Add ability for intrinsics to require GLSL extensions

When cross-compiling, we need to detect when an intrinsic is used that required non-default GLSL capabilities and emit an appropriate `#extension ... : require` line.

I'm handling this by attaching a custom modifier to declarations that require an extension in order to be callable.

1 files changed, 11 insertions, 0 deletions

diff --git a/source/slang/parser.cpp b/source/slang/parser.cpp
index de63793b1..8314b0930 100644
--- a/source/slang/parser.cpp
+++ b/source/slang/parser.cpp
@@ -717,6 +717,17 @@ namespace Slang
                 AddModifier(&modifierLink, modifier);
             }
 
+            else if (AdvanceIf(parser, "__glsl_extension"))
+            {
+                auto modifier = new RequiredGLSLExtensionModifier();
+                modifier->Position = loc;
+
+                parser->ReadToken(TokenType::LParent);
+                modifier->extensionNameToken = parser->ReadToken(TokenType::Identifier);
+                parser->ReadToken(TokenType::RParent);
+
+                AddModifier(&modifierLink, modifier);
+            }
 
             else if (AdvanceIf(parser, "layout"))
             {