Re: Correct way to access predecessors of a gimple statement?
Hello Kartik You can use the iterator FOR_EACH_EDGE in this form: FOR_EACH_EDGE (e, ei, bb->preds) where e is an edge ei is edge iterator bb is a basic block. I hope that gave you what you were looking for. Sudakshina Das On Sun, May 5, 2013 at 10:05 AM, Kartik Singhal wrote: > > Hi > > I am trying to implement a GVN algorithm as a plugin for GCC 4.6. > > With help from GCC IRC channel, internals doc and reading the source, > I was able to get a prototype working for the case of a single block. > > Now, I am trying to handle the case of confluence of multiple edges > i.e. obtain redundancy information from multiple paths at a merge > point. I am stuck trying to figure out how to access all the immediate > predecessors of a statement. I have looked into CFG chapter of > internals doc (block and edge), though edge data structure seems to > give a hint, I couldn't clearly find out how to leverage it for my > purpose. Any hints or code example would be a great help. > > If it is of any help, the algorithm is at [1] and my code at [2] > (*very* naive and not considering performance at all in the first > implementation attempt). > > [1]: http://arxiv.org/abs/1303.1880 > [2]: https://github.com/k4rtik/btp-gvn/blob/master/gvn-plugin/plugin.c > > Thanks > -- > Kartik > http://k4rtik.wordpress.com/
A pass that worked in gcc-4.6.2 fails in gcc-4.7.2
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!!!
Sudakshina Das
Re: A pass that worked in gcc-4.6.2 fails in gcc-4.7.2
On Thu, Jan 24, 2013 at 5:15 PM, Richard Biener
wrote:
>
> On Thu, Jan 24, 2013 at 7:06 AM, Sudakshina Das
> 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.
> > Sudakshina Das
Re: A pass that worked in gcc-4.6.2 fails in gcc-4.7.2
On Fri, Jan 25, 2013 at 9:46 AM, Sudakshina Das
wrote:
>
> On Thu, Jan 24, 2013 at 5:15 PM, Richard Biener
> wrote:
> >
> > On Thu, Jan 24, 2013 at 7:06 AM, Sudakshina Das
> > 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?
>
> > > Sudakshina Das
Re: A pass that worked in gcc-4.6.2 fails in gcc-4.7.2
On Fri, Jan 25, 2013 at 8:02 PM, Richard Biener
wrote:
> On Fri, Jan 25, 2013 at 3:05 PM, Sudakshina Das
> wrote:
>> On Fri, Jan 25, 2013 at 9:46 AM, Sudakshina Das
>> wrote:
>>>
>>> On Thu, Jan 24, 2013 at 5:15 PM, Richard Biener
>>> wrote:
>>> >
>>> > On Thu, Jan 24, 2013 at 7:06 AM, Sudakshina Das
>>> > 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
>>> &g
Re: A pass that worked in gcc-4.6.2 fails in gcc-4.7.2
On Fri, Jan 25, 2013 at 9:27 PM, Richard Biener
wrote:
> On Fri, Jan 25, 2013 at 3:57 PM, Sudakshina Das
> wrote:
>> On Fri, Jan 25, 2013 at 8:02 PM, Richard Biener
>> wrote:
>>> On Fri, Jan 25, 2013 at 3:05 PM, Sudakshina Das
>>> wrote:
>>>> On Fri, Jan 25, 2013 at 9:46 AM, Sudakshina Das
>>>> wrote:
>>>>>
>>>>> On Thu, Jan 24, 2013 at 5:15 PM, Richard Biener
>>>>> wrote:
>>>>> >
>>>>> > On Thu, Jan 24, 2013 at 7:06 AM, Sudakshina Das
>>>>> > 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);
>>>>
Re: A pass that worked in gcc-4.6.2 fails in gcc-4.7.2
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!!
Sudakshina
On Sat, Jan 26, 2013 at 1:16 AM, Sudakshina Das
wrote:
>
> On Fri, Jan 25, 2013 at 9:27 PM, Richard Biener
> wrote:
> > On Fri, Jan 25, 2013 at 3:57 PM, Sudakshina Das
> > wrote:
> >> On Fri, Jan 25, 2013 at 8:02 PM, Richard Biener
> >> wrote:
> >>> On Fri, Jan 25, 2013 at 3:05 PM, Sudakshina Das
> >>> wrote:
> >>>> On Fri, Jan 25, 2013 at 9:46 AM, Sudakshina Das
> >>>> wrote:
> >>>>>
> >>>>> On Thu, Jan 24, 2013 at 5:15 PM, Richard Biener
> >>>>> wrote:
> >>>>> >
> >>>>> > On Thu, Jan 24, 2013 at 7:06 AM, Sudakshina Das
> >>>>> > 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;
> >>>>&g
