From 12f7237e4060388494c549623f4a640327b7ca08 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Tue, 14 Nov 2023 17:46:05 -0800
Subject: Add GLSL Compatibility. (#3321)

* Parse glsl buffer blocks to GLSLInterfaceBlockDecl

* Parse glsl local size layout declarations

* Parse (and ignore) glsl version directives

* spelling

* Better l-value interpretation for glsl interface blocks

* Better l-value interpretation for glsl interface blocks

* Add compile flag for enabling glsl

* Parse and ignore precision modifiers.

* Automatically import `glsl` module for compatiblity.

* Complete vector and matrix types for glsl

* Remove generated file from repo

* Bump .gitignore

* do not mark out globals as params

* Synthesize entrypoint layout from global inout vars.

* update test result.

* Allow HLSL semantic on global variables.

* Fix.

* Fix test.

* Fix win32 compile error.

* Add more builtin input/output and texture intrinsics.

* Add struct/array constructor syntax.

* Skip `#extension` lines.

* overide operator * for matrix/vector multiplication.

* Add `matrixCompMult`.

* Parse modifiers in for loop init var declr.

* Add more glsl intrinsics, add stage into to var layout.

* Allow `int[3] x` syntax.

* Fix array type syntax.

---------

Co-authored-by: Ellie Hermaszewska <ellieh@nvidia.com>
Co-authored-by: Yong He <yhe@nvidia.com>
---
 source/slang/slang-check-expr.cpp | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

(limited to 'source/slang/slang-check-expr.cpp')

diff --git a/source/slang/slang-check-expr.cpp b/source/slang/slang-check-expr.cpp
index 2f8b28afc..e130275bb 100644
--- a/source/slang/slang-check-expr.cpp
+++ b/source/slang/slang-check-expr.cpp
@@ -269,6 +269,25 @@ namespace Slang
         }
     }
 
+    static bool isMutableGLSLBufferBlockVarExpr(Expr* expr)
+    {
+        if(const auto varExpr = as<VarExpr>(expr))
+        {
+            if(const auto declRefType = as<DeclRefType>(varExpr->type->getCanonicalType()))
+            {
+                if(declRefType->getDeclRef().getDecl()->isDerivedFrom(ASTNodeType::GLSLInterfaceBlockDecl))
+                {
+                    const auto d = varExpr->declRef.getDecl();
+                    if(d->hasModifier<GLSLBufferModifier>() && !d->hasModifier<GLSLReadOnlyModifier>())
+                    {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
     DeclRefExpr* SemanticsVisitor::ConstructDeclRefExpr(
         DeclRef<Decl>   declRef,
         Expr*    baseExpr,
@@ -370,7 +389,10 @@ namespace Slang
                 // l-value status of the base expression into account now.
                 if(!baseExpr->type.isLeftValue)
                 {
-                    expr->type.isLeftValue = false;
+                    // One exception to this is if we're reading the contents
+                    // of a GLSL buffer interface block which isn't marked as
+                    // read_only
+                    expr->type.isLeftValue = isMutableGLSLBufferBlockVarExpr(baseExpr);
                 }
                 else
                 {
-- 
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