[-Wunsafe-buffer-usage] Suppress warning for multi-dimensional constant arrays (#118249)

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)
(rdar://140320139)

Co-authored-by: MalavikaSamak <malavika2@apple.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp
index c6c93a2..7dd6c83 100644
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp
@@ -52,3 +52,43 @@ 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];
+
+// expected-warning@+1 {{'matrix' is an unsafe buffer that does not perform bounds checks}}
+float two_dimension_array(Float4x4& matrix, unsigned idx) {
+  // expected-warning@+1{{unsafe buffer access}}
+  float a = matrix[0][4];
+
+  a = matrix[0][3];
+
+  // expected-note@+1{{used in buffer access here}}
+  a = matrix[4][0];
+
+  a = matrix[idx][0]; // expected-note{{used in buffer access here}}
+
+  a = matrix[0][idx]; //expected-warning{{unsafe buffer access}}
+
+  a = matrix[idx][idx]; //expected-warning{{unsafe buffer access}} // expected-note{{used in buffer access here}}
+
+  return matrix[1][1];
+}
+
+typedef float Float2x3x4[2][3][4];
+float multi_dimension_array(Float2x3x4& matrix) {
+  float *f = matrix[0][2];
+  return matrix[1][2][3];
+}
+
+char array_strings[][11] = {
+  "Apple", "Banana", "Cherry", "Date", "Elderberry"
+};
+
+char array_string[] = "123456";
+
+char access_strings() {
+  char c = array_strings[0][4];
+  c = array_strings[3][10];
+  c = array_string[5];
+  return c;
+}