[HLSL] Add RWBuffer::Load(Index) (llvm#117018)

This method is the same as `operator[]`, except that it returns a value
instead of a reference.

Author: bogner

clang/lib/Sema/HLSLExternalSemaSource.cpp

@@ -191,6 +191,19 @@ class BuiltinTypeDeclBuilder {
     return *this;
   }
 
+  BuiltinTypeDeclBuilder &addLoadMethods() {
+    if (Record->isCompleteDefinition())
+      return *this;
+
+    ASTContext &AST = Record->getASTContext();
+    IdentifierInfo &II = AST.Idents.get("Load", tok::TokenKind::identifier);
+    DeclarationName Load(&II);
+    // TODO: We also need versions with status for CheckAccessFullyMapped.
+    addHandleAccessFunction(Load, /*IsConst=*/false, /*IsRef=*/false);
+
+    return *this;
+  }
+
   FieldDecl *getResourceHandleField() {
     auto I = Fields.find("__handle");
     assert(I != Fields.end() &&
@@ -921,6 +934,7 @@ void HLSLExternalSemaSource::defineHLSLTypesWithForwardDeclarations() {
                     ResourceKind::TypedBuffer, /*IsROV=*/false,
                     /*RawBuffer=*/false)
         .addArraySubscriptOperators()
+        .addLoadMethods()
         .completeDefinition();
   });
 
@@ -933,6 +947,7 @@ void HLSLExternalSemaSource::defineHLSLTypesWithForwardDeclarations() {
                     ResourceKind::TypedBuffer, /*IsROV=*/true,
                     /*RawBuffer=*/false)
         .addArraySubscriptOperators()
+        .addLoadMethods()
         .completeDefinition();
   });
 

clang/test/AST/HLSL/TypedBuffers-AST.hlsl

@@ -87,6 +87,21 @@ RESOURCE<float> Buffer;
 // CHECK-NEXT: DeclRefExpr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> 'unsigned int' ParmVar 0x{{[0-9A-Fa-f]+}} 'Index' 'unsigned int'
 // CHECK-NEXT: AlwaysInlineAttr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> Implicit always_inline
 
+// CHECK-NEXT: CXXMethodDecl 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> <invalid sloc> Load 'element_type (unsigned int)'
+// CHECK-NEXT: ParmVarDecl 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> <invalid sloc> Index 'unsigned int'
+// CHECK-NEXT: CompoundStmt 0x{{[0-9A-Fa-f]+}} <<invalid sloc>>
+// CHECK-NEXT: ReturnStmt 0x{{[0-9A-Fa-f]+}} <<invalid sloc>>
+// CHECK-NEXT: UnaryOperator 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> 'element_type' prefix '*' cannot overflow
+// CHECK-NEXT: CallExpr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> 'element_type *'
+// CHECK-NEXT: DeclRefExpr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> '<builtin fn type>' Function 0x{{[0-9A-Fa-f]+}} '__builtin_hlsl_resource_getpointer' 'void (...) noexcept'
+// CHECK-NEXT: MemberExpr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> '__hlsl_resource_t
+// CHECK-SAME{LITERAL}: [[hlsl::resource_class(UAV)]]
+// CHECK-SAME{LITERAL}: [[hlsl::contained_type(element_type)]]
+// CHECK-SAME: ' lvalue .__handle 0x{{[0-9A-Fa-f]+}}
+// CHECK-NEXT: CXXThisExpr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> '[[RESOURCE]]<element_type>' lvalue implicit this
+// CHECK-NEXT: DeclRefExpr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> 'unsigned int' ParmVar 0x{{[0-9A-Fa-f]+}} 'Index' 'unsigned int'
+// CHECK-NEXT: AlwaysInlineAttr 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> Implicit always_inline
+
 // CHECK: ClassTemplateSpecializationDecl 0x{{[0-9A-Fa-f]+}} <<invalid sloc>> <invalid sloc> class [[RESOURCE]] definition
 
 // CHECK: TemplateArgument type 'float'

clang/test/CodeGenHLSL/builtins/RWBuffer-subscript.hlsl

@@ -6,9 +6,16 @@ RWBuffer<int> Out;
 [numthreads(1,1,1)]
 void main(unsigned GI : SV_GroupIndex) {
   // CHECK: define void @main()
+
   // CHECK: %[[INPTR:.*]] = call noundef nonnull align 4 dereferenceable(4) ptr @llvm.dx.resource.getpointer.p0.tdx.TypedBuffer_i32_1_0_1t(target("dx.TypedBuffer", i32, 1, 0, 1) %{{.*}}, i32 %{{.*}})
   // CHECK: %[[LOAD:.*]] = load i32, ptr %[[INPTR]]
   // CHECK: %[[OUTPTR:.*]] = call noundef nonnull align 4 dereferenceable(4) ptr @llvm.dx.resource.getpointer.p0.tdx.TypedBuffer_i32_1_0_1t(target("dx.TypedBuffer", i32, 1, 0, 1) %{{.*}}, i32 %{{.*}})
   // CHECK: store i32 %[[LOAD]], ptr %[[OUTPTR]]
   Out[GI] = In[GI];
+
+  // CHECK: %[[INPTR:.*]] = call ptr @llvm.dx.resource.getpointer.p0.tdx.TypedBuffer_i32_1_0_1t(target("dx.TypedBuffer", i32, 1, 0, 1) %{{.*}}, i32 %{{.*}})
+  // CHECK: %[[LOAD:.*]] = load i32, ptr %[[INPTR]]
+  // CHECK: %[[OUTPTR:.*]] = call noundef nonnull align 4 dereferenceable(4) ptr @llvm.dx.resource.getpointer.p0.tdx.TypedBuffer_i32_1_0_1t(target("dx.TypedBuffer", i32, 1, 0, 1) %{{.*}}, i32 %{{.*}})
+  // CHECK: store i32 %[[LOAD]], ptr %[[OUTPTR]]
+  Out[GI] = In.Load(GI);
 }