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      1 //===--- Builtins.cpp - Builtin function 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 various things for builtin functions.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "clang/Basic/Builtins.h"
     15 #include "clang/Basic/IdentifierTable.h"
     16 #include "clang/Basic/LangOptions.h"
     17 #include "clang/Basic/TargetInfo.h"
     18 #include "llvm/ADT/StringRef.h"
     19 using namespace clang;
     20 
     21 static const Builtin::Info BuiltinInfo[] = {
     22   { "not a builtin function", nullptr, nullptr, nullptr, ALL_LANGUAGES,nullptr},
     23 #define BUILTIN(ID, TYPE, ATTRS)                                               \
     24   { #ID, TYPE, ATTRS, nullptr, ALL_LANGUAGES, nullptr },
     25 #define LANGBUILTIN(ID, TYPE, ATTRS, LANGS)                                    \
     26   { #ID, TYPE, ATTRS, nullptr, LANGS, nullptr },
     27 #define LIBBUILTIN(ID, TYPE, ATTRS, HEADER, LANGS)                             \
     28   { #ID, TYPE, ATTRS, HEADER, LANGS, nullptr },
     29 #include "clang/Basic/Builtins.def"
     30 };
     31 
     32 const Builtin::Info &Builtin::Context::getRecord(unsigned ID) const {
     33   if (ID < Builtin::FirstTSBuiltin)
     34     return BuiltinInfo[ID];
     35   assert(((ID - Builtin::FirstTSBuiltin) <
     36           (TSRecords.size() + AuxTSRecords.size())) &&
     37          "Invalid builtin ID!");
     38   if (isAuxBuiltinID(ID))
     39     return AuxTSRecords[getAuxBuiltinID(ID) - Builtin::FirstTSBuiltin];
     40   return TSRecords[ID - Builtin::FirstTSBuiltin];
     41 }
     42 
     43 void Builtin::Context::InitializeTarget(const TargetInfo &Target,
     44                                         const TargetInfo *AuxTarget) {
     45   assert(TSRecords.empty() && "Already initialized target?");
     46   TSRecords = Target.getTargetBuiltins();
     47   if (AuxTarget)
     48     AuxTSRecords = AuxTarget->getTargetBuiltins();
     49 }
     50 
     51 bool Builtin::Context::builtinIsSupported(const Builtin::Info &BuiltinInfo,
     52                                           const LangOptions &LangOpts) {
     53   bool BuiltinsUnsupported = LangOpts.NoBuiltin &&
     54                              strchr(BuiltinInfo.Attributes, 'f');
     55   bool MathBuiltinsUnsupported =
     56     LangOpts.NoMathBuiltin && BuiltinInfo.HeaderName &&
     57     llvm::StringRef(BuiltinInfo.HeaderName).equals("math.h");
     58   bool GnuModeUnsupported = !LangOpts.GNUMode && (BuiltinInfo.Langs & GNU_LANG);
     59   bool MSModeUnsupported =
     60       !LangOpts.MicrosoftExt && (BuiltinInfo.Langs & MS_LANG);
     61   bool ObjCUnsupported = !LangOpts.ObjC1 && BuiltinInfo.Langs == OBJC_LANG;
     62   return !BuiltinsUnsupported && !MathBuiltinsUnsupported &&
     63          !GnuModeUnsupported && !MSModeUnsupported && !ObjCUnsupported;
     64 }
     65 
     66 /// initializeBuiltins - Mark the identifiers for all the builtins with their
     67 /// appropriate builtin ID # and mark any non-portable builtin identifiers as
     68 /// such.
     69 void Builtin::Context::initializeBuiltins(IdentifierTable &Table,
     70                                           const LangOptions& LangOpts) {
     71   // Step #1: mark all target-independent builtins with their ID's.
     72   for (unsigned i = Builtin::NotBuiltin+1; i != Builtin::FirstTSBuiltin; ++i)
     73     if (builtinIsSupported(BuiltinInfo[i], LangOpts)) {
     74       Table.get(BuiltinInfo[i].Name).setBuiltinID(i);
     75     }
     76 
     77   // Step #2: Register target-specific builtins.
     78   for (unsigned i = 0, e = TSRecords.size(); i != e; ++i)
     79     if (builtinIsSupported(TSRecords[i], LangOpts))
     80       Table.get(TSRecords[i].Name).setBuiltinID(i + Builtin::FirstTSBuiltin);
     81 
     82   // Step #3: Register target-specific builtins for AuxTarget.
     83   for (unsigned i = 0, e = AuxTSRecords.size(); i != e; ++i)
     84     Table.get(AuxTSRecords[i].Name)
     85         .setBuiltinID(i + Builtin::FirstTSBuiltin + TSRecords.size());
     86 }
     87 
     88 void Builtin::Context::forgetBuiltin(unsigned ID, IdentifierTable &Table) {
     89   Table.get(getRecord(ID).Name).setBuiltinID(0);
     90 }
     91 
     92 bool Builtin::Context::isLike(unsigned ID, unsigned &FormatIdx,
     93                               bool &HasVAListArg, const char *Fmt) const {
     94   assert(Fmt && "Not passed a format string");
     95   assert(::strlen(Fmt) == 2 &&
     96          "Format string needs to be two characters long");
     97   assert(::toupper(Fmt[0]) == Fmt[1] &&
     98          "Format string is not in the form \"xX\"");
     99 
    100   const char *Like = ::strpbrk(getRecord(ID).Attributes, Fmt);
    101   if (!Like)
    102     return false;
    103 
    104   HasVAListArg = (*Like == Fmt[1]);
    105 
    106   ++Like;
    107   assert(*Like == ':' && "Format specifier must be followed by a ':'");
    108   ++Like;
    109 
    110   assert(::strchr(Like, ':') && "Format specifier must end with a ':'");
    111   FormatIdx = ::strtol(Like, nullptr, 10);
    112   return true;
    113 }
    114 
    115 bool Builtin::Context::isPrintfLike(unsigned ID, unsigned &FormatIdx,
    116                                     bool &HasVAListArg) {
    117   return isLike(ID, FormatIdx, HasVAListArg, "pP");
    118 }
    119 
    120 bool Builtin::Context::isScanfLike(unsigned ID, unsigned &FormatIdx,
    121                                    bool &HasVAListArg) {
    122   return isLike(ID, FormatIdx, HasVAListArg, "sS");
    123 }
    124