[SPIR-V] Fix SPIR-V extension SPV_INTEL_function_pointers: introduce CodeSectionINTEL (#117250)

This PR fixes generation of OpConstantFunctionPointerINTEL instruction
for the SPIR-V extension SPV_INTEL_function_pointers. Result type of
OpConstantFunctionPointerINTEL must be OpTypePointer with Storage Class
operand equal to CodeSectionINTEL.

See also #116636

CC: @MrSidims

Author: VyacheslavLevytskyy

llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp

@@ -3316,9 +3316,6 @@ bool SPIRVInstructionSelector::selectGlobalValue(
     PointerBaseType = GR.getOrCreateSPIRVType(
         GVType, MIRBuilder, SPIRV::AccessQualifier::ReadWrite, false);
   }
-  SPIRVType *ResType = GR.getOrCreateSPIRVPointerType(
-      PointerBaseType, I, TII,
-      addressSpaceToStorageClass(GV->getAddressSpace(), STI));
 
   std::string GlobalIdent;
   if (!GV->hasName()) {
@@ -3351,6 +3348,10 @@ bool SPIRVInstructionSelector::selectGlobalValue(
           STI.canUseExtension(SPIRV::Extension::SPV_INTEL_function_pointers)
               ? dyn_cast<Function>(GV)
               : nullptr;
+      SPIRVType *ResType = GR.getOrCreateSPIRVPointerType(
+          PointerBaseType, I, TII,
+          GVFun ? SPIRV::StorageClass::CodeSectionINTEL
+                : addressSpaceToStorageClass(GV->getAddressSpace(), STI));
       if (GVFun) {
         // References to a function via function pointers generate virtual
         // registers without a definition. We will resolve it later, during
@@ -3402,6 +3403,9 @@ bool SPIRVInstructionSelector::selectGlobalValue(
                  ? SPIRV::LinkageType::LinkOnceODR
                  : SPIRV::LinkageType::Export);
 
+  SPIRVType *ResType = GR.getOrCreateSPIRVPointerType(
+      PointerBaseType, I, TII,
+      addressSpaceToStorageClass(GV->getAddressSpace(), STI));
   Register Reg = GR.buildGlobalVariable(ResVReg, ResType, GlobalIdent, GV,
                                         Storage, Init, GlobalVar->isConstant(),
                                         HasLnkTy, LnkType, MIRBuilder, true);

llvm/lib/Target/SPIRV/SPIRVUtils.cpp

@@ -205,6 +205,8 @@ addressSpaceToStorageClass(unsigned AddrSpace, const SPIRVSubtarget &STI) {
                : SPIRV::StorageClass::CrossWorkgroup;
   case 7:
     return SPIRV::StorageClass::Input;
+  case 9:
+    return SPIRV::StorageClass::CodeSectionINTEL;
   default:
     report_fatal_error("Unknown address space");
   }

llvm/lib/Target/SPIRV/SPIRVUtils.h

@@ -166,6 +166,8 @@ storageClassToAddressSpace(SPIRV::StorageClass::StorageClass SC) {
     return 6;
   case SPIRV::StorageClass::Input:
     return 7;
+  case SPIRV::StorageClass::CodeSectionINTEL:
+    return 9;
   default:
     report_fatal_error("Unable to get address space id");
   }

llvm/test/CodeGen/SPIRV/extensions/SPV_INTEL_function_pointers/fp_const.ll

@@ -10,8 +10,9 @@
 ; CHECK-DAG: %[[TyInt64:.*]] = OpTypeInt 64 0
 ; CHECK-DAG: %[[TyFun:.*]] = OpTypeFunction %[[TyInt64]] %[[TyInt64]]
 ; CHECK-DAG: %[[TyInt8:.*]] = OpTypeInt 8 0
+; CHECK-DAG: %[[TyPtrFunCodeSection:.*]] = OpTypePointer CodeSectionINTEL %[[TyFun]]
+; CHECK-DAG: %[[ConstFunFp:.*]] = OpConstantFunctionPointerINTEL %[[TyPtrFunCodeSection]] %[[DefFunFp:.*]]
 ; CHECK-DAG: %[[TyPtrFun:.*]] = OpTypePointer Function %[[TyFun]]
-; CHECK-DAG: %[[ConstFunFp:.*]] = OpConstantFunctionPointerINTEL %[[TyPtrFun]] %[[DefFunFp:.*]]
 ; CHECK-DAG: %[[TyPtrPtrFun:.*]] = OpTypePointer Function %[[TyPtrFun]]
 ; CHECK-DAG: %[[TyPtrInt8:.*]] = OpTypePointer Function %[[TyInt8]]
 ; CHECK-DAG: %[[TyPtrPtrInt8:.*]] = OpTypePointer Function %[[TyPtrInt8]]