transform/shader_io: Generate a wrapper function
This is a major reworking of this transform. The old transform code
was getting unwieldy, with part of the complication coming from the
handling of multiple return statements. By generating a wrapper
function instead, we can avoid a lot of this complexity.
The original entry point function is stripped of all shader IO
attributes (as well as `stage` and `workgroup_size`), but the body is
left unmodified. A new entry point wrapper function is introduced
which calls the original function, packing/unpacking the shader inputs
as necessary, and propagates the result to the corresponding shader
outputs.
The new code has been refactored to use a state object with the
different parts of the transform split into separate functions, which
makes it much more manageable.
Fixed: tint:1076
Bug: tint:920
Change-Id: I3490a0ea7a3509a4e198ce730e476516649d8d96
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/60521
Auto-Submit: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
diff --git a/test/shader_io/fragment_output_locations_struct.wgsl.expected.hlsl b/test/shader_io/fragment_output_locations_struct.wgsl.expected.hlsl
index 460f4a3..09216c3 100644
--- a/test/shader_io/fragment_output_locations_struct.wgsl.expected.hlsl
+++ b/test/shader_io/fragment_output_locations_struct.wgsl.expected.hlsl
@@ -11,8 +11,17 @@
float4 loc3 : SV_Target3;
};
-tint_symbol main() {
+FragmentOutputs main_inner() {
const FragmentOutputs tint_symbol_1 = {1, 1u, 1.0f, float4(1.0f, 2.0f, 3.0f, 4.0f)};
- const tint_symbol tint_symbol_2 = {tint_symbol_1.loc0, tint_symbol_1.loc1, tint_symbol_1.loc2, tint_symbol_1.loc3};
- return tint_symbol_2;
+ return tint_symbol_1;
+}
+
+tint_symbol main() {
+ const FragmentOutputs inner_result = main_inner();
+ tint_symbol wrapper_result = (tint_symbol)0;
+ wrapper_result.loc0 = inner_result.loc0;
+ wrapper_result.loc1 = inner_result.loc1;
+ wrapper_result.loc2 = inner_result.loc2;
+ wrapper_result.loc3 = inner_result.loc3;
+ return wrapper_result;
}
