Improve error messages for tensor size errors (pytorch#7453)

Summary:

Print expected and actual tensor sizes when attempting to resize a static tensor.  This commonly comes up when a user provides an incorrectly-shaped input tensor and can be confusing. Adding the expected and actual sizes should make this situation more intuitive.

This change also includes ET_UNUSED in several places where the variable is used only when logging is enabled, as unused variable warnings cause build failures in some build modes when logging is disabled.

Differential Revision: D67665846

Author: GregoryComer

runtime/core/exec_aten/util/dim_order_util.h

@@ -9,6 +9,8 @@
 #pragma once
 
 #include <cstdint>
+#include <cstdio>
+#include <cstring>
 
 #include <executorch/runtime/core/error.h>
 #include <executorch/runtime/platform/assert.h>
@@ -257,6 +259,33 @@ ET_NODISCARD inline Error stride_to_dim_order(
   }
   return Error::Ok;
 }
+
+/**
+ * Print a string representation of an ArrayRef of tensor sizes into a
+ * user-provided string buffer. If the user buffer is too small, the string
+ * will be truncated. The output is of the format (1,2,3,4).
+ * 
+ * Note that we cannot use ArrayRef here due to a circular dependency (see
+ * above comments).
+ */
+template <class SizesType>
+inline void sizes_to_string(char* output, size_t output_size, SizesType* sizes, size_t rank) {
+  auto remaining_size = output_size;
+  for (auto i = 0; remaining_size > 0 && i < rank; i++) {
+    snprintf(
+        output,
+        remaining_size,
+        "%s%zd",
+        i == 0 ? "(" : ",",
+        static_cast<size_t>(sizes[i]));
+    auto len = strlen(output);
+    output += len;
+    remaining_size -= len;
+  }
+  snprintf(output, remaining_size, ")");
+}
+
+
 } // namespace runtime
 } // namespace executorch
 

runtime/core/portable_type/tensor_impl.cpp

@@ -90,24 +90,39 @@ Error TensorImpl::internal_resize_contiguous(ArrayRef<SizesType> new_sizes) {
   if (dim_ == 0) {
     return Error::Ok;
   }
+
+
   switch (shape_dynamism_) {
     case TensorShapeDynamism::STATIC:
-      ET_CHECK_OR_RETURN_ERROR(
-          std::equal(sizes_, sizes_ + dim_, new_sizes.begin()),
-          NotSupported,
-          "Attempted to resize a static tensor");
+      if (!std::equal(sizes_, sizes_ + dim_, new_sizes.begin())) {
+#ifdef ET_LOG_ENABLED
+        std::array<char, 5> old_sizes_str, new_sizes_str;
+
+        executorch::runtime::sizes_to_string(old_sizes_str.data(), old_sizes_str.size(), sizes().data(), sizes().size());
+        executorch::runtime::sizes_to_string(new_sizes_str.data(), new_sizes_str.size(), new_sizes.data(), new_sizes.size());
+#endif
+
+        ET_CHECK_OR_RETURN_ERROR(
+            false,
+            NotSupported,
+            "Attempted to resize a static tensor. Expected shape %s, but received %s.",
+            old_sizes_str.data(),
+            new_sizes_str.data())
+      }
+
       break;
     case TensorShapeDynamism::DYNAMIC_BOUND:
       // TODO(T175194371): Unbounded dynamic tensor resizing is not yet
       // supported: treat them as upper-bounded.
     case TensorShapeDynamism::DYNAMIC_UNBOUND: {
       const auto new_numel = compute_numel(new_sizes.data(), dim_);
+
       ET_CHECK_OR_RETURN_ERROR(
           new_numel <= numel_bound_,
           NotSupported,
-          "Attempted to resize a bounded tensor with capacity of %zu elements to %zu elements.",
-          new_numel,
-          numel_bound_);
+          "Attempted to resize a bounded tensor with a maximum capacity of %zu elements to %zu elements.",
+          numel_bound_,
+          new_numel);
 
       if (strides_ && dim_order_) {
         auto error =

runtime/executor/method.cpp

@@ -1061,7 +1061,7 @@ Error Method::execute_instruction() {
         // We know that instr_args_as_KernelCall is non-null because it was
         // checked at init time.
         auto op_index = instruction->instr_args_as_KernelCall()->op_index();
-        auto op = serialization_plan_->operators()->Get(op_index);
+        ET_UNUSED auto op = serialization_plan_->operators()->Get(op_index);
         ET_LOG(
             Error,
             "KernelCall failed at instruction %zu:%zu in operator %s.%s: 0x%x",

runtime/kernel/operator_registry.cpp

@@ -74,7 +74,7 @@ Error register_kernels_internal(const Span<const Kernel> kernels) {
     return Error::Internal;
   }
   // for debugging purpose
-  const char* lib_name = et_pal_get_shared_library_name(kernels.data());
+  ET_UNUSED const char* lib_name = et_pal_get_shared_library_name(kernels.data());
 
   for (const auto& kernel : kernels) {
     // Linear search. This is fine if the number of kernels is small.