[Bug bootstrap/55792] [4.8 Regression] Bad memory access with profiledbootstrap and LTO

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55792



--- Comment #19 from H.J. Lu <hjl.tools at gmail dot com> 2013-01-09 16:11:06 
UTC ---

The BLOCK tree node is cleared by



(gdb) bt

#0  0x000000336b4882ee in __memset_sse2 () from /lib64/libc.so.6

#1  0x0000000000545fdf in clear_marks ()

    at /export/gnu/import/git/gcc/gcc/ggc-page.c:1815

#2  0x0000000000546621 in ggc_collect ()

    at /export/gnu/import/git/gcc/gcc/ggc-page.c:2086

#3  0x00000000008ad816 in execute_todo (flags=2102)

    at /export/gnu/import/git/gcc/gcc/passes.c:2023

#4  0x00000000008ae175 in execute_one_pass (pass=0x17b9c70)

    at /export/gnu/import/git/gcc/gcc/passes.c:2349

#5  0x00000000008ae2da in execute_pass_list (pass=0x17b9c70)

    at /export/gnu/import/git/gcc/gcc/passes.c:2383

#6  0x00000000008ae30b in execute_pass_list (

    pass=0x16d07e0 <pass_all_optimizations>)

    at /export/gnu/import/git/gcc/gcc/passes.c:2384

#7  0x00000000005da366 in expand_function (node=0x7ffff16f5378)

    at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1641

#8  0x00000000005da821 in expand_all_functions ()

    at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1745

#9  0x00000000005db2ab in compile ()

    at /export/gnu/import/git/gcc/gcc/cgraphunit.c:2043

#10 0x000000000053c60a in lto_main ()

    at /export/gnu/import/git/gcc/gcc/lto/lto.c:3390

#11 0x0000000000999401 in compile_file ()

---Type <return> to continue, or q <return> to quit---

    at /export/gnu/import/git/gcc/gcc/toplev.c:545

#12 0x000000000099b3e4 in do_compile ()

    at /export/gnu/import/git/gcc/gcc/toplev.c:1878

#13 0x000000000099b54f in toplev_main (argc=28, argv=0x7fffffffdc78)

    at /export/gnu/import/git/gcc/gcc/toplev.c:1954

#14 0x0000000000fff958 in main (argc=28, argv=0x7fffffffdc78)

    at /export/gnu/import/git/gcc/gcc/main.c:36

(gdb)



When we remap a block:

static void

remap_block (tree *block, copy_body_data *id)

{

  tree old_block;

  tree new_block;



  /* Make the new block.  */

  old_block = *block;

  new_block = make_node (BLOCK);

  TREE_USED (new_block) = TREE_USED (old_block);

  BLOCK_ABSTRACT_ORIGIN (new_block) = old_block;

  BLOCK_SOURCE_LOCATION (new_block) = BLOCK_SOURCE_LOCATION (old_block);

  BLOCK_NONLOCALIZED_VARS (new_block)

    = vec_safe_copy (BLOCK_NONLOCALIZED_VARS (old_block));

  *block = new_block;



  /* Remap its variables.  */

  BLOCK_VARS (new_block) = remap_decls (BLOCK_VARS (old_block),

                                        &BLOCK_NONLOCALIZED_VARS (new_block),

                                        id);



we didn't register it with GC root.