From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2140) id 330343858C3A; Fri, 23 Jun 2023 20:13:22 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 330343858C3A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1687551202; bh=DVsZ4TreRcw9DgG9G51tKObhoGGs3hZoVbliAcJrthk=; h=From:To:Subject:Date:From; b=tY43Y+WT6no2H7u3Rbg56uIpy9hVKpMu2vSw0YTyd/oe4gSObtZgol0xnE0ZR/Scw qSJL3QJNaSJOw+TOz+yKcXOb8LS3DAplKDkA1n2V8WTfQaC8a3qD5Vo0a0yE/cgBz/ uOJBiF84Kh4GWYGffliu1a4acqBFhGhlPo6p6/dE= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Alexandre Oliva To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] Add leafy mode for zero-call-used-regs X-Act-Checkin: gcc X-Git-Author: Alexandre Oliva X-Git-Refname: refs/users/aoliva/heads/testme X-Git-Oldrev: 3eac4e94fb54dc094a36b117b4ea0bfb0a7870e2 X-Git-Newrev: b56e58d510f090bd70470dcb02b23253946883da Message-Id: <20230623201322.330343858C3A@sourceware.org> Date: Fri, 23 Jun 2023 20:13:22 +0000 (GMT) List-Id: https://gcc.gnu.org/g:b56e58d510f090bd70470dcb02b23253946883da commit b56e58d510f090bd70470dcb02b23253946883da Author: Alexandre Oliva Date: Fri Jun 23 17:10:21 2023 -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 | 28 +++++++++++++++++++--- 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, 101 insertions(+), 3 deletions(-) diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 852f6b629be..b30191b6850 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -4349,7 +4349,7 @@ through registers. In order to satisfy users with different security needs and control the run-time overhead at the same time, the @var{choice} parameter provides a flexible way to choose the subset of the call-used registers to be zeroed. -The three basic values of @var{choice} are: +The four basic values of @var{choice} are: @itemize @bullet @item @@ -4362,10 +4362,14 @@ the function. @item @samp{all} zeros all call-used registers. + +@item +@samp{leafy} behaves like @samp{used} in a leaf function, and like +@samp{all} in a nonleaf function. @end itemize In addition to these three basic choices, it is possible to modify -@samp{used} or @samp{all} as follows: +@samp{used}, @samp{all}, and @samp{leafy} as follows: @itemize @bullet @item @@ -4412,10 +4416,28 @@ 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. +@samp{all-gpr-arg}, @samp{leafy-arg}, and @samp{leafy-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 2e650bf1c48..0d2dab1b99d 100644 --- a/gcc/flag-types.h +++ b/gcc/flag-types.h @@ -348,6 +348,7 @@ 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; @@ -356,6 +357,10 @@ 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 6a79a8290f6..dd2c1136e07 100644 --- a/gcc/function.cc +++ b/gcc/function.cc @@ -5866,6 +5866,9 @@ 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 3087bdac2c6..ac81d4e4294 100644 --- a/gcc/opts.cc +++ b/gcc/opts.cc @@ -2115,6 +2115,10 @@ 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 +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" } } */