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After the previous commit, this commit updates the value_struct_elt function to take an array_view rather than a NULL terminated array of values. The requirement for a NULL terminated array of values actually stems from typecmp, so the change from an array to array_view needs to be propagated through to this function. While making this change I noticed that this fixes another bug, in value_x_binop and value_x_unop GDB creates an array of values which doesn't have a NULL at the end. An array_view of this array is passed to value_user_defined_op, which then unpacks the array_view and passed the raw array to value_struct_elt, but only if the language is not C++. As value_x_binop and value_x_unop can only request member functions with the names of C++ operators, then most of the time, assuming the inferior is not a C++ program, then GDB will not find a matching member function with the call to value_struct_elt, and so typecmp will never be called, and so, GDB will avoid undefined behaviour. However, it is worth remembering that, when GDB's language is set to "auto", the current language is selected based on the language of the current compilation unit. As C++ programs usually link against libc, which is written in C, then, if the inferior is stopped in libc GDB will set the language to C. And so, it is possible that we will end up using value_struct_elt to try and lookup, and match, a C++ operator. If this occurs then GDB will experience undefined behaviour. I have extended the test added in the previous commit to also cover this case. Finally, this commit changes the API from passing around a pointer to an array to passing around a pointer to an array_view. The reason for this is that we need to be able to distinguish between the cases where we call value_struct_elt with no arguments, i.e. we are looking up a struct member, but we either don't have the arguments we want to pass yet, or we don't expect there to be any need for GDB to use the argument types to resolve any overloading; and the second case where we call value_struct_elt looking for a function that takes no arguments, that is, the argument list is empty. NOTE: While writing this I realise that if we pass an array_view at all then it will always have at least one item in it, the `this' pointer for the object we are planning to call the method on. So we could, I guess, pass an empty array_view to indicate the case where we don't know anything about the arguments, and when the array_view is length 1 or more, it means we do have the arguments. However, though we could do this, I don't think this would be better, the length 0 vs length 1 difference seems a little too subtle, I think that there's a better solution... I think a better solution would be to wrap the array_view in a gdb::optional, this would make the whole, do we have an array view or not question explicit. I haven't done this as part of this commit as making that change is much more extensive, every user of value_struct_elt will need to be updated, and as this commit already contains a bug fix, I wanted to keep the large refactoring in a separate commit, so, check out the next commit for the use of gdb::optional. gdb/ChangeLog: PR gdb/27994 * eval.c (structop_base_operation::evaluate_funcall): Pass array_view instead of array to value_struct_elt. * valarith.c (value_user_defined_op): Likewise. * valops.c (typecmp): Change parameter type from array pointer to array_view. Update header comment, and update body accordingly. (search_struct_method): Likewise. (value_struct_elt): Likewise. * value.h (value_struct_elt): Update declaration. gdb/testsuite/ChangeLog: PR gdb/27994 * gdb.cp/method-call-in-c.cc (struct foo_type): Add operator+=, change initial value of var member variable. (main): Make use of foo_type's operator+=. * gdb.cp/method-call-in-c.exp: Test use of operator+=.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.