layers: GH616 Improve descriptor set invalid binding handling

Prior to calls to get an global index from a binding, make sure that
HasBinding() is called to verify that the binding exists.
Added HasBinding() calls to a couple of validation functions for
early exist.
Updated code comment to indicate that HasBinding() call should
precede GetGlobal*IndexFromBinding() calls.
Added assert() to GetGlobal*IndexFromBinding() calls in the error case
to make error more obvious in debug builds.
Note that Perform*Update() functions already indicate that they should
be preceded by their matching Validate*Update() functions, which include
the appropriate checks for HasBinding().
case the Validate*Update() funciont

2 files changed, 14 insertions, 0 deletions

diff --git a/layers/descriptor_sets.cpp b/layers/descriptor_sets.cpp
index 9f3b239d..1f72d447 100644
--- a/layers/descriptor_sets.cpp
+++ b/layers/descriptor_sets.cpp
@@ -131,6 +131,7 @@ uint32_t cvdescriptorset::DescriptorSetLayout::GetGlobalStartIndexFromBinding(co
         return btgsi_itr->second;
     }
     // In error case max uint32_t so index is out of bounds to break ASAP
+    assert(0);
     return 0xFFFFFFFF;
 }
 // For the given binding, return end index
@@ -141,6 +142,7 @@ uint32_t cvdescriptorset::DescriptorSetLayout::GetGlobalEndIndexFromBinding(cons
         return btgei_itr->second;
     }
     // In error case max uint32_t so index is out of bounds to break ASAP
+    assert(0);
     return 0xFFFFFFFF;
 }
 // For given binding, return ptr to ImmutableSampler array
@@ -337,6 +339,13 @@ bool cvdescriptorset::DescriptorSet::ValidateDrawState(const std::unordered_set<
                                                        const std::vector<uint32_t> &dynamic_offsets, std::string *error) const {
     auto dyn_offset_index = 0;
     for (auto binding : bindings) {
+        if (!p_layout_->HasBinding(binding)) {
+            std::stringstream error_str;
+            error_str << "Attempting to validate DrawState for binding #" << binding
+                      << " which is an invalid binding for this descriptor set.";
+            *error = error_str.str();
+            return false;
+        }
         auto start_idx = p_layout_->GetGlobalStartIndexFromBinding(binding);
         if (descriptors_[start_idx]->IsImmutableSampler()) {
             // Nothing to do for strictly immutable sampler
@@ -413,6 +422,10 @@ uint32_t cvdescriptorset::DescriptorSet::GetStorageUpdates(const std::unordered_
                                                            std::unordered_set<VkImageView> *image_set) const {
     auto num_updates = 0;
     for (auto binding : bindings) {
+        // If a binding doesn't exist, skip it
+        if (!p_layout_->HasBinding(binding)) {
+            continue;
+        }
         auto start_idx = p_layout_->GetGlobalStartIndexFromBinding(binding);
         if (descriptors_[start_idx]->IsStorage()) {
             if (Image == descriptors_[start_idx]->descriptor_class) {
diff --git a/layers/descriptor_sets.h b/layers/descriptor_sets.h
index 98ab1447..92824597 100644
--- a/layers/descriptor_sets.h
+++ b/layers/descriptor_sets.h
@@ -115,6 +115,7 @@ class DescriptorSetLayout {
     VkSampler const *GetImmutableSamplerPtrFromBinding(const uint32_t) const;
     VkSampler const *GetImmutableSamplerPtrFromIndex(const uint32_t) const;
     // For a particular binding, get the global index
+    //  These calls should be guarded by a call to "HasBinding(binding)" to verify that the given binding exists
     uint32_t GetGlobalStartIndexFromBinding(const uint32_t) const;
     uint32_t GetGlobalEndIndexFromBinding(const uint32_t) const;
     // For a particular binding starting at offset and having update_count descriptors