Add ipr::FunctionTraits (#309)

And support for _explicit object parameter_ description in the IR.

Author: GabrielDosReis

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(
-   VERSION 3.28
+   VERSION 3.31
 )
 include(CheckIPOSupported)
 
@@ -59,7 +59,7 @@ target_sources(${PROJECT_NAME}
 
 set_target_properties(${PROJECT_NAME}
    PROPERTIES
-      CXX_STANDARD 20
+      CXX_STANDARD 23
       CXX_STANDARD_REQUIRED ON
 	   CXX_EXTENSIONS OFF
 )

include/ipr/impl

@@ -1965,11 +1965,21 @@ namespace ipr::impl {
       const ipr::Region& lexical_region() const final { return lexreg.get(); }
    };
 
+   struct Concept : impl::Decl<ipr::Concept> {
+      impl::Parameter_list inputs;
+      util::ref<const ipr::Expr> init;
+      explicit Concept(const ipr::Region& r) : inputs{r, { }} { }
+      const ipr::Parameter_list& parameters() const final { return inputs; }
+      const ipr::Expr& result() const final { return init.get(); }
+      Optional<ipr::Expr> initializer() const final { return { *this }; }
+   };
+
    // For a non-defining function declaration, the parameters - if any is named
    // or has a default argument - are stored with that particular declaration.
    // A function definition is one that specifies the initializer (Mapping) which
    // already has room for the named parameters or the default arguments.
    struct fundecl_data : std::variant<impl::Parameter_list*, impl::Mapping*> {
+      ipr::FunctionTraits traits { };
       impl::Parameter_list* parameters() const { return std::get<0>(*this); }
       impl::Mapping* mapping() const { return std::get<1>(*this); }
    };
@@ -1980,6 +1990,7 @@ namespace ipr::impl {
 
       Fundecl();
 
+      ipr::FunctionTraits traits() const final { return data.traits; }
       const ipr::Parameter_list& parameters() const final;
       Optional<ipr::Mapping> mapping() const final;
       Optional<ipr::Expr> initializer() const final;

include/ipr/interface

@@ -81,8 +81,9 @@ namespace ipr {
 #include <ipr/node-category>
    };
 
-   // -- General structural utility types.
+   // -- General structural utility types and functions.
 
+   // -- General node category class.
    template<Category_code Cat, class T = Expr>
    struct Category : T {
    protected:
@@ -102,6 +103,33 @@ namespace ipr {
       virtual const T& result() const = 0;
    };
 
+                                // -- DeclSpecifiers --
+   enum class DeclSpecifiers : std::uint32_t {
+      None       = 0,
+      Register   = 1 << 0,   // Banned from C++17.
+      Static     = 1 << 1,
+      Extern     = 1 << 2,
+      Mutable    = 1 << 3,
+      Thread     = 1 << 4,
+      StorageClass  = Register | Static | Extern | Mutable | Thread,
+
+      Inline     = 1 << 5,
+      Virtual    = 1 << 6,   // also used as storage class specifier
+                             // for virtual base subobjects
+      Explicit   = 1 << 7,
+
+      Friend     = 1 << 9,
+      Typedef    = 1 << 10,
+
+      Public     = 1 << 11,
+      Protected  = 1 << 12,
+      Private    = 1 << 13,
+      AccessProtection = Public | Protected | Private,
+
+      Export     = 1 << 14,  // For exported declarations.
+      Constexpr  = 1 << 15,  // C++ 11
+   };
+
    // -- Logogram --
    // A class of words (from a C++ input source) standing for themselves, with no particular elaboration.
    struct Logogram : Basic_unary<const String&> {
@@ -245,12 +273,13 @@ namespace ipr {
    }
 
                                  // -- Lambda_specifiers --
-   // Declaration specifiers that can appear on a lambda expression.
+   // Declaration specifiers that can appear in a lambda expression.
    enum class Lambda_specifiers : std::uint32_t {
       None = 0,
-      Mutable    = 1 << 0,
-      Constexpr  = 1 << 1,
-      Consteval  = 1 << 2,
+      Mutable    = 1 << 0,                   // `mutable` lambda
+      Constexpr  = 1 << 1,                   // `constexpr` lambda
+      Consteval  = 1 << 2,                   // `consteval` lambda
+      ExplicitObject = 1 << 3,               // explicit object parameter `this`.
    };
 
                                 // -- Module_name --
@@ -1841,15 +1870,33 @@ namespace ipr {
       Optional<Expr> initializer() const final { return { }; }
    };
 
+   // -- Semantic traits of a function declaration.
+   enum class FunctionTraits : std::uint32_t {
+      Nothing  = 0x0,                     // No particular traits
+      Pure     = 1 << 0,                  // pure virtual function
+      Virtual  = 1 << 1,                  // virtual function
+      Static   = 1 << 2,                  // static member-function, NOT linkage
+      Inline   = 1 << 3,                  // inline function
+      Explicit = 1 << 4,                  // function declared `explicit`
+      Constexpr = 1 << 5,                 // constexpr function
+      Consteval = 1 << 6,                 // consteval function
+      ExplicitObject = 1 << 7,            // function with explicit object parameter.
+   };
+
                                 // -- Fundecl --
    // This node represents a function declaration. Notice that the
    // exception specification is actually made part of the function type.
    struct Fundecl : Category<Category_code::Fundecl, Decl> {
+      virtual FunctionTraits traits() const = 0;
       virtual Optional<Mapping> mapping() const = 0;
       virtual const Parameter_list& parameters() const = 0;
       virtual Optional<Fundecl> definition() const = 0;
    };
 
+                                // -- Concept --
+   struct Concept : Category<Category_code::Concept, Decl>, Parameterization<Expr> {
+   };
+
                                 // -- Var --
    // This represents a variable declaration.  It is also used to
    // represent a static data member.
@@ -2152,6 +2199,7 @@ namespace ipr {
       virtual void visit(const Field&);
       virtual void visit(const Fundecl&);
       virtual void visit(const Template&);
+      virtual void visit(const Concept&);
       virtual void visit(const Parameter&);
       virtual void visit(const Parameter_list&);
       virtual void visit(const Typedecl&);

include/ipr/node-category

@@ -177,6 +177,7 @@ Field,                              // ipr::Field
 Bitfield,                           // ipr::Bitfield
 Fundecl,                            // ipr::Fundecl
 Template,                           // ipr::Template
+Concept,                            // ipr::Concept
 Parameter,                          // ipr::Parameter
 Typedecl,                           // ipr::Typedecl
 Var,                                // ipr::Var

include/ipr/synopsis

@@ -220,6 +220,7 @@ namespace ipr {
    struct Bitfield;              // bitfield
    struct Fundecl;               // function-declaration
    struct Template;              // template-declaration
+   struct Concept;               // concept definition
    struct Parameter;             // function or template parameter
    struct Typedecl;              // declaration for a type
    struct Var;                   // variable declaration

src/traversal.cxx

@@ -979,6 +979,11 @@ ipr::Visitor::visit(const Fundecl& d)
    visit(as<Decl>(d));
 }
 
+void ipr::Visitor::visit(const Concept& d)
+{
+   visit(as<Decl>(d));
+}
+
 void
 ipr::Visitor::visit(const Parameter& d)
 {