[clang] [coroutines][coro_lifetimebound] Detect lifetime issues with lambda captures (PR #77066)
Utkarsh Saxena via cfe-commits
cfe-commits at lists.llvm.org
Tue Jan 16 07:32:57 PST 2024
https://github.com/usx95 updated https://github.com/llvm/llvm-project/pull/77066
>From 3e0d0ab6c4fc6cba68285816a95e423bc18e8e55 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Fri, 5 Jan 2024 10:11:20 +0100
Subject: [PATCH 01/12] [coroutines] Detect lifetime issues with coroutine
lambda captures
---
clang/lib/Sema/SemaInit.cpp | 20 +++++--
clang/test/SemaCXX/coro-lifetimebound.cpp | 64 +++++++++++++++++++++--
2 files changed, 76 insertions(+), 8 deletions(-)
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 60c0e3e74204ec..c100bf11454786 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -12,6 +12,7 @@
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
+#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/ExprOpenMP.h"
@@ -33,6 +34,7 @@
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
@@ -7575,15 +7577,27 @@ static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
Path.pop_back();
};
- if (ObjectArg && implicitObjectParamIsLifetimeBound(Callee))
- VisitLifetimeBoundArg(Callee, ObjectArg);
-
bool CheckCoroCall = false;
if (const auto *RD = Callee->getReturnType()->getAsRecordDecl()) {
CheckCoroCall = RD->hasAttr<CoroLifetimeBoundAttr>() &&
RD->hasAttr<CoroReturnTypeAttr>() &&
!Callee->hasAttr<CoroDisableLifetimeBoundAttr>();
}
+
+ if (ObjectArg) {
+ bool CheckCoroObjArg = CheckCoroCall;
+ // Ignore `__promise.get_return_object()` as it not lifetimebound.
+ if (Callee->getDeclName().isIdentifier() &&
+ Callee->getName() == "get_return_object")
+ CheckCoroObjArg = false;
+ // Coroutine lambda objects with empty capture list are not lifetimebound.
+ if (auto *LE = dyn_cast<LambdaExpr>(ObjectArg->IgnoreImplicit());
+ LE && LE->captures().empty())
+ CheckCoroObjArg = false;
+ if (implicitObjectParamIsLifetimeBound(Callee) || CheckCoroObjArg)
+ VisitLifetimeBoundArg(Callee, ObjectArg);
+ }
+
for (unsigned I = 0,
N = std::min<unsigned>(Callee->getNumParams(), Args.size());
I != N; ++I) {
diff --git a/clang/test/SemaCXX/coro-lifetimebound.cpp b/clang/test/SemaCXX/coro-lifetimebound.cpp
index 3fc7ca70a14a12..319134450e4b6f 100644
--- a/clang/test/SemaCXX/coro-lifetimebound.cpp
+++ b/clang/test/SemaCXX/coro-lifetimebound.cpp
@@ -64,6 +64,10 @@ Co<int> bar_coro(const int &b, int c) {
: bar_coro(0, 1); // expected-warning {{returning address of local temporary object}}
}
+// =============================================================================
+// Lambdas
+// =============================================================================
+namespace lambdas {
void lambdas() {
auto unsafe_lambda = [] [[clang::coro_wrapper]] (int b) {
return foo_coro(b); // expected-warning {{address of stack memory associated with parameter}}
@@ -84,15 +88,47 @@ void lambdas() {
co_return x + co_await foo_coro(b);
};
}
+
+Co<int> lambda_captures() {
+ int a = 1;
+ // Temporary lambda object dies.
+ auto lamb = [a](int x, const int& y) -> Co<int> { // expected-warning {{temporary whose address is used as value of local variable 'lamb'}}
+ co_return x + y + a;
+ }(1, a);
+ // Object dies but it has no capture.
+ auto no_capture = []() -> Co<int> { co_return 1; }();
+ auto bad_no_capture = [](const int& a) -> Co<int> { co_return a; }(1); // expected-warning {{temporary}}
+ // Temporary lambda object with lifetime extension under co_await.
+ int res = co_await [a](int x, const int& y) -> Co<int> {
+ co_return x + y + a;
+ }(1, a);
+ co_return 1;
+}
+} // namespace lambdas
+
// =============================================================================
-// Safe usage when parameters are value
+// Member coroutines
// =============================================================================
-namespace by_value {
-Co<int> value_coro(int b) { co_return co_await foo_coro(b); }
-[[clang::coro_wrapper]] Co<int> wrapper1(int b) { return value_coro(b); }
-[[clang::coro_wrapper]] Co<int> wrapper2(const int& b) { return value_coro(b); }
+namespace member_coroutines{
+struct S {
+ Co<int> member(const int& a) { co_return a; }
+};
+
+Co<int> use() {
+ S s;
+ int a = 1;
+ auto test1 = s.member(1); // expected-warning {{temporary whose address is used as value of local variable}}
+ auto test2 = s.member(a);
+ auto test3 = S{}.member(a); // expected-warning {{temporary whose address is used as value of local variable}}
+ co_return 1;
}
+[[clang::coro_wrapper]] Co<int> wrapper(const int& a) {
+ S s;
+ return s.member(a); // expected-warning {{address of stack memory}}
+}
+} // member_coroutines
+
// =============================================================================
// Lifetime bound but not a Coroutine Return Type: No analysis.
// =============================================================================
@@ -129,4 +165,22 @@ Co<int> foo_wrapper(const int& x) { return foo(x); }
// The call to foo_wrapper is wrapper is safe.
return foo_wrapper(1);
}
+
+struct S{
+[[clang::coro_wrapper, clang::coro_disable_lifetimebound]]
+Co<int> member(const int& x) { return foo(x); }
+};
+
+Co<int> use() {
+ S s;
+ int a = 1;
+ auto test1 = s.member(1); // param is not flagged.
+ auto test2 = S{}.member(a); // 'this' is not flagged.
+ co_return 1;
+}
+
+[[clang::coro_wrapper]] Co<int> return_stack_addr(const int& a) {
+ S s;
+ return s.member(a); // return of stack addr is not flagged.
+}
} // namespace disable_lifetimebound
>From 0d8d78e30dff896880e674240c8bf47b13c527f5 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Fri, 5 Jan 2024 11:39:41 +0100
Subject: [PATCH 02/12] add more test
---
clang/lib/Sema/SemaInit.cpp | 4 ++--
clang/test/SemaCXX/coro-lifetimebound.cpp | 17 +++++++++++++++--
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index c100bf11454786..1aa6be826699bb 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -7586,8 +7586,8 @@ static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
if (ObjectArg) {
bool CheckCoroObjArg = CheckCoroCall;
- // Ignore `__promise.get_return_object()` as it not lifetimebound.
- if (Callee->getDeclName().isIdentifier() &&
+ // Ignore `__promise.get_return_object()` as it is not lifetimebound.
+ if (CheckCoroObjArg && Callee->getDeclName().isIdentifier() &&
Callee->getName() == "get_return_object")
CheckCoroObjArg = false;
// Coroutine lambda objects with empty capture list are not lifetimebound.
diff --git a/clang/test/SemaCXX/coro-lifetimebound.cpp b/clang/test/SemaCXX/coro-lifetimebound.cpp
index 319134450e4b6f..b61013ec057381 100644
--- a/clang/test/SemaCXX/coro-lifetimebound.cpp
+++ b/clang/test/SemaCXX/coro-lifetimebound.cpp
@@ -102,6 +102,10 @@ Co<int> lambda_captures() {
int res = co_await [a](int x, const int& y) -> Co<int> {
co_return x + y + a;
}(1, a);
+ // Lambda object on stack should be fine.
+ auto lamb2 = [a]() -> Co<int> { co_return a; };
+ auto on_stack = lamb2();
+ auto res2 = co_await on_stack;
co_return 1;
}
} // namespace lambdas
@@ -111,7 +115,7 @@ Co<int> lambda_captures() {
// =============================================================================
namespace member_coroutines{
struct S {
- Co<int> member(const int& a) { co_return a; }
+ Co<int> member(const int& a) { co_return a; }
};
Co<int> use() {
@@ -129,6 +133,15 @@ Co<int> use() {
}
} // member_coroutines
+// =============================================================================
+// Safe usage when parameters are value
+// =============================================================================
+namespace by_value {
+Co<int> value_coro(int b) { co_return co_await foo_coro(b); }
+[[clang::coro_wrapper]] Co<int> wrapper1(int b) { return value_coro(b); }
+[[clang::coro_wrapper]] Co<int> wrapper2(const int& b) { return value_coro(b); }
+} // namespace by_value
+
// =============================================================================
// Lifetime bound but not a Coroutine Return Type: No analysis.
// =============================================================================
@@ -158,7 +171,7 @@ CoNoCRT<int> bar(int a) {
namespace disable_lifetimebound {
Co<int> foo(int x) { co_return x; }
-[[clang::coro_wrapper, clang::coro_disable_lifetimebound]]
+[[clang::coro_wrapper, clang::coro_disable_lifetimebound]]
Co<int> foo_wrapper(const int& x) { return foo(x); }
[[clang::coro_wrapper]] Co<int> caller() {
>From e4b801784962946eedf8b5e7c229871588b1621b Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Wed, 10 Jan 2024 13:06:16 +0000
Subject: [PATCH 03/12] Refactor isGetReturnObject()
---
clang/include/clang/Sema/Sema.h | 6 ++++++
clang/lib/Sema/SemaDecl.cpp | 3 +--
clang/lib/Sema/SemaInit.cpp | 3 +--
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 8f44adef38159e..a17a9444d201b6 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -11219,6 +11219,12 @@ class Sema final {
bool buildCoroutineParameterMoves(SourceLocation Loc);
VarDecl *buildCoroutinePromise(SourceLocation Loc);
void CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body);
+ // Heuristaclly tells if the function is promise::get_return_object().
+ static bool isGetReturnObject(const FunctionDecl *FD) {
+ return isa_and_nonnull<CXXMethodDecl>(FD) &&
+ FD->getDeclName().isIdentifier() &&
+ FD->getName().equals("get_return_object") && FD->param_empty();
+ }
// As a clang extension, enforces that a non-coroutine function must be marked
// with [[clang::coro_wrapper]] if it returns a type marked with
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 8e46c4984d93dc..2f93e803d11c69 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -15846,8 +15846,7 @@ void Sema::CheckCoroutineWrapper(FunctionDecl *FD) {
if (!RD || !RD->getUnderlyingDecl()->hasAttr<CoroReturnTypeAttr>())
return;
// Allow `get_return_object()`.
- if (FD->getDeclName().isIdentifier() &&
- FD->getName().equals("get_return_object") && FD->param_empty())
+ if (isGetReturnObject(FD))
return;
if (!FD->hasAttr<CoroWrapperAttr>())
Diag(FD->getLocation(), diag::err_coroutine_return_type) << RD;
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 1aa6be826699bb..848184ff4b724e 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -7587,8 +7587,7 @@ static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
if (ObjectArg) {
bool CheckCoroObjArg = CheckCoroCall;
// Ignore `__promise.get_return_object()` as it is not lifetimebound.
- if (CheckCoroObjArg && Callee->getDeclName().isIdentifier() &&
- Callee->getName() == "get_return_object")
+ if (CheckCoroObjArg && Sema::isGetReturnObject(Callee))
CheckCoroObjArg = false;
// Coroutine lambda objects with empty capture list are not lifetimebound.
if (auto *LE = dyn_cast<LambdaExpr>(ObjectArg->IgnoreImplicit());
>From 4c05d54e07d4f650bf5694a3ddc365078b854627 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Thu, 11 Jan 2024 15:03:41 +0000
Subject: [PATCH 04/12] implicitly add coro_wrapper and
coro_disable_lifetimebound to get_return_object
---
clang/include/clang/Sema/Sema.h | 6 ------
clang/lib/Sema/SemaCoroutine.cpp | 22 ++++++++++++++++++++++
clang/lib/Sema/SemaDecl.cpp | 7 +++++--
clang/lib/Sema/SemaInit.cpp | 3 ---
clang/test/SemaCXX/coro-lifetimebound.cpp | 2 +-
5 files changed, 28 insertions(+), 12 deletions(-)
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index a17a9444d201b6..8f44adef38159e 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -11219,12 +11219,6 @@ class Sema final {
bool buildCoroutineParameterMoves(SourceLocation Loc);
VarDecl *buildCoroutinePromise(SourceLocation Loc);
void CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body);
- // Heuristaclly tells if the function is promise::get_return_object().
- static bool isGetReturnObject(const FunctionDecl *FD) {
- return isa_and_nonnull<CXXMethodDecl>(FD) &&
- FD->getDeclName().isIdentifier() &&
- FD->getName().equals("get_return_object") && FD->param_empty();
- }
// As a clang extension, enforces that a non-coroutine function must be marked
// with [[clang::coro_wrapper]] if it returns a type marked with
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index bee80db8d166a6..0b03ca4ea1fa9c 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -297,6 +297,26 @@ struct ReadySuspendResumeResult {
bool IsInvalid;
};
+// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
+// attributes to `get_return_object`.
+static void handleGetReturnObject(Sema &S, MemberExpr *ME) {
+ if (!ME || !ME->getMemberDecl() || !ME->getMemberDecl()->getAsFunction())
+ return;
+ auto *MD = ME->getMemberDecl()->getAsFunction();
+ auto* RetType = MD->getReturnType()->getAsRecordDecl();
+ if (!RetType || !RetType->hasAttr<CoroReturnTypeAttr>())
+ return;
+ // `get_return_object` should be allowed to return coro_return_type.
+ if (!MD->hasAttr<CoroWrapperAttr>())
+ MD->addAttr(
+ CoroWrapperAttr::CreateImplicit(S.getASTContext(), MD->getLocation()));
+ // Object arg of `__promise.get_return_object()` is not lifetimebound.
+ if (RetType->hasAttr<CoroLifetimeBoundAttr>() &&
+ !MD->hasAttr<CoroDisableLifetimeBoundAttr>())
+ MD->addAttr(CoroDisableLifetimeBoundAttr::CreateImplicit(
+ S.getASTContext(), MD->getLocation()));
+}
+
static ExprResult buildMemberCall(Sema &S, Expr *Base, SourceLocation Loc,
StringRef Name, MultiExprArg Args) {
DeclarationNameInfo NameInfo(&S.PP.getIdentifierTable().get(Name), Loc);
@@ -319,6 +339,8 @@ static ExprResult buildMemberCall(Sema &S, Expr *Base, SourceLocation Loc,
return ExprError();
}
+ if (Name.equals("get_return_object"))
+ handleGetReturnObject(S, dyn_cast<MemberExpr>(Result.get()));
auto EndLoc = Args.empty() ? Loc : Args.back()->getEndLoc();
return S.BuildCallExpr(nullptr, Result.get(), Loc, Args, EndLoc, nullptr);
}
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 2f93e803d11c69..efd3232261123b 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -15845,8 +15845,11 @@ void Sema::CheckCoroutineWrapper(FunctionDecl *FD) {
RecordDecl *RD = FD->getReturnType()->getAsRecordDecl();
if (!RD || !RD->getUnderlyingDecl()->hasAttr<CoroReturnTypeAttr>())
return;
- // Allow `get_return_object()`.
- if (isGetReturnObject(FD))
+ // Allow some_promise_type::get_return_object().
+ // Since we are still in the promise definition, we can only do this
+ // heuristically as the promise may not be yet associated to a coroutine.
+ if (isa<CXXMethodDecl>(FD) && FD->getDeclName().isIdentifier() &&
+ FD->getName().equals("get_return_object") && FD->param_empty())
return;
if (!FD->hasAttr<CoroWrapperAttr>())
Diag(FD->getLocation(), diag::err_coroutine_return_type) << RD;
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 848184ff4b724e..05e71a0b4960ab 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -7586,9 +7586,6 @@ static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
if (ObjectArg) {
bool CheckCoroObjArg = CheckCoroCall;
- // Ignore `__promise.get_return_object()` as it is not lifetimebound.
- if (CheckCoroObjArg && Sema::isGetReturnObject(Callee))
- CheckCoroObjArg = false;
// Coroutine lambda objects with empty capture list are not lifetimebound.
if (auto *LE = dyn_cast<LambdaExpr>(ObjectArg->IgnoreImplicit());
LE && LE->captures().empty())
diff --git a/clang/test/SemaCXX/coro-lifetimebound.cpp b/clang/test/SemaCXX/coro-lifetimebound.cpp
index b61013ec057381..9e96a296562a05 100644
--- a/clang/test/SemaCXX/coro-lifetimebound.cpp
+++ b/clang/test/SemaCXX/coro-lifetimebound.cpp
@@ -180,7 +180,7 @@ Co<int> foo_wrapper(const int& x) { return foo(x); }
}
struct S{
-[[clang::coro_wrapper, clang::coro_disable_lifetimebound]]
+[[clang::coro_wrapper, clang::coro_disable_lifetimebound]]
Co<int> member(const int& x) { return foo(x); }
};
>From 9858f46932f8cf8775c11496b2fe069410c513f4 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Thu, 11 Jan 2024 15:16:46 +0000
Subject: [PATCH 05/12] format
---
clang/lib/Sema/SemaCoroutine.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index 0b03ca4ea1fa9c..ef08e1ee750d17 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -303,7 +303,7 @@ static void handleGetReturnObject(Sema &S, MemberExpr *ME) {
if (!ME || !ME->getMemberDecl() || !ME->getMemberDecl()->getAsFunction())
return;
auto *MD = ME->getMemberDecl()->getAsFunction();
- auto* RetType = MD->getReturnType()->getAsRecordDecl();
+ auto *RetType = MD->getReturnType()->getAsRecordDecl();
if (!RetType || !RetType->hasAttr<CoroReturnTypeAttr>())
return;
// `get_return_object` should be allowed to return coro_return_type.
>From 070fffdd072d30a9d64e7b9bf0f46fcf16cb977a Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Fri, 12 Jan 2024 15:02:09 +0000
Subject: [PATCH 06/12] moved the check to makeReturnObject
---
clang/lib/Sema/SemaCoroutine.cpp | 50 ++++++++++++++++++--------------
1 file changed, 28 insertions(+), 22 deletions(-)
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index ef08e1ee750d17..da4aa658d322ac 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -16,6 +16,7 @@
#include "CoroutineStmtBuilder.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/Decl.h"
+#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/StmtCXX.h"
#include "clang/Basic/Builtins.h"
@@ -297,26 +298,6 @@ struct ReadySuspendResumeResult {
bool IsInvalid;
};
-// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
-// attributes to `get_return_object`.
-static void handleGetReturnObject(Sema &S, MemberExpr *ME) {
- if (!ME || !ME->getMemberDecl() || !ME->getMemberDecl()->getAsFunction())
- return;
- auto *MD = ME->getMemberDecl()->getAsFunction();
- auto *RetType = MD->getReturnType()->getAsRecordDecl();
- if (!RetType || !RetType->hasAttr<CoroReturnTypeAttr>())
- return;
- // `get_return_object` should be allowed to return coro_return_type.
- if (!MD->hasAttr<CoroWrapperAttr>())
- MD->addAttr(
- CoroWrapperAttr::CreateImplicit(S.getASTContext(), MD->getLocation()));
- // Object arg of `__promise.get_return_object()` is not lifetimebound.
- if (RetType->hasAttr<CoroLifetimeBoundAttr>() &&
- !MD->hasAttr<CoroDisableLifetimeBoundAttr>())
- MD->addAttr(CoroDisableLifetimeBoundAttr::CreateImplicit(
- S.getASTContext(), MD->getLocation()));
-}
-
static ExprResult buildMemberCall(Sema &S, Expr *Base, SourceLocation Loc,
StringRef Name, MultiExprArg Args) {
DeclarationNameInfo NameInfo(&S.PP.getIdentifierTable().get(Name), Loc);
@@ -339,8 +320,6 @@ static ExprResult buildMemberCall(Sema &S, Expr *Base, SourceLocation Loc,
return ExprError();
}
- if (Name.equals("get_return_object"))
- handleGetReturnObject(S, dyn_cast<MemberExpr>(Result.get()));
auto EndLoc = Args.empty() ? Loc : Args.back()->getEndLoc();
return S.BuildCallExpr(nullptr, Result.get(), Loc, Args, EndLoc, nullptr);
}
@@ -1818,6 +1797,32 @@ bool CoroutineStmtBuilder::makeOnException() {
return true;
}
+// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
+// attributes to the function `get_return_object`.
+static void handleGetReturnObject(Sema &S, Expr *E) {
+ if(auto* TE = dyn_cast<CXXBindTemporaryExpr>(E))
+ E = TE->getSubExpr();
+ auto* CE = dyn_cast<CallExpr>(E);
+ assert(CE);
+ auto *MD = CE->getDirectCallee();
+ if (!MD)
+ return;
+ // This analysis is done only for types marked with
+ // [[clang::coro_return_type]].
+ auto *RetType = MD->getReturnType()->getAsRecordDecl();
+ if (!RetType || !RetType->hasAttr<CoroReturnTypeAttr>())
+ return;
+ // `get_return_object` should be allowed to return coro_return_type.
+ if (!MD->hasAttr<CoroWrapperAttr>())
+ MD->addAttr(
+ CoroWrapperAttr::CreateImplicit(S.getASTContext(), MD->getLocation()));
+ // Object arg of `__promise.get_return_object()` is not lifetimebound.
+ if (RetType->hasAttr<CoroLifetimeBoundAttr>() &&
+ !MD->hasAttr<CoroDisableLifetimeBoundAttr>())
+ MD->addAttr(CoroDisableLifetimeBoundAttr::CreateImplicit(
+ S.getASTContext(), MD->getLocation()));
+}
+
bool CoroutineStmtBuilder::makeReturnObject() {
// [dcl.fct.def.coroutine]p7
// The expression promise.get_return_object() is used to initialize the
@@ -1827,6 +1832,7 @@ bool CoroutineStmtBuilder::makeReturnObject() {
if (ReturnObject.isInvalid())
return false;
+ handleGetReturnObject(S, ReturnObject.get());
this->ReturnValue = ReturnObject.get();
return true;
}
>From 4052cfa00494847074fce992aad3c727e91a84d2 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Fri, 12 Jan 2024 15:55:02 +0000
Subject: [PATCH 07/12] format
---
clang/lib/Sema/SemaCoroutine.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index da4aa658d322ac..fba8f38b42613d 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -1800,9 +1800,9 @@ bool CoroutineStmtBuilder::makeOnException() {
// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
// attributes to the function `get_return_object`.
static void handleGetReturnObject(Sema &S, Expr *E) {
- if(auto* TE = dyn_cast<CXXBindTemporaryExpr>(E))
+ if (auto *TE = dyn_cast<CXXBindTemporaryExpr>(E))
E = TE->getSubExpr();
- auto* CE = dyn_cast<CallExpr>(E);
+ auto *CE = dyn_cast<CallExpr>(E);
assert(CE);
auto *MD = CE->getDirectCallee();
if (!MD)
>From ac43a7535b7f369f7a529f350ab61a4d3ae825dd Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Mon, 15 Jan 2024 15:00:58 +0100
Subject: [PATCH 08/12] Use cast instead of dyn_cast and assert
Co-authored-by: Chuanqi Xu <yedeng.yd at linux.alibaba.com>
---
clang/lib/Sema/SemaCoroutine.cpp | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index fba8f38b42613d..466c17e11f3977 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -1802,8 +1802,7 @@ bool CoroutineStmtBuilder::makeOnException() {
static void handleGetReturnObject(Sema &S, Expr *E) {
if (auto *TE = dyn_cast<CXXBindTemporaryExpr>(E))
E = TE->getSubExpr();
- auto *CE = dyn_cast<CallExpr>(E);
- assert(CE);
+ auto *CE = cast<CallExpr>(E);
auto *MD = CE->getDirectCallee();
if (!MD)
return;
>From d6ed9900f9ade2162bd0247cf3f765b18d79eb83 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Mon, 15 Jan 2024 15:06:28 +0100
Subject: [PATCH 09/12] Update clang/lib/Sema/SemaCoroutine.cpp
Co-authored-by: Chuanqi Xu <yedeng.yd at linux.alibaba.com>
---
clang/lib/Sema/SemaCoroutine.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index 466c17e11f3977..98c7b54c38350c 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -1798,7 +1798,7 @@ bool CoroutineStmtBuilder::makeOnException() {
}
// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
-// attributes to the function `get_return_object`.
+// attributes to the function `get_return_object` if its return type is marked with `[[clang::coro_return_type]]` to avoid false-positive diagnostic for `get_return_object`.
static void handleGetReturnObject(Sema &S, Expr *E) {
if (auto *TE = dyn_cast<CXXBindTemporaryExpr>(E))
E = TE->getSubExpr();
>From 8b74a3f8359892745e81abcaef361b33f5dc17e6 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Mon, 15 Jan 2024 14:07:04 +0000
Subject: [PATCH 10/12] remove unused include
---
clang/lib/Sema/SemaInit.cpp | 1 -
1 file changed, 1 deletion(-)
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 05e71a0b4960ab..d98108c1b0abc4 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -34,7 +34,6 @@
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
-#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
>From 832db83f7e3854b478bd00404e95ce4cf79a9dd8 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Mon, 15 Jan 2024 14:40:09 +0000
Subject: [PATCH 11/12] format
---
clang/lib/Sema/SemaCoroutine.cpp | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index 98c7b54c38350c..e64fb2cd8ef576 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -1798,7 +1798,9 @@ bool CoroutineStmtBuilder::makeOnException() {
}
// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
-// attributes to the function `get_return_object` if its return type is marked with `[[clang::coro_return_type]]` to avoid false-positive diagnostic for `get_return_object`.
+// attributes to the function `get_return_object` if its return type is marked
+// with `[[clang::coro_return_type]]` to avoid false-positive diagnostic for
+// `get_return_object`.
static void handleGetReturnObject(Sema &S, Expr *E) {
if (auto *TE = dyn_cast<CXXBindTemporaryExpr>(E))
E = TE->getSubExpr();
>From 5080f85ed9adf8141e06d04690b9c24d779df18e Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Tue, 16 Jan 2024 15:32:20 +0000
Subject: [PATCH 12/12] handle get_return_object_on_allocation_failure
---
clang/lib/Sema/SemaCoroutine.cpp | 55 ++++++++++---------
clang/lib/Sema/SemaDecl.cpp | 15 ++++-
.../SemaCXX/coro-return-type-and-wrapper.cpp | 12 ++++
3 files changed, 53 insertions(+), 29 deletions(-)
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index e64fb2cd8ef576..8923ce2bc7138c 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -1321,6 +1321,33 @@ static bool diagReturnOnAllocFailure(Sema &S, Expr *E,
return false;
}
+// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
+// attributes to the function `get_return_object` if its return type is marked
+// with `[[clang::coro_return_type]]` to avoid false-positive diagnostic for
+// `get_return_object`.
+static void handleGetReturnObject(Sema &S, Expr *E) {
+ if (auto *TE = dyn_cast<CXXBindTemporaryExpr>(E))
+ E = TE->getSubExpr();
+ auto *CE = cast<CallExpr>(E);
+ auto *MD = CE->getDirectCallee();
+ if (!MD)
+ return;
+ // This analysis is done only for types marked with
+ // [[clang::coro_return_type]].
+ auto *RetType = MD->getReturnType()->getAsRecordDecl();
+ if (!RetType || !RetType->hasAttr<CoroReturnTypeAttr>())
+ return;
+ // `get_return_object` should be allowed to return coro_return_type.
+ if (!MD->hasAttr<CoroWrapperAttr>())
+ MD->addAttr(
+ CoroWrapperAttr::CreateImplicit(S.getASTContext(), MD->getLocation()));
+ // Object arg of `__promise.get_return_object()` is not lifetimebound.
+ if (RetType->hasAttr<CoroLifetimeBoundAttr>() &&
+ !MD->hasAttr<CoroDisableLifetimeBoundAttr>())
+ MD->addAttr(CoroDisableLifetimeBoundAttr::CreateImplicit(
+ S.getASTContext(), MD->getLocation()));
+}
+
bool CoroutineStmtBuilder::makeReturnOnAllocFailure() {
assert(!IsPromiseDependentType &&
"cannot make statement while the promise type is dependent");
@@ -1354,6 +1381,7 @@ bool CoroutineStmtBuilder::makeReturnOnAllocFailure() {
if (ReturnObjectOnAllocationFailure.isInvalid())
return false;
+ handleGetReturnObject(S, ReturnObjectOnAllocationFailure.get());
StmtResult ReturnStmt =
S.BuildReturnStmt(Loc, ReturnObjectOnAllocationFailure.get());
if (ReturnStmt.isInvalid()) {
@@ -1797,33 +1825,6 @@ bool CoroutineStmtBuilder::makeOnException() {
return true;
}
-// Adds [[clang::coro_wrapper]] and [[clang::coro_disable_lifetimebound]]
-// attributes to the function `get_return_object` if its return type is marked
-// with `[[clang::coro_return_type]]` to avoid false-positive diagnostic for
-// `get_return_object`.
-static void handleGetReturnObject(Sema &S, Expr *E) {
- if (auto *TE = dyn_cast<CXXBindTemporaryExpr>(E))
- E = TE->getSubExpr();
- auto *CE = cast<CallExpr>(E);
- auto *MD = CE->getDirectCallee();
- if (!MD)
- return;
- // This analysis is done only for types marked with
- // [[clang::coro_return_type]].
- auto *RetType = MD->getReturnType()->getAsRecordDecl();
- if (!RetType || !RetType->hasAttr<CoroReturnTypeAttr>())
- return;
- // `get_return_object` should be allowed to return coro_return_type.
- if (!MD->hasAttr<CoroWrapperAttr>())
- MD->addAttr(
- CoroWrapperAttr::CreateImplicit(S.getASTContext(), MD->getLocation()));
- // Object arg of `__promise.get_return_object()` is not lifetimebound.
- if (RetType->hasAttr<CoroLifetimeBoundAttr>() &&
- !MD->hasAttr<CoroDisableLifetimeBoundAttr>())
- MD->addAttr(CoroDisableLifetimeBoundAttr::CreateImplicit(
- S.getASTContext(), MD->getLocation()));
-}
-
bool CoroutineStmtBuilder::makeReturnObject() {
// [dcl.fct.def.coroutine]p7
// The expression promise.get_return_object() is used to initialize the
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index efd3232261123b..db3e258e57b4e1 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -15841,6 +15841,18 @@ static void diagnoseImplicitlyRetainedSelf(Sema &S) {
<< FixItHint::CreateInsertion(P.first, "self->");
}
+static bool IsGetReturnType(FunctionDecl* FD) {
+ return isa<CXXMethodDecl>(FD) && FD->param_empty() &&
+ FD->getDeclName().isIdentifier() &&
+ FD->getName().equals("get_return_object");
+}
+
+static bool IsGetReturnTypeOnAllocFailure(FunctionDecl* FD) {
+ return FD->isStatic() && FD->param_empty() &&
+ FD->getDeclName().isIdentifier() &&
+ FD->getName().equals("get_return_object_on_allocation_failure");
+}
+
void Sema::CheckCoroutineWrapper(FunctionDecl *FD) {
RecordDecl *RD = FD->getReturnType()->getAsRecordDecl();
if (!RD || !RD->getUnderlyingDecl()->hasAttr<CoroReturnTypeAttr>())
@@ -15848,8 +15860,7 @@ void Sema::CheckCoroutineWrapper(FunctionDecl *FD) {
// Allow some_promise_type::get_return_object().
// Since we are still in the promise definition, we can only do this
// heuristically as the promise may not be yet associated to a coroutine.
- if (isa<CXXMethodDecl>(FD) && FD->getDeclName().isIdentifier() &&
- FD->getName().equals("get_return_object") && FD->param_empty())
+ if (IsGetReturnType(FD) || IsGetReturnTypeOnAllocFailure(FD))
return;
if (!FD->hasAttr<CoroWrapperAttr>())
Diag(FD->getLocation(), diag::err_coroutine_return_type) << RD;
diff --git a/clang/test/SemaCXX/coro-return-type-and-wrapper.cpp b/clang/test/SemaCXX/coro-return-type-and-wrapper.cpp
index ac49e03ba9d90a..b08e1c9c065a0e 100644
--- a/clang/test/SemaCXX/coro-return-type-and-wrapper.cpp
+++ b/clang/test/SemaCXX/coro-return-type-and-wrapper.cpp
@@ -5,11 +5,23 @@ using std::suspend_always;
using std::suspend_never;
+namespace std {
+ struct nothrow_t {};
+ constexpr nothrow_t nothrow = {};
+}
+
+using SizeT = decltype(sizeof(int));
+
+void* operator new(SizeT __sz, const std::nothrow_t&) noexcept;
+
template <typename T> struct [[clang::coro_return_type]] Gen {
struct promise_type {
Gen<T> get_return_object() {
return {};
}
+ static Gen<T> get_return_object_on_allocation_failure() {
+ return {};
+ }
suspend_always initial_suspend();
suspend_always final_suspend() noexcept;
void unhandled_exception();
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