layers:Handle consecutive descriptor updates

Fixes #1165

According to spec descriptor updates should roll over to the next
binding number. If bindings were out of order, this was broken in
validation.

This fix corrects validation and state update for out-of-order
descriptor bindings by checking consecutive updates based on correct
binding count for consecutive bindings and by performing updates
on a per-binding basis, making sure to roll update over to the
correct next binding.

Also update the error message, related negative test, and database
file.

1 files changed, 36 insertions, 9 deletions

diff --git a/layers/descriptor_sets.cpp b/layers/descriptor_sets.cpp
index cf2229aa..142f1eff 100644
--- a/layers/descriptor_sets.cpp
+++ b/layers/descriptor_sets.cpp
@@ -18,6 +18,9 @@
  * Author: Tobin Ehlis <tobine@google.com>
  */
 
+// Allow use of STL min and max functions in Windows
+#define NOMINMAX
+
 #include "descriptor_sets.h"
 #include "vk_enum_string_helper.h"
 #include "vk_safe_struct.h"
@@ -74,6 +77,18 @@ bool cvdescriptorset::DescriptorSetLayout::ValidateCreateInfo(debug_report_data
     return skip;
 }
 
+// Return the number of descriptors for the given binding and all successive bindings
+uint32_t cvdescriptorset::DescriptorSetLayout::GetConsecutiveDescriptorCountFromBinding(uint32_t binding) const {
+    // If binding is invalid we'll return 0
+    uint32_t binding_count = 0;
+    auto bi_itr = binding_to_index_map_.find(binding);
+    while (bi_itr != binding_to_index_map_.end()) {
+        binding_count += bindings_[bi_itr->second].descriptorCount;
+        bi_itr++;
+    }
+    return binding_count;
+}
+
 // put all bindings into the given set
 void cvdescriptorset::DescriptorSetLayout::FillBindingSet(std::unordered_set<uint32_t> *binding_set) const {
     for (auto binding_index_pair : binding_to_index_map_)
@@ -546,10 +561,21 @@ void cvdescriptorset::DescriptorSet::InvalidateBoundCmdBuffers() {
 }
 // Perform write update in given update struct
 void cvdescriptorset::DescriptorSet::PerformWriteUpdate(const VkWriteDescriptorSet *update) {
-    auto start_idx = p_layout_->GetGlobalStartIndexFromBinding(update->dstBinding) + update->dstArrayElement;
-    // perform update
-    for (uint32_t di = 0; di < update->descriptorCount; ++di) {
-        descriptors_[start_idx + di]->WriteUpdate(update, di);
+    // Perform update on a per-binding basis as consecutive updates roll over to next binding
+    auto descriptors_remaining = update->descriptorCount;
+    auto binding_being_updated = update->dstBinding;
+    auto offset = update->dstArrayElement;
+    while (descriptors_remaining) {
+        uint32_t update_count = std::min(descriptors_remaining, GetDescriptorCountFromBinding(binding_being_updated));
+        auto global_idx = p_layout_->GetGlobalStartIndexFromBinding(binding_being_updated) + offset;
+        // Loop over the updates for a single binding at a time
+        for (uint32_t di = 0; di < update_count; ++di) {
+            descriptors_[global_idx + di]->WriteUpdate(update, di);
+        }
+        // Roll over to next binding in case of consecutive update
+        descriptors_remaining -= update_count;
+        offset = 0;
+        binding_being_updated++;
     }
     if (update->descriptorCount)
         some_update_ = true;
@@ -1169,14 +1195,15 @@ bool cvdescriptorset::DescriptorSet::ValidateWriteUpdate(const debug_report_data
         *error_msg = error_str.str();
         return false;
     }
-    if ((start_idx + update->descriptorCount) > p_layout_->GetTotalDescriptorCount()) {
+    if (update->descriptorCount >
+        (p_layout_->GetConsecutiveDescriptorCountFromBinding(update->dstBinding) - update->dstArrayElement)) {
         *error_code = VALIDATION_ERROR_00938;
         std::stringstream error_str;
         error_str << "Attempting write update to descriptor set " << set_ << " binding #" << update->dstBinding << " with "
-                  << p_layout_->GetTotalDescriptorCount() << " total descriptors but update of " << update->descriptorCount
-                  << " descriptors starting at binding offset of " << p_layout_->GetGlobalStartIndexFromBinding(update->dstBinding)
-                  << " combined with update array element offset of " << update->dstArrayElement
-                  << " oversteps the size of this descriptor set";
+                  << p_layout_->GetConsecutiveDescriptorCountFromBinding(update->dstBinding)
+                  << " descriptors in that binding and all successive bindings of the set, but update of "
+                  << update->descriptorCount << " descriptors combined with update array element offset of "
+                  << update->dstArrayElement << " oversteps the available number of consecutive descriptors";
         *error_msg = error_str.str();
         return false;
     }