Removed ConsistentBindings from intermediate flags and moved it to DxilShaderFlags instead. This is because 'keep-all' from the other PR relies on this Enum to be serialized; because reflection needs to know if unused resources are preserved.

Nielsbishere · Nielsbishere · commit 6d0531b0a2aa · 2025-11-13T14:47:18.000+01:00
diff --git a/include/dxc/DXIL/DxilConstants.h b/include/dxc/DXIL/DxilConstants.h
@@ -15,6 +15,12 @@
 
 namespace hlsl {
 
+enum class UnusedResourceBinding : uint32_t { Strip, ReserveAll, Count };
+
+static_assert(UnusedResourceBinding::Count <= UnusedResourceBinding(7),
+              "Only 3 bits are reserved for UnusedResourceBinding by HLOptions "
+              "and ShaderFlags");
+
 /* <py>
 import hctdb_instrhelp
 </py> */
diff --git a/include/dxc/DXIL/DxilModule.h b/include/dxc/DXIL/DxilModule.h
@@ -20,6 +20,7 @@
 #include "dxc/DXIL/DxilSignature.h"
 #include "dxc/DXIL/DxilSubobject.h"
 #include "dxc/DXIL/DxilTypeSystem.h"
+#include "dxc/DXIL/DxilConstants.h"
 
 #include <memory>
 #include <string>
@@ -287,8 +288,9 @@ class DxilModule {
   // Intermediate options that do not make it to DXIL
   void SetLegacyResourceReservation(bool legacyResourceReservation);
   bool GetLegacyResourceReservation() const;
-  void SetConsistentBindings(bool consistentBindings);
-  bool GetConsistentBindings() const;
+
+  void SetUnusedResourceBinding(UnusedResourceBinding unusedResourceBinding);
+  UnusedResourceBinding GetUnusedResourceBinding() const;
   void ClearIntermediateOptions();
 
   // Hull and Domain shaders.
@@ -347,8 +349,7 @@ class DxilModule {
   unsigned m_ActiveStreamMask = 0;
 
   enum IntermediateFlags : uint32_t {
-    LegacyResourceReservation = 1 << 0,
-    ConsistentBindings = 1 << 1
+    LegacyResourceReservation = 1 << 0
   };
 
   llvm::LLVMContext &m_Ctx;
@@ -386,6 +387,7 @@ class DxilModule {
   bool m_bUseMinPrecision = true; // use min precision by default;
   bool m_bAllResourcesBound = false;
   bool m_bResMayAlias = false;
+  UnusedResourceBinding m_unusedResourceBinding = UnusedResourceBinding::Strip;
 
   // properties from HLModule that should not make it to the final DXIL
   uint32_t m_IntermediateFlags = 0;
diff --git a/include/dxc/DXIL/DxilShaderFlags.h b/include/dxc/DXIL/DxilShaderFlags.h
@@ -16,6 +16,7 @@
 namespace hlsl {
 class DxilModule;
 struct DxilFunctionProps;
+enum class UnusedResourceBinding : uint32_t;
 }
 
 namespace llvm {
@@ -219,6 +220,14 @@ class ShaderFlags {
   void SetRequiresGroup(bool flag) { m_bRequiresGroup = flag; }
   bool GetRequiresGroup() const { return m_bRequiresGroup; }
 
+  void SetUnusedResourceBinding(UnusedResourceBinding bindings) {
+    m_UnusedResourceBinding = unsigned(bindings);
+  }
+
+  UnusedResourceBinding GetUnusedResourceBinding() {
+    return UnusedResourceBinding(m_UnusedResourceBinding);
+  }
+
 private:
   // Bit: 0
   unsigned
@@ -359,7 +368,9 @@ class ShaderFlags {
   unsigned m_bRequiresGroup : 1; // SHADER_FEATURE_OPT_REQUIRES_GROUP
                                  // (OptFeatureInfo_RequiresGroup)
 
-  uint32_t m_align1 : 23; // align to 64 bit.
+  unsigned m_UnusedResourceBinding : 3;
+
+  uint32_t m_align1 : 20; // align to 64 bit.
 };
 
 } // namespace hlsl
diff --git a/include/dxc/HLSL/HLModule.h b/include/dxc/HLSL/HLModule.h
@@ -54,7 +54,7 @@ struct HLOptions {
         bDisableOptimizations(false), PackingStrategy(0),
         bUseMinPrecision(false), bDX9CompatMode(false), bFXCCompatMode(false),
         bLegacyResourceReservation(false), bForceZeroStoreLifetimes(false),
-        bConsistentBindings(false), unused(0) {}
+        bUnusedResourceBinding(0), unused(0) {}
   uint32_t GetHLOptionsRaw() const;
   void SetHLOptionsRaw(uint32_t data);
   unsigned bDefaultRowMajor : 1;
@@ -70,8 +70,8 @@ struct HLOptions {
   unsigned bLegacyResourceReservation : 1;
   unsigned bForceZeroStoreLifetimes : 1;
   unsigned bResMayAlias : 1;
-  unsigned bConsistentBindings : 1;
-  unsigned unused : 19;
+  unsigned bUnusedResourceBinding : 3;
+  unsigned unused : 17;
 };
 
 typedef std::unordered_map<const llvm::Function *,
diff --git a/include/dxc/Support/HLSLOptions.h b/include/dxc/Support/HLSLOptions.h
@@ -21,6 +21,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Option/ArgList.h"
 
+#include "dxc/DXIL/DxilConstants.h"
 #include "dxc/Support/WinIncludes.h"
 
 #include "dxc/dxcapi.h"
@@ -54,8 +55,6 @@ enum HlslFlags {
   RewriteOption = (1 << 17),
 };
 
-enum class UnusedResourceBinding { Strip, ReserveAll };
-
 enum ID {
   OPT_INVALID = 0, // This is not an option ID.
 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
@@ -229,7 +228,7 @@ class DxcOpts {
   std::string TimeTrace = "";           // OPT_ftime_trace[EQ]
   unsigned TimeTraceGranularity = 500;  // OPT_ftime_trace_granularity_EQ
   bool VerifyDiagnostics = false;       // OPT_verify
-  UnusedResourceBinding UnusedResources =
+  UnusedResourceBinding UnusedResourceBinding =
       UnusedResourceBinding::Strip; // OPT_fhlsl_unused_resource_bindings_EQ
   bool Verbose = false;             // OPT_verbose
 
diff --git a/lib/DXIL/DxilModule.cpp b/lib/DXIL/DxilModule.cpp
@@ -586,14 +586,12 @@ bool DxilModule::GetLegacyResourceReservation() const {
   return (m_IntermediateFlags & LegacyResourceReservation) != 0;
 }
 
-void DxilModule::SetConsistentBindings(bool consistentBindings) {
-  m_IntermediateFlags &= ~ConsistentBindings;
-  if (consistentBindings)
-    m_IntermediateFlags |= ConsistentBindings;
+void DxilModule::SetUnusedResourceBinding(UnusedResourceBinding unusedResourceBinding) {
+  m_unusedResourceBinding = unusedResourceBinding;
 }
 
-bool DxilModule::GetConsistentBindings() const {
-  return (m_IntermediateFlags & ConsistentBindings) != 0;
+UnusedResourceBinding DxilModule::GetUnusedResourceBinding() const {
+  return m_unusedResourceBinding;
 }
 
 void DxilModule::ClearIntermediateOptions() { m_IntermediateFlags = 0; }
@@ -1548,6 +1546,7 @@ void DxilModule::LoadDxilMetadata() {
     m_bUseMinPrecision = !m_ShaderFlags.GetUseNativeLowPrecision();
     m_bDisableOptimizations = m_ShaderFlags.GetDisableOptimizations();
     m_bAllResourcesBound = m_ShaderFlags.GetAllResourcesBound();
+    m_unusedResourceBinding = m_ShaderFlags.GetUnusedResourceBinding();
     m_bResMayAlias = !m_ShaderFlags.GetResMayNotAlias();
   }
 
diff --git a/lib/DXIL/DxilShaderFlags.cpp b/lib/DXIL/DxilShaderFlags.cpp
@@ -47,7 +47,7 @@ ShaderFlags::ShaderFlags()
       m_bAdvancedTextureOps(false), m_bWriteableMSAATextures(false),
       m_bReserved(false), m_bSampleCmpGradientOrBias(false),
       m_bExtendedCommandInfo(false), m_bUsesDerivatives(false),
-      m_bRequiresGroup(false), m_align1(0) {
+      m_bRequiresGroup(false), m_UnusedResourceBinding(0), m_align1(0) {
   // Silence unused field warnings
   (void)m_align1;
 }
@@ -412,6 +412,7 @@ ShaderFlags ShaderFlags::CollectShaderFlags(const Function *F,
   flag.SetUseNativeLowPrecision(!M->GetUseMinPrecision());
   flag.SetDisableOptimizations(M->GetDisableOptimization());
   flag.SetAllResourcesBound(M->GetAllResourcesBound());
+  flag.SetUnusedResourceBinding(M->GetUnusedResourceBinding());
 
   bool hasDouble = false;
   // ddiv dfma drcp d2i d2u i2d u2d.
diff --git a/lib/DxcSupport/HLSLOptions.cpp b/lib/DxcSupport/HLSLOptions.cpp
@@ -870,9 +870,9 @@ int ReadDxcOpts(const OptTable *optionTable, unsigned flagsToInclude,
       Args.getLastArgValue(OPT_fhlsl_unused_resource_bindings_EQ, "strip");
 
   if (UnusedResources == "strip")
-    opts.UnusedResources = UnusedResourceBinding::Strip;
+    opts.UnusedResourceBinding = UnusedResourceBinding::Strip;
   else if (UnusedResources == "reserve-all")
-    opts.UnusedResources = UnusedResourceBinding::ReserveAll;
+    opts.UnusedResourceBinding = UnusedResourceBinding::ReserveAll;
   else {
     errors << "Error: Invalid value for -fhlsl-unused-resource-bindings option "
               "specified ("
diff --git a/lib/HLSL/DxilCondenseResources.cpp b/lib/HLSL/DxilCondenseResources.cpp
@@ -550,7 +550,7 @@ class DxilLowerCreateHandleForLib : public ModulePass {
     ResourceRegisterAllocator.GatherReservedRegisters(DM);
 
     // Remove unused resources.
-    if (!DM.GetConsistentBindings())
+    if (DM.GetUnusedResourceBinding() == UnusedResourceBinding::Strip)
       bChanged |= DM.RemoveResourcesWithUnusedSymbols();
 
     unsigned newResources = DM.GetCBuffers().size() + DM.GetUAVs().size() +
@@ -562,7 +562,7 @@ class DxilLowerCreateHandleForLib : public ModulePass {
     {
       DxilValueCache *DVC = &getAnalysis<DxilValueCache>();
       bool bLocalChanged = LegalizeResources(M, DVC);
-      if (bLocalChanged && !DM.GetConsistentBindings()) {
+      if (bLocalChanged && DM.GetUnusedResourceBinding() == UnusedResourceBinding::Strip) {
         // Remove unused resources.
         bChanged |= DM.RemoveResourcesWithUnusedSymbols();
       }
@@ -571,7 +571,7 @@ class DxilLowerCreateHandleForLib : public ModulePass {
 
     bChanged |= ResourceRegisterAllocator.AllocateRegisters(DM);
 
-    if (DM.GetConsistentBindings())
+    if (DM.GetUnusedResourceBinding() == UnusedResourceBinding::ReserveAll)
       bChanged |= DM.RemoveResourcesWithUnusedSymbols();
 
     // Fill in top-level CBuffer variable usage bit
diff --git a/lib/HLSL/DxilGenerationPass.cpp b/lib/HLSL/DxilGenerationPass.cpp
@@ -155,7 +155,8 @@ void InitDxilModuleFromHLModule(HLModule &H, DxilModule &M, bool HasDebugInfo) {
   // bool m_bDisableOptimizations;
   M.SetDisableOptimization(H.GetHLOptions().bDisableOptimizations);
   M.SetLegacyResourceReservation(H.GetHLOptions().bLegacyResourceReservation);
-  M.SetConsistentBindings(H.GetHLOptions().bConsistentBindings);
+  M.SetUnusedResourceBinding(
+      UnusedResourceBinding(H.GetHLOptions().bUnusedResourceBinding));
   // bool m_bDisableMathRefactoring;
   // bool m_bEnableDoublePrecision;
   // bool m_bEnableDoubleExtensions;
diff --git a/lib/HLSL/HLModule.cpp b/lib/HLSL/HLModule.cpp
@@ -232,12 +232,12 @@ namespace {
 template <typename TResource>
 bool RemoveResource(std::vector<std::unique_ptr<TResource>> &vec,
                     GlobalVariable *pVariable, bool keepAllocated,
-                    bool consistentBindings) {
+                    UnusedResourceBinding unusedResourceBinding) {
   for (auto p = vec.begin(), e = vec.end(); p != e; ++p) {
     if ((*p)->GetGlobalSymbol() != pVariable)
       continue;
 
-    if ((keepAllocated && (*p)->IsAllocated()) || consistentBindings) {
+    if ((keepAllocated && (*p)->IsAllocated()) || unusedResourceBinding == UnusedResourceBinding::ReserveAll) {
       // Keep the resource, but it has no more symbol.
       (*p)->SetGlobalSymbol(UndefValue::get(pVariable->getType()));
     } else {
@@ -264,22 +264,19 @@ void HLModule::RemoveGlobal(llvm::GlobalVariable *GV) {
   // register range from being allocated to other resources.
   bool keepAllocated = GetHLOptions().bLegacyResourceReservation;
 
-  // Consistent bindings are different than -flegacy-resource-reservation;
-  // We need the IDs to stay the same, but it's fine to remove unused registers.
-  // It's actually wanted, because that allows us to know what registers are
-  // optimized out.
-  bool consistentBindings = GetHLOptions().bConsistentBindings;
+  UnusedResourceBinding unusedResourceBinding =
+      UnusedResourceBinding(GetHLOptions().bUnusedResourceBinding);
 
   // This could be considerably faster - check variable type to see which
   // resource type this is rather than scanning all lists, and look for
   // usage and removal patterns.
-  if (RemoveResource(m_CBuffers, GV, keepAllocated, consistentBindings))
+  if (RemoveResource(m_CBuffers, GV, keepAllocated, unusedResourceBinding))
     return;
-  if (RemoveResource(m_SRVs, GV, keepAllocated, consistentBindings))
+  if (RemoveResource(m_SRVs, GV, keepAllocated, unusedResourceBinding))
     return;
-  if (RemoveResource(m_UAVs, GV, keepAllocated, consistentBindings))
+  if (RemoveResource(m_UAVs, GV, keepAllocated, unusedResourceBinding))
     return;
-  if (RemoveResource(m_Samplers, GV, keepAllocated, consistentBindings))
+  if (RemoveResource(m_Samplers, GV, keepAllocated, unusedResourceBinding))
     return;
   // TODO: do m_TGSMVariables and m_StreamOutputs need maintenance?
 }
diff --git a/tools/clang/include/clang/Frontend/CodeGenOptions.h b/tools/clang/include/clang/Frontend/CodeGenOptions.h
@@ -187,8 +187,9 @@ class CodeGenOptions : public CodeGenOptionsBase {
   bool HLSLOnlyWarnOnUnrollFail = false;
   /// Whether use legacy resource reservation.
   bool HLSLLegacyResourceReservation = false;
-  /// Whether to keep bindings consistent even if optimized out.
-  bool HLSLConsistentBindings = false;
+  /// How to handle unused resource bindings.
+  hlsl::UnusedResourceBinding HLSLUnusedResourceBinding =
+      hlsl::UnusedResourceBinding::Strip;
   /// Set [branch] on every if.
   bool HLSLPreferControlFlow = false;
   /// Set [flatten] on every if.
diff --git a/tools/clang/lib/CodeGen/CGHLSLMS.cpp b/tools/clang/lib/CodeGen/CGHLSLMS.cpp
@@ -400,7 +400,7 @@ CGMSHLSLRuntime::CGMSHLSLRuntime(CodeGenModule &CGM)
   opts.PackingStrategy = CGM.getCodeGenOpts().HLSLSignaturePackingStrategy;
   opts.bLegacyResourceReservation =
       CGM.getCodeGenOpts().HLSLLegacyResourceReservation;
-  opts.bConsistentBindings = CGM.getCodeGenOpts().HLSLConsistentBindings;
+  opts.bUnusedResourceBinding = unsigned(CGM.getCodeGenOpts().HLSLUnusedResourceBinding);
   opts.bForceZeroStoreLifetimes =
       CGM.getCodeGenOpts().HLSLForceZeroStoreLifetimes;
 
diff --git a/tools/clang/tools/dxcompiler/dxcompilerobj.cpp b/tools/clang/tools/dxcompiler/dxcompilerobj.cpp
@@ -1595,8 +1595,7 @@ class DxcCompiler : public IDxcCompiler3,
     compiler.getCodeGenOpts().HLSLAvoidControlFlow = Opts.AvoidFlowControl;
     compiler.getCodeGenOpts().HLSLLegacyResourceReservation =
         Opts.LegacyResourceReservation;
-    compiler.getCodeGenOpts().HLSLConsistentBindings =
-        Opts.UnusedResources == hlsl::options::UnusedResourceBinding::ReserveAll;
+    compiler.getCodeGenOpts().HLSLUnusedResourceBinding = Opts.UnusedResourceBinding;
     compiler.getCodeGenOpts().HLSLDefines = defines;
     compiler.getCodeGenOpts().HLSLPreciseOutputs = Opts.PreciseOutputs;
     compiler.getCodeGenOpts().MainFileName = pMainFile;

Original file line number	Diff line number	Diff line change
`@@ -586,14 +586,12 @@ bool DxilModule::GetLegacyResourceReservation() const {`
`586`	`586`	`return (m_IntermediateFlags & LegacyResourceReservation) != 0;`
`587`	`587`	`}`
`588`	`588`
`589`		`-void DxilModule::SetConsistentBindings(bool consistentBindings) {`
`590`		`- m_IntermediateFlags &= ~ConsistentBindings;`
`591`		`- if (consistentBindings)`
`592`		`- m_IntermediateFlags \|= ConsistentBindings;`
	`589`	`+void DxilModule::SetUnusedResourceBinding(UnusedResourceBinding unusedResourceBinding) {`
	`590`	`+ m_unusedResourceBinding = unusedResourceBinding;`
`593`	`591`	`}`
`594`	`592`
`595`		`-bool DxilModule::GetConsistentBindings() const {`
`596`		`- return (m_IntermediateFlags & ConsistentBindings) != 0;`
	`593`	`+UnusedResourceBinding DxilModule::GetUnusedResourceBinding() const {`
	`594`	`+ return m_unusedResourceBinding;`
`597`	`595`	`}`
`598`	`596`
`599`	`597`	`void DxilModule::ClearIntermediateOptions() { m_IntermediateFlags = 0; }`
`@@ -1548,6 +1546,7 @@ void DxilModule::LoadDxilMetadata() {`
`1548`	`1546`	`m_bUseMinPrecision = !m_ShaderFlags.GetUseNativeLowPrecision();`
`1549`	`1547`	`m_bDisableOptimizations = m_ShaderFlags.GetDisableOptimizations();`
`1550`	`1548`	`m_bAllResourcesBound = m_ShaderFlags.GetAllResourcesBound();`
	`1549`	`+ m_unusedResourceBinding = m_ShaderFlags.GetUnusedResourceBinding();`
`1551`	`1550`	`m_bResMayAlias = !m_ShaderFlags.GetResMayNotAlias();`
`1552`	`1551`	`}`
`1553`	`1552`