.h"
34#include "llvm/Support/SourceMgr.h"
35#include "llvm/Support/raw_ostream.h"
36using namespace llvm;
37
38/// EmitInlineAsm - Emit a blob of inline asm to the output streamer.
39void AsmPrinter::EmitInlineAsm(StringRef Str, unsigned LocCookie) const {
40  assert(!Str.empty() && "Can't emit empty inline asm block");
41
42  // Remember if the buffer is nul terminated or not so we can avoid a copy.
43  bool isNullTerminated = Str.back() == 0;
44  if (isNullTerminated)
45    Str = Str.substr(0, Str.size()-1);
46
47  // If the output streamer is actually a .s file, just emit the blob textually.
48  // This is useful in case the asm parser doesn't handle something but the
49  // system assembler does.
50  if (OutStreamer.hasRawTextSupport()) {
51    OutStreamer.EmitRawText(Str);
52    return;
53  }
54
55  SourceMgr SrcMgr;
56
57  // If the current LLVMContext has an inline asm handler, set it in SourceMgr.
58  LLVMContext &LLVMCtx = MMI->getModule()->getContext();
59  bool HasDiagHandler = false;
60  if (void *DiagHandler = LLVMCtx.getInlineAsmDiagnosticHandler()) {
61    SrcMgr.setDiagHandler((SourceMgr::DiagHandlerTy)(intptr_t)DiagHandler,
62                          LLVMCtx.getInlineAsmDiagnosticContext(), LocCookie);
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    report_fatal_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    report_fatal_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-2 && "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  // Get the !srcloc metadata node if we have it, and decode the loc cookie from
128  // it.
129  unsigned LocCookie = 0;
130  for (unsigned i = MI->getNumOperands(); i != 0; --i) {
131    if (MI->getOperand(i-1).isMetadata())
132      if (const MDNode *SrcLoc = MI->getOperand(i-1).getMetadata())
133        if (SrcLoc->getNumOperands() != 0)
134          if (const ConstantInt *CI =
135              dyn_cast<ConstantInt>(SrcLoc->getOperand(0))) {
136            LocCookie = CI->getZExtValue();
137            break;
138          }
139  }
140
141  // Emit the inline asm to a temporary string so we can emit it through
142  // EmitInlineAsm.
143  SmallString<256> StringData;
144  raw_svector_ostream OS(StringData);
145
146  OS << '\t';
147
148  // The variant of the current asmprinter.
149  int AsmPrinterVariant = MAI->getAssemblerDialect();
150
151  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
152  const char *LastEmitted = AsmStr; // One past the last character emitted.
153
154  while (*LastEmitted) {
155    switch (*LastEmitted) {
156    default: {
157      // Not a special case, emit the string section literally.
158      const char *LiteralEnd = LastEmitted+1;
159      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
160             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
161        ++LiteralEnd;
162      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
163        OS.write(LastEmitted, LiteralEnd-LastEmitted);
164      LastEmitted = LiteralEnd;
165      break;
166    }
167    case '\n':
168      ++LastEmitted;   // Consume newline character.
169      OS << '\n';      // Indent code with newline.
170      break;
171    case '$': {
172      ++LastEmitted;   // Consume '$' character.
173      bool Done = true;
174
175      // Handle escapes.
176      switch (*LastEmitted) {
177      default: Done = false; break;
178      case '$':     // $$ -> $
179        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
180          OS << '$';
181        ++LastEmitted;  // Consume second '$' character.
182        break;
183      case '(':             // $( -> same as GCC's { character.
184        ++LastEmitted;      // Consume '(' character.
185        if (CurVariant != -1)
186          report_fatal_error("Nested variants found in inline asm string: '" +
187                             Twine(AsmStr) + "'");
188        CurVariant = 0;     // We're in the first variant now.
189        break;
190      case '|':
191        ++LastEmitted;  // consume '|' character.
192        if (CurVariant == -1)
193          OS << '|';       // this is gcc's behavior for | outside a variant
194        else
195          ++CurVariant;   // We're in the next variant.
196        break;
197      case ')':         // $) -> same as GCC's } char.
198        ++LastEmitted;  // consume ')' character.
199        if (CurVariant == -1)
200          OS << '}';     // this is gcc's behavior for } outside a variant
201        else
202          CurVariant = -1;
203        break;
204      }
205      if (Done) break;
206
207      bool HasCurlyBraces = false;
208      if (*LastEmitted == '{') {     // ${variable}
209        ++LastEmitted;               // Consume '{' character.
210        HasCurlyBraces = true;
211      }
212
213      // If we have ${:foo}, then this is not a real operand reference, it is a
214      // "magic" string reference, just like in .td files.  Arrange to call
215      // PrintSpecial.
216      if (HasCurlyBraces && *LastEmitted == ':') {
217        ++LastEmitted;
218        const char *StrStart = LastEmitted;
219        const char *StrEnd = strchr(StrStart, '}');
220        if (StrEnd == 0)
221          report_fatal_error("Unterminated ${:foo} operand in inline asm"
222                             " string: '" + Twine(AsmStr) + "'");
223
224        std::string Val(StrStart, StrEnd);
225        PrintSpecial(MI, OS, Val.c_str());
226        LastEmitted = StrEnd+1;
227        break;
228      }
229
230      const char *IDStart = LastEmitted;
231      const char *IDEnd = IDStart;
232      while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;
233
234      unsigned Val;
235      if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
236        report_fatal_error("Bad $ operand number in inline asm string: '" +
237                           Twine(AsmStr) + "'");
238      LastEmitted = IDEnd;
239
240      char Modifier[2] = { 0, 0 };
241
242      if (HasCurlyBraces) {
243        // If we have curly braces, check for a modifier character.  This
244        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
245        if (*LastEmitted == ':') {
246          ++LastEmitted;    // Consume ':' character.
247          if (*LastEmitted == 0)
248            report_fatal_error("Bad ${:} expression in inline asm string: '" +
249                               Twine(AsmStr) + "'");
250
251          Modifier[0] = *LastEmitted;
252          ++LastEmitted;    // Consume modifier character.
253        }
254
255        if (*LastEmitted != '}')
256          report_fatal_error("Bad ${} expression in inline asm string: '" +
257                             Twine(AsmStr) + "'");
258        ++LastEmitted;    // Consume '}' character.
259      }
260
261      if (Val >= NumOperands-1)
262        report_fatal_error("Invalid $ operand number in inline asm string: '" +
263                           Twine(AsmStr) + "'");
264
265      // Okay, we finally have a value number.  Ask the target to print this
266      // operand!
267      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
268        unsigned OpNo = 1;
269
270        bool Error = false;
271
272        // Scan to find the machine operand number for the operand.
273        for (; Val; --Val) {
274          if (OpNo >= MI->getNumOperands()) break;
275          unsigned OpFlags = MI->getOperand(OpNo).getImm();
276          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
277        }
278
279        if (OpNo >= MI->getNumOperands()) {
280          Error = true;
281        } else {
282          unsigned OpFlags = MI->getOperand(OpNo).getImm();
283          ++OpNo;  // Skip over the ID number.
284
285          if (Modifier[0] == 'l')  // labels are target independent
286            // FIXME: What if the operand isn't an MBB, report error?
287            OS << *MI->getOperand(OpNo).getMBB()->getSymbol();
288          else {
289            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
290            if (InlineAsm::isMemKind(OpFlags)) {
291              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
292                                                Modifier[0] ? Modifier : 0,
293                                                OS);
294            } else {
295              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
296                                          Modifier[0] ? Modifier : 0, OS);
297            }
298          }
299        }
300        if (Error) {
301          std::string msg;
302          raw_string_ostream Msg(msg);
303          Msg << "invalid operand in inline asm: '" << AsmStr << "'";
304          MMI->getModule()->getContext().emitError(LocCookie, Msg.str());
305        }
306      }
307      break;
308    }
309    }
310  }
311  OS << '\n' << (char)0;  // null terminate string.
312  EmitInlineAsm(OS.str(), LocCookie);
313
314  // Emit the #NOAPP end marker.  This has to happen even if verbose-asm isn't
315  // enabled, so we use EmitRawText.
316  if (OutStreamer.hasRawTextSupport())
317    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
318                            MAI->getInlineAsmEnd());
319}
320
321
322/// PrintSpecial - Print information related to the specified machine instr
323/// that is independent of the operand, and may be independent of the instr
324/// itself.  This can be useful for portably encoding the comment character
325/// or other bits of target-specific knowledge into the asmstrings.  The
326/// syntax used is ${:comment}.  Targets can override this to add support
327/// for their own strange codes.
328void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
329                              const char *Code) const {
330  if (!strcmp(Code, "private")) {
331    OS << MAI->getPrivateGlobalPrefix();
332  } else if (!strcmp(Code, "comment")) {
333    OS << MAI->getCommentString();
334  } else if (!strcmp(Code, "uid")) {
335    // Comparing the address of MI isn't sufficient, because machineinstrs may
336    // be allocated to the same address across functions.
337
338    // If this is a new LastFn instruction, bump the counter.
339    if (LastMI != MI || LastFn != getFunctionNumber()) {
340      ++Counter;
341      LastMI = MI;
342      LastFn = getFunctionNumber();
343    }
344    OS << Counter;
345  } else {
346    std::string msg;
347    raw_string_ostream Msg(msg);
348    Msg << "Unknown special formatter '" << Code
349         << "' for machine instr: " << *MI;
350    report_fatal_error(Msg.str());
351  }
352}
353
354/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
355/// instruction, using the specified assembler variant.  Targets should
356/// override this to format as appropriate.
357bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
358                                 unsigned AsmVariant, const char *ExtraCode,
359                                 raw_ostream &O) {
360  // Target doesn't support this yet!
361  return true;
362}
363
364bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
365                                       unsigned AsmVariant,
366                                       const char *ExtraCode, raw_ostream &O) {
367  // Target doesn't support this yet!
368  return true;
369}
370
371