AsmPrinterInlineAsm.cpp revision 65eeaad91d78b2a677ca889eaff60f6d807c7030 
1//===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
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 AsmPrinter class.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "asm-printer"
15#include "llvm/InlineAsm.h"
16#include "llvm/CodeGen/AsmPrinter.h"
17#include "llvm/CodeGen/MachineBasicBlock.h"
18#include "llvm/MC/MCAsmInfo.h"
19#include "llvm/MC/MCStreamer.h"
20#include "llvm/MC/MCSymbol.h"
21#include "llvm/ADT/SmallString.h"
22#include "llvm/ADT/Twine.h"
23#include "llvm/Support/ErrorHandling.h"
24#include "llvm/Support/raw_ostream.h"
25using namespace llvm;
26
27/// EmitInlineAsm - Emit a blob of inline asm to the output streamer.
28void AsmPrinter::EmitInlineAsm(StringRef Str) const {
29  assert(!Str.empty() && "Can't emit empty inline asm block");
30
31  // If the output streamer is actually a .s file, just emit the blob textually.
32  // This is useful in case the asm parser doesn't handle something but the
33  // system assembler does.
34  if (OutStreamer.hasRawTextSupport()) {
35    OutStreamer.EmitRawText(Str);
36    return;
37  }
38
39  errs() << "Inline asm not supported by this streamer!\n";
40}
41
42
43/// EmitInlineAsm - This method formats and emits the specified machine
44/// instruction that is an inline asm.
45void AsmPrinter::EmitInlineAsm(const MachineInstr *MI) const {
46  assert(MI->isInlineAsm() && "printInlineAsm only works on inline asms");
47
48  unsigned NumOperands = MI->getNumOperands();
49
50  // Count the number of register definitions to find the asm string.
51  unsigned NumDefs = 0;
52  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
53       ++NumDefs)
54    assert(NumDefs != NumOperands-1 && "No asm string?");
55
56  assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
57
58  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
59  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
60
61  // If this asmstr is empty, just print the #APP/#NOAPP markers.
62  // These are useful to see where empty asm's wound up.
63  if (AsmStr[0] == 0) {
64    if (!OutStreamer.hasRawTextSupport()) return;
65
66    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
67                            MAI->getInlineAsmStart());
68    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
69                            MAI->getInlineAsmEnd());
70    return;
71  }
72
73  // Emit the #APP start marker.  This has to happen even if verbose-asm isn't
74  // enabled, so we use EmitRawText.
75  if (OutStreamer.hasRawTextSupport())
76    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
77                            MAI->getInlineAsmStart());
78
79  // Emit the inline asm to a temporary string so we can emit it through
80  // EmitInlineAsm.
81  SmallString<256> StringData;
82  raw_svector_ostream OS(StringData);
83
84  OS << '\t';
85
86  // The variant of the current asmprinter.
87  int AsmPrinterVariant = MAI->getAssemblerDialect();
88
89  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
90  const char *LastEmitted = AsmStr; // One past the last character emitted.
91
92  while (*LastEmitted) {
93    switch (*LastEmitted) {
94    default: {
95      // Not a special case, emit the string section literally.
96      const char *LiteralEnd = LastEmitted+1;
97      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
98             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
99        ++LiteralEnd;
100      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
101        OS.write(LastEmitted, LiteralEnd-LastEmitted);
102      LastEmitted = LiteralEnd;
103      break;
104    }
105    case '\n':
106      ++LastEmitted;   // Consume newline character.
107      OS << '\n';       // Indent code with newline.
108      break;
109    case '$': {
110      ++LastEmitted;   // Consume '$' character.
111      bool Done = true;
112
113      // Handle escapes.
114      switch (*LastEmitted) {
115      default: Done = false; break;
116      case '$':     // $$ -> $
117        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
118          OS << '$';
119        ++LastEmitted;  // Consume second '$' character.
120        break;
121      case '(':             // $( -> same as GCC's { character.
122        ++LastEmitted;      // Consume '(' character.
123        if (CurVariant != -1) {
124          llvm_report_error("Nested variants found in inline asm string: '"
125                            + std::string(AsmStr) + "'");
126        }
127        CurVariant = 0;     // We're in the first variant now.
128        break;
129      case '|':
130        ++LastEmitted;  // consume '|' character.
131        if (CurVariant == -1)
132          OS << '|';       // this is gcc's behavior for | outside a variant
133        else
134          ++CurVariant;   // We're in the next variant.
135        break;
136      case ')':         // $) -> same as GCC's } char.
137        ++LastEmitted;  // consume ')' character.
138        if (CurVariant == -1)
139          OS << '}';     // this is gcc's behavior for } outside a variant
140        else
141          CurVariant = -1;
142        break;
143      }
144      if (Done) break;
145
146      bool HasCurlyBraces = false;
147      if (*LastEmitted == '{') {     // ${variable}
148        ++LastEmitted;               // Consume '{' character.
149        HasCurlyBraces = true;
150      }
151
152      // If we have ${:foo}, then this is not a real operand reference, it is a
153      // "magic" string reference, just like in .td files.  Arrange to call
154      // PrintSpecial.
155      if (HasCurlyBraces && *LastEmitted == ':') {
156        ++LastEmitted;
157        const char *StrStart = LastEmitted;
158        const char *StrEnd = strchr(StrStart, '}');
159        if (StrEnd == 0)
160          llvm_report_error(Twine("Unterminated ${:foo} operand in inline asm"
161                                  " string: '") + Twine(AsmStr) + "'");
162
163        std::string Val(StrStart, StrEnd);
164        PrintSpecial(MI, OS, Val.c_str());
165        LastEmitted = StrEnd+1;
166        break;
167      }
168
169      const char *IDStart = LastEmitted;
170      const char *IDEnd = IDStart;
171      while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;
172
173      unsigned Val;
174      if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
175        llvm_report_error("Bad $ operand number in inline asm string: '"
176                          + std::string(AsmStr) + "'");
177      LastEmitted = IDEnd;
178
179      char Modifier[2] = { 0, 0 };
180
181      if (HasCurlyBraces) {
182        // If we have curly braces, check for a modifier character.  This
183        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
184        if (*LastEmitted == ':') {
185          ++LastEmitted;    // Consume ':' character.
186          if (*LastEmitted == 0) {
187            llvm_report_error("Bad ${:} expression in inline asm string: '"
188                              + std::string(AsmStr) + "'");
189          }
190
191          Modifier[0] = *LastEmitted;
192          ++LastEmitted;    // Consume modifier character.
193        }
194
195        if (*LastEmitted != '}') {
196          llvm_report_error("Bad ${} expression in inline asm string: '"
197                            + std::string(AsmStr) + "'");
198        }
199        ++LastEmitted;    // Consume '}' character.
200      }
201
202      if (Val >= NumOperands-1) {
203        llvm_report_error("Invalid $ operand number in inline asm string: '"
204                          + std::string(AsmStr) + "'");
205      }
206
207      // Okay, we finally have a value number.  Ask the target to print this
208      // operand!
209      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
210        unsigned OpNo = 1;
211
212        bool Error = false;
213
214        // Scan to find the machine operand number for the operand.
215        for (; Val; --Val) {
216          if (OpNo >= MI->getNumOperands()) break;
217          unsigned OpFlags = MI->getOperand(OpNo).getImm();
218          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
219        }
220
221        if (OpNo >= MI->getNumOperands()) {
222          Error = true;
223        } else {
224          unsigned OpFlags = MI->getOperand(OpNo).getImm();
225          ++OpNo;  // Skip over the ID number.
226
227          if (Modifier[0] == 'l')  // labels are target independent
228            // FIXME: What if the operand isn't an MBB, report error?
229            OS << *MI->getOperand(OpNo).getMBB()->getSymbol();
230          else {
231            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
232            if ((OpFlags & 7) == 4) {
233              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
234                                                Modifier[0] ? Modifier : 0,
235                                                OS);
236            } else {
237              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
238                                          Modifier[0] ? Modifier : 0, OS);
239            }
240          }
241        }
242        if (Error) {
243          std::string msg;
244          raw_string_ostream Msg(msg);
245          Msg << "Invalid operand found in inline asm: '" << AsmStr << "'\n";
246          MI->print(Msg);
247          llvm_report_error(Msg.str());
248        }
249      }
250      break;
251    }
252    }
253  }
254  OS << "\n";
255
256  EmitInlineAsm(OS.str());
257
258  // Emit the #NOAPP end marker.  This has to happen even if verbose-asm isn't
259  // enabled, so we use EmitRawText.
260  if (OutStreamer.hasRawTextSupport())
261    OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
262                            MAI->getInlineAsmEnd());
263}
264
265
266/// PrintSpecial - Print information related to the specified machine instr
267/// that is independent of the operand, and may be independent of the instr
268/// itself.  This can be useful for portably encoding the comment character
269/// or other bits of target-specific knowledge into the asmstrings.  The
270/// syntax used is ${:comment}.  Targets can override this to add support
271/// for their own strange codes.
272void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
273                              const char *Code) const {
274  if (!strcmp(Code, "private")) {
275    OS << MAI->getPrivateGlobalPrefix();
276  } else if (!strcmp(Code, "comment")) {
277    OS << MAI->getCommentString();
278  } else if (!strcmp(Code, "uid")) {
279    // Comparing the address of MI isn't sufficient, because machineinstrs may
280    // be allocated to the same address across functions.
281
282    // If this is a new LastFn instruction, bump the counter.
283    if (LastMI != MI || LastFn != getFunctionNumber()) {
284      ++Counter;
285      LastMI = MI;
286      LastFn = getFunctionNumber();
287    }
288    OS << Counter;
289  } else {
290    std::string msg;
291    raw_string_ostream Msg(msg);
292    Msg << "Unknown special formatter '" << Code
293         << "' for machine instr: " << *MI;
294    llvm_report_error(Msg.str());
295  }
296}
297
298/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
299/// instruction, using the specified assembler variant.  Targets should
300/// override this to format as appropriate.
301bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
302                                 unsigned AsmVariant, const char *ExtraCode,
303                                 raw_ostream &O) {
304  // Target doesn't support this yet!
305  return true;
306}
307
308bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
309                                       unsigned AsmVariant,
310                                       const char *ExtraCode, raw_ostream &O) {
311  // Target doesn't support this yet!
312  return true;
313}
314
315