https://github.com/malavikasamak updated
https://github.com/llvm/llvm-project/pull/125671
>From 821a4b46705375bb34e207d406d8d7e9a2818f85 Mon Sep 17 00:00:00 2001
From: MalavikaSamak <malavi...@apple.com>
Date: Fri, 31 Jan 2025 13:19:46 +0530
Subject: [PATCH 1/3] [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/docs/ReleaseNotes.rst | 2 +
clang/lib/Sema/AnalysisBasedWarnings.cpp | 3 ++
...warn-unsafe-buffer-usage-function-attr.cpp | 47 ++++++++++++++++---
3 files changed, 46 insertions(+), 6 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 30364a747f9c1..b4d2ba043bfb5 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -109,6 +109,8 @@ Removed Compiler Flags
Attribute Changes in Clang
--------------------------
+Adding [[clang::unsafe_buffer_usage]] attribute to a method definition now
turns off all -Wunsafe-buffer-usage
+related warnings within the method body.
Improvements to Clang's diagnostics
-----------------------------------
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp
b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 589869d018657..ef87efc9b9942 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 (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 724d444638b57..ef724acc761db 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
+}
>From b37f48fb71100821a7be3e00c57418603f26935e Mon Sep 17 00:00:00 2001
From: MalavikaSamak <malavi...@apple.com>
Date: Fri, 21 Feb 2025 11:09:10 -0800
Subject: [PATCH 2/3] Add additional tests to check suppression in variadic
functions and their callers.
---
.../warn-unsafe-buffer-usage-function-attr.cpp | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
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 ef724acc761db..4318df930eb59 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
@@ -280,3 +280,19 @@ void check_no_warnings(unsigned idx) {
A a;
a.ptr = arr; // no-warning
}
+
+[[clang::unsafe_buffer_usage]]
+void check_no_warning_variadic(unsigned idx, int arr[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
+}
+
+void invoke_methods() {
+ int array[20];
+ check_no_warnings(30); //expected-warning{{function introduces unsafe buffer
manipulation}}
+ check_no_warning_variadic(20, array); //expected-warning{{function
introduces unsafe buffer manipulation}}
+}
>From e918986a7760342d41df3f1e6eb12c9e7f8431ab Mon Sep 17 00:00:00 2001
From: MalavikaSamak <malavi...@apple.com>
Date: Mon, 24 Feb 2025 10:04:24 -0800
Subject: [PATCH 3/3] Adding a test to check behavior with templated methods.
---
.../warn-unsafe-buffer-usage-function-attr.cpp | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
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 4318df930eb59..f3abe87928400 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
@@ -291,8 +291,20 @@ void check_no_warning_variadic(unsigned idx, int arr[20],
...) {
a.ptr = arr; // no-warning
}
+template<typename T>
+[[clang::unsafe_buffer_usage]]
+void check_no_warnings_template(unsigned idx, T* arr) {
+ 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
+}
+
void invoke_methods() {
int array[20];
check_no_warnings(30); //expected-warning{{function introduces unsafe buffer
manipulation}}
- check_no_warning_variadic(20, array); //expected-warning{{function
introduces unsafe buffer manipulation}}
+ check_no_warning_variadic(15, array); //expected-warning{{function
introduces unsafe buffer manipulation}}
+ check_no_warnings_template(10, array); //expected-warning{{function
introduces unsafe buffer manipulation}}
}
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