Multi-dimensional arrays aren't supported by GCC. We'll do the same here and default to llvm.objectsize().

Author: bwendling

clang/lib/CodeGen/CGBuiltin.cpp

@@ -1080,6 +1080,10 @@ class StructFieldAccess
   }
 
   const MemberExpr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
+    if (ASE)
+      // We don't support multiple subscripts.
+      return nullptr;
+
     AddrOfSeen = false; // '&ptr->array[idx]' is okay.
     ASE = E;
     return Visit(E->getBase());

clang/test/CodeGen/attr-counted-by.c

@@ -2083,3 +2083,61 @@ size_t test33(struct annotated *ptr) {
   // Don't handle '&ptr->array' like normal.
   return __bdos(&*&*&*&ptr->array);
 }
+
+struct multi_subscripts {
+  unsigned long flags[42][42];
+  int count;
+  int array[] __counted_by(count);
+};
+
+// SANITIZE-WITH-ATTR-LABEL: define dso_local i64 @test34(
+// SANITIZE-WITH-ATTR-SAME: ptr noundef [[PTR:%.*]], i32 noundef [[IDX1:%.*]], i32 noundef [[IDX2:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// SANITIZE-WITH-ATTR-NEXT:  entry:
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = icmp ult i32 [[IDX1]], 42
+// SANITIZE-WITH-ATTR-NEXT:    br i1 [[TMP0]], label [[CONT1:%.*]], label [[HANDLER_OUT_OF_BOUNDS:%.*]], !prof [[PROF3]], !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR:       handler.out_of_bounds:
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = zext i32 [[IDX1]] to i64, !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR-NEXT:    tail call void @__ubsan_handle_out_of_bounds_abort(ptr nonnull @[[GLOB51:[0-9]+]], i64 [[TMP1]]) #[[ATTR7]], !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR-NEXT:    unreachable, !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR:       cont1:
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP2:%.*]] = icmp ult i32 [[IDX2]], 43
+// SANITIZE-WITH-ATTR-NEXT:    br i1 [[TMP2]], label [[CONT3:%.*]], label [[HANDLER_OUT_OF_BOUNDS2:%.*]], !prof [[PROF3]], !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR:       handler.out_of_bounds2:
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP3:%.*]] = zext i32 [[IDX2]] to i64
+// SANITIZE-WITH-ATTR-NEXT:    tail call void @__ubsan_handle_out_of_bounds_abort(ptr nonnull @[[GLOB52:[0-9]+]], i64 [[TMP3]]) #[[ATTR7]], !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR-NEXT:    unreachable, !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR:       cont3:
+// SANITIZE-WITH-ATTR-NEXT:    ret i64 -1
+//
+// NO-SANITIZE-WITH-ATTR-LABEL: define dso_local i64 @test34(
+// NO-SANITIZE-WITH-ATTR-SAME: ptr noundef readnone [[PTR:%.*]], i32 noundef [[IDX1:%.*]], i32 noundef [[IDX2:%.*]]) local_unnamed_addr #[[ATTR3]] {
+// NO-SANITIZE-WITH-ATTR-NEXT:  entry:
+// NO-SANITIZE-WITH-ATTR-NEXT:    ret i64 -1
+//
+// SANITIZE-WITHOUT-ATTR-LABEL: define dso_local i64 @test34(
+// SANITIZE-WITHOUT-ATTR-SAME: ptr noundef [[PTR:%.*]], i32 noundef [[IDX1:%.*]], i32 noundef [[IDX2:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// SANITIZE-WITHOUT-ATTR-NEXT:  entry:
+// SANITIZE-WITHOUT-ATTR-NEXT:    [[TMP0:%.*]] = icmp ult i32 [[IDX1]], 42
+// SANITIZE-WITHOUT-ATTR-NEXT:    br i1 [[TMP0]], label [[CONT1:%.*]], label [[HANDLER_OUT_OF_BOUNDS:%.*]], !prof [[PROF8]], !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR:       handler.out_of_bounds:
+// SANITIZE-WITHOUT-ATTR-NEXT:    [[TMP1:%.*]] = zext i32 [[IDX1]] to i64, !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR-NEXT:    tail call void @__ubsan_handle_out_of_bounds_abort(ptr nonnull @[[GLOB20:[0-9]+]], i64 [[TMP1]]) #[[ATTR7]], !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR-NEXT:    unreachable, !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR:       cont1:
+// SANITIZE-WITHOUT-ATTR-NEXT:    [[TMP2:%.*]] = icmp ult i32 [[IDX2]], 43
+// SANITIZE-WITHOUT-ATTR-NEXT:    br i1 [[TMP2]], label [[CONT3:%.*]], label [[HANDLER_OUT_OF_BOUNDS2:%.*]], !prof [[PROF8]], !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR:       handler.out_of_bounds2:
+// SANITIZE-WITHOUT-ATTR-NEXT:    [[TMP3:%.*]] = zext i32 [[IDX2]] to i64
+// SANITIZE-WITHOUT-ATTR-NEXT:    tail call void @__ubsan_handle_out_of_bounds_abort(ptr nonnull @[[GLOB21:[0-9]+]], i64 [[TMP3]]) #[[ATTR7]], !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR-NEXT:    unreachable, !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR:       cont3:
+// SANITIZE-WITHOUT-ATTR-NEXT:    ret i64 -1
+//
+// NO-SANITIZE-WITHOUT-ATTR-LABEL: define dso_local i64 @test34(
+// NO-SANITIZE-WITHOUT-ATTR-SAME: ptr noundef readnone [[PTR:%.*]], i32 noundef [[IDX1:%.*]], i32 noundef [[IDX2:%.*]]) local_unnamed_addr #[[ATTR1]] {
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:  entry:
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:    ret i64 -1
+//
+size_t test34(struct multi_subscripts *ptr, int idx1, int idx2) {
+  return __bdos(&ptr->flags[idx1][idx2]);
+}