[DirectX] Add shader flags for heap resources

[hekota]

Descriptor-heap usage must be recorded in the shader feature flags. The DXILShaderFlags pass inspects each llvm.dx.resource.handlefromheap call and sets the SamplerDescriptorHeapIndexing shader flag when IsSamplerHeap is true, or ResourceDescriptorHeapIndexing flag when it is false.

Fixes #213825

[llvmorg-github-actions]

@llvm/pr-subscribers-backend-directx

Author: Helena Kotas (hekota)

Changes

Descriptor-heap usage must be recorded in the shader feature flags. The DXILShaderFlags pass inspects each llvm.dx.resource.handlefromheap call and sets the SamplerDescriptorHeapIndexing shader flag when IsSamplerHeap is true, or ResourceDescriptorHeapIndexing flag when it is false.

Fixes #213825

Depends on #216454

---

Full diff: https://github.com/llvm/llvm-project/pull/216461.diff

2 Files Affected:

• (modified) llvm/lib/Target/DirectX/DXILShaderFlags.cpp (+11-1)
• (added) llvm/test/CodeGen/DirectX/ShaderFlags/heap-resources.ll (+42)

diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
index 64d8dc33e3e60..b7c296b2bde6d 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
+++ b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
@@ -274,6 +274,16 @@ void ModuleShaderFlags::updateFunctionFlags(ComputedShaderFlags &CSF,
       }
       break;
     }
+    case Intrinsic::dx_resource_handlefromheap: {
+      if (auto *ConstInt = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
+        bool IsSamplerHeap = ConstInt->getValue().getBoolValue();
+        if (IsSamplerHeap)
+          CSF.SamplerDescriptorHeapIndexing = true;
+        else
+          CSF.ResourceDescriptorHeapIndexing = true;
+      }
+      break;
+    }
     case Intrinsic::dx_resource_load_typedbuffer: {
       dxil::ResourceTypeInfo &RTI =
           DRTM[cast<TargetExtType>(II->getArgOperand(0)->getType())];
@@ -342,7 +352,7 @@ ModuleShaderFlags::gatherGlobalModuleFlags(const Module &M,
     if (MMDI.ValidatorVersion < VersionTuple(1, 6)) {
       NumUAVs++;
     } else { // MMDI.ValidatorVersion >= VersionTuple(1, 6)
-      uint32_t Size = UAV.getBinding().Size;
+      uint32_t Size = UAV.getSize();
       uint32_t NewNum = NumUAVs + (Size == 0 ? ~0U : Size);
       if (NewNum < NumUAVs)
         NewNum = ~0U;
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/heap-resources.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/heap-resources.ll
new file mode 100644
index 0000000000000..d7e15a65aea3a
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/heap-resources.ll
@@ -0,0 +1,42 @@
+; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+; RUN: llc %s -disable-dxil-remove-unused-resources --filetype=obj -o - | obj2yaml | FileCheck %s --check-prefix=DXC
+
+; This test makes sure that the shader flags 'Resource descriptor heap indexing'
+; is set when the shader uses CreateHandleFromHeap instruction on a resource
+; descriptor heap.
+
+target triple = "dxil-pc-shadermodel6.6-library"
+
+; CHECK:      Combined Shader Flags for Module
+; CHECK-NEXT: Shader Flags Value: 0xc0000000
+
+; CHECK: Note: shader requires additional functionality:
+; CHECK:        Resource descriptor heap indexing
+; CHECK:        Sampler descriptor heap indexing
+;
+; CHECK: Function test_1 : 0x40000000
+define void @test_1() "hlsl.export" {
+  ; RWBuffer<float4> Buf = ResourceDescriptorHeap[3]
+  %typed = call target("dx.TypedBuffer", <4 x float>, 1, 0, 0)
+              @llvm.dx.resource.handlefromheap.tdx.TypedBuffer_v4f32_1_0_0(i32 3, i1 false)
+  ret void
+}
+
+; CHECK: Function test_2 : 0x80000000
+define void @test_2() "hlsl.export" {
+  ; SamplerState Samp = ResourceDescriptorHeap[100];
+  %samp = call target("dx.Sampler", 0)
+              @llvm.dx.resource.handlefromheap.tdx.Sampler_0(i32 100, i1 true)
+  ret void
+}
+
+!dx.valver = !{!0}
+!0 = !{i32 1, i32 8}
+
+; DXC: - Name:            SFI0
+; DXC-NEXT:     Size:            8
+; DXC-NEXT:     Flags:
+; DXC:             ResourceDescriptorHeapIndexing: true
+; DXC:             SamplerDescriptorHeapIndexing: true
+; DXC:       NextUnusedBit:   false
+

[bob80905]

looks good, just some nits. Also, random curiosity, we expect a diagnostic / a validation failure if the operand (the index) is not a constant? Has that been previously validated by the point of the code you've written?

[hekota]

looks good, just some nits. Also, random curiosity, we expect a diagnostic / a validation failure if the operand (the index) is not a constant? Has that been previously validated by the point of the code you've written?

The Index operand is allowed to be non-constant so the resources can be indexed dynamically. The second isSamplerHeap is supposed to be constant and can add validation for that to the lowering PR (#216459).

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