[17/18] introduce block_chainon and use BLOCK_CHAIN more

BLOCKs have a TREE_CHAIN and a TREE_TYPE; TREE_TYPE is useless for
blocks, but we can't remove TREE_TYPE without also removing TREE_CHAIN.
This patch lays the groundwork to do just that.  It changes places that
use chainon on BLOCKs to use block_chainon, which works identically to
chainon except it uses BLOCK_CHAIN.  And it fixes up a few places that
used TREE_CHAIN when they meant BLOCK_CHAIN.

-Nathan

gcc/ada/
	* gcc-interface/utils.c (gnat_poplevel): Use block_chainon.

gcc/
	* function.h (block_chainon): Declare.
	* function.c (block_chainon): Define.

gcc/cp/
	* decl.c (poplevel): Use block_chainon.

gcc/fortran/
	* f95-lang.c (poplevel): Use BLOCK_CHAIN and block_chainon.

gcc/java/
	* decl.c (poplevel): Use BLOCK_CHAIN and block_chainon.

On Fri, Mar 11, 2011 at 5:23 AM, Nathan Froyd <froydnj@codesourcery.com> wrote:
> BLOCKs have a TREE_CHAIN and a TREE_TYPE; TREE_TYPE is useless for
> blocks, but we can't remove TREE_TYPE without also removing TREE_CHAIN.
> This patch lays the groundwork to do just that.  It changes places that
> use chainon on BLOCKs to use block_chainon, which works identically to
> chainon except it uses BLOCK_CHAIN.  And it fixes up a few places that
> used TREE_CHAIN when they meant BLOCK_CHAIN.

The middle-end parts are ok.  Any particular reason why you choose
function.[ch] for block_chainon and not tree.[ch]?

Thanks,
Richard.

> -Nathan
>
> gcc/ada/
>        * gcc-interface/utils.c (gnat_poplevel): Use block_chainon.
>
> gcc/
>        * function.h (block_chainon): Declare.
>        * function.c (block_chainon): Define.
>
> gcc/cp/
>        * decl.c (poplevel): Use block_chainon.
>
> gcc/fortran/
>        * f95-lang.c (poplevel): Use BLOCK_CHAIN and block_chainon.
>
> gcc/java/
>        * decl.c (poplevel): Use BLOCK_CHAIN and block_chainon.
>
> diff --git a/gcc/ada/gcc-interface/utils.c b/gcc/ada/gcc-interface/utils.c
> index eac87e0..dd06ca3 100644
> --- a/gcc/ada/gcc-interface/utils.c
> +++ b/gcc/ada/gcc-interface/utils.c
> @@ -395,8 +395,8 @@ gnat_poplevel (void)
>   else if (BLOCK_VARS (block) == NULL_TREE)
>     {
>       BLOCK_SUBBLOCKS (level->chain->block)
> -       = chainon (BLOCK_SUBBLOCKS (block),
> -                  BLOCK_SUBBLOCKS (level->chain->block));
> +       = block_chainon (BLOCK_SUBBLOCKS (block),
> +                        BLOCK_SUBBLOCKS (level->chain->block));
>       BLOCK_CHAIN (block) = free_block_chain;
>       free_block_chain = block;
>     }
> diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
> index a0ef39f..de96ac2 100644
> --- a/gcc/cp/decl.c
> +++ b/gcc/cp/decl.c
> @@ -794,7 +794,7 @@ poplevel (int keep, int reverse, int functionbody)
>     }
>   else if (block)
>     current_binding_level->blocks
> -      = chainon (current_binding_level->blocks, block);
> +      = block_chainon (current_binding_level->blocks, block);
>
>   /* If we did not make a block for the level just exited,
>      any blocks made for inner levels
> @@ -803,7 +803,7 @@ poplevel (int keep, int reverse, int functionbody)
>      of something else.  */
>   else if (subblocks)
>     current_binding_level->blocks
> -      = chainon (current_binding_level->blocks, subblocks);
> +      = block_chainon (current_binding_level->blocks, subblocks);
>
>   /* Each and every BLOCK node created here in `poplevel' is important
>      (e.g. for proper debugging information) so if we created one
> diff --git a/gcc/fortran/f95-lang.c b/gcc/fortran/f95-lang.c
> index 687f60b..aebe397 100644
> --- a/gcc/fortran/f95-lang.c
> +++ b/gcc/fortran/f95-lang.c
> @@ -444,7 +444,7 @@ poplevel (int keep, int reverse, int functionbody)
>
>   /* Record the BLOCK node just built as the subblock its enclosing scope.  */
>   for (subblock_node = subblock_chain; subblock_node;
> -       subblock_node = TREE_CHAIN (subblock_node))
> +       subblock_node = BLOCK_CHAIN (subblock_node))
>     BLOCK_SUPERCONTEXT (subblock_node) = block_node;
>
>   /* Clear out the meanings of the local variables of this level.  */
> @@ -475,7 +475,7 @@ poplevel (int keep, int reverse, int functionbody)
>   else if (block_node)
>     {
>       current_binding_level->blocks
> -       = chainon (current_binding_level->blocks, block_node);
> +       = block_chainon (current_binding_level->blocks, block_node);
>     }
>
>   /* If we did not make a block for the level just exited, any blocks made for
> @@ -484,7 +484,7 @@ poplevel (int keep, int reverse, int functionbody)
>      else.  */
>   else if (subblock_chain)
>     current_binding_level->blocks
> -      = chainon (current_binding_level->blocks, subblock_chain);
> +      = block_chainon (current_binding_level->blocks, subblock_chain);
>   if (block_node)
>     TREE_USED (block_node) = 1;
>
> diff --git a/gcc/function.c b/gcc/function.c
> index 3f721fb..094cf74 100644
> --- a/gcc/function.c
> +++ b/gcc/function.c
> @@ -4167,6 +4167,34 @@ blocks_nreverse (tree t)
>   return prev;
>  }
>
> +/* Concatenate two chains of blocks (chained through BLOCK_CHAIN)
> +   by modifying the last node in chain 1 to point to chain 2.  */
> +
> +tree
> +block_chainon (tree op1, tree op2)
> +{
> +  tree t1;
> +
> +  if (!op1)
> +    return op2;
> +  if (!op2)
> +    return op1;
> +
> +  for (t1 = op1; BLOCK_CHAIN (t1); t1 = BLOCK_CHAIN (t1))
> +    continue;
> +  BLOCK_CHAIN (t1) = op2;
> +
> +#ifdef ENABLE_TREE_CHECKING
> +  {
> +    tree t2;
> +    for (t2 = op2; t2; t2 = BLOCK_CHAIN (t2))
> +      gcc_assert (t2 != t1);
> +  }
> +#endif
> +
> +  return op1;
> +}
> +
>  /* Count the subblocks of the list starting with BLOCK.  If VECTOR is
>    non-NULL, list them all into VECTOR, in a depth-first preorder
>    traversal of the block tree.  Also clear TREE_ASM_WRITTEN in all
> diff --git a/gcc/function.h b/gcc/function.h
> index 6e7f539..73af294 100644
> --- a/gcc/function.h
> +++ b/gcc/function.h
> @@ -713,6 +713,7 @@ extern void number_blocks (tree);
>
>  extern void clear_block_marks (tree);
>  extern tree blocks_nreverse (tree);
> +extern tree block_chainon (tree, tree);
>
>  /* Return size needed for stack frame based on slots so far allocated.
>    This size counts from zero.  It is not rounded to STACK_BOUNDARY;
> diff --git a/gcc/java/decl.c b/gcc/java/decl.c
> index a17b826..6e94dff 100644
> --- a/gcc/java/decl.c
> +++ b/gcc/java/decl.c
> @@ -1481,7 +1481,7 @@ poplevel (int keep, int reverse, int functionbody)
>
>   /* In each subblock, record that this is its superior.  */
>
> -  for (link = subblocks; link; link = TREE_CHAIN (link))
> +  for (link = subblocks; link; link = BLOCK_CHAIN (link))
>     BLOCK_SUPERCONTEXT (link) = block;
>
>   /* Clear out the meanings of the local variables of this level.  */
> @@ -1545,7 +1545,7 @@ poplevel (int keep, int reverse, int functionbody)
>       if (block)
>        {
>          current_binding_level->blocks
> -           = chainon (current_binding_level->blocks, block);
> +           = block_chainon (current_binding_level->blocks, block);
>        }
>       /* If we did not make a block for the level just exited,
>         any blocks made for inner levels
> @@ -1554,7 +1554,7 @@ poplevel (int keep, int reverse, int functionbody)
>         of something else.  */
>       else if (subblocks)
>        current_binding_level->blocks
> -         = chainon (current_binding_level->blocks, subblocks);
> +         = block_chainon (current_binding_level->blocks, subblocks);
>
>       if (bind)
>        java_add_stmt (bind);
> --
> 1.7.0.4
>
>

On Fri, Mar 11, 2011 at 02:15:20PM +0100, Richard Guenther wrote:
> On Fri, Mar 11, 2011 at 5:23 AM, Nathan Froyd <froydnj@codesourcery.com> wrote:
> > BLOCKs have a TREE_CHAIN and a TREE_TYPE; TREE_TYPE is useless for
> > blocks, but we can't remove TREE_TYPE without also removing TREE_CHAIN.
> > This patch lays the groundwork to do just that.  It changes places that
> > use chainon on BLOCKs to use block_chainon, which works identically to
> > chainon except it uses BLOCK_CHAIN.  And it fixes up a few places that
> > used TREE_CHAIN when they meant BLOCK_CHAIN.
> 
> The middle-end parts are ok.  Any particular reason why you choose
> function.[ch] for block_chainon and not tree.[ch]?

Because block_nreverse was already in function.[ch].  I'm not
particularly wedded to the location and can move it if you like (I did
spend some time looking through tree.[ch] before rgrep'ing and
remembering that block_nreverse was in a funny location...).

-Nathan

>>>>> "Nathan" == Nathan Froyd <froydnj@codesourcery.com> writes:

Nathan> gcc/java/
Nathan> 	* decl.c (poplevel): Use BLOCK_CHAIN and block_chainon.

This is ok.

Tom

> gcc/ada/
> 	* gcc-interface/utils.c (gnat_poplevel): Use block_chainon.

OK, thanks.