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lalr1.cc: modern C++ no longer needs an assignment for symbols

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Reported by Frank Heckenbach.
http://lists.gnu.org/archive/html/bug-bison/2018-03/msg00002.html

Actually the assignment operator should never be needed: the C++98
requirements for vector::push_back is CopyInsertable, which does not require
an assignment operator.  However, libstdc++ shipped with GCC up to (and
including) 6 uses the assignment operator (which affects Clang on top of
libstdc++, but also ICC).  So let's keep it for legacy C++.

See https://gcc.godbolt.org/z/q0XXmC.

* data/lalr1.cc (stack_symbol_type::operator=): Remove.
* data/c++.m4 (basic_symbol::operator=): Ditto.
* tests/c++.at (C++ Variant-based Symbols Unit Tests): Adjust.
This commit is contained in:
Akim Demaille
2018-09-10 20:01:48 +02:00
parent f19ecae3b2
commit 09bc1b99c9
3 changed files with 9 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
data/c++.m4
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@@ -272,8 +272,10 @@ m4_define([b4_symbol_type_declare],
location_type location;])[ location_type location;])[
private: private:
#if defined __cplusplus && __cplusplus < 201103L
/// Assignment operator. /// Assignment operator.
basic_symbol& operator= (const basic_symbol& other); basic_symbol& operator= (const basic_symbol& other);
#endif
}; };
/// Type access provider for token (enum) based symbols. /// Type access provider for token (enum) based symbols.

6
data/lalr1.cc
View File

@@ -326,8 +326,10 @@ b4_location_define])])[
stack_symbol_type (YY_RVREF (stack_symbol_type) that); stack_symbol_type (YY_RVREF (stack_symbol_type) that);
/// Steal the contents from \a sym to build this. /// Steal the contents from \a sym to build this.
stack_symbol_type (state_type s, YY_MOVE_REF (symbol_type) sym); stack_symbol_type (state_type s, YY_MOVE_REF (symbol_type) sym);
/// Assignment, needed by push_back. #if defined __cplusplus && __cplusplus < 201103L
/// Assignment, needed by push_back by some old implementations.
stack_symbol_type& operator= (YY_MOVE_REF (stack_symbol_type) that); stack_symbol_type& operator= (YY_MOVE_REF (stack_symbol_type) that);
#endif
}; };
/// Stack type. /// Stack type.
@@ -608,6 +610,7 @@ m4_if(b4_prefix, [yy], [],
that.type = empty_symbol; that.type = empty_symbol;
} }
#if defined __cplusplus && __cplusplus < 201103L
]b4_parser_class_name[::stack_symbol_type& ]b4_parser_class_name[::stack_symbol_type&
]b4_parser_class_name[::stack_symbol_type::operator= (YY_MOVE_REF (stack_symbol_type) that) ]b4_parser_class_name[::stack_symbol_type::operator= (YY_MOVE_REF (stack_symbol_type) that)
{ {
@@ -618,6 +621,7 @@ m4_if(b4_prefix, [yy], [],
location = YY_MOVE (that.location);])[ location = YY_MOVE (that.location);])[
return *this; return *this;
} }
#endif
template <typename Base> template <typename Base>
void void

4
tests/c++.at
View File

@@ -166,12 +166,12 @@ int main()
for (int i = 0; i < 100; ++i) for (int i = 0; i < 100; ++i)
{ {
#if defined __cplusplus && 201103L <= __cplusplus #if defined __cplusplus && 201103L <= __cplusplus
auto ss = parser::stack_symbol_type(1, parser::make_INT(123)); st.push(parser::stack_symbol_type{1, parser::make_INT(123)});
#else #else
parser::symbol_type s = parser::make_INT(123); parser::symbol_type s = parser::make_INT(123);
parser::stack_symbol_type ss(1, s); parser::stack_symbol_type ss(1, s);
#endif
st.push(ss); st.push(ss);
#endif
} }
} }
} }