[HLSL] Add internal linkage attribute to resources

[hekota]

HLSL resources should not be externally visible from the module. We made sure of this by marking them static as soon as they were declared. However, this prevents us fixing issue #166458 because there is no way to know if a resource has been explicitly marked static by the user, and can therefore be assigned to.

This change moves from making all resources static to adding Clang internal linkage attribute to all non-static resource declarations as a global scope.

No explicit test added this change. There is a number of existing HLSL codegen tests that already verify that the resource globals are emitted as internal global.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-hlsl

Author: Helena Kotas (hekota)

Changes

HLSL resources should not be externally visible from the module. We made sure of this by marking them static as soon as they were declared. However, this prevents us fixing issue #166458 because there is no way to know if a resource has been explicitly marked static by the user, and can therefore be assigned to.

This change is moves from making all resources static to adding Clang internal linkage attribute to all non-static resource declarations as a global scope.

No explicit test added this change. There is a number of existing HLSL codegen tests that already verify that the resource globals are emitted as internal global.

---

Full diff: https://github.com/llvm/llvm-project/pull/166844.diff

3 Files Affected:

• (modified) clang/lib/Sema/SemaHLSL.cpp (+8-5)
• (modified) clang/test/AST/HLSL/cbuffer.hlsl (+1-1)
• (modified) clang/test/AST/HLSL/private.hlsl (+1-1)

diff --git a/clang/lib/Sema/SemaHLSL.cpp b/clang/lib/Sema/SemaHLSL.cpp
index a06c57b15c585..e95fe16e6cb6c 100644
--- a/clang/lib/Sema/SemaHLSL.cpp
+++ b/clang/lib/Sema/SemaHLSL.cpp
@@ -3910,12 +3910,15 @@ void SemaHLSL::ActOnVariableDeclarator(VarDecl *VD) {
     if (VD->getType()->isHLSLIntangibleType())
       collectResourceBindingsOnVarDecl(VD);
 
-    if (isResourceRecordTypeOrArrayOf(VD) ||
-        VD->hasAttr<HLSLVkConstantIdAttr>()) {
-      // Make the variable for resources static. The global externally visible
-      // storage is accessed through the handle, which is a member. The variable
-      // itself is not externally visible.
+    if (VD->hasAttr<HLSLVkConstantIdAttr>())
       VD->setStorageClass(StorageClass::SC_Static);
+
+    if (isResourceRecordTypeOrArrayOf(VD) &&
+        VD->getStorageClass() != SC_Static) {
+      // Add internal linkage attribute to non-static resource variables. The
+      // global externally visible storage is accessed through the handle, which
+      // is a member. The variable itself is not externally visible.
+      VD->addAttr(InternalLinkageAttr::CreateImplicit(getASTContext()));
     }
 
     // process explicit bindings
diff --git a/clang/test/AST/HLSL/cbuffer.hlsl b/clang/test/AST/HLSL/cbuffer.hlsl
index f3c6636232798..b0b5b989e36c2 100644
--- a/clang/test/AST/HLSL/cbuffer.hlsl
+++ b/clang/test/AST/HLSL/cbuffer.hlsl
@@ -153,7 +153,7 @@ cbuffer CB {
   static float SV;
   // CHECK: VarDecl {{.*}} s7 'EmptyStruct' callinit
   EmptyStruct s7;
-  // CHECK: VarDecl {{.*}} Buf 'RWBuffer<float>':'hlsl::RWBuffer<float>' static callinit
+  // CHECK: VarDecl {{.*}} Buf 'RWBuffer<float>':'hlsl::RWBuffer<float>' callinit
   RWBuffer<float> Buf;
   // CHECK: VarDecl {{.*}} ea 'EmptyArrayTypedef':'float[10][0]'
   EmptyArrayTypedef ea;
diff --git a/clang/test/AST/HLSL/private.hlsl b/clang/test/AST/HLSL/private.hlsl
index e00afb8f5cbd8..ba7380ec3cfda 100644
--- a/clang/test/AST/HLSL/private.hlsl
+++ b/clang/test/AST/HLSL/private.hlsl
@@ -3,7 +3,7 @@
 // CHECK: VarDecl {{.*}} global_scalar 'hlsl_private int' static cinit
 static int global_scalar = 0;
 
-// CHECK: VarDecl {{.*}} global_buffer 'RWBuffer<float>':'hlsl::RWBuffer<float>' static callinit
+// CHECK: VarDecl {{.*}} global_buffer 'RWBuffer<float>':'hlsl::RWBuffer<float>' callinit
 RWBuffer<float> global_buffer;
 
 class A {