host_shaders: Modify shader cmake integration to allow for larger shaders

using a raw string to encapsulate the entire shader code limits us to shaders of size less than 2KB. This change overcomes this limitation.

src/video_core/host_shaders/CMakeLists.txt

@@ -1,4 +1,5 @@
 set(SHADER_FILES
+    astc_decoder.comp
     block_linear_unswizzle_2d.comp
     block_linear_unswizzle_3d.comp
     convert_depth_to_float.frag

src/video_core/host_shaders/StringShaderHeader.cmake

@@ -6,7 +6,27 @@ get_filename_component(CONTENTS_NAME ${SOURCE_FILE} NAME)
 string(REPLACE "." "_" CONTENTS_NAME ${CONTENTS_NAME})
 string(TOUPPER ${CONTENTS_NAME} CONTENTS_NAME)
 
-file(READ ${SOURCE_FILE} CONTENTS)
+FILE(READ ${SOURCE_FILE} line_contents)
+
+# Replace double quotes with single quotes,
+# as double quotes will be used to wrap the lines
+STRING(REGEX REPLACE "\"" "'" line_contents "${line_contents}")
+
+# CMake separates list elements with semicolons, but semicolons
+# are used extensively in the shader code.
+# Replace with a temporary marker, to be reverted later.
+STRING(REGEX REPLACE ";" "{{SEMICOLON}}" line_contents "${line_contents}")
+
+# Make every line an individual element in the CMake list.
+STRING(REGEX REPLACE "\n" ";" line_contents "${line_contents}")
+
+# Build the shader string, wrapping each line in double quotes.
+foreach(line IN LISTS line_contents)
+    string(CONCAT CONTENTS "${CONTENTS}" \"${line}\\n\"\n)
+endforeach()
+
+# Revert the original semicolons in the source.
+STRING(REGEX REPLACE "{{SEMICOLON}}" ";" CONTENTS "${CONTENTS}")
 
 get_filename_component(OUTPUT_DIR ${HEADER_FILE} DIRECTORY)
 make_directory(${OUTPUT_DIR})

src/video_core/host_shaders/source_shader.h.in

@@ -4,6 +4,8 @@
 
 namespace HostShaders {
 
-constexpr std::string_view @CONTENTS_NAME@ = R"(@CONTENTS@)";
+constexpr std::string_view @CONTENTS_NAME@ = {
+@CONTENTS@
+};
 
 } // namespace HostShaders