memory: Improve null pointer and unmapped memory handling

- Update vcpkg baseline to a42af01b72c28a8e1d7b48107b33e4f286a55ef6
- Add SPIRV-Tools and SPIRV-Headers as submodules
- Update Vulkan-related submodules to latest stable versions
- Improve memory access error handling:
  - Add specific handling for null pointer accesses in ARM32 emulation
  - Return 0 for null pointer reads instead of undefined behavior
  - Silently ignore writes to null pointers
  - Add more detailed error messages distinguishing between null pointer
    access and other unmapped memory errors
  - Treat addresses below 0x1000 as potential null pointer accesses

These changes should provide more graceful handling of null pointer
accesses and improve stability when running games that attempt invalid
memory operations.

.gitmodules

@@ -67,3 +67,9 @@
 [submodule "Vulkan-Utility-Libraries"]
 	path = externals/Vulkan-Utility-Libraries
 	url = https://github.com/KhronosGroup/Vulkan-Utility-Libraries.git
+[submodule "externals/SPIRV-Tools"]
+	path = externals/SPIRV-Tools
+	url = https://github.com/KhronosGroup/SPIRV-Tools.git
+[submodule "externals/SPIRV-Headers"]
+	path = externals/SPIRV-Headers
+	url = https://github.com/KhronosGroup/SPIRV-Headers.git

externals/SPIRV-Headers

@@ -0,0 +1 @@
+Subproject commit 2b2e05e088841c63c0b6fd4c9fb380d8688738d3

externals/SPIRV-Tools

@@ -0,0 +1 @@
+Subproject commit b9d5ced92ac454caf526c3b80d5105a1f38878ce

externals/Vulkan-Headers

@@ -1 +1 @@
-Subproject commit d4a196d8c84e032d27f999adcea3075517c1c97f
+Subproject commit a03d2f6d5753b365d704d58161825890baad0755

externals/Vulkan-Utility-Libraries

@@ -1 +1 @@
-Subproject commit 5a88b6042edb8f03eefc8de73bd73a899989373f
+Subproject commit 7b23ba7a5f86936a8d783baf64a77c38977d6890

externals/VulkanMemoryAllocator

@@ -1 +1 @@
-Subproject commit f74c2d906f1537114fe0c0d855d5d27db91898cb
+Subproject commit 7ab8483d10b665ba8d478e1502380c40e2374ac7

externals/vcpkg

@@ -1 +1 @@
-Subproject commit d4f3e122069912636c123b7ece673f6e01513cea
+Subproject commit cf035d9916a0a23042b41fcae7ee0386d245af08

src/core/arm/dynarmic/arm_dynarmic_32.cpp

@@ -95,6 +95,13 @@ public:
             LOG_CRITICAL(Core_ARM, "Cannot execute instruction at unmapped address {:#08x}", pc);
             ReturnException(pc, PrefetchAbort);
             return;
+        case Dynarmic::A32::Exception::AccessViolation:
+            if (pc == 0 || pc < 0x1000) {
+                LOG_CRITICAL(Core_ARM, "Null pointer dereference at {:#08x}", pc);
+                ReturnException(pc, DataAbort);
+                return;
+            }
+            [[fallthrough]];
         default:
             if (m_debugger_enabled) {
                 ReturnException(pc, InstructionBreakpoint);

src/core/memory.cpp

@@ -737,12 +737,21 @@ struct Memory::Impl {
         const u8* const ptr = GetPointerImpl(
             GetInteger(vaddr),
             [vaddr]() {
+                // Add special handling for null pointer reads
+                if (GetInteger(vaddr) == 0 || GetInteger(vaddr) < 0x1000) {
+                    LOG_ERROR(HW_Memory, "Null pointer Read{} @ 0x{:016X}", sizeof(T) * 8,
+                              GetInteger(vaddr));
+                    return;
+                }
                 LOG_ERROR(HW_Memory, "Unmapped Read{} @ 0x{:016X}", sizeof(T) * 8,
                           GetInteger(vaddr));
             },
             [&]() { HandleRasterizerDownload(GetInteger(vaddr), sizeof(T)); });
         if (ptr) {
             std::memcpy(&result, ptr, sizeof(T));
+        } else if (GetInteger(vaddr) == 0) {
+            // Return 0 for null pointer reads instead of random memory
+            result = 0;
         }
         return result;
     }
@@ -761,6 +770,12 @@ struct Memory::Impl {
         u8* const ptr = GetPointerImpl(
             GetInteger(vaddr),
             [vaddr, data]() {
+                // Add special handling for null pointer writes
+                if (GetInteger(vaddr) == 0 || GetInteger(vaddr) < 0x1000) {
+                    LOG_ERROR(HW_Memory, "Null pointer Write{} @ 0x{:016X} = 0x{:016X}", sizeof(T) * 8,
+                              GetInteger(vaddr), static_cast<u64>(data));
+                    return;
+                }
                 LOG_ERROR(HW_Memory, "Unmapped Write{} @ 0x{:016X} = 0x{:016X}", sizeof(T) * 8,
                           GetInteger(vaddr), static_cast<u64>(data));
             },
@@ -768,6 +783,7 @@ struct Memory::Impl {
         if (ptr) {
             std::memcpy(ptr, &data, sizeof(T));
         }
+        // Silently ignore writes to null pointer
     }
 
     template <typename T>

vcpkg.json

@@ -1,7 +1,7 @@
 {
     "$schema": "https://raw.githubusercontent.com/microsoft/vcpkg-tool/main/docs/vcpkg.schema.json",
     "name": "citron",
-    "builtin-baseline": "7adc2e4d49e8d0efc07a369079faa6bc3dbb90f3",
+    "builtin-baseline": "a42af01b72c28a8e1d7b48107b33e4f286a55ef6",
     "version": "1.0",
     "dependencies": [
         "boost-algorithm",