https://github.com/malavikasamak created
https://github.com/llvm/llvm-project/pull/125671
Unsafe operation in methods that are already annotated with
clang::unsafe_buffer_usage attribute, should not trigger a warning. This is
because, the developer has already identified the method as unsafe and warning
at every unsafe operation is redundant.
rdar://138644831
>From afab62e75c9130e667935d775bc256b2c3a9c62d Mon Sep 17 00:00:00 2001
From: MalavikaSamak <malavi...@apple.com>
Date: Fri, 31 Jan 2025 13:19:46 +0530
Subject: [PATCH] [Wunsafe-buffer-usage] Turn off unsafe-buffer warning for
methods annotated with clang::unsafe_buffer_usage attribute
Unsafe operation in methods that are already annotated with
clang::unsafe_buffer_usage attribute,
should not trigger a warning. This is because, the developer has already
identified
the method as unsafe and warning at every unsafe operation is redundant.
rdar://138644831
---
clang/lib/Sema/AnalysisBasedWarnings.cpp | 3 ++
...warn-unsafe-buffer-usage-function-attr.cpp | 47 ++++++++++++++++---
2 files changed, 44 insertions(+), 6 deletions(-)
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp
b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 589869d0186575b..7111dfd523a1014 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -2610,6 +2610,9 @@ void clang::sema::AnalysisBasedWarnings::IssueWarnings(
// The Callback function that performs analyses:
auto CallAnalyzers = [&](const Decl *Node) -> void {
+ if (isa<FunctionDecl>(Node) && Node->hasAttr<UnsafeBufferUsageAttr>())
+ return;
+
// Perform unsafe buffer usage analysis:
if (!Diags.isIgnored(diag::warn_unsafe_buffer_operation,
Node->getBeginLoc()) ||
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
b/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
index 724d444638b57e7..ef724acc761dbd1 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
@@ -119,16 +119,15 @@ struct HoldsUnsafeMembers {
[[clang::unsafe_buffer_usage]]
HoldsUnsafeMembers(int i)
- : FromCtor(i), // expected-warning{{function introduces unsafe buffer
manipulation}}
- FromCtor2{i} // expected-warning{{function introduces unsafe buffer
manipulation}}
- {}
+ : FromCtor(i),
+ FromCtor2{i} {}
HoldsUnsafeMembers(float f)
: HoldsUnsafeMembers(0) {} // expected-warning{{function introduces
unsafe buffer manipulation}}
UnsafeMembers FromCtor;
UnsafeMembers FromCtor2;
- UnsafeMembers FromField{3}; // expected-warning 2{{function introduces
unsafe buffer manipulation}}
+ UnsafeMembers FromField{3}; // expected-warning {{function introduces
unsafe buffer manipulation}}
};
struct SubclassUnsafeMembers : public UnsafeMembers {
@@ -138,8 +137,7 @@ struct SubclassUnsafeMembers : public UnsafeMembers {
[[clang::unsafe_buffer_usage]]
SubclassUnsafeMembers(int i)
- : UnsafeMembers(i) // expected-warning{{function introduces unsafe
buffer manipulation}}
- {}
+ : UnsafeMembers(i){}
};
// https://github.com/llvm/llvm-project/issues/80482
@@ -245,3 +243,40 @@ struct AggregateViaDefaultInit {
void testAggregateViaDefaultInit() {
AggregateViaDefaultInit A;
};
+
+struct A {
+ int arr[2];
+
+ [[clang::unsafe_buffer_usage]]
+ int *ptr;
+};
+
+namespace std{
+ template <typename T> class span {
+
+ T *elements;
+
+ public:
+
+ constexpr span(T *, unsigned){}
+
+ template<class Begin, class End>
+ constexpr span(Begin first, End last){}
+
+ constexpr T* data() const noexcept {
+ return elements;
+ }
+ };
+}
+
+[[clang::unsafe_buffer_usage]]
+void check_no_warnings(unsigned idx) {
+ int *arr = new int[20];
+
+ int k = arr[idx]; // no-warning
+
+ std::span<int> sp = {arr, 20}; // no-warning
+ A *ptr = reinterpret_cast<A*> (sp.data()); // no-warning
+ A a;
+ a.ptr = arr; // no-warning
+}
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