From d10f3e900b0377b4760a090b0f90371bcef01686 Mon Sep 17 00:00:00 2001 From: qing zhao Date: Fri, 30 Oct 2020 20:41:38 +0100 Subject: Add -fzero-call-used-regs option and zero_call_used_regs function attributes. This new feature causes the compiler to zero a subset of all call-used registers at function return. This is used to increase program security by either mitigating Return-Oriented Programming (ROP) attacks or preventing information leakage through registers. gcc/ChangeLog: 2020-10-30 Qing Zhao H.J.Lu * common.opt: Add new option -fzero-call-used-regs * config/i386/i386.c (zero_call_used_regno_p): New function. (zero_call_used_regno_mode): Likewise. (zero_all_vector_registers): Likewise. (zero_all_st_registers): Likewise. (zero_all_mm_registers): Likewise. (ix86_zero_call_used_regs): Likewise. (TARGET_ZERO_CALL_USED_REGS): Define. * df-scan.c (df_epilogue_uses_p): New function. (df_get_exit_block_use_set): Replace EPILOGUE_USES with df_epilogue_uses_p. * df.h (df_epilogue_uses_p): Declare. * doc/extend.texi: Document the new zero_call_used_regs attribute. * doc/invoke.texi: Document the new -fzero-call-used-regs option. * doc/tm.texi: Regenerate. * doc/tm.texi.in (TARGET_ZERO_CALL_USED_REGS): New hook. * emit-rtl.h (struct rtl_data): New field must_be_zero_on_return. * flag-types.h (namespace zero_regs_flags): New namespace. * function.c (gen_call_used_regs_seq): New function. (class pass_zero_call_used_regs): New class. (pass_zero_call_used_regs::execute): New function. (make_pass_zero_call_used_regs): New function. * optabs.c (expand_asm_reg_clobber_mem_blockage): New function. * optabs.h (expand_asm_reg_clobber_mem_blockage): Declare. * opts.c (zero_call_used_regs_opts): New structure array initialization. (parse_zero_call_used_regs_options): New function. (common_handle_option): Handle -fzero-call-used-regs. * opts.h (zero_call_used_regs_opts): New structure array. * passes.def: Add new pass pass_zero_call_used_regs. * recog.c (valid_insn_p): New function. * recog.h (valid_insn_p): Declare. * resource.c (init_resource_info): Replace EPILOGUE_USES with df_epilogue_uses_p. * target.def (zero_call_used_regs): New hook. * targhooks.c (default_zero_call_used_regs): New function. * targhooks.h (default_zero_call_used_regs): Declare. * tree-pass.h (make_pass_zero_call_used_regs): Declare. gcc/c-family/ChangeLog: 2020-10-30 Qing Zhao H.J.Lu * c-attribs.c (c_common_attribute_table): Add new attribute zero_call_used_regs. (handle_zero_call_used_regs_attribute): New function. gcc/testsuite/ChangeLog: 2020-10-30 Qing Zhao H.J.Lu * c-c++-common/zero-scratch-regs-1.c: New test. * c-c++-common/zero-scratch-regs-10.c: New test. * c-c++-common/zero-scratch-regs-11.c: New test. * c-c++-common/zero-scratch-regs-2.c: New test. * c-c++-common/zero-scratch-regs-3.c: New test. * c-c++-common/zero-scratch-regs-4.c: New test. * c-c++-common/zero-scratch-regs-5.c: New test. * c-c++-common/zero-scratch-regs-6.c: New test. * c-c++-common/zero-scratch-regs-7.c: New test. * c-c++-common/zero-scratch-regs-8.c: New test. * c-c++-common/zero-scratch-regs-9.c: New test. * c-c++-common/zero-scratch-regs-attr-usages.c: New test. * gcc.target/i386/zero-scratch-regs-1.c: New test. * gcc.target/i386/zero-scratch-regs-10.c: New test. * gcc.target/i386/zero-scratch-regs-11.c: New test. * gcc.target/i386/zero-scratch-regs-12.c: New test. * gcc.target/i386/zero-scratch-regs-13.c: New test. * gcc.target/i386/zero-scratch-regs-14.c: New test. * gcc.target/i386/zero-scratch-regs-15.c: New test. * gcc.target/i386/zero-scratch-regs-16.c: New test. * gcc.target/i386/zero-scratch-regs-17.c: New test. * gcc.target/i386/zero-scratch-regs-18.c: New test. * gcc.target/i386/zero-scratch-regs-19.c: New test. * gcc.target/i386/zero-scratch-regs-2.c: New test. * gcc.target/i386/zero-scratch-regs-20.c: New test. * gcc.target/i386/zero-scratch-regs-21.c: New test. * gcc.target/i386/zero-scratch-regs-22.c: New test. * gcc.target/i386/zero-scratch-regs-23.c: New test. * gcc.target/i386/zero-scratch-regs-24.c: New test. * gcc.target/i386/zero-scratch-regs-25.c: New test. * gcc.target/i386/zero-scratch-regs-26.c: New test. * gcc.target/i386/zero-scratch-regs-27.c: New test. * gcc.target/i386/zero-scratch-regs-28.c: New test. * gcc.target/i386/zero-scratch-regs-29.c: New test. * gcc.target/i386/zero-scratch-regs-30.c: New test. * gcc.target/i386/zero-scratch-regs-31.c: New test. * gcc.target/i386/zero-scratch-regs-3.c: New test. * gcc.target/i386/zero-scratch-regs-4.c: New test. * gcc.target/i386/zero-scratch-regs-5.c: New test. * gcc.target/i386/zero-scratch-regs-6.c: New test. * gcc.target/i386/zero-scratch-regs-7.c: New test. * gcc.target/i386/zero-scratch-regs-8.c: New test. * gcc.target/i386/zero-scratch-regs-9.c: New test. --- gcc/targhooks.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'gcc/targhooks.c') diff --git a/gcc/targhooks.c b/gcc/targhooks.c index 5d94fce..4e4d100 100644 --- a/gcc/targhooks.c +++ b/gcc/targhooks.c @@ -56,6 +56,9 @@ along with GCC; see the file COPYING3. If not see #include "tree-ssa-alias.h" #include "gimple-expr.h" #include "memmodel.h" +#include "backend.h" +#include "emit-rtl.h" +#include "df.h" #include "tm_p.h" #include "stringpool.h" #include "tree-vrp.h" @@ -987,6 +990,35 @@ default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED) #endif } +/* The default hook for TARGET_ZERO_CALL_USED_REGS. */ + +HARD_REG_SET +default_zero_call_used_regs (HARD_REG_SET need_zeroed_hardregs) +{ + gcc_assert (!hard_reg_set_empty_p (need_zeroed_hardregs)); + + for (unsigned int regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) + if (TEST_HARD_REG_BIT (need_zeroed_hardregs, regno)) + { + rtx_insn *last_insn = get_last_insn (); + machine_mode mode = GET_MODE (regno_reg_rtx[regno]); + rtx zero = CONST0_RTX (mode); + rtx_insn *insn = emit_move_insn (regno_reg_rtx[regno], zero); + if (!valid_insn_p (insn)) + { + static bool issued_error; + if (!issued_error) + { + issued_error = true; + sorry ("%qs not supported on this target", + "-fzero-call-used_regs"); + } + delete_insns_since (last_insn); + } + } + return need_zeroed_hardregs; +} + rtx default_internal_arg_pointer (void) { -- cgit v1.1