Attachment 7654 Details for Bug 15855 – PPP

PPP

PPP (text/plain), 2.82 KB, created by Jeffrey A. Law on 2004-12-02 04:57:19 UTC

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Creator: Jeffrey A. Law

Created: 2004-12-02 04:57:19 UTC

Size: 2.82 KB

patch

obsolete

>        * tree.h (save_eptr, save_filt): Now file scoped statics.
>        (honor_protect_cleanup_actions): Only create save_eptr and
>        save_filt if they do not already exist.
>        (lower_eh_constructs): Wipe all knowledge of save_eptr and
>        save_filt before returning.
>
>Index: tree-eh.c
>===================================================================
>RCS file: /cvs/gcc/gcc/gcc/tree-eh.c,v
>retrieving revision 2.20
>diff -c -p -r2.20 tree-eh.c
>*** tree-eh.c	23 Sep 2004 14:34:19 -0000	2.20
>--- tree-eh.c	2 Dec 2004 04:54:34 -0000
>*************** Boston, MA 02111-1307, USA.  */
>*** 37,42 ****
>--- 37,57 ----
>  #include "langhooks.h"
>  #include "ggc.h"
>  
>+ /* In some circumstances we have to save EH data around a nested
>+    exception.  The EXC_PTR_EXPR and FILTER_EXPR values are saved
>+    into these _DECL nodes.
>+ 
>+    We lazily create this pair of _DECL nodes once per function rather
>+    than creating a new pair of _DECLs each time we need to save the
>+    EXEC_PTR and FILTER.  This can save us literally thousands of _DECL
>+    nodes when we have many inline destructors with an embedded try block.  
>+ 
>+    This is safe as we know the lifetime of the values in these _DECL nodes.
>+    Their lifetimes also ensure that globbing these uses into a single
>+    pair of _DECL nodes requires no additional PHI_NODEs or SSA_NAMEs when
>+    compared to having a pair of _DECL nodes per inline destructor with
>+    an embedded try block.  */
>+ static tree save_eptr, save_filt;
>  
>  /* Nonzero if we are using EH to handle cleanups.  */
>  static int using_eh_for_cleanups_p = 0;
>*************** honor_protect_cleanup_actions (struct le
>*** 807,816 ****
>       we never fallthru from this copy of the finally block.  */
>    if (finally_may_fallthru)
>      {
>!       tree save_eptr, save_filt;
>! 
>!       save_eptr = create_tmp_var (ptr_type_node, "save_eptr");
>!       save_filt = create_tmp_var (integer_type_node, "save_filt");
>  
>        i = tsi_start (finally);
>        x = build (EXC_PTR_EXPR, ptr_type_node);
>--- 822,834 ----
>       we never fallthru from this copy of the finally block.  */
>    if (finally_may_fallthru)
>      {
>!       /* If we have not created _DECLs for saving the EXC_PTR
>! 	 and FILTER_EXPR, create them now.  */
>!       if (!save_eptr)
>! 	{
>! 	  save_eptr = create_tmp_var (ptr_type_node, "save_eptr");
>! 	  save_filt = create_tmp_var (integer_type_node, "save_filt");
>! 	}
>  
>        i = tsi_start (finally);
>        x = build (EXC_PTR_EXPR, ptr_type_node);
>*************** lower_eh_constructs (void)
>*** 1644,1649 ****
>--- 1662,1672 ----
>    htab_delete (finally_tree);
>  
>    collect_eh_region_array ();
>+ 
>+   /* Wipe the DECLs we use for saving the EXC_PTR and FILTER_EXPR
>+      to ensure we create new ones for the next function.  */
>+   save_eptr = NULL;
>+   save_filt = NULL;
>  }
>  
>  struct tree_opt_pass pass_lower_eh =

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