Builtins.cpp revision 360784 
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 "clang/Basic/IdentifierTable.h"
15#include "clang/Basic/LangOptions.h"
16#include "clang/Basic/TargetInfo.h"
17#include "llvm/ADT/StringRef.h"
18using namespace clang;
19
20static const Builtin::Info BuiltinInfo[] = {
21  { "not a builtin function", nullptr, nullptr, nullptr, ALL_LANGUAGES,nullptr},
22#define BUILTIN(ID, TYPE, ATTRS)                                               \
23  { #ID, TYPE, ATTRS, nullptr, ALL_LANGUAGES, nullptr },
24#define LANGBUILTIN(ID, TYPE, ATTRS, LANGS)                                    \
25  { #ID, TYPE, ATTRS, nullptr, LANGS, nullptr },
26#define LIBBUILTIN(ID, TYPE, ATTRS, HEADER, LANGS)                             \
27  { #ID, TYPE, ATTRS, HEADER, LANGS, nullptr },
28#include "clang/Basic/Builtins.def"
29};
30
31const Builtin::Info &Builtin::Context::getRecord(unsigned ID) const {
32  if (ID < Builtin::FirstTSBuiltin)
33    return BuiltinInfo[ID];
34  assert(((ID - Builtin::FirstTSBuiltin) <
35          (TSRecords.size() + AuxTSRecords.size())) &&
36         "Invalid builtin ID!");
37  if (isAuxBuiltinID(ID))
38    return AuxTSRecords[getAuxBuiltinID(ID) - Builtin::FirstTSBuiltin];
39  return TSRecords[ID - Builtin::FirstTSBuiltin];
40}
41
42void Builtin::Context::InitializeTarget(const TargetInfo &Target,
43                                        const TargetInfo *AuxTarget) {
44  assert(TSRecords.empty() && "Already initialized target?");
45  TSRecords = Target.getTargetBuiltins();
46  if (AuxTarget)
47    AuxTSRecords = AuxTarget->getTargetBuiltins();
48}
49
50bool Builtin::Context::isBuiltinFunc(llvm::StringRef FuncName) {
51  for (unsigned i = Builtin::NotBuiltin + 1; i != Builtin::FirstTSBuiltin; ++i)
52    if (FuncName.equals(BuiltinInfo[i].Name))
53      return strchr(BuiltinInfo[i].Attributes, 'f') != nullptr;
54
55  return false;
56}
57
58bool Builtin::Context::builtinIsSupported(const Builtin::Info &BuiltinInfo,
59                                          const LangOptions &LangOpts) {
60  bool BuiltinsUnsupported =
61      (LangOpts.NoBuiltin || LangOpts.isNoBuiltinFunc(BuiltinInfo.Name)) &&
62      strchr(BuiltinInfo.Attributes, 'f');
63  bool MathBuiltinsUnsupported =
64    LangOpts.NoMathBuiltin && BuiltinInfo.HeaderName &&
65    llvm::StringRef(BuiltinInfo.HeaderName).equals("math.h");
66  bool GnuModeUnsupported = !LangOpts.GNUMode && (BuiltinInfo.Langs & GNU_LANG);
67  bool MSModeUnsupported =
68      !LangOpts.MicrosoftExt && (BuiltinInfo.Langs & MS_LANG);
69  bool ObjCUnsupported = !LangOpts.ObjC && BuiltinInfo.Langs == OBJC_LANG;
70  bool OclC1Unsupported = (LangOpts.OpenCLVersion / 100) != 1 &&
71                          (BuiltinInfo.Langs & ALL_OCLC_LANGUAGES ) ==  OCLC1X_LANG;
72  bool OclC2Unsupported =
73      (LangOpts.OpenCLVersion != 200 && !LangOpts.OpenCLCPlusPlus) &&
74      (BuiltinInfo.Langs & ALL_OCLC_LANGUAGES) == OCLC20_LANG;
75  bool OclCUnsupported = !LangOpts.OpenCL &&
76                         (BuiltinInfo.Langs & ALL_OCLC_LANGUAGES);
77  bool OpenMPUnsupported = !LangOpts.OpenMP && BuiltinInfo.Langs == OMP_LANG;
78  bool CPlusPlusUnsupported =
79      !LangOpts.CPlusPlus && BuiltinInfo.Langs == CXX_LANG;
80  return !BuiltinsUnsupported && !MathBuiltinsUnsupported && !OclCUnsupported &&
81         !OclC1Unsupported && !OclC2Unsupported && !OpenMPUnsupported &&
82         !GnuModeUnsupported && !MSModeUnsupported && !ObjCUnsupported &&
83         !CPlusPlusUnsupported;
84}
85
86/// initializeBuiltins - Mark the identifiers for all the builtins with their
87/// appropriate builtin ID # and mark any non-portable builtin identifiers as
88/// such.
89void Builtin::Context::initializeBuiltins(IdentifierTable &Table,
90                                          const LangOptions& LangOpts) {
91  // Step #1: mark all target-independent builtins with their ID's.
92  for (unsigned i = Builtin::NotBuiltin+1; i != Builtin::FirstTSBuiltin; ++i)
93    if (builtinIsSupported(BuiltinInfo[i], LangOpts)) {
94      Table.get(BuiltinInfo[i].Name).setBuiltinID(i);
95    }
96
97  // Step #2: Register target-specific builtins.
98  for (unsigned i = 0, e = TSRecords.size(); i != e; ++i)
99    if (builtinIsSupported(TSRecords[i], LangOpts))
100      Table.get(TSRecords[i].Name).setBuiltinID(i + Builtin::FirstTSBuiltin);
101
102  // Step #3: Register target-specific builtins for AuxTarget.
103  for (unsigned i = 0, e = AuxTSRecords.size(); i != e; ++i)
104    Table.get(AuxTSRecords[i].Name)
105        .setBuiltinID(i + Builtin::FirstTSBuiltin + TSRecords.size());
106}
107
108void Builtin::Context::forgetBuiltin(unsigned ID, IdentifierTable &Table) {
109  Table.get(getRecord(ID).Name).setBuiltinID(0);
110}
111
112unsigned Builtin::Context::getRequiredVectorWidth(unsigned ID) const {
113  const char *WidthPos = ::strchr(getRecord(ID).Attributes, 'V');
114  if (!WidthPos)
115    return 0;
116
117  ++WidthPos;
118  assert(*WidthPos == ':' &&
119         "Vector width specifier must be followed by a ':'");
120  ++WidthPos;
121
122  char *EndPos;
123  unsigned Width = ::strtol(WidthPos, &EndPos, 10);
124  assert(*EndPos == ':' && "Vector width specific must end with a ':'");
125  return Width;
126}
127
128bool Builtin::Context::isLike(unsigned ID, unsigned &FormatIdx,
129                              bool &HasVAListArg, const char *Fmt) const {
130  assert(Fmt && "Not passed a format string");
131  assert(::strlen(Fmt) == 2 &&
132         "Format string needs to be two characters long");
133  assert(::toupper(Fmt[0]) == Fmt[1] &&
134         "Format string is not in the form \"xX\"");
135
136  const char *Like = ::strpbrk(getRecord(ID).Attributes, Fmt);
137  if (!Like)
138    return false;
139
140  HasVAListArg = (*Like == Fmt[1]);
141
142  ++Like;
143  assert(*Like == ':' && "Format specifier must be followed by a ':'");
144  ++Like;
145
146  assert(::strchr(Like, ':') && "Format specifier must end with a ':'");
147  FormatIdx = ::strtol(Like, nullptr, 10);
148  return true;
149}
150
151bool Builtin::Context::isPrintfLike(unsigned ID, unsigned &FormatIdx,
152                                    bool &HasVAListArg) {
153  return isLike(ID, FormatIdx, HasVAListArg, "pP");
154}
155
156bool Builtin::Context::isScanfLike(unsigned ID, unsigned &FormatIdx,
157                                   bool &HasVAListArg) {
158  return isLike(ID, FormatIdx, HasVAListArg, "sS");
159}
160
161bool Builtin::Context::performsCallback(unsigned ID,
162                                        SmallVectorImpl<int> &Encoding) const {
163  const char *CalleePos = ::strchr(getRecord(ID).Attributes, 'C');
164  if (!CalleePos)
165    return false;
166
167  ++CalleePos;
168  assert(*CalleePos == '<' &&
169         "Callback callee specifier must be followed by a '<'");
170  ++CalleePos;
171
172  char *EndPos;
173  int CalleeIdx = ::strtol(CalleePos, &EndPos, 10);
174  assert(CalleeIdx >= 0 && "Callee index is supposed to be positive!");
175  Encoding.push_back(CalleeIdx);
176
177  while (*EndPos == ',') {
178    const char *PayloadPos = EndPos + 1;
179
180    int PayloadIdx = ::strtol(PayloadPos, &EndPos, 10);
181    Encoding.push_back(PayloadIdx);
182  }
183
184  assert(*EndPos == '>' && "Callback callee specifier must end with a '>'");
185  return true;
186}
187
188bool Builtin::Context::canBeRedeclared(unsigned ID) const {
189  return ID == Builtin::NotBuiltin ||
190         ID == Builtin::BI__va_start ||
191         (!hasReferenceArgsOrResult(ID) &&
192          !hasCustomTypechecking(ID));
193}
194