an initial version of module analysis without explicitly built dependency graph

Author: VyacheslavLevytskyy

llvm/lib/Target/SPIRV/SPIRVAsmPrinter.cpp

@@ -274,7 +274,7 @@ void SPIRVAsmPrinter::emitInstruction(const MachineInstr *MI) {
 }
 
 void SPIRVAsmPrinter::outputModuleSection(SPIRV::ModuleSectionType MSType) {
-  for (MachineInstr *MI : MAI->getMSInstrs(MSType))
+  for (const MachineInstr *MI : MAI->getMSInstrs(MSType))
     outputInstruction(MI);
 }
 
@@ -326,7 +326,7 @@ void SPIRVAsmPrinter::outputOpMemoryModel() {
 void SPIRVAsmPrinter::outputEntryPoints() {
   // Find all OpVariable IDs with required StorageClass.
   DenseSet<Register> InterfaceIDs;
-  for (MachineInstr *MI : MAI->GlobalVarList) {
+  for (const MachineInstr *MI : MAI->GlobalVarList) {
     assert(MI->getOpcode() == SPIRV::OpVariable);
     auto SC = static_cast<SPIRV::StorageClass::StorageClass>(
         MI->getOperand(2).getImm());
@@ -336,14 +336,14 @@ void SPIRVAsmPrinter::outputEntryPoints() {
     // declaring all global variables referenced by the entry point call tree.
     if (ST->isAtLeastSPIRVVer(VersionTuple(1, 4)) ||
         SC == SPIRV::StorageClass::Input || SC == SPIRV::StorageClass::Output) {
-      MachineFunction *MF = MI->getMF();
+      const MachineFunction *MF = MI->getMF();
       Register Reg = MAI->getRegisterAlias(MF, MI->getOperand(0).getReg());
       InterfaceIDs.insert(Reg);
     }
   }
 
   // Output OpEntryPoints adding interface args to all of them.
-  for (MachineInstr *MI : MAI->getMSInstrs(SPIRV::MB_EntryPoints)) {
+  for (const MachineInstr *MI : MAI->getMSInstrs(SPIRV::MB_EntryPoints)) {
     SPIRVMCInstLower MCInstLowering;
     MCInst TmpInst;
     MCInstLowering.lower(MI, TmpInst, MAI);
@@ -381,9 +381,8 @@ void SPIRVAsmPrinter::outputGlobalRequirements() {
 
 void SPIRVAsmPrinter::outputExtFuncDecls() {
   // Insert OpFunctionEnd after each declaration.
-  SmallVectorImpl<MachineInstr *>::iterator
-      I = MAI->getMSInstrs(SPIRV::MB_ExtFuncDecls).begin(),
-      E = MAI->getMSInstrs(SPIRV::MB_ExtFuncDecls).end();
+  auto I = MAI->getMSInstrs(SPIRV::MB_ExtFuncDecls).begin(),
+       E = MAI->getMSInstrs(SPIRV::MB_ExtFuncDecls).end();
   for (; I != E; ++I) {
     outputInstruction(*I);
     if ((I + 1) == E || (*(I + 1))->getOpcode() == SPIRV::OpFunction)

llvm/lib/Target/SPIRV/SPIRVCallLowering.cpp

@@ -418,6 +418,7 @@ bool SPIRVCallLowering::lowerFormalArguments(MachineIRBuilder &MIRBuilder,
                                .addImm(FuncControl)
                                .addUse(GR->getSPIRVTypeID(FuncTy));
   GR->recordFunctionDefinition(&F, &MB.getInstr()->getOperand(0));
+  GR->addGlobalObject(&F, &MIRBuilder.getMF(), FuncVReg);
 
   // Add OpFunctionParameter instructions
   int i = 0;
@@ -431,6 +432,7 @@ bool SPIRVCallLowering::lowerFormalArguments(MachineIRBuilder &MIRBuilder,
         .addUse(GR->getSPIRVTypeID(ArgTypeVRegs[i]));
     if (F.isDeclaration())
       GR->add(&Arg, &MIRBuilder.getMF(), ArgReg);
+    GR->addGlobalObject(&Arg, &MIRBuilder.getMF(), ArgReg);
     i++;
   }
   // Name the function.

llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.cpp

@@ -721,6 +721,7 @@ Register SPIRVGlobalRegistry::buildGlobalVariable(
   }
   Reg = MIB->getOperand(0).getReg();
   DT.add(GVar, &MIRBuilder.getMF(), Reg);
+  addGlobalObject(GVar, &MIRBuilder.getMF(), Reg);
 
   // Set to Reg the same type as ResVReg has.
   auto MRI = MIRBuilder.getMRI();

llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.h

@@ -89,6 +89,10 @@ class SPIRVGlobalRegistry {
   // Intrinsic::spv_assign_ptr_type instructions.
   DenseMap<Value *, CallInst *> AssignPtrTypeInstr;
 
+  // Maps OpVariable and OpFunction-related v-regs to its LLVM IR definition.
+  DenseMap<std::pair<const MachineFunction *, Register>, const Value *>
+      Reg2GO;
+
   // Add a new OpTypeXXX instruction without checking for duplicates.
   SPIRVType *createSPIRVType(const Type *Type, MachineIRBuilder &MIRBuilder,
                              SPIRV::AccessQualifier::AccessQualifier AQ =
@@ -160,6 +164,14 @@ class SPIRVGlobalRegistry {
   void setBound(unsigned V) { Bound = V; }
   unsigned getBound() { return Bound; }
 
+  void addGlobalObject(const Value *V, const MachineFunction *MF, Register R) {
+    Reg2GO[std::make_pair(MF, R)] = V;
+  }
+  const Value *getGlobalObject(const MachineFunction *MF, Register R) {
+    auto It = Reg2GO.find(std::make_pair(MF, R));
+    return It == Reg2GO.end() ? nullptr : It->second;
+  }
+
   // Add a record to the map of function return pointer types.
   void addReturnType(const Function *ArgF, TypedPointerType *DerivedTy) {
     FunResPointerTypes[ArgF] = DerivedTy;

llvm/lib/Target/SPIRV/SPIRVInstrInfo.cpp

@@ -47,6 +47,18 @@ bool SPIRVInstrInfo::isConstantInstr(const MachineInstr &MI) const {
   }
 }
 
+bool SPIRVInstrInfo::isSpecConstantInstr(const MachineInstr &MI) const {
+  switch (MI.getOpcode()) {
+  case SPIRV::OpSpecConstantTrue:
+  case SPIRV::OpSpecConstantFalse:
+  case SPIRV::OpSpecConstant:
+  case SPIRV::OpSpecConstantComposite:
+  case SPIRV::OpSpecConstantOp:
+    return true;
+  default:
+    return false;
+  }
+}
 bool SPIRVInstrInfo::isInlineAsmDefInstr(const MachineInstr &MI) const {
   switch (MI.getOpcode()) {
   case SPIRV::OpAsmTargetINTEL:

llvm/lib/Target/SPIRV/SPIRVInstrInfo.h

@@ -30,6 +30,7 @@ class SPIRVInstrInfo : public SPIRVGenInstrInfo {
   const SPIRVRegisterInfo &getRegisterInfo() const { return RI; }
   bool isHeaderInstr(const MachineInstr &MI) const;
   bool isConstantInstr(const MachineInstr &MI) const;
+  bool isSpecConstantInstr(const MachineInstr &MI) const;
   bool isInlineAsmDefInstr(const MachineInstr &MI) const;
   bool isTypeDeclInstr(const MachineInstr &MI) const;
   bool isDecorationInstr(const MachineInstr &MI) const;

llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp

@@ -1117,6 +1117,7 @@ bool SPIRVInstructionSelector::selectMemOperation(Register ResVReg,
                                             Constant::getNullValue(LLVMArrTy));
     Register VarReg = MRI->createGenericVirtualRegister(LLT::scalar(64));
     GR.add(GV, GR.CurMF, VarReg);
+    GR.addGlobalObject(GV, GR.CurMF, VarReg);
 
     Result &=
         BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(SPIRV::OpVariable))
@@ -3509,18 +3510,25 @@ bool SPIRVInstructionSelector::selectGlobalValue(
         // References to a function via function pointers generate virtual
         // registers without a definition. We will resolve it later, during
         // module analysis stage.
+        Register ResTypeReg = GR.getSPIRVTypeID(ResType);
         MachineRegisterInfo *MRI = MIRBuilder.getMRI();
-        Register FuncVReg = MRI->createGenericVirtualRegister(LLT::scalar(64));
-        MRI->setRegClass(FuncVReg, &SPIRV::iIDRegClass);
-        MachineInstrBuilder MB =
+        Register FuncVReg =
+            MRI->createGenericVirtualRegister(GR.getRegType(ResType));
+        MRI->setRegClass(FuncVReg, &SPIRV::pIDRegClass);
+        MachineInstrBuilder MIB1 =
+            BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpUndef))
+                .addDef(FuncVReg)
+                .addUse(ResTypeReg);
+        MachineInstrBuilder MIB2 =
             BuildMI(BB, I, I.getDebugLoc(),
                     TII.get(SPIRV::OpConstantFunctionPointerINTEL))
                 .addDef(NewReg)
-                .addUse(GR.getSPIRVTypeID(ResType))
+                .addUse(ResTypeReg)
                 .addUse(FuncVReg);
         // mapping the function pointer to the used Function
-        GR.recordFunctionPointer(&MB.getInstr()->getOperand(2), GVFun);
-        return MB.constrainAllUses(TII, TRI, RBI);
+        GR.recordFunctionPointer(&MIB2.getInstr()->getOperand(2), GVFun);
+        return MIB1.constrainAllUses(TII, TRI, RBI) &&
+               MIB2.constrainAllUses(TII, TRI, RBI);
       }
       return BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpConstantNull))
           .addDef(NewReg)