[tint][fuzz][ast] Add PreservePadding fuzzer

Bug: tint:2223
Change-Id: I11090a122c1566cdb84ceee38525fca2689ef500
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/186041
Reviewed-by: James Price <jrprice@google.com>

src/tint/lang/wgsl/ast/transform/BUILD.cmake

diff --git a/src/tint/lang/wgsl/ast/transform/BUILD.cmake b/src/tint/lang/wgsl/ast/transform/BUILD.cmake
index dc88a54..8845e90 100644
--- a/src/tint/lang/wgsl/ast/transform/BUILD.cmake
+++ b/src/tint/lang/wgsl/ast/transform/BUILD.cmake
@@ -263,6 +263,7 @@
   lang/wgsl/ast/transform/fold_constants_fuzz.cc
   lang/wgsl/ast/transform/multiplanar_external_texture_fuzz.cc
   lang/wgsl/ast/transform/offset_first_index_fuzz.cc
+  lang/wgsl/ast/transform/preserve_padding_fuzz.cc
   lang/wgsl/ast/transform/zero_init_workgroup_memory_fuzz.cc
 )
 

src/tint/lang/wgsl/ast/transform/BUILD.gn

diff --git a/src/tint/lang/wgsl/ast/transform/BUILD.gn b/src/tint/lang/wgsl/ast/transform/BUILD.gn
index 62c35ca..107c492 100644
--- a/src/tint/lang/wgsl/ast/transform/BUILD.gn
+++ b/src/tint/lang/wgsl/ast/transform/BUILD.gn
@@ -253,6 +253,7 @@
       "fold_constants_fuzz.cc",
       "multiplanar_external_texture_fuzz.cc",
       "offset_first_index_fuzz.cc",
+      "preserve_padding_fuzz.cc",
       "zero_init_workgroup_memory_fuzz.cc",
     ]
     deps = [

src/tint/lang/wgsl/ast/transform/preserve_padding_fuzz.cc

diff --git a/src/tint/lang/wgsl/ast/transform/preserve_padding_fuzz.cc b/src/tint/lang/wgsl/ast/transform/preserve_padding_fuzz.cc
new file mode 100644
index 0000000..486a65a
--- /dev/null
+++ b/src/tint/lang/wgsl/ast/transform/preserve_padding_fuzz.cc
@@ -0,0 +1,46 @@
+// Copyright 2024 The Dawn & Tint Authors
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+//    list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//    this list of conditions and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its
+//    contributors may be used to endorse or promote products derived from
+//    this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "src/tint/cmd/fuzz/wgsl/fuzz.h"
+#include "src/tint/lang/wgsl/ast/transform/preserve_padding.h"
+
+namespace tint::ast::transform {
+namespace {
+
+void PreservePaddingFuzzer(const Program& program) {
+    DataMap outputs;
+    if (auto result = PreservePadding{}.Apply(program, DataMap{}, outputs)) {
+        if (!result->IsValid()) {
+            TINT_ICE() << "PreservePadding returned invalid program:\n" << result->Diagnostics();
+        }
+    }
+}
+
+}  // namespace
+}  // namespace tint::ast::transform
+
+TINT_WGSL_PROGRAM_FUZZER(tint::ast::transform::PreservePaddingFuzzer);