http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59000
Bug ID: 59000
Summary: lto can't merge user-defined weak builtin functions
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
Assignee: unassigned at gcc dot gnu.org
Reporter: ma.jiang at zte dot com.cn
Created attachment 31156
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31156&action=edit
first source
User defined built-in implementation cause lto error.
Use source files in the attachment, following commands can reproduce this
problem.
xxx-gcc *.c -O2 -flto -c
xxx-gcc *.o -o tt.mid -r -O2 -flto -nostdlib
lto1: error: two or more sections for .gnu.lto_scalbnf.a2a70fd51cfc1298
(null):0: confused by earlier errors, bailing out
lto-wrapper: ../powerpc-unknown-linux-gnu-gcc returned 1 exit status
collect2: error: lto-wrapper returned 1 exit status
========================================================
It seems that there is a bug in lto_symtab_merge_cgraph_nodes_1 in
lto-symtab.c.
cgraph_node *ce = dyn_cast <cgraph_node> (e);
if (ce && !DECL_BUILT_IN (e->symbol.decl))
lto_cgraph_replace_node (ce, cgraph (prevailing));
if (varpool_node *ve = dyn_cast <varpool_node> (e))
lto_varpool_replace_node (ve, varpool (prevailing));
The function will do real replace only when e is NOT referring to a built-in
function.This is not right, because user can provide their own built-in
implementations which should also be merged. we change DECL_BUILT_IN
(e->symbol.decl)) to DECL_IS_BUILTIN (e->symbol.decl)) to fix this problem, is
the fix ok for the mainstream?
