Fix several issues discovered by Falcor (#467)

Fixes #466

Most of these are Vulkan-related regressions.

* Kludge the definition of `GroupMemoryBarrierWithGroupSync()` for GLSL so that it works around parentheses that the emit logic now introduces.

* Don't emit `static` for global constants when targetting GLSL

* Emit the `flat` modifier for varying input/output with integer type, when targetting GLSL

* Avoid checking parameter default-value expressions more than once, because this can crash when the checking introduces syntax that is not expected to appear in the input AST

1 files changed, 10 insertions, 2 deletions

diff --git a/source/slang/check.cpp b/source/slang/check.cpp
index b1df71428..eb15d0889 100644
--- a/source/slang/check.cpp
+++ b/source/slang/check.cpp
@@ -511,7 +511,11 @@ namespace Slang
 
             // Use visitor pattern to dispatch to correct case
             DeclVisitor::dispatch(decl);
-            decl->SetCheckState(state);
+
+            if(state > decl->checkState)
+            {
+                decl->SetCheckState(state);
+            }
         }
 
         void EnusreAllDeclsRec(RefPtr<Decl> decl)
@@ -2839,6 +2843,8 @@ namespace Slang
                 paramDecl->type = typeExpr;
             }
 
+            paramDecl->SetCheckState(DeclCheckState::CheckedHeader);
+
             // The "initializer" expression for a parameter represents
             // a default argument value to use if an explicit one is
             // not supplied.
@@ -2857,6 +2863,8 @@ namespace Slang
                 // to other parameters of the same function (or maybe
                 // only the parameters to its left...).
             }
+
+            paramDecl->SetCheckState(DeclCheckState::Checked);
         }
 
         void VisitFunctionDeclaration(FuncDecl *functionNode)
@@ -2870,7 +2878,7 @@ namespace Slang
             HashSet<Name*> paraNames;
             for (auto & para : functionNode->GetParameters())
             {
-                checkDecl(para);
+                EnsureDecl(para, DeclCheckState::CheckedHeader);
 
                 if (paraNames.Contains(para->getName()))
                 {