| Message ID | b931efa5-d881-c144-57ea-970d2a60f750@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | Place jump tables in RELRO only when targets require local relocation to be placed in a read-write section | expand |
On 1/12/2022 12:20 AM, HAO CHEN GUI via Gcc-patches wrote: > Hi, > This patch sets "relocatable" of jump table to true when targets require local relocation to be placed > in a read-write section - bit 0 is set in reloc_rw_mask. Jump tables are in local relocation, so they > should be placed in RELRO only when both global and local relocation need to be placed in a read-write > section. Bit 1 is always set when bit 0 is set. > Bootstrapped and tested on powerpc64-linux BE/LE and x86 with no regressions. Is this okay for trunk? > Any recommendations? Thanks a lot. > > ChangeLog > 2022-01-12 Haochen Gui <guihaoc@linux.ibm.com> > > gcc/ > * final.c (jumptable_relocatable): Set relocatable to true when > targets require local relocation to be placed in a read-write section. It seems unwise to me to rely on the fact that bit1 is already on when bit0 is on. I realize that's likely just preserving existing behavior, but unless there's a compelling reason, I'd rather do: relocatable = (targetm.asm_out.reloc_rw_mask () & 1) != 0; Which avoids the assumption that if bit0 is on, then bit 1 will always be on. jeff
diff --git a/gcc/final.c b/gcc/final.c index 296a9382e91..e86223cb96b 100644 --- a/gcc/final.c +++ b/gcc/final.c @@ -2141,7 +2141,7 @@ jumptable_relocatable (void) if (!CASE_VECTOR_PC_RELATIVE && !targetm.asm_out.generate_pic_addr_diff_vec () && targetm_common.have_named_sections) - relocatable = targetm.asm_out.reloc_rw_mask (); + relocatable = targetm.asm_out.reloc_rw_mask () == 3; return relocatable; }