On Sun, Feb 3, 2013 at 7:26 AM, Sudakshina Das <sudakshina1...@gmail.com> wrote:
> Hello,
>
> Now I am trying to convert the same pass into a dynamic plugin. Since
> I was having trouble doing so, I tried adding a simple dynamic plugin
> which would just dump the cfg using gimple_dump_cfg. But even in this
> simple plugin I faced the same problem, as explained below.
>
> When I build my plugin using ../install/bin/g++ it would not give any
> errors. But when I used gcc instead of g++, it gave the following
> error during runtime :
>
> cc1: error: cannot load plugin ./plugin.so
> ./plugin.so: undefined symbol: decl_assembler_name
> make: *** [test] Error 1
>
> However, this symbol decl_assembler_name (a function) and is not
> present anywhere in my plugin. It is declared in tree.c so and is not
> static, so I even tried including tree.h and declaring the function as
> extern.
>
> I don't know what else to do!!
You have to compile the plugin with a C++ compiler, as GCC 4.7 is now
built as a C++ program.
Richard.
> Sudakshina
>
>
>
>
> On Sat, Jan 26, 2013 at 1:16 AM, Sudakshina Das
> <sudakshina1...@gmail.com> wrote:
>>
>> On Fri, Jan 25, 2013 at 9:27 PM, Richard Biener
>> <richard.guent...@gmail.com> wrote:
>> > On Fri, Jan 25, 2013 at 3:57 PM, Sudakshina Das
>> > <sudakshina1...@gmail.com> wrote:
>> >> On Fri, Jan 25, 2013 at 8:02 PM, Richard Biener
>> >> <richard.guent...@gmail.com> wrote:
>> >>> On Fri, Jan 25, 2013 at 3:05 PM, Sudakshina Das
>> >>> <sudakshina1...@gmail.com> wrote:
>> >>>> On Fri, Jan 25, 2013 at 9:46 AM, Sudakshina Das
>> >>>> <sudakshina1...@gmail.com> wrote:
>> >>>>>
>> >>>>> On Thu, Jan 24, 2013 at 5:15 PM, Richard Biener
>> >>>>> <richard.guent...@gmail.com> wrote:
>> >>>>> >
>> >>>>> > On Thu, Jan 24, 2013 at 7:06 AM, Sudakshina Das
>> >>>>> > <sudakshina1...@gmail.com> wrote:
>> >>>>> > > Dear all,
>> >>>>> > >
>> >>>>> > > I am currently updating a pass that was made for gcc-4.6.*, so
>> >>>>> > > that it
>> >>>>> > > works for gcc.4.7.2.
>> >>>>> > >
>> >>>>> > > In the pass for gcc-4.6.*, a code fragment from
>> >>>>> > > tree-ssa-structalias.c
>> >>>>> > > was picked up and used.
>> >>>>> > > Given below is the fragment taken form create_function_info_for
>> >>>>> > > () .
>> >>>>> > > This fragment was used to create variable information for the
>> >>>>> > > function
>> >>>>> > > and it was picked up to perform a similar operation in the added
>> >>>>> > > pass
>> >>>>> > > as well.
>> >>>>> > >
>> >>>>> > > But in gcc-4.7.2 some changes are introduced in the fragment.
>> >>>>> > > The code
>> >>>>> > > given below shows the changes that have been introduced in
>> >>>>> > > create_function_info_for () of tree-ssa-structalias.c in
>> >>>>> > > gcc-4.7.2
>> >>>>> > > along with the original code in the comments.
>> >>>>> > >
>> >>>>> > > /* Add one representative for all further args. */
>> >>>>> > > if (is_varargs)
>> >>>>> > > {
>> >>>>> > > varinfo_t argvi;
>> >>>>> > > const char *newname;
>> >>>>> > > char *tempname;
>> >>>>> > > tree decl;
>> >>>>> > >
>> >>>>> > > asprintf (&tempname, "%s.varargs", name);
>> >>>>> > > newname = ggc_strdup (tempname);
>> >>>>> > > free (tempname);
>> >>>>> > >
>> >>>>> > > /* We need sth that can be pointed to for va_start. */
>> >>>>> > >
>> >>>>> > > /**************** CHANGED CODE in GCC-4.7.2 ***************/
>> >>>>> > > decl = build_fake_var_decl (ptr_type_node);
>> >>>>> > >
>> >>>>> > > /************ ORIGINAL CODE in GCC-4.6.2 *******************
>> >>>>> > > /* decl = create_tmp_var_raw (ptr_type_node, name);
>> >>>>> > > get_var_ann (decl);
>> >>>>> > > */
>> >>>>> > >
>> >>>>> > > argvi = new_var_info (decl, newname);
>> >>>>> > > argvi->offset = fi_parm_base + num_args;
>> >>>>> > > argvi->size = ~0;
>> >>>>> > > argvi->is_full_var = true;
>> >>>>> > > argvi->is_heap_var = true;
>> >>>>> > > argvi->fullsize = vi->fullsize;
>> >>>>> > > gcc_assert (prev_vi->offset < argvi->offset);
>> >>>>> > > prev_vi->next = argvi;
>> >>>>> > > prev_vi = argvi;
>> >>>>> > > }
>> >>>>> > >
>> >>>>> > > return vi;
>> >>>>> > >
>> >>>>> > >
>> >>>>> > > So I made the same changes in the pass where this fragment was
>> >>>>> > > used.
>> >>>>> > > But after making the changes the pass is now giving an "internal
>> >>>>> > > compiler error" and a "segmentation fault" at runtime.
>> >>>>> > >
>> >>>>> > > After debugging I could narrow it down to the function
>> >>>>> > > build_fake_var_decl() and to be specific at the memory
>> >>>>> > > allocation
>> >>>>> > > statement highlighted below.
>> >>>>> > >
>> >>>>> > >
>> >>>>> > > tree
>> >>>>> > > build_fake_var_decl (tree type)
>> >>>>> > > {
>> >>>>> > > /************************ My debugging showed that the control
>> >>>>> > > came
>> >>>>> > > here *********************/
>> >>>>> > > tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct
>> >>>>> > > tree_var_decl);
>> >>>>> > > /************************ But did not come here
>> >>>>> > > **********************************************************/
>> >>>>> > > memset (decl, 0, sizeof (struct tree_var_decl));
>> >>>>> > > TREE_SET_CODE (decl, VAR_DECL);
>> >>>>> > > TREE_TYPE (decl) = type;
>> >>>>> > > DECL_UID (decl) = allocate_decl_uid ();
>> >>>>> > > SET_DECL_PT_UID (decl, -1);
>> >>>>> > > layout_decl (decl, 0);
>> >>>>> > > return decl;
>> >>>>> > > }
>> >>>>> > >
>> >>>>> > > The builf_fake_var_decl() function is a gcc function defined in
>> >>>>> > > tree-ssa-structalias.c. To be able to use it in my pass, I
>> >>>>> > > removed the
>> >>>>> > > keyword static in its definition.
>> >>>>> > >
>> >>>>> > > I cannot figure out what can possibly cause this error in the
>> >>>>> > > XOBNEW function.
>> >>>>> > >
>> >>>>> > > Please help!!!
>> >>>>> >
>> >>>>> > Don't use build_fake_var_decl, use what 4.6 did,
>> >>>>> > create_tmp_var_raw.
>> >>>>> >
>> >>>>> > Richard.
>> >>>>> >
>> >>>>> >
>> >>>>>
>> >>>>> But 4.6 used get_var_ann() also along with create_tmp_var_raw()
>> >>>>> which
>> >>>>> has been removed from 4.7.
>> >>>>
>> >>>>
>> >>>> I would like to clarify my above statement by saying that 4.6 used 2
>> >>>> functions [ie. create_tmp_var_raw() and get_var_ann()] whereas 4.7
>> >>>> used only one function [build_fake_var_decl()] for the same purpose.
>> >>>> Now in 4.7 get_var_ann() is unavailable. So is it safe to use only
>> >>>> create_tmp_var_raw(). In other words, was get_var_ann() a redundant
>> >>>> function in 4.6?
>> >>>
>> >>> The whole function is very special for tree-ssa-structalias.c. I have
>> >>> no idea
>> >>> what your pass does, but unless it closely resembles
>> >>> tree-ssa-structalias.c
>> >>> and shares its internal data structures you shouldn't blindly copy
>> >>> over what
>> >>> tree-ssa-structalias.c does (well, at least not without understanding
>> >>> what you
>> >>> are doing).
>> >>>
>> >>> What do you think you are doing with the copy of that code?
>> >>>
>> >>> Richard.
>> >>>
>> >>>>
>> >>>>>
>> >>
>> >>
>> >> The copy of the above code is from function create_function_info_for()
>> >> in tree-ssa-structalias.c which is used to create variables for a
>> >> function in its tree. In the pass there is a similar function named
>> >> cs_create_func_info_for() used for the same purpose, except it does
>> >> not create variables for all the cases. In other words some portions
>> >> from the original function is omitted. Also the data structure
>> >> varinfo_t is modified a bit to suite the pass and renamed as
>> >> csvarinfo_t. I have copied the function from my pass below,
>> >> highlighting the difference from the original function using comments.
>> >
>> > Well, then you can literally copy the original function. Just make sure
>> > to also copy and initialize and free the obstack it uses.
>> >
>>
>>
>> Thank you!!!!! The initializing and freeing obstack was the problem.
>> So with that and after removing a few more glitches the pass is now
>> running!!!
>>
>>
>> >> /* Creation function node for DECL, using NAME, and return the index
>> >> of the variable we've created for the function. */
>> >> static csvarinfo_t
>> >> cs_create_func_info_for (tree decl, const char *name)
>> >> {
>> >> csvarinfo_t vi, prev_vi;
>> >> tree arg;
>> >> unsigned int i;
>> >> bool is_varargs = false;
>> >> unsigned int num_args = count_num_arguments (decl, &is_varargs);
>> >>
>> >> /* Create the variable info. */
>> >> vi = cs_new_var_info (decl, name);
>> >> vi->offset = 0;
>> >> vi->size = 1;
>> >> vi->fullsize = num_args + 1;
>> >> vi->may_have_pointers = false;
>> >> if (is_varargs)
>> >> vi->fullsize = ~0;
>> >> cs_insert_vi_for_tree (vi->decl, vi);
>> >>
>> >> prev_vi = vi
>> >>
>> >> /************ There were portions in original code with the
>> >> following comments: **************
>> >>
>> >> 1. Create a variable for things the function clobbers and one
>> >> for things the function uses.
>> >>
>> >> 2. And one for the static chain.
>> >>
>> >> 3. Create a variable for the return var.
>> >>
>> >>
>> >> *******************************************************************************************************/
>> >>
>> >> /* Set up variables for each argument. */
>> >> arg = DECL_ARGUMENTS (decl);
>> >> for (i = 1; i < num_args + 1; i++) {
>> >> csvarinfo_t argvi;
>> >> tree argdecl = decl;
>> >>
>> >> if (arg)
>> >> argdecl = arg;
>> >>
>> >> argvi = cs_new_var_info (argdecl, alias_get_name (argdecl));
>> >> argvi->offset = i;
>> >> argvi->size = 1;
>> >> argvi->is_full_var = true;
>> >> argvi->fullsize = vi->fullsize;
>> >> if (arg)
>> >> argvi->may_have_pointers = true;
>> >> gcc_assert (prev_vi->offset < argvi->offset);
>> >> prev_vi->next = argvi;
>> >> prev_vi = argvi;
>> >> if (arg) {
>> >> cs_insert_vi_for_tree (arg, argvi);
>> >> arg = DECL_CHAIN (arg);
>> >> }
>> >> }
>> >>
>> >> /* Add one representative for all further args. */
>> >> if (is_varargs) {
>> >> csvarinfo_t argvi;
>> >> const char *newname;
>> >> char *tempname;
>> >> tree decl;
>> >>
>> >> asprintf (&tempname, "%s.varargs", name);
>> >> newname = ggc_strdup (tempname);
>> >> free (tempname);
>> >>
>> >> /* We need sth that can be pointed to for va_start. */
>> >> decl = create_tmp_var_raw (ptr_type_node, name);
>> >> get_var_ann (decl);
>> >>
>> >> argvi = cs_new_var_info (decl, newname);
>> >> argvi->offset = 1 + num_args;
>> >> argvi->size = ~0;
>> >> argvi->is_full_var = true;
>> >> argvi->is_heap_var = true;
>> >> argvi->fullsize = vi->fullsize;
>> >> gcc_assert (prev_vi->offset < argvi->offset);
>> >> prev_vi->next = argvi;
>> >> prev_vi = argvi;
>> >> }
>> >>
>> >> return vi;
>> >> }
>> >>
>> >>
>> >> Sudakshina Das
