[DirectX] Set Shader Flag DisableOptimizations. #123136
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@llvm/pr-subscribers-llvm-analysis @llvm/pr-subscribers-backend-directx Author: S. Bharadwaj Yadavalli (bharadwajy) ChangesDisabling optimizations using the option
NOTE: An alternative implementation that
has been considered. However, Metadata Analysis pass seemed appropriate for detection of metadata relevant to setting the shader flag Closes #112263 Full diff: https://github.com/llvm/llvm-project/pull/123136.diff 6 Files Affected:
diff --git a/llvm/include/llvm/Analysis/DXILMetadataAnalysis.h b/llvm/include/llvm/Analysis/DXILMetadataAnalysis.h
index cb535ac14f1c61..93a926c8991a8c 100644
--- a/llvm/include/llvm/Analysis/DXILMetadataAnalysis.h
+++ b/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;
};
diff --git a/llvm/lib/Analysis/DXILMetadataAnalysis.cpp b/llvm/lib/Analysis/DXILMetadataAnalysis.cpp
index a7f666a3f8b48f..426559c64f8762 100644
--- a/llvm/lib/Analysis/DXILMetadataAnalysis.cpp
+++ b/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;
}
diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
index b1ff975d4dae96..3684411c63bc56 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
+++ b/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;
}
@@ -201,14 +206,17 @@ 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;
@@ -216,5 +224,6 @@ 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)
diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.h b/llvm/lib/Target/DirectX/DXILShaderFlags.h
index e6c6d56402c1a7..abf7cc86259ed8 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.h
+++ b/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; }
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/disable-opt.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/disable-opt.ll
new file mode 100644
index 00000000000000..ee42b5b758ca0c
--- /dev/null
+++ b/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}
+
+
diff --git a/llvm/test/CodeGen/DirectX/llc-pipeline.ll b/llvm/test/CodeGen/DirectX/llc-pipeline.ll
index b0715572494146..03b2150bbc1dc3 100644
--- a/llvm/test/CodeGen/DirectX/llc-pipeline.ll
+++ b/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
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Is the |
I am not aware of module-level metadata Currently, presence of command-line option |
There's a very big difference between |
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.
from module after its presence has been noted in ModuleMetadata Analysis pass. This ensures that this metadata that is not part of DXIL specification is not emitted in the final output. Update disable-opt.ll to verify dx.disable_optimizations metadata is deleted.
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With the changes that delete the metadata |
| // emitted in the final DXIL output, now that its intent is captured in MMDAI, | ||
| // if present. | ||
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| if (NewFlagEntries.size() != FlagEntries.size()) { |
There was a problem hiding this comment.
Do we need to do this here? We have code in DXILPrepare that cleans the module flags.
@bogner, I think the reason the dx.disable_optimizations named metadata wasn't causing issues is because DXIL doesn't use custom module flags at all, so in DXILPrepare we just strip out any non-standard LLVM 3.7 module flags, which will clean this up.
There was a problem hiding this comment.
Do we need to do this here? We have code in DXILPrepare that cleans the module flags.
@bogner, I think the reason the
dx.disable_optimizationsnamed metadata wasn't causing issues is because DXIL doesn't use custom module flags at all, so in DXILPrepare we just strip out any non-standard LLVM 3.7 module flags, which will clean this up.
@llvm-beanz I proposed a PR to decorate shader entry functions with the attribute optnone as an alternative to using dx.disable_optimizations named metadata - per feedback above.
The idea is to eliminate creation of dx.disable_optimizations metadata and key off the optnone attribute on shader entry functions to set the shader flag DisableOptimizations as implemented here with an expectation of converting it to a follow-on PR to #125937.
I'd appreciate feedback on #125937 in this context as well as the preferred choice compared to this PR.
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This looks like it now needs an update to adjust to #125937 landing.
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This is superceded by #126813, right? Please close this if it's no longer relevant. |
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Closing. Superceded by #126813. |
Disabling optimizations using the option
-Odtoclang-dxcresults in generation of named metadata "dx.disable_optimizations" - as tested here.Following changes facilitate setting of Shader Flag
DisableOptimizations.boolfieldModuleMetadatainfo::DisableOptimizationaccordingly.DXILMetadataAnalysisas required pass for the passDXILShaderFlagsthat sets shader flags mask.DisableOptimizationsbased on the value ofModuleMetadatainfo::DisableOptimizations.Added test to verify setting of shader flag
DisableOptimizations.Updated
llc-pipeline.llto reflect changes in output resulting from addition of Metadata Analysis pass as required byDXILShaderFlagspass.NOTE: An alternative implementation that
DXILShaderFlagsbutDXILShaderFlagspasshas been considered. However, Metadata Analysis pass seemed appropriate for detection of metadata relevant to setting the shader flag
DisableOptimizations. Hence this PR.Closes #112263