Introduce CodeSectionINTEL storage class

include/LLVMSPIRVOpts.h

@@ -233,6 +233,14 @@ class TranslatorOpts {
     PreserveOCLKernelArgTypeMetadataThroughString = Value;
   }
 
+  bool shouldEmitFunctionPtrAddrSpace() const noexcept {
+    return EmitFunctionPtrAddrSpace;
+  }
+
+  void setEmitFunctionPtrAddrSpace(bool Value) noexcept {
+    EmitFunctionPtrAddrSpace = Value;
+  }
+
   void setBuiltinFormat(BuiltinFormat Value) noexcept {
     SPIRVBuiltinFormat = Value;
   }
@@ -281,6 +289,10 @@ class TranslatorOpts {
   // kernel_arg_type_qual metadata through OpString
   bool PreserveOCLKernelArgTypeMetadataThroughString = false;
 
+  // Controls if CodeSectionINTEL can be emitted and consumed with a dedicated
+  // address space
+  bool EmitFunctionPtrAddrSpace = false;
+
   bool PreserveAuxData = false;
 
   BuiltinFormat SPIRVBuiltinFormat = BuiltinFormat::Function;

lib/SPIRV/SPIRVInternal.h

@@ -189,6 +189,7 @@ enum SPIRAddressSpace {
   SPIRAS_GlobalHost,
   SPIRAS_Input,
   SPIRAS_Output,
+  SPIRAS_CodeSectionINTEL,
   SPIRAS_Count,
 };
 
@@ -199,6 +200,8 @@ template <> inline void SPIRVMap<SPIRAddressSpace, std::string>::init() {
   add(SPIRAS_Local, "Local");
   add(SPIRAS_Generic, "Generic");
   add(SPIRAS_Input, "Input");
+  add(SPIRAS_CodeSectionINTEL, "CodeSectionINTEL");
+
   add(SPIRAS_GlobalDevice, "GlobalDevice");
   add(SPIRAS_GlobalHost, "GlobalHost");
 }
@@ -215,6 +218,7 @@ inline void SPIRVMap<SPIRAddressSpace, SPIRVStorageClassKind>::init() {
   add(SPIRAS_Input, StorageClassInput);
   add(SPIRAS_GlobalDevice, StorageClassDeviceOnlyINTEL);
   add(SPIRAS_GlobalHost, StorageClassHostOnlyINTEL);
+  add(SPIRAS_CodeSectionINTEL, StorageClassCodeSectionINTEL);
 }
 typedef SPIRVMap<SPIRAddressSpace, SPIRVStorageClassKind> SPIRSPIRVAddrSpaceMap;
 

lib/SPIRV/SPIRVReader.cpp

@@ -348,16 +348,21 @@ Type *SPIRVToLLVM::transType(SPIRVType *T, bool UseTPT) {
   case internal::OpTypeTokenINTEL:
     return mapType(T, Type::getTokenTy(*Context));
   case OpTypePointer: {
-    const unsigned AS =
-        SPIRSPIRVAddrSpaceMap::rmap(T->getPointerStorageClass());
+    unsigned AS = SPIRSPIRVAddrSpaceMap::rmap(T->getPointerStorageClass());
+    if (AS == SPIRAS_CodeSectionINTEL && !BM->shouldEmitFunctionPtrAddrSpace())
+      AS = SPIRAS_Private;
+    if (BM->shouldEmitFunctionPtrAddrSpace() &&
+        T->getPointerElementType()->getOpCode() == OpTypeFunction)
+      AS = SPIRAS_CodeSectionINTEL;
     Type *ElementTy = transType(T->getPointerElementType(), UseTPT);
     if (UseTPT)
       return TypedPointerType::get(ElementTy, AS);
     return mapType(T, PointerType::get(ElementTy, AS));
   }
   case OpTypeUntypedPointerKHR: {
-    const unsigned AS =
-        SPIRSPIRVAddrSpaceMap::rmap(T->getPointerStorageClass());
+    unsigned AS = SPIRSPIRVAddrSpaceMap::rmap(T->getPointerStorageClass());
+    if (AS == SPIRAS_CodeSectionINTEL && !BM->shouldEmitFunctionPtrAddrSpace())
+      AS = SPIRAS_Private;
     return mapType(T, PointerType::get(*Context, AS));
   }
   case OpTypeVector:
@@ -1469,6 +1474,17 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
     case OpTypeMatrix:
     case OpTypeArray: {
       auto *AT = cast<ArrayType>(transType(BCC->getType()));
+      for (size_t I = 0; I != AT->getNumElements(); ++I) {
+        auto *ElemTy = AT->getElementType();
+        if (auto *ElemPtrTy = dyn_cast<PointerType>(ElemTy)) {
+          assert(isa<PointerType>(CV[I]->getType()) &&
+                 "Constant type doesn't match constexpr array element type");
+          if (ElemPtrTy->getAddressSpace() !=
+              cast<PointerType>(CV[I]->getType())->getAddressSpace())
+            CV[I] = ConstantExpr::getAddrSpaceCast(CV[I], AT->getElementType());
+        }
+      }
+
       return mapValue(BV, ConstantArray::get(AT, CV));
     }
     case OpTypeStruct: {
@@ -1485,7 +1501,12 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
               !BCCTy->getElementType(I)->isPointerTy())
             continue;
 
-          CV[I] = ConstantExpr::getBitCast(CV[I], BCCTy->getElementType(I));
+          if (cast<PointerType>(CV[I]->getType())->getAddressSpace() !=
+              cast<PointerType>(BCCTy->getElementType(I))->getAddressSpace())
+            CV[I] =
+                ConstantExpr::getAddrSpaceCast(CV[I], BCCTy->getElementType(I));
+          else
+            CV[I] = ConstantExpr::getBitCast(CV[I], BCCTy->getElementType(I));
         }
       }
 
@@ -1521,7 +1542,10 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
         static_cast<SPIRVConstantFunctionPointerINTEL *>(BV);
     SPIRVFunction *F = BC->getFunction();
     BV->setName(F->getName());
-    return mapValue(BV, transFunction(F));
+    const unsigned AS = BM->shouldEmitFunctionPtrAddrSpace()
+                            ? SPIRAS_CodeSectionINTEL
+                            : SPIRAS_Private;
+    return mapValue(BV, transFunction(F, AS));
   }
 
   case OpUndef:
@@ -3040,7 +3064,7 @@ void SPIRVToLLVM::transFunctionAttrs(SPIRVFunction *BF, Function *F) {
   });
 }
 
-Function *SPIRVToLLVM::transFunction(SPIRVFunction *BF) {
+Function *SPIRVToLLVM::transFunction(SPIRVFunction *BF, unsigned AS) {
   auto Loc = FuncMap.find(BF);
   if (Loc != FuncMap.end())
     return Loc->second;
@@ -3088,7 +3112,7 @@ Function *SPIRVToLLVM::transFunction(SPIRVFunction *BF) {
   }
   Function *F = M->getFunction(FuncName);
   if (!F)
-    F = Function::Create(FT, Linkage, FuncName, M);
+    F = Function::Create(FT, Linkage, AS, FuncName, M);
   F = cast<Function>(mapValue(BF, F));
   mapFunction(BF, F);
 
@@ -3495,6 +3519,17 @@ bool SPIRVToLLVM::translate() {
     DbgTran->transDebugInst(EI);
   }
 
+  for (auto *FP : BM->getFunctionPointers()) {
+    SPIRVConstantFunctionPointerINTEL *BC =
+        static_cast<SPIRVConstantFunctionPointerINTEL *>(FP);
+    SPIRVFunction *F = BC->getFunction();
+    FP->setName(F->getName());
+    const unsigned AS = BM->shouldEmitFunctionPtrAddrSpace()
+                            ? SPIRAS_CodeSectionINTEL
+                            : SPIRAS_Private;
+    mapValue(FP, transFunction(F, AS));
+  }
+
   for (unsigned I = 0, E = BM->getNumFunctions(); I != E; ++I) {
     transFunction(BM->getFunction(I));
     transUserSemantic(BM->getFunction(I));

lib/SPIRV/SPIRVReader.h

@@ -103,7 +103,7 @@ class SPIRVToLLVM : private BuiltinCallHelper {
   void transAuxDataInst(SPIRVExtInst *BC);
   std::vector<Value *> transValue(const std::vector<SPIRVValue *> &,
                                   Function *F, BasicBlock *);
-  Function *transFunction(SPIRVFunction *F);
+  Function *transFunction(SPIRVFunction *F, unsigned AS = SPIRAS_Private);
   void transFunctionAttrs(SPIRVFunction *BF, Function *F);
   Value *transBlockInvoke(SPIRVValue *Invoke, BasicBlock *BB);
   Instruction *transWGSizeQueryBI(SPIRVInstruction *BI, BasicBlock *BB);

lib/SPIRV/SPIRVWriter.cpp

@@ -655,6 +655,11 @@ SPIRVType *LLVMToSPIRVBase::transPointerType(Type *ET, unsigned AddrSpc) {
       ((AddrSpc == SPIRAS_GlobalDevice) || (AddrSpc == SPIRAS_GlobalHost))) {
     return transPointerType(ET, SPIRAS_Global);
   }
+  // Lower function pointer address space to private if
+  // spirv-emit-function-ptr-addr-space is not passed
+  if (AddrSpc == SPIRAS_CodeSectionINTEL &&
+      !BM->shouldEmitFunctionPtrAddrSpace())
+    return transPointerType(ET, SPIRAS_Private);
   if (ST && !ST->isSized()) {
     Op OpCode;
     StringRef STName = ST->getName();
@@ -750,6 +755,9 @@ SPIRVType *LLVMToSPIRVBase::transPointerType(SPIRVType *ET, unsigned AddrSpc) {
     return Loc->second;
 
   SPIRVType *TranslatedTy = nullptr;
+  if (AddrSpc == SPIRAS_CodeSectionINTEL &&
+      !BM->shouldEmitFunctionPtrAddrSpace())
+    return transPointerType(ET, SPIRAS_Private);
   if (BM->isAllowedToUseExtension(ExtensionID::SPV_KHR_untyped_pointers) &&
       !(ET->isTypeArray() || ET->isTypeVector() || ET->isTypeImage() ||
         ET->isTypeSampler() || ET->isTypePipe())) {

lib/SPIRV/libSPIRV/SPIRVInstruction.cpp

@@ -282,6 +282,11 @@ SPIRVInstruction *createInstFromSpecConstantOp(SPIRVSpecConstantOp *Inst) {
   auto OC = static_cast<Op>(Ops[0]);
   assert(isSpecConstantOpAllowedOp(OC) &&
          "Op code not allowed for OpSpecConstantOp");
+  auto *Const = Inst->getOperand(1);
+  // LLVM would eliminate a bitcast from a function pointer in a constexpr
+  // context. Cut this short here to avoid necessity to align address spaces
+  if (OC == OpBitcast && Const->getOpCode() == OpConstantFunctionPointerINTEL)
+    return static_cast<SPIRVInstruction *>(Const);
   Ops.erase(Ops.begin(), Ops.begin() + 1);
   auto *BM = Inst->getModule();
   auto *RetInst = SPIRVInstTemplateBase::create(

lib/SPIRV/libSPIRV/SPIRVModule.cpp

@@ -142,6 +142,13 @@ class SPIRVModuleImpl : public SPIRVModule {
   SPIRVConstant *getLiteralAsConstant(unsigned Literal) override;
   unsigned getNumFunctions() const override { return FuncVec.size(); }
   unsigned getNumVariables() const override { return VariableVec.size(); }
+  std::vector<SPIRVValue *> getFunctionPointers() const override {
+    std::vector<SPIRVValue *> Res;
+    for (auto *C : ConstVec)
+      if (C->getOpCode() == OpConstantFunctionPointerINTEL)
+        Res.emplace_back(C);
+    return Res;
+  }
   SourceLanguage getSourceLanguage(SPIRVWord *Ver = nullptr) const override {
     if (Ver)
       *Ver = SrcLangVer;

lib/SPIRV/libSPIRV/SPIRVModule.h

@@ -142,6 +142,7 @@ class SPIRVModule {
   virtual SPIRVMemoryModelKind getMemoryModel() const = 0;
   virtual unsigned getNumFunctions() const = 0;
   virtual unsigned getNumVariables() const = 0;
+  virtual std::vector<SPIRVValue *> getFunctionPointers() const = 0;
   virtual SourceLanguage getSourceLanguage(SPIRVWord *) const = 0;
   virtual std::set<std::string> &getSourceExtension() = 0;
   virtual SPIRVValue *getValue(SPIRVId TheId) const = 0;
@@ -553,6 +554,10 @@ class SPIRVModule {
         .shouldPreserveOCLKernelArgTypeMetadataThroughString();
   }
 
+  bool shouldEmitFunctionPtrAddrSpace() const noexcept {
+    return TranslationOpts.shouldEmitFunctionPtrAddrSpace();
+  }
+
   bool preserveAuxData() const noexcept {
     return TranslationOpts.preserveAuxData();
   }

test/extensions/INTEL/SPV_INTEL_function_pointers/CodeSectionINTEL/alias.ll

@@ -0,0 +1,49 @@
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv -spirv-ext=+SPV_INTEL_function_pointers -spirv-text %t.bc -o - | FileCheck %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv -spirv-ext=+SPV_INTEL_function_pointers %t.bc -o %t.spv
+; RUN: llvm-spirv -r -spirv-emit-function-ptr-addr-space %t.spv -o - | llvm-dis -o - | FileCheck %s --check-prefix=CHECK-LLVM
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-unknown"
+
+; Check that aliases are dereferenced and translated to their aliasee values
+; when used since they can't be translated directly.
+
+; CHECK-SPIRV-DAG: Name [[#FOO:]] "foo"
+; CHECK-SPIRV-DAG: Name [[#BAR:]] "bar"
+; CHECK-SPIRV-DAG: Name [[#Y:]] "y"
+; CHECK-SPIRV-DAG: Name [[#FOOPTR:]] "foo.alias"
+; CHECK-SPIRV-DAG: Decorate [[#FOO]] LinkageAttributes "foo" Export
+; CHECK-SPIRV-DAG: Decorate [[#BAR]] LinkageAttributes "bar" Export
+; CHECK-SPIRV-DAG: TypeInt [[#I32:]] 32 0
+; CHECK-SPIRV-DAG: TypeInt [[#I64:]] 64 0
+; CHECK-SPIRV-DAG: TypeFunction [[#FOO_TYPE:]] [[#I32]] [[#I32]]
+; CHECK-SPIRV-DAG: TypeVoid [[#VOID:]]
+; CHECK-SPIRV-DAG: TypePointer [[#I64PTR:]] 7 [[#I64]]
+; CHECK-SPIRV-DAG: TypeFunction [[#BAR_TYPE:]] [[#VOID]] [[#I64PTR]]
+; CHECK-SPIRV-DAG: TypePointer [[#FOOPTR_TYPE:]] 7 [[#FOO_TYPE]]
+; CHECK-SPIRV-DAG: ConstantFunctionPointerINTEL [[#FOOPTR_TYPE]] [[#FOOPTR]] [[#FOO]]
+
+; CHECK-SPIRV: Function [[#I32]] [[#FOO]] 0 [[#FOO_TYPE]]
+
+; CHECK-SPIRV: Function [[#VOID]] [[#BAR]] 0 [[#BAR_TYPE]]
+; CHECK-SPIRV: FunctionParameter [[#I64PTR]] [[#Y]]
+; CHECK-SPIRV: ConvertPtrToU [[#I64]] [[#PTRTOINT:]] [[#FOOPTR]]
+; CHECK-SPIRV: Store [[#Y]] [[#PTRTOINT]] 2 8
+
+; CHECK-LLVM: define spir_func i32 @foo(i32 %x) addrspace(9)
+
+; CHECK-LLVM: define spir_kernel void @bar(ptr %y)
+; CHECK-LLVM: [[PTRTOINT:%.*]] = ptrtoint ptr addrspace(9) @foo to i64
+; CHECK-LLVM: store i64 [[PTRTOINT]], ptr %y, align 8
+
+define spir_func i32 @foo(i32 %x) {
+  ret i32 %x
+}
+
+@foo.alias = internal alias i32 (i32), ptr @foo
+
+define spir_kernel void @bar(ptr %y) {
+  store i64 ptrtoint (ptr @foo.alias to i64), ptr %y
+  ret void
+}

test/extensions/INTEL/SPV_INTEL_function_pointers/CodeSectionINTEL/bitcast.ll

@@ -0,0 +1,53 @@
+; OpenCL C source:
+; char foo(char a) {
+;     return a;
+; }
+; void bar() {
+;    int (*fun_ptr)(int) = &foo;
+;    fun_ptr(0);
+; }
+
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv %t.bc -spirv-ext=+SPV_INTEL_function_pointers -o %t.spv
+; RUN: llvm-spirv %t.spv -to-text -o %t.spt
+; RUN: FileCheck < %t.spt %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv -r -spirv-emit-function-ptr-addr-space %t.spv -o %t.r.bc
+; RUN: llvm-dis %t.r.bc -o %t.r.ll
+; RUN: FileCheck < %t.r.ll %s --check-prefix=CHECK-LLVM
+
+; CHECK-SPIRV-DAG: TypeInt [[#I8:]] 8
+; CHECK-SPIRV-DAG: TypeInt [[#I32:]] 32
+; CHECK-SPIRV-DAG: TypeFunction [[#FOO_TY:]] [[#I8]] [[#I8]]
+; CHECK-SPIRV-DAG: TypeFunction [[#DEST_TY:]] [[#I32]] [[#I32]]
+; CHECK-SPIRV-DAG: TypePointer [[#DEST_TY_PTR:]] [[#]] [[#DEST_TY]]
+; CHECK-SPIRV-DAG: TypePointer [[#FOO_TY_PTR:]] [[#]] [[#FOO_TY]]
+; CHECK-SPIRV: ConstantFunctionPointerINTEL [[#FOO_TY_PTR]] [[#FOO_PTR:]] [[#FOO:]]
+; CHECK-SPIRV: Function [[#]] [[#FOO]] [[#]] [[#FOO_TY]]
+
+; CHECK-SPIRV: Bitcast [[#DEST_TY_PTR]] [[#]] [[#FOO_PTR]]
+
+; CHECK-LLVM: bitcast ptr addrspace(9) @foo to ptr addrspace(9)
+
+; ModuleID = './example.c'
+source_filename = "./example.c"
+target datalayout = "e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir"
+
+; Function Attrs: noinline nounwind optnone
+define dso_local spir_func signext i8 @foo(i8 signext %0) #0 {
+  ret i8 %0
+}
+
+; Function Attrs: noinline nounwind optnone
+define dso_local spir_func void @bar() #0 {
+  %1 = call i32 @foo(i32 0)
+  ret void
+}
+
+attributes #0 = { noinline nounwind optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.module.flags = !{!0}
+!llvm.ident = !{!1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{!"clang version 11.0.0 (https://github.com/llvm/llvm-project.git 0e1accd0f726eef2c47be9f37dd0a06cb50d207e)"}