[DirectX] Add static sampler support to root signature #143422

joaosaffran · 2025-06-09T18:57:16Z

Implements static samplers parsing from root signature metadata representation. This is required to support Root Signatures in HLSL.
Closes: #126641

llvmbot · 2025-06-09T18:57:54Z

@llvm/pr-subscribers-backend-directx

Author: None (joaosaffran)

Changes

This patch introduces the following changes to the DirectX container implementation:

Add static sampler support to root signatures:
- Implement parsing and validation of static sampler parameters
- Add verification for sampler attributes (filter, addressing, LOD, etc.)
- Update root signature writing to handle static samplers
- Add test coverage for static sampler validation

Testing:

Added new test files for static sampler validation
Added tests for all possible invalid sampler parameters
Existing root signature tests continue to pass

Patch is 32.62 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/143422.diff

17 Files Affected:

(modified) llvm/lib/MC/DXContainerRootSignature.cpp (+24-17)
(modified) llvm/lib/Target/DirectX/DXILRootSignature.cpp (+253)
(modified) llvm/lib/Target/DirectX/DXILRootSignature.h (+1)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-BorderColor.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-ComparisonFunc.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-Filter.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MaxAnisotropy.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MaxLod.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MinLod.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MinLopBias.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-RegisterSpace.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-ShaderRegister.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-ShaderVisibility.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers.ll (+42)

diff --git a/llvm/lib/MC/DXContainerRootSignature.cpp b/llvm/lib/MC/DXContainerRootSignature.cpp
index 6c71823a51f85..77d648a739b87 100644
--- a/llvm/lib/MC/DXContainerRootSignature.cpp
+++ b/llvm/lib/MC/DXContainerRootSignature.cpp
@@ -71,12 +71,16 @@ void RootSignatureDesc::write(raw_ostream &OS) const {
   BOS.reserveExtraSpace(getSize());
 
   const uint32_t NumParameters = ParametersContainer.size();
-
+  const uint32_t NumSamplers = StaticSamplers.size();
   support::endian::write(BOS, Version, llvm::endianness::little);
   support::endian::write(BOS, NumParameters, llvm::endianness::little);
   support::endian::write(BOS, RootParameterOffset, llvm::endianness::little);
-  support::endian::write(BOS, NumStaticSamplers, llvm::endianness::little);
-  support::endian::write(BOS, StaticSamplersOffset, llvm::endianness::little);
+  support::endian::write(BOS, NumSamplers, llvm::endianness::little);
+  uint32_t SSO = StaticSamplersOffset;
+  if (NumSamplers > 0)
+    SSO = writePlaceholder(BOS);
+  else
+    support::endian::write(BOS, SSO, llvm::endianness::little);
   support::endian::write(BOS, Flags, llvm::endianness::little);
 
   SmallVector<uint32_t> ParamsOffsets;
@@ -142,20 +146,23 @@ void RootSignatureDesc::write(raw_ostream &OS) const {
     }
     }
   }
-  for (const auto &S : StaticSamplers) {
-    support::endian::write(BOS, S.Filter, llvm::endianness::little);
-    support::endian::write(BOS, S.AddressU, llvm::endianness::little);
-    support::endian::write(BOS, S.AddressV, llvm::endianness::little);
-    support::endian::write(BOS, S.AddressW, llvm::endianness::little);
-    support::endian::write(BOS, S.MipLODBias, llvm::endianness::little);
-    support::endian::write(BOS, S.MaxAnisotropy, llvm::endianness::little);
-    support::endian::write(BOS, S.ComparisonFunc, llvm::endianness::little);
-    support::endian::write(BOS, S.BorderColor, llvm::endianness::little);
-    support::endian::write(BOS, S.MinLOD, llvm::endianness::little);
-    support::endian::write(BOS, S.MaxLOD, llvm::endianness::little);
-    support::endian::write(BOS, S.ShaderRegister, llvm::endianness::little);
-    support::endian::write(BOS, S.RegisterSpace, llvm::endianness::little);
-    support::endian::write(BOS, S.ShaderVisibility, llvm::endianness::little);
+  if (NumSamplers > 0) {
+    rewriteOffsetToCurrentByte(BOS, SSO);
+    for (const auto &S : StaticSamplers) {
+      support::endian::write(BOS, S.Filter, llvm::endianness::little);
+      support::endian::write(BOS, S.AddressU, llvm::endianness::little);
+      support::endian::write(BOS, S.AddressV, llvm::endianness::little);
+      support::endian::write(BOS, S.AddressW, llvm::endianness::little);
+      support::endian::write(BOS, S.MipLODBias, llvm::endianness::little);
+      support::endian::write(BOS, S.MaxAnisotropy, llvm::endianness::little);
+      support::endian::write(BOS, S.ComparisonFunc, llvm::endianness::little);
+      support::endian::write(BOS, S.BorderColor, llvm::endianness::little);
+      support::endian::write(BOS, S.MinLOD, llvm::endianness::little);
+      support::endian::write(BOS, S.MaxLOD, llvm::endianness::little);
+      support::endian::write(BOS, S.ShaderRegister, llvm::endianness::little);
+      support::endian::write(BOS, S.RegisterSpace, llvm::endianness::little);
+      support::endian::write(BOS, S.ShaderVisibility, llvm::endianness::little);
+    }
   }
   assert(Storage.size() == getSize());
   OS.write(Storage.data(), Storage.size());
diff --git a/llvm/lib/Target/DirectX/DXILRootSignature.cpp b/llvm/lib/Target/DirectX/DXILRootSignature.cpp
index b38ab516a3bb5..0cd3dc72505ef 100644
--- a/llvm/lib/Target/DirectX/DXILRootSignature.cpp
+++ b/llvm/lib/Target/DirectX/DXILRootSignature.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+#include <cmath>
 #include <cstdint>
 #include <optional>
 #include <utility>
@@ -55,6 +56,13 @@ static std::optional<uint32_t> extractMdIntValue(MDNode *Node,
   return std::nullopt;
 }
 
+static std::optional<APFloat> extractMdFloatValue(MDNode *Node,
+                                                  unsigned int OpId) {
+  if (auto *CI = mdconst::dyn_extract<ConstantFP>(Node->getOperand(OpId).get()))
+    return CI->getValue();
+  return std::nullopt;
+}
+
 static std::optional<StringRef> extractMdStringValue(MDNode *Node,
                                                      unsigned int OpId) {
   MDString *NodeText = dyn_cast<MDString>(Node->getOperand(OpId));
@@ -258,6 +266,81 @@ static bool parseDescriptorTable(LLVMContext *Ctx,
   return false;
 }
 
+static bool parseStaticSampler(LLVMContext *Ctx, mcdxbc::RootSignatureDesc &RSD,
+                               MDNode *StaticSamplerNode) {
+  if (StaticSamplerNode->getNumOperands() != 14)
+    return reportError(Ctx, "Invalid format for Static Sampler");
+
+  dxbc::RTS0::v1::StaticSampler Sampler;
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 1))
+    Sampler.Filter = *Val;
+  else
+    return reportError(Ctx, "Invalid value for Filter");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 2))
+    Sampler.AddressU = *Val;
+  else
+    return reportError(Ctx, "Invalid value for AddressU");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 3))
+    Sampler.AddressV = *Val;
+  else
+    return reportError(Ctx, "Invalid value for AddressV");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 4))
+    Sampler.AddressW = *Val;
+  else
+    return reportError(Ctx, "Invalid value for AddressW");
+
+  if (std::optional<APFloat> Val = extractMdFloatValue(StaticSamplerNode, 5))
+    Sampler.MipLODBias = Val->convertToFloat();
+  else
+    return reportError(Ctx, "Invalid value for MipLODBias");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 6))
+    Sampler.MaxAnisotropy = *Val;
+  else
+    return reportError(Ctx, "Invalid value for MaxAnisotropy");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 7))
+    Sampler.ComparisonFunc = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ComparisonFunc ");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 8))
+    Sampler.BorderColor = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ComparisonFunc ");
+
+  if (std::optional<APFloat> Val = extractMdFloatValue(StaticSamplerNode, 9))
+    Sampler.MinLOD = Val->convertToFloat();
+  else
+    return reportError(Ctx, "Invalid value for MinLOD");
+
+  if (std::optional<APFloat> Val = extractMdFloatValue(StaticSamplerNode, 10))
+    Sampler.MaxLOD = Val->convertToFloat();
+  else
+    return reportError(Ctx, "Invalid value for MaxLOD");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 11))
+    Sampler.ShaderRegister = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ShaderRegister");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 12))
+    Sampler.RegisterSpace = *Val;
+  else
+    return reportError(Ctx, "Invalid value for RegisterSpace");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 13))
+    Sampler.ShaderVisibility = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ShaderVisibility");
+
+  RSD.StaticSamplers.push_back(Sampler);
+  return false;
+}
+
 static bool parseRootSignatureElement(LLVMContext *Ctx,
                                       mcdxbc::RootSignatureDesc &RSD,
                                       MDNode *Element) {
@@ -273,6 +356,7 @@ static bool parseRootSignatureElement(LLVMContext *Ctx,
           .Case("RootSRV", RootSignatureElementKind::SRV)
           .Case("RootUAV", RootSignatureElementKind::UAV)
           .Case("DescriptorTable", RootSignatureElementKind::DescriptorTable)
+          .Case("StaticSampler", RootSignatureElementKind::StaticSamplers)
           .Default(RootSignatureElementKind::Error);
 
   switch (ElementKind) {
@@ -287,6 +371,8 @@ static bool parseRootSignatureElement(LLVMContext *Ctx,
     return parseRootDescriptors(Ctx, RSD, Element, ElementKind);
   case RootSignatureElementKind::DescriptorTable:
     return parseDescriptorTable(Ctx, RSD, Element);
+  case RootSignatureElementKind::StaticSamplers:
+    return parseStaticSampler(Ctx, RSD, Element);
   case RootSignatureElementKind::Error:
     return reportError(Ctx, "Invalid Root Signature Element: " + *ElementText);
   }
@@ -347,6 +433,7 @@ static bool isFlagSet(uint32_t Flags, FlagTypes... FlagsToCheck) {
 
 static bool verifyDescriptorRangeFlag(uint32_t Version, uint32_t Type,
                                       uint32_t Flags) {
+
   bool IsSampler =
       (Type == llvm::to_underlying(dxbc::DescriptorRangeType::Sampler));
 
@@ -399,6 +486,127 @@ static bool verifyDescriptorRangeFlag(uint32_t Version, uint32_t Type,
   return false;
 }
 
+static bool verifySamplerFilter(uint32_t Filter) {
+  switch (Filter) {
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::ANISOTROPIC):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::COMPARISON_ANISOTROPIC):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MINIMUM_ANISOTROPIC):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MAXIMUM_ANISOTROPIC):
+    return true;
+  }
+  return false;
+}
+
+// Values allowed here:
+// https://learn.microsoft.com/en-us/windows/win32/api/d3d12/ne-d3d12-d3d12_texture_address_mode#syntax
+static bool verifyAddress(uint32_t Address) {
+  switch (Address) {
+  case llvm::to_underlying(dxbc::TextureAddressMode::Border):
+  case llvm::to_underlying(dxbc::TextureAddressMode::Clamp):
+  case llvm::to_underlying(dxbc::TextureAddressMode::Mirror):
+  case llvm::to_underlying(dxbc::TextureAddressMode::MirrorOnce):
+  case llvm::to_underlying(dxbc::TextureAddressMode::Wrap):
+    return true;
+  }
+
+  return false;
+}
+
+static bool verifyMipLODBias(float MipLODBias) {
+  return MipLODBias >= -16.f && MipLODBias <= 16.f;
+}
+
+static bool verifyMaxAnisotropy(uint32_t MaxAnisotropy) {
+  return MaxAnisotropy <= 16u;
+}
+
+static bool verifyComparisonFunc(uint32_t ComparisonFunc) {
+  switch (ComparisonFunc) {
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Never):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Less):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Equal):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::LessEqual):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Greater):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::NotEqual):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::GreaterEqual):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Always):
+    return true;
+  }
+  return false;
+}
+
+static bool verifyBorderColor(uint32_t BorderColor) {
+  switch (BorderColor) {
+  case llvm::to_underlying(dxbc::SamplersBorderColor::TransparentBlack):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueBlack):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueWhite):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueBlackUint):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueWhiteUint):
+    return true;
+  }
+  return false;
+}
+
+static bool verifyLOD(float LOD) { return !std::isnan(LOD); }
+
 static bool validate(LLVMContext *Ctx, const mcdxbc::RootSignatureDesc &RSD) {
 
   if (!verifyVersion(RSD.Version)) {
@@ -456,6 +664,48 @@ static bool validate(LLVMContext *Ctx, const mcdxbc::RootSignatureDesc &RSD) {
     }
   }
 
+  for (const dxbc::RTS0::v1::StaticSampler &Sampler : RSD.StaticSamplers) {
+    if (!verifySamplerFilter(Sampler.Filter))
+      return reportValueError(Ctx, "Filter", Sampler.Filter);
+
+    if (!verifyAddress(Sampler.AddressU))
+      return reportValueError(Ctx, "AddressU", Sampler.AddressU);
+
+    if (!verifyAddress(Sampler.AddressV))
+      return reportValueError(Ctx, "AddressV", Sampler.AddressV);
+
+    if (!verifyAddress(Sampler.AddressW))
+      return reportValueError(Ctx, "AddressW", Sampler.AddressW);
+
+    if (!verifyMipLODBias(Sampler.MipLODBias))
+      return reportValueError(Ctx, "MipLODBias", Sampler.MipLODBias);
+
+    if (!verifyMaxAnisotropy(Sampler.MaxAnisotropy))
+      return reportValueError(Ctx, "MaxAnisotropy", Sampler.MaxAnisotropy);
+
+    if (!verifyComparisonFunc(Sampler.ComparisonFunc))
+      return reportValueError(Ctx, "ComparisonFunc", Sampler.ComparisonFunc);
+
+    if (!verifyBorderColor(Sampler.BorderColor))
+      return reportValueError(Ctx, "BorderColor", Sampler.BorderColor);
+
+    if (!verifyLOD(Sampler.MinLOD))
+      return reportValueError(Ctx, "MinLOD", Sampler.MinLOD);
+
+    if (!verifyLOD(Sampler.MaxLOD))
+      return reportValueError(Ctx, "MaxLOD", Sampler.MaxLOD);
+
+    if (!verifyRegisterValue(Sampler.ShaderRegister))
+      return reportValueError(Ctx, "ShaderRegister", Sampler.ShaderRegister);
+
+    if (!verifyRegisterSpace(Sampler.RegisterSpace))
+      return reportValueError(Ctx, "RegisterSpace", Sampler.RegisterSpace);
+
+    if (!dxbc::isValidShaderVisibility(Sampler.ShaderVisibility))
+      return reportValueError(Ctx, "ShaderVisibility",
+                              Sampler.ShaderVisibility);
+  }
+
   return false;
 }
 
@@ -529,6 +779,9 @@ analyzeModule(Module &M) {
     // offset will always equal to the header size.
     RSD.RootParameterOffset = sizeof(dxbc::RTS0::v1::RootSignatureHeader);
 
+    // static sampler offset is calculated when writting dxcontainer.
+    RSD.StaticSamplersOffset = 0u;
+
     if (parse(Ctx, RSD, RootElementListNode) || validate(Ctx, RSD)) {
       return RSDMap;
     }
diff --git a/llvm/lib/Target/DirectX/DXILRootSignature.h b/llvm/lib/Target/DirectX/DXILRootSignature.h
index b45cebc15fd39..be5cc78bc6bdf 100644
--- a/llvm/lib/Target/DirectX/DXILRootSignature.h
+++ b/llvm/lib/Target/DirectX/DXILRootSignature.h
@@ -32,6 +32,7 @@ enum class RootSignatureElementKind {
   UAV = 4,
   CBV = 5,
   DescriptorTable = 6,
+  StaticSamplers = 7
 };
 class RootSignatureAnalysis : public AnalysisInfoMixin<RootSignatureAnalysis> {
   friend AnalysisInfoMixin<RootSignatureAnalysis>;
diff --git a/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll
new file mode 100644
index 0000000000000..124803e36a450
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll
@@ -0,0 +1,19 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: error: Invalid value for AddressU: 666
+; CHECK-NOT: Root Signature Definitions
+
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"StaticSampler", i32 4, i32 666, i32 3, i32 5, float 0x3FF6CCCCC0000000, i32 9, i32 3, i32 2, float -1.280000e+02, float 1.280000e+02, i32 42, i32 0, i32 0 }
diff --git a/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll
new file mode 100644
index 0000000000000..e2c5de1c36a0c
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll
@@ -0,0 +1,19 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: error: Invalid value for AddressV: 666
+; CHECK-NOT: Root Signature Definitions
+
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"StaticSampler", i32 4, i32 2, i32 666, i32 5, float 0x3FF6CCCCC0000000, i32 9, i32 3, i32 2, float -1.280000e+02, float 1.280000e+02, i32 42, i32 0, i32 0 }
diff --git a/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll
new file mode 100644
index 0000000000000..08fc8fa9e5093
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll
@@ -0,0 +1,19 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: error: Invalid value for AddressW: 666
+; CHECK-NOT: Root Signature Definitions
+
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"StaticSampler", i32 4, i32 2, i32 3, i32 666, float 0x3FF6CCCCC0000000, i32 9, i32 3, i32 2, float...
[truncated]

llvmbot · 2025-06-09T18:57:55Z

@llvm/pr-subscribers-mc

Author: None (joaosaffran)

Changes

This patch introduces the following changes to the DirectX container implementation:

Add static sampler support to root signatures:
- Implement parsing and validation of static sampler parameters
- Add verification for sampler attributes (filter, addressing, LOD, etc.)
- Update root signature writing to handle static samplers
- Add test coverage for static sampler validation

Testing:

Added new test files for static sampler validation
Added tests for all possible invalid sampler parameters
Existing root signature tests continue to pass

Patch is 32.62 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/143422.diff

17 Files Affected:

(modified) llvm/lib/MC/DXContainerRootSignature.cpp (+24-17)
(modified) llvm/lib/Target/DirectX/DXILRootSignature.cpp (+253)
(modified) llvm/lib/Target/DirectX/DXILRootSignature.h (+1)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-BorderColor.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-ComparisonFunc.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-Filter.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MaxAnisotropy.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MaxLod.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MinLod.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-MinLopBias.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-RegisterSpace.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-ShaderRegister.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-ShaderVisibility.ll (+19)
(added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers.ll (+42)

diff --git a/llvm/lib/MC/DXContainerRootSignature.cpp b/llvm/lib/MC/DXContainerRootSignature.cpp
index 6c71823a51f85..77d648a739b87 100644
--- a/llvm/lib/MC/DXContainerRootSignature.cpp
+++ b/llvm/lib/MC/DXContainerRootSignature.cpp
@@ -71,12 +71,16 @@ void RootSignatureDesc::write(raw_ostream &OS) const {
   BOS.reserveExtraSpace(getSize());
 
   const uint32_t NumParameters = ParametersContainer.size();
-
+  const uint32_t NumSamplers = StaticSamplers.size();
   support::endian::write(BOS, Version, llvm::endianness::little);
   support::endian::write(BOS, NumParameters, llvm::endianness::little);
   support::endian::write(BOS, RootParameterOffset, llvm::endianness::little);
-  support::endian::write(BOS, NumStaticSamplers, llvm::endianness::little);
-  support::endian::write(BOS, StaticSamplersOffset, llvm::endianness::little);
+  support::endian::write(BOS, NumSamplers, llvm::endianness::little);
+  uint32_t SSO = StaticSamplersOffset;
+  if (NumSamplers > 0)
+    SSO = writePlaceholder(BOS);
+  else
+    support::endian::write(BOS, SSO, llvm::endianness::little);
   support::endian::write(BOS, Flags, llvm::endianness::little);
 
   SmallVector<uint32_t> ParamsOffsets;
@@ -142,20 +146,23 @@ void RootSignatureDesc::write(raw_ostream &OS) const {
     }
     }
   }
-  for (const auto &S : StaticSamplers) {
-    support::endian::write(BOS, S.Filter, llvm::endianness::little);
-    support::endian::write(BOS, S.AddressU, llvm::endianness::little);
-    support::endian::write(BOS, S.AddressV, llvm::endianness::little);
-    support::endian::write(BOS, S.AddressW, llvm::endianness::little);
-    support::endian::write(BOS, S.MipLODBias, llvm::endianness::little);
-    support::endian::write(BOS, S.MaxAnisotropy, llvm::endianness::little);
-    support::endian::write(BOS, S.ComparisonFunc, llvm::endianness::little);
-    support::endian::write(BOS, S.BorderColor, llvm::endianness::little);
-    support::endian::write(BOS, S.MinLOD, llvm::endianness::little);
-    support::endian::write(BOS, S.MaxLOD, llvm::endianness::little);
-    support::endian::write(BOS, S.ShaderRegister, llvm::endianness::little);
-    support::endian::write(BOS, S.RegisterSpace, llvm::endianness::little);
-    support::endian::write(BOS, S.ShaderVisibility, llvm::endianness::little);
+  if (NumSamplers > 0) {
+    rewriteOffsetToCurrentByte(BOS, SSO);
+    for (const auto &S : StaticSamplers) {
+      support::endian::write(BOS, S.Filter, llvm::endianness::little);
+      support::endian::write(BOS, S.AddressU, llvm::endianness::little);
+      support::endian::write(BOS, S.AddressV, llvm::endianness::little);
+      support::endian::write(BOS, S.AddressW, llvm::endianness::little);
+      support::endian::write(BOS, S.MipLODBias, llvm::endianness::little);
+      support::endian::write(BOS, S.MaxAnisotropy, llvm::endianness::little);
+      support::endian::write(BOS, S.ComparisonFunc, llvm::endianness::little);
+      support::endian::write(BOS, S.BorderColor, llvm::endianness::little);
+      support::endian::write(BOS, S.MinLOD, llvm::endianness::little);
+      support::endian::write(BOS, S.MaxLOD, llvm::endianness::little);
+      support::endian::write(BOS, S.ShaderRegister, llvm::endianness::little);
+      support::endian::write(BOS, S.RegisterSpace, llvm::endianness::little);
+      support::endian::write(BOS, S.ShaderVisibility, llvm::endianness::little);
+    }
   }
   assert(Storage.size() == getSize());
   OS.write(Storage.data(), Storage.size());
diff --git a/llvm/lib/Target/DirectX/DXILRootSignature.cpp b/llvm/lib/Target/DirectX/DXILRootSignature.cpp
index b38ab516a3bb5..0cd3dc72505ef 100644
--- a/llvm/lib/Target/DirectX/DXILRootSignature.cpp
+++ b/llvm/lib/Target/DirectX/DXILRootSignature.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+#include <cmath>
 #include <cstdint>
 #include <optional>
 #include <utility>
@@ -55,6 +56,13 @@ static std::optional<uint32_t> extractMdIntValue(MDNode *Node,
   return std::nullopt;
 }
 
+static std::optional<APFloat> extractMdFloatValue(MDNode *Node,
+                                                  unsigned int OpId) {
+  if (auto *CI = mdconst::dyn_extract<ConstantFP>(Node->getOperand(OpId).get()))
+    return CI->getValue();
+  return std::nullopt;
+}
+
 static std::optional<StringRef> extractMdStringValue(MDNode *Node,
                                                      unsigned int OpId) {
   MDString *NodeText = dyn_cast<MDString>(Node->getOperand(OpId));
@@ -258,6 +266,81 @@ static bool parseDescriptorTable(LLVMContext *Ctx,
   return false;
 }
 
+static bool parseStaticSampler(LLVMContext *Ctx, mcdxbc::RootSignatureDesc &RSD,
+                               MDNode *StaticSamplerNode) {
+  if (StaticSamplerNode->getNumOperands() != 14)
+    return reportError(Ctx, "Invalid format for Static Sampler");
+
+  dxbc::RTS0::v1::StaticSampler Sampler;
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 1))
+    Sampler.Filter = *Val;
+  else
+    return reportError(Ctx, "Invalid value for Filter");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 2))
+    Sampler.AddressU = *Val;
+  else
+    return reportError(Ctx, "Invalid value for AddressU");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 3))
+    Sampler.AddressV = *Val;
+  else
+    return reportError(Ctx, "Invalid value for AddressV");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 4))
+    Sampler.AddressW = *Val;
+  else
+    return reportError(Ctx, "Invalid value for AddressW");
+
+  if (std::optional<APFloat> Val = extractMdFloatValue(StaticSamplerNode, 5))
+    Sampler.MipLODBias = Val->convertToFloat();
+  else
+    return reportError(Ctx, "Invalid value for MipLODBias");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 6))
+    Sampler.MaxAnisotropy = *Val;
+  else
+    return reportError(Ctx, "Invalid value for MaxAnisotropy");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 7))
+    Sampler.ComparisonFunc = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ComparisonFunc ");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 8))
+    Sampler.BorderColor = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ComparisonFunc ");
+
+  if (std::optional<APFloat> Val = extractMdFloatValue(StaticSamplerNode, 9))
+    Sampler.MinLOD = Val->convertToFloat();
+  else
+    return reportError(Ctx, "Invalid value for MinLOD");
+
+  if (std::optional<APFloat> Val = extractMdFloatValue(StaticSamplerNode, 10))
+    Sampler.MaxLOD = Val->convertToFloat();
+  else
+    return reportError(Ctx, "Invalid value for MaxLOD");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 11))
+    Sampler.ShaderRegister = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ShaderRegister");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 12))
+    Sampler.RegisterSpace = *Val;
+  else
+    return reportError(Ctx, "Invalid value for RegisterSpace");
+
+  if (std::optional<uint32_t> Val = extractMdIntValue(StaticSamplerNode, 13))
+    Sampler.ShaderVisibility = *Val;
+  else
+    return reportError(Ctx, "Invalid value for ShaderVisibility");
+
+  RSD.StaticSamplers.push_back(Sampler);
+  return false;
+}
+
 static bool parseRootSignatureElement(LLVMContext *Ctx,
                                       mcdxbc::RootSignatureDesc &RSD,
                                       MDNode *Element) {
@@ -273,6 +356,7 @@ static bool parseRootSignatureElement(LLVMContext *Ctx,
           .Case("RootSRV", RootSignatureElementKind::SRV)
           .Case("RootUAV", RootSignatureElementKind::UAV)
           .Case("DescriptorTable", RootSignatureElementKind::DescriptorTable)
+          .Case("StaticSampler", RootSignatureElementKind::StaticSamplers)
           .Default(RootSignatureElementKind::Error);
 
   switch (ElementKind) {
@@ -287,6 +371,8 @@ static bool parseRootSignatureElement(LLVMContext *Ctx,
     return parseRootDescriptors(Ctx, RSD, Element, ElementKind);
   case RootSignatureElementKind::DescriptorTable:
     return parseDescriptorTable(Ctx, RSD, Element);
+  case RootSignatureElementKind::StaticSamplers:
+    return parseStaticSampler(Ctx, RSD, Element);
   case RootSignatureElementKind::Error:
     return reportError(Ctx, "Invalid Root Signature Element: " + *ElementText);
   }
@@ -347,6 +433,7 @@ static bool isFlagSet(uint32_t Flags, FlagTypes... FlagsToCheck) {
 
 static bool verifyDescriptorRangeFlag(uint32_t Version, uint32_t Type,
                                       uint32_t Flags) {
+
   bool IsSampler =
       (Type == llvm::to_underlying(dxbc::DescriptorRangeType::Sampler));
 
@@ -399,6 +486,127 @@ static bool verifyDescriptorRangeFlag(uint32_t Version, uint32_t Type,
   return false;
 }
 
+static bool verifySamplerFilter(uint32_t Filter) {
+  switch (Filter) {
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::ANISOTROPIC):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::COMPARISON_MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::COMPARISON_ANISOTROPIC):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MINIMUM_MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MINIMUM_ANISOTROPIC):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_POINT_MAG_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_LINEAR_MAG_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_LINEAR_MIP_POINT):
+  case llvm::to_underlying(
+      dxbc::StaticSamplerFilter::MAXIMUM_MIN_MAG_MIP_LINEAR):
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MAXIMUM_ANISOTROPIC):
+    return true;
+  }
+  return false;
+}
+
+// Values allowed here:
+// https://learn.microsoft.com/en-us/windows/win32/api/d3d12/ne-d3d12-d3d12_texture_address_mode#syntax
+static bool verifyAddress(uint32_t Address) {
+  switch (Address) {
+  case llvm::to_underlying(dxbc::TextureAddressMode::Border):
+  case llvm::to_underlying(dxbc::TextureAddressMode::Clamp):
+  case llvm::to_underlying(dxbc::TextureAddressMode::Mirror):
+  case llvm::to_underlying(dxbc::TextureAddressMode::MirrorOnce):
+  case llvm::to_underlying(dxbc::TextureAddressMode::Wrap):
+    return true;
+  }
+
+  return false;
+}
+
+static bool verifyMipLODBias(float MipLODBias) {
+  return MipLODBias >= -16.f && MipLODBias <= 16.f;
+}
+
+static bool verifyMaxAnisotropy(uint32_t MaxAnisotropy) {
+  return MaxAnisotropy <= 16u;
+}
+
+static bool verifyComparisonFunc(uint32_t ComparisonFunc) {
+  switch (ComparisonFunc) {
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Never):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Less):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Equal):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::LessEqual):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Greater):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::NotEqual):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::GreaterEqual):
+  case llvm::to_underlying(dxbc::SamplersComparisonFunction::Always):
+    return true;
+  }
+  return false;
+}
+
+static bool verifyBorderColor(uint32_t BorderColor) {
+  switch (BorderColor) {
+  case llvm::to_underlying(dxbc::SamplersBorderColor::TransparentBlack):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueBlack):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueWhite):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueBlackUint):
+  case llvm::to_underlying(dxbc::SamplersBorderColor::OpaqueWhiteUint):
+    return true;
+  }
+  return false;
+}
+
+static bool verifyLOD(float LOD) { return !std::isnan(LOD); }
+
 static bool validate(LLVMContext *Ctx, const mcdxbc::RootSignatureDesc &RSD) {
 
   if (!verifyVersion(RSD.Version)) {
@@ -456,6 +664,48 @@ static bool validate(LLVMContext *Ctx, const mcdxbc::RootSignatureDesc &RSD) {
     }
   }
 
+  for (const dxbc::RTS0::v1::StaticSampler &Sampler : RSD.StaticSamplers) {
+    if (!verifySamplerFilter(Sampler.Filter))
+      return reportValueError(Ctx, "Filter", Sampler.Filter);
+
+    if (!verifyAddress(Sampler.AddressU))
+      return reportValueError(Ctx, "AddressU", Sampler.AddressU);
+
+    if (!verifyAddress(Sampler.AddressV))
+      return reportValueError(Ctx, "AddressV", Sampler.AddressV);
+
+    if (!verifyAddress(Sampler.AddressW))
+      return reportValueError(Ctx, "AddressW", Sampler.AddressW);
+
+    if (!verifyMipLODBias(Sampler.MipLODBias))
+      return reportValueError(Ctx, "MipLODBias", Sampler.MipLODBias);
+
+    if (!verifyMaxAnisotropy(Sampler.MaxAnisotropy))
+      return reportValueError(Ctx, "MaxAnisotropy", Sampler.MaxAnisotropy);
+
+    if (!verifyComparisonFunc(Sampler.ComparisonFunc))
+      return reportValueError(Ctx, "ComparisonFunc", Sampler.ComparisonFunc);
+
+    if (!verifyBorderColor(Sampler.BorderColor))
+      return reportValueError(Ctx, "BorderColor", Sampler.BorderColor);
+
+    if (!verifyLOD(Sampler.MinLOD))
+      return reportValueError(Ctx, "MinLOD", Sampler.MinLOD);
+
+    if (!verifyLOD(Sampler.MaxLOD))
+      return reportValueError(Ctx, "MaxLOD", Sampler.MaxLOD);
+
+    if (!verifyRegisterValue(Sampler.ShaderRegister))
+      return reportValueError(Ctx, "ShaderRegister", Sampler.ShaderRegister);
+
+    if (!verifyRegisterSpace(Sampler.RegisterSpace))
+      return reportValueError(Ctx, "RegisterSpace", Sampler.RegisterSpace);
+
+    if (!dxbc::isValidShaderVisibility(Sampler.ShaderVisibility))
+      return reportValueError(Ctx, "ShaderVisibility",
+                              Sampler.ShaderVisibility);
+  }
+
   return false;
 }
 
@@ -529,6 +779,9 @@ analyzeModule(Module &M) {
     // offset will always equal to the header size.
     RSD.RootParameterOffset = sizeof(dxbc::RTS0::v1::RootSignatureHeader);
 
+    // static sampler offset is calculated when writting dxcontainer.
+    RSD.StaticSamplersOffset = 0u;
+
     if (parse(Ctx, RSD, RootElementListNode) || validate(Ctx, RSD)) {
       return RSDMap;
     }
diff --git a/llvm/lib/Target/DirectX/DXILRootSignature.h b/llvm/lib/Target/DirectX/DXILRootSignature.h
index b45cebc15fd39..be5cc78bc6bdf 100644
--- a/llvm/lib/Target/DirectX/DXILRootSignature.h
+++ b/llvm/lib/Target/DirectX/DXILRootSignature.h
@@ -32,6 +32,7 @@ enum class RootSignatureElementKind {
   UAV = 4,
   CBV = 5,
   DescriptorTable = 6,
+  StaticSamplers = 7
 };
 class RootSignatureAnalysis : public AnalysisInfoMixin<RootSignatureAnalysis> {
   friend AnalysisInfoMixin<RootSignatureAnalysis>;
diff --git a/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll
new file mode 100644
index 0000000000000..124803e36a450
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressU.ll
@@ -0,0 +1,19 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: error: Invalid value for AddressU: 666
+; CHECK-NOT: Root Signature Definitions
+
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"StaticSampler", i32 4, i32 666, i32 3, i32 5, float 0x3FF6CCCCC0000000, i32 9, i32 3, i32 2, float -1.280000e+02, float 1.280000e+02, i32 42, i32 0, i32 0 }
diff --git a/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll
new file mode 100644
index 0000000000000..e2c5de1c36a0c
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressV.ll
@@ -0,0 +1,19 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: error: Invalid value for AddressV: 666
+; CHECK-NOT: Root Signature Definitions
+
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"StaticSampler", i32 4, i32 2, i32 666, i32 5, float 0x3FF6CCCCC0000000, i32 9, i32 3, i32 2, float -1.280000e+02, float 1.280000e+02, i32 42, i32 0, i32 0 }
diff --git a/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll
new file mode 100644
index 0000000000000..08fc8fa9e5093
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-StaticSamplers-Invalid-AddressW.ll
@@ -0,0 +1,19 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: error: Invalid value for AddressW: 666
+; CHECK-NOT: Root Signature Definitions
+
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"StaticSampler", i32 4, i32 2, i32 3, i32 666, float 0x3FF6CCCCC0000000, i32 9, i32 3, i32 2, float...
[truncated]

diff

inbelic · 2025-06-12T15:53:22Z

llvm/lib/Target/DirectX/DXILRootSignature.cpp

@@ -399,6 +486,127 @@ static bool verifyDescriptorRangeFlag(uint32_t Version, uint32_t Type,
  return false;
 }

+static bool verifySamplerFilter(uint32_t Filter) {
+  switch (Filter) {
+  case llvm::to_underlying(dxbc::StaticSamplerFilter::MIN_MAG_MIP_POINT):


We might be able to use a similar BitEnumMask technique here?

Or just a <= comparison?

inbelic · 2025-06-12T15:58:23Z

llvm/lib/Target/DirectX/DXILRootSignature.cpp

+    if (!verifySamplerFilter(Sampler.Filter))
+      return reportValueError(Ctx, "Filter", Sampler.Filter);
+
+    if (!verifyAddress(Sampler.AddressU))


One thought that just came up. I don't think it is required for us to early exit on all these verifications.

Maybe we can report all invalid errors in one go rather than exiting on the first one? Can you provide an argument for why or why not?

I would assume reporting all errors (so long as they aren't too verbose) reduces the number of compile cycles for the user to correct their input.

joaosaffran requested a review from inbelic June 9, 2025 18:57

llvmbot added mc Machine (object) code backend:DirectX labels Jun 9, 2025

joaosaffran requested a review from bogner June 9, 2025 18:57

joaosaffran assigned inbelic and bogner Jun 9, 2025

inbelic reviewed Jun 12, 2025

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joaosaffran changed the title ~~[DirectX] Add static sampler support to root signature and fix descriptor range flags~~ [DirectX] Add static sampler support to root signature Jun 12, 2025

joaosaffran changed the base branch from users/joaosaffran/142492 to main June 12, 2025 19:50

joaosaffran changed the base branch from main to users/joaosaffran/143201 June 12, 2025 19:51

joaosaffran changed the base branch from users/joaosaffran/143201 to users/joaosaffran/142492 June 12, 2025 19:51

joaosaffran changed the base branch from users/joaosaffran/142492 to main June 12, 2025 19:54

joaosaffran changed the base branch from main to users/joaosaffran/142492 June 12, 2025 19:55

joaosaffran added 6 commits June 12, 2025 19:56

adding metadata support for static samplers

9f51858

add validations

fb9c7c4

adding tests

611f0bb

addressing comments

42beb33

fix

0995050

rebase

24f38bd

joaosaffran force-pushed the metadata/static-samplers branch from 0b4111a to 24f38bd Compare June 12, 2025 23:50

joaosaffran mentioned this pull request Jun 20, 2025

[DirectX] Improve error accumulation in root signature parsing #144465

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[DirectX] Add static sampler support to root signature #143422

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joaosaffran commented Jun 9, 2025 •

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