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| author | Alan Modra <amodra@gmail.com> | 2017-09-21 22:55:45 +0930 |
|---|---|---|
| committer | Alan Modra <amodra@gcc.gnu.org> | 2017-09-21 22:55:45 +0930 |
| commit | c0ced9e080eca19fdd48bae7e959908ce3ab31c7 (patch) | |
| tree | 1c8560e78b817786440bdfb38b31bda0bc11fd44 | |
| parent | 24b0a9e2315ce74ccfa1bbfb0c50957d8723b9a4 (diff) | |
| download | gcc-c0ced9e080eca19fdd48bae7e959908ce3ab31c7.tar.gz | |
PR81996, __builtin_return_address(0) fails
rs6000_return_addr assumes that the stack link is at frame+0, which is
true for count>0. For count==0, rs6000_return_addr is called with
frame==frame_pointer_rtx and the stack link is *not* at frame+0 if
-fstack-protector-all or -fsanitize=address because rs6000.h sets
FRAME_GROWS_DOWNWARD for those options.
PR target/81996
* gcc/config/rs6000/rs6000.c (rs6000_return_addr): Use
stack_pointer_rtx for count 0. Update comments. Break up
large rtl expression.
From-SVN: r253070
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/config/rs6000/rs6000.c | 25 |
2 files changed, 19 insertions, 13 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9a8afeb3c26..ce63706113f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2017-09-21 Alan Modra <amodra@gmail.com> + + PR target/81996 + * gcc/config/rs6000/rs6000.c (rs6000_return_addr): Use + stack_pointer_rtx for count 0. Update comments. Break up + large rtl expression. + 2017-09-19 Martin Liska <mliska@suse.cz> PR c++/81355 diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 32433b294a0..be3912cdb8d 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -22314,24 +22314,23 @@ debug_stack_info (rs6000_stack_t *info) rtx rs6000_return_addr (int count, rtx frame) { - /* Currently we don't optimize very well between prolog and body - code and for PIC code the code can be actually quite bad, so - don't try to be too clever here. */ + /* We can't use get_hard_reg_initial_val for LR when count == 0 if LR + is trashed by the prologue, as it is for PIC on ABI_V4 and Darwin. */ if (count != 0 || ((DEFAULT_ABI == ABI_V4 || DEFAULT_ABI == ABI_DARWIN) && flag_pic)) { cfun->machine->ra_needs_full_frame = 1; - return - gen_rtx_MEM - (Pmode, - memory_address - (Pmode, - plus_constant (Pmode, - copy_to_reg - (gen_rtx_MEM (Pmode, - memory_address (Pmode, frame))), - RETURN_ADDRESS_OFFSET))); + if (count == 0) + /* FRAME is set to frame_pointer_rtx by the generic code, but that + is good for loading 0(r1) only when !FRAME_GROWS_DOWNWARD. */ + frame = stack_pointer_rtx; + rtx prev_frame_addr = memory_address (Pmode, frame); + rtx prev_frame = copy_to_reg (gen_rtx_MEM (Pmode, prev_frame_addr)); + rtx lr_save_off = plus_constant (Pmode, + prev_frame, RETURN_ADDRESS_OFFSET); + rtx lr_save_addr = memory_address (Pmode, lr_save_off); + return gen_rtx_MEM (Pmode, lr_save_addr); } cfun->machine->ra_need_lr = 1; |