https://github.com/hokein updated
https://github.com/llvm/llvm-project/pull/118078
>From 4db8f43507d6d36ef1cfeabb4c308e781a1b061e Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein...@gmail.com>
Date: Fri, 29 Nov 2024 11:07:56 +0100
Subject: [PATCH 1/2] [clang] Infer lifetime_capture_by for map's subscript
operator.
---
clang/lib/Sema/SemaAttr.cpp | 59 +++++++++++++--------
clang/test/AST/attr-lifetime-capture-by.cpp | 16 ++++++
2 files changed, 53 insertions(+), 22 deletions(-)
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index d3cf42251be2e7..3279f4109a9c02 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -270,34 +270,49 @@ void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
}
void Sema::inferLifetimeCaptureByAttribute(FunctionDecl *FD) {
- if (!FD)
+ auto *MD = dyn_cast_if_present<CXXMethodDecl>(FD);
+ if (!MD || !MD->getParent()->isInStdNamespace())
return;
- auto *MD = dyn_cast<CXXMethodDecl>(FD);
- if (!MD || !MD->getIdentifier() || !MD->getParent()->isInStdNamespace())
+ auto Annotate = [this](const FunctionDecl *MD) {
+ // Do not infer if any parameter is explicitly annotated.
+ for (ParmVarDecl *PVD : MD->parameters())
+ if (PVD->hasAttr<LifetimeCaptureByAttr>())
+ return;
+ for (ParmVarDecl *PVD : MD->parameters()) {
+ // Methods in standard containers that capture values typically accept
+ // reference-type parameters, e.g., `void push_back(const T& value)`.
+ // We only apply the lifetime_capture_by attribute to parameters of
+ // pointer-like reference types (`const T&`, `T&&`).
+ if (PVD->getType()->isReferenceType() &&
+ sema::isPointerLikeType(PVD->getType().getNonReferenceType())) {
+ int CaptureByThis[] = {LifetimeCaptureByAttr::THIS};
+ PVD->addAttr(
+ LifetimeCaptureByAttr::CreateImplicit(Context, CaptureByThis, 1));
+ }
+ }
+ };
+
+ if (!MD->getIdentifier()) {
+ static const llvm::StringSet<> MapLikeContainer{
+ "map",
+ "multimap",
+ "unordered_map",
+ "unordered_multimap",
+ };
+ // Infer for the map's operator []:
+ // std::map<string_view, ...> m;
+ // m[ReturnString(..)] = ...; // !dangling references in m.
+ if (MD->getOverloadedOperator() != OO_Subscript ||
+ !MapLikeContainer.contains(MD->getParent()->getName()))
+ return;
+ Annotate(MD);
return;
- // FIXME: Infer for operator[] for map-like containers. For example:
- // std::map<string_view, ...> m;
- // m[ReturnString(..)] = ...;
+ }
static const llvm::StringSet<> CapturingMethods{"insert", "push",
"push_front", "push_back"};
if (!CapturingMethods.contains(MD->getName()))
return;
- // Do not infer if any parameter is explicitly annotated.
- for (ParmVarDecl *PVD : MD->parameters())
- if (PVD->hasAttr<LifetimeCaptureByAttr>())
- return;
- for (ParmVarDecl *PVD : MD->parameters()) {
- // Methods in standard containers that capture values typically accept
- // reference-type parameters, e.g., `void push_back(const T& value)`.
- // We only apply the lifetime_capture_by attribute to parameters of
- // pointer-like reference types (`const T&`, `T&&`).
- if (PVD->getType()->isReferenceType() &&
- sema::isPointerLikeType(PVD->getType().getNonReferenceType())) {
- int CaptureByThis[] = {LifetimeCaptureByAttr::THIS};
- PVD->addAttr(
- LifetimeCaptureByAttr::CreateImplicit(Context, CaptureByThis, 1));
- }
- }
+ Annotate(MD);
}
void Sema::inferNullableClassAttribute(CXXRecordDecl *CRD) {
diff --git a/clang/test/AST/attr-lifetime-capture-by.cpp
b/clang/test/AST/attr-lifetime-capture-by.cpp
index debad9b7204d72..71b348dac764bc 100644
--- a/clang/test/AST/attr-lifetime-capture-by.cpp
+++ b/clang/test/AST/attr-lifetime-capture-by.cpp
@@ -30,6 +30,12 @@ struct vector {
void insert(iterator, T&&);
};
+
+template <typename Key, typename Value>
+struct map {
+ Value& operator[](Key&& p);
+ Value& operator[](const Key& p);
+};
} // namespace std
// CHECK-NOT: LifetimeCaptureByAttr
@@ -99,3 +105,13 @@ std::vector<int> ints;
// CHECK-NEXT: ParmVarDecl {{.*}} 'iterator'
// CHECK-NEXT: ParmVarDecl {{.*}} 'int &&'
// CHECK-NOT: LifetimeCaptureByAttr
+
+std::map<View, int> map;
+// CHECK: ClassTemplateSpecializationDecl {{.*}} struct map definition
implicit_instantiation
+
+// CHECK: CXXMethodDecl {{.*}} operator[] 'int &(View &&)'
implicit_instantiation
+// CHECK-NEXT: ParmVarDecl {{.*}} p 'View &&'
+// CHECK-NEXT: LifetimeCaptureByAttr {{.*}} Implicit
+// CHECK: CXXMethodDecl {{.*}} operator[] 'int &(const View &)'
implicit_instantiation
+// CHECK-NEXT: ParmVarDecl {{.*}} p 'const View &'
+// CHECK-NEXT: LifetimeCaptureByAttr {{.*}} Implicit
>From ce01d4b7566ce7d0a098155a71ac8b8ae40a7a7b Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein...@gmail.com>
Date: Mon, 2 Dec 2024 09:24:41 +0100
Subject: [PATCH 2/2] Address review comment.
---
clang/lib/Sema/SemaAttr.cpp | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 3279f4109a9c02..479f47962a7c3d 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -302,10 +302,9 @@ void Sema::inferLifetimeCaptureByAttribute(FunctionDecl
*FD) {
// Infer for the map's operator []:
// std::map<string_view, ...> m;
// m[ReturnString(..)] = ...; // !dangling references in m.
- if (MD->getOverloadedOperator() != OO_Subscript ||
- !MapLikeContainer.contains(MD->getParent()->getName()))
- return;
- Annotate(MD);
+ if (MD->getOverloadedOperator() == OO_Subscript &&
+ MapLikeContainer.contains(MD->getParent()->getName()))
+ Annotate(MD);
return;
}
static const llvm::StringSet<> CapturingMethods{"insert", "push",
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