Fix GCC warnings

Change-Id: I9c719298a25d28f964c0a987c35fc94426807d51
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/28180
Commit-Queue: Sarah Mashayekhi <sarahmashay@google.com>
Reviewed-by: Sarah Mashayekhi <sarahmashay@google.com>

src/validator_impl.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <cassert>
 #include "src/validator_impl.h"
 #include "src/ast/call_statement.h"
 #include "src/ast/function.h"
@@ -90,8 +91,9 @@ bool ValidatorImpl::ValidateEntryPoints(const ast::EntryPointList& eps) {
       return false;
     }
 
-    ast::Function* func;
+    ast::Function* func = nullptr;
     function_stack_.get(ep_ptr->function_name(), &func);
+
     if (!func->return_type()->IsVoid()) {
       set_error(ep_ptr->source(),
                 "v-0024: Entry point function must return void: '" +

src/writer/spirv/builder.h

@@ -289,11 +289,14 @@ class Builder {
   /// Generates a texture intrinsic call
   /// @param name the texture intrinsic name
   /// @param call the call expression
+  /// @param result_id result ID of the texture instruction
+  /// @param wgsl_params SPIR-V arguments for WGSL-specific intrinsic's call
+  /// parameters
   /// @returns the expression ID on success or 0 otherwise
   uint32_t GenerateTextureIntrinsic(const std::string& name,
                                     ast::CallExpression* call,
                                     uint32_t result_id,
-                                    OperandList params);
+                                    OperandList wgsl_params);
   /// Generates a sampled image
   /// @param texture_type the texture type
   /// @param texture_operand the texture operand

src/writer/writer.h

@@ -32,6 +32,7 @@ class Writer {
   const std::string& error() const { return error_; }
 
   /// Resets the generator
+  /// @returns nothing
   virtual void Reset() = 0;
 
   /// Converts the module into the desired format