[HLSL] Add Buffer def to frontend #141086

V-FEXrt · 2025-05-22T15:26:11Z

Fixes #138902

Defines the Buffer<> type in the clang frontend. Lowering from IR->Target Machine is already handled by other code

llvmbot · 2025-05-22T15:26:46Z

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-hlsl

Author: Ashley Coleman (V-FEXrt)

Changes

Fixes #138902

Defines the Buffer<> type in the clang frontend. Lowering from IR->Target Machine is already handled by other code

Full diff: https://github.com/llvm/llvm-project/pull/141086.diff

4 Files Affected:

(modified) clang/lib/Sema/HLSLExternalSemaSource.cpp (+13)
(added) clang/test/SemaHLSL/BuiltIns/Buffers.hlsl (+114)
(modified) clang/test/SemaHLSL/BuiltIns/RWBuffers.hlsl (+2-2)
(modified) clang/test/SemaHLSL/BuiltIns/StructuredBuffers.hlsl (+2-2)

diff --git a/clang/lib/Sema/HLSLExternalSemaSource.cpp b/clang/lib/Sema/HLSLExternalSemaSource.cpp
index 38bde7c28e946..726581d131623 100644
--- a/clang/lib/Sema/HLSLExternalSemaSource.cpp
+++ b/clang/lib/Sema/HLSLExternalSemaSource.cpp
@@ -266,6 +266,19 @@ void HLSLExternalSemaSource::defineHLSLTypesWithForwardDeclarations() {
       *SemaPtr, HLSLNamespace, /*isTypedBuffer*/ true);
   ConceptDecl *StructuredBufferConcept = constructBufferConceptDecl(
       *SemaPtr, HLSLNamespace, /*isTypedBuffer*/ false);
+
+  Decl = BuiltinTypeDeclBuilder(*SemaPtr, HLSLNamespace, "Buffer")
+             .addSimpleTemplateParams({"element_type"}, TypedBufferConcept)
+             .finalizeForwardDeclaration();
+
+  onCompletion(Decl, [this](CXXRecordDecl *Decl) {
+    setupBufferType(Decl, *SemaPtr, ResourceClass::SRV, /*IsROV=*/false,
+                    /*RawBuffer=*/false)
+        .addArraySubscriptOperators()
+        .addLoadMethods()
+        .completeDefinition();
+  });
+
   Decl = BuiltinTypeDeclBuilder(*SemaPtr, HLSLNamespace, "RWBuffer")
              .addSimpleTemplateParams({"element_type"}, TypedBufferConcept)
              .finalizeForwardDeclaration();
diff --git a/clang/test/SemaHLSL/BuiltIns/Buffers.hlsl b/clang/test/SemaHLSL/BuiltIns/Buffers.hlsl
new file mode 100644
index 0000000000000..477a16a454a9c
--- /dev/null
+++ b/clang/test/SemaHLSL/BuiltIns/Buffers.hlsl
@@ -0,0 +1,114 @@
+// RUN: %clang_cc1 -Wno-hlsl-implicit-binding -triple dxil-pc-shadermodel6.0-compute -x hlsl -fsyntax-only -verify %s
+
+typedef vector<float, 3> float3;
+typedef vector<double, 2> double2;
+typedef vector<double, 3> double3;
+
+
+// expected-error@+1 {{class template 'Buffer' requires template arguments}}
+Buffer BufferErr1;
+
+// expected-error@+1 {{too few template arguments for class template 'Buffer'}}
+Buffer<> BufferErr2;
+
+// test implicit Buffer concept
+Buffer<int> r1;
+Buffer<float> r2;
+Buffer<float3> Buff;
+Buffer<double2> r4;
+
+// expected-error@+4 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{template declaration from hidden source: template <typename element_type> requires __is_typed_resource_element_compatible<element_type> class Buffer}}
+// expected-note@*:* {{because 'hlsl::Buffer<int>' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(hlsl::Buffer<int>)' evaluated to false}}
+Buffer<Buffer<int> > r5;
+
+struct s {
+    int x;
+};
+
+struct Empty {};
+
+template<typename T> struct TemplatedBuffer {
+    T a;
+};
+
+template<typename T> struct TemplatedVector {
+    vector<T, 4> v;
+};
+
+// structs not allowed
+// expected-error@+4 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{template declaration from hidden source: template <typename element_type> requires __is_typed_resource_element_compatible<element_type> class Buffer}}
+// expected-note@*:* {{because 's' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(s)' evaluated to false}}
+Buffer<s> r6;
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'Empty' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(Empty)' evaluated to false}}
+Buffer<Empty> r7;
+
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'TemplatedBuffer<int>' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(TemplatedBuffer<int>)' evaluated to false}}
+Buffer<TemplatedBuffer<int> > r8;
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'TemplatedVector<int>' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(TemplatedVector<int>)' evaluated to false}}
+Buffer<TemplatedVector<int> > r9;
+
+// arrays not allowed
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'half[4]' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(half[4])' evaluated to false}}
+Buffer<half[4]> r10;
+
+typedef vector<int, 8> int8;
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'vector<int, 8>' (vector of 8 'int' values) does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(vector<int, 8>)' evaluated to false}}
+Buffer<int8> r11;
+
+typedef int MyInt;
+Buffer<MyInt> r12;
+
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'bool' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(bool)' evaluated to false}}
+Buffer<bool> r13;
+
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'vector<bool, 2>' (vector of 2 'bool' values) does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(vector<bool, 2>)' evaluated to false}}
+Buffer<vector<bool, 2>> r14;
+
+enum numbers { one, two, three };
+
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'numbers' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(numbers)' evaluated to false}}
+Buffer<numbers> r15;
+
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'vector<double, 3>' (vector of 3 'double' values) does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(vector<double, 3>)' evaluated to false}}
+Buffer<double3> r16;
+
+
+struct threeDoubles {
+  double a;
+  double b;
+  double c;
+};
+
+// expected-error@+3 {{constraints not satisfied for class template 'Buffer'}}
+// expected-note@*:* {{because 'threeDoubles' does not satisfy '__is_typed_resource_element_compatible'}}
+// expected-note@*:* {{because '__builtin_hlsl_is_typed_resource_element_compatible(threeDoubles)' evaluated to false}}
+Buffer<threeDoubles> BufferErr3;
+
+
+[numthreads(1,1,1)]
+void main() {
+  (void)Buff.__handle; // expected-error {{'__handle' is a private member of 'hlsl::Buffer<vector<float, 3>>'}}
+  // expected-note@* {{implicitly declared private here}}
+}
diff --git a/clang/test/SemaHLSL/BuiltIns/RWBuffers.hlsl b/clang/test/SemaHLSL/BuiltIns/RWBuffers.hlsl
index 91e96b995585f..b4f59393a1768 100644
--- a/clang/test/SemaHLSL/BuiltIns/RWBuffers.hlsl
+++ b/clang/test/SemaHLSL/BuiltIns/RWBuffers.hlsl
@@ -14,7 +14,7 @@ RWBuffer<> BufferErr2;
 // test implicit RWBuffer concept
 RWBuffer<int> r1;
 RWBuffer<float> r2;
-RWBuffer<float3> Buffer;
+RWBuffer<float3> Buff;
 RWBuffer<double2> r4;
 
 // expected-error@+4 {{constraints not satisfied for class template 'RWBuffer'}}
@@ -109,6 +109,6 @@ RWBuffer<threeDoubles> BufferErr3;
 
 [numthreads(1,1,1)]
 void main() {
-  (void)Buffer.__handle; // expected-error {{'__handle' is a private member of 'hlsl::RWBuffer<vector<float, 3>>'}}
+  (void)Buff.__handle; // expected-error {{'__handle' is a private member of 'hlsl::RWBuffer<vector<float, 3>>'}}
   // expected-note@* {{implicitly declared private here}}
 }
diff --git a/clang/test/SemaHLSL/BuiltIns/StructuredBuffers.hlsl b/clang/test/SemaHLSL/BuiltIns/StructuredBuffers.hlsl
index 991b04c80ac86..6596f73b25170 100644
--- a/clang/test/SemaHLSL/BuiltIns/StructuredBuffers.hlsl
+++ b/clang/test/SemaHLSL/BuiltIns/StructuredBuffers.hlsl
@@ -2,7 +2,7 @@
 
 typedef vector<float, 3> float3;
 
-StructuredBuffer<float3> Buffer;
+StructuredBuffer<float3> Buff;
 
 // expected-error@+2 {{class template 'StructuredBuffer' requires template arguments}}
 // expected-note@*:* {{template declaration from hidden source: template <typename element_type> requires __is_structured_resource_element_compatible<element_type> class StructuredBuffer {}}}
@@ -26,6 +26,6 @@ StructuredBuffer<Empty> BufferErr4;
 
 [numthreads(1,1,1)]
 void main() {
-  (void)Buffer.__handle; // expected-error {{'__handle' is a private member of 'hlsl::StructuredBuffer<vector<float, 3>>'}}
+  (void)Buff.__handle; // expected-error {{'__handle' is a private member of 'hlsl::StructuredBuffer<vector<float, 3>>'}}
   // expected-note@* {{implicitly declared private here}}
 }

bogner

We should also add AST tests in clang/test/AST/HLSL/TypedBuffers-AST.hlsl

inbelic

How does this/will this handle enforcing that it is a read-only buffer?

V-FEXrt · 2025-05-27T17:37:47Z

@inbelic From Justin, looks like it doesn't :) (and this is a bug) https://hlsl.godbolt.org/z/sqMMffh6K

I'm going to spin that off into its own task separate from this one so this doesn't get bogged down

inbelic

LGTM given we have a way of tracking making sure it will be read-only

bogner

Looks good (noting that we're matching the pre-existing buggy behaviour of StructuredBuffer and will follow up to fix that for both)

V-FEXrt · 2025-05-28T19:58:31Z

Tracking bug! #141842

V-FEXrt added 2 commits May 22, 2025 09:20

[HLSL] Add Buffer def to frontend

9868eef

Merge branch 'main' into 138902-define-buffer

c6b9301

llvmbot added clang Clang issues not falling into any other category clang:frontend Language frontend issues, e.g. anything involving "Sema" HLSL HLSL Language Support labels May 22, 2025

bogner reviewed May 22, 2025

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Address comments

81b977d

inbelic reviewed May 23, 2025

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inbelic approved these changes May 27, 2025

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bogner approved these changes May 27, 2025

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V-FEXrt merged commit cb7f4ff into llvm:main May 28, 2025
12 checks passed

V-FEXrt deleted the 138902-define-buffer branch May 28, 2025 19:58

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[HLSL] Add Buffer def to frontend #141086

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[HLSL] Add Buffer def to frontend #141086

[HLSL] Add Buffer def to frontend #141086

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