1//===--- Builtins.h - Builtin function header -------------------*- C++ -*-===//
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/// \file
10/// Defines enum values for all the target-independent builtin
11/// functions.
12///
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_BASIC_BUILTINS_H
16#define LLVM_CLANG_BASIC_BUILTINS_H
17
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/ADT/StringMap.h"
20#include "llvm/ADT/StringRef.h"
21#include <cstring>
22
23// VC++ defines 'alloca' as an object-like macro, which interferes with our
24// builtins.
25#undef alloca
26
27namespace clang {
28class TargetInfo;
29class IdentifierTable;
30class LangOptions;
31
32enum LanguageID : uint16_t {
33  GNU_LANG = 0x1,            // builtin requires GNU mode.
34  C_LANG = 0x2,              // builtin for c only.
35  CXX_LANG = 0x4,            // builtin for cplusplus only.
36  OBJC_LANG = 0x8,           // builtin for objective-c and objective-c++
37  MS_LANG = 0x10,            // builtin requires MS mode.
38  OMP_LANG = 0x20,           // builtin requires OpenMP.
39  CUDA_LANG = 0x40,          // builtin requires CUDA.
40  COR_LANG = 0x80,           // builtin requires use of 'fcoroutine-ts' option.
41  OCL_GAS = 0x100,           // builtin requires OpenCL generic address space.
42  OCL_PIPE = 0x200,          // builtin requires OpenCL pipe.
43  OCL_DSE = 0x400,           // builtin requires OpenCL device side enqueue.
44  ALL_OCL_LANGUAGES = 0x800, // builtin for OCL languages.
45  HLSL_LANG = 0x1000,        // builtin requires HLSL.
46  ALL_LANGUAGES = C_LANG | CXX_LANG | OBJC_LANG, // builtin for all languages.
47  ALL_GNU_LANGUAGES = ALL_LANGUAGES | GNU_LANG,  // builtin requires GNU mode.
48  ALL_MS_LANGUAGES = ALL_LANGUAGES | MS_LANG     // builtin requires MS mode.
49};
50
51struct HeaderDesc {
52  enum HeaderID : uint16_t {
53#define HEADER(ID, NAME) ID,
54#include "clang/Basic/BuiltinHeaders.def"
55#undef HEADER
56  } ID;
57
58  constexpr HeaderDesc(HeaderID ID) : ID(ID) {}
59
60  const char *getName() const;
61};
62
63namespace Builtin {
64enum ID {
65  NotBuiltin  = 0,      // This is not a builtin function.
66#define BUILTIN(ID, TYPE, ATTRS) BI##ID,
67#include "clang/Basic/Builtins.def"
68  FirstTSBuiltin
69};
70
71struct Info {
72  llvm::StringLiteral Name;
73  const char *Type, *Attributes;
74  const char *Features;
75  HeaderDesc Header;
76  LanguageID Langs;
77};
78
79/// Holds information about both target-independent and
80/// target-specific builtins, allowing easy queries by clients.
81///
82/// Builtins from an optional auxiliary target are stored in
83/// AuxTSRecords. Their IDs are shifted up by TSRecords.size() and need to
84/// be translated back with getAuxBuiltinID() before use.
85class Context {
86  llvm::ArrayRef<Info> TSRecords;
87  llvm::ArrayRef<Info> AuxTSRecords;
88
89public:
90  Context() = default;
91
92  /// Perform target-specific initialization
93  /// \param AuxTarget Target info to incorporate builtins from. May be nullptr.
94  void InitializeTarget(const TargetInfo &Target, const TargetInfo *AuxTarget);
95
96  /// Mark the identifiers for all the builtins with their
97  /// appropriate builtin ID # and mark any non-portable builtin identifiers as
98  /// such.
99  void initializeBuiltins(IdentifierTable &Table, const LangOptions& LangOpts);
100
101  /// Return the identifier name for the specified builtin,
102  /// e.g. "__builtin_abs".
103  llvm::StringRef getName(unsigned ID) const { return getRecord(ID).Name; }
104
105  /// Get the type descriptor string for the specified builtin.
106  const char *getTypeString(unsigned ID) const {
107    return getRecord(ID).Type;
108  }
109
110  /// Return true if this function is a target-specific builtin.
111  bool isTSBuiltin(unsigned ID) const {
112    return ID >= Builtin::FirstTSBuiltin;
113  }
114
115  /// Return true if this function has no side effects.
116  bool isPure(unsigned ID) const {
117    return strchr(getRecord(ID).Attributes, 'U') != nullptr;
118  }
119
120  /// Return true if this function has no side effects and doesn't
121  /// read memory.
122  bool isConst(unsigned ID) const {
123    return strchr(getRecord(ID).Attributes, 'c') != nullptr;
124  }
125
126  /// Return true if we know this builtin never throws an exception.
127  bool isNoThrow(unsigned ID) const {
128    return strchr(getRecord(ID).Attributes, 'n') != nullptr;
129  }
130
131  /// Return true if we know this builtin never returns.
132  bool isNoReturn(unsigned ID) const {
133    return strchr(getRecord(ID).Attributes, 'r') != nullptr;
134  }
135
136  /// Return true if we know this builtin can return twice.
137  bool isReturnsTwice(unsigned ID) const {
138    return strchr(getRecord(ID).Attributes, 'j') != nullptr;
139  }
140
141  /// Returns true if this builtin does not perform the side-effects
142  /// of its arguments.
143  bool isUnevaluated(unsigned ID) const {
144    return strchr(getRecord(ID).Attributes, 'u') != nullptr;
145  }
146
147  /// Return true if this is a builtin for a libc/libm function,
148  /// with a "__builtin_" prefix (e.g. __builtin_abs).
149  bool isLibFunction(unsigned ID) const {
150    return strchr(getRecord(ID).Attributes, 'F') != nullptr;
151  }
152
153  /// Determines whether this builtin is a predefined libc/libm
154  /// function, such as "malloc", where we know the signature a
155  /// priori.
156  /// In C, such functions behave as if they are predeclared,
157  /// possibly with a warning on first use. In Objective-C and C++,
158  /// they do not, but they are recognized as builtins once we see
159  /// a declaration.
160  bool isPredefinedLibFunction(unsigned ID) const {
161    return strchr(getRecord(ID).Attributes, 'f') != nullptr;
162  }
163
164  /// Returns true if this builtin requires appropriate header in other
165  /// compilers. In Clang it will work even without including it, but we can emit
166  /// a warning about missing header.
167  bool isHeaderDependentFunction(unsigned ID) const {
168    return strchr(getRecord(ID).Attributes, 'h') != nullptr;
169  }
170
171  /// Determines whether this builtin is a predefined compiler-rt/libgcc
172  /// function, such as "__clear_cache", where we know the signature a
173  /// priori.
174  bool isPredefinedRuntimeFunction(unsigned ID) const {
175    return strchr(getRecord(ID).Attributes, 'i') != nullptr;
176  }
177
178  /// Determines whether this builtin is a C++ standard library function
179  /// that lives in (possibly-versioned) namespace std, possibly a template
180  /// specialization, where the signature is determined by the standard library
181  /// declaration.
182  bool isInStdNamespace(unsigned ID) const {
183    return strchr(getRecord(ID).Attributes, 'z') != nullptr;
184  }
185
186  /// Determines whether this builtin can have its address taken with no
187  /// special action required.
188  bool isDirectlyAddressable(unsigned ID) const {
189    // Most standard library functions can have their addresses taken. C++
190    // standard library functions formally cannot in C++20 onwards, and when
191    // we allow it, we need to ensure we instantiate a definition.
192    return isPredefinedLibFunction(ID) && !isInStdNamespace(ID);
193  }
194
195  /// Determines whether this builtin has custom typechecking.
196  bool hasCustomTypechecking(unsigned ID) const {
197    return strchr(getRecord(ID).Attributes, 't') != nullptr;
198  }
199
200  /// Determines whether a declaration of this builtin should be recognized
201  /// even if the type doesn't match the specified signature.
202  bool allowTypeMismatch(unsigned ID) const {
203    return strchr(getRecord(ID).Attributes, 'T') != nullptr ||
204           hasCustomTypechecking(ID);
205  }
206
207  /// Determines whether this builtin has a result or any arguments which
208  /// are pointer types.
209  bool hasPtrArgsOrResult(unsigned ID) const {
210    return strchr(getRecord(ID).Type, '*') != nullptr;
211  }
212
213  /// Return true if this builtin has a result or any arguments which are
214  /// reference types.
215  bool hasReferenceArgsOrResult(unsigned ID) const {
216    return strchr(getRecord(ID).Type, '&') != nullptr ||
217           strchr(getRecord(ID).Type, 'A') != nullptr;
218  }
219
220  /// If this is a library function that comes from a specific
221  /// header, retrieve that header name.
222  const char *getHeaderName(unsigned ID) const {
223    return getRecord(ID).Header.getName();
224  }
225
226  /// Determine whether this builtin is like printf in its
227  /// formatting rules and, if so, set the index to the format string
228  /// argument and whether this function as a va_list argument.
229  bool isPrintfLike(unsigned ID, unsigned &FormatIdx, bool &HasVAListArg);
230
231  /// Determine whether this builtin is like scanf in its
232  /// formatting rules and, if so, set the index to the format string
233  /// argument and whether this function as a va_list argument.
234  bool isScanfLike(unsigned ID, unsigned &FormatIdx, bool &HasVAListArg);
235
236  /// Determine whether this builtin has callback behavior (see
237  /// llvm::AbstractCallSites for details). If so, add the index to the
238  /// callback callee argument and the callback payload arguments.
239  bool performsCallback(unsigned ID,
240                        llvm::SmallVectorImpl<int> &Encoding) const;
241
242  /// Return true if this function has no side effects and doesn't
243  /// read memory, except for possibly errno or raising FP exceptions.
244  ///
245  /// Such functions can be const when the MathErrno lang option and FP
246  /// exceptions are disabled.
247  bool isConstWithoutErrnoAndExceptions(unsigned ID) const {
248    return strchr(getRecord(ID).Attributes, 'e') != nullptr;
249  }
250
251  bool isConstWithoutExceptions(unsigned ID) const {
252    return strchr(getRecord(ID).Attributes, 'g') != nullptr;
253  }
254
255  const char *getRequiredFeatures(unsigned ID) const {
256    return getRecord(ID).Features;
257  }
258
259  unsigned getRequiredVectorWidth(unsigned ID) const;
260
261  /// Return true if builtin ID belongs to AuxTarget.
262  bool isAuxBuiltinID(unsigned ID) const {
263    return ID >= (Builtin::FirstTSBuiltin + TSRecords.size());
264  }
265
266  /// Return real builtin ID (i.e. ID it would have during compilation
267  /// for AuxTarget).
268  unsigned getAuxBuiltinID(unsigned ID) const { return ID - TSRecords.size(); }
269
270  /// Returns true if this is a libc/libm function without the '__builtin_'
271  /// prefix.
272  static bool isBuiltinFunc(llvm::StringRef Name);
273
274  /// Returns true if this is a builtin that can be redeclared.  Returns true
275  /// for non-builtins.
276  bool canBeRedeclared(unsigned ID) const;
277
278  /// Return true if this function can be constant evaluated by Clang frontend.
279  bool isConstantEvaluated(unsigned ID) const {
280    return strchr(getRecord(ID).Attributes, 'E') != nullptr;
281  }
282
283private:
284  const Info &getRecord(unsigned ID) const;
285
286  /// Helper function for isPrintfLike and isScanfLike.
287  bool isLike(unsigned ID, unsigned &FormatIdx, bool &HasVAListArg,
288              const char *Fmt) const;
289};
290
291/// Returns true if the required target features of a builtin function are
292/// enabled.
293/// \p TargetFeatureMap maps a target feature to true if it is enabled and
294///    false if it is disabled.
295bool evaluateRequiredTargetFeatures(
296    llvm::StringRef RequiredFatures,
297    const llvm::StringMap<bool> &TargetFetureMap);
298
299} // namespace Builtin
300
301/// Kinds of BuiltinTemplateDecl.
302enum BuiltinTemplateKind : int {
303  /// This names the __make_integer_seq BuiltinTemplateDecl.
304  BTK__make_integer_seq,
305
306  /// This names the __type_pack_element BuiltinTemplateDecl.
307  BTK__type_pack_element
308};
309
310} // end namespace clang
311#endif
312