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From: Alexandre Oliva <aoliva@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] Add leafy mode for zero-call-used-regs Date: Thu, 8 Jun 2023 04:47:04 +0000 (GMT) [thread overview] Message-ID: <20230608044704.D58213857352@sourceware.org> (raw) https://gcc.gnu.org/g:d707886095e92e560170820e55b3e1c97defc51a commit d707886095e92e560170820e55b3e1c97defc51a Author: Alexandre Oliva <oliva@adacore.com> Date: Wed Oct 19 20:36:28 2022 -0300 Add leafy mode for zero-call-used-regs Introduce 'leafy' to auto-select between 'used' and 'all' for leaf and nonleaf functions, respectively. for gcc/ChangeLog * doc/extend.texi (zero-call-used-regs): Document leafy and variants thereof. * flag-types.h (zero_regs_flags): Add LEAFY_MODE, as well as LEAFY and variants. * function.cc (gen_call_ued_regs_seq): Set only_used for leaf functions in leafy mode. * opts.cc (zero_call_used_regs_opts): Add leafy and variants. for gcc/testsuite/ChangeLog * c-c++-common/zero-scratch-regs-leafy-1.c: New. * c-c++-common/zero-scratch-regs-leafy-2.c: New. * gcc.target/i386/zero-scratch-regs-leafy-1.c: New. * gcc.target/i386/zero-scratch-regs-leafy-2.c: New. Diff: --- gcc/doc/extend.texi | 22 ++++++++++++++++++++-- gcc/flag-types.h | 5 +++++ gcc/function.cc | 3 +++ gcc/opts.cc | 4 ++++ .../c-c++-common/zero-scratch-regs-leafy-1.c | 15 +++++++++++++++ .../c-c++-common/zero-scratch-regs-leafy-2.c | 21 +++++++++++++++++++++ .../gcc.target/i386/zero-scratch-regs-leafy-1.c | 12 ++++++++++++ .../gcc.target/i386/zero-scratch-regs-leafy-2.c | 16 ++++++++++++++++ 8 files changed, 96 insertions(+), 2 deletions(-) diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index cdbd4b34a35..56aa81c8c37 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -4401,10 +4401,28 @@ zeros all call-used registers that pass arguments. @item all-gpr-arg zeros all call-used general purpose registers that pass arguments. + +@item leafy +Same as @samp{used} in a leaf function, and same as @samp{all} in a +nonleaf function. + +@item leafy-gpr +Same as @samp{used-gpr} in a leaf function, and same as @samp{all-gpr} +in a nonleaf function. + +@item leafy-arg +Same as @samp{used-arg} in a leaf function, and same as @samp{all-arg} +in a nonleaf function. + +@item leafy-gpr-arg +Same as @samp{used-gpr-arg} in a leaf function, and same as +@samp{all-gpr-arg} in a nonleaf function. + @end table -Of this list, @samp{used-arg}, @samp{used-gpr-arg}, @samp{all-arg}, -and @samp{all-gpr-arg} are mainly used for ROP mitigation. +Of this list, @samp{used-arg}, @samp{used-gpr-arg}, @samp{leafy-arg}, +@samp{leafy-gpr-arg}, @samp{all-arg}, and @samp{all-gpr-arg} are mainly +used for ROP mitigation. The default for the attribute is controlled by @option{-fzero-call-used-regs}. @end table diff --git a/gcc/flag-types.h b/gcc/flag-types.h index 78dbdbe90dd..36305de589e 100644 --- a/gcc/flag-types.h +++ b/gcc/flag-types.h @@ -338,6 +338,7 @@ namespace zero_regs_flags { const unsigned int ONLY_GPR = 1UL << 2; const unsigned int ONLY_ARG = 1UL << 3; const unsigned int ENABLED = 1UL << 4; + const unsigned int LEAFY_MODE = 1UL << 5; const unsigned int USED_GPR_ARG = ENABLED | ONLY_USED | ONLY_GPR | ONLY_ARG; const unsigned int USED_GPR = ENABLED | ONLY_USED | ONLY_GPR; const unsigned int USED_ARG = ENABLED | ONLY_USED | ONLY_ARG; @@ -346,6 +347,10 @@ namespace zero_regs_flags { const unsigned int ALL_GPR = ENABLED | ONLY_GPR; const unsigned int ALL_ARG = ENABLED | ONLY_ARG; const unsigned int ALL = ENABLED; + const unsigned int LEAFY_GPR_ARG = ENABLED | LEAFY_MODE | ONLY_GPR | ONLY_ARG; + const unsigned int LEAFY_GPR = ENABLED | LEAFY_MODE | ONLY_GPR; + const unsigned int LEAFY_ARG = ENABLED | LEAFY_MODE | ONLY_ARG; + const unsigned int LEAFY = ENABLED | LEAFY_MODE; } /* Settings of flag_incremental_link. */ diff --git a/gcc/function.cc b/gcc/function.cc index 82102ed78d7..7b03f9e7441 100644 --- a/gcc/function.cc +++ b/gcc/function.cc @@ -5868,6 +5868,9 @@ gen_call_used_regs_seq (rtx_insn *ret, unsigned int zero_regs_type) only_used = zero_regs_type & ONLY_USED; only_arg = zero_regs_type & ONLY_ARG; + if ((zero_regs_type & LEAFY_MODE) && leaf_function_p ()) + only_used = true; + /* For each of the hard registers, we should zero it if: 1. it is a call-used register; and 2. it is not a fixed register; diff --git a/gcc/opts.cc b/gcc/opts.cc index 86b94d62b58..93c78be8b0d 100644 --- a/gcc/opts.cc +++ b/gcc/opts.cc @@ -2114,6 +2114,10 @@ const struct zero_call_used_regs_opts_s zero_call_used_regs_opts[] = ZERO_CALL_USED_REGS_OPT (all-gpr, zero_regs_flags::ALL_GPR), ZERO_CALL_USED_REGS_OPT (all-arg, zero_regs_flags::ALL_ARG), ZERO_CALL_USED_REGS_OPT (all, zero_regs_flags::ALL), + ZERO_CALL_USED_REGS_OPT (leafy-gpr-arg, zero_regs_flags::LEAFY_GPR_ARG), + ZERO_CALL_USED_REGS_OPT (leafy-gpr, zero_regs_flags::LEAFY_GPR), + ZERO_CALL_USED_REGS_OPT (leafy-arg, zero_regs_flags::LEAFY_ARG), + ZERO_CALL_USED_REGS_OPT (leafy, zero_regs_flags::LEAFY), #undef ZERO_CALL_USED_REGS_OPT {NULL, 0U} }; diff --git a/gcc/testsuite/c-c++-common/zero-scratch-regs-leafy-1.c b/gcc/testsuite/c-c++-common/zero-scratch-regs-leafy-1.c new file mode 100644 index 00000000000..c1a0c31ba1c --- /dev/null +++ b/gcc/testsuite/c-c++-common/zero-scratch-regs-leafy-1.c @@ -0,0 +1,15 @@ +/* { dg-do run } */ +/* { dg-options "-O2 -fzero-call-used-regs=leafy" } */ + +volatile int result = 0; +int +__attribute__((noipa)) +foo (int x) +{ + return x; +} +int main() +{ + result = foo (2); + return 0; +} diff --git a/gcc/testsuite/c-c++-common/zero-scratch-regs-leafy-2.c b/gcc/testsuite/c-c++-common/zero-scratch-regs-leafy-2.c new file mode 100644 index 00000000000..d450620c1fc --- /dev/null +++ b/gcc/testsuite/c-c++-common/zero-scratch-regs-leafy-2.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +#include <assert.h> +int result = 0; + +int +__attribute__((noipa)) +__attribute__ ((zero_call_used_regs("leafy"))) +foo1 (int x) +{ + return (x + 1); +} + +int +__attribute__((noipa)) +__attribute__ ((zero_call_used_regs("leafy"))) +foo2 (int x) +{ + return foo1 (x + 2); +} diff --git a/gcc/testsuite/gcc.target/i386/zero-scratch-regs-leafy-1.c b/gcc/testsuite/gcc.target/i386/zero-scratch-regs-leafy-1.c new file mode 100644 index 00000000000..2277710c771 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/zero-scratch-regs-leafy-1.c @@ -0,0 +1,12 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fzero-call-used-regs=leafy -fno-stack-protector -fno-PIC" } */ + +void +foo (void) +{ +} + +/* { dg-final { scan-assembler-not "vzeroall" } } */ +/* { dg-final { scan-assembler-not "%xmm" } } */ +/* { dg-final { scan-assembler-not "xorl\[ \t\]+%" } } */ +/* { dg-final { scan-assembler-not "movl\[ \t\]+%" } } */ diff --git a/gcc/testsuite/gcc.target/i386/zero-scratch-regs-leafy-2.c b/gcc/testsuite/gcc.target/i386/zero-scratch-regs-leafy-2.c new file mode 100644 index 00000000000..24b85c3dbb7 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/zero-scratch-regs-leafy-2.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fzero-call-used-regs=leafy-gpr -fno-stack-protector -fno-PIC" } */ + +extern int bar (int); + +void +foo (void) +{ + int x = bar (0); + if (x) + bar (1); +} + +/* { dg-final { scan-assembler "xorl\[ \t\]+%eax, %eax" } } */ +/* { dg-final { scan-assembler "xorl\[ \t\]+%edx, %edx" } } */ +/* { dg-final { scan-assembler "xorl\[ \t\]+%ecx, %ecx" } } */
next reply other threads:[~2023-06-08 4:47 UTC|newest] Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-06-08 4:47 Alexandre Oliva [this message] -- strict thread matches above, loose matches on Subject: below -- 2023-06-23 20:56 Alexandre Oliva 2023-06-23 20:13 Alexandre Oliva 2023-06-09 8:07 Alexandre Oliva 2023-06-09 6:25 Alexandre Oliva 2023-06-09 6:17 Alexandre Oliva 2023-06-08 10:59 Alexandre Oliva 2023-06-08 10:43 Alexandre Oliva 2023-06-08 9:18 Alexandre Oliva 2022-10-25 2:51 Alexandre Oliva 2022-10-20 22:32 Alexandre Oliva 2022-10-20 5:45 Alexandre Oliva 2022-10-20 4:09 Alexandre Oliva
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