[clang] [-Wunsafe-buffer-usage] Fixits for unsafe arguments of function pointer calls (PR #80358)
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Tue Feb 13 14:34:38 PST 2024
https://github.com/jkorous-apple updated https://github.com/llvm/llvm-project/pull/80358
>From 0679f7aef924b9c81e9632f75d9a29b3e469fb33 Mon Sep 17 00:00:00 2001
From: Jan Korous <jkorous at apple.com>
Date: Thu, 25 Jan 2024 13:52:12 -0800
Subject: [PATCH 1/3] [-Wunsafe-buffer-usage] Emit fixits for arguments of
function pointers calls
Currently we ignore calls on function pointers (unlike direct calls of
functions and class methods). This patch adds support for function pointers as
well.
The change is to simply replace use of forEachArgumentWithParam matcher in UPC
gadget with forEachArgumentWithParamType.
from the documentation of forEachArgumentWithParamType:
/// Matches all arguments and their respective types for a \c CallExpr or
/// \c CXXConstructExpr. It is very similar to \c forEachArgumentWithParam but
/// it works on calls through function pointers as well.
---
clang/lib/Analysis/UnsafeBufferUsage.cpp | 4 ++--
...fer-usage-fixits-pointer-arg-to-func-ptr-call.cpp | 12 ++++++++++++
2 files changed, 14 insertions(+), 2 deletions(-)
create mode 100644 clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp
index d00c598c4b9de3..c5a87f14bc8880 100644
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -282,8 +282,8 @@ isInUnspecifiedPointerContext(internal::Matcher<Stmt> InnerMatcher) {
// (i.e., computing the distance between two pointers); or ...
auto CallArgMatcher =
- callExpr(forEachArgumentWithParam(InnerMatcher,
- hasPointerType() /* array also decays to pointer type*/),
+ callExpr(forEachArgumentWithParamType(InnerMatcher,
+ isAnyPointer() /* array also decays to pointer type*/),
unless(callee(functionDecl(hasAttr(attr::UnsafeBufferUsage)))));
auto CastOperandMatcher =
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp
new file mode 100644
index 00000000000000..ae761e46a98191
--- /dev/null
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -std=c++20 -Wunsafe-buffer-usage \
+// RUN: -fsafe-buffer-usage-suggestions \
+// RUN: -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+void unsafe_array_func_ptr_call(void (*fn_ptr)(int *param)) {
+ int p[32];
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:12}:"std::array<int, 32> p"
+
+ int tmp = p[5];
+ fn_ptr(p);
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:11}:".data()"
+}
>From 8cfe24aede15d479e3053dcf2e960a6a3e046744 Mon Sep 17 00:00:00 2001
From: Jan Korous <jkorous at apple.com>
Date: Thu, 1 Feb 2024 14:44:01 -0800
Subject: [PATCH 2/3] [-Wunsafe-buffer-usage][NFC] Add tests for function
pointer call fixits
---
...ge-fixits-pointer-arg-to-func-ptr-call.cpp | 38 ++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp
index ae761e46a98191..0459d6549fd86f 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp
@@ -6,7 +6,43 @@ void unsafe_array_func_ptr_call(void (*fn_ptr)(int *param)) {
int p[32];
// CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:12}:"std::array<int, 32> p"
- int tmp = p[5];
+ p[5] = 10;
fn_ptr(p);
// CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:11}:".data()"
}
+
+void unsafe_ptr_func_ptr_call(void (*fn_ptr)(int *param)) {
+ int *p;
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:9}:"std::span<int> p"
+
+ p[5] = 10;
+ fn_ptr(p);
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:11}:".data()"
+}
+
+void addr_of_unsafe_ptr_func_ptr_call(void (*fn_ptr)(int *param)) {
+ int *p;
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:9}:"std::span<int> p"
+
+ p[5] = 10;
+ fn_ptr(&p[0]);
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:10-[[@LINE-1]]:15}:"p.data()"
+}
+
+void addr_of_unsafe_ptr_w_offset_func_ptr_call(void (*fn_ptr)(int *param)) {
+ int *p;
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:9}:"std::span<int> p"
+
+ p[5] = 10;
+ fn_ptr(&p[3]);
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:10-[[@LINE-1]]:15}:"&p.data()[3]"
+}
+
+void preincrement_unsafe_ptr_func_ptr_call(void (*fn_ptr)(int *param)) {
+ int *p;
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:9}:"std::span<int> p"
+
+ p[5] = 10;
+ fn_ptr(++p);
+ // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:10-[[@LINE-1]]:13}:"(p = p.subspan(1)).data()"
+}
>From d95caebd703544aeca6d7c0fbc38a8bbfb965b70 Mon Sep 17 00:00:00 2001
From: Jan Korous <jkorous at apple.com>
Date: Tue, 13 Feb 2024 14:24:45 -0800
Subject: [PATCH 3/3] [-Wunsafe-buffer-usage][NFC] Format AST matcher in
isInUnspecifiedPointerContext
...and turn off clang-format for the block of AST matchers.
---
clang/lib/Analysis/UnsafeBufferUsage.cpp | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp
index c5a87f14bc8880..c07517190bbcec 100644
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -281,10 +281,14 @@ isInUnspecifiedPointerContext(internal::Matcher<Stmt> InnerMatcher) {
// 4. the operand of a pointer subtraction operation
// (i.e., computing the distance between two pointers); or ...
+ // clang-format off
auto CallArgMatcher =
- callExpr(forEachArgumentWithParamType(InnerMatcher,
- isAnyPointer() /* array also decays to pointer type*/),
- unless(callee(functionDecl(hasAttr(attr::UnsafeBufferUsage)))));
+ callExpr(
+ forEachArgumentWithParam(
+ InnerMatcher,
+ hasPointerType() /* array also decays to pointer type*/),
+ unless(callee(
+ functionDecl(hasAttr(attr::UnsafeBufferUsage)))));
auto CastOperandMatcher =
castExpr(anyOf(hasCastKind(CastKind::CK_PointerToIntegral),
@@ -306,6 +310,7 @@ isInUnspecifiedPointerContext(internal::Matcher<Stmt> InnerMatcher) {
hasRHS(hasPointerType())),
eachOf(hasLHS(InnerMatcher),
hasRHS(InnerMatcher)));
+ // clang-format on
return stmt(anyOf(CallArgMatcher, CastOperandMatcher, CompOperandMatcher,
PtrSubtractionMatcher));
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