Support derivative functions in compute & capabilities adjustments (#4014)

* Support derivative functions in compute & capabilities adjustments

fixes #4000

PR implements derivative functions in compute shaders properly so we have the functionality for SPIR-V & GLSL. Tests reflect fragment and compute paths.

PR also adjusts capabilities to correct wrong SPRI-V target capabilities for when using textures.

Remarks:
1. __requireComputeDerivative(); is a intrinsic_op and not modifier since inlining will destroy the modifier.
2. Derivative mode is tied to an entry point decoration `[DerivativeGroupQuad]`/`[DerivativeGroupLinear]` or GLSL syntax ``derivative_group_linearNV`. Default is to set the mode to `[DerivativeGroupQuad]`

* remove -emit-spirv-directly

* fixes

1. fix minor issue fwidth change where I returned the wrong type
2. fix issue where glslang{glsl->spirv} is wrong, so we don't run that test and just run the glsl test & direct spir-v test for intrinsic-texture.slang

* adjust as per review and refine code

1. add test to ensure multi-diverging-in-logic entry points work -- 2 functions which may cause computeDerivatives + 1 that uses, 1 that does not.
2. naming
3. use entry point ref graph for c-like-targets
4. reordered some code to util's and removed `static linline` since that was just for ease of coding on my end (should not have been pushed).

* Grammer

* split up source file + issolate GLSL emit path change.

---------

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/source/slang/slang-parser.cpp b/source/slang/slang-parser.cpp
index e0b964a45..23ee5e29d 100644
--- a/source/slang/slang-parser.cpp
+++ b/source/slang/slang-parser.cpp
@@ -8036,6 +8036,8 @@ namespace Slang
         ModifierListBuilder listBuilder;
 
         GLSLLayoutLocalSizeAttribute* numThreadsAttrib = nullptr;
+        GLSLLayoutDerivativeGroupQuadAttribute* derivativeGroupQuadAttrib = nullptr;
+        GLSLLayoutDerivativeGroupLinearAttribute* derivativeGroupLinearAttrib = nullptr; 
 
         ImageFormat format;
 
@@ -8082,6 +8084,14 @@ namespace Slang
                     numThreadsAttrib->args[localSizeIndex] = expr;
                 }
             }
+            else if (nameText == "derivative_group_quadsNV")
+            {
+                derivativeGroupQuadAttrib = parser->astBuilder->create<GLSLLayoutDerivativeGroupQuadAttribute>();
+            }
+            else if (nameText == "derivative_group_linearNV")
+            {
+                derivativeGroupLinearAttrib = parser->astBuilder->create<GLSLLayoutDerivativeGroupLinearAttribute>();
+            }
             else if (nameText == "binding" ||
                 nameText == "set")
             {
@@ -8189,9 +8199,11 @@ namespace Slang
 #undef CASE
 
         if (numThreadsAttrib)
-        {
             listBuilder.add(numThreadsAttrib);
-        }
+        if(derivativeGroupQuadAttrib)
+            listBuilder.add(derivativeGroupQuadAttrib);
+        if(derivativeGroupLinearAttrib)
+            listBuilder.add(derivativeGroupLinearAttrib);
 
         listBuilder.add(parser->astBuilder->create<GLSLLayoutModifierGroupEnd>());