The forthcoming automove feature, to be properly checked, will require
that we can rely on the value of a moved-from string, which is not
something the C++ standard guarantees. So introduce our own wrapper.
Suggested by Frank Heckenbach.
https://lists.gnu.org/archive/html/bison-patches/2018-09/msg00111.html
* tests/c++.at (Variants): Introduce and use a new 'string' class.
The 'Variants' tests are well suited to check support for move, and in
particular for the forthcoming automove feature. But the tests were
written to show the best practice in C++98, using swap:
list "," item { std::swap ($$, $1); $$.push_back ($3); }
This cannot work with std::move. So, make this example simpler, based
on regular assignment instead of swap, which is a regression for
C++98 (as the new traces show), but will be an improvement for modern
C++ with automove.
* tests/c++.at (Variants): Stop using swap.
We don't generate a header file, so remove the 'require' code section.
Adjust expectations.
Several types of failures. First, unable to pass the file name
properly to the linker.
./synclines.at:416: $CC $CFLAGS $CPPFLAGS $LDFLAGS -o \"\\\"\" \"\\\"\".c $LIBS
stderr:
ld: cannot open output file "/"": No such file or directory
stdout:
Unable to save under such a file name.
./synclines.at:421: $CXX $CXXFLAGS $CPPFLAGS -c $LDFLAGS -o \"\\\"\" \"\\\"\".cc $LIBS
stderr:
error: can't open file "/"" for write
compilation aborted for "\"".cc (code 1)
Spurious output because of warning flags is failed to reject as an
error during configure:
./headers.at:343: $CXX $CXXFLAGS $CPPFLAGS $LDFLAGS c-only.o cxx-only.o -o c-and-cxx ||
exit 77
--- /dev/null 2018-09-18 21:21:37.745649000 +0000
+++ /home/travis/build/akimd/bison/tests/testsuite.dir/at-groups/222/stderr 2018-09-18 21:28:17.291919519 +0000
@@ -0,0 +1,7 @@
+icpc: command line warning #10006: ignoring unknown option '-Wcast-align'
+icpc: command line warning #10006: ignoring unknown option '-fparse-all-comments'
+icpc: command line warning #10006: ignoring unknown option '-Wdocumentation'
+icpc: command line warning #10006: ignoring unknown option '-Wnull-dereference'
+icpc: command line warning #10006: ignoring unknown option '-Wnoexcept'
+icpc: command line warning #10006: ignoring unknown option '-fno-color-diagnostics'
+icpc: command line warning #10006: ignoring unknown option '-Wno-keyword-macro'
stdout:
* tests/local.at (AT_SKIP_IF_CANNOT_LINK_C_AND_CXX): Also ignore
stderr, as with ICC we get
* tests/synclines.at (syncline escapes): Don't link the output.
The code was already using midrule only, never mid_rule. This is
simpler to remember, and matches a similar change we made from
look-ahead to lookahead.
* NEWS, doc/bison.texi, src/reader.c, src/scan-code.h, src/scan-code.l
* tests/actions.at, tests/c++.at, tests/existing.at: here.
We use both styles, let's stick to a single one. Autoconf uses the
prefix one, let's do the same.
* data/bison.m4, data/c++.m4, data/c-like.m4, data/lalr1.cc,
* data/variant.hh, data/yacc.c: Rename all the b4_*_ macros
as _b4_*.
On the CI, we had failures such as:
./c++.at:401: $PREPARSER ./list
stderr:
./list: error while loading shared libraries: libc++.so.1:
cannot open shared object file: No such file or directory
because we accepted `-std=c++ -stdlib=libc++` although libc++ is not
installed on the machine.
* m4/ax_check_compile_flag.m4 (AX_CHECK_COMPILE_FLAG): Rewrite as...
* m4/bison-check-compile-flag.m4 (BISON_CHECK_COMPILE_FLAG): this, so
that we use AC_LINK_IFELSE to check the compiler (and its std lib)
instead of AC_COMPILE_IFELSE.
The CI is littered with
# -*- compilation -*-
423. regression.at:907: testing Dancer %glr-parser ...
./regression.at:907: bison -fno-caret -o dancer.c dancer.y
./regression.at:907: $BISON_C_WORKS
stderr:
stdout:
./regression.at:907: $CC $CFLAGS $CPPFLAGS $LDFLAGS -o dancer dancer.c $LIBS
stderr:
icc: command line warning #10006: ignoring unknown option '-Wcast-align'
icc: command line warning #10006: ignoring unknown option '-fparse-all-comments'
icc: command line warning #10006: ignoring unknown option '-Wdocumentation'
icc: command line warning #10006: ignoring unknown option '-Wnull-dereference'
icc: command line warning #10006: ignoring unknown option '-Wbad-function-cast'
icc: command line warning #10006: ignoring unknown option '-fno-color-diagnostics'
icc: command line warning #10006: ignoring unknown option '-Wno-keyword-macro'
dancer.c(755): error #1628: function declared with "noreturn" does return
}
^
dancer.c(761): error #1628: function declared with "noreturn" does return
}
^
compilation aborted for dancer.c (code 2)
ICC sees that `longjmp(buf, 1);` does not return, it sees that
`abort();` does not either, but fails to see it for
`longjmp(buf, 1); abort();`
* data/glr.c (YYLONGJMP): Be even clearer on the fact this does not
return.
Putting them in the env is useless. We don't want to pass
`CPPFLAGS="$CPPFLAGS"` to configure, as it means "set it to nothing"
when $CPPFLAGS is not set, which is not what we want.
This correctly started to use libc++, but it is not installed on the
Ubuntu. We will see later if we can use it.
* .travis.yml: Define CONFIGUREFLAGS, and pass it to configure.
* build-aux/install-icc.sh: New.
* .travis.yml (icc): New.
Use -k to get as many errors as possible from the start.
* src/complain.c (warnings_types): Use a more precise type.
On the CI, we have this spurious failure with clang 3.9 with
-std=c++17:
In file included from list.y:23:
In file included from /usr/include/c++/4.8/iostream:39:
In file included from /usr/include/c++/4.8/ostream:38:
In file included from /usr/include/c++/4.8/ios:42:
In file included from /usr/include/c++/4.8/bits/ios_base.h:41:
In file included from /usr/include/c++/4.8/bits/locale_classes.h:40:
In file included from /usr/include/c++/4.8/string:52:
In file included from /usr/include/c++/4.8/bits/basic_string.h:2815:
In file included from /usr/include/c++/4.8/ext/string_conversions.h:43:
/usr/include/c++/4.8/cstdio:120:11: error: no member named 'gets' in the global namespace
using ::gets;
~~^
This shows that our test, based on gl_WARN_ADD, is a joke. We have to
really check for at least a bit of C++.
* m4/ax_check_compile_flag.m4, m4/bison-cxx-std.m4: New.
* configure.ac: Use them to make sure the compiler actually works.
In C++ pre C++11 it is standard practice to use 0 for the null pointer.
But GCC pre 8 -std=c++98 with -Wzero-as-null-pointer-constant warns about
this.
So disable -Wzero-as-null-pointer-constant when compiling C++ pre 11.
Let's do this in AT_DATA_SOURCE_PROLOGUE (which is pasted on top of
all the test grammar files). Unfortunately, that shifts all the
locations in the expected error messages, which would be too noisy.
Instead, let's introduce testsuite.h, which can vary in length, and
include it in AT_DATA_SOURCE_PROLOGUE.
* tests/testsuite.h: New.
Disable -Wzero-as-null-pointer-constant's warning with GCC pre 8,
C++ pre 11.
* tests/local.at (AT_DATA_SOURCE_PROLOGUE): Use it.
* tests/atlocal.in (CPPFLAGS): Find it.
* tests/local.mk: Ship it.
* data/c.m4 (YY_NULLPTR): Prefer ((void*)0) to 0 in C.
For some reasons, the checkout on travis may not have any tags, so
`git describe` fails, so bootstrap fails.
* .travis.yml: If git describe fails, install some tag.
This is much of course more efficient than in the matrix of the CI (or
on our own machines), but a bit more tedious.
* configure.ac (CXX03_CXXFLAGS, CXX11_CXXFLAGS, CXX14_CXXFLAGS)
(CXX17_CXXFLAGS, CXX2A_CXXFLAGS, STDCXX_FLAGS): New.
* tests/atlocal.in: Receive them.
* tests/local.at (AT_FOR_EACH_CXX): New.
* tests/c++.at: Use AT_FOR_EACH_CXX.
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.
Modern C++ (i.e., C++11 and later) introduced "move only" types: types such
as std::unique_ptr<T> that can never be duplicated. They must never be
copied (by assignments and constructors), they must be "moved". The
implementation of lalr1.cc used to copy symbols (including their semantic
values). This commit ensures that values are only moved in modern C++, yet
remain compatible with C++98/C++03.
Suggested by Frank Heckenbach, who provided a full implementation on
top of C++17's std::variant.
See http://lists.gnu.org/archive/html/bug-bison/2018-03/msg00002.html,
and https://lists.gnu.org/archive/html/bison-patches/2018-04/msg00002.html.
Symbols (terminal/non terminal) are handled by several functions that used
to take const-refs, which resulted eventually in a copy pushed on the stack.
With modern C++ (C++11 and later) the callers must use std::move, and the
callees must take their arguments as rvalue refs (foo&&). In order to avoid
duplicating these functions to support both legacy C++ and modern C++, let's
introduce macros (YY_MOVE, YY_RVREF, etc.) that rely on copy-semantics for
C++98/03, and move-semantics for modern C++.
That's easy for inner types, when the parser's functions pass arguments to
each other. Functions facing the user (make_NUMBER, make_STRING, etc.)
should support both rvalue-refs (for instance to support move-only types:
make_INT (std::make_unique<int> (1))), and lvalue-refs (so that we can pass
a variable: make_INT (my_int)). To avoid the multiplication of the
signatures (there is also the location), let's take the argument by value.
See:
https://lists.gnu.org/archive/html/bison-patches/2018-09/msg00024.html.
* data/c++.m4 (b4_cxx_portability): New.
(basic_symbol): In C++11, replace copy-ctors with move-ctors.
In C++11, replace copies with moves.
* data/lalr1.cc (stack_symbol_type, yypush_): Likewise.
Use YY_MOVE to avoid useless copies.
* data/variant.hh (variant): Support move-semantics.
(make_SYMBOL): In C++11, in order to support both read-only lvalues,
and rvalues, take the argument as a copy.
* data/stack.hh (yypush_): Use rvalue-refs in C++11.
* tests/c++.at: Use move semantics.
* tests/headers.at: Adjust to the new macros (YY_MOVE, etc.).
* configure.ac (CXX98_CXXFLAGS, CXX11_CXXFLAGS, CXX14_CXXFLAGS)
(CXX17_CXXFLAGS, ENABLE_CXX11): New.
* tests/atlocal.in: Receive them.
* examples/variant.yy: Don't define things in std.
* examples/variant-11.test, examples/variant-11.yy: New.
Check the support of move-only types.
* examples/README, examples/local.mk: Adjust.
This generates less code, which is nicer to read, but also takes less
chances with compilers such as G++ 4.8 that are too strict and check
"dead code" (templated code that is not instantiated).
* data/c++.m4 (b4_symbol_type_declare, b4_symbol_type_define): When
variants are used, don't generate code meant for non variants.
