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      1 //===--- Stmt.cpp - Statement AST Node Implementation ---------------------===//
      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 Stmt class and statement subclasses.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "clang/AST/ASTContext.h"
     15 #include "clang/AST/ASTDiagnostic.h"
     16 #include "clang/AST/ExprCXX.h"
     17 #include "clang/AST/ExprObjC.h"
     18 #include "clang/AST/ExprOpenMP.h"
     19 #include "clang/AST/Stmt.h"
     20 #include "clang/AST/StmtCXX.h"
     21 #include "clang/AST/StmtObjC.h"
     22 #include "clang/AST/StmtOpenMP.h"
     23 #include "clang/AST/Type.h"
     24 #include "clang/Basic/CharInfo.h"
     25 #include "clang/Basic/TargetInfo.h"
     26 #include "clang/Lex/Token.h"
     27 #include "llvm/ADT/StringExtras.h"
     28 #include "llvm/Support/raw_ostream.h"
     29 using namespace clang;
     30 
     31 static struct StmtClassNameTable {
     32   const char *Name;
     33   unsigned Counter;
     34   unsigned Size;
     35 } StmtClassInfo[Stmt::lastStmtConstant+1];
     36 
     37 static StmtClassNameTable &getStmtInfoTableEntry(Stmt::StmtClass E) {
     38   static bool Initialized = false;
     39   if (Initialized)
     40     return StmtClassInfo[E];
     41 
     42   // Intialize the table on the first use.
     43   Initialized = true;
     44 #define ABSTRACT_STMT(STMT)
     45 #define STMT(CLASS, PARENT) \
     46   StmtClassInfo[(unsigned)Stmt::CLASS##Class].Name = #CLASS;    \
     47   StmtClassInfo[(unsigned)Stmt::CLASS##Class].Size = sizeof(CLASS);
     48 #include "clang/AST/StmtNodes.inc"
     49 
     50   return StmtClassInfo[E];
     51 }
     52 
     53 void *Stmt::operator new(size_t bytes, const ASTContext& C,
     54                          unsigned alignment) {
     55   return ::operator new(bytes, C, alignment);
     56 }
     57 
     58 const char *Stmt::getStmtClassName() const {
     59   return getStmtInfoTableEntry((StmtClass) StmtBits.sClass).Name;
     60 }
     61 
     62 void Stmt::PrintStats() {
     63   // Ensure the table is primed.
     64   getStmtInfoTableEntry(Stmt::NullStmtClass);
     65 
     66   unsigned sum = 0;
     67   llvm::errs() << "\n*** Stmt/Expr Stats:\n";
     68   for (int i = 0; i != Stmt::lastStmtConstant+1; i++) {
     69     if (StmtClassInfo[i].Name == nullptr) continue;
     70     sum += StmtClassInfo[i].Counter;
     71   }
     72   llvm::errs() << "  " << sum << " stmts/exprs total.\n";
     73   sum = 0;
     74   for (int i = 0; i != Stmt::lastStmtConstant+1; i++) {
     75     if (StmtClassInfo[i].Name == nullptr) continue;
     76     if (StmtClassInfo[i].Counter == 0) continue;
     77     llvm::errs() << "    " << StmtClassInfo[i].Counter << " "
     78                  << StmtClassInfo[i].Name << ", " << StmtClassInfo[i].Size
     79                  << " each (" << StmtClassInfo[i].Counter*StmtClassInfo[i].Size
     80                  << " bytes)\n";
     81     sum += StmtClassInfo[i].Counter*StmtClassInfo[i].Size;
     82   }
     83 
     84   llvm::errs() << "Total bytes = " << sum << "\n";
     85 }
     86 
     87 void Stmt::addStmtClass(StmtClass s) {
     88   ++getStmtInfoTableEntry(s).Counter;
     89 }
     90 
     91 bool Stmt::StatisticsEnabled = false;
     92 void Stmt::EnableStatistics() {
     93   StatisticsEnabled = true;
     94 }
     95 
     96 Stmt *Stmt::IgnoreImplicit() {
     97   Stmt *s = this;
     98 
     99   if (auto *ewc = dyn_cast<ExprWithCleanups>(s))
    100     s = ewc->getSubExpr();
    101 
    102   if (auto *mte = dyn_cast<MaterializeTemporaryExpr>(s))
    103     s = mte->GetTemporaryExpr();
    104 
    105   if (auto *bte = dyn_cast<CXXBindTemporaryExpr>(s))
    106     s = bte->getSubExpr();
    107 
    108   while (auto *ice = dyn_cast<ImplicitCastExpr>(s))
    109     s = ice->getSubExpr();
    110 
    111   return s;
    112 }
    113 
    114 /// \brief Skip no-op (attributed, compound) container stmts and skip captured
    115 /// stmt at the top, if \a IgnoreCaptured is true.
    116 Stmt *Stmt::IgnoreContainers(bool IgnoreCaptured) {
    117   Stmt *S = this;
    118   if (IgnoreCaptured)
    119     if (auto CapS = dyn_cast_or_null<CapturedStmt>(S))
    120       S = CapS->getCapturedStmt();
    121   while (true) {
    122     if (auto AS = dyn_cast_or_null<AttributedStmt>(S))
    123       S = AS->getSubStmt();
    124     else if (auto CS = dyn_cast_or_null<CompoundStmt>(S)) {
    125       if (CS->size() != 1)
    126         break;
    127       S = CS->body_back();
    128     } else
    129       break;
    130   }
    131   return S;
    132 }
    133 
    134 /// \brief Strip off all label-like statements.
    135 ///
    136 /// This will strip off label statements, case statements, attributed
    137 /// statements and default statements recursively.
    138 const Stmt *Stmt::stripLabelLikeStatements() const {
    139   const Stmt *S = this;
    140   while (true) {
    141     if (const LabelStmt *LS = dyn_cast<LabelStmt>(S))
    142       S = LS->getSubStmt();
    143     else if (const SwitchCase *SC = dyn_cast<SwitchCase>(S))
    144       S = SC->getSubStmt();
    145     else if (const AttributedStmt *AS = dyn_cast<AttributedStmt>(S))
    146       S = AS->getSubStmt();
    147     else
    148       return S;
    149   }
    150 }
    151 
    152 namespace {
    153   struct good {};
    154   struct bad {};
    155 
    156   // These silly little functions have to be static inline to suppress
    157   // unused warnings, and they have to be defined to suppress other
    158   // warnings.
    159   static inline good is_good(good) { return good(); }
    160 
    161   typedef Stmt::child_range children_t();
    162   template <class T> good implements_children(children_t T::*) {
    163     return good();
    164   }
    165   LLVM_ATTRIBUTE_UNUSED
    166   static inline bad implements_children(children_t Stmt::*) {
    167     return bad();
    168   }
    169 
    170   typedef SourceLocation getLocStart_t() const;
    171   template <class T> good implements_getLocStart(getLocStart_t T::*) {
    172     return good();
    173   }
    174   LLVM_ATTRIBUTE_UNUSED
    175   static inline bad implements_getLocStart(getLocStart_t Stmt::*) {
    176     return bad();
    177   }
    178 
    179   typedef SourceLocation getLocEnd_t() const;
    180   template <class T> good implements_getLocEnd(getLocEnd_t T::*) {
    181     return good();
    182   }
    183   LLVM_ATTRIBUTE_UNUSED
    184   static inline bad implements_getLocEnd(getLocEnd_t Stmt::*) {
    185     return bad();
    186   }
    187 
    188 #define ASSERT_IMPLEMENTS_children(type) \
    189   (void) is_good(implements_children(&type::children))
    190 #define ASSERT_IMPLEMENTS_getLocStart(type) \
    191   (void) is_good(implements_getLocStart(&type::getLocStart))
    192 #define ASSERT_IMPLEMENTS_getLocEnd(type) \
    193   (void) is_good(implements_getLocEnd(&type::getLocEnd))
    194 }
    195 
    196 /// Check whether the various Stmt classes implement their member
    197 /// functions.
    198 LLVM_ATTRIBUTE_UNUSED
    199 static inline void check_implementations() {
    200 #define ABSTRACT_STMT(type)
    201 #define STMT(type, base) \
    202   ASSERT_IMPLEMENTS_children(type); \
    203   ASSERT_IMPLEMENTS_getLocStart(type); \
    204   ASSERT_IMPLEMENTS_getLocEnd(type);
    205 #include "clang/AST/StmtNodes.inc"
    206 }
    207 
    208 Stmt::child_range Stmt::children() {
    209   switch (getStmtClass()) {
    210   case Stmt::NoStmtClass: llvm_unreachable("statement without class");
    211 #define ABSTRACT_STMT(type)
    212 #define STMT(type, base) \
    213   case Stmt::type##Class: \
    214     return static_cast<type*>(this)->children();
    215 #include "clang/AST/StmtNodes.inc"
    216   }
    217   llvm_unreachable("unknown statement kind!");
    218 }
    219 
    220 // Amusing macro metaprogramming hack: check whether a class provides
    221 // a more specific implementation of getSourceRange.
    222 //
    223 // See also Expr.cpp:getExprLoc().
    224 namespace {
    225   /// This implementation is used when a class provides a custom
    226   /// implementation of getSourceRange.
    227   template <class S, class T>
    228   SourceRange getSourceRangeImpl(const Stmt *stmt,
    229                                  SourceRange (T::*v)() const) {
    230     return static_cast<const S*>(stmt)->getSourceRange();
    231   }
    232 
    233   /// This implementation is used when a class doesn't provide a custom
    234   /// implementation of getSourceRange.  Overload resolution should pick it over
    235   /// the implementation above because it's more specialized according to
    236   /// function template partial ordering.
    237   template <class S>
    238   SourceRange getSourceRangeImpl(const Stmt *stmt,
    239                                  SourceRange (Stmt::*v)() const) {
    240     return SourceRange(static_cast<const S*>(stmt)->getLocStart(),
    241                        static_cast<const S*>(stmt)->getLocEnd());
    242   }
    243 }
    244 
    245 SourceRange Stmt::getSourceRange() const {
    246   switch (getStmtClass()) {
    247   case Stmt::NoStmtClass: llvm_unreachable("statement without class");
    248 #define ABSTRACT_STMT(type)
    249 #define STMT(type, base) \
    250   case Stmt::type##Class: \
    251     return getSourceRangeImpl<type>(this, &type::getSourceRange);
    252 #include "clang/AST/StmtNodes.inc"
    253   }
    254   llvm_unreachable("unknown statement kind!");
    255 }
    256 
    257 SourceLocation Stmt::getLocStart() const {
    258 //  llvm::errs() << "getLocStart() for " << getStmtClassName() << "\n";
    259   switch (getStmtClass()) {
    260   case Stmt::NoStmtClass: llvm_unreachable("statement without class");
    261 #define ABSTRACT_STMT(type)
    262 #define STMT(type, base) \
    263   case Stmt::type##Class: \
    264     return static_cast<const type*>(this)->getLocStart();
    265 #include "clang/AST/StmtNodes.inc"
    266   }
    267   llvm_unreachable("unknown statement kind");
    268 }
    269 
    270 SourceLocation Stmt::getLocEnd() const {
    271   switch (getStmtClass()) {
    272   case Stmt::NoStmtClass: llvm_unreachable("statement without class");
    273 #define ABSTRACT_STMT(type)
    274 #define STMT(type, base) \
    275   case Stmt::type##Class: \
    276     return static_cast<const type*>(this)->getLocEnd();
    277 #include "clang/AST/StmtNodes.inc"
    278   }
    279   llvm_unreachable("unknown statement kind");
    280 }
    281 
    282 CompoundStmt::CompoundStmt(const ASTContext &C, ArrayRef<Stmt*> Stmts,
    283                            SourceLocation LB, SourceLocation RB)
    284   : Stmt(CompoundStmtClass), LBraceLoc(LB), RBraceLoc(RB) {
    285   CompoundStmtBits.NumStmts = Stmts.size();
    286   assert(CompoundStmtBits.NumStmts == Stmts.size() &&
    287          "NumStmts doesn't fit in bits of CompoundStmtBits.NumStmts!");
    288 
    289   if (Stmts.size() == 0) {
    290     Body = nullptr;
    291     return;
    292   }
    293 
    294   Body = new (C) Stmt*[Stmts.size()];
    295   std::copy(Stmts.begin(), Stmts.end(), Body);
    296 }
    297 
    298 void CompoundStmt::setStmts(const ASTContext &C, ArrayRef<Stmt *> Stmts) {
    299   if (Body)
    300     C.Deallocate(Body);
    301   CompoundStmtBits.NumStmts = Stmts.size();
    302   assert(CompoundStmtBits.NumStmts == Stmts.size() &&
    303          "NumStmts doesn't fit in bits of CompoundStmtBits.NumStmts!");
    304 
    305   Body = new (C) Stmt*[Stmts.size()];
    306   std::copy(Stmts.begin(), Stmts.end(), Body);
    307 }
    308 
    309 const char *LabelStmt::getName() const {
    310   return getDecl()->getIdentifier()->getNameStart();
    311 }
    312 
    313 AttributedStmt *AttributedStmt::Create(const ASTContext &C, SourceLocation Loc,
    314                                        ArrayRef<const Attr*> Attrs,
    315                                        Stmt *SubStmt) {
    316   assert(!Attrs.empty() && "Attrs should not be empty");
    317   void *Mem = C.Allocate(sizeof(AttributedStmt) + sizeof(Attr *) * Attrs.size(),
    318                          llvm::alignOf<AttributedStmt>());
    319   return new (Mem) AttributedStmt(Loc, Attrs, SubStmt);
    320 }
    321 
    322 AttributedStmt *AttributedStmt::CreateEmpty(const ASTContext &C,
    323                                             unsigned NumAttrs) {
    324   assert(NumAttrs > 0 && "NumAttrs should be greater than zero");
    325   void *Mem = C.Allocate(sizeof(AttributedStmt) + sizeof(Attr *) * NumAttrs,
    326                          llvm::alignOf<AttributedStmt>());
    327   return new (Mem) AttributedStmt(EmptyShell(), NumAttrs);
    328 }
    329 
    330 std::string AsmStmt::generateAsmString(const ASTContext &C) const {
    331   if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(this))
    332     return gccAsmStmt->generateAsmString(C);
    333   if (const MSAsmStmt *msAsmStmt = dyn_cast<MSAsmStmt>(this))
    334     return msAsmStmt->generateAsmString(C);
    335   llvm_unreachable("unknown asm statement kind!");
    336 }
    337 
    338 StringRef AsmStmt::getOutputConstraint(unsigned i) const {
    339   if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(this))
    340     return gccAsmStmt->getOutputConstraint(i);
    341   if (const MSAsmStmt *msAsmStmt = dyn_cast<MSAsmStmt>(this))
    342     return msAsmStmt->getOutputConstraint(i);
    343   llvm_unreachable("unknown asm statement kind!");
    344 }
    345 
    346 const Expr *AsmStmt::getOutputExpr(unsigned i) const {
    347   if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(this))
    348     return gccAsmStmt->getOutputExpr(i);
    349   if (const MSAsmStmt *msAsmStmt = dyn_cast<MSAsmStmt>(this))
    350     return msAsmStmt->getOutputExpr(i);
    351   llvm_unreachable("unknown asm statement kind!");
    352 }
    353 
    354 StringRef AsmStmt::getInputConstraint(unsigned i) const {
    355   if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(this))
    356     return gccAsmStmt->getInputConstraint(i);
    357   if (const MSAsmStmt *msAsmStmt = dyn_cast<MSAsmStmt>(this))
    358     return msAsmStmt->getInputConstraint(i);
    359   llvm_unreachable("unknown asm statement kind!");
    360 }
    361 
    362 const Expr *AsmStmt::getInputExpr(unsigned i) const {
    363   if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(this))
    364     return gccAsmStmt->getInputExpr(i);
    365   if (const MSAsmStmt *msAsmStmt = dyn_cast<MSAsmStmt>(this))
    366     return msAsmStmt->getInputExpr(i);
    367   llvm_unreachable("unknown asm statement kind!");
    368 }
    369 
    370 StringRef AsmStmt::getClobber(unsigned i) const {
    371   if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(this))
    372     return gccAsmStmt->getClobber(i);
    373   if (const MSAsmStmt *msAsmStmt = dyn_cast<MSAsmStmt>(this))
    374     return msAsmStmt->getClobber(i);
    375   llvm_unreachable("unknown asm statement kind!");
    376 }
    377 
    378 /// getNumPlusOperands - Return the number of output operands that have a "+"
    379 /// constraint.
    380 unsigned AsmStmt::getNumPlusOperands() const {
    381   unsigned Res = 0;
    382   for (unsigned i = 0, e = getNumOutputs(); i != e; ++i)
    383     if (isOutputPlusConstraint(i))
    384       ++Res;
    385   return Res;
    386 }
    387 
    388 char GCCAsmStmt::AsmStringPiece::getModifier() const {
    389   assert(isOperand() && "Only Operands can have modifiers.");
    390   return isLetter(Str[0]) ? Str[0] : '\0';
    391 }
    392 
    393 StringRef GCCAsmStmt::getClobber(unsigned i) const {
    394   return getClobberStringLiteral(i)->getString();
    395 }
    396 
    397 Expr *GCCAsmStmt::getOutputExpr(unsigned i) {
    398   return cast<Expr>(Exprs[i]);
    399 }
    400 
    401 /// getOutputConstraint - Return the constraint string for the specified
    402 /// output operand.  All output constraints are known to be non-empty (either
    403 /// '=' or '+').
    404 StringRef GCCAsmStmt::getOutputConstraint(unsigned i) const {
    405   return getOutputConstraintLiteral(i)->getString();
    406 }
    407 
    408 Expr *GCCAsmStmt::getInputExpr(unsigned i) {
    409   return cast<Expr>(Exprs[i + NumOutputs]);
    410 }
    411 void GCCAsmStmt::setInputExpr(unsigned i, Expr *E) {
    412   Exprs[i + NumOutputs] = E;
    413 }
    414 
    415 /// getInputConstraint - Return the specified input constraint.  Unlike output
    416 /// constraints, these can be empty.
    417 StringRef GCCAsmStmt::getInputConstraint(unsigned i) const {
    418   return getInputConstraintLiteral(i)->getString();
    419 }
    420 
    421 void GCCAsmStmt::setOutputsAndInputsAndClobbers(const ASTContext &C,
    422                                                 IdentifierInfo **Names,
    423                                                 StringLiteral **Constraints,
    424                                                 Stmt **Exprs,
    425                                                 unsigned NumOutputs,
    426                                                 unsigned NumInputs,
    427                                                 StringLiteral **Clobbers,
    428                                                 unsigned NumClobbers) {
    429   this->NumOutputs = NumOutputs;
    430   this->NumInputs = NumInputs;
    431   this->NumClobbers = NumClobbers;
    432 
    433   unsigned NumExprs = NumOutputs + NumInputs;
    434 
    435   C.Deallocate(this->Names);
    436   this->Names = new (C) IdentifierInfo*[NumExprs];
    437   std::copy(Names, Names + NumExprs, this->Names);
    438 
    439   C.Deallocate(this->Exprs);
    440   this->Exprs = new (C) Stmt*[NumExprs];
    441   std::copy(Exprs, Exprs + NumExprs, this->Exprs);
    442 
    443   C.Deallocate(this->Constraints);
    444   this->Constraints = new (C) StringLiteral*[NumExprs];
    445   std::copy(Constraints, Constraints + NumExprs, this->Constraints);
    446 
    447   C.Deallocate(this->Clobbers);
    448   this->Clobbers = new (C) StringLiteral*[NumClobbers];
    449   std::copy(Clobbers, Clobbers + NumClobbers, this->Clobbers);
    450 }
    451 
    452 /// getNamedOperand - Given a symbolic operand reference like %[foo],
    453 /// translate this into a numeric value needed to reference the same operand.
    454 /// This returns -1 if the operand name is invalid.
    455 int GCCAsmStmt::getNamedOperand(StringRef SymbolicName) const {
    456   unsigned NumPlusOperands = 0;
    457 
    458   // Check if this is an output operand.
    459   for (unsigned i = 0, e = getNumOutputs(); i != e; ++i) {
    460     if (getOutputName(i) == SymbolicName)
    461       return i;
    462   }
    463 
    464   for (unsigned i = 0, e = getNumInputs(); i != e; ++i)
    465     if (getInputName(i) == SymbolicName)
    466       return getNumOutputs() + NumPlusOperands + i;
    467 
    468   // Not found.
    469   return -1;
    470 }
    471 
    472 /// AnalyzeAsmString - Analyze the asm string of the current asm, decomposing
    473 /// it into pieces.  If the asm string is erroneous, emit errors and return
    474 /// true, otherwise return false.
    475 unsigned GCCAsmStmt::AnalyzeAsmString(SmallVectorImpl<AsmStringPiece>&Pieces,
    476                                 const ASTContext &C, unsigned &DiagOffs) const {
    477   StringRef Str = getAsmString()->getString();
    478   const char *StrStart = Str.begin();
    479   const char *StrEnd = Str.end();
    480   const char *CurPtr = StrStart;
    481 
    482   // "Simple" inline asms have no constraints or operands, just convert the asm
    483   // string to escape $'s.
    484   if (isSimple()) {
    485     std::string Result;
    486     for (; CurPtr != StrEnd; ++CurPtr) {
    487       switch (*CurPtr) {
    488       case '$':
    489         Result += "$$";
    490         break;
    491       default:
    492         Result += *CurPtr;
    493         break;
    494       }
    495     }
    496     Pieces.push_back(AsmStringPiece(Result));
    497     return 0;
    498   }
    499 
    500   // CurStringPiece - The current string that we are building up as we scan the
    501   // asm string.
    502   std::string CurStringPiece;
    503 
    504   bool HasVariants = !C.getTargetInfo().hasNoAsmVariants();
    505 
    506   while (1) {
    507     // Done with the string?
    508     if (CurPtr == StrEnd) {
    509       if (!CurStringPiece.empty())
    510         Pieces.push_back(AsmStringPiece(CurStringPiece));
    511       return 0;
    512     }
    513 
    514     char CurChar = *CurPtr++;
    515     switch (CurChar) {
    516     case '$': CurStringPiece += "$$"; continue;
    517     case '{': CurStringPiece += (HasVariants ? "$(" : "{"); continue;
    518     case '|': CurStringPiece += (HasVariants ? "$|" : "|"); continue;
    519     case '}': CurStringPiece += (HasVariants ? "$)" : "}"); continue;
    520     case '%':
    521       break;
    522     default:
    523       CurStringPiece += CurChar;
    524       continue;
    525     }
    526 
    527     // Escaped "%" character in asm string.
    528     if (CurPtr == StrEnd) {
    529       // % at end of string is invalid (no escape).
    530       DiagOffs = CurPtr-StrStart-1;
    531       return diag::err_asm_invalid_escape;
    532     }
    533 
    534     char EscapedChar = *CurPtr++;
    535     if (EscapedChar == '%') {  // %% -> %
    536       // Escaped percentage sign.
    537       CurStringPiece += '%';
    538       continue;
    539     }
    540 
    541     if (EscapedChar == '=') {  // %= -> Generate an unique ID.
    542       CurStringPiece += "${:uid}";
    543       continue;
    544     }
    545 
    546     // Otherwise, we have an operand.  If we have accumulated a string so far,
    547     // add it to the Pieces list.
    548     if (!CurStringPiece.empty()) {
    549       Pieces.push_back(AsmStringPiece(CurStringPiece));
    550       CurStringPiece.clear();
    551     }
    552 
    553     // Handle operands that have asmSymbolicName (e.g., %x[foo]) and those that
    554     // don't (e.g., %x4). 'x' following the '%' is the constraint modifier.
    555 
    556     const char *Begin = CurPtr - 1; // Points to the character following '%'.
    557     const char *Percent = Begin - 1; // Points to '%'.
    558 
    559     if (isLetter(EscapedChar)) {
    560       if (CurPtr == StrEnd) { // Premature end.
    561         DiagOffs = CurPtr-StrStart-1;
    562         return diag::err_asm_invalid_escape;
    563       }
    564       EscapedChar = *CurPtr++;
    565     }
    566 
    567     const TargetInfo &TI = C.getTargetInfo();
    568     const SourceManager &SM = C.getSourceManager();
    569     const LangOptions &LO = C.getLangOpts();
    570 
    571     // Handle operands that don't have asmSymbolicName (e.g., %x4).
    572     if (isDigit(EscapedChar)) {
    573       // %n - Assembler operand n
    574       unsigned N = 0;
    575 
    576       --CurPtr;
    577       while (CurPtr != StrEnd && isDigit(*CurPtr))
    578         N = N*10 + ((*CurPtr++)-'0');
    579 
    580       unsigned NumOperands =
    581         getNumOutputs() + getNumPlusOperands() + getNumInputs();
    582       if (N >= NumOperands) {
    583         DiagOffs = CurPtr-StrStart-1;
    584         return diag::err_asm_invalid_operand_number;
    585       }
    586 
    587       // Str contains "x4" (Operand without the leading %).
    588       std::string Str(Begin, CurPtr - Begin);
    589 
    590       // (BeginLoc, EndLoc) represents the range of the operand we are currently
    591       // processing. Unlike Str, the range includes the leading '%'.
    592       SourceLocation BeginLoc =
    593           getAsmString()->getLocationOfByte(Percent - StrStart, SM, LO, TI);
    594       SourceLocation EndLoc =
    595           getAsmString()->getLocationOfByte(CurPtr - StrStart, SM, LO, TI);
    596 
    597       Pieces.emplace_back(N, std::move(Str), BeginLoc, EndLoc);
    598       continue;
    599     }
    600 
    601     // Handle operands that have asmSymbolicName (e.g., %x[foo]).
    602     if (EscapedChar == '[') {
    603       DiagOffs = CurPtr-StrStart-1;
    604 
    605       // Find the ']'.
    606       const char *NameEnd = (const char*)memchr(CurPtr, ']', StrEnd-CurPtr);
    607       if (NameEnd == nullptr)
    608         return diag::err_asm_unterminated_symbolic_operand_name;
    609       if (NameEnd == CurPtr)
    610         return diag::err_asm_empty_symbolic_operand_name;
    611 
    612       StringRef SymbolicName(CurPtr, NameEnd - CurPtr);
    613 
    614       int N = getNamedOperand(SymbolicName);
    615       if (N == -1) {
    616         // Verify that an operand with that name exists.
    617         DiagOffs = CurPtr-StrStart;
    618         return diag::err_asm_unknown_symbolic_operand_name;
    619       }
    620 
    621       // Str contains "x[foo]" (Operand without the leading %).
    622       std::string Str(Begin, NameEnd + 1 - Begin);
    623 
    624       // (BeginLoc, EndLoc) represents the range of the operand we are currently
    625       // processing. Unlike Str, the range includes the leading '%'.
    626       SourceLocation BeginLoc =
    627           getAsmString()->getLocationOfByte(Percent - StrStart, SM, LO, TI);
    628       SourceLocation EndLoc =
    629           getAsmString()->getLocationOfByte(NameEnd + 1 - StrStart, SM, LO, TI);
    630 
    631       Pieces.emplace_back(N, std::move(Str), BeginLoc, EndLoc);
    632 
    633       CurPtr = NameEnd+1;
    634       continue;
    635     }
    636 
    637     DiagOffs = CurPtr-StrStart-1;
    638     return diag::err_asm_invalid_escape;
    639   }
    640 }
    641 
    642 /// Assemble final IR asm string (GCC-style).
    643 std::string GCCAsmStmt::generateAsmString(const ASTContext &C) const {
    644   // Analyze the asm string to decompose it into its pieces.  We know that Sema
    645   // has already done this, so it is guaranteed to be successful.
    646   SmallVector<GCCAsmStmt::AsmStringPiece, 4> Pieces;
    647   unsigned DiagOffs;
    648   AnalyzeAsmString(Pieces, C, DiagOffs);
    649 
    650   std::string AsmString;
    651   for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
    652     if (Pieces[i].isString())
    653       AsmString += Pieces[i].getString();
    654     else if (Pieces[i].getModifier() == '\0')
    655       AsmString += '$' + llvm::utostr(Pieces[i].getOperandNo());
    656     else
    657       AsmString += "${" + llvm::utostr(Pieces[i].getOperandNo()) + ':' +
    658                    Pieces[i].getModifier() + '}';
    659   }
    660   return AsmString;
    661 }
    662 
    663 /// Assemble final IR asm string (MS-style).
    664 std::string MSAsmStmt::generateAsmString(const ASTContext &C) const {
    665   // FIXME: This needs to be translated into the IR string representation.
    666   return AsmStr;
    667 }
    668 
    669 Expr *MSAsmStmt::getOutputExpr(unsigned i) {
    670   return cast<Expr>(Exprs[i]);
    671 }
    672 
    673 Expr *MSAsmStmt::getInputExpr(unsigned i) {
    674   return cast<Expr>(Exprs[i + NumOutputs]);
    675 }
    676 void MSAsmStmt::setInputExpr(unsigned i, Expr *E) {
    677   Exprs[i + NumOutputs] = E;
    678 }
    679 
    680 //===----------------------------------------------------------------------===//
    681 // Constructors
    682 //===----------------------------------------------------------------------===//
    683 
    684 GCCAsmStmt::GCCAsmStmt(const ASTContext &C, SourceLocation asmloc,
    685                        bool issimple, bool isvolatile, unsigned numoutputs,
    686                        unsigned numinputs, IdentifierInfo **names,
    687                        StringLiteral **constraints, Expr **exprs,
    688                        StringLiteral *asmstr, unsigned numclobbers,
    689                        StringLiteral **clobbers, SourceLocation rparenloc)
    690   : AsmStmt(GCCAsmStmtClass, asmloc, issimple, isvolatile, numoutputs,
    691             numinputs, numclobbers), RParenLoc(rparenloc), AsmStr(asmstr) {
    692 
    693   unsigned NumExprs = NumOutputs + NumInputs;
    694 
    695   Names = new (C) IdentifierInfo*[NumExprs];
    696   std::copy(names, names + NumExprs, Names);
    697 
    698   Exprs = new (C) Stmt*[NumExprs];
    699   std::copy(exprs, exprs + NumExprs, Exprs);
    700 
    701   Constraints = new (C) StringLiteral*[NumExprs];
    702   std::copy(constraints, constraints + NumExprs, Constraints);
    703 
    704   Clobbers = new (C) StringLiteral*[NumClobbers];
    705   std::copy(clobbers, clobbers + NumClobbers, Clobbers);
    706 }
    707 
    708 MSAsmStmt::MSAsmStmt(const ASTContext &C, SourceLocation asmloc,
    709                      SourceLocation lbraceloc, bool issimple, bool isvolatile,
    710                      ArrayRef<Token> asmtoks, unsigned numoutputs,
    711                      unsigned numinputs,
    712                      ArrayRef<StringRef> constraints, ArrayRef<Expr*> exprs,
    713                      StringRef asmstr, ArrayRef<StringRef> clobbers,
    714                      SourceLocation endloc)
    715   : AsmStmt(MSAsmStmtClass, asmloc, issimple, isvolatile, numoutputs,
    716             numinputs, clobbers.size()), LBraceLoc(lbraceloc),
    717             EndLoc(endloc), NumAsmToks(asmtoks.size()) {
    718 
    719   initialize(C, asmstr, asmtoks, constraints, exprs, clobbers);
    720 }
    721 
    722 static StringRef copyIntoContext(const ASTContext &C, StringRef str) {
    723   return str.copy(C);
    724 }
    725 
    726 void MSAsmStmt::initialize(const ASTContext &C, StringRef asmstr,
    727                            ArrayRef<Token> asmtoks,
    728                            ArrayRef<StringRef> constraints,
    729                            ArrayRef<Expr*> exprs,
    730                            ArrayRef<StringRef> clobbers) {
    731   assert(NumAsmToks == asmtoks.size());
    732   assert(NumClobbers == clobbers.size());
    733 
    734   assert(exprs.size() == NumOutputs + NumInputs);
    735   assert(exprs.size() == constraints.size());
    736 
    737   AsmStr = copyIntoContext(C, asmstr);
    738 
    739   Exprs = new (C) Stmt*[exprs.size()];
    740   std::copy(exprs.begin(), exprs.end(), Exprs);
    741 
    742   AsmToks = new (C) Token[asmtoks.size()];
    743   std::copy(asmtoks.begin(), asmtoks.end(), AsmToks);
    744 
    745   Constraints = new (C) StringRef[exprs.size()];
    746   std::transform(constraints.begin(), constraints.end(), Constraints,
    747                  [&](StringRef Constraint) {
    748                    return copyIntoContext(C, Constraint);
    749                  });
    750 
    751   Clobbers = new (C) StringRef[NumClobbers];
    752   // FIXME: Avoid the allocation/copy if at all possible.
    753   std::transform(clobbers.begin(), clobbers.end(), Clobbers,
    754                  [&](StringRef Clobber) {
    755                    return copyIntoContext(C, Clobber);
    756                  });
    757 }
    758 
    759 IfStmt::IfStmt(const ASTContext &C, SourceLocation IL, VarDecl *var, Expr *cond,
    760                Stmt *then, SourceLocation EL, Stmt *elsev)
    761   : Stmt(IfStmtClass), IfLoc(IL), ElseLoc(EL)
    762 {
    763   setConditionVariable(C, var);
    764   SubExprs[COND] = cond;
    765   SubExprs[THEN] = then;
    766   SubExprs[ELSE] = elsev;
    767 }
    768 
    769 VarDecl *IfStmt::getConditionVariable() const {
    770   if (!SubExprs[VAR])
    771     return nullptr;
    772 
    773   DeclStmt *DS = cast<DeclStmt>(SubExprs[VAR]);
    774   return cast<VarDecl>(DS->getSingleDecl());
    775 }
    776 
    777 void IfStmt::setConditionVariable(const ASTContext &C, VarDecl *V) {
    778   if (!V) {
    779     SubExprs[VAR] = nullptr;
    780     return;
    781   }
    782 
    783   SourceRange VarRange = V->getSourceRange();
    784   SubExprs[VAR] = new (C) DeclStmt(DeclGroupRef(V), VarRange.getBegin(),
    785                                    VarRange.getEnd());
    786 }
    787 
    788 ForStmt::ForStmt(const ASTContext &C, Stmt *Init, Expr *Cond, VarDecl *condVar,
    789                  Expr *Inc, Stmt *Body, SourceLocation FL, SourceLocation LP,
    790                  SourceLocation RP)
    791   : Stmt(ForStmtClass), ForLoc(FL), LParenLoc(LP), RParenLoc(RP)
    792 {
    793   SubExprs[INIT] = Init;
    794   setConditionVariable(C, condVar);
    795   SubExprs[COND] = Cond;
    796   SubExprs[INC] = Inc;
    797   SubExprs[BODY] = Body;
    798 }
    799 
    800 VarDecl *ForStmt::getConditionVariable() const {
    801   if (!SubExprs[CONDVAR])
    802     return nullptr;
    803 
    804   DeclStmt *DS = cast<DeclStmt>(SubExprs[CONDVAR]);
    805   return cast<VarDecl>(DS->getSingleDecl());
    806 }
    807 
    808 void ForStmt::setConditionVariable(const ASTContext &C, VarDecl *V) {
    809   if (!V) {
    810     SubExprs[CONDVAR] = nullptr;
    811     return;
    812   }
    813 
    814   SourceRange VarRange = V->getSourceRange();
    815   SubExprs[CONDVAR] = new (C) DeclStmt(DeclGroupRef(V), VarRange.getBegin(),
    816                                        VarRange.getEnd());
    817 }
    818 
    819 SwitchStmt::SwitchStmt(const ASTContext &C, VarDecl *Var, Expr *cond)
    820     : Stmt(SwitchStmtClass), FirstCase(nullptr, false) {
    821   setConditionVariable(C, Var);
    822   SubExprs[COND] = cond;
    823   SubExprs[BODY] = nullptr;
    824 }
    825 
    826 VarDecl *SwitchStmt::getConditionVariable() const {
    827   if (!SubExprs[VAR])
    828     return nullptr;
    829 
    830   DeclStmt *DS = cast<DeclStmt>(SubExprs[VAR]);
    831   return cast<VarDecl>(DS->getSingleDecl());
    832 }
    833 
    834 void SwitchStmt::setConditionVariable(const ASTContext &C, VarDecl *V) {
    835   if (!V) {
    836     SubExprs[VAR] = nullptr;
    837     return;
    838   }
    839 
    840   SourceRange VarRange = V->getSourceRange();
    841   SubExprs[VAR] = new (C) DeclStmt(DeclGroupRef(V), VarRange.getBegin(),
    842                                    VarRange.getEnd());
    843 }
    844 
    845 Stmt *SwitchCase::getSubStmt() {
    846   if (isa<CaseStmt>(this))
    847     return cast<CaseStmt>(this)->getSubStmt();
    848   return cast<DefaultStmt>(this)->getSubStmt();
    849 }
    850 
    851 WhileStmt::WhileStmt(const ASTContext &C, VarDecl *Var, Expr *cond, Stmt *body,
    852                      SourceLocation WL)
    853   : Stmt(WhileStmtClass) {
    854   setConditionVariable(C, Var);
    855   SubExprs[COND] = cond;
    856   SubExprs[BODY] = body;
    857   WhileLoc = WL;
    858 }
    859 
    860 VarDecl *WhileStmt::getConditionVariable() const {
    861   if (!SubExprs[VAR])
    862     return nullptr;
    863 
    864   DeclStmt *DS = cast<DeclStmt>(SubExprs[VAR]);
    865   return cast<VarDecl>(DS->getSingleDecl());
    866 }
    867 
    868 void WhileStmt::setConditionVariable(const ASTContext &C, VarDecl *V) {
    869   if (!V) {
    870     SubExprs[VAR] = nullptr;
    871     return;
    872   }
    873 
    874   SourceRange VarRange = V->getSourceRange();
    875   SubExprs[VAR] = new (C) DeclStmt(DeclGroupRef(V), VarRange.getBegin(),
    876                                    VarRange.getEnd());
    877 }
    878 
    879 // IndirectGotoStmt
    880 LabelDecl *IndirectGotoStmt::getConstantTarget() {
    881   if (AddrLabelExpr *E =
    882         dyn_cast<AddrLabelExpr>(getTarget()->IgnoreParenImpCasts()))
    883     return E->getLabel();
    884   return nullptr;
    885 }
    886 
    887 // ReturnStmt
    888 const Expr* ReturnStmt::getRetValue() const {
    889   return cast_or_null<Expr>(RetExpr);
    890 }
    891 Expr* ReturnStmt::getRetValue() {
    892   return cast_or_null<Expr>(RetExpr);
    893 }
    894 
    895 SEHTryStmt::SEHTryStmt(bool IsCXXTry,
    896                        SourceLocation TryLoc,
    897                        Stmt *TryBlock,
    898                        Stmt *Handler)
    899   : Stmt(SEHTryStmtClass),
    900     IsCXXTry(IsCXXTry),
    901     TryLoc(TryLoc)
    902 {
    903   Children[TRY]     = TryBlock;
    904   Children[HANDLER] = Handler;
    905 }
    906 
    907 SEHTryStmt* SEHTryStmt::Create(const ASTContext &C, bool IsCXXTry,
    908                                SourceLocation TryLoc, Stmt *TryBlock,
    909                                Stmt *Handler) {
    910   return new(C) SEHTryStmt(IsCXXTry,TryLoc,TryBlock,Handler);
    911 }
    912 
    913 SEHExceptStmt* SEHTryStmt::getExceptHandler() const {
    914   return dyn_cast<SEHExceptStmt>(getHandler());
    915 }
    916 
    917 SEHFinallyStmt* SEHTryStmt::getFinallyHandler() const {
    918   return dyn_cast<SEHFinallyStmt>(getHandler());
    919 }
    920 
    921 SEHExceptStmt::SEHExceptStmt(SourceLocation Loc,
    922                              Expr *FilterExpr,
    923                              Stmt *Block)
    924   : Stmt(SEHExceptStmtClass),
    925     Loc(Loc)
    926 {
    927   Children[FILTER_EXPR] = FilterExpr;
    928   Children[BLOCK]       = Block;
    929 }
    930 
    931 SEHExceptStmt* SEHExceptStmt::Create(const ASTContext &C, SourceLocation Loc,
    932                                      Expr *FilterExpr, Stmt *Block) {
    933   return new(C) SEHExceptStmt(Loc,FilterExpr,Block);
    934 }
    935 
    936 SEHFinallyStmt::SEHFinallyStmt(SourceLocation Loc,
    937                                Stmt *Block)
    938   : Stmt(SEHFinallyStmtClass),
    939     Loc(Loc),
    940     Block(Block)
    941 {}
    942 
    943 SEHFinallyStmt* SEHFinallyStmt::Create(const ASTContext &C, SourceLocation Loc,
    944                                        Stmt *Block) {
    945   return new(C)SEHFinallyStmt(Loc,Block);
    946 }
    947 
    948 CapturedStmt::Capture::Capture(SourceLocation Loc, VariableCaptureKind Kind,
    949                                VarDecl *Var)
    950     : VarAndKind(Var, Kind), Loc(Loc) {
    951   switch (Kind) {
    952   case VCK_This:
    953     assert(!Var && "'this' capture cannot have a variable!");
    954     break;
    955   case VCK_ByRef:
    956     assert(Var && "capturing by reference must have a variable!");
    957     break;
    958   case VCK_ByCopy:
    959     assert(Var && "capturing by copy must have a variable!");
    960     assert(
    961         (Var->getType()->isScalarType() || (Var->getType()->isReferenceType() &&
    962                                             Var->getType()
    963                                                 ->castAs<ReferenceType>()
    964                                                 ->getPointeeType()
    965                                                 ->isScalarType())) &&
    966         "captures by copy are expected to have a scalar type!");
    967     break;
    968   case VCK_VLAType:
    969     assert(!Var &&
    970            "Variable-length array type capture cannot have a variable!");
    971     break;
    972   }
    973 }
    974 
    975 CapturedStmt::Capture *CapturedStmt::getStoredCaptures() const {
    976   unsigned Size = sizeof(CapturedStmt) + sizeof(Stmt *) * (NumCaptures + 1);
    977 
    978   // Offset of the first Capture object.
    979   unsigned FirstCaptureOffset =
    980     llvm::RoundUpToAlignment(Size, llvm::alignOf<Capture>());
    981 
    982   return reinterpret_cast<Capture *>(
    983       reinterpret_cast<char *>(const_cast<CapturedStmt *>(this))
    984       + FirstCaptureOffset);
    985 }
    986 
    987 CapturedStmt::CapturedStmt(Stmt *S, CapturedRegionKind Kind,
    988                            ArrayRef<Capture> Captures,
    989                            ArrayRef<Expr *> CaptureInits,
    990                            CapturedDecl *CD,
    991                            RecordDecl *RD)
    992   : Stmt(CapturedStmtClass), NumCaptures(Captures.size()),
    993     CapDeclAndKind(CD, Kind), TheRecordDecl(RD) {
    994   assert( S && "null captured statement");
    995   assert(CD && "null captured declaration for captured statement");
    996   assert(RD && "null record declaration for captured statement");
    997 
    998   // Copy initialization expressions.
    999   Stmt **Stored = getStoredStmts();
   1000   for (unsigned I = 0, N = NumCaptures; I != N; ++I)
   1001     *Stored++ = CaptureInits[I];
   1002 
   1003   // Copy the statement being captured.
   1004   *Stored = S;
   1005 
   1006   // Copy all Capture objects.
   1007   Capture *Buffer = getStoredCaptures();
   1008   std::copy(Captures.begin(), Captures.end(), Buffer);
   1009 }
   1010 
   1011 CapturedStmt::CapturedStmt(EmptyShell Empty, unsigned NumCaptures)
   1012   : Stmt(CapturedStmtClass, Empty), NumCaptures(NumCaptures),
   1013     CapDeclAndKind(nullptr, CR_Default), TheRecordDecl(nullptr) {
   1014   getStoredStmts()[NumCaptures] = nullptr;
   1015 }
   1016 
   1017 CapturedStmt *CapturedStmt::Create(const ASTContext &Context, Stmt *S,
   1018                                    CapturedRegionKind Kind,
   1019                                    ArrayRef<Capture> Captures,
   1020                                    ArrayRef<Expr *> CaptureInits,
   1021                                    CapturedDecl *CD,
   1022                                    RecordDecl *RD) {
   1023   // The layout is
   1024   //
   1025   // -----------------------------------------------------------
   1026   // | CapturedStmt, Init, ..., Init, S, Capture, ..., Capture |
   1027   // ----------------^-------------------^----------------------
   1028   //                 getStoredStmts()    getStoredCaptures()
   1029   //
   1030   // where S is the statement being captured.
   1031   //
   1032   assert(CaptureInits.size() == Captures.size() && "wrong number of arguments");
   1033 
   1034   unsigned Size = sizeof(CapturedStmt) + sizeof(Stmt *) * (Captures.size() + 1);
   1035   if (!Captures.empty()) {
   1036     // Realign for the following Capture array.
   1037     Size = llvm::RoundUpToAlignment(Size, llvm::alignOf<Capture>());
   1038     Size += sizeof(Capture) * Captures.size();
   1039   }
   1040 
   1041   void *Mem = Context.Allocate(Size);
   1042   return new (Mem) CapturedStmt(S, Kind, Captures, CaptureInits, CD, RD);
   1043 }
   1044 
   1045 CapturedStmt *CapturedStmt::CreateDeserialized(const ASTContext &Context,
   1046                                                unsigned NumCaptures) {
   1047   unsigned Size = sizeof(CapturedStmt) + sizeof(Stmt *) * (NumCaptures + 1);
   1048   if (NumCaptures > 0) {
   1049     // Realign for the following Capture array.
   1050     Size = llvm::RoundUpToAlignment(Size, llvm::alignOf<Capture>());
   1051     Size += sizeof(Capture) * NumCaptures;
   1052   }
   1053 
   1054   void *Mem = Context.Allocate(Size);
   1055   return new (Mem) CapturedStmt(EmptyShell(), NumCaptures);
   1056 }
   1057 
   1058 Stmt::child_range CapturedStmt::children() {
   1059   // Children are captured field initilizers.
   1060   return child_range(getStoredStmts(), getStoredStmts() + NumCaptures);
   1061 }
   1062 
   1063 bool CapturedStmt::capturesVariable(const VarDecl *Var) const {
   1064   for (const auto &I : captures()) {
   1065     if (!I.capturesVariable())
   1066       continue;
   1067 
   1068     // This does not handle variable redeclarations. This should be
   1069     // extended to capture variables with redeclarations, for example
   1070     // a thread-private variable in OpenMP.
   1071     if (I.getCapturedVar() == Var)
   1072       return true;
   1073   }
   1074 
   1075   return false;
   1076 }
   1077