AsmPrinterInlineAsm.cpp revision 1bd7335a17010bd4d8f86736cf73cac9f3fb80a5 
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  if (const MDNode *SrcLoc = MI->getOperand(NumOperands-1).getMetadata()) {
131    if (SrcLoc->getNumOperands() != 0)
132      if (const ConstantInt *CI = dyn_cast<ConstantInt>(SrcLoc->getOperand(0)))
133        LocCookie = CI->getZExtValue();
134  }
135
136  // Emit the inline asm to a temporary string so we can emit it through
137  // EmitInlineAsm.
138  SmallString<256> StringData;
139  raw_svector_ostream OS(StringData);
140
141  OS << '\t';
142
143  // The variant of the current asmprinter.
144  int AsmPrinterVariant = MAI->getAssemblerDialect();
145
146  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
147  const char *LastEmitted = AsmStr; // One past the last character emitted.
148
149  while (*LastEmitted) {
150    switch (*LastEmitted) {
151    default: {
152      // Not a special case, emit the string section literally.
153      const char *LiteralEnd = LastEmitted+1;
154      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
155             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
156        ++LiteralEnd;
157      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
158        OS.write(LastEmitted, LiteralEnd-LastEmitted);
159      LastEmitted = LiteralEnd;
160      break;
161    }
162    case '\n':
163      ++LastEmitted;   // Consume newline character.
164      OS << '\n';      // Indent code with newline.
165      break;
166    case '$': {
167      ++LastEmitted;   // Consume '$' character.
168      bool Done = true;
169
170      // Handle escapes.
171      switch (*LastEmitted) {
172      default: Done = false; break;
173      case '$':     // $$ -> $
174        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
175          OS << '$';
176        ++LastEmitted;  // Consume second '$' character.
177        break;
178      case '(':             // $( -> same as GCC's { character.
179        ++LastEmitted;      // Consume '(' character.
180        if (CurVariant != -1)
181          report_fatal_error("Nested variants found in inline asm string: '" +
182                             Twine(AsmStr) + "'");
183        CurVariant = 0;     // We're in the first variant now.
184        break;
185      case '|':
186        ++LastEmitted;  // consume '|' character.
187        if (CurVariant == -1)
188          OS << '|';       // this is gcc's behavior for | outside a variant
189        else
190          ++CurVariant;   // We're in the next variant.
191        break;
192      case ')':         // $) -> same as GCC's } char.
193        ++LastEmitted;  // consume ')' character.
194        if (CurVariant == -1)
195          OS << '}';     // this is gcc's behavior for } outside a variant
196        else
197          CurVariant = -1;
198        break;
199      }
200      if (Done) break;
201
202      bool HasCurlyBraces = false;
203      if (*LastEmitted == '{') {     // ${variable}
204        ++LastEmitted;               // Consume '{' character.
205        HasCurlyBraces = true;
206      }
207
208      // If we have ${:foo}, then this is not a real operand reference, it is a
209      // "magic" string reference, just like in .td files.  Arrange to call
210      // PrintSpecial.
211      if (HasCurlyBraces && *LastEmitted == ':') {
212        ++LastEmitted;
213        const char *StrStart = LastEmitted;
214        const char *StrEnd = strchr(StrStart, '}');
215        if (StrEnd == 0)
216          report_fatal_error("Unterminated ${:foo} operand in inline asm"
217                             " string: '" + Twine(AsmStr) + "'");
218
219        std::string Val(StrStart, StrEnd);
220        PrintSpecial(MI, OS, Val.c_str());
221        LastEmitted = StrEnd+1;
222        break;
223      }
224
225      const char *IDStart = LastEmitted;
226      const char *IDEnd = IDStart;
227      while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;
228
229      unsigned Val;
230      if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
231        report_fatal_error("Bad $ operand number in inline asm string: '" +
232                           Twine(AsmStr) + "'");
233      LastEmitted = IDEnd;
234
235      char Modifier[2] = { 0, 0 };
236
237      if (HasCurlyBraces) {
238        // If we have curly braces, check for a modifier character.  This
239        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
240        if (*LastEmitted == ':') {
241          ++LastEmitted;    // Consume ':' character.
242          if (*LastEmitted == 0)
243            report_fatal_error("Bad ${:} expression in inline asm string: '" +
244                               Twine(AsmStr) + "'");
245
246          Modifier[0] = *LastEmitted;
247          ++LastEmitted;    // Consume modifier character.
248        }
249
250        if (*LastEmitted != '}')
251          report_fatal_error("Bad ${} expression in inline asm string: '" +
252                             Twine(AsmStr) + "'");
253        ++LastEmitted;    // Consume '}' character.
254      }
255
256      if (Val >= NumOperands-1)
257        report_fatal_error("Invalid $ operand number in inline asm string: '" +
258                           Twine(AsmStr) + "'");
259
260      // Okay, we finally have a value number.  Ask the target to print this
261      // operand!
262      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
263        unsigned OpNo = 1;
264
265        bool Error = false;
266
267        // Scan to find the machine operand number for the operand.
268        for (; Val; --Val) {
269          if (OpNo >= MI->getNumOperands()) break;
270          unsigned OpFlags = MI->getOperand(OpNo).getImm();
271          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
272        }
273
274        if (OpNo >= MI->getNumOperands()) {
275          Error = true;
276        } else {
277          unsigned OpFlags = MI->getOperand(OpNo).getImm();
278          ++OpNo;  // Skip over the ID number.
279
280          if (Modifier[0] == 'l')  // labels are target independent
281            // FIXME: What if the operand isn't an MBB, report error?
282            OS << *MI->getOperand(OpNo).getMBB()->getSymbol();
283          else {
284            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
285            if (InlineAsm::isMemKind(OpFlags)) {
286              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
287                                                Modifier[0] ? Modifier : 0,
288                                                OS);
289            } else {
290              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
291                                          Modifier[0] ? Modifier : 0, OS);
292            }
293          }
294        }
295        if (Error) {
296          std::string msg;
297          raw_string_ostream Msg(msg);
298          Msg << "invalid operand in inline asm: '" << AsmStr << "'";
299          MMI->getModule()->getContext().emitError(LocCookie, Msg.str());
300        }
301      }
302      break;
303    }
304    }
305  }
306  OS << '\n' << (char)0;  // null terminate string.
307  EmitInlineAsm(OS.str(), LocCookie);
308
309  // Emit the #NOAPP end marker.  This has to happen even if verbose-asm isn't
310  // enabled, so we use EmitRawText.
311  if (OutStreamer.hasRawTextSupport())
312    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
313                            MAI->getInlineAsmEnd());
314}
315
316
317/// PrintSpecial - Print information related to the specified machine instr
318/// that is independent of the operand, and may be independent of the instr
319/// itself.  This can be useful for portably encoding the comment character
320/// or other bits of target-specific knowledge into the asmstrings.  The
321/// syntax used is ${:comment}.  Targets can override this to add support
322/// for their own strange codes.
323void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
324                              const char *Code) const {
325  if (!strcmp(Code, "private")) {
326    OS << MAI->getPrivateGlobalPrefix();
327  } else if (!strcmp(Code, "comment")) {
328    OS << MAI->getCommentString();
329  } else if (!strcmp(Code, "uid")) {
330    // Comparing the address of MI isn't sufficient, because machineinstrs may
331    // be allocated to the same address across functions.
332
333    // If this is a new LastFn instruction, bump the counter.
334    if (LastMI != MI || LastFn != getFunctionNumber()) {
335      ++Counter;
336      LastMI = MI;
337      LastFn = getFunctionNumber();
338    }
339    OS << Counter;
340  } else {
341    std::string msg;
342    raw_string_ostream Msg(msg);
343    Msg << "Unknown special formatter '" << Code
344         << "' for machine instr: " << *MI;
345    report_fatal_error(Msg.str());
346  }
347}
348
349/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
350/// instruction, using the specified assembler variant.  Targets should
351/// override this to format as appropriate.
352bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
353                                 unsigned AsmVariant, const char *ExtraCode,
354                                 raw_ostream &O) {
355  // Target doesn't support this yet!
356  return true;
357}
358
359bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
360                                       unsigned AsmVariant,
361                                       const char *ExtraCode, raw_ostream &O) {
362  // Target doesn't support this yet!
363  return true;
364}
365
366