Generate the Vulkan shaders at build time

Use `add_custom_command` and `add_custom_target` instead of
`execute_process` so the generation of the Vulkan shader is done at
build time and not configuration time.

Use `configure_file` instead of string replacement.

Signed-off-by: Ahmed Hesham <ahmed.hesham@arm.com>

test_conformance/vulkan/CMakeLists.txt

@@ -32,3 +32,5 @@ include_directories("../common/vulkan_wrapper")
 add_subdirectory(shaders)
 
 include(../CMakeCommon.txt)
+
+add_dependencies(${${MODULE_NAME}_OUT} vulkan_shaders)

test_conformance/vulkan/shaders/CMakeLists.txt

@@ -1,5 +1,3 @@
-# CMP0007:NEW - Don't ignore empty elements in a list
-cmake_policy(SET CMP0007 NEW)
 find_program(
     Vulkan_glslang_binary
     NAMES glslang
@@ -10,40 +8,36 @@ if(${Vulkan_glslang_binary} STREQUAL "Vulkan_glslang_binary-NOTFOUND")
 else()
     message(STATUS "Found glslang: ${Vulkan_glslang_binary}")
 
-    set(IMAGE2D_SHADER_IN_FILE "image2D.comp")
-    set(IMAGE2D_SHADER_TMP_OUT_FILE "tmp_image2D.comp")
-    set(BUFFER_SHADER_IN_FILE "buffer")
-    set(IMAGE2D_FORMATS_LIST_IN_FILE "image2D_test_formats.txt")
-
-    file(READ ${IMAGE2D_SHADER_IN_FILE} IMAGE2D_SHADER_UNFORMAT_CONTENT)
-    file(STRINGS ${IMAGE2D_FORMATS_LIST_IN_FILE} IMAGE2D_FORMATS_LIST)
-
-    if(NOT DEFINED VULKAN_TEST_RESOURCES)
-        set(VULKAN_TEST_RESOURCES ${CMAKE_CURRENT_BINARY_DIR})
-    endif()
-
-    foreach(IMAGE2D_FORMAT ${IMAGE2D_FORMATS_LIST})
-        list(GET IMAGE2D_FORMAT 1 GLSL_FORMAT)
-        list(GET IMAGE2D_FORMAT 2 GLSL_TYPE_PREFIX)
-        string(REPLACE "GLSL_FORMAT" "${GLSL_FORMAT}" IMAGE2D_SHADER_CONTENT "${IMAGE2D_SHADER_UNFORMAT_CONTENT}")
-        string(REPLACE "GLSL_TYPE_PREFIX" "${GLSL_TYPE_PREFIX}" IMAGE2D_SHADER_CONTENT "${IMAGE2D_SHADER_CONTENT}")
-        file(WRITE ${IMAGE2D_SHADER_TMP_OUT_FILE} "${IMAGE2D_SHADER_CONTENT}")
-        execute_process(
-            COMMAND ${Vulkan_glslang_binary} --target-env vulkan1.0 -o ${VULKAN_TEST_RESOURCES}/image2D_${GLSL_FORMAT}.spv ${IMAGE2D_SHADER_TMP_OUT_FILE}
-            WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-            RESULT_VARIABLE commandStatus
-            OUTPUT_QUIET)
-        if(commandStatus AND NOT commandStatus EQUAL 0)
-            message(FATAL_ERROR "shader -> spir-v compilation failed")
-        endif()
-    endforeach(IMAGE2D_FORMAT)
-    execute_process(
-        COMMAND ${Vulkan_glslang_binary} --target-env vulkan1.0 -o ${VULKAN_TEST_RESOURCES}/${BUFFER_SHADER_IN_FILE}.spv ${BUFFER_SHADER_IN_FILE}.comp
-        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-        RESULT_VARIABLE commandStatus
-        OUTPUT_QUIET)
-    if(commandStatus AND NOT commandStatus EQUAL 0)
-        message(FATAL_ERROR "shader -> spir-v compilation failed")
-    endif()
-    file(REMOVE ${IMAGE2D_SHADER_TMP_OUT_FILE})
-endif()
+    set(vulkan_spirv_files "")
+
+    add_custom_command(
+      OUTPUT buffer.spv
+      COMMAND ${Vulkan_glslang_binary}
+              --target-env vulkan1.0
+              -o ${CMAKE_CURRENT_BINARY_DIR}/buffer.spv
+              ${CMAKE_CURRENT_SOURCE_DIR}/buffer.comp
+      DEPENDS buffer.comp
+      VERBATIM)
+    list(APPEND vulkan_spirv_files ${CMAKE_CURRENT_BINARY_DIR}/buffer.spv)
+
+    file(STRINGS "image2D_test_formats.txt" image2D_formats)
+
+    foreach(format ${image2D_formats})
+        list(GET format 1 GLSL_FORMAT)
+        list(GET format 2 GLSL_TYPE_PREFIX)
+
+        configure_file(image2D.comp.in image2D_${GLSL_FORMAT}.comp)
+
+        add_custom_command(
+          OUTPUT image2D_${GLSL_FORMAT}.spv
+          COMMAND ${Vulkan_glslang_binary}
+                  --target-env vulkan1.0
+                  -o ${CMAKE_CURRENT_BINARY_DIR}/image2D_${GLSL_FORMAT}.spv
+                  ${CMAKE_CURRENT_BINARY_DIR}/image2D_${GLSL_FORMAT}.comp
+          DEPENDS image2D_${GLSL_FORMAT}.comp
+          VERBATIM)
+        list(APPEND vulkan_spirv_files ${CMAKE_CURRENT_BINARY_DIR}/image2D_${GLSL_FORMAT}.spv)
+    endforeach()
+
+    add_custom_target(vulkan_shaders DEPENDS ${vulkan_spirv_files})
+endif()