Add AddPrimitiveTypesPass to Decompiler

This pass is in charge of creating all the primitive types for any
of the typical sizes used for numbers.

lib/Decompiler/AddPrimitiveTypesPass.cpp

@@ -0,0 +1,41 @@
+//
+// Copyright (c) rev.ng Srls. See LICENSE.md for details.
+//
+
+#include "revng/Model/LoadModelPass.h"
+#include "revng/Model/Type.h"
+
+#include "revng-c/Decompiler/AddPrimitiveTypesPass.h"
+
+char AddPrimitiveTypesPass::ID = 0;
+
+using Register = llvm::RegisterPass<AddPrimitiveTypesPass>;
+static ::Register
+  X("add-primitives", "Pass to add primitive types to Model", false, false);
+
+void AddPrimitiveTypesPass::getAnalysisUsage(llvm::AnalysisUsage &AU) const {
+  AU.addRequired<LoadModelWrapperPass>();
+  AU.setPreservesAll();
+}
+
+using namespace model::PrimitiveTypeKind;
+
+bool AddPrimitiveTypesPass::runOnModule(llvm::Module &M) {
+  auto &ModelWrapper = getAnalysis<LoadModelWrapperPass>().get();
+  auto &WritableModel = ModelWrapper.getWriteableModel();
+
+  // For each of these types, we want to have in the model a corresponding
+  // PrimitiveType for each possible dimension
+  static constexpr const Values PrimitiveTypes[] = {
+    Generic, PointerOrNumber, Number, Unsigned, Signed
+  };
+  // TODO: Add 128-bit numbers if needed
+  static constexpr const uint8_t Sizes[] = { 1, 2, 4, 8 };
+
+  // getPrimitiveType() creates the type if it does not exist
+  for (auto &Type : PrimitiveTypes)
+    for (auto &Size : Sizes)
+      WritableModel->getPrimitiveType(Type, Size);
+
+  return true;
+}