revng-revng/lib/TypeNames/ModelTypeNames.cpp

//
// Copyright (c) rev.ng Labs Srl. See LICENSE.md for details.
//

#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Type.h"

#include "revng/ABI/FunctionType/Layout.h"
#include "revng/Model/Binary.h"
#include "revng/Model/CABIFunctionType.h"
#include "revng/Model/Identifier.h"
#include "revng/Model/QualifiedType.h"
#include "revng/Model/RawFunctionType.h"
#include "revng/PTML/Constants.h"
#include "revng/PTML/ModelHelpers.h"
#include "revng/PTML/Tag.h"
#include "revng/Pipeline/Location.h"
#include "revng/Support/Assert.h"
#include "revng/Support/FunctionTags.h"

#include "revng-c/Pipes/Ranks.h"
#include "revng-c/Support/FunctionTags.h"
#include "revng-c/Support/ModelHelpers.h"
#include "revng-c/Support/PTMLC.h"
#include "revng-c/TypeNames/ModelTypeNames.h"

using llvm::dyn_cast;
using llvm::isa;
using llvm::StringRef;
using llvm::Twine;
using tokenDefinition::types::TypeString;

using modelEditPath::getCustomNamePath;
using pipeline::serializedLocation;
using ptml::str;
using ptml::Tag;
namespace tags = ptml::tags;
namespace attributes = ptml::attributes;
namespace tokens = ptml::c::tokens;
namespace ranks = revng::ranks;

using namespace ArtificialTypes;

template<typename FT>
// clang-format off
concept ModelFunction = std::same_as<FT, model::Function>
                        or std::same_as<FT, model::DynamicFunction>;
// clang-format on

static std::string serializeVariableLocation(llvm::StringRef VariableName,
                                             const model::DynamicFunction &F) {
  return pipeline::serializedLocation(ranks::DynamicFunctionArgument,
                                      F.key(),
                                      VariableName.str());
}

static std::string serializeVariableLocation(llvm::StringRef VariableName,
                                             const model::Function &F) {
  return pipeline::serializedLocation(ranks::LocalVariable,
                                      F.key(),
                                      VariableName.str());
}

template<bool IsDefinition, ModelFunction FunctionType>
static std::string
getArgumentLocation(llvm::StringRef ArgumentName, const FunctionType &F) {
  return Tag(tags::Span, ArgumentName)
    .addAttribute(attributes::Token, tokens::FunctionParameter)
    .addAttribute(ptml::locationAttribute(IsDefinition),
                  serializeVariableLocation(ArgumentName, F))
    .serialize();
}

static std::string
getArgumentLocationDefinition(llvm::StringRef ArgumentName,
                              const model::DynamicFunction &F) {
  return getArgumentLocation<true>(ArgumentName, F);
}

static std::string getArgumentLocationDefinition(llvm::StringRef ArgumentName,
                                                 const model::Function &F) {
  return getArgumentLocation<true>(ArgumentName, F);
}

std::string getArgumentLocationReference(llvm::StringRef ArgumentName,
                                         const model::Function &F) {
  return getArgumentLocation<false>(ArgumentName, F);
}

template<bool IsDefinition>
static std::string
getVariableLocation(llvm::StringRef VariableName, const model::Function &F) {
  return Tag(tags::Span, VariableName)
    .addAttribute(attributes::Token, tokens::Variable)
    .addAttribute(ptml::locationAttribute(IsDefinition),
                  serializeVariableLocation(VariableName, F))
    .serialize();
}

std::string getVariableLocationDefinition(llvm::StringRef VariableName,
                                          const model::Function &F) {
  return getVariableLocation<true>(VariableName, F);
}

std::string getVariableLocationReference(llvm::StringRef VariableName,
                                         const model::Function &F) {
  return getVariableLocation<false>(VariableName, F);
}

TypeString getReturnField(const model::Type &Function,
                          size_t Index,
                          const model::Binary &Model) {
  const auto Layout = abi::FunctionType::Layout::make(Function);
  llvm::SmallVector<model::QualifiedType>
    ReturnValues = flattenReturnTypes(Layout, Model);
  revng_assert(ReturnValues.size() > Index, "Index out of bounds");
  revng_assert(ReturnValues.size() > 1,
               "This function should only ever be called for return values "
               "that require a struct to be created");
  return TypeString((Twine(RetFieldPrefix) + Twine(Index)).str());
}

TypeString
getNamedCInstance(const model::QualifiedType &QT, StringRef InstanceName) {
  constexpr auto &isConst = model::Qualifier::isConst;
  constexpr auto &isPointer = model::Qualifier::isPointer;

  bool IsUnqualified = QT.Qualifiers().empty();
  bool FirstQualifierIsPointer = IsUnqualified
                                 or isPointer(QT.Qualifiers().front());
  bool PrependWhitespaceToInstanceName = not InstanceName.empty()
                                         and (IsUnqualified
                                              or not FirstQualifierIsPointer);

  const model::Type &Unqualified = *QT.UnqualifiedType().getConst();
  std::string UnqualifiedTypeName = ptml::getLocationReference(Unqualified);

  TypeString Result;

  // Here we have a bunch of pointers, const, and array qualifiers.
  // Because of arrays, we have to emit the types with C infamous clockwise
  // spiral rule. Luckily all our function types have names, so at least this
  // cannot become too nasty.

  auto QIt = QT.Qualifiers().begin();
  auto QEnd = QT.Qualifiers().end();
  do {
    // Accumulate the result that are outside the array.
    TypeString Partial;

    // Find the first qualifer that is an array.
    auto QArrayIt = std::find_if(QIt, QEnd, model::Qualifier::isArray);
    {
      // If we find it, go back to the first previous const-qualifier that
      // const-qualifies the array itself. This is necessary because C does not
      // have const arrays, only arrays of const, so we have to handle
      // const-arrays specially, and emit the const-qualifier on the element in
      // C, even if in the model it was on the array.
      if (QArrayIt != QEnd and QArrayIt != QIt
          and isConst(*std::make_reverse_iterator(QArrayIt)))
        QArrayIt = std::prev(QArrayIt);
    }

    // Emit non-array qualifiers.
    {
      bool PrevPointer = false;
      for (const model::Qualifier &Q :
           llvm::reverse(llvm::make_range(QIt, QArrayIt))) {
        if (not PrevPointer)
          Partial.append(" ");

        switch (Q.Kind()) {

        case model::QualifierKind::Const:
          Partial.append(keywords::Const.serialize());
          PrevPointer = false;
          break;
        case model::QualifierKind::Pointer:
          Partial.append(Tag(tags::Span, "*")
                           .addAttribute(attributes::Token, tokens::Operator)
                           .serialize());
          PrevPointer = true;
          break;

        default:
          revng_abort();
        }
      }
    }

    // Print the actual instance name.
    if (QIt == QT.Qualifiers().begin()) {
      if (PrependWhitespaceToInstanceName)
        Partial.append(" ");
      Result.append(InstanceName.str());
    }

    // Now we can prepend the qualifiers that are outside the array to the
    // Result string. This always work because at this point Result holds
    // whatever is left from previous iteration, so it's either empty, or it
    // starts with '(' because we're using the clockwise spiral rule.
    Result = (Twine(Partial) + Twine(Result)).str();

    // After this point we'll only be emitting parenthesis for the clockwise
    // spiral rule, or append square brackets at the end of Result for arrays.

    // Find the next non-array qualifier. Skip over const-qualifiers, because in
    // C there are no const-arrays, so we'll have to deal with const-arrays
    // separately.
    auto QPointerIt = std::find_if(QArrayIt, QEnd, model::Qualifier::isPointer);
    {
      // If we find the next pointer qualifier, go back to the first previous
      // const-qualifier that const-qualifies the pointer itself. This is
      // necessary, so that we can reason about the element of the array being
      // const, and we can deal properly with const arrays.
      if (QPointerIt != QEnd and QPointerIt != QArrayIt
          and isConst(*std::make_reverse_iterator(QPointerIt)))
        QPointerIt = std::prev(QPointerIt);
    }

    if (QArrayIt != QPointerIt) {
      // If QT is s a pointer to an array we have to add parentheses for the
      // clockwise spiral rule
      auto ReverseQArrayIt = std::make_reverse_iterator(QArrayIt);
      bool LastWasPointer = QArrayIt != QIt and isPointer(*ReverseQArrayIt);
      if (LastWasPointer)
        Result = (Twine("(") + Twine(Result) + Twine(")")).str();

      const auto &ArrayOrConstRange = llvm::make_range(QArrayIt, QPointerIt);
      bool ConstQualifiedArray = llvm::any_of(ArrayOrConstRange, isConst);

      // If the array is const-qualfied and its element is not const-qualified,
      // just print it as an array of const-qualified elements, because that's
      // the equivalent semantics in C anyway.
      if (ConstQualifiedArray) {
        bool ElementIsConstQualified = QPointerIt != QEnd
                                       and isConst(*QPointerIt);
        // If the array is const qualified but the element is not, we have to
        // force const-ness onto the element, because in C there's no way to
        // const-qualify arrays. If the element is already const-qualified, then
        // there's no need to do that, because we're still gonna print the
        // const-qualifier for the element.
        if (not ElementIsConstQualified) {

          const auto &Const = keywords::Const.serialize();
          Result = (Twine(" ") + Twine(Const) + Twine(" ") + Twine(Result))
                     .str();
        }
      }

      for (const model::Qualifier &ArrayQ :
           llvm::reverse(llvm::make_filter_range(ArrayOrConstRange,
                                                 model::Qualifier::isArray)))
        Result.append((Twine("[") + Twine(ArrayQ.Size()) + Twine("]")).str());
    }

    QIt = QPointerIt;
  } while (QIt != QEnd);

  Result = (Twine(UnqualifiedTypeName) + Twine(Result)).str();

  return Result;
}

TypeString getArrayWrapper(const model::QualifiedType &QT) {
  revng_assert(QT.isArray());
  TypeString Result;
  Result.append(ArrayWrapperPrefix);

  for (const auto &Qualifier : QT.Qualifiers()) {

    switch (Qualifier.Kind()) {

    case model::QualifierKind::Const: {
      Result.append("const_");
    } break;

    case model::QualifierKind::Pointer: {
      Result.append("ptr_to_");
    } break;

    case model::QualifierKind::Array: {
      auto NElem = Qualifier.Size();
      Result.append(("array_" + Twine(NElem) + "_of_").str());
    } break;

    default:
      revng_abort();
    }
  }

  Result.append(QT.UnqualifiedType().get()->name());
  Tag ResultTag = Tag(tags::Span, Result.str());
  return TypeString(ResultTag.serialize());
}

TypeString getNamedInstanceOfReturnType(const model::Type &Function,
                                        llvm::StringRef InstanceName) {
  TypeString Result;

  const auto Layout = abi::FunctionType::Layout::make(Function);
  if (Layout.returnsAggregateType()) {
    revng_assert(not Layout.Arguments.empty());
    auto &ShadowArgument = Layout.Arguments[0];
    using namespace abi::FunctionType::ArgumentKind;
    revng_assert(ShadowArgument.Kind == ShadowPointerToAggregateReturnValue);
    Result = getNamedCInstance(stripPointer(ShadowArgument.Type), InstanceName);
  } else {
    if (Layout.ReturnValues.size() == 0) {
      Result = Tag(tags::Span, "void")
                 .addAttribute(attributes::Token, tokens::Type)
                 .serialize();
      if (not InstanceName.empty())
        Result.append((Twine(" ") + Twine(InstanceName)).str());
    } else if (Layout.ReturnValues.size() == 1) {
      auto RetTy = Layout.ReturnValues.front().Type;
      // When returning arrays, they need to be wrapped into an artificial
      // struct
      if (RetTy.isArray()) {
        Result = getArrayWrapper(RetTy);
        if (not InstanceName.empty())
          Result.append((Twine(" ") + Twine(InstanceName)).str());
      } else {
        Result = getNamedCInstance(RetTy, InstanceName);
      }
    } else {
      // RawFunctionTypes can return multiple values, which need to be wrapped
      // in a struct
      revng_assert(llvm::isa<model::RawFunctionType>(Function));
      Result = ptml::tokenTag((Twine(RetStructPrefix) + "returned_by_"
                               + model::Identifier::fromString(Function.name()))
                                .str(),
                              tokens::Type)
                 .serialize();
      if (not InstanceName.empty())
        Result.append((Twine(" ") + Twine(InstanceName)).str());
    }
  }

  revng_assert(not llvm::StringRef(Result).trim().empty());
  return Result;
}

template<ModelFunction FunctionType>
static void printFunctionPrototypeImpl(const FunctionType *Function,
                                       const model::RawFunctionType &RF,
                                       const llvm::StringRef &FunctionName,
                                       llvm::raw_ostream &Header,
                                       const model::Binary &Model,
                                       bool Declaration) {
  auto Layout = abi::FunctionType::Layout::make(RF);
  revng_assert(not Layout.returnsAggregateType());

  Header << getNamedInstanceOfReturnType(RF, FunctionName);

  revng_assert(RF.StackArgumentsType().Qualifiers().empty());
  if (RF.Arguments().empty()
      and not RF.StackArgumentsType().UnqualifiedType().isValid()) {
    Header << "(" << ptml::tokenTag("void", tokens::Type) << ")";
  } else {
    const StringRef Open = "(";
    const StringRef Comma = ", ";
    StringRef Separator = Open;
    for (const auto &Arg : RF.Arguments()) {
      auto ArgName = model::Identifier::fromString(Arg.name()).str().str();
      std::string ArgString = Function ?
                                getArgumentLocationDefinition(ArgName,
                                                              *Function) :
                                "";
      Header << Separator << getNamedCInstance(Arg.Type(), ArgString);
      Separator = Comma;
    }

    revng_assert(RF.StackArgumentsType().Qualifiers().empty());
    if (RF.StackArgumentsType().UnqualifiedType().isValid()) {
      // Add last argument representing a pointer to the stack arguments
      auto StackArgName = Function ? getArgumentLocationDefinition("stack_args",
                                                                   *Function) :
                                     "";
      Header << Separator
             << getNamedCInstance(RF.StackArgumentsType(), StackArgName);
    }
    Header << ")";
  }
}

template<ModelFunction FunctionType>
static void printFunctionPrototypeImpl(const FunctionType *Function,
                                       const model::CABIFunctionType &CF,
                                       const llvm::StringRef &FunctionName,
                                       llvm::raw_ostream &Header,
                                       const model::Binary &Model,
                                       bool Declaration) {
  Header << getNamedInstanceOfReturnType(CF, FunctionName);

  if (CF.Arguments().empty()) {
    Header << "(" << ptml::tokenTag("void", tokens::Type) << ")";
  } else {
    const StringRef Open = "(";
    const StringRef Comma = ", ";
    StringRef Separator = Open;

    for (const auto &Arg : CF.Arguments()) {
      auto ArgName = model::Identifier::fromString(Arg.name()).str().str();
      std::string ArgString = Function ?
                                getArgumentLocationDefinition(ArgName,
                                                              *Function) :
                                "";
      TypeString ArgDeclaration;
      if (Arg.Type().isArray()) {
        ArgDeclaration = getArrayWrapper(Arg.Type());
        if (not ArgString.empty()) {
          ArgDeclaration.append(" ");
          ArgDeclaration.append(ArgString);
        }
      } else {
        ArgDeclaration = getNamedCInstance(Arg.Type(), ArgString);
      }
      Header << Separator << ArgDeclaration;
      Separator = Comma;
    }
    Header << ")";
  }
}

void printFunctionPrototype(const model::Type &FT,
                            const model::Function &Function,
                            llvm::raw_ostream &Header,
                            const model::Binary &Model,
                            bool Declaration) {

  Tag FunctionTag = ptml::tokenTag(Function.name(), tokens::Function)
                      .addAttribute(attributes::ModelEditPath,
                                    getCustomNamePath(Function))
                      .addAttribute(ptml::locationAttribute(Declaration),
                                    serializedLocation(ranks::Function,
                                                       Function.key()));
  if (auto *RF = dyn_cast<model::RawFunctionType>(&FT)) {
    printFunctionPrototypeImpl(&Function,
                               *RF,
                               FunctionTag.serialize(),
                               Header,
                               Model,
                               Declaration);
  } else if (auto *CF = dyn_cast<model::CABIFunctionType>(&FT)) {
    printFunctionPrototypeImpl(&Function,
                               *CF,
                               FunctionTag.serialize(),
                               Header,
                               Model,
                               Declaration);
  } else {
    revng_abort();
  }
}

void printFunctionPrototype(const model::Type &FT,
                            const model::DynamicFunction &Function,
                            llvm::raw_ostream &Header,
                            const model::Binary &Model,
                            bool Declaration) {
  Tag FunctionTag = ptml::tokenTag(Function.name(), tokens::Function)
                      .addAttribute(attributes::ModelEditPath,
                                    getCustomNamePath(Function))
                      .addAttribute(ptml::locationAttribute(Declaration),
                                    serializedLocation(ranks::DynamicFunction,
                                                       Function.key()));
  if (auto *RF = dyn_cast<model::RawFunctionType>(&FT)) {
    printFunctionPrototypeImpl(&Function,
                               *RF,
                               FunctionTag.serialize(),
                               Header,
                               Model,
                               Declaration);
  } else if (auto *CF = dyn_cast<model::CABIFunctionType>(&FT)) {
    printFunctionPrototypeImpl(&Function,
                               *CF,
                               FunctionTag.serialize(),
                               Header,
                               Model,
                               Declaration);
  } else {
    revng_abort();
  }
}

void printFunctionTypeDeclaration(const model::Type &FT,
                                  llvm::raw_ostream &Header,
                                  const model::Binary &Model) {

  auto TypeName = ptml::getLocationDefinition(FT);
  if (auto *RF = dyn_cast<model::RawFunctionType>(&FT)) {
    printFunctionPrototypeImpl<model::Function>(nullptr,
                                                *RF,
                                                TypeName,
                                                Header,
                                                Model,
                                                true);
  } else if (auto *CF = dyn_cast<model::CABIFunctionType>(&FT)) {
    printFunctionPrototypeImpl<model::Function>(nullptr,
                                                *CF,
                                                TypeName,
                                                Header,
                                                Model,
                                                true);
  } else {
    revng_abort();
  }
}