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Immediate invocations do not need to run cleanups themselves and the
destructors need to run after each full-expression is processed.
Attempting to add ExprWithCleanups for each immediate invocation may cause
adding it in the wrong place and producing code with memory leaks.
Thanks @ilya-biryukov for helping reducing the reproducer and confirming
that the analysis is correct.
Fixes https://github.com/llvm/llvm-project/issues/60709
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D153294
Files:
clang/docs/ReleaseNotes.rst
clang/lib/Sema/SemaExpr.cpp
clang/test/CodeGenCXX/consteval-cleanup.cpp
clang/test/SemaCXX/consteval-cleanup.cpp
Index: clang/test/SemaCXX/consteval-cleanup.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/consteval-cleanup.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -Wno-unused-value -std=c++20 -ast-dump -verify %s -ast-dump
| FileCheck %s
+
+// expected-no-diagnostics
+
+struct P {
+ consteval P() {}
+};
+
+struct A {
+ A(int v) { this->data = new int(v); }
+ ~A() { delete data; }
+private:
+ int *data;
+};
+
+void foo() {
+ for (;A(1), P(), false;);
+ // CHECK: foo
+ // CHECK: ExprWithCleanups
+ // CHECK-NEXT: BinaryOperator
+ // CHECK: ConstantExpr
+ // CHECK-NOT: ExprWithCleanups
+}
+
+struct B {
+ int *p = new int(38);
+ consteval int get() { return *p; }
+ constexpr ~B() { delete p; }
+};
+
+void bar() {
+ // CHECK: bar
+ // CHECK: ExprWithCleanups
+ // CHECK-NEXT: ConstantExpr
+ int k = B().get();
+}
Index: clang/test/CodeGenCXX/consteval-cleanup.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/consteval-cleanup.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -std=c++20 -Wno-unused-value -triple x86_64-linux-gnu
-emit-llvm %s -o - | FileCheck %s
+
+struct P {
+ consteval P() {}
+};
+
+struct A {
+ A(int v) { this->data = new int(v); }
+ ~A() { delete data; }
+private:
+ int *data;
+};
+
+void foo() {
+ for (;A(1), P(), false;);
+ // CHECK: foo
+ // CHECK: for.cond:
+ // CHECK: call void @_ZN1AC1Ei
+ // CHECK: call void @_ZN1AD1Ev
+ // CHECK: for.body
+}
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -18170,8 +18170,6 @@
return E;
}
- E = MaybeCreateExprWithCleanups(E);
-
ConstantExpr *Res = ConstantExpr::Create(
getASTContext(), E.get(),
ConstantExpr::getStorageKind(Decl->getReturnType().getTypePtr(),
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -520,6 +520,10 @@
type by the default argument promotions, and thus this is UB. Clang's
behavior now matches GCC's behavior in C++.
(`#38717 <https://github.com/llvm/llvm-project/issues/38717>_`).
+- Fix missing destructor calls and therefore memory leaks in generated code
+ when an immediate invocation appears as a part of an expression that produces
+ temporaries.
+ (`#60709 <https://github.com/llvm/llvm-project/issues/60709>_`).
Bug Fixes to Compiler Builtins
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Index: clang/test/SemaCXX/consteval-cleanup.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/consteval-cleanup.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -Wno-unused-value -std=c++20 -ast-dump -verify %s -ast-dump | FileCheck %s
+
+// expected-no-diagnostics
+
+struct P {
+ consteval P() {}
+};
+
+struct A {
+ A(int v) { this->data = new int(v); }
+ ~A() { delete data; }
+private:
+ int *data;
+};
+
+void foo() {
+ for (;A(1), P(), false;);
+ // CHECK: foo
+ // CHECK: ExprWithCleanups
+ // CHECK-NEXT: BinaryOperator
+ // CHECK: ConstantExpr
+ // CHECK-NOT: ExprWithCleanups
+}
+
+struct B {
+ int *p = new int(38);
+ consteval int get() { return *p; }
+ constexpr ~B() { delete p; }
+};
+
+void bar() {
+ // CHECK: bar
+ // CHECK: ExprWithCleanups
+ // CHECK-NEXT: ConstantExpr
+ int k = B().get();
+}
Index: clang/test/CodeGenCXX/consteval-cleanup.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/consteval-cleanup.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -std=c++20 -Wno-unused-value -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck %s
+
+struct P {
+ consteval P() {}
+};
+
+struct A {
+ A(int v) { this->data = new int(v); }
+ ~A() { delete data; }
+private:
+ int *data;
+};
+
+void foo() {
+ for (;A(1), P(), false;);
+ // CHECK: foo
+ // CHECK: for.cond:
+ // CHECK: call void @_ZN1AC1Ei
+ // CHECK: call void @_ZN1AD1Ev
+ // CHECK: for.body
+}
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -18170,8 +18170,6 @@
return E;
}
- E = MaybeCreateExprWithCleanups(E);
-
ConstantExpr *Res = ConstantExpr::Create(
getASTContext(), E.get(),
ConstantExpr::getStorageKind(Decl->getReturnType().getTypePtr(),
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -520,6 +520,10 @@
type by the default argument promotions, and thus this is UB. Clang's
behavior now matches GCC's behavior in C++.
(`#38717 <https://github.com/llvm/llvm-project/issues/38717>_`).
+- Fix missing destructor calls and therefore memory leaks in generated code
+ when an immediate invocation appears as a part of an expression that produces
+ temporaries.
+ (`#60709 <https://github.com/llvm/llvm-project/issues/60709>_`).
Bug Fixes to Compiler Builtins
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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