Translate anonymous structs (#33)

Author: lucic71

cpp2rust/converter/converter_lib.cpp

@@ -12,6 +12,7 @@
 #include <array>
 #include <cctype>
 #include <filesystem>
+#include <format>
 #include <unordered_set>
 
 #include "converter/lex.h"
@@ -296,6 +297,25 @@ unsigned GetArraySize(clang::QualType array_type) {
   return constant_array_ty->getSize().getZExtValue();
 }
 
+unsigned GetAnonIndex(const clang::NamedDecl *decl) {
+  if (auto *parent =
+          clang::dyn_cast<clang::RecordDecl>(decl->getDeclContext())) {
+    unsigned counter = 0;
+    for (auto *d : parent->decls()) {
+      if (d == decl) {
+        return counter;
+      }
+      auto *named = clang::dyn_cast<clang::NamedDecl>(d);
+      if (named && named->getKind() == decl->getKind() &&
+          named->getName().empty()) {
+        counter++;
+      }
+    }
+    return counter;
+  }
+  return 0;
+}
+
 std::string GetID(const clang::Decl *decl) {
   assert(decl);
   const auto file_name = GetFileName(decl);
@@ -317,6 +337,17 @@ std::string GetNamedDeclAsString(const clang::NamedDecl *decl) {
   auto name = decl->getDeclName().isIdentifier() ? decl->getName().str()
                                                  : decl->getNameAsString();
 
+  // Anonymous record field
+  if (auto *field = clang::dyn_cast<clang::FieldDecl>(decl);
+      field && name.empty()) {
+    const clang::NamedDecl *target = field;
+    if (auto *record = field->getType()->getAsRecordDecl();
+        record && !record->getIdentifier()) {
+      target = record;
+    }
+    return std::format("anon_{}", GetAnonIndex(target));
+  }
+
   if (auto *fn = clang::dyn_cast<clang::FunctionDecl>(decl)) {
     if (!clang::isa<clang::CXXMethodDecl>(fn)) {
       auto mangled =

cpp2rust/converter/converter_lib.h

@@ -82,6 +82,8 @@ std::string GetID(const clang::Decl *decl);
 
 std::string GetNamedDeclAsString(const clang::NamedDecl *decl);
 
+unsigned GetAnonIndex(const clang::NamedDecl *decl);
+
 const char *AccessSpecifierAsString(clang::AccessSpecifier spec);
 
 template <class T> llvm::SmallString<16> GetNumAsString(const T &num) {

cpp2rust/converter/mapper.cpp

@@ -562,6 +562,18 @@ std::string normalizeTranslationRule(std::string rule) {
   return rule;
 }
 
+static std::string synthesizeAnonRecordName(const clang::RecordDecl *record) {
+  std::string parent_name;
+  if (auto *parent =
+          clang::dyn_cast<clang::RecordDecl>(record->getDeclContext())) {
+    parent_name = parent->getIdentifier()
+                      ? parent->getIdentifier()->getName().str()
+                      : synthesizeAnonRecordName(parent);
+    parent_name += '_';
+  }
+  return std::format("{}anon_{}", parent_name, GetAnonIndex(record));
+}
+
 } // namespace
 
 PushASTContext::PushASTContext(clang::ASTContext &ctx) : prev_(ctx_) {
@@ -724,6 +736,11 @@ std::string ToString(clang::QualType qual_type) {
 }
 
 std::string ToString(const clang::NamedDecl *decl) {
+  if (auto *record = clang::dyn_cast<clang::RecordDecl>(decl);
+      record && !record->getIdentifier()) {
+    return synthesizeAnonRecordName(record);
+  }
+
   std::string out;
   llvm::raw_string_ostream os(out);
 

cpp2rust/converter/models/converter_refcount.cpp

@@ -1519,6 +1519,7 @@ bool ConverterRefCount::VisitCXXConstructExpr(clang::CXXConstructExpr *expr) {
 
 bool ConverterRefCount::VisitImplicitValueInitExpr(
     clang::ImplicitValueInitExpr *expr) {
+  PushConversionKind push(*this, ConversionKind::Unboxed);
   if (auto arr_ty = clang::dyn_cast<clang::ArrayType>(
           expr->getType()->getCanonicalTypeInternal().getTypePtr())) {
     if (clang::isa<clang::ConstantArrayType>(arr_ty)) {

tests/lit/lit/formats/Cpp2RustTest.py

@@ -118,22 +118,23 @@ def fail(str, code = fail_code):
     if should_not_translate:
       return fail('expected translation-fail but cpp2rust succeeded')
 
-    expected_file = self.getExpectedFile(filepath, model, fname)
-    if not os.path.exists(expected_file) and not replace_expected:
-      return fail('no expected file')
+    if not should_not_compile:
+      expected_file = self.getExpectedFile(filepath, model, fname)
+      if not os.path.exists(expected_file) and not replace_expected:
+        return fail('no expected file')
 
-    if replace_expected:
-      self.updateExpected(generated, expected_file)
+      if replace_expected:
+        self.updateExpected(generated, expected_file)
 
-    with open(expected_file, 'r') as f:
-      expected = f.read()
+      with open(expected_file, 'r') as f:
+        expected = f.read()
 
-    if generated != expected:
-      diff = ''.join(difflib.unified_diff(
-        expected.splitlines(keepends=True),
-        generated.splitlines(keepends=True),
-        fromfile='expected', tofile='generated'))
-      return fail('different output\n' + diff)
+      if generated != expected:
+        diff = ''.join(difflib.unified_diff(
+          expected.splitlines(keepends=True),
+          generated.splitlines(keepends=True),
+          fromfile='expected', tofile='generated'))
+        return fail('different output\n' + diff)
 
     pkg_name = "test_" + re.sub(r'[^a-zA-Z0-9_]', '_', os.path.basename(tmp_dir))
 
@@ -163,7 +164,7 @@ def fail(str, code = fail_code):
     if should_not_compile:
       if returncode != 0:
         shutil.rmtree(tmp_dir, True)
-        return lit.Test.PASS, ''
+        return lit.Test.XFAIL, ''
       return fail('expected no-compile but compiled successfully')
     if returncode != 0:
       return fail('cargo failed\n' + err)

tests/unit/anonymous-struct.cpp

@@ -0,0 +1,74 @@
+#include <cassert>
+
+struct Outer {
+  struct Named {
+    int a;
+    int b;
+  } named;
+
+  struct {
+    int c;
+    int d;
+  } anonymous_named_0;
+
+  struct {
+    int g;
+    int h;
+  } anonymous_named_1;
+
+  struct {
+    int e;
+    int f;
+  };
+
+  struct {
+    int i;
+    struct {
+      int j;
+    } inner_named;
+    struct {
+      int k;
+    };
+  };
+};
+
+int main() {
+  Outer o = {};
+
+  o.named.a = 1;
+  o.named.b = 2;
+  o.anonymous_named_0.c = 3;
+  o.anonymous_named_0.d = 4;
+  o.anonymous_named_1.g = 5;
+  o.anonymous_named_1.h = 6;
+  o.e = 7;
+  o.f = 8;
+  o.i = 9;
+  o.inner_named.j = 10;
+  o.k = 11;
+
+  assert(o.named.a == 1);
+  assert(o.named.b == 2);
+  assert(o.anonymous_named_0.c == 3);
+  assert(o.anonymous_named_0.d == 4);
+  assert(o.anonymous_named_1.g == 5);
+  assert(o.anonymous_named_1.h == 6);
+  assert(o.e == 7);
+  assert(o.f == 8);
+  assert(o.i == 9);
+  assert(o.inner_named.j == 10);
+  assert(o.k == 11);
+
+  struct {
+    int x;
+    int z;
+  } s;
+
+  s.x = 1;
+  s.z = 2;
+
+  assert(s.x = 1);
+  assert(s.z = 2);
+
+  return 0;
+}

tests/unit/anonymous-struct_c.c

@@ -0,0 +1,74 @@
+#include <assert.h>
+
+struct Outer {
+  struct Named {
+    int a;
+    int b;
+  } named;
+
+  struct {
+    int c;
+    int d;
+  } anon0;
+
+  struct {
+    int g;
+    int h;
+  } anon1;
+
+  struct {
+    int e;
+    int f;
+  };
+
+  struct {
+    int i;
+    struct {
+      int j;
+    } inner_named;
+    struct {
+      int k;
+    };
+  };
+};
+
+int main(void) {
+  struct Outer o = {0};
+
+  o.named.a = 1;
+  o.named.b = 2;
+  o.anon0.c = 3;
+  o.anon0.d = 4;
+  o.anon1.g = 5;
+  o.anon1.h = 6;
+  o.e = 7;
+  o.f = 8;
+  o.i = 9;
+  o.inner_named.j = 10;
+  o.k = 11;
+
+  assert(o.named.a == 1);
+  assert(o.named.b == 2);
+  assert(o.anon0.c == 3);
+  assert(o.anon0.d == 4);
+  assert(o.anon1.g == 5);
+  assert(o.anon1.h == 6);
+  assert(o.e == 7);
+  assert(o.f == 8);
+  assert(o.i == 9);
+  assert(o.inner_named.j == 10);
+  assert(o.k == 11);
+
+  struct {
+    int x;
+    int z;
+  } s;
+
+  s.x = 1;
+  s.z = 2;
+
+  assert(s.x = 1);
+  assert(s.z = 2);
+
+  return 0;
+}