Add refcount support for va_args

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -358,17 +358,22 @@ bool Converter::VisitFunctionTemplateDecl(clang::FunctionTemplateDecl *decl) {
   return false;
 }
 
+void Converter::ConvertVaListVarDecl(clang::VarDecl *decl) {
+  if (clang::isa<clang::ParmVarDecl>(decl)) {
+    // va_list parameter (decayed to __va_list_tag *): emit "mut ap: VaList"
+  } else {
+    // va_list local variable: emit "let mut ap: VaList"
+    StrCat(keyword::kLet);
+  }
+  StrCat(keyword_mut_, GetNamedDeclAsString(decl), token::kColon, "VaList");
+}
+
 bool Converter::ConvertVarDeclSkipInit(clang::VarDecl *decl) {
   auto qual_type = decl->getType();
   auto name = GetNamedDeclAsString(decl);
 
   if (IsVaListType(ctx_, qual_type) && decl->isLocalVarDecl()) {
-    if (!clang::isa<clang::ParmVarDecl>(decl)) {
-      // va_list local variable: emit "let mut ap: VaList"
-      StrCat(keyword::kLet);
-    } // else va_list parameter (decayed to __va_list_tag *): emit "mut ap:
-      // VaList"
-    StrCat(keyword_mut_, name, token::kColon, "VaList");
+    ConvertVaListVarDecl(decl);
     return true;
   }
 
@@ -429,9 +434,7 @@ void Converter::ConvertVarDecl(clang::VarDecl *decl) {
     return;
   }
   auto qual_type = decl->getType();
-  if (IsVaListType(ctx_, qual_type)) {
-    StrCat(token::kAssign, "VaList::empty()");
-  } else if (decl->hasInit()) {
+  if (decl->hasInit()) {
     StrCat(token::kAssign);
     ConvertVarInit(qual_type, decl->getInit());
   } else if (!clang::isa<clang::ParmVarDecl>(decl)) {

cpp2rust/converter/converter.h

@@ -85,7 +85,9 @@ class Converter : public clang::RecursiveASTVisitor<Converter> {
 
   virtual void ConvertGlobalVarDecl(clang::VarDecl *decl);
 
-  bool ConvertVarDeclSkipInit(clang::VarDecl *decl);
+  virtual void ConvertVaListVarDecl(clang::VarDecl *decl);
+
+  virtual bool ConvertVarDeclSkipInit(clang::VarDecl *decl);
 
   virtual bool ConvertLambdaVarDecl(clang::VarDecl *decl);
 
@@ -199,7 +201,7 @@ class Converter : public clang::RecursiveASTVisitor<Converter> {
 
   virtual void ConvertPrintf(clang::CallExpr *expr);
 
-  virtual void ConvertVAArgCall(clang::CallExpr *expr);
+  void ConvertVAArgCall(clang::CallExpr *expr);
 
   virtual bool VisitCallExpr(clang::CallExpr *expr);
 

cpp2rust/converter/models/converter_refcount.cpp

@@ -172,6 +172,11 @@ bool ConverterRefCount::VisitPointerType(clang::PointerType *type) {
     return false;
   }
 
+  if (IsVaListType(ctx_, clang::QualType(type, 0))) {
+    StrCat("VaList");
+    return false;
+  }
+
   if (type->isVoidPointerType()) {
     StrCat("AnyPtr");
     return false;
@@ -472,6 +477,17 @@ void ConverterRefCount::EmitFunctionPreamble(clang::FunctionDecl *decl) {
   }
 }
 
+void ConverterRefCount::ConvertVaListVarDecl(clang::VarDecl *decl) {
+  if (clang::isa<clang::ParmVarDecl>(decl)) {
+    // va_list parameter (decayed to __va_list_tag *): emit "mut ap: VaList"
+  } else {
+    // va_list local variable: emit "let mut ap: VaList"
+    StrCat(keyword::kLet);
+  }
+
+  StrCat(GetNamedDeclAsString(decl), token::kColon, "Value<VaList>");
+}
+
 bool ConverterRefCount::ConvertLambdaVarDecl(clang::VarDecl *decl) {
   return false;
 }
@@ -775,6 +791,11 @@ void ConverterRefCount::ConvertPrintf(clang::CallExpr *expr) {
 }
 
 bool ConverterRefCount::VisitCallExpr(clang::CallExpr *expr) {
+  if (IsBuiltinVaStart(expr) || IsBuiltinVaEnd(expr) || IsBuiltinVaCopy(expr)) {
+    ConvertVAArgCall(expr);
+    return false;
+  }
+
   if (expr->isCallToStdMove()) {
     if (IsUniquePtr(expr->getArg(0)->getType())) {
       StrCat(std::format("{}.take()", ConvertLValue(expr->getArg(0))));
@@ -912,6 +933,10 @@ bool ConverterRefCount::VisitImplicitCastExpr(clang::ImplicitCastExpr *expr) {
   }
 
   if (expr->getCastKind() == clang::CastKind::CK_ArrayToPointerDecay) {
+    if (IsVaListType(ctx_, sub_expr->getType())) {
+      Convert(sub_expr);
+      return false;
+    }
     if (clang::isa<clang::StringLiteral>(sub_expr) ||
         clang::isa<clang::PredefinedExpr>(sub_expr)) {
       StrCat(std::format("Ptr::from_string_literal({})", ToString(sub_expr)));
@@ -1366,6 +1391,18 @@ bool ConverterRefCount::VisitImplicitValueInitExpr(
   return Converter::VisitImplicitValueInitExpr(expr);
 }
 
+bool ConverterRefCount::VisitVAArgExpr(clang::VAArgExpr *expr) {
+  auto va_list_expr = expr->getSubExpr();
+  if (auto *cast = clang::dyn_cast<clang::ImplicitCastExpr>(va_list_expr)) {
+    va_list_expr = cast->getSubExpr();
+  }
+  StrCat(ConvertLValue(va_list_expr));
+  StrCat(".arg::<");
+  Convert(expr->getType());
+  StrCat(">()");
+  return false;
+}
+
 bool ConverterRefCount::VisitCXXDefaultArgExpr(clang::CXXDefaultArgExpr *expr) {
   return Converter::VisitCXXDefaultArgExpr(expr);
 }

cpp2rust/converter/models/converter_refcount.h

@@ -47,6 +47,8 @@ class ConverterRefCount final : public Converter {
 
   void ConvertGlobalVarDecl(clang::VarDecl *decl) override;
 
+  void ConvertVaListVarDecl(clang::VarDecl *decl) override;
+
   bool ConvertLambdaVarDecl(clang::VarDecl *decl) override;
 
   bool VisitDeclRefExpr(clang::DeclRefExpr *expr) override;
@@ -93,6 +95,8 @@ class ConverterRefCount final : public Converter {
 
   bool VisitImplicitValueInitExpr(clang::ImplicitValueInitExpr *expr) override;
 
+  bool VisitVAArgExpr(clang::VAArgExpr *expr) override;
+
   void ConvertArrayCXXConstructExpr(clang::CXXConstructExpr *expr) override;
 
   bool VisitCXXDefaultArgExpr(clang::CXXDefaultArgExpr *expr) override;