VULKAN: Fix shader module lifetime bugs in SDR pipeline creation

Fixes startup crash on Windows Vulkan introduced by 8fa8418.

Two bugs in the SDR pipeline creation path when HDR is supported:

1. SDR display pipelines 0-3 were created after the alpha_blend
   fragment shader module had already been destroyed.  The
   alpha_blend_sdr pipeline was created, then the fragment
   shader module was immediately destroyed (line 3692 in the
   original patch).  The subsequent display pipeline loop
   (pipelines_sdr[0..3]) still referenced that destroyed module
   through the pipe struct, producing an invalid VkShaderModule
   handle passed to vkCreateGraphicsPipelines.

   Fix: keep both the vertex and fragment shader modules alive
   through the display 0-3 loop, then destroy both afterward.

2. After the SDR menu shader loop (pipelines_sdr[6+]), an extra
   vkDestroyShaderModule call destroyed shader_stages[0].module
   which had already been destroyed in the loop's last iteration
   at line 3782.  Double-free on a VkShaderModule handle.

   Fix: remove the spurious destroy after the loop.

Both bugs only manifest when VK_CTX_FLAG_HDR_SUPPORT is set
(Windows with HDR-capable displays, or any platform where the
Vulkan driver reports HDR swapchain support).  Non-HDR paths
are unaffected because the entire SDR pipeline block is guarded
by the HDR support check.

Author: LibretroAdmin

gfx/drivers/vulkan.c

@@ -3689,9 +3689,11 @@ static void vulkan_init_pipelines(vk_t *vk)
 
       vkCreateGraphicsPipelines(vk->context->device, vk->pipelines.cache,
             1, &pipe, NULL, &vk->pipelines.alpha_blend_sdr);
-      vkDestroyShaderModule(vk->context->device, shader_stages[1].module, NULL);
 
-      /* SDR display pipelines 0-3 */
+      /* SDR display pipelines 0-3.
+       * Reuse the alpha_blend vertex shader (stages[0]) and
+       * alpha_blend fragment shader (stages[1]) still alive
+       * from just above. */
       for (i = 0; i < 4; i++)
       {
          input_assembly.topology = i & 2 ?
@@ -3702,6 +3704,10 @@ static void vulkan_init_pipelines(vk_t *vk)
                1, &pipe, NULL, &vk->display.pipelines_sdr[i]);
       }
 
+      /* Done with the alpha_blend shader modules. */
+      vkDestroyShaderModule(vk->context->device, shader_stages[0].module, NULL);
+      vkDestroyShaderModule(vk->context->device, shader_stages[1].module, NULL);
+
       /* SDR menu shader pipelines 6+ */
       for (i = 0; i < (int)ARRAY_SIZE(vk->display.pipelines) - 6; i++)
       {
@@ -3782,8 +3788,6 @@ static void vulkan_init_pipelines(vk_t *vk)
          vkDestroyShaderModule(vk->context->device, shader_stages[0].module, NULL);
          vkDestroyShaderModule(vk->context->device, shader_stages[1].module, NULL);
       }
-
-      vkDestroyShaderModule(vk->context->device, shader_stages[0].module, NULL);
    }
 #endif /* VULKAN_HDR_SWAPCHAIN */