GLSL SSBO Support (#3400)

* Squash warnings and fix build with SLANG_EMBED_STDLIB

* Add GLSLShaderStorageBuffer magic wrapper

* Make GLSLSSBO not a uniform type

* Buffers are global variables

* Allow creating ssbo aggregate types

* Allow reading from RWSB using builder

* Nicer debug printing for ssbos

* Lower SSBO to RWSB

* Parse interface blocks into wrapped structs

* Lower Interface Block Decls to structs

* remove comment

* Two simple ssbo tests

* Move ssbo pass earlier

* Correct mutable buffer detection

* Do not replace ssbo usages outside of blocks

* Treat GLSLSSBO as a mutable buffer for type layouts

* regenerate vs projects

* Correctly detect ssbo types

* Diagnose illegal ssbo

* remove unreachable code

* neaten

* ci wobble

* Make GLSLSSBO ast handling more uniform

* Add modifier cases for glsl

* Use empty val info for unhandled interface blocks

necessary for ./tests/glsl/out-binding-redeclaration.slang

* more sophisticated modifier check

* Correct ssbo wrapper name

1 files changed, 15 insertions, 6 deletions

diff --git a/source/slang/slang-check-modifier.cpp b/source/slang/slang-check-modifier.cpp
index a9a8c19da..c9800b325 100644
--- a/source/slang/slang-check-modifier.cpp
+++ b/source/slang/slang-check-modifier.cpp
@@ -999,16 +999,15 @@ namespace Slang
         }
     }
 
-    bool isModifierAllowedOnDecl(ASTNodeType modifierType, Decl* decl)
+    bool isModifierAllowedOnDecl(bool isGLSLInput, ASTNodeType modifierType, Decl* decl)
     {
         switch (modifierType)
         {
-            // Allowed only on parameters and global variables.
+            // In addition to the above cases, these are also present on empty
+            // global declarations, for instance
+            // layout(local_size_x=1) in;
         case ASTNodeType::InModifier:
-        case ASTNodeType::OutModifier:
         case ASTNodeType::InOutModifier:
-        case ASTNodeType::RefModifier:
-        case ASTNodeType::ConstRefModifier:
         case ASTNodeType::GLSLLayoutModifier:
         case ASTNodeType::GLSLParsedLayoutModifier:
         case ASTNodeType::GLSLConstantIDLayoutModifier:
@@ -1017,6 +1016,16 @@ namespace Slang
         case ASTNodeType::GLSLLayoutModifierGroupMarker:
         case ASTNodeType::GLSLLayoutModifierGroupBegin:
         case ASTNodeType::GLSLLayoutModifierGroupEnd:
+            // If we are in GLSL mode, also allow these but otherwise fall to
+            // the regular check
+            if(isGLSLInput && as<EmptyDecl>(decl) && isGlobalDecl(decl))
+                return true;
+            [[fallthrough]];
+
+            // Allowed only on parameters and global variables.
+        case ASTNodeType::OutModifier:
+        case ASTNodeType::RefModifier:
+        case ASTNodeType::ConstRefModifier:
         case ASTNodeType::GLSLBufferModifier:
         case ASTNodeType::GLSLWriteOnlyModifier:
         case ASTNodeType::GLSLReadOnlyModifier:
@@ -1114,7 +1123,7 @@ namespace Slang
 
         if (auto decl = as<Decl>(syntaxNode))
         {
-            if (!isModifierAllowedOnDecl(m->astNodeType, decl))
+            if (!isModifierAllowedOnDecl(getLinkage()->getAllowGLSLInput(), m->astNodeType, decl))
             {
                 getSink()->diagnose(m, Diagnostics::modifierNotAllowed, m);
                 return m;