FindVulkan: Support for finding glslc

The GLSL SPIR-V compiler is part of the Vulkan SDK and may be used
by projects for compiling shaders as part of the build process.
This is not strictly required to build a Vulkan application, which
is why the variable is not part of the REQUIRED_VARs for the module.

Help/release/dev/FindVulkan-glslc.rst

@@ -0,0 +1,10 @@
+FindVulkan-glslc
+----------------
+
+* The :module:`FindVulkan` module gained a new output variable
+  ``Vulkan_GLSLC_EXECUTABLE`` which contains the path to the
+  GLSL SPIR-V compiler.
+
+* The :module:`FindVulkan` module gained a new target
+  ``Vulkan::glslc`` which contains the path to the
+  GLSL SPIR-V compiler.

Modules/FindVulkan.cmake

@@ -14,6 +14,9 @@ IMPORTED Targets
 This module defines :prop_tgt:`IMPORTED` target ``Vulkan::Vulkan``, if
 Vulkan has been found.
 
+This module defines :prop_tgt:`IMPORTED` target ``Vulkan::glslc``, if
+Vulkan and the GLSLC SPIR-V compiler has been found.
+
 Result Variables
 ^^^^^^^^^^^^^^^^
 
@@ -23,10 +26,11 @@ This module defines the following variables::
   Vulkan_INCLUDE_DIRS   - include directories for Vulkan
   Vulkan_LIBRARIES      - link against this library to use Vulkan
 
-The module will also define two cache variables::
+The module will also define three cache variables::
 
-  Vulkan_INCLUDE_DIR    - the Vulkan include directory
+  Vulkan_INCLUDE_DIR        - the Vulkan include directory
-  Vulkan_LIBRARY        - the path to the Vulkan library
+  Vulkan_LIBRARY            - the path to the Vulkan library
+  Vulkan_GLSLC_EXECUTABLE   - the path to the GLSL SPIR-V compiler
 
 Hints
 ^^^^^
@@ -53,6 +57,11 @@ if(WIN32)
         "$ENV{VULKAN_SDK}/Lib"
         "$ENV{VULKAN_SDK}/Bin"
       )
+    find_program(Vulkan_GLSLC_EXECUTABLE
+      NAMES glslc
+      HINTS
+        "$ENV{VULKAN_SDK}/Bin"
+      )
   elseif(CMAKE_SIZEOF_VOID_P EQUAL 4)
     find_library(Vulkan_LIBRARY
       NAMES vulkan-1
@@ -60,6 +69,11 @@ if(WIN32)
         "$ENV{VULKAN_SDK}/Lib32"
         "$ENV{VULKAN_SDK}/Bin32"
       )
+    find_program(Vulkan_GLSLC_EXECUTABLE
+      NAMES glslc
+      HINTS
+        "$ENV{VULKAN_SDK}/Bin32"
+      )
   endif()
 else()
   find_path(Vulkan_INCLUDE_DIR
@@ -68,6 +82,9 @@ else()
   find_library(Vulkan_LIBRARY
     NAMES vulkan
     HINTS "$ENV{VULKAN_SDK}/lib")
+  find_program(Vulkan_GLSLC_EXECUTABLE
+    NAMES glslc
+    HINTS "$ENV{VULKAN_SDK}/bin")
 endif()
 
 set(Vulkan_LIBRARIES ${Vulkan_LIBRARY})
@@ -78,7 +95,7 @@ find_package_handle_standard_args(Vulkan
   DEFAULT_MSG
   Vulkan_LIBRARY Vulkan_INCLUDE_DIR)
 
-mark_as_advanced(Vulkan_INCLUDE_DIR Vulkan_LIBRARY)
+mark_as_advanced(Vulkan_INCLUDE_DIR Vulkan_LIBRARY Vulkan_GLSLC_EXECUTABLE)
 
 if(Vulkan_FOUND AND NOT TARGET Vulkan::Vulkan)
   add_library(Vulkan::Vulkan UNKNOWN IMPORTED)
@@ -86,3 +103,8 @@ if(Vulkan_FOUND AND NOT TARGET Vulkan::Vulkan)
     IMPORTED_LOCATION "${Vulkan_LIBRARIES}"
     INTERFACE_INCLUDE_DIRECTORIES "${Vulkan_INCLUDE_DIRS}")
 endif()
+
+if(Vulkan_FOUND AND Vulkan_GLSLC_EXECUTABLE AND NOT TARGET Vulkan::glslc)
+  add_executable(Vulkan::glslc IMPORTED)
+  set_property(TARGET Vulkan::glslc PROPERTY IMPORTED_LOCATION "${Vulkan_GLSLC_EXECUTABLE}")
+endif()

Tests/FindVulkan/Test/CMakeLists.txt

@@ -13,3 +13,12 @@ add_executable(test_var main.c)
 target_include_directories(test_var PRIVATE ${Vulkan_INCLUDE_DIRS})
 target_link_libraries(test_var PRIVATE ${Vulkan_LIBRARIES})
 add_test(NAME test_var COMMAND test_var)
+
+if(Vulkan_GLSLC_EXECUTABLE)
+  add_test(NAME test_glslc
+    COMMAND ${CMAKE_COMMAND}
+    "-DVULKAN_GLSLC_EXECUTABLE=${Vulkan_GLSLC_EXECUTABLE}"
+    "-DVULKAN_GLSLC_EXECUTABLE_TARGET=$<TARGET_FILE:Vulkan::glslc>"
+    -P "${CMAKE_CURRENT_LIST_DIR}/Run-glslc.cmake"
+    )
+endif()

Tests/FindVulkan/Test/Run-glslc.cmake

@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.12)
+
+function(run_glslc exe exe_display)
+  execute_process(COMMAND ${exe} --help
+    OUTPUT_VARIABLE output
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    RESULT_VARIABLE result
+    )
+
+  if(NOT result EQUAL 0)
+    message(SEND_ERROR "Result of ${exe_display} --help is ${result}, should be 0")
+  endif()
+
+  if(NOT output MATCHES "^glslc - Compile shaders into SPIR-V")
+    message(SEND_ERROR "Output of ${exe_display} --help is \"${output}\", should begin with \"glslc - Compile shaders into SPIR-V\"")
+  endif()
+endfunction()
+
+run_glslc("${VULKAN_GLSLC_EXECUTABLE}" "\${VULKAN_GLSLC_EXECUTABLE}")
+run_glslc("${VULKAN_GLSLC_EXECUTABLE_TARGET}" "Vulkan::glslc")

Tests/FindVulkan/Test/main.c

@@ -2,10 +2,10 @@
 
 int main()
 {
-  VkInstanceCreateInfo instanceCreateInfo = {};
+  VkInstanceCreateInfo instanceCreateInfo = { 0 };
   instanceCreateInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
 
-  VkApplicationInfo applicationInfo = {};
+  VkApplicationInfo applicationInfo = { 0 };
   applicationInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
   applicationInfo.apiVersion = VK_API_VERSION_1_0;
   applicationInfo.applicationVersion = VK_MAKE_VERSION(1, 0, 0);