https://github.com/malavikasamak updated
https://github.com/llvm/llvm-project/pull/118249
>From a3bc09e9ad3e12a2041eb41671872781638b7aa9 Mon Sep 17 00:00:00 2001
From: MalavikaSamak <malavi...@apple.com>
Date: Fri, 29 Nov 2024 14:53:37 +0530
Subject: [PATCH] [-Wunsafe-buffer-usage] Suppress warning for
multi-dimensional constant arrays
Do not warn about unsafe buffer access, when multi-dimensional constant arrays
are accessed and their indices are within the bounds of the buffer. Warning in
such cases would be a false positive. Such a suppression already exists for 1-d
arrays and it is now extended to multi-dimensional arrays.
(rdar://137926311)
---
clang/lib/Analysis/UnsafeBufferUsage.cpp | 58 ++++++++++---------
.../warn-unsafe-buffer-usage-array.cpp | 6 ++
.../warn-unsafe-buffer-usage-field-attr.cpp | 1 -
...n-unsafe-buffer-usage-fixits-parm-main.cpp | 3 +-
...e-buffer-usage-fixits-parm-unsupported.cpp | 2 +-
.../test/SemaCXX/warn-unsafe-buffer-usage.cpp | 54 +++++++----------
6 files changed, 60 insertions(+), 64 deletions(-)
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp
b/clang/lib/Analysis/UnsafeBufferUsage.cpp
index 5f36ffa926b269..d3aab0ccd589d6 100644
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -433,37 +433,35 @@ AST_MATCHER(ArraySubscriptExpr, isSafeArraySubscript) {
// already duplicated
// - call both from Sema and from here
- const auto *BaseDRE =
- dyn_cast<DeclRefExpr>(Node.getBase()->IgnoreParenImpCasts());
- const auto *SLiteral =
- dyn_cast<StringLiteral>(Node.getBase()->IgnoreParenImpCasts());
- uint64_t size;
-
- if (!BaseDRE && !SLiteral)
- return false;
-
- if (BaseDRE) {
- if (!BaseDRE->getDecl())
- return false;
- const auto *CATy = Finder->getASTContext().getAsConstantArrayType(
- BaseDRE->getDecl()->getType());
- if (!CATy) {
+ std::function<bool(const ArraySubscriptExpr *)> CheckBounds =
+ [&CheckBounds](const ArraySubscriptExpr *ASE) -> bool {
+ uint64_t limit;
+ if (const auto *CATy =
+ dyn_cast<ConstantArrayType>(ASE->getBase()
+ ->IgnoreParenImpCasts()
+ ->getType()
+ ->getUnqualifiedDesugaredType())) {
+ limit = CATy->getLimitedSize();
+ } else if (const auto *SLiteral = dyn_cast<StringLiteral>(
+ ASE->getBase()->IgnoreParenImpCasts())) {
+ limit = SLiteral->getLength() + 1;
+ } else
return false;
- }
- size = CATy->getLimitedSize();
- } else if (SLiteral) {
- size = SLiteral->getLength() + 1;
- }
- if (const auto *IdxLit = dyn_cast<IntegerLiteral>(Node.getIdx())) {
- const APInt ArrIdx = IdxLit->getValue();
- // FIXME: ArrIdx.isNegative() we could immediately emit an error as that's
a
- // bug
- if (ArrIdx.isNonNegative() && ArrIdx.getLimitedValue() < size)
+ if (const auto *IdxLit = dyn_cast<IntegerLiteral>(ASE->getIdx())) {
+ const APInt ArrIdx = IdxLit->getValue();
+ if (!ArrIdx.isNonNegative() || ArrIdx.getLimitedValue() >= limit)
+ return false;
+ if (const auto *BaseASE = dyn_cast<ArraySubscriptExpr>(
+ ASE->getBase()->IgnoreParenImpCasts())) {
+ return CheckBounds(BaseASE);
+ }
return true;
- }
+ }
+ return false;
+ };
- return false;
+ return CheckBounds(&Node);
}
AST_MATCHER_P(CallExpr, hasNumArgs, unsigned, Num) {
@@ -1172,6 +1170,12 @@ class ArraySubscriptGadget : public WarningGadget {
if (const auto *DRE =
dyn_cast<DeclRefExpr>(ASE->getBase()->IgnoreParenImpCasts())) {
return {DRE};
+ } else if (const auto *BaseASE = dyn_cast<ArraySubscriptExpr>(
+ ASE->getBase()->IgnoreParenImpCasts())) {
+ if (const auto *DRE = dyn_cast<DeclRefExpr>(
+ BaseASE->getBase()->IgnoreParenImpCasts())) {
+ return {DRE};
+ }
}
return {};
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp
b/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp
index c6c93a27e4b969..41cdc122b7d2fa 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp
@@ -52,3 +52,9 @@ void constant_id_string(unsigned idx) {
unsafe_char = ""[1]; //expected-warning{{unsafe buffer access}}
unsafe_char = ""[idx]; //expected-warning{{unsafe buffer access}}
}
+
+typedef float Float4x4[4][4];
+
+float multi_dimension_array(Float4x4& matrix) {
+ return matrix[1][1];
+}
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-field-attr.cpp
b/clang/test/SemaCXX/warn-unsafe-buffer-usage-field-attr.cpp
index 0ba605475925b9..1636c948da075a 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-field-attr.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-field-attr.cpp
@@ -96,7 +96,6 @@ void test_attribute_multiple_fields (D d) {
int v = d.buf[0]; //expected-warning{{field 'buf' prone to unsafe buffer
manipulation}}
- //expected-warning@+1{{unsafe buffer access}}
v = d.buf[5]; //expected-warning{{field 'buf' prone to unsafe buffer
manipulation}}
}
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-main.cpp
b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-main.cpp
index c6b095031e0e32..d1fd1c00a9ea34 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-main.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-main.cpp
@@ -8,6 +8,5 @@
// main function
int main(int argc, char *argv[]) { // expected-warning{{'argv' is an unsafe
pointer used for buffer access}}
char tmp;
- tmp = argv[5][5]; // expected-note{{used in buffer access
here}} \
- expected-warning{{unsafe buffer access}}
+ tmp = argv[5][5]; // expected-note2{{used in buffer access
here}}
}
diff --git
a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-unsupported.cpp
b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-unsupported.cpp
index 71350098613d19..5b22a5c5f8acfb 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-unsupported.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-parm-unsupported.cpp
@@ -118,7 +118,7 @@ void isArrayDecayToPointerUPC(int a[][10], int (*b)[10]) {
// expected-warning@-2{{'b' is an unsafe pointer used for buffer access}}
int tmp;
- tmp = a[5][5] + b[5][5]; // expected-warning2{{unsafe buffer access}}
expected-note2{{used in buffer access here}}
+ tmp = a[5][5] + b[5][5]; // expected-note4{{used in buffer access here}}
}
// parameter having default values:
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp
b/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp
index 642db0e9d3c632..d2bdd3762a65ad 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp
@@ -40,12 +40,9 @@ void testArraySubscripts(int idx, int *p, int **pp) {
// expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
// expected-warning@-2{{'pp' is an unsafe pointer used for buffer access}}
foo(p[1], // expected-note{{used in buffer access here}}
- pp[1][1], // expected-note{{used in buffer access here}}
- // expected-warning@-1{{unsafe buffer access}}
- 1[1[pp]], // expected-note{{used in buffer access here}}
- // expected-warning@-1{{unsafe buffer access}}
- 1[pp][1] // expected-note{{used in buffer access here}}
- // expected-warning@-1{{unsafe buffer access}}
+ pp[1][1], // expected-note2{{used in buffer access here}}
+ 1[1[pp]], // expected-note2{{used in buffer access here}}
+ 1[pp][1] // expected-note2{{used in buffer access here}}
);
if (p[3]) { // expected-note{{used in buffer access here}}
@@ -65,13 +62,9 @@ void testArraySubscripts(int idx, int *p, int **pp) {
int b[10][10]; // expected-warning{{'b' is an unsafe buffer that does
not perform bounds checks}}
foo(a[idx], idx[a], // expected-note2{{used in buffer access here}}
- b[idx][idx + 1], // expected-warning{{unsafe buffer access}}
- // expected-note@-1{{used in buffer access here}}
- (idx + 1)[b][idx],// expected-warning{{unsafe buffer access}}
- // expected-note@-1{{used in buffer access here}}
- (idx + 1)[idx[b]]);
- // expected-warning@-1{{unsafe buffer access}}
- // expected-note@-2{{used in buffer access here}}
+ b[idx][idx + 1], // expected-note2{{used in buffer access here}}
+ (idx + 1)[b][idx],// expected-note2{{used in buffer access here}}
+ (idx + 1)[idx[b]]); // expected-note2{{used in buffer access here}}
// Not to warn when index is zero
foo(p[0], pp[0][0], 0[0[pp]], 0[pp][0],
@@ -108,8 +101,7 @@ void testQualifiedParameters(const int * p, const int *
const q, const int a[10]
foo(p[1], 1[p], p[-1], // expected-note3{{used in buffer access here}}
q[1], 1[q], q[-1], // expected-note3{{used in buffer access here}}
a[1], // expected-note{{used in buffer access here}}
`a` is of pointer type
- b[1][2] // expected-note{{used in buffer access here}}
`b[1]` is of array type
- // expected-warning@-1{{unsafe buffer access}}
+ b[1][2] // expected-note2{{used in buffer access here}}
`b[1]` is of array type
);
}
@@ -128,25 +120,25 @@ T_t funRetT();
T_t * funRetTStar();
void testStructMembers(struct T * sp, struct T s, T_t * sp2, T_t s2) {
- foo(sp->a[1], // expected-warning{{unsafe buffer access}}
+ foo(sp->a[1],
sp->b[1], // expected-warning{{unsafe buffer access}}
- sp->c.a[1], // expected-warning{{unsafe buffer access}}
+ sp->c.a[1],
sp->c.b[1], // expected-warning{{unsafe buffer access}}
- s.a[1], // expected-warning{{unsafe buffer access}}
+ s.a[1],
s.b[1], // expected-warning{{unsafe buffer access}}
- s.c.a[1], // expected-warning{{unsafe buffer access}}
+ s.c.a[1],
s.c.b[1], // expected-warning{{unsafe buffer access}}
- sp2->a[1], // expected-warning{{unsafe buffer access}}
+ sp2->a[1],
sp2->b[1], // expected-warning{{unsafe buffer access}}
- sp2->c.a[1], // expected-warning{{unsafe buffer access}}
+ sp2->c.a[1],
sp2->c.b[1], // expected-warning{{unsafe buffer access}}
- s2.a[1], // expected-warning{{unsafe buffer access}}
+ s2.a[1],
s2.b[1], // expected-warning{{unsafe buffer access}}
- s2.c.a[1], // expected-warning{{unsafe buffer access}}
+ s2.c.a[1],
s2.c.b[1], // expected-warning{{unsafe buffer access}}
- funRetT().a[1], // expected-warning{{unsafe buffer access}}
+ funRetT().a[1],
funRetT().b[1], // expected-warning{{unsafe buffer access}}
- funRetTStar()->a[1], // expected-warning{{unsafe buffer access}}
+ funRetTStar()->a[1],
funRetTStar()->b[1] // expected-warning{{unsafe buffer access}}
);
}
@@ -213,7 +205,6 @@ void testTypedefs(T_ptr_t p) {
// expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
foo(p[1], // expected-note{{used in buffer access here}}
p[1].a[1], // expected-note{{used in buffer access here}}
- // expected-warning@-1{{unsafe buffer access}}
p[1].b[1] // expected-note{{used in buffer access here}}
// expected-warning@-1{{unsafe buffer access}}
);
@@ -223,10 +214,9 @@ template<typename T, int N> T f(T t, T * pt, T a[N], T
(&b)[N]) {
// expected-warning@-1{{'t' is an unsafe pointer used for buffer access}}
// expected-warning@-2{{'pt' is an unsafe pointer used for buffer access}}
// expected-warning@-3{{'a' is an unsafe pointer used for buffer access}}
- // expected-warning@-4{{'b' is an unsafe buffer that does not perform bounds
checks}}
foo(pt[1], // expected-note{{used in buffer access here}}
a[1], // expected-note{{used in buffer access here}}
- b[1]); // expected-note{{used in buffer access here}}
+ b[1]);
return &t[1]; // expected-note{{used in buffer access here}}
}
@@ -366,17 +356,15 @@ int testArrayAccesses(int n, int idx) {
// expected-warning@-1{{'cArr' is an unsafe buffer that does not perform
bounds checks}}
int d = cArr[0][0];
foo(cArr[0][0]);
- foo(cArr[idx][idx + 1]); // expected-note{{used in buffer access
here}}
- // expected-warning@-1{{unsafe buffer
access}}
- auto cPtr = cArr[idx][idx * 2]; // expected-note{{used in buffer access
here}}
- // expected-warning@-1{{unsafe buffer
access}}
+ foo(cArr[idx][idx + 1]); // expected-note2{{used in buffer access
here}}
+ auto cPtr = cArr[idx][idx * 2]; // expected-note2{{used in buffer access
here}}
foo(cPtr);
// Typdefs
typedef int A[3];
const A tArr = {4, 5, 6};
foo(tArr[0], tArr[1]);
- return cArr[0][1]; // expected-warning{{unsafe buffer access}}
+ return cArr[0][1];
}
void testArrayPtrArithmetic(int x[]) { // expected-warning{{'x' is an unsafe
pointer used for buffer access}}
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
