[llvm] [SPIRV] Emitting DebugSource, DebugCompileUnit (PR #97558)

[Vyacheslav Levytskyy via llvm-commits]

================
@@ -0,0 +1,148 @@
+#include "MCTargetDesc/SPIRVBaseInfo.h"
+#include "SPIRVGlobalRegistry.h"
+#include "SPIRVRegisterInfo.h"
+#include "SPIRVTargetMachine.h"
+#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineOperand.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;
+  SPIRVTargetMachine *TM;
+  SPIRVEmitNonSemanticDI(SPIRVTargetMachine *TM);
+  SPIRVEmitNonSemanticDI();
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+private:
+  bool IsGlobalDIEmitted = false;
+  bool emitGlobalDI(MachineFunction &MF);
+};
+
+void initializeSPIRVEmitNonSemanticDIPass(PassRegistry &);
+
+FunctionPass *createSPIRVEmitNonSemanticDIPass(SPIRVTargetMachine *TM) {
+  return new SPIRVEmitNonSemanticDI(TM);
+}
+} // 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(SPIRVTargetMachine *TM)
+    : MachineFunctionPass(ID), TM(TM) {
+  initializeSPIRVEmitNonSemanticDIPass(*PassRegistry::getPassRegistry());
+}
+
+SPIRVEmitNonSemanticDI::SPIRVEmitNonSemanticDI() : MachineFunctionPass(ID) {
+  initializeSPIRVEmitNonSemanticDIPass(*PassRegistry::getPassRegistry());
+}
+
+bool SPIRVEmitNonSemanticDI::emitGlobalDI(MachineFunction &MF) {
+  MachineModuleInfo &MMI = MF.getMMI();
+  const Module *M = MMI.getModule();
+  NamedMDNode *DbgCu = M->getNamedMetadata("llvm.dbg.cu");
+  if (!DbgCu) {
+    return false;
+  }
+  std::string FilePath;
+  unsigned SourceLanguage;
+  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();
+      SourceLanguage = CompileUnit->getSourceLanguage();
+    }
+  }
+  NamedMDNode *ModuleFlags = M->getNamedMetadata("llvm.module.flags");
+  int64_t DwarfVersion = 0;
+  int64_t DebugInfoVersion = 0;
+  for (auto *Op : ModuleFlags->operands()) {
+    const MDOperand &StrOp = Op->getOperand(1);
+    if (StrOp.equalsStr("Dwarf Version")) {
+      DwarfVersion =
+          cast<ConstantInt>(
+              cast<ConstantAsMetadata>(Op->getOperand(2))->getValue())
+              ->getSExtValue();
+    } else if (StrOp.equalsStr("Debug Info Version")) {
+      DebugInfoVersion =
+          cast<ConstantInt>(
+              cast<ConstantAsMetadata>(Op->getOperand(2))->getValue())
+              ->getSExtValue();
+    }
+  }
+  const SPIRVInstrInfo *TII = TM->getSubtargetImpl()->getInstrInfo();
+  const SPIRVRegisterInfo *TRI = TM->getSubtargetImpl()->getRegisterInfo();
+  const RegisterBankInfo *RBI = TM->getSubtargetImpl()->getRegBankInfo();
+  SPIRVGlobalRegistry *GR = TM->getSubtargetImpl()->getSPIRVGlobalRegistry();
+  MachineRegisterInfo &MRI = MF.getRegInfo();
+  for (MachineBasicBlock &MBB : MF) {
+    MachineIRBuilder MIRBuilder(MBB, MBB.begin());
+
+    MachineInstrBuilder MIB = MIRBuilder.buildInstr(SPIRV::OpString);
+    Register StrReg = MRI.createVirtualRegister(&SPIRV::IDRegClass);
+    MachineOperand StrRegOp = MachineOperand::CreateReg(StrReg, true);
+    MIB.add(StrRegOp);
+    addStringImm(FilePath, MIB);
+
+    const MachineInstr *VoidTyMI =
+        GR->getOrCreateSPIRVType(Type::getVoidTy(M->getContext()), MIRBuilder);
+
+    MIB = MIRBuilder.buildInstr(SPIRV::OpExtInst);
+    Register DebugSourceResIdReg =
+        MRI.createVirtualRegister(&SPIRV::IDRegClass);
+    MIB.addDef(DebugSourceResIdReg);              // Result ID
----------------
VyacheslavLevytskyy wrote:

The call to `assignSPIRVTypeToVReg` helps to relate a newly created virtual register with existing type. Please see `SPIRVGlobalRegistry::getSPIRVTypeForVReg` and please read the comment that starts definition of the `SPIRVGlobalRegistry` class, it's exactly about the subject (VRegToTypeMap, assignSPIRVTypeToVReg, ...).

I unresolve this conversation to be sure that we both review the code again and ensure that the pattern 
```
      LLT LLType = LLT::...(...);
      const SPIRVType *SpvTy = GR->getOrCreate...;
      Register Reg = MRI->createVirtualRegister(&SPIRV::IDRegClass);
      MRI->setType(Reg, LLType);
      GR->assignSPIRVTypeToVReg(SpvTy, Reg, MIRBuilder.getMF());
```
is applied correctly, with `assignSPIRVTypeToVReg` applied to newly created virtual register (`Reg` in the example), not to the SPIR-V Type register. 

https://github.com/llvm/llvm-project/pull/97558