[LLVM16] Removal of Reapply_hasSetOpaquePointersValue.patch

In order to reduce the amount of patches this PR moves
check whether pointers mode was already set from LLVM to IGC

More details in comments

Author: bokrzesi

IGC/Compiler/CodeGenContext.cpp

@@ -312,11 +312,22 @@ LLVMContextWrapper::LLVMContextWrapper(bool createResourceDimTypes) : m_UserAddr
   // perform automatic conversion of builtin types which should be represented using TargetExtTy.
   // TODO: For transition purposes, consider introducing an IGC internal option to tweak typed/opaque pointers
   // with a precedence over the environment flag.
-  if (IGC::canOverwriteLLVMCtxPtrMode(basePtr)) {
-    bool enableOpaquePointers = AreOpaquePointersEnabled();
 
+  // TODO: Remove/Re-evaluate once fully moved to the LLVM 16 opaque ptrs.
+  // This WA_OpaquePointersCL flag is related to the same flag in LLVM itself
+  // We're using it here to have consistent behaviour.
+  // https://github.com/llvm/llvm-project/blob/release/16.x/llvm/lib/IR/LLVMContextImpl.cpp#L50
+  auto WA_OpaquePointersCL = cl::getRegisteredOptions()["opaque-pointers"];
+  if (WA_OpaquePointersCL && WA_OpaquePointersCL->getNumOccurrences() > 0) {
+    IGC_IsPointerModeAlreadySet = true;
+  }
+  
+  if (IGC::canOverwriteLLVMCtxPtrMode(basePtr, IGC_IsPointerModeAlreadySet)) {
+    bool enableOpaquePointers = AreOpaquePointersEnabled();
     IGCLLVM::setOpaquePointers(basePtr, enableOpaquePointers);
+    IGC_IsPointerModeAlreadySet = true;
   }
+  // TODO: end
 }
 
 void LLVMContextWrapper::AddRef() { refCount++; }

IGC/Compiler/CodeGenPublic.h

@@ -768,6 +768,11 @@ class LLVMContextWrapper : public llvm::LLVMContext {
   llvm::SmallVector<llvm::StructType *, 16> m_allLayoutStructTypes;
   void AddRef();
   void Release();
+
+  // TODO: Remove after switch to LLVM 16 opque pointers.
+  // In order to get rid of `Reapply_hasSetOpaquePointersValue.patch` patch, we're implementing
+  // check if pointer type was set in IGC.
+  bool IGC_IsPointerModeAlreadySet = false;
 };
 
 struct RoutingIndex {

IGC/WrapperLLVM/include/llvmWrapper/IR/LLVMContext.h

@@ -1,6 +1,6 @@
 /*========================== begin_copyright_notice ============================
 
-Copyright (C) 2024 Intel Corporation
+Copyright (C) 2025 Intel Corporation
 
 SPDX-License-Identifier: MIT
 
@@ -27,7 +27,7 @@ inline void setOpaquePointers(llvm::LLVMContext *Ctx, const bool Enable) {
 } // end namespace IGCLLVM
 
 namespace IGC {
-inline bool canOverwriteLLVMCtxPtrMode(llvm::LLVMContext *Ctx) {
+inline bool canOverwriteLLVMCtxPtrMode(llvm::LLVMContext *Ctx, bool IGC_IsPointerModeAlreadySet) {
   IGC_ASSERT_MESSAGE(Ctx, "Null LLVMContext pointer!");
 #if LLVM_VERSION_MAJOR == 14
   // With LLVM 14, we invoke a proper check for the -opaque-pointers CL
@@ -36,11 +36,16 @@ inline bool canOverwriteLLVMCtxPtrMode(llvm::LLVMContext *Ctx) {
   // override this when opaque pointers are force-enabled in experimental
   // mode.
   return Ctx->supportsTypedPointers();
-#elif LLVM_VERSION_MAJOR >= 15
+#elif LLVM_VERSION_MAJOR == 15
   // With LLVM 15-16, we should not trigger CL option evaluation, as the
   // OPs mode will then get set as a permanent default. The only
   // alternative is to use an API below, non-native for LLVM 16.
   return !Ctx->hasSetOpaquePointersValue();
+#elif LLVM_VERSION_MAJOR >= 16
+  // LLVM 16: we start removing switching between typed/opaque ptrs mode
+  // In order to prepare for full move to the opaque pointers.
+  // The first step is to get rid of .patches related to opaque pointers mode.
+  return !IGC_IsPointerModeAlreadySet;
 #endif // LLVM_VERSION_MAJOR
 }
 } // end namespace IGC