[cfe-users] Implicit or explicit public inheritance in the AST

[Csaba Raduly via cfe-users]

Hi all,

If I run `clang++ -std=c++17 -Xclang -ast-dump` on the following code:

struct B {};

struct D1 : B {};

struct D2 : public B {};

the output is

|-CXXRecordDecl 0x8000bdd48 <kg.cpp:1:1, col:11> col:8 referenced struct B
definition
| |-DefinitionData pass_in_registers empty aggregate standard_layout
trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor
can_const_default_init
| | |-DefaultConstructor exists trivial constexpr needs_implicit
defaulted_is_constexpr
| | |-CopyConstructor simple trivial has_const_param needs_implicit
implicit_has_const_param
| | |-MoveConstructor exists simple trivial needs_implicit
| | |-CopyAssignment trivial has_const_param needs_implicit
implicit_has_const_param
| | |-MoveAssignment exists simple trivial needs_implicit
| | `-Destructor simple irrelevant trivial needs_implicit
| `-CXXRecordDecl 0x8000bde58 <col:1, col:8> col:8 implicit struct B
|-CXXRecordDecl 0x8000bdef8 <line:3:1, col:16> col:8 struct D1 definition
| |-DefinitionData pass_in_registers empty aggregate standard_layout
trivially_copyable trivial literal has_constexpr_non_copy_move_ctor
can_const_default_init
| | |-DefaultConstructor exists trivial constexpr needs_implicit
defaulted_is_constexpr
| | |-CopyConstructor simple trivial has_const_param needs_implicit
implicit_has_const_param
| | |-MoveConstructor exists simple trivial needs_implicit
| | |-CopyAssignment trivial has_const_param needs_implicit
implicit_has_const_param
| | |-MoveAssignment exists simple trivial needs_implicit
| | `-Destructor simple irrelevant trivial needs_implicit
| |-public 'B'
| `-CXXRecordDecl 0x80015c878 <col:1, col:8> col:8 implicit struct D1
`-CXXRecordDecl 0x80015c918 <line:5:1, col:23> col:8 struct D2 definition
  |-DefinitionData pass_in_registers empty aggregate standard_layout
trivially_copyable trivial literal has_constexpr_non_copy_move_ctor
can_const_default_init
  | |-DefaultConstructor exists trivial constexpr needs_implicit
defaulted_is_constexpr
  | |-CopyConstructor simple trivial has_const_param needs_implicit
implicit_has_const_param
  | |-MoveConstructor exists simple trivial needs_implicit
  | |-CopyAssignment trivial has_const_param needs_implicit
implicit_has_const_param
  | |-MoveAssignment exists simple trivial needs_implicit
  | `-Destructor simple irrelevant trivial needs_implicit
  |-public 'B'
  `-CXXRecordDecl 0x80015ca68 <col:1, col:8> col:8 implicit struct D2
I can see no difference between the CXXRecordDecl for D1 and D2. Is there a
way to tell, when visiting the AST, whether the inheritance of the derived
class was specified implicitly or explicitly? (Hopefully yes, just not
visible in the output of ast-dump).


Csaba
Sent from my 12-core Windows machine, using Gmail.
-- 
You can get very substantial performance improvements
by not doing the right thing. - Scott Meyers, An Effective C++11/14 Sampler
So if you're looking for a completely portable, 100% standards-conformant
way
to get the wrong information: this is what you want. - Scott Meyers
(C++TDaWYK)
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