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 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::isBuiltinFunc(llvm::StringRef FuncName) {
52   bool InStdNamespace = FuncName.consume_front("std-");
53   for (unsigned i = Builtin::NotBuiltin + 1; i != Builtin::FirstTSBuiltin;
54        ++i) {
55     if (FuncName.equals(BuiltinInfo[i].Name) &&
56         (bool)strchr(BuiltinInfo[i].Attributes, 'z') == InStdNamespace)
57       return strchr(BuiltinInfo[i].Attributes, 'f') != nullptr;
58   }
59 
60   return false;
61 }
62 
63 /// Is this builtin supported according to the given language options?
64 static bool builtinIsSupported(const Builtin::Info &BuiltinInfo,
65                                const LangOptions &LangOpts) {
66   bool BuiltinsUnsupported =
67       LangOpts.NoBuiltin && strchr(BuiltinInfo.Attributes, 'f') != nullptr;
68   bool CorBuiltinsUnsupported =
69       !LangOpts.Coroutines && (BuiltinInfo.Langs & COR_LANG);
70   bool MathBuiltinsUnsupported =
71     LangOpts.NoMathBuiltin && BuiltinInfo.HeaderName &&
72     llvm::StringRef(BuiltinInfo.HeaderName).equals("math.h");
73   bool GnuModeUnsupported = !LangOpts.GNUMode && (BuiltinInfo.Langs & GNU_LANG);
74   bool MSModeUnsupported =
75       !LangOpts.MicrosoftExt && (BuiltinInfo.Langs & MS_LANG);
76   bool ObjCUnsupported = !LangOpts.ObjC && BuiltinInfo.Langs == OBJC_LANG;
77   bool OclCUnsupported =
78       !LangOpts.OpenCL && (BuiltinInfo.Langs & ALL_OCL_LANGUAGES);
79   bool OclGASUnsupported =
80       !LangOpts.OpenCLGenericAddressSpace && (BuiltinInfo.Langs & OCL_GAS);
81   bool OclPipeUnsupported =
82       !LangOpts.OpenCLPipes && (BuiltinInfo.Langs & OCL_PIPE);
83   // Device side enqueue is not supported until OpenCL 2.0. In 2.0 and higher
84   // support is indicated with language option for blocks.
85   bool OclDSEUnsupported =
86       (LangOpts.getOpenCLCompatibleVersion() < 200 || !LangOpts.Blocks) &&
87       (BuiltinInfo.Langs & OCL_DSE);
88   bool OpenMPUnsupported = !LangOpts.OpenMP && BuiltinInfo.Langs == OMP_LANG;
89   bool CUDAUnsupported = !LangOpts.CUDA && BuiltinInfo.Langs == CUDA_LANG;
90   bool CPlusPlusUnsupported =
91       !LangOpts.CPlusPlus && BuiltinInfo.Langs == CXX_LANG;
92   return !BuiltinsUnsupported && !CorBuiltinsUnsupported &&
93          !MathBuiltinsUnsupported && !OclCUnsupported && !OclGASUnsupported &&
94          !OclPipeUnsupported && !OclDSEUnsupported && !OpenMPUnsupported &&
95          !GnuModeUnsupported && !MSModeUnsupported && !ObjCUnsupported &&
96          !CPlusPlusUnsupported && !CUDAUnsupported;
97 }
98 
99 /// initializeBuiltins - Mark the identifiers for all the builtins with their
100 /// appropriate builtin ID # and mark any non-portable builtin identifiers as
101 /// such.
102 void Builtin::Context::initializeBuiltins(IdentifierTable &Table,
103                                           const LangOptions& LangOpts) {
104   // Step #1: mark all target-independent builtins with their ID's.
105   for (unsigned i = Builtin::NotBuiltin+1; i != Builtin::FirstTSBuiltin; ++i)
106     if (builtinIsSupported(BuiltinInfo[i], LangOpts)) {
107       Table.get(BuiltinInfo[i].Name).setBuiltinID(i);
108     }
109 
110   // Step #2: Register target-specific builtins.
111   for (unsigned i = 0, e = TSRecords.size(); i != e; ++i)
112     if (builtinIsSupported(TSRecords[i], LangOpts))
113       Table.get(TSRecords[i].Name).setBuiltinID(i + Builtin::FirstTSBuiltin);
114 
115   // Step #3: Register target-specific builtins for AuxTarget.
116   for (unsigned i = 0, e = AuxTSRecords.size(); i != e; ++i)
117     Table.get(AuxTSRecords[i].Name)
118         .setBuiltinID(i + Builtin::FirstTSBuiltin + TSRecords.size());
119 
120   // Step #4: Unregister any builtins specified by -fno-builtin-foo.
121   for (llvm::StringRef Name : LangOpts.NoBuiltinFuncs) {
122     bool InStdNamespace = Name.consume_front("std-");
123     auto NameIt = Table.find(Name);
124     if (NameIt != Table.end()) {
125       unsigned ID = NameIt->second->getBuiltinID();
126       if (ID != Builtin::NotBuiltin && isPredefinedLibFunction(ID) &&
127           isInStdNamespace(ID) == InStdNamespace) {
128         Table.get(Name).setBuiltinID(Builtin::NotBuiltin);
129       }
130     }
131   }
132 }
133 
134 unsigned Builtin::Context::getRequiredVectorWidth(unsigned ID) const {
135   const char *WidthPos = ::strchr(getRecord(ID).Attributes, 'V');
136   if (!WidthPos)
137     return 0;
138 
139   ++WidthPos;
140   assert(*WidthPos == ':' &&
141          "Vector width specifier must be followed by a ':'");
142   ++WidthPos;
143 
144   char *EndPos;
145   unsigned Width = ::strtol(WidthPos, &EndPos, 10);
146   assert(*EndPos == ':' && "Vector width specific must end with a ':'");
147   return Width;
148 }
149 
150 bool Builtin::Context::isLike(unsigned ID, unsigned &FormatIdx,
151                               bool &HasVAListArg, const char *Fmt) const {
152   assert(Fmt && "Not passed a format string");
153   assert(::strlen(Fmt) == 2 &&
154          "Format string needs to be two characters long");
155   assert(::toupper(Fmt[0]) == Fmt[1] &&
156          "Format string is not in the form \"xX\"");
157 
158   const char *Like = ::strpbrk(getRecord(ID).Attributes, Fmt);
159   if (!Like)
160     return false;
161 
162   HasVAListArg = (*Like == Fmt[1]);
163 
164   ++Like;
165   assert(*Like == ':' && "Format specifier must be followed by a ':'");
166   ++Like;
167 
168   assert(::strchr(Like, ':') && "Format specifier must end with a ':'");
169   FormatIdx = ::strtol(Like, nullptr, 10);
170   return true;
171 }
172 
173 bool Builtin::Context::isPrintfLike(unsigned ID, unsigned &FormatIdx,
174                                     bool &HasVAListArg) {
175   return isLike(ID, FormatIdx, HasVAListArg, "pP");
176 }
177 
178 bool Builtin::Context::isScanfLike(unsigned ID, unsigned &FormatIdx,
179                                    bool &HasVAListArg) {
180   return isLike(ID, FormatIdx, HasVAListArg, "sS");
181 }
182 
183 bool Builtin::Context::performsCallback(unsigned ID,
184                                         SmallVectorImpl<int> &Encoding) const {
185   const char *CalleePos = ::strchr(getRecord(ID).Attributes, 'C');
186   if (!CalleePos)
187     return false;
188 
189   ++CalleePos;
190   assert(*CalleePos == '<' &&
191          "Callback callee specifier must be followed by a '<'");
192   ++CalleePos;
193 
194   char *EndPos;
195   int CalleeIdx = ::strtol(CalleePos, &EndPos, 10);
196   assert(CalleeIdx >= 0 && "Callee index is supposed to be positive!");
197   Encoding.push_back(CalleeIdx);
198 
199   while (*EndPos == ',') {
200     const char *PayloadPos = EndPos + 1;
201 
202     int PayloadIdx = ::strtol(PayloadPos, &EndPos, 10);
203     Encoding.push_back(PayloadIdx);
204   }
205 
206   assert(*EndPos == '>' && "Callback callee specifier must end with a '>'");
207   return true;
208 }
209 
210 bool Builtin::Context::canBeRedeclared(unsigned ID) const {
211   return ID == Builtin::NotBuiltin || ID == Builtin::BI__va_start ||
212          (!hasReferenceArgsOrResult(ID) && !hasCustomTypechecking(ID)) ||
213          isInStdNamespace(ID);
214 }
215 
216 bool Builtin::evaluateRequiredTargetFeatures(
217     StringRef RequiredFeatures, const llvm::StringMap<bool> &TargetFetureMap) {
218   // Return true if the builtin doesn't have any required features.
219   if (RequiredFeatures.empty())
220     return true;
221   assert(!RequiredFeatures.contains(' ') && "Space in feature list");
222 
223   TargetFeatures TF(TargetFetureMap);
224   return TF.hasRequiredFeatures(RequiredFeatures);
225 }
226