Stop masking NTTP arguments (#534)

Closes #435

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -139,6 +139,28 @@ std::string Converter::GetUnboxedTypeAsString(clang::QualType qual_type) {
   return ToString(qual_type);
 }
 
+std::string
+Converter::GetTemplateArgumentAsString(const clang::TemplateArgument &arg) {
+  switch (arg.getKind()) {
+  case clang::TemplateArgument::Type:
+    return GetUnboxedTypeAsString(arg.getAsType());
+  case clang::TemplateArgument::Integral:
+  case clang::TemplateArgument::NullPtr:
+  case clang::TemplateArgument::Declaration:
+  case clang::TemplateArgument::StructuralValue: {
+    auto expr = GetSema().BuildExpressionFromNonTypeTemplateArgument(
+        arg, clang::SourceLocation());
+    assert(expr.isUsable() && "cannot build non-type template argument");
+    Buffer buf(*this);
+    Convert(expr.get());
+    return std::move(buf).str();
+  }
+  default:
+    assert(0 && "template parameter is not bound to a type or a value");
+    return {};
+  }
+}
+
 bool Converter::ConvertMappedType(clang::QualType qual_type) {
   std::string type_as_string = Mapper::Map(*this, qual_type);
   if (type_as_string == token::kIgnoreRule) {
@@ -747,6 +769,10 @@ bool Converter::IsPassThroughRule(clang::Expr *expr) const {
 }
 
 bool Converter::RecordDerivesCopy(const clang::RecordDecl *decl) {
+  if (auto cxx = llvm::dyn_cast<clang::CXXRecordDecl>(decl);
+      cxx && cxx->isLambda()) {
+    return false;
+  }
   if (auto rule =
           RuleRegistry::Search(ctx_, ctx_.getCanonicalTagType(decl)).first) {
     auto &derives = rule->type_info.derives;

cpp2rust/converter/converter.h

@@ -63,6 +63,8 @@ class Converter : public clang::RecursiveASTVisitor<Converter> {
 
   virtual std::string GetUnboxedTypeAsString(clang::QualType qual_type);
 
+  std::string GetTemplateArgumentAsString(const clang::TemplateArgument &arg);
+
   bool VisitRecoveryExpr(clang::RecoveryExpr *expr);
 
   virtual void EmitFilePreamble();

cpp2rust/converter/printer.cpp

@@ -8,10 +8,8 @@
 #include <clang/Basic/SourceManager.h>
 #include <clang/Lex/Lexer.h>
 
-#include <array>
 #include <cctype>
 #include <format>
-#include <regex>
 #include <string_view>
 #include <utility>
 
@@ -78,24 +76,6 @@ clang::QualType normalizeQualType(clang::ASTContext &ctx,
       ctx);
 }
 
-std::string normalizeTranslationRule(std::string rule) {
-  // Detach pointer from double reference. Useful for matching translation
-  // rules.
-  ReplaceAll(rule, "*&&", "* &&");
-
-  static const std::array<std::pair<std::regex, std::string>, 1>
-      normalization_rules{{
-          // Ignore constant template parameters, i.e. replace them with _.
-          {std::regex(R"(\b\d+\b)"), "_"},
-      }};
-
-  for (const auto &r : normalization_rules) {
-    rule = std::regex_replace(rule, r.first, r.second);
-  }
-
-  return rule;
-}
-
 } // namespace
 
 std::string ToRustName(std::string name) {
@@ -171,7 +151,7 @@ std::string ToString(clang::ASTContext &ctx, clang::QualType qual_type,
       std::string out;
       llvm::raw_string_ostream os(out);
       ctx.getPointerType(pointee).print(os, getPrintPolicy(ctx));
-      return normalizeTranslationRule(std::move(out));
+      return out;
     }
   }
 
@@ -200,7 +180,7 @@ std::string ToString(clang::ASTContext &ctx, clang::QualType qual_type,
   std::string type;
   llvm::raw_string_ostream os(type);
   normalizeQualType(ctx, qual_type).print(os, getPrintPolicy(ctx));
-  return normalizeTranslationRule(std::move(type));
+  return type;
 }
 
 std::string ToString(clang::ASTContext &ctx, const clang::NamedDecl *decl) {
@@ -237,7 +217,7 @@ std::string ToString(clang::ASTContext &ctx, const clang::NamedDecl *decl) {
 
   if (!func_decl) {
     decl->printQualifiedName(os, getPrintPolicy(ctx));
-    return normalizeTranslationRule(std::move(out));
+    return out;
   }
 
   os << ToString(ctx, func_decl->getReturnType()) << ' ';
@@ -324,7 +304,7 @@ std::string ToString(clang::ASTContext &ctx, const clang::NamedDecl *decl) {
     }
   }
 
-  return normalizeTranslationRule(std::move(out));
+  return out;
 }
 
 std::string ToString(clang::ASTContext &ctx, const clang::Expr *expr) {

cpp2rust/converter/rules/matcher.cpp

@@ -12,22 +12,20 @@ namespace cpp2rust::Matcher {
 
 std::string MapBinding(Converter &converter, const Bindings &bindings,
                        unsigned n) {
-  auto type = bindings.at(n);
-  assert(!type.isNull() && "template parameter is not bound to a type");
-  return converter.GetUnboxedTypeAsString(type);
+  return converter.GetTemplateArgumentAsString(bindings.at(n));
 }
 
-// Substitutes concrete types into a target template string using the provided
-// type mapping. Each template parameter in `tgt_template` is replaced with its
-// corresponding instantiated type from `types`.
+// Substitutes template arguments into a target template string. Each template
+// parameter in `tgt_template` is replaced with its corresponding argument from
+// `bindings`, which is either a type or a value.
 //
 // Example:
-//   types        = { int }
-//   tgt_template = "Vec<T1>"
-//   result       = "Vec<i32>"
-std::string InstantiateTgt(Converter &converter, const Bindings &types,
+//   bindings     = { int, 4 }
+//   tgt_template = "[T1; T2]"
+//   result       = "[i32; 4_usize]"
+std::string InstantiateTgt(Converter &converter, const Bindings &bindings,
                            const std::string &tgt_template) {
-  assert(types.size() <= TranslationRule::kMaxGenerics &&
+  assert(bindings.size() <= TranslationRule::kMaxGenerics &&
          "template placeholder exceeds kMaxGenerics");
   std::string instantiated_template = tgt_template;
   std::string::size_type pos = 0;
@@ -40,7 +38,7 @@ std::string InstantiateTgt(Converter &converter, const Bindings &types,
       continue;
     }
     auto repl =
-        MapBinding(converter, types, instantiated_template[pos + 1] - '1');
+        MapBinding(converter, bindings, instantiated_template[pos + 1] - '1');
     instantiated_template.replace(pos, 2, repl);
     pos += repl.length();
   }

cpp2rust/converter/rules/matcher.h

@@ -6,7 +6,7 @@
 #include <clang/AST/ASTContext.h>
 #include <clang/AST/Decl.h>
 #include <clang/AST/Expr.h>
-#include <clang/AST/Type.h>
+#include <clang/AST/TemplateBase.h>
 
 #include <string>
 #include <utility>
@@ -19,13 +19,13 @@ class Converter;
 }
 
 namespace cpp2rust::Matcher {
-using Bindings = std::vector<clang::QualType>;
+using Bindings = std::vector<clang::TemplateArgument>;
 
 template <typename Rule> using Match = std::pair<Rule *, Bindings>;
 
 std::string MapBinding(Converter &converter, const Bindings &bindings,
                        unsigned n);
 
-std::string InstantiateTgt(Converter &converter, const Bindings &types,
+std::string InstantiateTgt(Converter &converter, const Bindings &bindings,
                            const std::string &tgt_template);
 } // namespace cpp2rust::Matcher

cpp2rust/converter/rules/registry.cpp

@@ -265,11 +265,11 @@ Matcher::Bindings getBindings(const clang::NamedDecl *rule,
     auto name = params->getParam(i)->getName();
     unsigned n = 0;
     if (!name.consume_front("T") || name.getAsInteger(10, n) ||
-        args[i].getKind() != clang::TemplateArgument::Type) {
+        args[i].getKind() == clang::TemplateArgument::Pack) {
       continue;
     }
     bindings.resize(std::max<size_t>(bindings.size(), n));
-    bindings[n - 1] = args[i].getAsType();
+    bindings[n - 1] = args[i];
   }
   return bindings;
 }

cpp2rust/converter/rules/rules_loader.cpp

@@ -237,6 +237,8 @@ class RuleUsageCollector
       case clang::TemplateArgument::Null:
       case clang::TemplateArgument::Integral:
       case clang::TemplateArgument::NullPtr:
+      case clang::TemplateArgument::Declaration:
+      case clang::TemplateArgument::StructuralValue:
       case clang::TemplateArgument::Expression:
       case clang::TemplateArgument::Template:
         break;

rules/pair/src.cpp

@@ -48,3 +48,19 @@ template <typename T1, typename T2> const T2 &f15(const std::pair<T1, T2> &a0) {
 template <typename T1, typename T2> const T1 &f16(const std::pair<T1, T2> &a0) {
   return a0.first;
 }
+
+template <typename T1, typename T2> T1 &f17(std::pair<T1, T2> &a0) {
+  return std::get<0>(a0);
+}
+
+template <typename T1, typename T2> T2 &f18(std::pair<T1, T2> &a0) {
+  return std::get<1>(a0);
+}
+
+template <typename T1, typename T2> const T1 &f19(const std::pair<T1, T2> &a0) {
+  return std::get<0>(a0);
+}
+
+template <typename T1, typename T2> const T2 &f20(const std::pair<T1, T2> &a0) {
+  return std::get<1>(a0);
+}

rules/pair/tgt_refcount.rs

@@ -68,3 +68,19 @@ fn f15<T1, T2>(a0: (Value<T1>, Value<T2>)) -> Value<T2> {
 fn f16<T1, T2>(a0: (Value<T1>, Value<T2>)) -> Value<T1> {
     a0.0
 }
+
+fn f17<T1, T2>(a0: (Value<T1>, Value<T2>)) -> Ptr<T1> {
+    a0.0.as_pointer()
+}
+
+fn f18<T1, T2>(a0: (Value<T1>, Value<T2>)) -> Ptr<T2> {
+    a0.1.as_pointer()
+}
+
+fn f19<T1, T2>(a0: (Value<T1>, Value<T2>)) -> Ptr<T1> {
+    a0.0.as_pointer()
+}
+
+fn f20<T1, T2>(a0: (Value<T1>, Value<T2>)) -> Ptr<T2> {
+    a0.1.as_pointer()
+}

rules/pair/tgt_unsafe.rs

@@ -37,3 +37,19 @@ unsafe fn f15<T1, T2>(a0: (T1, T2)) -> T2 {
 unsafe fn f16<T1, T2>(a0: (T1, T2)) -> T1 {
     a0.0
 }
+
+unsafe fn f17<T1, T2>(a0: &mut (T1, T2)) -> *mut T1 {
+    &mut a0.0
+}
+
+unsafe fn f18<T1, T2>(a0: &mut (T1, T2)) -> *mut T2 {
+    &mut a0.1
+}
+
+unsafe fn f19<T1, T2>(a0: &(T1, T2)) -> *const T1 {
+    &a0.0
+}
+
+unsafe fn f20<T1, T2>(a0: &(T1, T2)) -> *const T2 {
+    &a0.1
+}