Bug Summary

File:clang/lib/Sema/SemaCoroutine.cpp
Warning:line 664, column 13
Called C++ object pointer is null

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 SemaCoroutine.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 -fno-split-dwarf-inlining -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-12/lib/clang/12.0.0 -D CLANG_VENDOR="Debian " -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/build-llvm/tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/include -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/build-llvm/include -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-12/lib/clang/12.0.0/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-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/build-llvm/tools/clang/lib/Sema -fdebug-prefix-map=/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb=. -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 -o /tmp/scan-build-2020-09-26-161721-17566-1 -x c++ /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp
1//===-- SemaCoroutine.cpp - Semantic Analysis for Coroutines --------------===//
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 semantic analysis for C++ Coroutines.
10//
11// This file contains references to sections of the Coroutines TS, which
12// can be found at http://wg21.link/coroutines.
13//
14//===----------------------------------------------------------------------===//
15
16#include "CoroutineStmtBuilder.h"
17#include "clang/AST/ASTLambda.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/AST/StmtCXX.h"
21#include "clang/Basic/Builtins.h"
22#include "clang/Lex/Preprocessor.h"
23#include "clang/Sema/Initialization.h"
24#include "clang/Sema/Overload.h"
25#include "clang/Sema/ScopeInfo.h"
26#include "clang/Sema/SemaInternal.h"
27#include "llvm/ADT/SmallSet.h"
28
29using namespace clang;
30using namespace sema;
31
32static LookupResult lookupMember(Sema &S, const char *Name, CXXRecordDecl *RD,
33 SourceLocation Loc, bool &Res) {
34 DeclarationName DN = S.PP.getIdentifierInfo(Name);
35 LookupResult LR(S, DN, Loc, Sema::LookupMemberName);
36 // Suppress diagnostics when a private member is selected. The same warnings
37 // will be produced again when building the call.
38 LR.suppressDiagnostics();
39 Res = S.LookupQualifiedName(LR, RD);
40 return LR;
41}
42
43static bool lookupMember(Sema &S, const char *Name, CXXRecordDecl *RD,
44 SourceLocation Loc) {
45 bool Res;
46 lookupMember(S, Name, RD, Loc, Res);
47 return Res;
48}
49
50/// Look up the std::coroutine_traits<...>::promise_type for the given
51/// function type.
52static QualType lookupPromiseType(Sema &S, const FunctionDecl *FD,
53 SourceLocation KwLoc) {
54 const FunctionProtoType *FnType = FD->getType()->castAs<FunctionProtoType>();
55 const SourceLocation FuncLoc = FD->getLocation();
56 // FIXME: Cache std::coroutine_traits once we've found it.
57 NamespaceDecl *StdExp = S.lookupStdExperimentalNamespace();
58 if (!StdExp) {
59 S.Diag(KwLoc, diag::err_implied_coroutine_type_not_found)
60 << "std::experimental::coroutine_traits";
61 return QualType();
62 }
63
64 ClassTemplateDecl *CoroTraits = S.lookupCoroutineTraits(KwLoc, FuncLoc);
65 if (!CoroTraits) {
66 return QualType();
67 }
68
69 // Form template argument list for coroutine_traits<R, P1, P2, ...> according
70 // to [dcl.fct.def.coroutine]3
71 TemplateArgumentListInfo Args(KwLoc, KwLoc);
72 auto AddArg = [&](QualType T) {
73 Args.addArgument(TemplateArgumentLoc(
74 TemplateArgument(T), S.Context.getTrivialTypeSourceInfo(T, KwLoc)));
75 };
76 AddArg(FnType->getReturnType());
77 // If the function is a non-static member function, add the type
78 // of the implicit object parameter before the formal parameters.
79 if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
80 if (MD->isInstance()) {
81 // [over.match.funcs]4
82 // For non-static member functions, the type of the implicit object
83 // parameter is
84 // -- "lvalue reference to cv X" for functions declared without a
85 // ref-qualifier or with the & ref-qualifier
86 // -- "rvalue reference to cv X" for functions declared with the &&
87 // ref-qualifier
88 QualType T = MD->getThisType()->castAs<PointerType>()->getPointeeType();
89 T = FnType->getRefQualifier() == RQ_RValue
90 ? S.Context.getRValueReferenceType(T)
91 : S.Context.getLValueReferenceType(T, /*SpelledAsLValue*/ true);
92 AddArg(T);
93 }
94 }
95 for (QualType T : FnType->getParamTypes())
96 AddArg(T);
97
98 // Build the template-id.
99 QualType CoroTrait =
100 S.CheckTemplateIdType(TemplateName(CoroTraits), KwLoc, Args);
101 if (CoroTrait.isNull())
102 return QualType();
103 if (S.RequireCompleteType(KwLoc, CoroTrait,
104 diag::err_coroutine_type_missing_specialization))
105 return QualType();
106
107 auto *RD = CoroTrait->getAsCXXRecordDecl();
108 assert(RD && "specialization of class template is not a class?")((RD && "specialization of class template is not a class?"
) ? static_cast<void> (0) : __assert_fail ("RD && \"specialization of class template is not a class?\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 108, __PRETTY_FUNCTION__))
;
109
110 // Look up the ::promise_type member.
111 LookupResult R(S, &S.PP.getIdentifierTable().get("promise_type"), KwLoc,
112 Sema::LookupOrdinaryName);
113 S.LookupQualifiedName(R, RD);
114 auto *Promise = R.getAsSingle<TypeDecl>();
115 if (!Promise) {
116 S.Diag(FuncLoc,
117 diag::err_implied_std_coroutine_traits_promise_type_not_found)
118 << RD;
119 return QualType();
120 }
121 // The promise type is required to be a class type.
122 QualType PromiseType = S.Context.getTypeDeclType(Promise);
123
124 auto buildElaboratedType = [&]() {
125 auto *NNS = NestedNameSpecifier::Create(S.Context, nullptr, StdExp);
126 NNS = NestedNameSpecifier::Create(S.Context, NNS, false,
127 CoroTrait.getTypePtr());
128 return S.Context.getElaboratedType(ETK_None, NNS, PromiseType);
129 };
130
131 if (!PromiseType->getAsCXXRecordDecl()) {
132 S.Diag(FuncLoc,
133 diag::err_implied_std_coroutine_traits_promise_type_not_class)
134 << buildElaboratedType();
135 return QualType();
136 }
137 if (S.RequireCompleteType(FuncLoc, buildElaboratedType(),
138 diag::err_coroutine_promise_type_incomplete))
139 return QualType();
140
141 return PromiseType;
142}
143
144/// Look up the std::experimental::coroutine_handle<PromiseType>.
145static QualType lookupCoroutineHandleType(Sema &S, QualType PromiseType,
146 SourceLocation Loc) {
147 if (PromiseType.isNull())
148 return QualType();
149
150 NamespaceDecl *StdExp = S.lookupStdExperimentalNamespace();
151 assert(StdExp && "Should already be diagnosed")((StdExp && "Should already be diagnosed") ? static_cast
<void> (0) : __assert_fail ("StdExp && \"Should already be diagnosed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 151, __PRETTY_FUNCTION__))
;
152
153 LookupResult Result(S, &S.PP.getIdentifierTable().get("coroutine_handle"),
154 Loc, Sema::LookupOrdinaryName);
155 if (!S.LookupQualifiedName(Result, StdExp)) {
156 S.Diag(Loc, diag::err_implied_coroutine_type_not_found)
157 << "std::experimental::coroutine_handle";
158 return QualType();
159 }
160
161 ClassTemplateDecl *CoroHandle = Result.getAsSingle<ClassTemplateDecl>();
162 if (!CoroHandle) {
163 Result.suppressDiagnostics();
164 // We found something weird. Complain about the first thing we found.
165 NamedDecl *Found = *Result.begin();
166 S.Diag(Found->getLocation(), diag::err_malformed_std_coroutine_handle);
167 return QualType();
168 }
169
170 // Form template argument list for coroutine_handle<Promise>.
171 TemplateArgumentListInfo Args(Loc, Loc);
172 Args.addArgument(TemplateArgumentLoc(
173 TemplateArgument(PromiseType),
174 S.Context.getTrivialTypeSourceInfo(PromiseType, Loc)));
175
176 // Build the template-id.
177 QualType CoroHandleType =
178 S.CheckTemplateIdType(TemplateName(CoroHandle), Loc, Args);
179 if (CoroHandleType.isNull())
180 return QualType();
181 if (S.RequireCompleteType(Loc, CoroHandleType,
182 diag::err_coroutine_type_missing_specialization))
183 return QualType();
184
185 return CoroHandleType;
186}
187
188static bool isValidCoroutineContext(Sema &S, SourceLocation Loc,
189 StringRef Keyword) {
190 // [expr.await]p2 dictates that 'co_await' and 'co_yield' must be used within
191 // a function body.
192 // FIXME: This also covers [expr.await]p2: "An await-expression shall not
193 // appear in a default argument." But the diagnostic QoI here could be
194 // improved to inform the user that default arguments specifically are not
195 // allowed.
196 auto *FD = dyn_cast<FunctionDecl>(S.CurContext);
197 if (!FD) {
198 S.Diag(Loc, isa<ObjCMethodDecl>(S.CurContext)
199 ? diag::err_coroutine_objc_method
200 : diag::err_coroutine_outside_function) << Keyword;
201 return false;
202 }
203
204 // An enumeration for mapping the diagnostic type to the correct diagnostic
205 // selection index.
206 enum InvalidFuncDiag {
207 DiagCtor = 0,
208 DiagDtor,
209 DiagMain,
210 DiagConstexpr,
211 DiagAutoRet,
212 DiagVarargs,
213 DiagConsteval,
214 };
215 bool Diagnosed = false;
216 auto DiagInvalid = [&](InvalidFuncDiag ID) {
217 S.Diag(Loc, diag::err_coroutine_invalid_func_context) << ID << Keyword;
218 Diagnosed = true;
219 return false;
220 };
221
222 // Diagnose when a constructor, destructor
223 // or the function 'main' are declared as a coroutine.
224 auto *MD = dyn_cast<CXXMethodDecl>(FD);
225 // [class.ctor]p11: "A constructor shall not be a coroutine."
226 if (MD && isa<CXXConstructorDecl>(MD))
227 return DiagInvalid(DiagCtor);
228 // [class.dtor]p17: "A destructor shall not be a coroutine."
229 else if (MD && isa<CXXDestructorDecl>(MD))
230 return DiagInvalid(DiagDtor);
231 // [basic.start.main]p3: "The function main shall not be a coroutine."
232 else if (FD->isMain())
233 return DiagInvalid(DiagMain);
234
235 // Emit a diagnostics for each of the following conditions which is not met.
236 // [expr.const]p2: "An expression e is a core constant expression unless the
237 // evaluation of e [...] would evaluate one of the following expressions:
238 // [...] an await-expression [...] a yield-expression."
239 if (FD->isConstexpr())
240 DiagInvalid(FD->isConsteval() ? DiagConsteval : DiagConstexpr);
241 // [dcl.spec.auto]p15: "A function declared with a return type that uses a
242 // placeholder type shall not be a coroutine."
243 if (FD->getReturnType()->isUndeducedType())
244 DiagInvalid(DiagAutoRet);
245 // [dcl.fct.def.coroutine]p1: "The parameter-declaration-clause of the
246 // coroutine shall not terminate with an ellipsis that is not part of a
247 // parameter-declaration."
248 if (FD->isVariadic())
249 DiagInvalid(DiagVarargs);
250
251 return !Diagnosed;
252}
253
254static ExprResult buildOperatorCoawaitLookupExpr(Sema &SemaRef, Scope *S,
255 SourceLocation Loc) {
256 DeclarationName OpName =
257 SemaRef.Context.DeclarationNames.getCXXOperatorName(OO_Coawait);
258 LookupResult Operators(SemaRef, OpName, SourceLocation(),
259 Sema::LookupOperatorName);
260 SemaRef.LookupName(Operators, S);
261
262 assert(!Operators.isAmbiguous() && "Operator lookup cannot be ambiguous")((!Operators.isAmbiguous() && "Operator lookup cannot be ambiguous"
) ? static_cast<void> (0) : __assert_fail ("!Operators.isAmbiguous() && \"Operator lookup cannot be ambiguous\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 262, __PRETTY_FUNCTION__))
;
263 const auto &Functions = Operators.asUnresolvedSet();
264 bool IsOverloaded =
265 Functions.size() > 1 ||
266 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin()));
267 Expr *CoawaitOp = UnresolvedLookupExpr::Create(
268 SemaRef.Context, /*NamingClass*/ nullptr, NestedNameSpecifierLoc(),
269 DeclarationNameInfo(OpName, Loc), /*RequiresADL*/ true, IsOverloaded,
270 Functions.begin(), Functions.end());
271 assert(CoawaitOp)((CoawaitOp) ? static_cast<void> (0) : __assert_fail ("CoawaitOp"
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 271, __PRETTY_FUNCTION__))
;
272 return CoawaitOp;
273}
274
275/// Build a call to 'operator co_await' if there is a suitable operator for
276/// the given expression.
277static ExprResult buildOperatorCoawaitCall(Sema &SemaRef, SourceLocation Loc,
278 Expr *E,
279 UnresolvedLookupExpr *Lookup) {
280 UnresolvedSet<16> Functions;
281 Functions.append(Lookup->decls_begin(), Lookup->decls_end());
282 return SemaRef.CreateOverloadedUnaryOp(Loc, UO_Coawait, Functions, E);
283}
284
285static ExprResult buildOperatorCoawaitCall(Sema &SemaRef, Scope *S,
286 SourceLocation Loc, Expr *E) {
287 ExprResult R = buildOperatorCoawaitLookupExpr(SemaRef, S, Loc);
288 if (R.isInvalid())
289 return ExprError();
290 return buildOperatorCoawaitCall(SemaRef, Loc, E,
291 cast<UnresolvedLookupExpr>(R.get()));
292}
293
294static Expr *buildBuiltinCall(Sema &S, SourceLocation Loc, Builtin::ID Id,
295 MultiExprArg CallArgs) {
296 StringRef Name = S.Context.BuiltinInfo.getName(Id);
297 LookupResult R(S, &S.Context.Idents.get(Name), Loc, Sema::LookupOrdinaryName);
298 S.LookupName(R, S.TUScope, /*AllowBuiltinCreation=*/true);
299
300 auto *BuiltInDecl = R.getAsSingle<FunctionDecl>();
301 assert(BuiltInDecl && "failed to find builtin declaration")((BuiltInDecl && "failed to find builtin declaration"
) ? static_cast<void> (0) : __assert_fail ("BuiltInDecl && \"failed to find builtin declaration\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 301, __PRETTY_FUNCTION__))
;
302
303 ExprResult DeclRef =
304 S.BuildDeclRefExpr(BuiltInDecl, BuiltInDecl->getType(), VK_LValue, Loc);
305 assert(DeclRef.isUsable() && "Builtin reference cannot fail")((DeclRef.isUsable() && "Builtin reference cannot fail"
) ? static_cast<void> (0) : __assert_fail ("DeclRef.isUsable() && \"Builtin reference cannot fail\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 305, __PRETTY_FUNCTION__))
;
306
307 ExprResult Call =
308 S.BuildCallExpr(/*Scope=*/nullptr, DeclRef.get(), Loc, CallArgs, Loc);
309
310 assert(!Call.isInvalid() && "Call to builtin cannot fail!")((!Call.isInvalid() && "Call to builtin cannot fail!"
) ? static_cast<void> (0) : __assert_fail ("!Call.isInvalid() && \"Call to builtin cannot fail!\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 310, __PRETTY_FUNCTION__))
;
311 return Call.get();
312}
313
314static ExprResult buildCoroutineHandle(Sema &S, QualType PromiseType,
315 SourceLocation Loc) {
316 QualType CoroHandleType = lookupCoroutineHandleType(S, PromiseType, Loc);
317 if (CoroHandleType.isNull())
318 return ExprError();
319
320 DeclContext *LookupCtx = S.computeDeclContext(CoroHandleType);
321 LookupResult Found(S, &S.PP.getIdentifierTable().get("from_address"), Loc,
322 Sema::LookupOrdinaryName);
323 if (!S.LookupQualifiedName(Found, LookupCtx)) {
324 S.Diag(Loc, diag::err_coroutine_handle_missing_member)
325 << "from_address";
326 return ExprError();
327 }
328
329 Expr *FramePtr =
330 buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_frame, {});
331
332 CXXScopeSpec SS;
333 ExprResult FromAddr =
334 S.BuildDeclarationNameExpr(SS, Found, /*NeedsADL=*/false);
335 if (FromAddr.isInvalid())
336 return ExprError();
337
338 return S.BuildCallExpr(nullptr, FromAddr.get(), Loc, FramePtr, Loc);
339}
340
341struct ReadySuspendResumeResult {
342 enum AwaitCallType { ACT_Ready, ACT_Suspend, ACT_Resume };
343 Expr *Results[3];
344 OpaqueValueExpr *OpaqueValue;
345 bool IsInvalid;
346};
347
348static ExprResult buildMemberCall(Sema &S, Expr *Base, SourceLocation Loc,
349 StringRef Name, MultiExprArg Args) {
350 DeclarationNameInfo NameInfo(&S.PP.getIdentifierTable().get(Name), Loc);
351
352 // FIXME: Fix BuildMemberReferenceExpr to take a const CXXScopeSpec&.
353 CXXScopeSpec SS;
354 ExprResult Result = S.BuildMemberReferenceExpr(
355 Base, Base->getType(), Loc, /*IsPtr=*/false, SS,
356 SourceLocation(), nullptr, NameInfo, /*TemplateArgs=*/nullptr,
357 /*Scope=*/nullptr);
358 if (Result.isInvalid())
359 return ExprError();
360
361 // We meant exactly what we asked for. No need for typo correction.
362 if (auto *TE = dyn_cast<TypoExpr>(Result.get())) {
363 S.clearDelayedTypo(TE);
364 S.Diag(Loc, diag::err_no_member)
365 << NameInfo.getName() << Base->getType()->getAsCXXRecordDecl()
366 << Base->getSourceRange();
367 return ExprError();
368 }
369
370 return S.BuildCallExpr(nullptr, Result.get(), Loc, Args, Loc, nullptr);
371}
372
373// See if return type is coroutine-handle and if so, invoke builtin coro-resume
374// on its address. This is to enable experimental support for coroutine-handle
375// returning await_suspend that results in a guaranteed tail call to the target
376// coroutine.
377static Expr *maybeTailCall(Sema &S, QualType RetType, Expr *E,
378 SourceLocation Loc) {
379 if (RetType->isReferenceType())
380 return nullptr;
381 Type const *T = RetType.getTypePtr();
382 if (!T->isClassType() && !T->isStructureType())
383 return nullptr;
384
385 // FIXME: Add convertability check to coroutine_handle<>. Possibly via
386 // EvaluateBinaryTypeTrait(BTT_IsConvertible, ...) which is at the moment
387 // a private function in SemaExprCXX.cpp
388
389 ExprResult AddressExpr = buildMemberCall(S, E, Loc, "address", None);
390 if (AddressExpr.isInvalid())
391 return nullptr;
392
393 Expr *JustAddress = AddressExpr.get();
394
395 // Check that the type of AddressExpr is void*
396 if (!JustAddress->getType().getTypePtr()->isVoidPointerType())
397 S.Diag(cast<CallExpr>(JustAddress)->getCalleeDecl()->getLocation(),
398 diag::warn_coroutine_handle_address_invalid_return_type)
399 << JustAddress->getType();
400
401 // The coroutine handle used to obtain the address is no longer needed
402 // at this point, clean it up to avoid unnecessarily long lifetime which
403 // could lead to unnecessary spilling.
404 JustAddress = S.MaybeCreateExprWithCleanups(JustAddress);
405 return buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_resume,
406 JustAddress);
407}
408
409/// Build calls to await_ready, await_suspend, and await_resume for a co_await
410/// expression.
411static ReadySuspendResumeResult buildCoawaitCalls(Sema &S, VarDecl *CoroPromise,
412 SourceLocation Loc, Expr *E) {
413 OpaqueValueExpr *Operand = new (S.Context)
414 OpaqueValueExpr(Loc, E->getType(), VK_LValue, E->getObjectKind(), E);
415
416 // Assume invalid until we see otherwise.
417 ReadySuspendResumeResult Calls = {{}, Operand, /*IsInvalid=*/true};
418
419 ExprResult CoroHandleRes = buildCoroutineHandle(S, CoroPromise->getType(), Loc);
420 if (CoroHandleRes.isInvalid())
421 return Calls;
422 Expr *CoroHandle = CoroHandleRes.get();
423
424 const StringRef Funcs[] = {"await_ready", "await_suspend", "await_resume"};
425 MultiExprArg Args[] = {None, CoroHandle, None};
426 for (size_t I = 0, N = llvm::array_lengthof(Funcs); I != N; ++I) {
427 ExprResult Result = buildMemberCall(S, Operand, Loc, Funcs[I], Args[I]);
428 if (Result.isInvalid())
429 return Calls;
430 Calls.Results[I] = Result.get();
431 }
432
433 // Assume the calls are valid; all further checking should make them invalid.
434 Calls.IsInvalid = false;
435
436 using ACT = ReadySuspendResumeResult::AwaitCallType;
437 CallExpr *AwaitReady = cast<CallExpr>(Calls.Results[ACT::ACT_Ready]);
438 if (!AwaitReady->getType()->isDependentType()) {
439 // [expr.await]p3 [...]
440 // — await-ready is the expression e.await_ready(), contextually converted
441 // to bool.
442 ExprResult Conv = S.PerformContextuallyConvertToBool(AwaitReady);
443 if (Conv.isInvalid()) {
444 S.Diag(AwaitReady->getDirectCallee()->getBeginLoc(),
445 diag::note_await_ready_no_bool_conversion);
446 S.Diag(Loc, diag::note_coroutine_promise_call_implicitly_required)
447 << AwaitReady->getDirectCallee() << E->getSourceRange();
448 Calls.IsInvalid = true;
449 }
450 Calls.Results[ACT::ACT_Ready] = Conv.get();
451 }
452 CallExpr *AwaitSuspend = cast<CallExpr>(Calls.Results[ACT::ACT_Suspend]);
453 if (!AwaitSuspend->getType()->isDependentType()) {
454 // [expr.await]p3 [...]
455 // - await-suspend is the expression e.await_suspend(h), which shall be
456 // a prvalue of type void, bool, or std::coroutine_handle<Z> for some
457 // type Z.
458 QualType RetType = AwaitSuspend->getCallReturnType(S.Context);
459
460 // Experimental support for coroutine_handle returning await_suspend.
461 if (Expr *TailCallSuspend = maybeTailCall(S, RetType, AwaitSuspend, Loc))
462 Calls.Results[ACT::ACT_Suspend] = TailCallSuspend;
463 else {
464 // non-class prvalues always have cv-unqualified types
465 if (RetType->isReferenceType() ||
466 (!RetType->isBooleanType() && !RetType->isVoidType())) {
467 S.Diag(AwaitSuspend->getCalleeDecl()->getLocation(),
468 diag::err_await_suspend_invalid_return_type)
469 << RetType;
470 S.Diag(Loc, diag::note_coroutine_promise_call_implicitly_required)
471 << AwaitSuspend->getDirectCallee();
472 Calls.IsInvalid = true;
473 }
474 }
475 }
476
477 return Calls;
478}
479
480static ExprResult buildPromiseCall(Sema &S, VarDecl *Promise,
481 SourceLocation Loc, StringRef Name,
482 MultiExprArg Args) {
483
484 // Form a reference to the promise.
485 ExprResult PromiseRef = S.BuildDeclRefExpr(
486 Promise, Promise->getType().getNonReferenceType(), VK_LValue, Loc);
487 if (PromiseRef.isInvalid())
488 return ExprError();
489
490 return buildMemberCall(S, PromiseRef.get(), Loc, Name, Args);
491}
492
493VarDecl *Sema::buildCoroutinePromise(SourceLocation Loc) {
494 assert(isa<FunctionDecl>(CurContext) && "not in a function scope")((isa<FunctionDecl>(CurContext) && "not in a function scope"
) ? static_cast<void> (0) : __assert_fail ("isa<FunctionDecl>(CurContext) && \"not in a function scope\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 494, __PRETTY_FUNCTION__))
;
495 auto *FD = cast<FunctionDecl>(CurContext);
496 bool IsThisDependentType = [&] {
497 if (auto *MD = dyn_cast_or_null<CXXMethodDecl>(FD))
498 return MD->isInstance() && MD->getThisType()->isDependentType();
499 else
500 return false;
501 }();
502
503 QualType T = FD->getType()->isDependentType() || IsThisDependentType
504 ? Context.DependentTy
505 : lookupPromiseType(*this, FD, Loc);
506 if (T.isNull())
507 return nullptr;
508
509 auto *VD = VarDecl::Create(Context, FD, FD->getLocation(), FD->getLocation(),
510 &PP.getIdentifierTable().get("__promise"), T,
511 Context.getTrivialTypeSourceInfo(T, Loc), SC_None);
512 CheckVariableDeclarationType(VD);
513 if (VD->isInvalidDecl())
514 return nullptr;
515
516 auto *ScopeInfo = getCurFunction();
517
518 // Build a list of arguments, based on the coroutine function's arguments,
519 // that if present will be passed to the promise type's constructor.
520 llvm::SmallVector<Expr *, 4> CtorArgExprs;
521
522 // Add implicit object parameter.
523 if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
524 if (MD->isInstance() && !isLambdaCallOperator(MD)) {
525 ExprResult ThisExpr = ActOnCXXThis(Loc);
526 if (ThisExpr.isInvalid())
527 return nullptr;
528 ThisExpr = CreateBuiltinUnaryOp(Loc, UO_Deref, ThisExpr.get());
529 if (ThisExpr.isInvalid())
530 return nullptr;
531 CtorArgExprs.push_back(ThisExpr.get());
532 }
533 }
534
535 // Add the coroutine function's parameters.
536 auto &Moves = ScopeInfo->CoroutineParameterMoves;
537 for (auto *PD : FD->parameters()) {
538 if (PD->getType()->isDependentType())
539 continue;
540
541 auto RefExpr = ExprEmpty();
542 auto Move = Moves.find(PD);
543 assert(Move != Moves.end() &&((Move != Moves.end() && "Coroutine function parameter not inserted into move map"
) ? static_cast<void> (0) : __assert_fail ("Move != Moves.end() && \"Coroutine function parameter not inserted into move map\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 544, __PRETTY_FUNCTION__))
544 "Coroutine function parameter not inserted into move map")((Move != Moves.end() && "Coroutine function parameter not inserted into move map"
) ? static_cast<void> (0) : __assert_fail ("Move != Moves.end() && \"Coroutine function parameter not inserted into move map\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 544, __PRETTY_FUNCTION__))
;
545 // If a reference to the function parameter exists in the coroutine
546 // frame, use that reference.
547 auto *MoveDecl =
548 cast<VarDecl>(cast<DeclStmt>(Move->second)->getSingleDecl());
549 RefExpr =
550 BuildDeclRefExpr(MoveDecl, MoveDecl->getType().getNonReferenceType(),
551 ExprValueKind::VK_LValue, FD->getLocation());
552 if (RefExpr.isInvalid())
553 return nullptr;
554 CtorArgExprs.push_back(RefExpr.get());
555 }
556
557 // If we have a non-zero number of constructor arguments, try to use them.
558 // Otherwise, fall back to the promise type's default constructor.
559 if (!CtorArgExprs.empty()) {
560 // Create an initialization sequence for the promise type using the
561 // constructor arguments, wrapped in a parenthesized list expression.
562 Expr *PLE = ParenListExpr::Create(Context, FD->getLocation(),
563 CtorArgExprs, FD->getLocation());
564 InitializedEntity Entity = InitializedEntity::InitializeVariable(VD);
565 InitializationKind Kind = InitializationKind::CreateForInit(
566 VD->getLocation(), /*DirectInit=*/true, PLE);
567 InitializationSequence InitSeq(*this, Entity, Kind, CtorArgExprs,
568 /*TopLevelOfInitList=*/false,
569 /*TreatUnavailableAsInvalid=*/false);
570
571 // Attempt to initialize the promise type with the arguments.
572 // If that fails, fall back to the promise type's default constructor.
573 if (InitSeq) {
574 ExprResult Result = InitSeq.Perform(*this, Entity, Kind, CtorArgExprs);
575 if (Result.isInvalid()) {
576 VD->setInvalidDecl();
577 } else if (Result.get()) {
578 VD->setInit(MaybeCreateExprWithCleanups(Result.get()));
579 VD->setInitStyle(VarDecl::CallInit);
580 CheckCompleteVariableDeclaration(VD);
581 }
582 } else
583 ActOnUninitializedDecl(VD);
584 } else
585 ActOnUninitializedDecl(VD);
586
587 FD->addDecl(VD);
588 return VD;
589}
590
591/// Check that this is a context in which a coroutine suspension can appear.
592static FunctionScopeInfo *checkCoroutineContext(Sema &S, SourceLocation Loc,
593 StringRef Keyword,
594 bool IsImplicit = false) {
595 if (!isValidCoroutineContext(S, Loc, Keyword))
596 return nullptr;
597
598 assert(isa<FunctionDecl>(S.CurContext) && "not in a function scope")((isa<FunctionDecl>(S.CurContext) && "not in a function scope"
) ? static_cast<void> (0) : __assert_fail ("isa<FunctionDecl>(S.CurContext) && \"not in a function scope\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 598, __PRETTY_FUNCTION__))
;
599
600 auto *ScopeInfo = S.getCurFunction();
601 assert(ScopeInfo && "missing function scope for function")((ScopeInfo && "missing function scope for function")
? static_cast<void> (0) : __assert_fail ("ScopeInfo && \"missing function scope for function\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 601, __PRETTY_FUNCTION__))
;
602
603 if (ScopeInfo->FirstCoroutineStmtLoc.isInvalid() && !IsImplicit)
604 ScopeInfo->setFirstCoroutineStmt(Loc, Keyword);
605
606 if (ScopeInfo->CoroutinePromise)
607 return ScopeInfo;
608
609 if (!S.buildCoroutineParameterMoves(Loc))
610 return nullptr;
611
612 ScopeInfo->CoroutinePromise = S.buildCoroutinePromise(Loc);
613 if (!ScopeInfo->CoroutinePromise)
614 return nullptr;
615
616 return ScopeInfo;
617}
618
619/// Recursively check \p E and all its children to see if any call target
620/// (including constructor call) is declared noexcept. Also any value returned
621/// from the call has a noexcept destructor.
622static void checkNoThrow(Sema &S, const Stmt *E,
623 llvm::SmallPtrSetImpl<const Decl *> &ThrowingDecls) {
624 auto checkDeclNoexcept = [&](const Decl *D, bool IsDtor = false) {
625 // In the case of dtor, the call to dtor is implicit and hence we should
626 // pass nullptr to canCalleeThrow.
627 if (Sema::canCalleeThrow(S, IsDtor ? nullptr : cast<Expr>(E), D)) {
628 if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
629 // co_await promise.final_suspend() could end up calling
630 // __builtin_coro_resume for symmetric transfer if await_suspend()
631 // returns a handle. In that case, even __builtin_coro_resume is not
632 // declared as noexcept and may throw, it does not throw _into_ the
633 // coroutine that just suspended, but rather throws back out from
634 // whoever called coroutine_handle::resume(), hence we claim that
635 // logically it does not throw.
636 if (FD->getBuiltinID() == Builtin::BI__builtin_coro_resume)
637 return;
638 }
639 if (ThrowingDecls.empty()) {
640 // First time seeing an error, emit the error message.
641 S.Diag(cast<FunctionDecl>(S.CurContext)->getLocation(),
642 diag::err_coroutine_promise_final_suspend_requires_nothrow);
643 }
644 ThrowingDecls.insert(D);
645 }
646 };
647 auto SC = E->getStmtClass();
648 if (SC == Expr::CXXConstructExprClass) {
13
Assuming 'SC' is not equal to CXXConstructExprClass
14
Taking false branch
22
Assuming 'SC' is not equal to CXXConstructExprClass
23
Taking false branch
649 auto const *Ctor = cast<CXXConstructExpr>(E)->getConstructor();
650 checkDeclNoexcept(Ctor);
651 // Check the corresponding destructor of the constructor.
652 checkDeclNoexcept(Ctor->getParent()->getDestructor(), true);
653 } else if (SC == Expr::CallExprClass || SC == Expr::CXXMemberCallExprClass ||
15
Assuming 'SC' is not equal to CallExprClass
16
Assuming 'SC' is not equal to CXXMemberCallExprClass
18
Taking false branch
24
Assuming 'SC' is equal to CallExprClass
654 SC == Expr::CXXOperatorCallExprClass) {
17
Assuming 'SC' is not equal to CXXOperatorCallExprClass
655 if (!cast<CallExpr>(E)->isTypeDependent()) {
25
'E' is a 'CallExpr'
26
Assuming the condition is true
27
Taking true branch
656 checkDeclNoexcept(cast<CallExpr>(E)->getCalleeDecl());
28
'E' is a 'CallExpr'
657 auto ReturnType = cast<CallExpr>(E)->getCallReturnType(S.getASTContext());
29
'E' is a 'CallExpr'
658 // Check the destructor of the call return type, if any.
659 if (ReturnType.isDestructedType() ==
30
Assuming the condition is true
31
Taking true branch
660 QualType::DestructionKind::DK_cxx_destructor) {
661 const auto *T =
662 cast<RecordType>(ReturnType.getCanonicalType().getTypePtr());
32
The object is a 'RecordType'
663 checkDeclNoexcept(
664 dyn_cast<CXXRecordDecl>(T->getDecl())->getDestructor(), true);
33
Assuming the object is not a 'CXXRecordDecl'
34
Called C++ object pointer is null
665 }
666 }
667 }
668 for (const auto *Child : E->children()) {
669 if (!Child)
19
Assuming 'Child' is non-null
20
Taking false branch
670 continue;
671 checkNoThrow(S, Child, ThrowingDecls);
21
Calling 'checkNoThrow'
672 }
673}
674
675bool Sema::checkFinalSuspendNoThrow(const Stmt *FinalSuspend) {
676 llvm::SmallPtrSet<const Decl *, 4> ThrowingDecls;
677 // We first collect all declarations that should not throw but not declared
678 // with noexcept. We then sort them based on the location before printing.
679 // This is to avoid emitting the same note multiple times on the same
680 // declaration, and also provide a deterministic order for the messages.
681 checkNoThrow(*this, FinalSuspend, ThrowingDecls);
12
Calling 'checkNoThrow'
682 auto SortedDecls = llvm::SmallVector<const Decl *, 4>{ThrowingDecls.begin(),
683 ThrowingDecls.end()};
684 sort(SortedDecls, [](const Decl *A, const Decl *B) {
685 return A->getEndLoc() < B->getEndLoc();
686 });
687 for (const auto *D : SortedDecls) {
688 Diag(D->getEndLoc(), diag::note_coroutine_function_declare_noexcept);
689 }
690 return ThrowingDecls.empty();
691}
692
693bool Sema::ActOnCoroutineBodyStart(Scope *SC, SourceLocation KWLoc,
694 StringRef Keyword) {
695 if (!checkCoroutineContext(*this, KWLoc, Keyword))
2
Taking false branch
696 return false;
697 auto *ScopeInfo = getCurFunction();
698 assert(ScopeInfo->CoroutinePromise)((ScopeInfo->CoroutinePromise) ? static_cast<void> (
0) : __assert_fail ("ScopeInfo->CoroutinePromise", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 698, __PRETTY_FUNCTION__))
;
3
Assuming field 'CoroutinePromise' is non-null
4
'?' condition is true
699
700 // If we have existing coroutine statements then we have already built
701 // the initial and final suspend points.
702 if (!ScopeInfo->NeedsCoroutineSuspends)
5
Assuming field 'NeedsCoroutineSuspends' is true
6
Taking false branch
703 return true;
704
705 ScopeInfo->setNeedsCoroutineSuspends(false);
706
707 auto *Fn = cast<FunctionDecl>(CurContext);
7
Field 'CurContext' is a 'FunctionDecl'
708 SourceLocation Loc = Fn->getLocation();
709 // Build the initial suspend point
710 auto buildSuspends = [&](StringRef Name) mutable -> StmtResult {
711 ExprResult Suspend =
712 buildPromiseCall(*this, ScopeInfo->CoroutinePromise, Loc, Name, None);
713 if (Suspend.isInvalid())
714 return StmtError();
715 Suspend = buildOperatorCoawaitCall(*this, SC, Loc, Suspend.get());
716 if (Suspend.isInvalid())
717 return StmtError();
718 Suspend = BuildResolvedCoawaitExpr(Loc, Suspend.get(),
719 /*IsImplicit*/ true);
720 Suspend = ActOnFinishFullExpr(Suspend.get(), /*DiscardedValue*/ false);
721 if (Suspend.isInvalid()) {
722 Diag(Loc, diag::note_coroutine_promise_suspend_implicitly_required)
723 << ((Name == "initial_suspend") ? 0 : 1);
724 Diag(KWLoc, diag::note_declared_coroutine_here) << Keyword;
725 return StmtError();
726 }
727 return cast<Stmt>(Suspend.get());
728 };
729
730 StmtResult InitSuspend = buildSuspends("initial_suspend");
731 if (InitSuspend.isInvalid())
8
Assuming the condition is false
9
Taking false branch
732 return true;
733
734 StmtResult FinalSuspend = buildSuspends("final_suspend");
735 if (FinalSuspend.isInvalid() || !checkFinalSuspendNoThrow(FinalSuspend.get()))
10
Assuming the condition is false
11
Calling 'Sema::checkFinalSuspendNoThrow'
736 return true;
737
738 ScopeInfo->setCoroutineSuspends(InitSuspend.get(), FinalSuspend.get());
739
740 return true;
741}
742
743// Recursively walks up the scope hierarchy until either a 'catch' or a function
744// scope is found, whichever comes first.
745static bool isWithinCatchScope(Scope *S) {
746 // 'co_await' and 'co_yield' keywords are disallowed within catch blocks, but
747 // lambdas that use 'co_await' are allowed. The loop below ends when a
748 // function scope is found in order to ensure the following behavior:
749 //
750 // void foo() { // <- function scope
751 // try { //
752 // co_await x; // <- 'co_await' is OK within a function scope
753 // } catch { // <- catch scope
754 // co_await x; // <- 'co_await' is not OK within a catch scope
755 // []() { // <- function scope
756 // co_await x; // <- 'co_await' is OK within a function scope
757 // }();
758 // }
759 // }
760 while (S && !(S->getFlags() & Scope::FnScope)) {
761 if (S->getFlags() & Scope::CatchScope)
762 return true;
763 S = S->getParent();
764 }
765 return false;
766}
767
768// [expr.await]p2, emphasis added: "An await-expression shall appear only in
769// a *potentially evaluated* expression within the compound-statement of a
770// function-body *outside of a handler* [...] A context within a function
771// where an await-expression can appear is called a suspension context of the
772// function."
773static void checkSuspensionContext(Sema &S, SourceLocation Loc,
774 StringRef Keyword) {
775 // First emphasis of [expr.await]p2: must be a potentially evaluated context.
776 // That is, 'co_await' and 'co_yield' cannot appear in subexpressions of
777 // \c sizeof.
778 if (S.isUnevaluatedContext())
779 S.Diag(Loc, diag::err_coroutine_unevaluated_context) << Keyword;
780
781 // Second emphasis of [expr.await]p2: must be outside of an exception handler.
782 if (isWithinCatchScope(S.getCurScope()))
783 S.Diag(Loc, diag::err_coroutine_within_handler) << Keyword;
784}
785
786ExprResult Sema::ActOnCoawaitExpr(Scope *S, SourceLocation Loc, Expr *E) {
787 if (!ActOnCoroutineBodyStart(S, Loc, "co_await")) {
788 CorrectDelayedTyposInExpr(E);
789 return ExprError();
790 }
791
792 checkSuspensionContext(*this, Loc, "co_await");
793
794 if (E->getType()->isPlaceholderType()) {
795 ExprResult R = CheckPlaceholderExpr(E);
796 if (R.isInvalid()) return ExprError();
797 E = R.get();
798 }
799 ExprResult Lookup = buildOperatorCoawaitLookupExpr(*this, S, Loc);
800 if (Lookup.isInvalid())
801 return ExprError();
802 return BuildUnresolvedCoawaitExpr(Loc, E,
803 cast<UnresolvedLookupExpr>(Lookup.get()));
804}
805
806ExprResult Sema::BuildUnresolvedCoawaitExpr(SourceLocation Loc, Expr *E,
807 UnresolvedLookupExpr *Lookup) {
808 auto *FSI = checkCoroutineContext(*this, Loc, "co_await");
809 if (!FSI)
810 return ExprError();
811
812 if (E->getType()->isPlaceholderType()) {
813 ExprResult R = CheckPlaceholderExpr(E);
814 if (R.isInvalid())
815 return ExprError();
816 E = R.get();
817 }
818
819 auto *Promise = FSI->CoroutinePromise;
820 if (Promise->getType()->isDependentType()) {
821 Expr *Res =
822 new (Context) DependentCoawaitExpr(Loc, Context.DependentTy, E, Lookup);
823 return Res;
824 }
825
826 auto *RD = Promise->getType()->getAsCXXRecordDecl();
827 if (lookupMember(*this, "await_transform", RD, Loc)) {
828 ExprResult R = buildPromiseCall(*this, Promise, Loc, "await_transform", E);
829 if (R.isInvalid()) {
830 Diag(Loc,
831 diag::note_coroutine_promise_implicit_await_transform_required_here)
832 << E->getSourceRange();
833 return ExprError();
834 }
835 E = R.get();
836 }
837 ExprResult Awaitable = buildOperatorCoawaitCall(*this, Loc, E, Lookup);
838 if (Awaitable.isInvalid())
839 return ExprError();
840
841 return BuildResolvedCoawaitExpr(Loc, Awaitable.get());
842}
843
844ExprResult Sema::BuildResolvedCoawaitExpr(SourceLocation Loc, Expr *E,
845 bool IsImplicit) {
846 auto *Coroutine = checkCoroutineContext(*this, Loc, "co_await", IsImplicit);
847 if (!Coroutine)
848 return ExprError();
849
850 if (E->getType()->isPlaceholderType()) {
851 ExprResult R = CheckPlaceholderExpr(E);
852 if (R.isInvalid()) return ExprError();
853 E = R.get();
854 }
855
856 if (E->getType()->isDependentType()) {
857 Expr *Res = new (Context)
858 CoawaitExpr(Loc, Context.DependentTy, E, IsImplicit);
859 return Res;
860 }
861
862 // If the expression is a temporary, materialize it as an lvalue so that we
863 // can use it multiple times.
864 if (E->getValueKind() == VK_RValue)
865 E = CreateMaterializeTemporaryExpr(E->getType(), E, true);
866
867 // The location of the `co_await` token cannot be used when constructing
868 // the member call expressions since it's before the location of `Expr`, which
869 // is used as the start of the member call expression.
870 SourceLocation CallLoc = E->getExprLoc();
871
872 // Build the await_ready, await_suspend, await_resume calls.
873 ReadySuspendResumeResult RSS =
874 buildCoawaitCalls(*this, Coroutine->CoroutinePromise, CallLoc, E);
875 if (RSS.IsInvalid)
876 return ExprError();
877
878 Expr *Res =
879 new (Context) CoawaitExpr(Loc, E, RSS.Results[0], RSS.Results[1],
880 RSS.Results[2], RSS.OpaqueValue, IsImplicit);
881
882 return Res;
883}
884
885ExprResult Sema::ActOnCoyieldExpr(Scope *S, SourceLocation Loc, Expr *E) {
886 if (!ActOnCoroutineBodyStart(S, Loc, "co_yield")) {
887 CorrectDelayedTyposInExpr(E);
888 return ExprError();
889 }
890
891 checkSuspensionContext(*this, Loc, "co_yield");
892
893 // Build yield_value call.
894 ExprResult Awaitable = buildPromiseCall(
895 *this, getCurFunction()->CoroutinePromise, Loc, "yield_value", E);
896 if (Awaitable.isInvalid())
897 return ExprError();
898
899 // Build 'operator co_await' call.
900 Awaitable = buildOperatorCoawaitCall(*this, S, Loc, Awaitable.get());
901 if (Awaitable.isInvalid())
902 return ExprError();
903
904 return BuildCoyieldExpr(Loc, Awaitable.get());
905}
906ExprResult Sema::BuildCoyieldExpr(SourceLocation Loc, Expr *E) {
907 auto *Coroutine = checkCoroutineContext(*this, Loc, "co_yield");
908 if (!Coroutine)
909 return ExprError();
910
911 if (E->getType()->isPlaceholderType()) {
912 ExprResult R = CheckPlaceholderExpr(E);
913 if (R.isInvalid()) return ExprError();
914 E = R.get();
915 }
916
917 if (E->getType()->isDependentType()) {
918 Expr *Res = new (Context) CoyieldExpr(Loc, Context.DependentTy, E);
919 return Res;
920 }
921
922 // If the expression is a temporary, materialize it as an lvalue so that we
923 // can use it multiple times.
924 if (E->getValueKind() == VK_RValue)
925 E = CreateMaterializeTemporaryExpr(E->getType(), E, true);
926
927 // Build the await_ready, await_suspend, await_resume calls.
928 ReadySuspendResumeResult RSS =
929 buildCoawaitCalls(*this, Coroutine->CoroutinePromise, Loc, E);
930 if (RSS.IsInvalid)
931 return ExprError();
932
933 Expr *Res =
934 new (Context) CoyieldExpr(Loc, E, RSS.Results[0], RSS.Results[1],
935 RSS.Results[2], RSS.OpaqueValue);
936
937 return Res;
938}
939
940StmtResult Sema::ActOnCoreturnStmt(Scope *S, SourceLocation Loc, Expr *E) {
941 if (!ActOnCoroutineBodyStart(S, Loc, "co_return")) {
1
Calling 'Sema::ActOnCoroutineBodyStart'
942 CorrectDelayedTyposInExpr(E);
943 return StmtError();
944 }
945 return BuildCoreturnStmt(Loc, E);
946}
947
948StmtResult Sema::BuildCoreturnStmt(SourceLocation Loc, Expr *E,
949 bool IsImplicit) {
950 auto *FSI = checkCoroutineContext(*this, Loc, "co_return", IsImplicit);
951 if (!FSI)
952 return StmtError();
953
954 if (E && E->getType()->isPlaceholderType() &&
955 !E->getType()->isSpecificPlaceholderType(BuiltinType::Overload)) {
956 ExprResult R = CheckPlaceholderExpr(E);
957 if (R.isInvalid()) return StmtError();
958 E = R.get();
959 }
960
961 // Move the return value if we can
962 if (E) {
963 auto NRVOCandidate = this->getCopyElisionCandidate(E->getType(), E, CES_AsIfByStdMove);
964 if (NRVOCandidate) {
965 InitializedEntity Entity =
966 InitializedEntity::InitializeResult(Loc, E->getType(), NRVOCandidate);
967 ExprResult MoveResult = this->PerformMoveOrCopyInitialization(
968 Entity, NRVOCandidate, E->getType(), E);
969 if (MoveResult.get())
970 E = MoveResult.get();
971 }
972 }
973
974 // FIXME: If the operand is a reference to a variable that's about to go out
975 // of scope, we should treat the operand as an xvalue for this overload
976 // resolution.
977 VarDecl *Promise = FSI->CoroutinePromise;
978 ExprResult PC;
979 if (E && (isa<InitListExpr>(E) || !E->getType()->isVoidType())) {
980 PC = buildPromiseCall(*this, Promise, Loc, "return_value", E);
981 } else {
982 E = MakeFullDiscardedValueExpr(E).get();
983 PC = buildPromiseCall(*this, Promise, Loc, "return_void", None);
984 }
985 if (PC.isInvalid())
986 return StmtError();
987
988 Expr *PCE = ActOnFinishFullExpr(PC.get(), /*DiscardedValue*/ false).get();
989
990 Stmt *Res = new (Context) CoreturnStmt(Loc, E, PCE, IsImplicit);
991 return Res;
992}
993
994/// Look up the std::nothrow object.
995static Expr *buildStdNoThrowDeclRef(Sema &S, SourceLocation Loc) {
996 NamespaceDecl *Std = S.getStdNamespace();
997 assert(Std && "Should already be diagnosed")((Std && "Should already be diagnosed") ? static_cast
<void> (0) : __assert_fail ("Std && \"Should already be diagnosed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 997, __PRETTY_FUNCTION__))
;
998
999 LookupResult Result(S, &S.PP.getIdentifierTable().get("nothrow"), Loc,
1000 Sema::LookupOrdinaryName);
1001 if (!S.LookupQualifiedName(Result, Std)) {
1002 // FIXME: <experimental/coroutine> should have been included already.
1003 // If we require it to include <new> then this diagnostic is no longer
1004 // needed.
1005 S.Diag(Loc, diag::err_implicit_coroutine_std_nothrow_type_not_found);
1006 return nullptr;
1007 }
1008
1009 auto *VD = Result.getAsSingle<VarDecl>();
1010 if (!VD) {
1011 Result.suppressDiagnostics();
1012 // We found something weird. Complain about the first thing we found.
1013 NamedDecl *Found = *Result.begin();
1014 S.Diag(Found->getLocation(), diag::err_malformed_std_nothrow);
1015 return nullptr;
1016 }
1017
1018 ExprResult DR = S.BuildDeclRefExpr(VD, VD->getType(), VK_LValue, Loc);
1019 if (DR.isInvalid())
1020 return nullptr;
1021
1022 return DR.get();
1023}
1024
1025// Find an appropriate delete for the promise.
1026static FunctionDecl *findDeleteForPromise(Sema &S, SourceLocation Loc,
1027 QualType PromiseType) {
1028 FunctionDecl *OperatorDelete = nullptr;
1029
1030 DeclarationName DeleteName =
1031 S.Context.DeclarationNames.getCXXOperatorName(OO_Delete);
1032
1033 auto *PointeeRD = PromiseType->getAsCXXRecordDecl();
1034 assert(PointeeRD && "PromiseType must be a CxxRecordDecl type")((PointeeRD && "PromiseType must be a CxxRecordDecl type"
) ? static_cast<void> (0) : __assert_fail ("PointeeRD && \"PromiseType must be a CxxRecordDecl type\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1034, __PRETTY_FUNCTION__))
;
1035
1036 if (S.FindDeallocationFunction(Loc, PointeeRD, DeleteName, OperatorDelete))
1037 return nullptr;
1038
1039 if (!OperatorDelete) {
1040 // Look for a global declaration.
1041 const bool CanProvideSize = S.isCompleteType(Loc, PromiseType);
1042 const bool Overaligned = false;
1043 OperatorDelete = S.FindUsualDeallocationFunction(Loc, CanProvideSize,
1044 Overaligned, DeleteName);
1045 }
1046 S.MarkFunctionReferenced(Loc, OperatorDelete);
1047 return OperatorDelete;
1048}
1049
1050
1051void Sema::CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body) {
1052 FunctionScopeInfo *Fn = getCurFunction();
1053 assert(Fn && Fn->isCoroutine() && "not a coroutine")((Fn && Fn->isCoroutine() && "not a coroutine"
) ? static_cast<void> (0) : __assert_fail ("Fn && Fn->isCoroutine() && \"not a coroutine\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1053, __PRETTY_FUNCTION__))
;
1054 if (!Body) {
1055 assert(FD->isInvalidDecl() &&((FD->isInvalidDecl() && "a null body is only allowed for invalid declarations"
) ? static_cast<void> (0) : __assert_fail ("FD->isInvalidDecl() && \"a null body is only allowed for invalid declarations\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1056, __PRETTY_FUNCTION__))
1056 "a null body is only allowed for invalid declarations")((FD->isInvalidDecl() && "a null body is only allowed for invalid declarations"
) ? static_cast<void> (0) : __assert_fail ("FD->isInvalidDecl() && \"a null body is only allowed for invalid declarations\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1056, __PRETTY_FUNCTION__))
;
1057 return;
1058 }
1059 // We have a function that uses coroutine keywords, but we failed to build
1060 // the promise type.
1061 if (!Fn->CoroutinePromise)
1062 return FD->setInvalidDecl();
1063
1064 if (isa<CoroutineBodyStmt>(Body)) {
1065 // Nothing todo. the body is already a transformed coroutine body statement.
1066 return;
1067 }
1068
1069 // Coroutines [stmt.return]p1:
1070 // A return statement shall not appear in a coroutine.
1071 if (Fn->FirstReturnLoc.isValid()) {
1072 assert(Fn->FirstCoroutineStmtLoc.isValid() &&((Fn->FirstCoroutineStmtLoc.isValid() && "first coroutine location not set"
) ? static_cast<void> (0) : __assert_fail ("Fn->FirstCoroutineStmtLoc.isValid() && \"first coroutine location not set\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1073, __PRETTY_FUNCTION__))
1073 "first coroutine location not set")((Fn->FirstCoroutineStmtLoc.isValid() && "first coroutine location not set"
) ? static_cast<void> (0) : __assert_fail ("Fn->FirstCoroutineStmtLoc.isValid() && \"first coroutine location not set\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1073, __PRETTY_FUNCTION__))
;
1074 Diag(Fn->FirstReturnLoc, diag::err_return_in_coroutine);
1075 Diag(Fn->FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
1076 << Fn->getFirstCoroutineStmtKeyword();
1077 }
1078 CoroutineStmtBuilder Builder(*this, *FD, *Fn, Body);
1079 if (Builder.isInvalid() || !Builder.buildStatements())
1080 return FD->setInvalidDecl();
1081
1082 // Build body for the coroutine wrapper statement.
1083 Body = CoroutineBodyStmt::Create(Context, Builder);
1084}
1085
1086CoroutineStmtBuilder::CoroutineStmtBuilder(Sema &S, FunctionDecl &FD,
1087 sema::FunctionScopeInfo &Fn,
1088 Stmt *Body)
1089 : S(S), FD(FD), Fn(Fn), Loc(FD.getLocation()),
1090 IsPromiseDependentType(
1091 !Fn.CoroutinePromise ||
1092 Fn.CoroutinePromise->getType()->isDependentType()) {
1093 this->Body = Body;
1094
1095 for (auto KV : Fn.CoroutineParameterMoves)
1096 this->ParamMovesVector.push_back(KV.second);
1097 this->ParamMoves = this->ParamMovesVector;
1098
1099 if (!IsPromiseDependentType) {
1100 PromiseRecordDecl = Fn.CoroutinePromise->getType()->getAsCXXRecordDecl();
1101 assert(PromiseRecordDecl && "Type should have already been checked")((PromiseRecordDecl && "Type should have already been checked"
) ? static_cast<void> (0) : __assert_fail ("PromiseRecordDecl && \"Type should have already been checked\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1101, __PRETTY_FUNCTION__))
;
1102 }
1103 this->IsValid = makePromiseStmt() && makeInitialAndFinalSuspend();
1104}
1105
1106bool CoroutineStmtBuilder::buildStatements() {
1107 assert(this->IsValid && "coroutine already invalid")((this->IsValid && "coroutine already invalid") ? static_cast
<void> (0) : __assert_fail ("this->IsValid && \"coroutine already invalid\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1107, __PRETTY_FUNCTION__))
;
1108 this->IsValid = makeReturnObject();
1109 if (this->IsValid && !IsPromiseDependentType)
1110 buildDependentStatements();
1111 return this->IsValid;
1112}
1113
1114bool CoroutineStmtBuilder::buildDependentStatements() {
1115 assert(this->IsValid && "coroutine already invalid")((this->IsValid && "coroutine already invalid") ? static_cast
<void> (0) : __assert_fail ("this->IsValid && \"coroutine already invalid\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1115, __PRETTY_FUNCTION__))
;
1116 assert(!this->IsPromiseDependentType &&((!this->IsPromiseDependentType && "coroutine cannot have a dependent promise type"
) ? static_cast<void> (0) : __assert_fail ("!this->IsPromiseDependentType && \"coroutine cannot have a dependent promise type\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1117, __PRETTY_FUNCTION__))
1117 "coroutine cannot have a dependent promise type")((!this->IsPromiseDependentType && "coroutine cannot have a dependent promise type"
) ? static_cast<void> (0) : __assert_fail ("!this->IsPromiseDependentType && \"coroutine cannot have a dependent promise type\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1117, __PRETTY_FUNCTION__))
;
1118 this->IsValid = makeOnException() && makeOnFallthrough() &&
1119 makeGroDeclAndReturnStmt() && makeReturnOnAllocFailure() &&
1120 makeNewAndDeleteExpr();
1121 return this->IsValid;
1122}
1123
1124bool CoroutineStmtBuilder::makePromiseStmt() {
1125 // Form a declaration statement for the promise declaration, so that AST
1126 // visitors can more easily find it.
1127 StmtResult PromiseStmt =
1128 S.ActOnDeclStmt(S.ConvertDeclToDeclGroup(Fn.CoroutinePromise), Loc, Loc);
1129 if (PromiseStmt.isInvalid())
1130 return false;
1131
1132 this->Promise = PromiseStmt.get();
1133 return true;
1134}
1135
1136bool CoroutineStmtBuilder::makeInitialAndFinalSuspend() {
1137 if (Fn.hasInvalidCoroutineSuspends())
1138 return false;
1139 this->InitialSuspend = cast<Expr>(Fn.CoroutineSuspends.first);
1140 this->FinalSuspend = cast<Expr>(Fn.CoroutineSuspends.second);
1141 return true;
1142}
1143
1144static bool diagReturnOnAllocFailure(Sema &S, Expr *E,
1145 CXXRecordDecl *PromiseRecordDecl,
1146 FunctionScopeInfo &Fn) {
1147 auto Loc = E->getExprLoc();
1148 if (auto *DeclRef = dyn_cast_or_null<DeclRefExpr>(E)) {
1149 auto *Decl = DeclRef->getDecl();
1150 if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(Decl)) {
1151 if (Method->isStatic())
1152 return true;
1153 else
1154 Loc = Decl->getLocation();
1155 }
1156 }
1157
1158 S.Diag(
1159 Loc,
1160 diag::err_coroutine_promise_get_return_object_on_allocation_failure)
1161 << PromiseRecordDecl;
1162 S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
1163 << Fn.getFirstCoroutineStmtKeyword();
1164 return false;
1165}
1166
1167bool CoroutineStmtBuilder::makeReturnOnAllocFailure() {
1168 assert(!IsPromiseDependentType &&((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1169, __PRETTY_FUNCTION__))
1169 "cannot make statement while the promise type is dependent")((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1169, __PRETTY_FUNCTION__))
;
1170
1171 // [dcl.fct.def.coroutine]/8
1172 // The unqualified-id get_return_object_on_allocation_failure is looked up in
1173 // the scope of class P by class member access lookup (3.4.5). ...
1174 // If an allocation function returns nullptr, ... the coroutine return value
1175 // is obtained by a call to ... get_return_object_on_allocation_failure().
1176
1177 DeclarationName DN =
1178 S.PP.getIdentifierInfo("get_return_object_on_allocation_failure");
1179 LookupResult Found(S, DN, Loc, Sema::LookupMemberName);
1180 if (!S.LookupQualifiedName(Found, PromiseRecordDecl))
1181 return true;
1182
1183 CXXScopeSpec SS;
1184 ExprResult DeclNameExpr =
1185 S.BuildDeclarationNameExpr(SS, Found, /*NeedsADL=*/false);
1186 if (DeclNameExpr.isInvalid())
1187 return false;
1188
1189 if (!diagReturnOnAllocFailure(S, DeclNameExpr.get(), PromiseRecordDecl, Fn))
1190 return false;
1191
1192 ExprResult ReturnObjectOnAllocationFailure =
1193 S.BuildCallExpr(nullptr, DeclNameExpr.get(), Loc, {}, Loc);
1194 if (ReturnObjectOnAllocationFailure.isInvalid())
1195 return false;
1196
1197 StmtResult ReturnStmt =
1198 S.BuildReturnStmt(Loc, ReturnObjectOnAllocationFailure.get());
1199 if (ReturnStmt.isInvalid()) {
1200 S.Diag(Found.getFoundDecl()->getLocation(), diag::note_member_declared_here)
1201 << DN;
1202 S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
1203 << Fn.getFirstCoroutineStmtKeyword();
1204 return false;
1205 }
1206
1207 this->ReturnStmtOnAllocFailure = ReturnStmt.get();
1208 return true;
1209}
1210
1211bool CoroutineStmtBuilder::makeNewAndDeleteExpr() {
1212 // Form and check allocation and deallocation calls.
1213 assert(!IsPromiseDependentType &&((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1214, __PRETTY_FUNCTION__))
1214 "cannot make statement while the promise type is dependent")((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1214, __PRETTY_FUNCTION__))
;
1215 QualType PromiseType = Fn.CoroutinePromise->getType();
1216
1217 if (S.RequireCompleteType(Loc, PromiseType, diag::err_incomplete_type))
1218 return false;
1219
1220 const bool RequiresNoThrowAlloc = ReturnStmtOnAllocFailure != nullptr;
1221
1222 // [dcl.fct.def.coroutine]/7
1223 // Lookup allocation functions using a parameter list composed of the
1224 // requested size of the coroutine state being allocated, followed by
1225 // the coroutine function's arguments. If a matching allocation function
1226 // exists, use it. Otherwise, use an allocation function that just takes
1227 // the requested size.
1228
1229 FunctionDecl *OperatorNew = nullptr;
1230 FunctionDecl *OperatorDelete = nullptr;
1231 FunctionDecl *UnusedResult = nullptr;
1232 bool PassAlignment = false;
1233 SmallVector<Expr *, 1> PlacementArgs;
1234
1235 // [dcl.fct.def.coroutine]/7
1236 // "The allocation function’s name is looked up in the scope of P.
1237 // [...] If the lookup finds an allocation function in the scope of P,
1238 // overload resolution is performed on a function call created by assembling
1239 // an argument list. The first argument is the amount of space requested,
1240 // and has type std::size_t. The lvalues p1 ... pn are the succeeding
1241 // arguments."
1242 //
1243 // ...where "p1 ... pn" are defined earlier as:
1244 //
1245 // [dcl.fct.def.coroutine]/3
1246 // "For a coroutine f that is a non-static member function, let P1 denote the
1247 // type of the implicit object parameter (13.3.1) and P2 ... Pn be the types
1248 // of the function parameters; otherwise let P1 ... Pn be the types of the
1249 // function parameters. Let p1 ... pn be lvalues denoting those objects."
1250 if (auto *MD = dyn_cast<CXXMethodDecl>(&FD)) {
1251 if (MD->isInstance() && !isLambdaCallOperator(MD)) {
1252 ExprResult ThisExpr = S.ActOnCXXThis(Loc);
1253 if (ThisExpr.isInvalid())
1254 return false;
1255 ThisExpr = S.CreateBuiltinUnaryOp(Loc, UO_Deref, ThisExpr.get());
1256 if (ThisExpr.isInvalid())
1257 return false;
1258 PlacementArgs.push_back(ThisExpr.get());
1259 }
1260 }
1261 for (auto *PD : FD.parameters()) {
1262 if (PD->getType()->isDependentType())
1263 continue;
1264
1265 // Build a reference to the parameter.
1266 auto PDLoc = PD->getLocation();
1267 ExprResult PDRefExpr =
1268 S.BuildDeclRefExpr(PD, PD->getOriginalType().getNonReferenceType(),
1269 ExprValueKind::VK_LValue, PDLoc);
1270 if (PDRefExpr.isInvalid())
1271 return false;
1272
1273 PlacementArgs.push_back(PDRefExpr.get());
1274 }
1275 S.FindAllocationFunctions(Loc, SourceRange(), /*NewScope*/ Sema::AFS_Class,
1276 /*DeleteScope*/ Sema::AFS_Both, PromiseType,
1277 /*isArray*/ false, PassAlignment, PlacementArgs,
1278 OperatorNew, UnusedResult, /*Diagnose*/ false);
1279
1280 // [dcl.fct.def.coroutine]/7
1281 // "If no matching function is found, overload resolution is performed again
1282 // on a function call created by passing just the amount of space required as
1283 // an argument of type std::size_t."
1284 if (!OperatorNew && !PlacementArgs.empty()) {
1285 PlacementArgs.clear();
1286 S.FindAllocationFunctions(Loc, SourceRange(), /*NewScope*/ Sema::AFS_Class,
1287 /*DeleteScope*/ Sema::AFS_Both, PromiseType,
1288 /*isArray*/ false, PassAlignment, PlacementArgs,
1289 OperatorNew, UnusedResult, /*Diagnose*/ false);
1290 }
1291
1292 // [dcl.fct.def.coroutine]/7
1293 // "The allocation function’s name is looked up in the scope of P. If this
1294 // lookup fails, the allocation function’s name is looked up in the global
1295 // scope."
1296 if (!OperatorNew) {
1297 S.FindAllocationFunctions(Loc, SourceRange(), /*NewScope*/ Sema::AFS_Global,
1298 /*DeleteScope*/ Sema::AFS_Both, PromiseType,
1299 /*isArray*/ false, PassAlignment, PlacementArgs,
1300 OperatorNew, UnusedResult);
1301 }
1302
1303 bool IsGlobalOverload =
1304 OperatorNew && !isa<CXXRecordDecl>(OperatorNew->getDeclContext());
1305 // If we didn't find a class-local new declaration and non-throwing new
1306 // was is required then we need to lookup the non-throwing global operator
1307 // instead.
1308 if (RequiresNoThrowAlloc && (!OperatorNew || IsGlobalOverload)) {
1309 auto *StdNoThrow = buildStdNoThrowDeclRef(S, Loc);
1310 if (!StdNoThrow)
1311 return false;
1312 PlacementArgs = {StdNoThrow};
1313 OperatorNew = nullptr;
1314 S.FindAllocationFunctions(Loc, SourceRange(), /*NewScope*/ Sema::AFS_Both,
1315 /*DeleteScope*/ Sema::AFS_Both, PromiseType,
1316 /*isArray*/ false, PassAlignment, PlacementArgs,
1317 OperatorNew, UnusedResult);
1318 }
1319
1320 if (!OperatorNew)
1321 return false;
1322
1323 if (RequiresNoThrowAlloc) {
1324 const auto *FT = OperatorNew->getType()->castAs<FunctionProtoType>();
1325 if (!FT->isNothrow(/*ResultIfDependent*/ false)) {
1326 S.Diag(OperatorNew->getLocation(),
1327 diag::err_coroutine_promise_new_requires_nothrow)
1328 << OperatorNew;
1329 S.Diag(Loc, diag::note_coroutine_promise_call_implicitly_required)
1330 << OperatorNew;
1331 return false;
1332 }
1333 }
1334
1335 if ((OperatorDelete = findDeleteForPromise(S, Loc, PromiseType)) == nullptr)
1336 return false;
1337
1338 Expr *FramePtr =
1339 buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_frame, {});
1340
1341 Expr *FrameSize =
1342 buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_size, {});
1343
1344 // Make new call.
1345
1346 ExprResult NewRef =
1347 S.BuildDeclRefExpr(OperatorNew, OperatorNew->getType(), VK_LValue, Loc);
1348 if (NewRef.isInvalid())
1349 return false;
1350
1351 SmallVector<Expr *, 2> NewArgs(1, FrameSize);
1352 for (auto Arg : PlacementArgs)
1353 NewArgs.push_back(Arg);
1354
1355 ExprResult NewExpr =
1356 S.BuildCallExpr(S.getCurScope(), NewRef.get(), Loc, NewArgs, Loc);
1357 NewExpr = S.ActOnFinishFullExpr(NewExpr.get(), /*DiscardedValue*/ false);
1358 if (NewExpr.isInvalid())
1359 return false;
1360
1361 // Make delete call.
1362
1363 QualType OpDeleteQualType = OperatorDelete->getType();
1364
1365 ExprResult DeleteRef =
1366 S.BuildDeclRefExpr(OperatorDelete, OpDeleteQualType, VK_LValue, Loc);
1367 if (DeleteRef.isInvalid())
1368 return false;
1369
1370 Expr *CoroFree =
1371 buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_free, {FramePtr});
1372
1373 SmallVector<Expr *, 2> DeleteArgs{CoroFree};
1374
1375 // Check if we need to pass the size.
1376 const auto *OpDeleteType =
1377 OpDeleteQualType.getTypePtr()->castAs<FunctionProtoType>();
1378 if (OpDeleteType->getNumParams() > 1)
1379 DeleteArgs.push_back(FrameSize);
1380
1381 ExprResult DeleteExpr =
1382 S.BuildCallExpr(S.getCurScope(), DeleteRef.get(), Loc, DeleteArgs, Loc);
1383 DeleteExpr =
1384 S.ActOnFinishFullExpr(DeleteExpr.get(), /*DiscardedValue*/ false);
1385 if (DeleteExpr.isInvalid())
1386 return false;
1387
1388 this->Allocate = NewExpr.get();
1389 this->Deallocate = DeleteExpr.get();
1390
1391 return true;
1392}
1393
1394bool CoroutineStmtBuilder::makeOnFallthrough() {
1395 assert(!IsPromiseDependentType &&((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1396, __PRETTY_FUNCTION__))
1396 "cannot make statement while the promise type is dependent")((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1396, __PRETTY_FUNCTION__))
;
1397
1398 // [dcl.fct.def.coroutine]/4
1399 // The unqualified-ids 'return_void' and 'return_value' are looked up in
1400 // the scope of class P. If both are found, the program is ill-formed.
1401 bool HasRVoid, HasRValue;
1402 LookupResult LRVoid =
1403 lookupMember(S, "return_void", PromiseRecordDecl, Loc, HasRVoid);
1404 LookupResult LRValue =
1405 lookupMember(S, "return_value", PromiseRecordDecl, Loc, HasRValue);
1406
1407 StmtResult Fallthrough;
1408 if (HasRVoid && HasRValue) {
1409 // FIXME Improve this diagnostic
1410 S.Diag(FD.getLocation(),
1411 diag::err_coroutine_promise_incompatible_return_functions)
1412 << PromiseRecordDecl;
1413 S.Diag(LRVoid.getRepresentativeDecl()->getLocation(),
1414 diag::note_member_first_declared_here)
1415 << LRVoid.getLookupName();
1416 S.Diag(LRValue.getRepresentativeDecl()->getLocation(),
1417 diag::note_member_first_declared_here)
1418 << LRValue.getLookupName();
1419 return false;
1420 } else if (!HasRVoid && !HasRValue) {
1421 // FIXME: The PDTS currently specifies this case as UB, not ill-formed.
1422 // However we still diagnose this as an error since until the PDTS is fixed.
1423 S.Diag(FD.getLocation(),
1424 diag::err_coroutine_promise_requires_return_function)
1425 << PromiseRecordDecl;
1426 S.Diag(PromiseRecordDecl->getLocation(), diag::note_defined_here)
1427 << PromiseRecordDecl;
1428 return false;
1429 } else if (HasRVoid) {
1430 // If the unqualified-id return_void is found, flowing off the end of a
1431 // coroutine is equivalent to a co_return with no operand. Otherwise,
1432 // flowing off the end of a coroutine results in undefined behavior.
1433 Fallthrough = S.BuildCoreturnStmt(FD.getLocation(), nullptr,
1434 /*IsImplicit*/false);
1435 Fallthrough = S.ActOnFinishFullStmt(Fallthrough.get());
1436 if (Fallthrough.isInvalid())
1437 return false;
1438 }
1439
1440 this->OnFallthrough = Fallthrough.get();
1441 return true;
1442}
1443
1444bool CoroutineStmtBuilder::makeOnException() {
1445 // Try to form 'p.unhandled_exception();'
1446 assert(!IsPromiseDependentType &&((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1447, __PRETTY_FUNCTION__))
1447 "cannot make statement while the promise type is dependent")((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1447, __PRETTY_FUNCTION__))
;
1448
1449 const bool RequireUnhandledException = S.getLangOpts().CXXExceptions;
1450
1451 if (!lookupMember(S, "unhandled_exception", PromiseRecordDecl, Loc)) {
1452 auto DiagID =
1453 RequireUnhandledException
1454 ? diag::err_coroutine_promise_unhandled_exception_required
1455 : diag::
1456 warn_coroutine_promise_unhandled_exception_required_with_exceptions;
1457 S.Diag(Loc, DiagID) << PromiseRecordDecl;
1458 S.Diag(PromiseRecordDecl->getLocation(), diag::note_defined_here)
1459 << PromiseRecordDecl;
1460 return !RequireUnhandledException;
1461 }
1462
1463 // If exceptions are disabled, don't try to build OnException.
1464 if (!S.getLangOpts().CXXExceptions)
1465 return true;
1466
1467 ExprResult UnhandledException = buildPromiseCall(S, Fn.CoroutinePromise, Loc,
1468 "unhandled_exception", None);
1469 UnhandledException = S.ActOnFinishFullExpr(UnhandledException.get(), Loc,
1470 /*DiscardedValue*/ false);
1471 if (UnhandledException.isInvalid())
1472 return false;
1473
1474 // Since the body of the coroutine will be wrapped in try-catch, it will
1475 // be incompatible with SEH __try if present in a function.
1476 if (!S.getLangOpts().Borland && Fn.FirstSEHTryLoc.isValid()) {
1477 S.Diag(Fn.FirstSEHTryLoc, diag::err_seh_in_a_coroutine_with_cxx_exceptions);
1478 S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
1479 << Fn.getFirstCoroutineStmtKeyword();
1480 return false;
1481 }
1482
1483 this->OnException = UnhandledException.get();
1484 return true;
1485}
1486
1487bool CoroutineStmtBuilder::makeReturnObject() {
1488 // Build implicit 'p.get_return_object()' expression and form initialization
1489 // of return type from it.
1490 ExprResult ReturnObject =
1491 buildPromiseCall(S, Fn.CoroutinePromise, Loc, "get_return_object", None);
1492 if (ReturnObject.isInvalid())
1493 return false;
1494
1495 this->ReturnValue = ReturnObject.get();
1496 return true;
1497}
1498
1499static void noteMemberDeclaredHere(Sema &S, Expr *E, FunctionScopeInfo &Fn) {
1500 if (auto *MbrRef = dyn_cast<CXXMemberCallExpr>(E)) {
1501 auto *MethodDecl = MbrRef->getMethodDecl();
1502 S.Diag(MethodDecl->getLocation(), diag::note_member_declared_here)
1503 << MethodDecl;
1504 }
1505 S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
1506 << Fn.getFirstCoroutineStmtKeyword();
1507}
1508
1509bool CoroutineStmtBuilder::makeGroDeclAndReturnStmt() {
1510 assert(!IsPromiseDependentType &&((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1511, __PRETTY_FUNCTION__))
1511 "cannot make statement while the promise type is dependent")((!IsPromiseDependentType && "cannot make statement while the promise type is dependent"
) ? static_cast<void> (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1511, __PRETTY_FUNCTION__))
;
1512 assert(this->ReturnValue && "ReturnValue must be already formed")((this->ReturnValue && "ReturnValue must be already formed"
) ? static_cast<void> (0) : __assert_fail ("this->ReturnValue && \"ReturnValue must be already formed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1512, __PRETTY_FUNCTION__))
;
1513
1514 QualType const GroType = this->ReturnValue->getType();
1515 assert(!GroType->isDependentType() &&((!GroType->isDependentType() && "get_return_object type must no longer be dependent"
) ? static_cast<void> (0) : __assert_fail ("!GroType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1516, __PRETTY_FUNCTION__))
1516 "get_return_object type must no longer be dependent")((!GroType->isDependentType() && "get_return_object type must no longer be dependent"
) ? static_cast<void> (0) : __assert_fail ("!GroType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1516, __PRETTY_FUNCTION__))
;
1517
1518 QualType const FnRetType = FD.getReturnType();
1519 assert(!FnRetType->isDependentType() &&((!FnRetType->isDependentType() && "get_return_object type must no longer be dependent"
) ? static_cast<void> (0) : __assert_fail ("!FnRetType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1520, __PRETTY_FUNCTION__))
1520 "get_return_object type must no longer be dependent")((!FnRetType->isDependentType() && "get_return_object type must no longer be dependent"
) ? static_cast<void> (0) : __assert_fail ("!FnRetType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1520, __PRETTY_FUNCTION__))
;
1521
1522 if (FnRetType->isVoidType()) {
1523 ExprResult Res =
1524 S.ActOnFinishFullExpr(this->ReturnValue, Loc, /*DiscardedValue*/ false);
1525 if (Res.isInvalid())
1526 return false;
1527
1528 this->ResultDecl = Res.get();
1529 return true;
1530 }
1531
1532 if (GroType->isVoidType()) {
1533 // Trigger a nice error message.
1534 InitializedEntity Entity =
1535 InitializedEntity::InitializeResult(Loc, FnRetType, false);
1536 S.PerformMoveOrCopyInitialization(Entity, nullptr, FnRetType, ReturnValue);
1537 noteMemberDeclaredHere(S, ReturnValue, Fn);
1538 return false;
1539 }
1540
1541 auto *GroDecl = VarDecl::Create(
1542 S.Context, &FD, FD.getLocation(), FD.getLocation(),
1543 &S.PP.getIdentifierTable().get("__coro_gro"), GroType,
1544 S.Context.getTrivialTypeSourceInfo(GroType, Loc), SC_None);
1545
1546 S.CheckVariableDeclarationType(GroDecl);
1547 if (GroDecl->isInvalidDecl())
1548 return false;
1549
1550 InitializedEntity Entity = InitializedEntity::InitializeVariable(GroDecl);
1551 ExprResult Res = S.PerformMoveOrCopyInitialization(Entity, nullptr, GroType,
1552 this->ReturnValue);
1553 if (Res.isInvalid())
1554 return false;
1555
1556 Res = S.ActOnFinishFullExpr(Res.get(), /*DiscardedValue*/ false);
1557 if (Res.isInvalid())
1558 return false;
1559
1560 S.AddInitializerToDecl(GroDecl, Res.get(),
1561 /*DirectInit=*/false);
1562
1563 S.FinalizeDeclaration(GroDecl);
1564
1565 // Form a declaration statement for the return declaration, so that AST
1566 // visitors can more easily find it.
1567 StmtResult GroDeclStmt =
1568 S.ActOnDeclStmt(S.ConvertDeclToDeclGroup(GroDecl), Loc, Loc);
1569 if (GroDeclStmt.isInvalid())
1570 return false;
1571
1572 this->ResultDecl = GroDeclStmt.get();
1573
1574 ExprResult declRef = S.BuildDeclRefExpr(GroDecl, GroType, VK_LValue, Loc);
1575 if (declRef.isInvalid())
1576 return false;
1577
1578 StmtResult ReturnStmt = S.BuildReturnStmt(Loc, declRef.get());
1579 if (ReturnStmt.isInvalid()) {
1580 noteMemberDeclaredHere(S, ReturnValue, Fn);
1581 return false;
1582 }
1583 if (cast<clang::ReturnStmt>(ReturnStmt.get())->getNRVOCandidate() == GroDecl)
1584 GroDecl->setNRVOVariable(true);
1585
1586 this->ReturnStmt = ReturnStmt.get();
1587 return true;
1588}
1589
1590// Create a static_cast\<T&&>(expr).
1591static Expr *castForMoving(Sema &S, Expr *E, QualType T = QualType()) {
1592 if (T.isNull())
1593 T = E->getType();
1594 QualType TargetType = S.BuildReferenceType(
1595 T, /*SpelledAsLValue*/ false, SourceLocation(), DeclarationName());
1596 SourceLocation ExprLoc = E->getBeginLoc();
1597 TypeSourceInfo *TargetLoc =
1598 S.Context.getTrivialTypeSourceInfo(TargetType, ExprLoc);
1599
1600 return S
1601 .BuildCXXNamedCast(ExprLoc, tok::kw_static_cast, TargetLoc, E,
1602 SourceRange(ExprLoc, ExprLoc), E->getSourceRange())
1603 .get();
1604}
1605
1606/// Build a variable declaration for move parameter.
1607static VarDecl *buildVarDecl(Sema &S, SourceLocation Loc, QualType Type,
1608 IdentifierInfo *II) {
1609 TypeSourceInfo *TInfo = S.Context.getTrivialTypeSourceInfo(Type, Loc);
1610 VarDecl *Decl = VarDecl::Create(S.Context, S.CurContext, Loc, Loc, II, Type,
1611 TInfo, SC_None);
1612 Decl->setImplicit();
1613 return Decl;
1614}
1615
1616// Build statements that move coroutine function parameters to the coroutine
1617// frame, and store them on the function scope info.
1618bool Sema::buildCoroutineParameterMoves(SourceLocation Loc) {
1619 assert(isa<FunctionDecl>(CurContext) && "not in a function scope")((isa<FunctionDecl>(CurContext) && "not in a function scope"
) ? static_cast<void> (0) : __assert_fail ("isa<FunctionDecl>(CurContext) && \"not in a function scope\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/Sema/SemaCoroutine.cpp"
, 1619, __PRETTY_FUNCTION__))
;
1620 auto *FD = cast<FunctionDecl>(CurContext);
1621
1622 auto *ScopeInfo = getCurFunction();
1623 if (!ScopeInfo->CoroutineParameterMoves.empty())
1624 return false;
1625
1626 for (auto *PD : FD->parameters()) {
1627 if (PD->getType()->isDependentType())
1628 continue;
1629
1630 ExprResult PDRefExpr =
1631 BuildDeclRefExpr(PD, PD->getType().getNonReferenceType(),
1632 ExprValueKind::VK_LValue, Loc); // FIXME: scope?
1633 if (PDRefExpr.isInvalid())
1634 return false;
1635
1636 Expr *CExpr = nullptr;
1637 if (PD->getType()->getAsCXXRecordDecl() ||
1638 PD->getType()->isRValueReferenceType())
1639 CExpr = castForMoving(*this, PDRefExpr.get());
1640 else
1641 CExpr = PDRefExpr.get();
1642
1643 auto D = buildVarDecl(*this, Loc, PD->getType(), PD->getIdentifier());
1644 AddInitializerToDecl(D, CExpr, /*DirectInit=*/true);
1645
1646 // Convert decl to a statement.
1647 StmtResult Stmt = ActOnDeclStmt(ConvertDeclToDeclGroup(D), Loc, Loc);
1648 if (Stmt.isInvalid())
1649 return false;
1650
1651 ScopeInfo->CoroutineParameterMoves.insert(std::make_pair(PD, Stmt.get()));
1652 }
1653 return true;
1654}
1655
1656StmtResult Sema::BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs Args) {
1657 CoroutineBodyStmt *Res = CoroutineBodyStmt::Create(Context, Args);
1658 if (!Res)
1659 return StmtError();
1660 return Res;
1661}
1662
1663ClassTemplateDecl *Sema::lookupCoroutineTraits(SourceLocation KwLoc,
1664 SourceLocation FuncLoc) {
1665 if (!StdCoroutineTraitsCache) {
1666 if (auto StdExp = lookupStdExperimentalNamespace()) {
1667 LookupResult Result(*this,
1668 &PP.getIdentifierTable().get("coroutine_traits"),
1669 FuncLoc, LookupOrdinaryName);
1670 if (!LookupQualifiedName(Result, StdExp)) {
1671 Diag(KwLoc, diag::err_implied_coroutine_type_not_found)
1672 << "std::experimental::coroutine_traits";
1673 return nullptr;
1674 }
1675 if (!(StdCoroutineTraitsCache =
1676 Result.getAsSingle<ClassTemplateDecl>())) {
1677 Result.suppressDiagnostics();
1678 NamedDecl *Found = *Result.begin();
1679 Diag(Found->getLocation(), diag::err_malformed_std_coroutine_traits);
1680 return nullptr;
1681 }
1682 }
1683 }
1684 return StdCoroutineTraitsCache;
1685}