Kernel argument attributes fix for opaque pointers

In case when frontend uses opaque pointers, types used in attributes
like byval are lost and substituted by i8. Try to restore the original
type by analyzing the memory instructions that uses the argument.

Author: mshelego

GenXIntrinsics/lib/GenXIntrinsics/AdaptorsCommon.cpp

@@ -8,6 +8,7 @@ SPDX-License-Identifier: MIT
 
 #include "AdaptorsCommon.h"
 
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
 
@@ -30,6 +31,45 @@ static void legalizeAttribute(Argument &Arg, Type *NewType,
 
 #endif
 
+Type *getPtrElemType(Value *V) {
+#if VC_INTR_LLVM_VERSION_MAJOR < 14
+  return VCINTR::Type::getNonOpaquePtrEltTy(V->getType());
+#else // VC_INTR_LLVM_VERSION_MAJOR < 14
+#if VC_INTR_LLVM_VERSION_MAJOR < 17
+  auto *PtrTy = cast<PointerType>(V->getType());
+  if (!PtrTy->isOpaque())
+    return VCINTR::Type::getNonOpaquePtrEltTy(PtrTy);
+#endif // VC_INTR_LLVM_VERSION_MAJOR < 17
+  SmallPtrSet<Type *, 2> ElemTys;
+  SmallVector<Value *, 4> Stack;
+  Stack.push_back(V);
+  while (!Stack.empty()) {
+    auto* Current = Stack.back();
+    Stack.pop_back();
+    for (auto *U : Current->users()) {
+      if (ElemTys.size() > 1)
+        return nullptr;
+      auto *I = dyn_cast<Instruction>(U);
+      if (!I)
+        continue;
+      if (auto *LI = dyn_cast<LoadInst>(I)) {
+        if (Current == LI->getPointerOperand())
+          ElemTys.insert(LI->getType());
+      } else if (auto *SI = dyn_cast<StoreInst>(I)) {
+        if (Current == SI->getPointerOperand())
+          ElemTys.insert(SI->getValueOperand()->getType());
+      } else if (auto *GEPI = dyn_cast<GetElementPtrInst>(I)) {
+        if (Current == GEPI->getPointerOperand())
+          ElemTys.insert(GEPI->getSourceElementType());
+      } else if (isa<BitCastInst>(I) || isa<AddrSpaceCastInst>(I)) {
+        Stack.push_back(I);
+      }
+    }
+  }
+  return ElemTys.empty() ? nullptr : *ElemTys.begin();
+#endif // VC_INTR_LLVM_VERSION_MAJOR < 14
+}
+
 void legalizeParamAttributes(Function *F) {
   assert(F && "Valid function ptr must be passed");
 
@@ -39,15 +79,12 @@ void legalizeParamAttributes(Function *F) {
     if (!PTy)
       continue;
 
+    auto *ElemType = getPtrElemType(&Arg);
 #if VC_INTR_LLVM_VERSION_MAJOR >= 13
-#if VC_INTR_LLVM_VERSION_MAJOR < 17
-    if (PTy->isOpaque())
-#endif // VC_INTR_LLVM_VERSION_MAJOR < 18
+    if (!ElemType)
       continue;
 #endif // VC_INTR_LLVM_VERSION_MAJOR >= 13
 
-    auto *ElemType = VCINTR::Type::getNonOpaquePtrEltTy(PTy);
-
     legalizeAttribute(Arg, ElemType, Attribute::ByVal);
 
 #if VC_INTR_LLVM_VERSION_MAJOR >= 11

GenXIntrinsics/lib/GenXIntrinsics/GenXSPIRVReaderAdaptor.cpp

@@ -481,8 +481,7 @@ transformKernelSignature(Function &F, const std::vector<SPIRVArgDesc> &Descs) {
                        return PointerType::get(Type::getInt8Ty(Ctx), AddrSpace);
                      }
 #endif
-                     if (!VCINTR::Type::isOpaquePointerTy(ArgTy) &&
-                         Arg.hasByValAttr())
+                     if (Arg.hasByValAttr())
                        return OrigTy;
 
                      return ArgTy;
@@ -523,8 +522,6 @@ transformKernelSignature(Function &F, const std::vector<SPIRVArgDesc> &Descs) {
     NewF->addParamAttr(i, Attr);
   }
 
-  legalizeParamAttributes(NewF);
-
   return NewF;
 }
 
@@ -606,6 +603,8 @@ static void rewriteKernelArguments(Function &F) {
     }
   }
 
+  legalizeParamAttributes(NewF);
+
   F.mutateType(NewF->getType());
   F.replaceAllUsesWith(NewF);
   F.eraseFromParent();

GenXIntrinsics/test/Adaptors/opaque_ptrs/args_attributes_transform_reader.ll

@@ -21,4 +21,15 @@ define spir_kernel void @test(ptr addrspace(1) byval(%foo) %arg) #0 {
   ret void
 }
 
+; CHECK: define dllexport spir_kernel void @test_restore(
+; CHECK-SAME: ptr byval(%foo)
+; CHECK-SAME: [[ARG:%[^)]+]])
+define spir_kernel void @test_restore(ptr addrspace(1) byval(i8) %arg) #0 {
+  %conv = call ptr @llvm.genx.address.convert.p0foo.p1(ptr addrspace(1) %arg)
+  %gep = getelementptr %foo, ptr %conv, i64 0, i32 0
+  ret void
+}
+
+declare ptr @llvm.genx.address.convert.p0foo.p1(ptr addrspace(1)) #0
+
 attributes #0 = { "VCFunction" }