[-Wunsafe-buffer-usage] Fix false positives in warning againt 2-parameter std::span constructor #115797
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
llvmbot
added
clang
|
@llvm/pr-subscribers-clang Author: Malavika Samak (malavikasamak) ChangesDo not warn when two parameter constructor receives pointer address from a std::addressof method and the span size is set to 1. (rdar://139298119) Full diff: https://github.com/llvm/llvm-project/pull/115797.diff 2 Files Affected:
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp
index 2c68409b846bc8..507e61564fc3f8 100644
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -410,6 +410,14 @@ AST_MATCHER(CXXConstructExpr, isSafeSpanTwoParamConstruct) {
// Check form 3:
return Arg1CV && Arg1CV->isOne();
break;
+ case Stmt::CallExprClass:
+ if(const auto *CE = dyn_cast<CallExpr>(Arg0)) {
+ const auto FnDecl = CE->getDirectCallee();
+ if(FnDecl && FnDecl->getNameAsString() == "addressof" && FnDecl->isInStdNamespace()) {
+ return Arg1CV && Arg1CV->isOne();
+ }
+ }
+ break;
default:
break;
}
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp
index c138fe088b3ba9..30b6d4ba9fb904 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp
@@ -21,6 +21,12 @@ namespace std {
template< class T >
T&& move( T&& t ) noexcept;
+
+ template <class _Tp>
+ _Tp* addressof(_Tp& __x) {
+ return &__x;
+ }
+
}
namespace irrelevant_constructors {
@@ -74,15 +80,26 @@ namespace construct_wt_ptr_size {
return std::span<int>{p, 10}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
}
+ // addressof method defined outside std namespace.
+ template <class _Tp>
+ _Tp* addressof(_Tp& __x) {
+ return &__x;
+ }
+
void notWarnSafeCases(unsigned n, int *p) {
int X;
unsigned Y = 10;
std::span<int> S = std::span{&X, 1}; // no-warning
+ S = std::span{std::addressof(X), 1}; // no-warning
int Arr[10];
typedef int TenInts_t[10];
TenInts_t Arr2;
S = std::span{&X, 2}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
+ S = std::span{std::addressof(X), 2}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
+ // Warn when a non std method also named addressof
+ S = std::span{addressof(X), 1}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
+
S = std::span{new int[10], 10}; // no-warning
S = std::span{new int[n], n}; // no-warning
S = std::span{new int, 1}; // no-warning
|
|
@llvm/pr-subscribers-clang-analysis Author: Malavika Samak (malavikasamak) ChangesDo not warn when two parameter constructor receives pointer address from a std::addressof method and the span size is set to 1. (rdar://139298119) Full diff: https://github.com/llvm/llvm-project/pull/115797.diff 2 Files Affected:
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp
index 2c68409b846bc8..507e61564fc3f8 100644
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -410,6 +410,14 @@ AST_MATCHER(CXXConstructExpr, isSafeSpanTwoParamConstruct) {
// Check form 3:
return Arg1CV && Arg1CV->isOne();
break;
+ case Stmt::CallExprClass:
+ if(const auto *CE = dyn_cast<CallExpr>(Arg0)) {
+ const auto FnDecl = CE->getDirectCallee();
+ if(FnDecl && FnDecl->getNameAsString() == "addressof" && FnDecl->isInStdNamespace()) {
+ return Arg1CV && Arg1CV->isOne();
+ }
+ }
+ break;
default:
break;
}
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp
index c138fe088b3ba9..30b6d4ba9fb904 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-in-container-span-construct.cpp
@@ -21,6 +21,12 @@ namespace std {
template< class T >
T&& move( T&& t ) noexcept;
+
+ template <class _Tp>
+ _Tp* addressof(_Tp& __x) {
+ return &__x;
+ }
+
}
namespace irrelevant_constructors {
@@ -74,15 +80,26 @@ namespace construct_wt_ptr_size {
return std::span<int>{p, 10}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
}
+ // addressof method defined outside std namespace.
+ template <class _Tp>
+ _Tp* addressof(_Tp& __x) {
+ return &__x;
+ }
+
void notWarnSafeCases(unsigned n, int *p) {
int X;
unsigned Y = 10;
std::span<int> S = std::span{&X, 1}; // no-warning
+ S = std::span{std::addressof(X), 1}; // no-warning
int Arr[10];
typedef int TenInts_t[10];
TenInts_t Arr2;
S = std::span{&X, 2}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
+ S = std::span{std::addressof(X), 2}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
+ // Warn when a non std method also named addressof
+ S = std::span{addressof(X), 1}; // expected-warning{{the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information}}
+
S = std::span{new int[10], 10}; // no-warning
S = std::span{new int[n], n}; // no-warning
S = std::span{new int, 1}; // no-warning
|
malavikasamak
requested review from
t-rasmud,
jkorous-apple and
devincoughlin
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
ziqingluo-90
approved these changes
Nov 12, 2024
There was a problem hiding this comment.
Nice!
nit: please add the pattern std::span<T>{std::addressor(...), 1} to the comment:
// Given a two-param std::span construct call, matches iff the call has the
// following forms:
// 1. `std::span<T>{new T[n], n}`, where `n` is a literal or a DRE
// 2. `std::span<T>{new T, 1}`
// 3. `std::span<T>{&var, 1}`
// 4. `std::span<T>{a, n}`, where `a` is of an array-of-T with constant size
// `n`
// 5. `std::span<T>{any, 0}`
…eter std::span constructor Do not warn when two parameter constructor receives pointer address from a std::addressof method and the span size is set to 1. (rdar://139298119)
malavikasamak
force-pushed
the
msamak-false-positive-addressof
branch
from
9b215f1 to
d0a95e1
Compare
malavikasamak
added a commit
to swiftlang/llvm-project
that referenced
this pull request
Nov 19, 2024
…eter std::span constructor (llvm#115797) Do not warn when two parameter constructor receives pointer address from a std::addressof method and the span size is set to 1. (rdar://139298119) Co-authored-by: MalavikaSamak <malavika2@apple.com> (cherry picked from commit 0dcb0ac)
malavikasamak
added a commit
to swiftlang/llvm-project
that referenced
this pull request
Nov 19, 2024
[Cherry-pick][-Wunsafe-buffer-usage] Fix false positives in warning againt 2-parameter std::span constructor (llvm#115797)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Do not warn when two parameter constructor receives pointer address from a std::addressof method and the span size is set to 1.
(rdar://139298119)