[llvm] [SPIRV] Added new stub pass for NonSemantic DI (PR #97042)

[via llvm-commits]

https://github.com/bwlodarcz created https://github.com/llvm/llvm-project/pull/97042

The commit adds new empty pass for emission of NonSemantic.Shader.DebugInfo.100 instructions.
The pass is a basis for future development and can be (and likely will be) a subject of change.
In addition to that there is additional unused function which main purpose is to be basis of accessing global metadata which is inaccessible in MIR. Accessing such metadata is necessary for emitting such instructions like DebugCompilationUnit or DebugSource.

>From cd6da102610a9ece6277706c3fdd95332fbda079 Mon Sep 17 00:00:00 2001
From: "Wlodarczyk, Bertrand" <bertrand.wlodarczyk at intel.com>
Date: Fri, 28 Jun 2024 13:17:42 +0200
Subject: [PATCH] [SPIRV] Added new stub pass for NonSemantic DI

The commit adds new empty pass for emission of
NonSemantic.Shader.DebugInfo.100 instructions.
The pass is a basis for future development and
can be (and likely will be) a subject of change.
In addition to that there is additional unused function
which main purpose is to be basis of accessing global
metadata which is inaccessible in MIR. Accessing such
metadata is necessary for emitting such instructions
like DebugCompilationUnit or DebugSource.
---
 llvm/lib/Target/SPIRV/CMakeLists.txt          |  1 +
 llvm/lib/Target/SPIRV/SPIRV.h                 |  2 +
 .../Target/SPIRV/SPIRVEmitNonSemanticDI.cpp   | 55 +++++++++++++++++++
 llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp  |  1 +
 4 files changed, 59 insertions(+)
 create mode 100644 llvm/lib/Target/SPIRV/SPIRVEmitNonSemanticDI.cpp

diff --git a/llvm/lib/Target/SPIRV/CMakeLists.txt b/llvm/lib/Target/SPIRV/CMakeLists.txt
index 14647e92f5d08..5f8aea5fc8d84 100644
--- a/llvm/lib/Target/SPIRV/CMakeLists.txt
+++ b/llvm/lib/Target/SPIRV/CMakeLists.txt
@@ -40,6 +40,7 @@ add_llvm_target(SPIRVCodeGen
   SPIRVSubtarget.cpp
   SPIRVTargetMachine.cpp
   SPIRVUtils.cpp
+  SPIRVEmitNonSemanticDI.cpp
 
   LINK_COMPONENTS
   Analysis
diff --git a/llvm/lib/Target/SPIRV/SPIRV.h b/llvm/lib/Target/SPIRV/SPIRV.h
index e597a1dc8dc06..c32bf6f5a863d 100644
--- a/llvm/lib/Target/SPIRV/SPIRV.h
+++ b/llvm/lib/Target/SPIRV/SPIRV.h
@@ -26,6 +26,7 @@ FunctionPass *createSPIRVRegularizerPass();
 FunctionPass *createSPIRVPreLegalizerPass();
 FunctionPass *createSPIRVPostLegalizerPass();
 ModulePass *createSPIRVEmitIntrinsicsPass(SPIRVTargetMachine *TM);
+MachineFunctionPass *createSPIRVEmitNonSemanticDIPass();
 InstructionSelector *
 createSPIRVInstructionSelector(const SPIRVTargetMachine &TM,
                                const SPIRVSubtarget &Subtarget,
@@ -36,6 +37,7 @@ void initializeSPIRVConvergenceRegionAnalysisWrapperPassPass(PassRegistry &);
 void initializeSPIRVPreLegalizerPass(PassRegistry &);
 void initializeSPIRVPostLegalizerPass(PassRegistry &);
 void initializeSPIRVEmitIntrinsicsPass(PassRegistry &);
+void initializeSPIRVEmitNonSemanticDIPass(PassRegistry &);
 } // namespace llvm
 
 #endif // LLVM_LIB_TARGET_SPIRV_SPIRV_H
diff --git a/llvm/lib/Target/SPIRV/SPIRVEmitNonSemanticDI.cpp b/llvm/lib/Target/SPIRV/SPIRVEmitNonSemanticDI.cpp
new file mode 100644
index 0000000000000..5b938047025d1
--- /dev/null
+++ b/llvm/lib/Target/SPIRV/SPIRVEmitNonSemanticDI.cpp
@@ -0,0 +1,55 @@
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/PassRegistry.h"
+#include "llvm/Support/Casting.h"
+
+namespace llvm {
+struct SPIRVEmitNonSemanticDI : public MachineFunctionPass {
+  static char ID;
+  SPIRVEmitNonSemanticDI();
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+};
+
+void initializeSPIRVEmitNonSemanticDIPass(PassRegistry &);
+
+FunctionPass *createSPIRVEmitNonSemanticDIPass() {
+  return new SPIRVEmitNonSemanticDI();
+}
+} // namespace llvm
+
+using namespace llvm;
+
+INITIALIZE_PASS(SPIRVEmitNonSemanticDI, "spirv-nonsemantic-debug-info",
+                "SPIRV NonSemantic.Shader.DebugInfo.100 emitter", false, false)
+
+char SPIRVEmitNonSemanticDI::ID = 0;
+
+SPIRVEmitNonSemanticDI::SPIRVEmitNonSemanticDI() : MachineFunctionPass(ID) {
+  initializeSPIRVEmitNonSemanticDIPass(*PassRegistry::getPassRegistry());
+}
+
+[[maybe_unused]]
+static void findCompileUnitDI(const MachineFunction &MF) {
+  MachineModuleInfo &MMI = MF.getMMI();
+  const Module *M = MMI.getModule();
+  NamedMDNode *DbgCu = M->getNamedMetadata("llvm.dbg.cu");
+  std::string FilePath;
+  if (DbgCu) {
+    unsigned NumOp = DbgCu->getNumOperands();
+    if (NumOp) {
+      if (const auto *CompileUnit =
+              dyn_cast<DICompileUnit>(DbgCu->getOperand(0))) {
+        DIFile *File = CompileUnit->getFile();
+        FilePath = ((File->getDirectory() + "/" + File->getFilename())).str();
+      }
+    }
+  }
+}
+
+bool SPIRVEmitNonSemanticDI::runOnMachineFunction(MachineFunction &MF) {
+  return false;
+}
diff --git a/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp b/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp
index 52fc6f33b4ef1..ee71190bc02ff 100644
--- a/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp
@@ -199,6 +199,7 @@ void SPIRVPassConfig::addPreLegalizeMachineIR() {
 bool SPIRVPassConfig::addLegalizeMachineIR() {
   addPass(new Legalizer());
   addPass(createSPIRVPostLegalizerPass());
+  addPass(createSPIRVEmitNonSemanticDIPass());
   return false;
 }