Bug Summary

File:clang/lib/AST/TemplateBase.cpp
Warning:line 626, column 5
Storage provided to placement new is only 0 bytes, whereas the allocated type requires 32 bytes

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name TemplateBase.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/AST -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/AST -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/AST -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/AST -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/AST/TemplateBase.cpp

/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/AST/TemplateBase.cpp

1//===- TemplateBase.cpp - Common template AST class 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 common classes used throughout C++ template
10// representations.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/AST/TemplateBase.h"
15#include "clang/AST/ASTContext.h"
16#include "clang/AST/Decl.h"
17#include "clang/AST/DeclBase.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/DependenceFlags.h"
20#include "clang/AST/Expr.h"
21#include "clang/AST/ExprCXX.h"
22#include "clang/AST/PrettyPrinter.h"
23#include "clang/AST/TemplateName.h"
24#include "clang/AST/Type.h"
25#include "clang/AST/TypeLoc.h"
26#include "clang/Basic/Diagnostic.h"
27#include "clang/Basic/LLVM.h"
28#include "clang/Basic/LangOptions.h"
29#include "clang/Basic/SourceLocation.h"
30#include "llvm/ADT/APSInt.h"
31#include "llvm/ADT/FoldingSet.h"
32#include "llvm/ADT/None.h"
33#include "llvm/ADT/SmallString.h"
34#include "llvm/ADT/StringExtras.h"
35#include "llvm/ADT/StringRef.h"
36#include "llvm/Support/Casting.h"
37#include "llvm/Support/Compiler.h"
38#include "llvm/Support/ErrorHandling.h"
39#include "llvm/Support/raw_ostream.h"
40#include <cassert>
41#include <cstddef>
42#include <cstdint>
43#include <cstring>
44
45using namespace clang;
46
47/// Print a template integral argument value.
48///
49/// \param TemplArg the TemplateArgument instance to print.
50///
51/// \param Out the raw_ostream instance to use for printing.
52///
53/// \param Policy the printing policy for EnumConstantDecl printing.
54///
55/// \param IncludeType If set, ensure that the type of the expression printed
56/// matches the type of the template argument.
57static void printIntegral(const TemplateArgument &TemplArg, raw_ostream &Out,
58 const PrintingPolicy &Policy, bool IncludeType) {
59 const Type *T = TemplArg.getIntegralType().getTypePtr();
60 const llvm::APSInt &Val = TemplArg.getAsIntegral();
61
62 if (const EnumType *ET = T->getAs<EnumType>()) {
63 for (const EnumConstantDecl* ECD : ET->getDecl()->enumerators()) {
64 // In Sema::CheckTemplateArugment, enum template arguments value are
65 // extended to the size of the integer underlying the enum type. This
66 // may create a size difference between the enum value and template
67 // argument value, requiring isSameValue here instead of operator==.
68 if (llvm::APSInt::isSameValue(ECD->getInitVal(), Val)) {
69 ECD->printQualifiedName(Out, Policy);
70 return;
71 }
72 }
73 }
74
75 if (Policy.MSVCFormatting)
76 IncludeType = false;
77
78 if (T->isBooleanType()) {
79 if (!Policy.MSVCFormatting)
80 Out << (Val.getBoolValue() ? "true" : "false");
81 else
82 Out << Val;
83 } else if (T->isCharType()) {
84 if (IncludeType) {
85 if (T->isSpecificBuiltinType(BuiltinType::SChar))
86 Out << "(signed char)";
87 else if (T->isSpecificBuiltinType(BuiltinType::UChar))
88 Out << "(unsigned char)";
89 }
90 CharacterLiteral::print(Val.getZExtValue(), CharacterLiteral::Ascii, Out);
91 } else if (T->isAnyCharacterType() && !Policy.MSVCFormatting) {
92 CharacterLiteral::CharacterKind Kind;
93 if (T->isWideCharType())
94 Kind = CharacterLiteral::Wide;
95 else if (T->isChar8Type())
96 Kind = CharacterLiteral::UTF8;
97 else if (T->isChar16Type())
98 Kind = CharacterLiteral::UTF16;
99 else if (T->isChar32Type())
100 Kind = CharacterLiteral::UTF32;
101 else
102 Kind = CharacterLiteral::Ascii;
103 CharacterLiteral::print(Val.getExtValue(), Kind, Out);
104 } else if (IncludeType) {
105 if (const auto *BT = T->getAs<BuiltinType>()) {
106 switch (BT->getKind()) {
107 case BuiltinType::ULongLong:
108 Out << Val << "ULL";
109 break;
110 case BuiltinType::LongLong:
111 Out << Val << "LL";
112 break;
113 case BuiltinType::ULong:
114 Out << Val << "UL";
115 break;
116 case BuiltinType::Long:
117 Out << Val << "L";
118 break;
119 case BuiltinType::UInt:
120 Out << Val << "U";
121 break;
122 case BuiltinType::Int:
123 Out << Val;
124 break;
125 default:
126 Out << "(" << T->getCanonicalTypeInternal().getAsString(Policy) << ")"
127 << Val;
128 break;
129 }
130 } else
131 Out << "(" << T->getCanonicalTypeInternal().getAsString(Policy) << ")"
132 << Val;
133 } else
134 Out << Val;
135}
136
137static unsigned getArrayDepth(QualType type) {
138 unsigned count = 0;
139 while (const auto *arrayType = type->getAsArrayTypeUnsafe()) {
140 count++;
141 type = arrayType->getElementType();
142 }
143 return count;
144}
145
146static bool needsAmpersandOnTemplateArg(QualType paramType, QualType argType) {
147 // Generally, if the parameter type is a pointer, we must be taking the
148 // address of something and need a &. However, if the argument is an array,
149 // this could be implicit via array-to-pointer decay.
150 if (!paramType->isPointerType())
151 return paramType->isMemberPointerType();
152 if (argType->isArrayType())
153 return getArrayDepth(argType) == getArrayDepth(paramType->getPointeeType());
154 return true;
155}
156
157//===----------------------------------------------------------------------===//
158// TemplateArgument Implementation
159//===----------------------------------------------------------------------===//
160
161TemplateArgument::TemplateArgument(ASTContext &Ctx, const llvm::APSInt &Value,
162 QualType Type) {
163 Integer.Kind = Integral;
164 // Copy the APSInt value into our decomposed form.
165 Integer.BitWidth = Value.getBitWidth();
166 Integer.IsUnsigned = Value.isUnsigned();
167 // If the value is large, we have to get additional memory from the ASTContext
168 unsigned NumWords = Value.getNumWords();
169 if (NumWords > 1) {
170 void *Mem = Ctx.Allocate(NumWords * sizeof(uint64_t));
171 std::memcpy(Mem, Value.getRawData(), NumWords * sizeof(uint64_t));
172 Integer.pVal = static_cast<uint64_t *>(Mem);
173 } else {
174 Integer.VAL = Value.getZExtValue();
175 }
176
177 Integer.Type = Type.getAsOpaquePtr();
178}
179
180TemplateArgument
181TemplateArgument::CreatePackCopy(ASTContext &Context,
182 ArrayRef<TemplateArgument> Args) {
183 if (Args.empty())
184 return getEmptyPack();
185
186 return TemplateArgument(Args.copy(Context));
187}
188
189TemplateArgumentDependence TemplateArgument::getDependence() const {
190 auto Deps = TemplateArgumentDependence::None;
191 switch (getKind()) {
192 case Null:
193 llvm_unreachable("Should not have a NULL template argument")__builtin_unreachable();
194
195 case Type:
196 Deps = toTemplateArgumentDependence(getAsType()->getDependence());
197 if (isa<PackExpansionType>(getAsType()))
198 Deps |= TemplateArgumentDependence::Dependent;
199 return Deps;
200
201 case Template:
202 return toTemplateArgumentDependence(getAsTemplate().getDependence());
203
204 case TemplateExpansion:
205 return TemplateArgumentDependence::Dependent |
206 TemplateArgumentDependence::Instantiation;
207
208 case Declaration: {
209 auto *DC = dyn_cast<DeclContext>(getAsDecl());
210 if (!DC)
211 DC = getAsDecl()->getDeclContext();
212 if (DC->isDependentContext())
213 Deps = TemplateArgumentDependence::Dependent |
214 TemplateArgumentDependence::Instantiation;
215 return Deps;
216 }
217
218 case NullPtr:
219 case Integral:
220 return TemplateArgumentDependence::None;
221
222 case Expression:
223 Deps = toTemplateArgumentDependence(getAsExpr()->getDependence());
224 if (isa<PackExpansionExpr>(getAsExpr()))
225 Deps |= TemplateArgumentDependence::Dependent |
226 TemplateArgumentDependence::Instantiation;
227 return Deps;
228
229 case Pack:
230 for (const auto &P : pack_elements())
231 Deps |= P.getDependence();
232 return Deps;
233 }
234 llvm_unreachable("unhandled ArgKind")__builtin_unreachable();
235}
236
237bool TemplateArgument::isDependent() const {
238 return getDependence() & TemplateArgumentDependence::Dependent;
239}
240
241bool TemplateArgument::isInstantiationDependent() const {
242 return getDependence() & TemplateArgumentDependence::Instantiation;
243}
244
245bool TemplateArgument::isPackExpansion() const {
246 switch (getKind()) {
247 case Null:
248 case Declaration:
249 case Integral:
250 case Pack:
251 case Template:
252 case NullPtr:
253 return false;
254
255 case TemplateExpansion:
256 return true;
257
258 case Type:
259 return isa<PackExpansionType>(getAsType());
260
261 case Expression:
262 return isa<PackExpansionExpr>(getAsExpr());
263 }
264
265 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
266}
267
268bool TemplateArgument::containsUnexpandedParameterPack() const {
269 return getDependence() & TemplateArgumentDependence::UnexpandedPack;
270}
271
272Optional<unsigned> TemplateArgument::getNumTemplateExpansions() const {
273 assert(getKind() == TemplateExpansion)(static_cast<void> (0));
274 if (TemplateArg.NumExpansions)
275 return TemplateArg.NumExpansions - 1;
276
277 return None;
278}
279
280QualType TemplateArgument::getNonTypeTemplateArgumentType() const {
281 switch (getKind()) {
282 case TemplateArgument::Null:
283 case TemplateArgument::Type:
284 case TemplateArgument::Template:
285 case TemplateArgument::TemplateExpansion:
286 case TemplateArgument::Pack:
287 return QualType();
288
289 case TemplateArgument::Integral:
290 return getIntegralType();
291
292 case TemplateArgument::Expression:
293 return getAsExpr()->getType();
294
295 case TemplateArgument::Declaration:
296 return getParamTypeForDecl();
297
298 case TemplateArgument::NullPtr:
299 return getNullPtrType();
300 }
301
302 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
303}
304
305void TemplateArgument::Profile(llvm::FoldingSetNodeID &ID,
306 const ASTContext &Context) const {
307 ID.AddInteger(getKind());
308 switch (getKind()) {
309 case Null:
310 break;
311
312 case Type:
313 getAsType().Profile(ID);
314 break;
315
316 case NullPtr:
317 getNullPtrType().Profile(ID);
318 break;
319
320 case Declaration:
321 getParamTypeForDecl().Profile(ID);
322 ID.AddPointer(getAsDecl()? getAsDecl()->getCanonicalDecl() : nullptr);
323 break;
324
325 case Template:
326 case TemplateExpansion: {
327 TemplateName Template = getAsTemplateOrTemplatePattern();
328 if (TemplateTemplateParmDecl *TTP
329 = dyn_cast_or_null<TemplateTemplateParmDecl>(
330 Template.getAsTemplateDecl())) {
331 ID.AddBoolean(true);
332 ID.AddInteger(TTP->getDepth());
333 ID.AddInteger(TTP->getPosition());
334 ID.AddBoolean(TTP->isParameterPack());
335 } else {
336 ID.AddBoolean(false);
337 ID.AddPointer(Context.getCanonicalTemplateName(Template)
338 .getAsVoidPointer());
339 }
340 break;
341 }
342
343 case Integral:
344 getAsIntegral().Profile(ID);
345 getIntegralType().Profile(ID);
346 break;
347
348 case Expression:
349 getAsExpr()->Profile(ID, Context, true);
350 break;
351
352 case Pack:
353 ID.AddInteger(Args.NumArgs);
354 for (unsigned I = 0; I != Args.NumArgs; ++I)
355 Args.Args[I].Profile(ID, Context);
356 }
357}
358
359bool TemplateArgument::structurallyEquals(const TemplateArgument &Other) const {
360 if (getKind() != Other.getKind()) return false;
361
362 switch (getKind()) {
363 case Null:
364 case Type:
365 case Expression:
366 case NullPtr:
367 return TypeOrValue.V == Other.TypeOrValue.V;
368
369 case Template:
370 case TemplateExpansion:
371 return TemplateArg.Name == Other.TemplateArg.Name &&
372 TemplateArg.NumExpansions == Other.TemplateArg.NumExpansions;
373
374 case Declaration:
375 return getAsDecl() == Other.getAsDecl();
376
377 case Integral:
378 return getIntegralType() == Other.getIntegralType() &&
379 getAsIntegral() == Other.getAsIntegral();
380
381 case Pack:
382 if (Args.NumArgs != Other.Args.NumArgs) return false;
383 for (unsigned I = 0, E = Args.NumArgs; I != E; ++I)
384 if (!Args.Args[I].structurallyEquals(Other.Args.Args[I]))
385 return false;
386 return true;
387 }
388
389 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
390}
391
392TemplateArgument TemplateArgument::getPackExpansionPattern() const {
393 assert(isPackExpansion())(static_cast<void> (0));
394
395 switch (getKind()) {
396 case Type:
397 return getAsType()->castAs<PackExpansionType>()->getPattern();
398
399 case Expression:
400 return cast<PackExpansionExpr>(getAsExpr())->getPattern();
401
402 case TemplateExpansion:
403 return TemplateArgument(getAsTemplateOrTemplatePattern());
404
405 case Declaration:
406 case Integral:
407 case Pack:
408 case Null:
409 case Template:
410 case NullPtr:
411 return TemplateArgument();
412 }
413
414 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
415}
416
417void TemplateArgument::print(const PrintingPolicy &Policy, raw_ostream &Out,
418 bool IncludeType) const {
419
420 switch (getKind()) {
421 case Null:
422 Out << "(no value)";
423 break;
424
425 case Type: {
426 PrintingPolicy SubPolicy(Policy);
427 SubPolicy.SuppressStrongLifetime = true;
428 getAsType().print(Out, SubPolicy);
429 break;
430 }
431
432 case Declaration: {
433 // FIXME: Include the type if it's not obvious from the context.
434 NamedDecl *ND = getAsDecl();
435 if (getParamTypeForDecl()->isRecordType()) {
436 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(ND)) {
437 TPO->printAsInit(Out);
438 break;
439 }
440 }
441 if (auto *VD = dyn_cast<ValueDecl>(ND)) {
442 if (needsAmpersandOnTemplateArg(getParamTypeForDecl(), VD->getType()))
443 Out << "&";
444 }
445 ND->printQualifiedName(Out);
446 break;
447 }
448
449 case NullPtr:
450 // FIXME: Include the type if it's not obvious from the context.
451 Out << "nullptr";
452 break;
453
454 case Template:
455 getAsTemplate().print(Out, Policy, TemplateName::Qualified::Fully);
456 break;
457
458 case TemplateExpansion:
459 getAsTemplateOrTemplatePattern().print(Out, Policy);
460 Out << "...";
461 break;
462
463 case Integral:
464 printIntegral(*this, Out, Policy, IncludeType);
465 break;
466
467 case Expression:
468 getAsExpr()->printPretty(Out, nullptr, Policy);
469 break;
470
471 case Pack:
472 Out << "<";
473 bool First = true;
474 for (const auto &P : pack_elements()) {
475 if (First)
476 First = false;
477 else
478 Out << ", ";
479
480 P.print(Policy, Out, IncludeType);
481 }
482 Out << ">";
483 break;
484 }
485}
486
487void TemplateArgument::dump(raw_ostream &Out) const {
488 LangOptions LO; // FIXME! see also TemplateName::dump().
489 LO.CPlusPlus = true;
490 LO.Bool = true;
491 print(PrintingPolicy(LO), Out, /*IncludeType*/ true);
492}
493
494LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void TemplateArgument::dump() const { dump(llvm::errs()); }
495
496//===----------------------------------------------------------------------===//
497// TemplateArgumentLoc Implementation
498//===----------------------------------------------------------------------===//
499
500SourceRange TemplateArgumentLoc::getSourceRange() const {
501 switch (Argument.getKind()) {
502 case TemplateArgument::Expression:
503 return getSourceExpression()->getSourceRange();
504
505 case TemplateArgument::Declaration:
506 return getSourceDeclExpression()->getSourceRange();
507
508 case TemplateArgument::NullPtr:
509 return getSourceNullPtrExpression()->getSourceRange();
510
511 case TemplateArgument::Type:
512 if (TypeSourceInfo *TSI = getTypeSourceInfo())
513 return TSI->getTypeLoc().getSourceRange();
514 else
515 return SourceRange();
516
517 case TemplateArgument::Template:
518 if (getTemplateQualifierLoc())
519 return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
520 getTemplateNameLoc());
521 return SourceRange(getTemplateNameLoc());
522
523 case TemplateArgument::TemplateExpansion:
524 if (getTemplateQualifierLoc())
525 return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
526 getTemplateEllipsisLoc());
527 return SourceRange(getTemplateNameLoc(), getTemplateEllipsisLoc());
528
529 case TemplateArgument::Integral:
530 return getSourceIntegralExpression()->getSourceRange();
531
532 case TemplateArgument::Pack:
533 case TemplateArgument::Null:
534 return SourceRange();
535 }
536
537 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
538}
539
540template <typename T>
541static const T &DiagTemplateArg(const T &DB, const TemplateArgument &Arg) {
542 switch (Arg.getKind()) {
543 case TemplateArgument::Null:
544 // This is bad, but not as bad as crashing because of argument
545 // count mismatches.
546 return DB << "(null template argument)";
547
548 case TemplateArgument::Type:
549 return DB << Arg.getAsType();
550
551 case TemplateArgument::Declaration:
552 return DB << Arg.getAsDecl();
553
554 case TemplateArgument::NullPtr:
555 return DB << "nullptr";
556
557 case TemplateArgument::Integral:
558 return DB << toString(Arg.getAsIntegral(), 10);
559
560 case TemplateArgument::Template:
561 return DB << Arg.getAsTemplate();
562
563 case TemplateArgument::TemplateExpansion:
564 return DB << Arg.getAsTemplateOrTemplatePattern() << "...";
565
566 case TemplateArgument::Expression: {
567 // This shouldn't actually ever happen, so it's okay that we're
568 // regurgitating an expression here.
569 // FIXME: We're guessing at LangOptions!
570 SmallString<32> Str;
571 llvm::raw_svector_ostream OS(Str);
572 LangOptions LangOpts;
573 LangOpts.CPlusPlus = true;
574 PrintingPolicy Policy(LangOpts);
575 Arg.getAsExpr()->printPretty(OS, nullptr, Policy);
576 return DB << OS.str();
577 }
578
579 case TemplateArgument::Pack: {
580 // FIXME: We're guessing at LangOptions!
581 SmallString<32> Str;
582 llvm::raw_svector_ostream OS(Str);
583 LangOptions LangOpts;
584 LangOpts.CPlusPlus = true;
585 PrintingPolicy Policy(LangOpts);
586 Arg.print(Policy, OS, /*IncludeType*/ true);
587 return DB << OS.str();
588 }
589 }
590
591 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
592}
593
594const StreamingDiagnostic &clang::operator<<(const StreamingDiagnostic &DB,
595 const TemplateArgument &Arg) {
596 return DiagTemplateArg(DB, Arg);
597}
598
599clang::TemplateArgumentLocInfo::TemplateArgumentLocInfo(
600 ASTContext &Ctx, NestedNameSpecifierLoc QualifierLoc,
601 SourceLocation TemplateNameLoc, SourceLocation EllipsisLoc) {
602 TemplateTemplateArgLocInfo *Template = new (Ctx) TemplateTemplateArgLocInfo;
603 Template->Qualifier = QualifierLoc.getNestedNameSpecifier();
604 Template->QualifierLocData = QualifierLoc.getOpaqueData();
605 Template->TemplateNameLoc = TemplateNameLoc;
606 Template->EllipsisLoc = EllipsisLoc;
607 Pointer = Template;
608}
609
610const ASTTemplateArgumentListInfo *
611ASTTemplateArgumentListInfo::Create(const ASTContext &C,
612 const TemplateArgumentListInfo &List) {
613 std::size_t size = totalSizeToAlloc<TemplateArgumentLoc>(List.size());
614 void *Mem = C.Allocate(size, alignof(ASTTemplateArgumentListInfo));
615 return new (Mem) ASTTemplateArgumentListInfo(List);
1
Calling constructor for 'ASTTemplateArgumentListInfo'
616}
617
618ASTTemplateArgumentListInfo::ASTTemplateArgumentListInfo(
619 const TemplateArgumentListInfo &Info) {
620 LAngleLoc = Info.getLAngleLoc();
621 RAngleLoc = Info.getRAngleLoc();
622 NumTemplateArgs = Info.size();
623
624 TemplateArgumentLoc *ArgBuffer = getTrailingObjects<TemplateArgumentLoc>();
2
Calling 'TrailingObjects::getTrailingObjects'
11
Returning from 'TrailingObjects::getTrailingObjects'
12
'ArgBuffer' initialized here
625 for (unsigned i = 0; i != NumTemplateArgs; ++i)
13
Assuming 'i' is not equal to field 'NumTemplateArgs'
14
Loop condition is true. Entering loop body
626 new (&ArgBuffer[i]) TemplateArgumentLoc(Info[i]);
15
Storage provided to placement new is only 0 bytes, whereas the allocated type requires 32 bytes
627}
628
629void ASTTemplateKWAndArgsInfo::initializeFrom(
630 SourceLocation TemplateKWLoc, const TemplateArgumentListInfo &Info,
631 TemplateArgumentLoc *OutArgArray) {
632 this->TemplateKWLoc = TemplateKWLoc;
633 LAngleLoc = Info.getLAngleLoc();
634 RAngleLoc = Info.getRAngleLoc();
635 NumTemplateArgs = Info.size();
636
637 for (unsigned i = 0; i != NumTemplateArgs; ++i)
638 new (&OutArgArray[i]) TemplateArgumentLoc(Info[i]);
639}
640
641void ASTTemplateKWAndArgsInfo::initializeFrom(SourceLocation TemplateKWLoc) {
642 assert(TemplateKWLoc.isValid())(static_cast<void> (0));
643 LAngleLoc = SourceLocation();
644 RAngleLoc = SourceLocation();
645 this->TemplateKWLoc = TemplateKWLoc;
646 NumTemplateArgs = 0;
647}
648
649void ASTTemplateKWAndArgsInfo::initializeFrom(
650 SourceLocation TemplateKWLoc, const TemplateArgumentListInfo &Info,
651 TemplateArgumentLoc *OutArgArray, TemplateArgumentDependence &Deps) {
652 this->TemplateKWLoc = TemplateKWLoc;
653 LAngleLoc = Info.getLAngleLoc();
654 RAngleLoc = Info.getRAngleLoc();
655 NumTemplateArgs = Info.size();
656
657 for (unsigned i = 0; i != NumTemplateArgs; ++i) {
658 Deps |= Info[i].getArgument().getDependence();
659
660 new (&OutArgArray[i]) TemplateArgumentLoc(Info[i]);
661 }
662}
663
664void ASTTemplateKWAndArgsInfo::copyInto(const TemplateArgumentLoc *ArgArray,
665 TemplateArgumentListInfo &Info) const {
666 Info.setLAngleLoc(LAngleLoc);
667 Info.setRAngleLoc(RAngleLoc);
668 for (unsigned I = 0; I != NumTemplateArgs; ++I)
669 Info.addArgument(ArgArray[I]);
670}

/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include/llvm/Support/TrailingObjects.h

1//===--- TrailingObjects.h - Variable-length classes ------------*- 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/// This header defines support for implementing classes that have
11/// some trailing object (or arrays of objects) appended to them. The
12/// main purpose is to make it obvious where this idiom is being used,
13/// and to make the usage more idiomatic and more difficult to get
14/// wrong.
15///
16/// The TrailingObject template abstracts away the reinterpret_cast,
17/// pointer arithmetic, and size calculations used for the allocation
18/// and access of appended arrays of objects, and takes care that they
19/// are all allocated at their required alignment. Additionally, it
20/// ensures that the base type is final -- deriving from a class that
21/// expects data appended immediately after it is typically not safe.
22///
23/// Users are expected to derive from this template, and provide
24/// numTrailingObjects implementations for each trailing type except
25/// the last, e.g. like this sample:
26///
27/// \code
28/// class VarLengthObj : private TrailingObjects<VarLengthObj, int, double> {
29/// friend TrailingObjects;
30///
31/// unsigned NumInts, NumDoubles;
32/// size_t numTrailingObjects(OverloadToken<int>) const { return NumInts; }
33/// };
34/// \endcode
35///
36/// You can access the appended arrays via 'getTrailingObjects', and
37/// determine the size needed for allocation via
38/// 'additionalSizeToAlloc' and 'totalSizeToAlloc'.
39///
40/// All the methods implemented by this class are are intended for use
41/// by the implementation of the class, not as part of its interface
42/// (thus, private inheritance is suggested).
43///
44//===----------------------------------------------------------------------===//
45
46#ifndef LLVM_SUPPORT_TRAILINGOBJECTS_H
47#define LLVM_SUPPORT_TRAILINGOBJECTS_H
48
49#include "llvm/Support/AlignOf.h"
50#include "llvm/Support/Alignment.h"
51#include "llvm/Support/Compiler.h"
52#include "llvm/Support/MathExtras.h"
53#include "llvm/Support/type_traits.h"
54#include <new>
55#include <type_traits>
56
57namespace llvm {
58
59namespace trailing_objects_internal {
60/// Helper template to calculate the max alignment requirement for a set of
61/// objects.
62template <typename First, typename... Rest> class AlignmentCalcHelper {
63private:
64 enum {
65 FirstAlignment = alignof(First),
66 RestAlignment = AlignmentCalcHelper<Rest...>::Alignment,
67 };
68
69public:
70 enum {
71 Alignment = FirstAlignment > RestAlignment ? FirstAlignment : RestAlignment
72 };
73};
74
75template <typename First> class AlignmentCalcHelper<First> {
76public:
77 enum { Alignment = alignof(First) };
78};
79
80/// The base class for TrailingObjects* classes.
81class TrailingObjectsBase {
82protected:
83 /// OverloadToken's purpose is to allow specifying function overloads
84 /// for different types, without actually taking the types as
85 /// parameters. (Necessary because member function templates cannot
86 /// be specialized, so overloads must be used instead of
87 /// specialization.)
88 template <typename T> struct OverloadToken {};
89};
90
91// Just a little helper for transforming a type pack into the same
92// number of a different type. e.g.:
93// ExtractSecondType<Foo..., int>::type
94template <typename Ty1, typename Ty2> struct ExtractSecondType {
95 typedef Ty2 type;
96};
97
98// TrailingObjectsImpl is somewhat complicated, because it is a
99// recursively inheriting template, in order to handle the template
100// varargs. Each level of inheritance picks off a single trailing type
101// then recurses on the rest. The "Align", "BaseTy", and
102// "TopTrailingObj" arguments are passed through unchanged through the
103// recursion. "PrevTy" is, at each level, the type handled by the
104// level right above it.
105
106template <int Align, typename BaseTy, typename TopTrailingObj, typename PrevTy,
107 typename... MoreTys>
108class TrailingObjectsImpl {
109 // The main template definition is never used -- the two
110 // specializations cover all possibilities.
111};
112
113template <int Align, typename BaseTy, typename TopTrailingObj, typename PrevTy,
114 typename NextTy, typename... MoreTys>
115class TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, PrevTy, NextTy,
116 MoreTys...>
117 : public TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, NextTy,
118 MoreTys...> {
119
120 typedef TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, NextTy, MoreTys...>
121 ParentType;
122
123 struct RequiresRealignment {
124 static const bool value = alignof(PrevTy) < alignof(NextTy);
125 };
126
127 static constexpr bool requiresRealignment() {
128 return RequiresRealignment::value;
129 }
130
131protected:
132 // Ensure the inherited getTrailingObjectsImpl is not hidden.
133 using ParentType::getTrailingObjectsImpl;
134
135 // These two functions are helper functions for
136 // TrailingObjects::getTrailingObjects. They recurse to the left --
137 // the result for each type in the list of trailing types depends on
138 // the result of calling the function on the type to the
139 // left. However, the function for the type to the left is
140 // implemented by a *subclass* of this class, so we invoke it via
141 // the TopTrailingObj, which is, via the
142 // curiously-recurring-template-pattern, the most-derived type in
143 // this recursion, and thus, contains all the overloads.
144 static const NextTy *
145 getTrailingObjectsImpl(const BaseTy *Obj,
146 TrailingObjectsBase::OverloadToken<NextTy>) {
147 auto *Ptr = TopTrailingObj::getTrailingObjectsImpl(
148 Obj, TrailingObjectsBase::OverloadToken<PrevTy>()) +
149 TopTrailingObj::callNumTrailingObjects(
150 Obj, TrailingObjectsBase::OverloadToken<PrevTy>());
151
152 if (requiresRealignment())
153 return reinterpret_cast<const NextTy *>(
154 alignAddr(Ptr, Align::Of<NextTy>()));
155 else
156 return reinterpret_cast<const NextTy *>(Ptr);
157 }
158
159 static NextTy *
160 getTrailingObjectsImpl(BaseTy *Obj,
161 TrailingObjectsBase::OverloadToken<NextTy>) {
162 auto *Ptr = TopTrailingObj::getTrailingObjectsImpl(
6
'Ptr' initialized here
163 Obj, TrailingObjectsBase::OverloadToken<PrevTy>()) +
5
Passing value via 1st parameter 'Obj'
164 TopTrailingObj::callNumTrailingObjects(
165 Obj, TrailingObjectsBase::OverloadToken<PrevTy>());
166
167 if (requiresRealignment())
7
Taking false branch
168 return reinterpret_cast<NextTy *>(alignAddr(Ptr, Align::Of<NextTy>()));
169 else
170 return reinterpret_cast<NextTy *>(Ptr);
8
Returning pointer (loaded from 'Ptr')
171 }
172
173 // Helper function for TrailingObjects::additionalSizeToAlloc: this
174 // function recurses to superclasses, each of which requires one
175 // fewer size_t argument, and adds its own size.
176 static constexpr size_t additionalSizeToAllocImpl(
177 size_t SizeSoFar, size_t Count1,
178 typename ExtractSecondType<MoreTys, size_t>::type... MoreCounts) {
179 return ParentType::additionalSizeToAllocImpl(
180 (requiresRealignment() ? llvm::alignTo<alignof(NextTy)>(SizeSoFar)
181 : SizeSoFar) +
182 sizeof(NextTy) * Count1,
183 MoreCounts...);
184 }
185};
186
187// The base case of the TrailingObjectsImpl inheritance recursion,
188// when there's no more trailing types.
189template <int Align, typename BaseTy, typename TopTrailingObj, typename PrevTy>
190class alignas(Align) TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, PrevTy>
191 : public TrailingObjectsBase {
192protected:
193 // This is a dummy method, only here so the "using" doesn't fail --
194 // it will never be called, because this function recurses backwards
195 // up the inheritance chain to subclasses.
196 static void getTrailingObjectsImpl();
197
198 static constexpr size_t additionalSizeToAllocImpl(size_t SizeSoFar) {
199 return SizeSoFar;
200 }
201
202 template <bool CheckAlignment> static void verifyTrailingObjectsAlignment() {}
203};
204
205} // end namespace trailing_objects_internal
206
207// Finally, the main type defined in this file, the one intended for users...
208
209/// See the file comment for details on the usage of the
210/// TrailingObjects type.
211template <typename BaseTy, typename... TrailingTys>
212class TrailingObjects : private trailing_objects_internal::TrailingObjectsImpl<
213 trailing_objects_internal::AlignmentCalcHelper<
214 TrailingTys...>::Alignment,
215 BaseTy, TrailingObjects<BaseTy, TrailingTys...>,
216 BaseTy, TrailingTys...> {
217
218 template <int A, typename B, typename T, typename P, typename... M>
219 friend class trailing_objects_internal::TrailingObjectsImpl;
220
221 template <typename... Tys> class Foo {};
222
223 typedef trailing_objects_internal::TrailingObjectsImpl<
224 trailing_objects_internal::AlignmentCalcHelper<TrailingTys...>::Alignment,
225 BaseTy, TrailingObjects<BaseTy, TrailingTys...>, BaseTy, TrailingTys...>
226 ParentType;
227 using TrailingObjectsBase = trailing_objects_internal::TrailingObjectsBase;
228
229 using ParentType::getTrailingObjectsImpl;
230
231 // This function contains only a static_assert BaseTy is final. The
232 // static_assert must be in a function, and not at class-level
233 // because BaseTy isn't complete at class instantiation time, but
234 // will be by the time this function is instantiated.
235 static void verifyTrailingObjectsAssertions() {
236 static_assert(std::is_final<BaseTy>(), "BaseTy must be final.");
237 }
238
239 // These two methods are the base of the recursion for this method.
240 static const BaseTy *
241 getTrailingObjectsImpl(const BaseTy *Obj,
242 TrailingObjectsBase::OverloadToken<BaseTy>) {
243 return Obj;
244 }
245
246 static BaseTy *
247 getTrailingObjectsImpl(BaseTy *Obj,
248 TrailingObjectsBase::OverloadToken<BaseTy>) {
249 return Obj;
250 }
251
252 // callNumTrailingObjects simply calls numTrailingObjects on the
253 // provided Obj -- except when the type being queried is BaseTy
254 // itself. There is always only one of the base object, so that case
255 // is handled here. (An additional benefit of indirecting through
256 // this function is that consumers only say "friend
257 // TrailingObjects", and thus, only this class itself can call the
258 // numTrailingObjects function.)
259 static size_t
260 callNumTrailingObjects(const BaseTy *Obj,
261 TrailingObjectsBase::OverloadToken<BaseTy>) {
262 return 1;
263 }
264
265 template <typename T>
266 static size_t callNumTrailingObjects(const BaseTy *Obj,
267 TrailingObjectsBase::OverloadToken<T>) {
268 return Obj->numTrailingObjects(TrailingObjectsBase::OverloadToken<T>());
269 }
270
271public:
272 // Make this (privately inherited) member public.
273#ifndef _MSC_VER
274 using ParentType::OverloadToken;
275#else
276 // An MSVC bug prevents the above from working, (last tested at CL version
277 // 19.28). "Class5" in TrailingObjectsTest.cpp tests the problematic case.
278 template <typename T>
279 using OverloadToken = typename ParentType::template OverloadToken<T>;
280#endif
281
282 /// Returns a pointer to the trailing object array of the given type
283 /// (which must be one of those specified in the class template). The
284 /// array may have zero or more elements in it.
285 template <typename T> const T *getTrailingObjects() const {
286 verifyTrailingObjectsAssertions();
287 // Forwards to an impl function with overloads, since member
288 // function templates can't be specialized.
289 return this->getTrailingObjectsImpl(
290 static_cast<const BaseTy *>(this),
291 TrailingObjectsBase::OverloadToken<T>());
292 }
293
294 /// Returns a pointer to the trailing object array of the given type
295 /// (which must be one of those specified in the class template). The
296 /// array may have zero or more elements in it.
297 template <typename T> T *getTrailingObjects() {
298 verifyTrailingObjectsAssertions();
299 // Forwards to an impl function with overloads, since member
300 // function templates can't be specialized.
301 return this->getTrailingObjectsImpl(
4
Calling 'TrailingObjectsImpl::getTrailingObjectsImpl'
9
Returning from 'TrailingObjectsImpl::getTrailingObjectsImpl'
10
Returning pointer
302 static_cast<BaseTy *>(this), TrailingObjectsBase::OverloadToken<T>());
3
Passing value via 1st parameter 'Obj'
303 }
304
305 /// Returns the size of the trailing data, if an object were
306 /// allocated with the given counts (The counts are in the same order
307 /// as the template arguments). This does not include the size of the
308 /// base object. The template arguments must be the same as those
309 /// used in the class; they are supplied here redundantly only so
310 /// that it's clear what the counts are counting in callers.
311 template <typename... Tys>
312 static constexpr std::enable_if_t<
313 std::is_same<Foo<TrailingTys...>, Foo<Tys...>>::value, size_t>
314 additionalSizeToAlloc(typename trailing_objects_internal::ExtractSecondType<
315 TrailingTys, size_t>::type... Counts) {
316 return ParentType::additionalSizeToAllocImpl(0, Counts...);
317 }
318
319 /// Returns the total size of an object if it were allocated with the
320 /// given trailing object counts. This is the same as
321 /// additionalSizeToAlloc, except it *does* include the size of the base
322 /// object.
323 template <typename... Tys>
324 static constexpr std::enable_if_t<
325 std::is_same<Foo<TrailingTys...>, Foo<Tys...>>::value, size_t>
326 totalSizeToAlloc(typename trailing_objects_internal::ExtractSecondType<
327 TrailingTys, size_t>::type... Counts) {
328 return sizeof(BaseTy) + ParentType::additionalSizeToAllocImpl(0, Counts...);
329 }
330
331 TrailingObjects() = default;
332 TrailingObjects(const TrailingObjects &) = delete;
333 TrailingObjects(TrailingObjects &&) = delete;
334 TrailingObjects &operator=(const TrailingObjects &) = delete;
335 TrailingObjects &operator=(TrailingObjects &&) = delete;
336
337 /// A type where its ::with_counts template member has a ::type member
338 /// suitable for use as uninitialized storage for an object with the given
339 /// trailing object counts. The template arguments are similar to those
340 /// of additionalSizeToAlloc.
341 ///
342 /// Use with FixedSizeStorageOwner, e.g.:
343 ///
344 /// \code{.cpp}
345 ///
346 /// MyObj::FixedSizeStorage<void *>::with_counts<1u>::type myStackObjStorage;
347 /// MyObj::FixedSizeStorageOwner
348 /// myStackObjOwner(new ((void *)&myStackObjStorage) MyObj);
349 /// MyObj *const myStackObjPtr = myStackObjOwner.get();
350 ///
351 /// \endcode
352 template <typename... Tys> struct FixedSizeStorage {
353 template <size_t... Counts> struct with_counts {
354 enum { Size = totalSizeToAlloc<Tys...>(Counts...) };
355 struct type {
356 alignas(BaseTy) char buffer[Size];
357 };
358 };
359 };
360
361 /// A type that acts as the owner for an object placed into fixed storage.
362 class FixedSizeStorageOwner {
363 public:
364 FixedSizeStorageOwner(BaseTy *p) : p(p) {}
365 ~FixedSizeStorageOwner() {
366 assert(p && "FixedSizeStorageOwner owns null?")(static_cast<void> (0));
367 p->~BaseTy();
368 }
369
370 BaseTy *get() { return p; }
371 const BaseTy *get() const { return p; }
372
373 private:
374 FixedSizeStorageOwner(const FixedSizeStorageOwner &) = delete;
375 FixedSizeStorageOwner(FixedSizeStorageOwner &&) = delete;
376 FixedSizeStorageOwner &operator=(const FixedSizeStorageOwner &) = delete;
377 FixedSizeStorageOwner &operator=(FixedSizeStorageOwner &&) = delete;
378
379 BaseTy *const p;
380 };
381};
382
383} // end namespace llvm
384
385#endif