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| author | Qing Zhao <qing.zhao@oracle.com> | 2022-04-01 16:09:43 +0000 |
|---|---|---|
| committer | Qing Zhao <qing.zhao@oracle.com> | 2022-04-01 16:09:43 +0000 |
| commit | 31933f4f788b6cd64cbb7ee42076997f6d0fe212 (patch) | |
| tree | 5daa89e8f0c580f945687dc4a47f4eb9d1e7032e /gcc/target.def | |
| parent | 413187b0b3c873333253838e4afbf8463b288b59 (diff) | |
| download | gcc-31933f4f788b6cd64cbb7ee42076997f6d0fe212.zip gcc-31933f4f788b6cd64cbb7ee42076997f6d0fe212.tar.gz gcc-31933f4f788b6cd64cbb7ee42076997f6d0fe212.tar.bz2 | |
Add an assertion: the zeroed_hardregs set is a subset of all call used regs.
We should make sure that the hard register set that is actually cleared by
the target hook zero_call_used_regs should be a subset of all call used
registers.
At the same time, update documentation for the target hook
TARGET_ZERO_CALL_USED_REGS.
This new assertion identified a bug in the i386 implemenation, which
incorrectly set the zeroed_hardregs for stack registers. Fixed this bug
in i386 implementation.
gcc/ChangeLog:
2022-04-01 Qing Zhao <qing.zhao@oracle.com>
* config/i386/i386.cc (zero_all_st_registers): Return the value of
num_of_st.
(ix86_zero_call_used_regs): Update zeroed_hardregs set according to
the return value of zero_all_st_registers.
* doc/tm.texi: Update the documentation of TARGET_ZERO_CALL_USED_REGS.
* function.cc (gen_call_used_regs_seq): Add an assertion.
* target.def: Update the documentation of TARGET_ZERO_CALL_USED_REGS.
Diffstat (limited to 'gcc/target.def')
| -rw-r--r-- | gcc/target.def | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/gcc/target.def b/gcc/target.def index 72c2e1e..d85adf3 100644 --- a/gcc/target.def +++ b/gcc/target.def @@ -5122,6 +5122,13 @@ DEFHOOK that could conceivably contain values that are useful to an attacker.\n\ Return the set of registers that were actually cleared.\n\ \n\ +For most targets, the returned set of registers is a subset of\n\ +@var{selected_regs}, however, for some of the targets (for example MIPS),\n\ +clearing some registers that are in the @var{selected_regs} requires\n\ +clearing other call used registers that are not in the @var{selected_regs},\n\ +under such situation, the returned set of registers must be a subset of all\n\ +call used registers.\n\ +\n\ The default implementation uses normal move instructions to zero\n\ all the registers in @var{selected_regs}. Define this hook if the\n\ target has more efficient ways of zeroing certain registers,\n\ |