From 5f426554fd804d65509875d706d8b8bc3a48393b Mon Sep 17 00:00:00 2001 From: Andre Simoes Dias Vieira Date: Tue, 23 Jun 2020 15:20:17 +0100 Subject: [PATCH] arm: PR target/95646: Do not clobber callee saved registers with CMSE As reported in bugzilla when the -mcmse option is used while compiling for size (-Os) with a thumb-1 target the generated code will clear the registers r7-r10. These however are callee saved and should be preserved accross ABI boundaries. The reason this happens is because these registers are made "fixed" when optimising for size with Thumb-1 in a way to make sure they are not used, as pushing and popping hi-registers requires extra moves to and from LO_REGS. To fix this, this patch uses 'callee_saved_reg_p', which accounts for this optimisation, instead of 'call_used_or_fixed_reg_p'. Be aware of 'callee_saved_reg_p''s definition, as it does still take call used registers into account, which aren't callee_saved in my opinion, so it is a rather misnoemer, works in our advantage here though as it does exactly what we need. Regression tested on arm-none-eabi. Is this OK for trunk? (Will eventually backport to previous versions if stable.) gcc/ChangeLog: 2020-06-19 Andre Vieira PR target/95646 * config/arm/arm.c: (cmse_nonsecure_entry_clear_before_return): Use 'callee_saved_reg_p' instead of 'calL_used_or_fixed_reg_p'. gcc/testsuite/ChangeLog: 2020-06-19 Andre Vieira PR target/95646 * gcc.target/arm/pr95646.c: New test. --- gcc/config/arm/arm.c | 2 +- gcc/testsuite/gcc.target/arm/pr95646.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.target/arm/pr95646.c diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c index 6b7ca82..dac9a6f 100644 --- a/gcc/config/arm/arm.c +++ b/gcc/config/arm/arm.c @@ -26960,7 +26960,7 @@ cmse_nonsecure_entry_clear_before_return (void) continue; if (IN_RANGE (regno, IP_REGNUM, PC_REGNUM)) continue; - if (call_used_or_fixed_reg_p (regno) + if (!callee_saved_reg_p (regno) && (!IN_RANGE (regno, FIRST_VFP_REGNUM, LAST_VFP_REGNUM) || TARGET_HARD_FLOAT)) bitmap_set_bit (to_clear_bitmap, regno); diff --git a/gcc/testsuite/gcc.target/arm/pr95646.c b/gcc/testsuite/gcc.target/arm/pr95646.c new file mode 100644 index 0000000..12d06a0 --- /dev/null +++ b/gcc/testsuite/gcc.target/arm/pr95646.c @@ -0,0 +1,32 @@ +/* { dg-do compile } */ +/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-march=*" } { "-march=armv8-m.base" } } */ +/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-mcpu=*" } { "-mcpu=cortex-m23" } } */ +/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-mfpu=*" } { } } */ +/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-mfloat-abi=*" } { "-mfloat-abi=soft" } } */ +/* { dg-options "-mcpu=cortex-m23 -mcmse" } */ +/* { dg-additional-options "-Os" } */ +/* { dg-final { check-function-bodies "**" "" } } */ + +int __attribute__ ((cmse_nonsecure_entry)) +foo (void) +{ + return 1; +} +/* { { dg-final { scan-assembler-not "mov\tr9, r0" } } */ + +/* +** __acle_se_bar: +** mov (r[0-3]), r9 +** push {\1} +** ... +** pop {(r[0-3])} +** mov r9, \2 +** ... +** bxns lr +*/ +int __attribute__ ((cmse_nonsecure_entry)) +bar (void) +{ + asm ("": : : "r9"); + return 1; +} -- 2.7.4