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[DirectX] Removing dxbc DescriptorRange from mcbxdc #154629

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Merged
merged 27 commits into from
Sep 10, 2025
Merged

[DirectX] Removing dxbc DescriptorRange from mcbxdc #154629

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31ec5e5
making parameter type and shader visibility use enums
joaosaffran Aug 19, 2025
1690a9c
clean up
joaosaffran Aug 19, 2025
f6f2e61
removing root parameter header from MC
joaosaffran Aug 19, 2025
6539364
clean up
joaosaffran Aug 19, 2025
1d29111
fix whitespace in test
joaosaffran Aug 19, 2025
8eb82fd
adding missing import
joaosaffran Aug 19, 2025
d38c00d
remove unused
joaosaffran Aug 19, 2025
3b25b34
save a copy
joaosaffran Aug 19, 2025
567a3d4
remove default constructor
joaosaffran Aug 19, 2025
fb248da
rename visibility
joaosaffran Aug 19, 2025
dc436d5
remove cstdint
joaosaffran Aug 19, 2025
8353fe0
remove Loc
joaosaffran Aug 19, 2025
f3ecd8a
removing dependency of Object
joaosaffran Aug 20, 2025
8c143ba
removing binary format descriptor range dependency
joaosaffran Aug 20, 2025
a4d77d7
Revert "removing binary format descriptor range dependency"
joaosaffran Aug 20, 2025
19ec1c3
Merge branch 'main' into refactoring/updating-descriptor-range
joaosaffran Aug 29, 2025
182c817
removing binary format descriptor range dependency
joaosaffran Aug 20, 2025
f9d16d2
creating toDescriptorRange and change verifyDescriptorRangeFlag signa…
joaosaffran Aug 29, 2025
42f8f11
adding test and removing string switch
joaosaffran Aug 29, 2025
7ada31b
removing copy
joaosaffran Aug 29, 2025
fa60959
clean up
joaosaffran Aug 30, 2025
e065a82
removing function I thought I needed
joaosaffran Sep 6, 2025
17dbe9f
refactoring to use dxil::ResourceClass for range type
joaosaffran Sep 8, 2025
5c23b7e
adding assert
joaosaffran Sep 8, 2025
1c539f0
changing casting to use proper llvm-casting
joaosaffran Sep 8, 2025
4074ceb
removing unused code
joaosaffran Sep 9, 2025
36afa22
removing assert and adding lastEntry
joaosaffran Sep 10, 2025
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5 changes: 2 additions & 3 deletions clang/lib/Sema/SemaHLSL.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1283,9 +1283,8 @@ bool SemaHLSL::handleRootSignatureElements(
ReportError(Loc, 1, 0xfffffffe);
}

if (!llvm::hlsl::rootsig::verifyDescriptorRangeFlag(
Version, llvm::to_underlying(Clause->Type),
llvm::to_underlying(Clause->Flags)))
if (!llvm::hlsl::rootsig::verifyDescriptorRangeFlag(Version, Clause->Type,
Clause->Flags))
ReportFlagError(Loc);
}
}
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14 changes: 7 additions & 7 deletions llvm/include/llvm/BinaryFormat/DXContainer.h
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Expand Up @@ -192,13 +192,6 @@ enum class RootParameterType : uint32_t {

LLVM_ABI ArrayRef<EnumEntry<RootParameterType>> getRootParameterTypes();

#define DESCRIPTOR_RANGE(Val, Enum) Enum = Val,
enum class DescriptorRangeType : uint32_t {
#include "DXContainerConstants.def"
};

LLVM_ABI ArrayRef<EnumEntry<DescriptorRangeType>> getDescriptorRangeTypes();

#define ROOT_PARAMETER(Val, Enum) \
case Val: \
return true;
Expand All @@ -209,6 +202,13 @@ inline bool isValidParameterType(uint32_t V) {
return false;
}

inline bool isValidRangeType(uint32_t V) {
static_assert(llvm::to_underlying(dxil::ResourceClass::Sampler) == 3,
"dxil::ResourceClass numeric values must match the Root "
"Signature values associated to each class.");
return V <= llvm::to_underlying(dxil::ResourceClass::Sampler);
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I don't think this assert really captures what you want it to here - if we were to add another value to ResourceClass after Sampler this would still be fine but the <= check wouldn't be correct any more. Similarly, if we reordered SRV and UAV for some reason this wouldn't detect it.

A better way to do this would probably be to add a LastEntry to ResourceClass that aliases Sampler, that is:

enum class ResourceClass : uint8_t {
  SRV = 0,
  UAV,
  CBuffer,
  Sampler,
  LastEntry = Sampler,
};

Then we can just check V <= llvm::to_underlying(dxil::ResourceClass::LastEntry) here and we don't need an assert to sanity check the enum. Note that -Wcovered-switch will be fine with this, since the value is indeed covered by the "Sampler" case.

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@bogner Thanks, that make sense. One question, How can I make sure the enum values are still assigned to the correct numbers? Like, SRV must be 0, UAV must be 1 and so on.

We have those tests failing if we change the order of elements in the enum. Is that good enough?

  LLVM :: Analysis/DXILResource/buffer-frombinding.ll
  LLVM :: CodeGen/DirectX/BufferLoad.ll
  LLVM :: CodeGen/DirectX/ContainerData/PSVResources-order.ll
  LLVM :: CodeGen/DirectX/ContainerData/PSVResources.ll
  LLVM :: CodeGen/DirectX/ContainerData/RootSignature-DescriptorTable-AllValidFlagCombinations.ll
  LLVM :: CodeGen/DirectX/ContainerData/RootSignature-DescriptorTable-AllValidFlagCombinationsV1.ll
  LLVM :: CodeGen/DirectX/ContainerData/RootSignature-DescriptorTable.ll
  LLVM :: CodeGen/DirectX/CreateHandle.ll
  LLVM :: CodeGen/DirectX/CreateHandleFromBinding.ll

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Yeah, other than static_assert on each value individually there isn't much we can do here. I think the test coverage is sufficient here.

}

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Since we are using dxil::ResourceClass to represent Root Signature Descriptor Range Type, the numeric numbers associated with each member of dxil::ResourceClass, must match the expected numeric representation for range types in root signature binary representation.

#define SHADER_VISIBILITY(Val, Enum) Enum = Val,
enum class ShaderVisibility : uint32_t {
#include "DXContainerConstants.def"
Expand Down
10 changes: 0 additions & 10 deletions llvm/include/llvm/BinaryFormat/DXContainerConstants.def
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Expand Up @@ -104,16 +104,6 @@ DESCRIPTOR_RANGE_FLAG(0x10000, DescriptorsStaticKeepingBufferBoundsChecks, DESCR
#undef DESCRIPTOR_RANGE_FLAG
#endif // DESCRIPTOR_RANGE_FLAG

// DESCRIPTOR_RANGE(value, name).
#ifdef DESCRIPTOR_RANGE

DESCRIPTOR_RANGE(0, SRV)
DESCRIPTOR_RANGE(1, UAV)
DESCRIPTOR_RANGE(2, CBV)
DESCRIPTOR_RANGE(3, Sampler)
#undef DESCRIPTOR_RANGE
#endif // DESCRIPTOR_RANGE

Comment on lines -107 to -116
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Those are no longer needed, they were replaced by dxil::ResourceClass

#ifdef ROOT_PARAMETER

ROOT_PARAMETER(0, DescriptorTable)
Expand Down
5 changes: 3 additions & 2 deletions llvm/include/llvm/Frontend/HLSL/RootSignatureValidations.h
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Expand Up @@ -30,8 +30,9 @@ LLVM_ABI bool verifyRegisterValue(uint32_t RegisterValue);
LLVM_ABI bool verifyRegisterSpace(uint32_t RegisterSpace);
LLVM_ABI bool verifyRootDescriptorFlag(uint32_t Version, uint32_t FlagsVal);
LLVM_ABI bool verifyRangeType(uint32_t Type);
LLVM_ABI bool verifyDescriptorRangeFlag(uint32_t Version, uint32_t Type,
uint32_t FlagsVal);
LLVM_ABI bool verifyDescriptorRangeFlag(uint32_t Version,
dxil::ResourceClass Type,
dxbc::DescriptorRangeFlags FlagsVal);
LLVM_ABI bool verifyNumDescriptors(uint32_t NumDescriptors);
LLVM_ABI bool verifySamplerFilter(uint32_t Value);
LLVM_ABI bool verifyAddress(uint32_t Address);
Expand Down
15 changes: 12 additions & 3 deletions llvm/include/llvm/MC/DXContainerRootSignature.h
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Expand Up @@ -31,6 +31,15 @@ struct RootDescriptor {
uint32_t Flags;
};

struct DescriptorRange {
dxil::ResourceClass RangeType;
uint32_t NumDescriptors;
uint32_t BaseShaderRegister;
uint32_t RegisterSpace;
uint32_t Flags;
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I decided to keep the flags as uint32_t, since the flags are not mutually exclusive.

uint32_t OffsetInDescriptorsFromTableStart;
};

struct RootParameterInfo {
dxbc::RootParameterType Type;
dxbc::ShaderVisibility Visibility;
Expand All @@ -42,11 +51,11 @@ struct RootParameterInfo {
};

struct DescriptorTable {
SmallVector<dxbc::RTS0::v2::DescriptorRange> Ranges;
SmallVector<dxbc::RTS0::v2::DescriptorRange>::const_iterator begin() const {
SmallVector<DescriptorRange> Ranges;
SmallVector<DescriptorRange>::const_iterator begin() const {
return Ranges.begin();
}
SmallVector<dxbc::RTS0::v2::DescriptorRange>::const_iterator end() const {
SmallVector<DescriptorRange>::const_iterator end() const {
return Ranges.end();
}
};
Expand Down
31 changes: 13 additions & 18 deletions llvm/lib/Frontend/HLSL/RootSignatureMetadata.cpp
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Expand Up @@ -322,23 +322,23 @@ Error MetadataParser::parseDescriptorRange(mcdxbc::DescriptorTable &Table,
if (RangeDescriptorNode->getNumOperands() != 6)
return make_error<InvalidRSMetadataFormat>("Descriptor Range");

dxbc::RTS0::v2::DescriptorRange Range;
mcdxbc::DescriptorRange Range;

std::optional<StringRef> ElementText =
extractMdStringValue(RangeDescriptorNode, 0);

if (!ElementText.has_value())
return make_error<InvalidRSMetadataFormat>("Descriptor Range");

Range.RangeType =
StringSwitch<uint32_t>(*ElementText)
.Case("CBV", to_underlying(dxbc::DescriptorRangeType::CBV))
.Case("SRV", to_underlying(dxbc::DescriptorRangeType::SRV))
.Case("UAV", to_underlying(dxbc::DescriptorRangeType::UAV))
.Case("Sampler", to_underlying(dxbc::DescriptorRangeType::Sampler))
.Default(~0U);

if (Range.RangeType == ~0U)
if (*ElementText == "CBV")
Range.RangeType = dxil::ResourceClass::CBuffer;
else if (*ElementText == "SRV")
Range.RangeType = dxil::ResourceClass::SRV;
else if (*ElementText == "UAV")
Range.RangeType = dxil::ResourceClass::UAV;
else if (*ElementText == "Sampler")
Range.RangeType = dxil::ResourceClass::Sampler;
else
return make_error<GenericRSMetadataError>("Invalid Descriptor Range type.",
RangeDescriptorNode);

Expand Down Expand Up @@ -568,13 +568,7 @@ Error MetadataParser::validateRootSignature(
case dxbc::RootParameterType::DescriptorTable: {
const mcdxbc::DescriptorTable &Table =
RSD.ParametersContainer.getDescriptorTable(Info.Location);
for (const dxbc::RTS0::v2::DescriptorRange &Range : Table) {
if (!hlsl::rootsig::verifyRangeType(Range.RangeType))
DeferredErrs =
joinErrors(std::move(DeferredErrs),
make_error<RootSignatureValidationError<uint32_t>>(
"RangeType", Range.RangeType));
Comment on lines -571 to -576
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Range type should've been verified and converted to an enum by this point, so this check don't make sense anymore.


for (const mcdxbc::DescriptorRange &Range : Table) {
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nit: remove whitespace below this line

if (!hlsl::rootsig::verifyRegisterSpace(Range.RegisterSpace))
DeferredErrs =
joinErrors(std::move(DeferredErrs),
Expand All @@ -588,7 +582,8 @@ Error MetadataParser::validateRootSignature(
"NumDescriptors", Range.NumDescriptors));

if (!hlsl::rootsig::verifyDescriptorRangeFlag(
RSD.Version, Range.RangeType, Range.Flags))
RSD.Version, Range.RangeType,
dxbc::DescriptorRangeFlags(Range.Flags)))
DeferredErrs =
joinErrors(std::move(DeferredErrs),
make_error<RootSignatureValidationError<uint32_t>>(
Expand Down
20 changes: 3 additions & 17 deletions llvm/lib/Frontend/HLSL/RootSignatureValidations.cpp
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Expand Up @@ -51,25 +51,11 @@ bool verifyRootDescriptorFlag(uint32_t Version, uint32_t FlagsVal) {
return (Flags | DataFlags) == DataFlags;
}

bool verifyRangeType(uint32_t Type) {
switch (Type) {
case llvm::to_underlying(dxbc::DescriptorRangeType::CBV):
case llvm::to_underlying(dxbc::DescriptorRangeType::SRV):
case llvm::to_underlying(dxbc::DescriptorRangeType::UAV):
case llvm::to_underlying(dxbc::DescriptorRangeType::Sampler):
return true;
};

return false;
}
Comment on lines -54 to -64
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This check now can be done by the function isValidRangeType, and should be called whenever reading root signature binary data.


bool verifyDescriptorRangeFlag(uint32_t Version, uint32_t Type,
uint32_t FlagsVal) {
bool verifyDescriptorRangeFlag(uint32_t Version, dxil::ResourceClass Type,
dxbc::DescriptorRangeFlags Flags) {
using FlagT = dxbc::DescriptorRangeFlags;
FlagT Flags = FlagT(FlagsVal);

const bool IsSampler =
(Type == llvm::to_underlying(dxbc::DescriptorRangeType::Sampler));
const bool IsSampler = (Type == dxil::ResourceClass::Sampler);

if (Version == 1) {
// Since the metadata is unversioned, we expect to explicitly see the values
Expand Down
3 changes: 2 additions & 1 deletion llvm/lib/MC/DXContainerRootSignature.cpp
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Expand Up @@ -137,7 +137,8 @@ void RootSignatureDesc::write(raw_ostream &OS) const {
llvm::endianness::little);
rewriteOffsetToCurrentByte(BOS, writePlaceholder(BOS));
for (const auto &Range : Table) {
support::endian::write(BOS, Range.RangeType, llvm::endianness::little);
support::endian::write(BOS, static_cast<uint32_t>(Range.RangeType),
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dxil::ResourceClasses are uint8_t by default, so changing its type or casting is required. I opted to cast, since that seems to be the less disruptive option.

llvm::endianness::little);
support::endian::write(BOS, Range.NumDescriptors,
llvm::endianness::little);
support::endian::write(BOS, Range.BaseShaderRegister,
Expand Down
7 changes: 4 additions & 3 deletions llvm/lib/ObjectYAML/DXContainerEmitter.cpp
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Expand Up @@ -313,9 +313,10 @@ Error DXContainerWriter::writeParts(raw_ostream &OS) {
P.RootSignature->Parameters.getOrInsertTable(L);
mcdxbc::DescriptorTable Table;
for (const auto &R : TableYaml.Ranges) {

dxbc::RTS0::v2::DescriptorRange Range;
Range.RangeType = R.RangeType;
assert(dxbc::isValidRangeType(R.RangeType) &&
"Invalid Descriptor Range Type");
Comment on lines +316 to +317
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Once we use enums in the yaml represention this should be impossible to trigger. But I am making it clear here, by adding this assert.

mcdxbc::DescriptorRange Range;
Range.RangeType = dxil::ResourceClass(R.RangeType);
Range.NumDescriptors = R.NumDescriptors;
Range.BaseShaderRegister = R.BaseShaderRegister;
Range.RegisterSpace = R.RegisterSpace;
Expand Down
24 changes: 3 additions & 21 deletions llvm/lib/Target/DirectX/DXILPostOptimizationValidation.cpp
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Expand Up @@ -25,21 +25,6 @@
using namespace llvm;
using namespace llvm::dxil;

static ResourceClass toResourceClass(dxbc::DescriptorRangeType RangeType) {
using namespace dxbc;
switch (RangeType) {
case DescriptorRangeType::SRV:
return ResourceClass::SRV;
case DescriptorRangeType::UAV:
return ResourceClass::UAV;
case DescriptorRangeType::CBV:
return ResourceClass::CBuffer;
case DescriptorRangeType::Sampler:
return ResourceClass::Sampler;
}
llvm_unreachable("Unknown DescriptorRangeType");
}

static ResourceClass toResourceClass(dxbc::RootParameterType Type) {
using namespace dxbc;
switch (Type) {
Expand Down Expand Up @@ -205,16 +190,13 @@ static void validateRootSignature(Module &M,
const mcdxbc::DescriptorTable &Table =
RSD.ParametersContainer.getDescriptorTable(ParamInfo.Location);

for (const dxbc::RTS0::v2::DescriptorRange &Range : Table.Ranges) {
for (const mcdxbc::DescriptorRange &Range : Table.Ranges) {
uint32_t UpperBound =
Range.NumDescriptors == ~0U
? Range.BaseShaderRegister
: Range.BaseShaderRegister + Range.NumDescriptors - 1;
Builder.trackBinding(
toResourceClass(
static_cast<dxbc::DescriptorRangeType>(Range.RangeType)),
Range.RegisterSpace, Range.BaseShaderRegister, UpperBound,
&ParamInfo);
Builder.trackBinding(Range.RangeType, Range.RegisterSpace,
Range.BaseShaderRegister, UpperBound, &ParamInfo);
}
break;
}
Expand Down
5 changes: 3 additions & 2 deletions llvm/lib/Target/DirectX/DXILRootSignature.cpp
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Expand Up @@ -205,8 +205,9 @@ PreservedAnalyses RootSignatureAnalysisPrinter::run(Module &M,
RS.ParametersContainer.getDescriptorTable(Info.Location);
OS << " NumRanges: " << Table.Ranges.size() << "\n";

for (const dxbc::RTS0::v2::DescriptorRange Range : Table) {
OS << " - Range Type: " << Range.RangeType << "\n"
for (const mcdxbc::DescriptorRange &Range : Table) {
OS << " - Range Type: "
<< dxil::getResourceClassName(Range.RangeType) << "\n"
<< " Register Space: " << Range.RegisterSpace << "\n"
<< " Base Shader Register: " << Range.BaseShaderRegister << "\n"
<< " Num Descriptors: " << Range.NumDescriptors << "\n"
Expand Down
4 changes: 2 additions & 2 deletions llvm/test/CodeGen/DirectX/ContainerData/RootSignature-Parameters.ll
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Expand Up @@ -38,13 +38,13 @@ attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
;CHECK-NEXT: - Parameter Type: DescriptorTable
;CHECK-NEXT: Shader Visibility: All
;CHECK-NEXT: NumRanges: 2
;CHECK-NEXT: - Range Type: 0
;CHECK-NEXT: - Range Type: SRV
;CHECK-NEXT: Register Space: 0
;CHECK-NEXT: Base Shader Register: 1
;CHECK-NEXT: Num Descriptors: 1
;CHECK-NEXT: Offset In Descriptors From Table Start: 4294967295
;CHECK-NEXT: Flags: 4
;CHECK-NEXT: - Range Type: 1
;CHECK-NEXT: - Range Type: UAV
;CHECK-NEXT: Register Space: 10
;CHECK-NEXT: Base Shader Register: 1
;CHECK-NEXT: Num Descriptors: 5
Expand Down