[SPIR-V] Emit DebugTypePointer from NonSemantic DI (llvm#109287)

Implementation of DebugTypePointer from
NonSemantic.Shader.DebugInfo.100.

Author: bwlodarcz

llvm/lib/Target/SPIRV/SPIRVEmitNonSemanticDI.cpp

@@ -4,6 +4,7 @@
 #include "SPIRVGlobalRegistry.h"
 #include "SPIRVRegisterInfo.h"
 #include "SPIRVTargetMachine.h"
+#include "SPIRVUtils.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/BinaryFormat/Dwarf.h"
@@ -104,6 +105,7 @@ bool SPIRVEmitNonSemanticDI::emitGlobalDI(MachineFunction &MF) {
   int64_t DwarfVersion = 0;
   int64_t DebugInfoVersion = 0;
   SmallPtrSet<DIBasicType *, 12> BasicTypes;
+  SmallPtrSet<DIDerivedType *, 12> PointerDerivedTypes;
   // Searching through the Module metadata to find nescessary
   // information like DwarfVersion or SourceLanguage
   {
@@ -146,8 +148,21 @@ bool SPIRVEmitNonSemanticDI::emitGlobalDI(MachineFunction &MF) {
           for (DbgVariableRecord &DVR : filterDbgVars(I.getDbgRecordRange())) {
             DILocalVariable *LocalVariable = DVR.getVariable();
             if (auto *BasicType =
-                    dyn_cast<DIBasicType>(LocalVariable->getType()))
+                    dyn_cast<DIBasicType>(LocalVariable->getType())) {
               BasicTypes.insert(BasicType);
+            } else if (auto *DerivedType =
+                           dyn_cast<DIDerivedType>(LocalVariable->getType())) {
+              if (DerivedType->getTag() == dwarf::DW_TAG_pointer_type) {
+                PointerDerivedTypes.insert(DerivedType);
+                // DIBasicType can be unreachable from DbgRecord and only
+                // pointed on from other DI types
+                // DerivedType->getBaseType is null when pointer
+                // is representing a void type
+                if (DerivedType->getBaseType())
+                  BasicTypes.insert(
+                      cast<DIBasicType>(DerivedType->getBaseType()));
+              }
+            }
           }
         }
       }
@@ -206,6 +221,7 @@ bool SPIRVEmitNonSemanticDI::emitGlobalDI(MachineFunction &MF) {
 
     const Register DwarfVersionReg =
         GR->buildConstantInt(DwarfVersion, MIRBuilder, I32Ty, false);
+
     const Register DebugInfoVersionReg =
         GR->buildConstantInt(DebugInfoVersion, MIRBuilder, I32Ty, false);
 
@@ -237,7 +253,6 @@ bool SPIRVEmitNonSemanticDI::emitGlobalDI(MachineFunction &MF) {
         break;
       case dwarf::DW_LANG_Zig:
         SpirvSourceLanguage = SourceLanguage::Zig;
-        break;
       }
 
       const Register SourceLanguageReg =
@@ -255,6 +270,11 @@ bool SPIRVEmitNonSemanticDI::emitGlobalDI(MachineFunction &MF) {
     const Register I32ZeroReg =
         GR->buildConstantInt(0, MIRBuilder, I32Ty, false);
 
+    // We need to store pairs because further instructions reference
+    // the DIBasicTypes and size will be always small so there isn't
+    // need for any kind of map
+    SmallVector<std::pair<const DIBasicType *const, const Register>, 12>
+        BasicTypeRegPairs;
     for (auto *BasicType : BasicTypes) {
       const Register BasicTypeStrReg = EmitOpString(BasicType->getName());
 
@@ -288,11 +308,46 @@ bool SPIRVEmitNonSemanticDI::emitGlobalDI(MachineFunction &MF) {
       const Register AttributeEncodingReg =
           GR->buildConstantInt(AttributeEncoding, MIRBuilder, I32Ty, false);
 
-      [[maybe_unused]]
       const Register BasicTypeReg =
           EmitDIInstruction(SPIRV::NonSemanticExtInst::DebugTypeBasic,
                             {BasicTypeStrReg, ConstIntBitwidthReg,
                              AttributeEncodingReg, I32ZeroReg});
+      BasicTypeRegPairs.emplace_back(BasicType, BasicTypeReg);
+    }
+
+    if (PointerDerivedTypes.size()) {
+      for (const auto *PointerDerivedType : PointerDerivedTypes) {
+
+        assert(PointerDerivedType->getDWARFAddressSpace().has_value());
+        const Register StorageClassReg = GR->buildConstantInt(
+            addressSpaceToStorageClass(
+                PointerDerivedType->getDWARFAddressSpace().value(),
+                *TM->getSubtargetImpl()),
+            MIRBuilder, I32Ty, false);
+
+        // If the Pointer is representing a void type it's getBaseType
+        // is a nullptr
+        const auto *MaybeNestedBasicType =
+            cast_or_null<DIBasicType>(PointerDerivedType->getBaseType());
+        if (MaybeNestedBasicType) {
+          for (const auto &BasicTypeRegPair : BasicTypeRegPairs) {
+            const auto &[DefinedBasicType, BasicTypeReg] = BasicTypeRegPair;
+            if (DefinedBasicType == MaybeNestedBasicType) {
+              [[maybe_unused]]
+              const Register DebugPointerTypeReg = EmitDIInstruction(
+                  SPIRV::NonSemanticExtInst::DebugTypePointer,
+                  {BasicTypeReg, StorageClassReg, I32ZeroReg});
+            }
+          }
+        } else {
+          const Register DebugInfoNoneReg =
+              EmitDIInstruction(SPIRV::NonSemanticExtInst::DebugInfoNone, {});
+          [[maybe_unused]]
+          const Register DebugPointerTypeReg = EmitDIInstruction(
+              SPIRV::NonSemanticExtInst::DebugTypePointer,
+              {DebugInfoNoneReg, StorageClassReg, I32ZeroReg});
+        }
+      }
     }
   }
   return true;

llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp

@@ -436,7 +436,7 @@ void SPIRVModuleAnalysis::processOtherInstrs(const Module &M) {
           namespace NS = SPIRV::NonSemanticExtInst;
           static constexpr int64_t GlobalNonSemanticDITy[] = {
               NS::DebugSource, NS::DebugCompilationUnit, NS::DebugInfoNone,
-              NS::DebugTypeBasic};
+              NS::DebugTypeBasic, NS::DebugTypePointer};
           bool IsGlobalDI = false;
           for (unsigned Idx = 0; Idx < std::size(GlobalNonSemanticDITy); ++Idx)
             IsGlobalDI |= Ins.getImm() == GlobalNonSemanticDITy[Idx];