Traverse the typedef/adjust chain to check va_list

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -69,6 +69,12 @@ bool Converter::Convert(clang::QualType qual_type) {
     return false;
   }
 
+  // Catch va_list before desugaring
+  if (IsVaListType(qual_type)) {
+    StrCat("VaList");
+    return false;
+  }
+
   qual_type = qual_type.getUnqualifiedType().getDesugaredType(ctx_);
   return TraverseType(qual_type);
 }
@@ -243,7 +249,7 @@ bool Converter::VisitPointerType(clang::PointerType *type) {
     return false;
   }
 
-  if (IsVaListType(ctx_, clang::QualType(type, 0))) {
+  if (IsVaListType(clang::QualType(type, 0))) {
     StrCat("VaList");
     return false;
   }
@@ -371,7 +377,7 @@ bool Converter::ConvertVarDeclSkipInit(clang::VarDecl *decl) {
   auto qual_type = decl->getType();
   auto name = GetNamedDeclAsString(decl);
 
-  if (IsVaListType(ctx_, qual_type) && decl->isLocalVarDecl()) {
+  if (IsVaListType(qual_type) && decl->isLocalVarDecl()) {
     ConvertVaListVarDecl(decl);
     return true;
   }
@@ -1641,7 +1647,7 @@ bool Converter::VisitImplicitCastExpr(clang::ImplicitCastExpr *expr) {
       return Convert(sub_expr);
     }
     // __va_list_tag [1] decays to __va_list_tag *. Just pass through by value
-    if (IsVaListType(ctx_, sub_expr->getType())) {
+    if (IsVaListType(sub_expr->getType())) {
       Convert(sub_expr);
       break;
     }
@@ -2650,6 +2656,11 @@ Converter::GetFunctionPointerDefaultAsString(clang::QualType qual_type) {
 }
 
 std::string Converter::GetDefaultAsString(clang::QualType qual_type) {
+  if (IsVaListType(qual_type)) {
+    computed_expr_type_ = ComputedExprType::FreshValue;
+    return "VaList::default()";
+  }
+
   if (qual_type->isPointerType()) {
     if (qual_type->getPointeeType()->isFunctionType()) {
       return GetFunctionPointerDefaultAsString(qual_type);

cpp2rust/converter/converter_lib.cpp

@@ -600,24 +600,24 @@ bool IsRedundantCopyInConversion(clang::ASTContext &ctx,
   return parent && parent->getConstructor()->isConvertingConstructor(false);
 }
 
-// va_list is implemented as __va_list_tag[1] and decays to __va_list_tag *.
-// That's because va_list must have pointer semantics, but still be passed as
-// value by user code.
-bool IsVaListType(clang::ASTContext &ctx, clang::QualType type) {
-  auto canonical = type.getCanonicalType();
-  auto va_list = ctx.getBuiltinVaListType().getCanonicalType();
-
-  // Direct match: va_list itself
-  if (canonical == va_list) {
-    return true;
-  }
-
-  // Decayed match: __va_list_tag[1] decays to __va_list_tag *
-  if (auto *arr = clang::dyn_cast<clang::ConstantArrayType>(va_list)) {
-    return canonical ==
-           ctx.getPointerType(arr->getElementType()).getCanonicalType();
+bool IsVaListType(clang::QualType type) {
+  for (auto t = type; !t.isNull();) {
+    if (auto *adjusted = t->getAs<clang::AdjustedType>()) {
+      // Possibly decayed va_list
+      t = adjusted->getOriginalType();
+      continue;
+    } else if (auto *typedef_type = t->getAs<clang::TypedefType>()) {
+      // Typedef'ed va_list
+      if (auto decl = typedef_type->getDecl()) {
+        if (decl->getName().contains("va_list")) {
+          return true;
+        }
+        t = decl->getUnderlyingType();
+        continue;
+      }
+    }
+    break;
   }
-
   return false;
 }
 

cpp2rust/converter/converter_lib.h

@@ -142,7 +142,7 @@ std::string GetClassName(clang::QualType type);
 bool IsRedundantCopyInConversion(clang::ASTContext &ctx,
                                  const clang::CXXConstructExpr *expr);
 
-bool IsVaListType(clang::ASTContext &ctx, clang::QualType type);
+bool IsVaListType(clang::QualType type);
 
 bool IsBuiltinVaStart(const clang::CallExpr *expr);
 

cpp2rust/converter/models/converter_refcount.cpp

@@ -133,6 +133,12 @@ std::string ConverterRefCount::BoxValue(std::string &&str) const {
 }
 
 bool ConverterRefCount::Convert(clang::QualType qual_type) {
+  // Detect va_list before desugaring strips the typedef.
+  if (IsVaListType(qual_type)) {
+    StrCat(BoxType("VaList"));
+    return false;
+  }
+
   if (!Mapper::Contains(qual_type))
     qual_type = qual_type.getUnqualifiedType().getDesugaredType(ctx_);
 
@@ -172,7 +178,7 @@ bool ConverterRefCount::VisitPointerType(clang::PointerType *type) {
     return false;
   }
 
-  if (IsVaListType(ctx_, clang::QualType(type, 0))) {
+  if (IsVaListType(clang::QualType(type, 0))) {
     StrCat("VaList");
     return false;
   }
@@ -933,7 +939,7 @@ bool ConverterRefCount::VisitImplicitCastExpr(clang::ImplicitCastExpr *expr) {
   }
 
   if (expr->getCastKind() == clang::CastKind::CK_ArrayToPointerDecay) {
-    if (IsVaListType(ctx_, sub_expr->getType())) {
+    if (IsVaListType(sub_expr->getType())) {
       Convert(sub_expr);
       return false;
     }
@@ -1408,6 +1414,10 @@ bool ConverterRefCount::VisitCXXDefaultArgExpr(clang::CXXDefaultArgExpr *expr) {
 }
 
 std::string ConverterRefCount::GetDefaultAsString(clang::QualType qual_type) {
+  if (IsVaListType(qual_type)) {
+    return BoxValue("VaList::default()");
+  }
+
   std::string ret;
   if (qual_type->isPointerType()) {
     auto pointee_type = qual_type->getPointeeType();