Fix intrinsic LoadLocalRootTableConstant for optix (#7949)

Due to an older version of spec referred there was an inconsitency v1.29
2/20/2025 - [HitObject LoadLocalRootArgumentsConstant]

Latest spec

https://microsoft.github.io/DirectX-Specs/d3d/Raytracing.html#hitobject-loadlocalroottableconstant

Refer:
OptiX backend support for Shader Execution Reordering (SER) features as
outlined in issue #6647. -

2 files changed, 29 insertions, 14 deletions

diff --git a/source/core/slang-platform.cpp b/source/core/slang-platform.cpp
index aab1f3044..f7e82fdf0 100644
--- a/source/core/slang-platform.cpp
+++ b/source/core/slang-platform.cpp
@@ -174,12 +174,27 @@ SLANG_COMPILE_TIME_ASSERT(E_OUTOFMEMORY == SLANG_E_OUT_OF_MEMORY);
 }
 
 #else // _WIN32
-
 /* static */ SlangResult PlatformUtil::getInstancePath([[maybe_unused]] StringBuilder& out)
 {
-    // On non Windows it's typically hard to get the instance path, so we'll say not implemented.
-    // The meaning is also somewhat more ambiguous - is it the exe or the shared library path?
+#if defined(__linux__) || defined(__CYGWIN__)
+    char path[PATH_MAX];
+    ssize_t len = readlink("/proc/self/exe", path, sizeof(path) - 1);
+    if (len == -1)
+    {
+        return SLANG_FAIL;
+    }
+
+    path[len] = '\0';
+    String pathString(path);
+
+    // We don't want the instance name, just the path to it
+    out.clear();
+    out.append(Path::getParentDirectory(pathString));
+
+    return out.getLength() > 0 ? SLANG_OK : SLANG_FAIL;
+#else
     return SLANG_E_NOT_IMPLEMENTED;
+#endif
 }
 
 /* static */ SlangResult PlatformUtil::appendResult(
diff --git a/source/slang/hlsl.meta.slang b/source/slang/hlsl.meta.slang
index c3d2efaac..2d9543716 100644
--- a/source/slang/hlsl.meta.slang
+++ b/source/slang/hlsl.meta.slang
@@ -20472,7 +20472,7 @@ struct HitObject
             __intrinsic_asm "($0 = NvMakeNop())";
         case glsl:
             __glslMakeNop(__return_val);
-        case cuda: __intrinsic_asm "optixMakeNopHitObject";
+        case cuda: __intrinsic_asm "slangOptixMakeNopHitObject";
         case spirv:
             spirv_asm 
             {
@@ -20561,7 +20561,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".IsMiss";
         case glsl: __intrinsic_asm "hitObjectIsMissNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectIsMiss";
+        case cuda: __intrinsic_asm "slangOptixHitObjectIsMiss";
         case spirv:
             return spirv_asm 
             {
@@ -20582,7 +20582,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".IsHit";
         case glsl: __intrinsic_asm "hitObjectIsHitNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectIsHit";
+        case cuda: __intrinsic_asm "slangOptixHitObjectIsHit";
         case spirv: 
             return spirv_asm 
             {
@@ -20603,7 +20603,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".IsNop";
         case glsl: __intrinsic_asm "hitObjectIsEmptyNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectIsNop";
+        case cuda: __intrinsic_asm "slangOptixHitObjectIsNop";
         case spirv: 
             return spirv_asm 
             {
@@ -20655,7 +20655,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".GetShaderTableIndex";
         case glsl: __intrinsic_asm "hitObjectGetShaderBindingTableRecordIndexNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectGetSbtRecordIndex";
+        case cuda: __intrinsic_asm "slangOptixHitObjectGetSbtRecordIndex";
         case spirv: 
             return spirv_asm 
             {
@@ -20675,7 +20675,7 @@ struct HitObject
         __target_switch
         {
         case hlsl: __intrinsic_asm ".SetShaderTableIndex";
-        case cuda: __intrinsic_asm "optixHitObjectSetSbtRecordIndex";
+        case cuda: __intrinsic_asm "slangOptixHitObjectSetSbtRecordIndex";
         }
     }
         /// Returns the instance index of a hit. Valid if the hit object represents a hit.
@@ -20689,7 +20689,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".GetInstanceIndex";
         case glsl: __intrinsic_asm "hitObjectGetInstanceIdNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectGetInstanceIndex";
+        case cuda: __intrinsic_asm "slangOptixHitObjectGetInstanceIndex";
         case spirv: 
             return spirv_asm 
             {
@@ -20711,7 +20711,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".GetInstanceID";
         case glsl: __intrinsic_asm "hitObjectGetInstanceCustomIndexNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectGetInstanceId";
+        case cuda: __intrinsic_asm "slangOptixHitObjectGetInstanceId";
         case spirv:
             return spirv_asm 
             {
@@ -20733,7 +20733,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".GetGeometryIndex";
         case glsl: __intrinsic_asm "hitObjectGetGeometryIndexNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectGetSbtGASIndex";
+        case cuda: __intrinsic_asm "slangOptixHitObjectGetSbtGASIndex";
         case spirv: 
             return spirv_asm 
             {
@@ -20755,7 +20755,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".GetPrimitiveIndex";
         case glsl: __intrinsic_asm "hitObjectGetPrimitiveIndexNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectGetPrimitiveIndex";
+        case cuda: __intrinsic_asm "slangOptixHitObjectGetPrimitiveIndex";
         case spirv: 
             return spirv_asm 
             {
@@ -20799,7 +20799,7 @@ struct HitObject
         {
         case hlsl: __intrinsic_asm ".GetClusterID";
         case glsl: __intrinsic_asm "hitObjectGetClusterIdNV($0)";
-        case cuda: __intrinsic_asm "optixHitObjectGetClusterId";
+        case cuda: __intrinsic_asm "slangOptixHitObjectGetClusterId";
         case spirv:
             return spirv_asm
             {