https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65248
Bug ID: 65248
Summary: [5 Regression] Copy relocation in PIE against
protected symbol
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: tmsriram at google dot com
Copy relocation doesn't work with protected symbol and BFD linker
enforces it. GCC 5 uses copy relocation in PIE. It either causes
linker error or run-time error:
[hjl@gnu-6 copyreloc-prot]$ cat x.c
extern int a;
extern void bar (void);
int main()
{
bar ();
if (a != 30)
__builtin_abort();
return 0;
}
[hjl@gnu-6 copyreloc-prot]$ cat bar.c
int a;
__attribute__((visibility("protected"))) int a;
void
bar ()
{
a = 30;
}
[hjl@gnu-6 copyreloc-prot]$ make
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -pie -O3 -fpie -c -o x.o x.c
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -pie -O3 -fpic -c -o bar.o
bar.c
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -pie -shared -o libbar.so
bar.o
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -pie -O3 -o x x.o libbar.so
-Wl,-R,.
/usr/local/bin/ld: copy reloc against protected `a' is invalid
/usr/local/bin/ld: failed to set dynamic section sizes: Bad value
collect2: error: ld returned 1 exit status
make: *** [x] Error 1
[hjl@gnu-6 copyreloc-prot]$ /export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -pie -O3 -o x x.o libbar.so
-Wl,-R,. -fuse-ld=gold
[hjl@gnu-6 copyreloc-prot]$ ./x
Aborted
[hjl@gnu-6 copyreloc-prot]$
