[DirectX] Set Shader Flag DisableOptimizations.

Disabling optimizations using the option -Od to clang-dxc
results in generation of named metadata "dx.disable_optimizations".

- Detect metadata "dx.disable_optimizations" as part of Metadata
  Analysis pass and set a new bool field
  ModuleMetadatainfo::DisableOptimization accordingly.
- Add DXILMetadataAnalysis as required pass for the pass ShaderFlags
  that sets shader flags mask.
- Set shader flag DisableOptimization based on the value of
  ModuleMetadatainfo::DisableOptimization.

Updated llc-pipeline.ll to reflect changes in output resulting
from addition of Metadata Analysis pass as required by ShaderFlags pass.

Author: bharadwajy

llvm/include/llvm/Analysis/DXILMetadataAnalysis.h

@@ -37,6 +37,7 @@ struct ModuleMetadataInfo {
   Triple::EnvironmentType ShaderProfile{Triple::UnknownEnvironment};
   VersionTuple ValidatorVersion{};
   SmallVector<EntryProperties> EntryPropertyVec{};
+  bool DisableOptimizations{false};
   void print(raw_ostream &OS) const;
 };
 

llvm/lib/Analysis/DXILMetadataAnalysis.cpp

@@ -68,6 +68,22 @@ static ModuleMetadataInfo collectMetadataInfo(Module &M) {
     }
     MMDAI.EntryPropertyVec.push_back(EFP);
   }
+
+  // Set shader flags based on Module properties
+  SmallVector<llvm::Module::ModuleFlagEntry> FlagEntries;
+  M.getModuleFlagsMetadata(FlagEntries);
+  for (const auto &Flag : FlagEntries) {
+    if (Flag.Behavior != Module::ModFlagBehavior::Override)
+      continue;
+    if (Flag.Key->getString().compare("dx.disable_optimizations") == 0) {
+      const auto *V = mdconst::extract<llvm::ConstantInt>(Flag.Val);
+      if (V->isOne()) {
+        MMDAI.DisableOptimizations = true;
+        break;
+      }
+    }
+  }
+
   return MMDAI;
 }
 

llvm/lib/Target/DirectX/DXILShaderFlags.cpp

@@ -85,7 +85,8 @@ void ModuleShaderFlags::updateFunctionFlags(ComputedShaderFlags &CSF,
 }
 
 /// Construct ModuleShaderFlags for module Module M
-void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM) {
+void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM,
+                                   const ModuleMetadataInfo &MMDI) {
   CallGraph CG(M);
 
   // Compute Shader Flags Mask for all functions using post-order visit of SCC
@@ -131,6 +132,9 @@ void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM) {
       // Merge SCCSF with that of F
       FunctionFlags[F].merge(SCCSF);
   }
+
+  // Set shader flags based on Module properties based on module metadata
+  CombinedSFMask.DisableOptimizations = MMDI.DisableOptimizations;
 }
 
 void ComputedShaderFlags::print(raw_ostream &OS) const {
@@ -169,9 +173,10 @@ AnalysisKey ShaderFlagsAnalysis::Key;
 ModuleShaderFlags ShaderFlagsAnalysis::run(Module &M,
                                            ModuleAnalysisManager &AM) {
   DXILResourceTypeMap &DRTM = AM.getResult<DXILResourceTypeAnalysis>(M);
+  const ModuleMetadataInfo MMDI = AM.getResult<DXILMetadataAnalysis>(M);
 
   ModuleShaderFlags MSFI;
-  MSFI.initialize(M, DRTM);
+  MSFI.initialize(M, DRTM, MMDI);
 
   return MSFI;
 }
@@ -201,20 +206,24 @@ PreservedAnalyses ShaderFlagsAnalysisPrinter::run(Module &M,
 bool ShaderFlagsAnalysisWrapper::runOnModule(Module &M) {
   DXILResourceTypeMap &DRTM =
       getAnalysis<DXILResourceTypeWrapperPass>().getResourceTypeMap();
+  const ModuleMetadataInfo MMDI =
+      getAnalysis<DXILMetadataAnalysisWrapperPass>().getModuleMetadata();
 
-  MSFI.initialize(M, DRTM);
+  MSFI.initialize(M, DRTM, MMDI);
   return false;
 }
 
 void ShaderFlagsAnalysisWrapper::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
   AU.addRequiredTransitive<DXILResourceTypeWrapperPass>();
+  AU.addRequired<DXILMetadataAnalysisWrapperPass>();
 }
 
 char ShaderFlagsAnalysisWrapper::ID = 0;
 
 INITIALIZE_PASS_BEGIN(ShaderFlagsAnalysisWrapper, "dx-shader-flag-analysis",
                       "DXIL Shader Flag Analysis", true, true)
 INITIALIZE_PASS_DEPENDENCY(DXILResourceTypeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(DXILMetadataAnalysisWrapperPass)
 INITIALIZE_PASS_END(ShaderFlagsAnalysisWrapper, "dx-shader-flag-analysis",
                     "DXIL Shader Flag Analysis", true, true)

llvm/lib/Target/DirectX/DXILShaderFlags.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_TARGET_DIRECTX_DXILSHADERFLAGS_H
 #define LLVM_TARGET_DIRECTX_DXILSHADERFLAGS_H
 
+#include "llvm/Analysis/DXILMetadataAnalysis.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/Pass.h"
@@ -83,7 +84,8 @@ struct ComputedShaderFlags {
 };
 
 struct ModuleShaderFlags {
-  void initialize(Module &, DXILResourceTypeMap &DRTM);
+  void initialize(Module &, DXILResourceTypeMap &DRTM,
+                  const ModuleMetadataInfo &MMDI);
   const ComputedShaderFlags &getFunctionFlags(const Function *) const;
   const ComputedShaderFlags &getCombinedFlags() const { return CombinedSFMask; }
 

llvm/test/CodeGen/DirectX/ShaderFlags/disable-opt.ll

@@ -0,0 +1,25 @@
+; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+
+target triple = "dxilv1.6-unknown-shadermodel6.6-library"
+
+; CHECK: ; Combined Shader Flags for Module
+; CHECK-NEXT: ; Shader Flags Value: 0x00000001
+
+; CHECK: ; Note: extra DXIL module flags:
+; CHECK-NEXT: ;       D3D11_1_SB_GLOBAL_FLAG_SKIP_OPTIMIZATION
+
+; CHECK: ; Shader Flags for Module Functions
+
+target triple = "dxilv1.6-unknown-shadermodel6.6-library"
+
+; CHECK: ; Function main : 0x00000000
+define void @main() {
+entry:
+  ret void
+}
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 4, !"dx.disable_optimizations", i32 1}
+
+

llvm/test/CodeGen/DirectX/llc-pipeline.ll

@@ -23,8 +23,8 @@
 ; CHECK-NEXT:     Scalarize vector operations
 ; CHECK-NEXT:   DXIL Resource Binding Analysis
 ; CHECK-NEXT:   DXIL resource Information
-; CHECK-NEXT:   DXIL Shader Flag Analysis
 ; CHECK-NEXT:   DXIL Module Metadata analysis
+; CHECK-NEXT:   DXIL Shader Flag Analysis
 ; CHECK-NEXT:   DXIL Translate Metadata
 ; CHECK-NEXT:   DXIL Op Lowering
 ; CHECK-NEXT:   DXIL Prepare Module