Show warning on @llvm.global.annotations usage

In case @llvm.global.annotations is used, parse its contents and show
a warning about ignored annotations. Also update the function pointer in
the structure when the function is rewritten

Author: mshelego

IGC/VectorCompiler/lib/GenXCodeGen/GenXCisaBuilder.cpp

@@ -6296,6 +6296,27 @@ void GenXKernelBuilder::buildStackCallLight(CallInst *CI,
   }
 }
 
+static void dumpGlobalAnnotations(Module &M) {
+  auto *GV = M.getGlobalVariable("llvm.global.annotations");
+  if (!GV)
+    return;
+  auto *Array = dyn_cast<ConstantArray>(GV->getOperand(0));
+  for (const auto &Op : Array->operands()) {
+    auto *Struct = dyn_cast<ConstantStruct>(Op.get());
+    auto *Func = dyn_cast<Function>(Struct->getOperand(0)->getOperand(0));
+    if (!Func)
+      continue;
+    auto FuncName = Func->getName();
+    assert(!FuncName.empty() && "Annotated function must have a name");
+    auto *GlobalStr =
+        dyn_cast<GlobalVariable>(Struct->getOperand(1)->getOperand(0));
+    auto *Str = dyn_cast<ConstantDataArray>(GlobalStr->getInitializer());
+    auto FuncAnnotation = Str->getAsString();
+    errs() << "Warning: Annotation \"" << FuncAnnotation << "\" for function "
+           << FuncName << " is ignored\n";
+  }
+}
+
 namespace {
 
 class GenXFinalizer : public ModulePass {
@@ -6338,6 +6359,8 @@ class GenXFinalizer : public ModulePass {
 
     Out << ss.str();
 
+    dumpGlobalAnnotations(M);
+
     // Collect some useful statistics
     for (auto *FG: FGA) {
       VISAKernel *Kernel = CisaBuilder->GetVISAKernel(FG->getName().str());

IGC/VectorCompiler/lib/GenXOpts/CMTrans/CMImpParam.cpp

@@ -1213,6 +1213,9 @@ CMImpParam::processKernelParameters(Function *F,
   KM.updateArgKindsMD(std::move(ArgKinds));
   KM.updateLinearizationMD(std::move(LinearizedArgs));
 
+  F->mutateType(NF->getType());
+  F->replaceAllUsesWith(NF);
+
   // Now that the old function is dead, delete it. If there is a dangling
   // reference to the CallGraphNode, just leave the dead function around
   NF_CGN->stealCalledFunctionsFrom(CG[F]);