clang/lib/Basic/Builtins.cpp

   1 //===--- Builtins.cpp - Builtin function implementation -------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //  This file implements various things for builtin functions.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "clang/Basic/Builtins.h"
  14 #include "BuiltinTargetFeatures.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 const char *HeaderDesc::getName() const {
  22   switch (ID) {
  23 #define HEADER(ID, NAME)                                                       \
  24   case ID:                                                                     \
  25     return NAME;
  26 #include "clang/Basic/BuiltinHeaders.def"
  27 #undef HEADER
  28   };
  29   llvm_unreachable("Unknown HeaderDesc::HeaderID enum");
  30 }
  31
  32 static constexpr Builtin::Info BuiltinInfo[] = {
  33     {"not a builtin function", nullptr, nullptr, nullptr, HeaderDesc::NO_HEADER,
  34      ALL_LANGUAGES},
  35 #define BUILTIN(ID, TYPE, ATTRS)                                               \
  36   {#ID, TYPE, ATTRS, nullptr, HeaderDesc::NO_HEADER, ALL_LANGUAGES},
  37 #define LANGBUILTIN(ID, TYPE, ATTRS, LANGS)                                    \
  38   {#ID, TYPE, ATTRS, nullptr, HeaderDesc::NO_HEADER, LANGS},
  39 #define LIBBUILTIN(ID, TYPE, ATTRS, HEADER, LANGS)                             \
  40   {#ID, TYPE, ATTRS, nullptr, HeaderDesc::HEADER, LANGS},
  41 #include "clang/Basic/Builtins.inc"
  42 };
  43
  44 const Builtin::Info &Builtin::Context::getRecord(unsigned ID) const {
  45   if (ID < Builtin::FirstTSBuiltin)
  46     return BuiltinInfo[ID];
  47   assert(((ID - Builtin::FirstTSBuiltin) <
  48           (TSRecords.size() + AuxTSRecords.size())) &&
  49          "Invalid builtin ID!");
  50   if (isAuxBuiltinID(ID))
  51     return AuxTSRecords[getAuxBuiltinID(ID) - Builtin::FirstTSBuiltin];
  52   return TSRecords[ID - Builtin::FirstTSBuiltin];
  53 }
  54
  55 void Builtin::Context::InitializeTarget(const TargetInfo &Target,
  56                                         const TargetInfo *AuxTarget) {
  57   assert(TSRecords.empty() && "Already initialized target?");
  58   TSRecords = Target.getTargetBuiltins();
  59   if (AuxTarget)
  60     AuxTSRecords = AuxTarget->getTargetBuiltins();
  61 }
  62
  63 bool Builtin::Context::isBuiltinFunc(llvm::StringRef FuncName) {
  64   bool InStdNamespace = FuncName.consume_front("std-");
  65   for (unsigned i = Builtin::NotBuiltin + 1; i != Builtin::FirstTSBuiltin;
  66        ++i) {
  67     if (FuncName == BuiltinInfo[i].Name &&
  68         (bool)strchr(BuiltinInfo[i].Attributes, 'z') == InStdNamespace)
  69       return strchr(BuiltinInfo[i].Attributes, 'f') != nullptr;
  70   }
  71
  72   return false;
  73 }
  74
  75 /// Is this builtin supported according to the given language options?
  76 static bool builtinIsSupported(const Builtin::Info &BuiltinInfo,
  77                                const LangOptions &LangOpts) {
  78   /* Builtins Unsupported */
  79   if (LangOpts.NoBuiltin && strchr(BuiltinInfo.Attributes, 'f') != nullptr)
  80     return false;
  81   /* CorBuiltins Unsupported */
  82   if (!LangOpts.Coroutines && (BuiltinInfo.Langs & COR_LANG))
  83     return false;
  84   /* MathBuiltins Unsupported */
  85   if (LangOpts.NoMathBuiltin && BuiltinInfo.Header.ID == HeaderDesc::MATH_H)
  86     return false;
  87   /* GnuMode Unsupported */
  88   if (!LangOpts.GNUMode && (BuiltinInfo.Langs & GNU_LANG))
  89     return false;
  90   /* MSMode Unsupported */
  91   if (!LangOpts.MicrosoftExt && (BuiltinInfo.Langs & MS_LANG))
  92     return false;
  93   /* HLSLMode Unsupported */
  94   if (!LangOpts.HLSL && (BuiltinInfo.Langs & HLSL_LANG))
  95     return false;
  96   /* ObjC Unsupported */
  97   if (!LangOpts.ObjC && BuiltinInfo.Langs == OBJC_LANG)
  98     return false;
  99   /* OpenCLC Unsupported */
 100   if (!LangOpts.OpenCL && (BuiltinInfo.Langs & ALL_OCL_LANGUAGES))
 101     return false;
 102   /* OopenCL GAS Unsupported */
 103   if (!LangOpts.OpenCLGenericAddressSpace && (BuiltinInfo.Langs & OCL_GAS))
 104     return false;
 105   /* OpenCL Pipe Unsupported */
 106   if (!LangOpts.OpenCLPipes && (BuiltinInfo.Langs & OCL_PIPE))
 107     return false;
 108
 109   // Device side enqueue is not supported until OpenCL 2.0. In 2.0 and higher
 110   // support is indicated with language option for blocks.
 111
 112   /* OpenCL DSE Unsupported */
 113   if ((LangOpts.getOpenCLCompatibleVersion() < 200 || !LangOpts.Blocks) &&
 114       (BuiltinInfo.Langs & OCL_DSE))
 115     return false;
 116   /* OpenMP Unsupported */
 117   if (!LangOpts.OpenMP && BuiltinInfo.Langs == OMP_LANG)
 118     return false;
 119   /* CUDA Unsupported */
 120   if (!LangOpts.CUDA && BuiltinInfo.Langs == CUDA_LANG)
 121     return false;
 122   /* CPlusPlus Unsupported */
 123   if (!LangOpts.CPlusPlus && BuiltinInfo.Langs == CXX_LANG)
 124     return false;
 125   /* consteval Unsupported */
 126   if (!LangOpts.CPlusPlus20 && strchr(BuiltinInfo.Attributes, 'G') != nullptr)
 127     return false;
 128   return true;
 129 }
 130
 131 /// initializeBuiltins - Mark the identifiers for all the builtins with their
 132 /// appropriate builtin ID # and mark any non-portable builtin identifiers as
 133 /// such.
 134 void Builtin::Context::initializeBuiltins(IdentifierTable &Table,
 135                                           const LangOptions& LangOpts) {
 136   // Step #1: mark all target-independent builtins with their ID's.
 137   for (unsigned i = Builtin::NotBuiltin+1; i != Builtin::FirstTSBuiltin; ++i)
 138     if (builtinIsSupported(BuiltinInfo[i], LangOpts)) {
 139       Table.get(BuiltinInfo[i].Name).setBuiltinID(i);
 140     }
 141
 142   // Step #2: Register target-specific builtins.
 143   for (unsigned i = 0, e = TSRecords.size(); i != e; ++i)
 144     if (builtinIsSupported(TSRecords[i], LangOpts))
 145       Table.get(TSRecords[i].Name).setBuiltinID(i + Builtin::FirstTSBuiltin);
 146
 147   // Step #3: Register target-specific builtins for AuxTarget.
 148   for (unsigned i = 0, e = AuxTSRecords.size(); i != e; ++i)
 149     Table.get(AuxTSRecords[i].Name)
 150         .setBuiltinID(i + Builtin::FirstTSBuiltin + TSRecords.size());
 151
 152   // Step #4: Unregister any builtins specified by -fno-builtin-foo.
 153   for (llvm::StringRef Name : LangOpts.NoBuiltinFuncs) {
 154     bool InStdNamespace = Name.consume_front("std-");
 155     auto NameIt = Table.find(Name);
 156     if (NameIt != Table.end()) {
 157       unsigned ID = NameIt->second->getBuiltinID();
 158       if (ID != Builtin::NotBuiltin && isPredefinedLibFunction(ID) &&
 159           isInStdNamespace(ID) == InStdNamespace) {
 160         NameIt->second->clearBuiltinID();
 161       }
 162     }
 163   }
 164 }
 165
 166 unsigned Builtin::Context::getRequiredVectorWidth(unsigned ID) const {
 167   const char *WidthPos = ::strchr(getRecord(ID).Attributes, 'V');
 168   if (!WidthPos)
 169     return 0;
 170
 171   ++WidthPos;
 172   assert(*WidthPos == ':' &&
 173          "Vector width specifier must be followed by a ':'");
 174   ++WidthPos;
 175
 176   char *EndPos;
 177   unsigned Width = ::strtol(WidthPos, &EndPos, 10);
 178   assert(*EndPos == ':' && "Vector width specific must end with a ':'");
 179   return Width;
 180 }
 181
 182 bool Builtin::Context::isLike(unsigned ID, unsigned &FormatIdx,
 183                               bool &HasVAListArg, const char *Fmt) const {
 184   assert(Fmt && "Not passed a format string");
 185   assert(::strlen(Fmt) == 2 &&
 186          "Format string needs to be two characters long");
 187   assert(::toupper(Fmt[0]) == Fmt[1] &&
 188          "Format string is not in the form \"xX\"");
 189
 190   const char *Like = ::strpbrk(getRecord(ID).Attributes, Fmt);
 191   if (!Like)
 192     return false;
 193
 194   HasVAListArg = (*Like == Fmt[1]);
 195
 196   ++Like;
 197   assert(*Like == ':' && "Format specifier must be followed by a ':'");
 198   ++Like;
 199
 200   assert(::strchr(Like, ':') && "Format specifier must end with a ':'");
 201   FormatIdx = ::strtol(Like, nullptr, 10);
 202   return true;
 203 }
 204
 205 bool Builtin::Context::isPrintfLike(unsigned ID, unsigned &FormatIdx,
 206                                     bool &HasVAListArg) {
 207   return isLike(ID, FormatIdx, HasVAListArg, "pP");
 208 }
 209
 210 bool Builtin::Context::isScanfLike(unsigned ID, unsigned &FormatIdx,
 211                                    bool &HasVAListArg) {
 212   return isLike(ID, FormatIdx, HasVAListArg, "sS");
 213 }
 214
 215 bool Builtin::Context::performsCallback(unsigned ID,
 216                                         SmallVectorImpl<int> &Encoding) const {
 217   const char *CalleePos = ::strchr(getRecord(ID).Attributes, 'C');
 218   if (!CalleePos)
 219     return false;
 220
 221   ++CalleePos;
 222   assert(*CalleePos == '<' &&
 223          "Callback callee specifier must be followed by a '<'");
 224   ++CalleePos;
 225
 226   char *EndPos;
 227   int CalleeIdx = ::strtol(CalleePos, &EndPos, 10);
 228   assert(CalleeIdx >= 0 && "Callee index is supposed to be positive!");
 229   Encoding.push_back(CalleeIdx);
 230
 231   while (*EndPos == ',') {
 232     const char *PayloadPos = EndPos + 1;
 233
 234     int PayloadIdx = ::strtol(PayloadPos, &EndPos, 10);
 235     Encoding.push_back(PayloadIdx);
 236   }
 237
 238   assert(*EndPos == '>' && "Callback callee specifier must end with a '>'");
 239   return true;
 240 }
 241
 242 bool Builtin::Context::canBeRedeclared(unsigned ID) const {
 243   return ID == Builtin::NotBuiltin || ID == Builtin::BI__va_start ||
 244          ID == Builtin::BI__builtin_assume_aligned ||
 245          (!hasReferenceArgsOrResult(ID) && !hasCustomTypechecking(ID)) ||
 246          isInStdNamespace(ID);
 247 }
 248
 249 bool Builtin::evaluateRequiredTargetFeatures(
 250     StringRef RequiredFeatures, const llvm::StringMap<bool> &TargetFetureMap) {
 251   // Return true if the builtin doesn't have any required features.
 252   if (RequiredFeatures.empty())
 253     return true;
 254   assert(!RequiredFeatures.contains(' ') && "Space in feature list");
 255
 256   TargetFeatures TF(TargetFetureMap);
 257   return TF.hasRequiredFeatures(RequiredFeatures);
 258 }