Allow HLSLDecls in dependent DeclContexts (#4114)

Summary of the changes:
- Error for dependent context decl (template decl) now only occurs when templates are not enabled
- Amended faulty test cases revealed by bug fix (tools\clang\test\HLSLFileCheck\hlsl\payload_qualifier\combination.hlsl, tools\clang\test\HLSLFileCheck\hlsl\template\InstantiateHLSLAttributes.hlsl, tools\clang\test\HLSLFileCheck\hlsl\template\missing_typename.hlsl)
- Added test case to reflect bug fix
(tools\clang\test\HLSLFileCheck\hlsl\template\3731-resource-descriptor-heap.hlsl)

Attribution:
Chris Bieneman
Timothy Corringham
Samantha Del Rosario

Co-authored-by: sam-sam98 <[email protected]>

Author: 2 people

tools/clang/lib/Sema/SemaHLSL.cpp

@@ -12425,12 +12425,11 @@ bool Sema::DiagnoseHLSLDecl(Declarator &D, DeclContext *DC, Expr *BitWidth,
   assert(getLangOpts().HLSL &&
          "otherwise this is called without checking language first");
 
-  // NOTE: some tests may declare templates.
-  if (DC->isDependentContext()) return true;
+  // If we have a template declaration but haven't enabled templates, error.
+  if (DC->isDependentContext() && !getLangOpts().EnableTemplates) return false;
 
   DeclSpec::SCS storage = D.getDeclSpec().getStorageClassSpec();
   assert(!DC->isClosure() && "otherwise parser accepted closure syntax instead of failing with a syntax error");
-  assert(!DC->isDependentContext() && "otherwise parser accepted a template instead of failing with a syntax error");
 
   bool result = true;
   bool isTypedef = storage == DeclSpec::SCS_typedef;

tools/clang/test/HLSLFileCheck/hlsl/payload_qualifier/combination.hlsl

@@ -1,4 +1,5 @@
 // RUN: %dxc -T lib_6_6 %s -enable-payload-qualifiers | FileCheck %s
+// RUN: %dxc -T lib_6_6 %s -enable-payload-qualifiers -enable-templates -DTEMPLATES | FileCheck %s
 
 // CHECK: error: field 'x1' is qualified 'read' for shader stage 'miss' but has no valid producer
 // CHECK: error: field 'x2' is qualified 'read' for shader stage 'closesthit' but has no valid producer
@@ -247,9 +248,15 @@
 // CHECK: error: field 'x246' is qualified 'write' for shader stage 'miss' but has no valid consumer
 // CHECK: error: field 'x246' is qualified 'write' for shader stage 'closesthit' but has no valid consumer
 // CHECK: error: field 'x247' is qualified 'write' for shader stage 'miss' but has no valid consumer
-// CHECK: error: field 'x247' is qualified 'write' for shader stage 'closesthit' but has no valid consumer
+// CHECK: error: field 'x247' is qualified 'write' for shader stage 'closesthit'
+// but has no valid consumer
+#ifdef TEMPLATES
+template<typename I>
+#else
+#define I int
+#endif
 struct [payload] MyPayload {
-int x0 : read();
+I x0 : read();
 int x1 : read(miss);
 int x2 : read(closesthit);
 int x3 : read(miss, closesthit);

tools/clang/test/HLSLFileCheck/hlsl/template/3731-resource-descriptor-heap.hlsl

@@ -0,0 +1,36 @@
+// RUN: %dxc -T cs_6_6 -E main -enable-templates -ast-dump %s | FileCheck %s
+// RUN: %dxc -T cs_6_6 -E main -HV 2021 -ast-dump %s | FileCheck %s
+
+struct SimpleBuffer {
+  uint handle;
+
+  template<typename T>
+  T Load() {
+    ByteAddressBuffer buf = ResourceDescriptorHeap[handle];
+    return buf.Load<T>(0);
+  }
+};
+
+[numthreads(1,1,1)]
+void main() {
+  SimpleBuffer b = (SimpleBuffer)0;
+  b.Load<uint>();
+}
+
+// CHECK:      CXXOperatorCallExpr 0x{{[0-9a-fA-F]+}} <col:29, col:58> 'const .Resource'
+// CHECK-NEXT: ImplicitCastExpr 0x{{[0-9a-fA-F]+}} <col:51, col:58> 'const .Resource (*)(unsigned int) const' <FunctionToPointerDecay>
+// CHECK-NEXT: DeclRefExpr 0x{{[0-9a-fA-F]+}} <col:51, col:58> 'const .Resource (unsigned int) const' lvalue CXXMethod 0x{{[0-9a-fA-F]+}} 'operator[]' 'const .Resource (unsigned int) const'
+// CHECK-NEXT: ImplicitCastExpr 0x{{[0-9a-fA-F]+}} <col:29> 'const .Resource' lvalue <NoOp>
+// CHECK-NEXT: DeclRefExpr 0x{{[0-9a-fA-F]+}} <col:29> '.Resource' lvalue Var 0x{{[0-9a-fA-F]+}} 'ResourceDescriptorHeap' '.Resource'
+// CHECK-NEXT: ImplicitCastExpr 0x{{[0-9a-fA-F]+}} <col:52> 'uint':'unsigned int' <LValueToRValue>
+// CHECK-NEXT: MemberExpr 0x{{[0-9a-fA-F]+}} <col:52> 'uint':'unsigned int' lvalue ->handle
+// CHECK-NEXT: CXXThisExpr 0x{{[0-9a-fA-F]+}} <col:52> 'SimpleBuffer
+
+// CHECK:      CXXOperatorCallExpr 0x{{[0-9a-fA-F]+}} <col:29, col:58> 'const .Resource'
+// CHECK-NEXT: ImplicitCastExpr 0x{{[0-9a-fA-F]+}} <col:51, col:58> 'const .Resource (*)(unsigned int) const' <FunctionToPointerDecay>
+// CHECK-NEXT: DeclRefExpr 0x{{[0-9a-fA-F]+}} <col:51, col:58> 'const .Resource (unsigned int) const' lvalue CXXMethod 0x{{[0-9a-fA-F]+}} 'operator[]' 'const .Resource (unsigned int) const'
+// CHECK-NEXT: ImplicitCastExpr 0x{{[0-9a-fA-F]+}} <col:29> 'const .Resource' lvalue <NoOp>
+// CHECK-NEXT: DeclRefExpr 0x{{[0-9a-fA-F]+}} <col:29> '.Resource' lvalue Var 0x{{[0-9a-fA-F]+}} 'ResourceDescriptorHeap' '.Resource'
+// CHECK-NEXT: ImplicitCastExpr 0x{{[0-9a-fA-F]+}} <col:52> 'uint':'unsigned int' <LValueToRValue>
+// CHECK-NEXT: MemberExpr 0x{{[0-9a-fA-F]+}} <col:52> 'uint':'unsigned int' lvalue ->handle
+// CHECK-NEXT: CXXThisExpr 0x{{[0-9a-fA-F]+}} <col:52> 'SimpleBuffer