Merge "Allow extending vtables"

vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp

@@ -246,18 +246,13 @@ bool AbiDiffHelper::CompareVTables(
       old_record->GetVTableLayout().GetVTableComponents();
   const std::vector<VTableComponentIR> &new_components =
       new_record->GetVTableLayout().GetVTableComponents();
-  if (old_components.size() > new_components.size()) {
+  if (old_components.size() != new_components.size()) {
-    // Something in the vtable got deleted.
     return false;
   }
-  uint32_t i = 0;
+  for (size_t i = 0; i < old_components.size(); i++) {
-  while (i < old_components.size()) {
+    if (!CompareVTableComponents(old_components[i], new_components[i])) {
-    auto &old_element = old_components.at(i);
-    auto &new_element = new_components.at(i);
-    if (!CompareVTableComponents(old_element, new_element)) {
       return false;
     }
-    i++;
   }
   return true;
 }

vndk/tools/header-checker/src/repr/ir_diff_representation.cpp

@@ -17,6 +17,99 @@
 namespace header_checker {
 namespace repr {
 
+static inline bool IsVOffset(VTableComponentIR::Kind kind) {
+  return kind == VTableComponentIR::VBaseOffset ||
+         kind == VTableComponentIR::VCallOffset;
+}
+
+static inline bool IsFunctionPointer(VTableComponentIR::Kind kind) {
+  return kind == VTableComponentIR::FunctionPointer ||
+         kind == VTableComponentIR::CompleteDtorPointer ||
+         kind == VTableComponentIR::DeletingDtorPointer;
+}
+
+// A Vtable consists of one or more sub-vtables. Each sub-vtable is a sequence
+// of components in the following order:
+//   Zero or more VCallOffset or VBaseOffset.
+//   One OffsetToTop.
+//   One RTTI.
+//   Zero or more FunctionPointer, CompleteDtorPointer, or DeletingDtorPointer.
+//
+// An object's vtable pointer points to the next component of the RTTI
+// component. Hence, new components can be appended or prepended to sub-vtables
+// without breaking compatibility.
+bool VTableLayoutDiffIR::IsExtended() const {
+  const std::vector<VTableComponentIR> &old_components =
+      old_layout_.GetVTableComponents();
+  const std::vector<VTableComponentIR> &new_components =
+      new_layout_.GetVTableComponents();
+  const auto old_end = old_components.end();
+  const auto new_end = new_components.end();
+  auto old_it = old_components.begin();
+  auto new_it = new_components.begin();
+  bool is_extended = false;
+  while (old_it != old_end) {
+    const auto old_begin = old_it;
+    const auto new_begin = new_it;
+    // Iterate VCallOffset and VBaseOffset.
+    while (old_it != old_end && IsVOffset(old_it->GetKind())) {
+      old_it++;
+    }
+    while (new_it != new_end && IsVOffset(new_it->GetKind())) {
+      new_it++;
+    }
+    // Compare VCallOffset and VBaseOffset.
+    auto old_back_it = old_it;
+    auto new_back_it = new_it;
+    while (old_back_it != old_begin) {
+      if (new_back_it == new_begin) {
+        return false;
+      }
+      old_back_it--;
+      new_back_it--;
+      if (old_back_it->GetKind() != new_back_it->GetKind()) {
+        return false;
+      }
+    }
+    // The new sub-vtable has additional VOffsets at the beginning.
+    if (new_back_it != new_begin) {
+      is_extended = true;
+    }
+    // Compare OffsetToTop.
+    if (old_it == old_end || new_it == new_end ||
+        old_it->GetKind() != VTableComponentIR::OffsetToTop ||
+        new_it->GetKind() != VTableComponentIR::OffsetToTop) {
+      return false;
+    }
+    old_it++;
+    new_it++;
+    // Compare RTTI.
+    if (old_it == old_end || new_it == new_end ||
+        old_it->GetKind() != VTableComponentIR::RTTI ||
+        new_it->GetKind() != VTableComponentIR::RTTI ||
+        old_it->GetName() != new_it->GetName()) {
+      return false;
+    }
+    old_it++;
+    new_it++;
+    // Compare function pointers.
+    while (old_it != old_end && IsFunctionPointer(old_it->GetKind())) {
+      if (new_it == new_end || old_it->GetKind() != new_it->GetKind() ||
+          old_it->GetName() != new_it->GetName()) {
+        return false;
+      }
+      old_it++;
+      new_it++;
+    }
+    // The new sub-vtable has additional function pointers at the end.
+    while (new_it != new_end && IsFunctionPointer(new_it->GetKind())) {
+      is_extended = true;
+      new_it++;
+    }
+  }
+  return new_it == new_end ? is_extended : false;
+}
+
 bool RecordTypeDiffIR::IsExtended() const {
   bool is_extended = false;
   if (type_diff_ != nullptr) {
@@ -43,8 +136,10 @@ bool RecordTypeDiffIR::IsExtended() const {
     return false;
   }
   if (vtable_diffs_ != nullptr) {
-    // TODO(b/248418092): Compare vtables.
+    if (!vtable_diffs_->IsExtended()) {
-    return false;
+      return false;
+    }
+    is_extended = true;
   }
   // This function skips comparing the access specifiers of field_diffs_
   // because AbiDiffHelper::CompareCommonRecordFields does not report

vndk/tools/header-checker/src/repr/ir_diff_representation.h

@@ -102,6 +102,8 @@ class VTableLayoutDiffIR {
     return new_layout_;
   }
 
+  bool IsExtended() const;
+
  protected:
   const VTableLayoutIR &old_layout_;
   const VTableLayoutIR &new_layout_;

vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h

@@ -11,4 +11,24 @@ struct Struct2 {
   } member;
 };
 
-Struct1 &PassByReference(Struct1 &, Struct2 &);
+struct Vtable1 {
+  int member_1;
+
+  virtual ~Vtable1();
+  virtual void function_1() = 0;
+};
+
+struct Vtable2 {
+  int member_2;
+
+  virtual void function_2() = 0;
+};
+
+struct Vtable3 : virtual public Vtable1, virtual public Vtable2 {
+  int member_3;
+
+  virtual ~Vtable3();
+  virtual void function_3();
+};
+
+Vtable3 &PassByReference(Struct1 &, Struct2 &);

vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h

@@ -14,4 +14,31 @@ struct Struct2 {
   } member;
 };
 
-Struct1 &PassByReference(Struct1 &, Struct2 &);
+struct Vtable1 {
+  int member_1;
+  int added_member_1;
+
+  virtual ~Vtable1();
+  virtual void function_1() = 0;
+  virtual void added_function_1() = 0;
+};
+
+struct Vtable2 {
+  int member_2;
+  int added_member_2;
+
+  virtual void function_2();
+  virtual void added_function_2() = 0;
+  virtual ~Vtable2();
+};
+
+struct Vtable3 : virtual public Vtable1, virtual public Vtable2 {
+  int member_3;
+  int added_member_3;
+
+  virtual ~Vtable3();
+  virtual void function_3();
+  virtual void added_function_3();
+};
+
+Vtable3 &PassByReference(Struct1 &, Struct2 &);

vndk/tools/header-checker/tests/reference_dumps/arm64/liballowed_struct_extensions.so.lsdump

@@ -30,6 +30,12 @@
    "referenced_type" : "_ZTIs",
    "self_type" : "_ZTIs",
    "size" : 2
+  },
+  {
+   "linker_set_key" : "_ZTIv",
+   "name" : "void",
+   "referenced_type" : "_ZTIv",
+   "self_type" : "_ZTIv"
   }
  ],
  "elf_functions" :
@@ -55,7 +61,7 @@
      "referenced_type" : "_ZTIR7Struct2"
     }
    ],
-   "return_type" : "_ZTIR7Struct1",
+   "return_type" : "_ZTIR7Vtable3",
    "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h"
   }
  ],
@@ -79,9 +85,47 @@
    "self_type" : "_ZTIR7Struct2",
    "size" : 8,
    "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIR7Vtable3",
+   "name" : "Vtable3 &",
+   "referenced_type" : "_ZTI7Vtable3",
+   "self_type" : "_ZTIR7Vtable3",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h"
+  }
+ ],
+ "pointer_types" :
+ [
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP7Vtable1",
+   "name" : "Vtable1 *",
+   "referenced_type" : "_ZTI7Vtable1",
+   "self_type" : "_ZTIP7Vtable1",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP7Vtable2",
+   "name" : "Vtable2 *",
+   "referenced_type" : "_ZTI7Vtable2",
+   "self_type" : "_ZTIP7Vtable2",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP7Vtable3",
+   "name" : "Vtable3 *",
+   "referenced_type" : "_ZTI7Vtable3",
+   "self_type" : "_ZTIP7Vtable3",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h"
   }
  ],
- "pointer_types" : [],
  "qualified_types" : [],
  "record_types" :
  [
@@ -132,6 +176,233 @@
    "size" : 8,
    "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h"
   },
+  {
+   "alignment" : 8,
+   "fields" :
+   [
+    {
+     "field_name" : "member_1",
+     "field_offset" : 64,
+     "referenced_type" : "_ZTIi"
+    },
+    {
+     "field_name" : "added_member_1",
+     "field_offset" : 96,
+     "referenced_type" : "_ZTIi"
+    }
+   ],
+   "linker_set_key" : "_ZTI7Vtable1",
+   "name" : "Vtable1",
+   "referenced_type" : "_ZTI7Vtable1",
+   "self_type" : "_ZTI7Vtable1",
+   "size" : 16,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h",
+   "vtable_components" :
+   [
+    {
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable1"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable1D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable1D0Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable110function_1Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable116added_function_1Ev"
+    }
+   ]
+  },
+  {
+   "alignment" : 8,
+   "fields" :
+   [
+    {
+     "field_name" : "member_2",
+     "field_offset" : 64,
+     "referenced_type" : "_ZTIi"
+    },
+    {
+     "field_name" : "added_member_2",
+     "field_offset" : 96,
+     "referenced_type" : "_ZTIi"
+    }
+   ],
+   "linker_set_key" : "_ZTI7Vtable2",
+   "name" : "Vtable2",
+   "referenced_type" : "_ZTI7Vtable2",
+   "self_type" : "_ZTI7Vtable2",
+   "size" : 16,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h",
+   "vtable_components" :
+   [
+    {
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable2"
+    },
+    {
+     "mangled_component_name" : "_ZN7Vtable210function_2Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable216added_function_2Ev"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable2D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable2D0Ev"
+    }
+   ]
+  },
+  {
+   "alignment" : 8,
+   "base_specifiers" :
+   [
+    {
+     "is_virtual" : true,
+     "referenced_type" : "_ZTI7Vtable1"
+    },
+    {
+     "is_virtual" : true,
+     "referenced_type" : "_ZTI7Vtable2"
+    }
+   ],
+   "fields" :
+   [
+    {
+     "field_name" : "member_3",
+     "field_offset" : 64,
+     "referenced_type" : "_ZTIi"
+    },
+    {
+     "field_name" : "added_member_3",
+     "field_offset" : 96,
+     "referenced_type" : "_ZTIi"
+    }
+   ],
+   "linker_set_key" : "_ZTI7Vtable3",
+   "name" : "Vtable3",
+   "referenced_type" : "_ZTI7Vtable3",
+   "self_type" : "_ZTI7Vtable3",
+   "size" : 48,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/extensions.h",
+   "vtable_components" :
+   [
+    {
+     "component_value" : 32,
+     "kind" : "vbase_offset"
+    },
+    {
+     "component_value" : 16,
+     "kind" : "vbase_offset"
+    },
+    {
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable3"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable3D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable3D0Ev"
+    },
+    {
+     "mangled_component_name" : "_ZN7Vtable310function_3Ev"
+    },
+    {
+     "mangled_component_name" : "_ZN7Vtable316added_function_3Ev"
+    },
+    {
+     "kind" : "vcall_offset"
+    },
+    {
+     "kind" : "vcall_offset"
+    },
+    {
+     "component_value" : -16,
+     "kind" : "vcall_offset"
+    },
+    {
+     "component_value" : -16,
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable3"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZTv0_n24_N7Vtable3D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZTv0_n24_N7Vtable3D0Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable110function_1Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable116added_function_1Ev"
+    },
+    {
+     "component_value" : -32,
+     "kind" : "vcall_offset"
+    },
+    {
+     "kind" : "vcall_offset"
+    },
+    {
+     "kind" : "vcall_offset"
+    },
+    {
+     "component_value" : -32,
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable3"
+    },
+    {
+     "mangled_component_name" : "_ZN7Vtable210function_2Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable216added_function_2Ev"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZTv0_n40_N7Vtable3D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZTv0_n40_N7Vtable3D0Ev"
+    }
+   ]
+  },
   {
    "alignment" : 4,
    "fields" :

vndk/tools/header-checker/tests/reference_dumps/arm64/libstruct_extensions.so.lsdump

@@ -19,6 +19,12 @@
    "referenced_type" : "_ZTIs",
    "self_type" : "_ZTIs",
    "size" : 2
+  },
+  {
+   "linker_set_key" : "_ZTIv",
+   "name" : "void",
+   "referenced_type" : "_ZTIv",
+   "self_type" : "_ZTIv"
   }
  ],
  "elf_functions" :
@@ -44,7 +50,7 @@
      "referenced_type" : "_ZTIR7Struct2"
     }
    ],
-   "return_type" : "_ZTIR7Struct1",
+   "return_type" : "_ZTIR7Vtable3",
    "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h"
   }
  ],
@@ -68,9 +74,47 @@
    "self_type" : "_ZTIR7Struct2",
    "size" : 8,
    "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIR7Vtable3",
+   "name" : "Vtable3 &",
+   "referenced_type" : "_ZTI7Vtable3",
+   "self_type" : "_ZTIR7Vtable3",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h"
+  }
+ ],
+ "pointer_types" :
+ [
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP7Vtable1",
+   "name" : "Vtable1 *",
+   "referenced_type" : "_ZTI7Vtable1",
+   "self_type" : "_ZTIP7Vtable1",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP7Vtable2",
+   "name" : "Vtable2 *",
+   "referenced_type" : "_ZTI7Vtable2",
+   "self_type" : "_ZTIP7Vtable2",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP7Vtable3",
+   "name" : "Vtable3 *",
+   "referenced_type" : "_ZTI7Vtable3",
+   "self_type" : "_ZTIP7Vtable3",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h"
   }
  ],
- "pointer_types" : [],
  "qualified_types" : [],
  "record_types" :
  [
@@ -114,6 +158,175 @@
    "size" : 4,
    "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h"
   },
+  {
+   "alignment" : 8,
+   "fields" :
+   [
+    {
+     "field_name" : "member_1",
+     "field_offset" : 64,
+     "referenced_type" : "_ZTIi"
+    }
+   ],
+   "linker_set_key" : "_ZTI7Vtable1",
+   "name" : "Vtable1",
+   "referenced_type" : "_ZTI7Vtable1",
+   "self_type" : "_ZTI7Vtable1",
+   "size" : 16,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h",
+   "vtable_components" :
+   [
+    {
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable1"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable1D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable1D0Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable110function_1Ev"
+    }
+   ]
+  },
+  {
+   "alignment" : 8,
+   "fields" :
+   [
+    {
+     "field_name" : "member_2",
+     "field_offset" : 64,
+     "referenced_type" : "_ZTIi"
+    }
+   ],
+   "linker_set_key" : "_ZTI7Vtable2",
+   "name" : "Vtable2",
+   "referenced_type" : "_ZTI7Vtable2",
+   "self_type" : "_ZTI7Vtable2",
+   "size" : 16,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h",
+   "vtable_components" :
+   [
+    {
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable2"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable210function_2Ev"
+    }
+   ]
+  },
+  {
+   "alignment" : 8,
+   "base_specifiers" :
+   [
+    {
+     "is_virtual" : true,
+     "referenced_type" : "_ZTI7Vtable1"
+    },
+    {
+     "is_virtual" : true,
+     "referenced_type" : "_ZTI7Vtable2"
+    }
+   ],
+   "fields" :
+   [
+    {
+     "field_name" : "member_3",
+     "field_offset" : 64,
+     "referenced_type" : "_ZTIi"
+    }
+   ],
+   "linker_set_key" : "_ZTI7Vtable3",
+   "name" : "Vtable3",
+   "referenced_type" : "_ZTI7Vtable3",
+   "self_type" : "_ZTI7Vtable3",
+   "size" : 48,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/struct_extensions/include/base.h",
+   "vtable_components" :
+   [
+    {
+     "component_value" : 32,
+     "kind" : "vbase_offset"
+    },
+    {
+     "component_value" : 16,
+     "kind" : "vbase_offset"
+    },
+    {
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable3"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable3D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZN7Vtable3D0Ev"
+    },
+    {
+     "mangled_component_name" : "_ZN7Vtable310function_3Ev"
+    },
+    {
+     "kind" : "vcall_offset"
+    },
+    {
+     "component_value" : -16,
+     "kind" : "vcall_offset"
+    },
+    {
+     "component_value" : -16,
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable3"
+    },
+    {
+     "kind" : "complete_dtor_pointer",
+     "mangled_component_name" : "_ZTv0_n24_N7Vtable3D1Ev"
+    },
+    {
+     "kind" : "deleting_dtor_pointer",
+     "mangled_component_name" : "_ZTv0_n24_N7Vtable3D0Ev"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable110function_1Ev"
+    },
+    {
+     "kind" : "vcall_offset"
+    },
+    {
+     "component_value" : -32,
+     "kind" : "offset_to_top"
+    },
+    {
+     "kind" : "rtti",
+     "mangled_component_name" : "_ZTI7Vtable3"
+    },
+    {
+     "is_pure" : true,
+     "mangled_component_name" : "_ZN7Vtable210function_2Ev"
+    }
+   ]
+  },
   {
    "access" : "protected",
    "alignment" : 4,