-keep-all-resources option to preserve optimized-out resources in DXIL reflection

include/dxc/DXIL/DxilModule.h

@@ -287,6 +287,8 @@ class DxilModule {
   // Intermediate options that do not make it to DXIL
   void SetLegacyResourceReservation(bool legacyResourceReservation);
   bool GetLegacyResourceReservation() const;
+  void SetKeepAllResources(bool keepAllResources);
+  bool GetKeepAllResources() const;
   void ClearIntermediateOptions();
 
   // Hull and Domain shaders.
@@ -346,6 +348,8 @@ class DxilModule {
 
   enum IntermediateFlags : uint32_t {
     LegacyResourceReservation = 1 << 0,
+    KeepAllResources =
+        1 << 2 // To be compatible with ConsistentBindings in different PR
   };
 
   llvm::LLVMContext &m_Ctx;

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),
-        unused(0) {}
+        bKeepAllResources(false), unused(0) {}
   uint32_t GetHLOptionsRaw() const;
   void SetHLOptionsRaw(uint32_t data);
   unsigned bDefaultRowMajor : 1;
@@ -70,7 +70,8 @@ struct HLOptions {
   unsigned bLegacyResourceReservation : 1;
   unsigned bForceZeroStoreLifetimes : 1;
   unsigned bResMayAlias : 1;
-  unsigned unused : 19;
+  unsigned bKeepAllResources : 1;
+  unsigned unused : 18;
 };
 
 typedef std::unordered_map<const llvm::Function *,

include/dxc/Support/HLSLOptions.h

@@ -227,6 +227,7 @@ class DxcOpts {
   std::string TimeTrace = "";           // OPT_ftime_trace[EQ]
   unsigned TimeTraceGranularity = 500;  // OPT_ftime_trace_granularity_EQ
   bool VerifyDiagnostics = false;       // OPT_verify
+  bool KeepAllResources = false;        // OPT_keep_all_resources
 
   // Optimization pass enables, disables and selects
   OptimizationToggles

include/dxc/Support/HLSLOptions.td

@@ -564,6 +564,9 @@ def getprivate : JoinedOrSeparate<["-", "/"], "getprivate">, Flags<[DriverOption
 def nologo : Flag<["-", "/"], "nologo">, Group<hlslcore_Group>, Flags<[DriverOption, HelpHidden]>,
   HelpText<"Suppress copyright message">;
 
+def keep_all_resources : Flag<["-", "/"], "keep-all-resources">, Group<hlslcomp_Group>, Flags<[CoreOption]>,
+  HelpText<"Keep even optimized out resources for dxil reflection purposes.">;
+
 //////////////////////////////////////////////////////////////////////////////
 // Rewriter Options
 

lib/DXIL/DxilModule.cpp

@@ -586,6 +586,16 @@ bool DxilModule::GetLegacyResourceReservation() const {
   return (m_IntermediateFlags & LegacyResourceReservation) != 0;
 }
 
+void DxilModule::SetKeepAllResources(bool keepAllResources) {
+  m_IntermediateFlags &= ~KeepAllResources;
+  if (keepAllResources)
+    m_IntermediateFlags |= KeepAllResources;
+}
+
+bool DxilModule::GetKeepAllResources() const {
+  return (m_IntermediateFlags & KeepAllResources) != 0;
+}
+
 void DxilModule::ClearIntermediateOptions() { m_IntermediateFlags = 0; }
 
 unsigned DxilModule::GetInputControlPointCount() const {

lib/DxcSupport/HLSLOptions.cpp

@@ -871,6 +871,10 @@ int ReadDxcOpts(const OptTable *optionTable, unsigned flagsToInclude,
   opts.TimeReport = Args.hasFlag(OPT_ftime_report, OPT_INVALID, false);
   opts.TimeTrace = Args.hasFlag(OPT_ftime_trace, OPT_INVALID, false) ? "-" : "";
   opts.VerifyDiagnostics = Args.hasFlag(OPT_verify, OPT_INVALID, false);
+
+  opts.KeepAllResources =
+      Args.hasFlag(OPT_keep_all_resources, OPT_INVALID, false);
+
   if (Args.hasArg(OPT_ftime_trace_EQ))
     opts.TimeTrace = Args.getLastArgValue(OPT_ftime_trace_EQ);
   if (Arg *A = Args.getLastArg(OPT_ftime_trace_granularity_EQ)) {

lib/HLSL/DxilCondenseResources.cpp

@@ -550,7 +550,8 @@ class DxilLowerCreateHandleForLib : public ModulePass {
     ResourceRegisterAllocator.GatherReservedRegisters(DM);
 
     // Remove unused resources.
-    DM.RemoveResourcesWithUnusedSymbols();
+    if (!DM.GetKeepAllResources())
+      DM.RemoveResourcesWithUnusedSymbols();
 
     unsigned newResources = DM.GetCBuffers().size() + DM.GetUAVs().size() +
                             DM.GetSRVs().size() + DM.GetSamplers().size();
@@ -564,7 +565,9 @@ class DxilLowerCreateHandleForLib : public ModulePass {
       bool bLocalChanged = LegalizeResources(M, DVC);
       if (bLocalChanged) {
         // Remove unused resources.
-        DM.RemoveResourcesWithUnusedSymbols();
+
+        if (!DM.GetKeepAllResources())
+          DM.RemoveResourcesWithUnusedSymbols();
       }
       bChanged |= bLocalChanged;
     }
@@ -2122,6 +2125,15 @@ void DxilLowerCreateHandleForLib::ReplaceResourceUserWithHandle(
 void DxilLowerCreateHandleForLib::TranslateDxilResourceUses(
     DxilResourceBase &res) {
   OP *hlslOP = m_DM->GetOP();
+
+  Value *GV = res.GetGlobalSymbol();
+
+  if (isa<UndefValue>(GV))
+    return;
+
+  DXASSERT(isa<GlobalValue>(GV), "DxilLowerCreateHandleForLib cannot deal with "
+                                 "resources that aren't GlobalValue.");
+
   // Generate createHandleFromBinding for sm66 and later.
   bool bCreateFromBinding = m_DM->GetShaderModel()->IsSM66Plus();
   OP::OpCode createOp = bCreateFromBinding ? OP::OpCode::CreateHandleFromBinding
@@ -2149,10 +2161,6 @@ void DxilLowerCreateHandleForLib::TranslateDxilResourceUses(
 
   Value *isUniformRes = hlslOP->GetI1Const(0);
 
-  Value *GV = res.GetGlobalSymbol();
-  DXASSERT(isa<GlobalValue>(GV),
-           "DxilLowerCreateHandleForLib cannot deal with unused resources.");
-
   Module *pM = m_DM->GetModule();
   // TODO: add debug info to create handle.
   DIVariable *DIV = nullptr;

lib/HLSL/DxilGenerationPass.cpp

@@ -155,6 +155,7 @@ void InitDxilModuleFromHLModule(HLModule &H, DxilModule &M, bool HasDebugInfo) {
   // bool m_bDisableOptimizations;
   M.SetDisableOptimization(H.GetHLOptions().bDisableOptimizations);
   M.SetLegacyResourceReservation(H.GetHLOptions().bLegacyResourceReservation);
+  M.SetKeepAllResources(H.GetHLOptions().bKeepAllResources);
   // bool m_bDisableMathRefactoring;
   // bool m_bEnableDoublePrecision;
   // bool m_bEnableDoubleExtensions;

lib/HLSL/HLModule.cpp

@@ -231,12 +231,13 @@ void HLModule::RemoveFunction(llvm::Function *F) {
 namespace {
 template <typename TResource>
 bool RemoveResource(std::vector<std::unique_ptr<TResource>> &vec,
-                    GlobalVariable *pVariable, bool keepAllocated) {
+                    GlobalVariable *pVariable, bool keepAllocated,
+                    bool keepAllResources) {
   for (auto p = vec.begin(), e = vec.end(); p != e; ++p) {
     if ((*p)->GetGlobalSymbol() != pVariable)
       continue;
 
-    if (keepAllocated && (*p)->IsAllocated()) {
+    if ((keepAllocated && (*p)->IsAllocated()) || keepAllResources) {
       // Keep the resource, but it has no more symbol.
       (*p)->SetGlobalSymbol(UndefValue::get(pVariable->getType()));
     } else {
@@ -262,16 +263,20 @@ void HLModule::RemoveGlobal(llvm::GlobalVariable *GV) {
   // register range from being allocated to other resources.
   bool keepAllocated = GetHLOptions().bLegacyResourceReservation;
 
+  // Keep all resources is for reflection purposes to simulate -Od with -spirv
+  // for dxil.
+  bool keepAllResources = GetHLOptions().bKeepAllResources;
+
   // 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))
+  if (RemoveResource(m_CBuffers, GV, keepAllocated, keepAllResources))
     return;
-  if (RemoveResource(m_SRVs, GV, keepAllocated))
+  if (RemoveResource(m_SRVs, GV, keepAllocated, keepAllResources))
     return;
-  if (RemoveResource(m_UAVs, GV, keepAllocated))
+  if (RemoveResource(m_UAVs, GV, keepAllocated, keepAllResources))
     return;
-  if (RemoveResource(m_Samplers, GV, keepAllocated))
+  if (RemoveResource(m_Samplers, GV, keepAllocated, keepAllResources))
     return;
   // TODO: do m_TGSMVariables and m_StreamOutputs need maintenance?
 }

tools/clang/include/clang/Frontend/CodeGenOptions.h

@@ -187,6 +187,8 @@ class CodeGenOptions : public CodeGenOptionsBase {
   bool HLSLOnlyWarnOnUnrollFail = false;
   /// Whether use legacy resource reservation.
   bool HLSLLegacyResourceReservation = false;
+  /// Whether to keep bindings even if they're optimized out.
+  bool HLSLKeepAllResources = false;
   /// Set [branch] on every if.
   bool HLSLPreferControlFlow = false;
   /// Set [flatten] on every if.

tools/clang/lib/CodeGen/CGHLSLMS.cpp

@@ -400,6 +400,7 @@ CGMSHLSLRuntime::CGMSHLSLRuntime(CodeGenModule &CGM)
   opts.PackingStrategy = CGM.getCodeGenOpts().HLSLSignaturePackingStrategy;
   opts.bLegacyResourceReservation =
       CGM.getCodeGenOpts().HLSLLegacyResourceReservation;
+  opts.bKeepAllResources = CGM.getCodeGenOpts().HLSLKeepAllResources;
   opts.bForceZeroStoreLifetimes =
       CGM.getCodeGenOpts().HLSLForceZeroStoreLifetimes;
 

tools/clang/tools/dxcompiler/dxcompilerobj.cpp

@@ -1602,6 +1602,7 @@ class DxcCompiler : public IDxcCompiler3,
     compiler.getCodeGenOpts().HLSLAvoidControlFlow = Opts.AvoidFlowControl;
     compiler.getCodeGenOpts().HLSLLegacyResourceReservation =
         Opts.LegacyResourceReservation;
+    compiler.getCodeGenOpts().HLSLKeepAllResources = Opts.KeepAllResources;
     compiler.getCodeGenOpts().HLSLDefines = defines;
     compiler.getCodeGenOpts().HLSLPreciseOutputs = Opts.PreciseOutputs;
     compiler.getCodeGenOpts().MainFileName = pMainFile;