From 88ac930a725b8aac8284a2738f03b843f4343dd0 Mon Sep 17 00:00:00 2001 From: Victor Do Nascimento Date: Thu, 17 Nov 2022 14:48:37 +0000 Subject: [PATCH 116/160] arm: Use DWARF numbering convention for pseudo-register representation The patch, initially submitted to trunk in https://sourceware.org/pipermail/binutils/2022-July/122092.html ensures correct support for handling .save directives for mixed-register type lists involving the ra_auth_code pseudo-register, whereby the support first introduced in 2.39 (https://sourceware.org/pipermail/binutils/2022-May/120672.html) led to the generation of unwinder code popping registers in reversed order. gas/Changelog: * config/tc-arm.c (REG_RA_AUTH_CODE): New. (parse_dot_save): Likewise. (parse_reg_list): Remove obsolete code. (reg_names): Set ra_auth_code to 143. (s_arm_unwind_save): Handle core and pseudo-register lists via parse_dot_save. (s_arm_unwind_save_mixed): Deleted. (s_arm_unwind_save_pseudo): Handle one register at a time. * testsuite/gas/arm/unwind-pacbti-m-readelf.d: Fix test. * testsuite/gas/arm/unwind-pacbti-m.d: Likewise. (cherry picked from commit 3a368c4c248f6e9f4bda3a5369befa17a4560293) --- gas/config/tc-arm.c | 159 ++++++++++-------- .../gas/arm/unwind-pacbti-m-readelf.d | 4 +- gas/testsuite/gas/arm/unwind-pacbti-m.d | 2 +- 3 files changed, 95 insertions(+), 70 deletions(-) --- a/gas/config/tc-arm.c +++ b/gas/config/tc-arm.c @@ -742,6 +742,7 @@ const char * const reg_expected_msgs[] = #define REG_SP 13 #define REG_LR 14 #define REG_PC 15 +#define REG_RA_AUTH_CODE 143 /* ARM instructions take 4bytes in the object file, Thumb instructions take 2: */ @@ -1943,21 +1944,6 @@ parse_reg_list (char ** strp, enum reg_l reg = arm_reg_parse (&str, rt); - /* Skip over allowed registers of alternative types in mixed-type - register lists. */ - if (reg == FAIL && rt == REG_TYPE_PSEUDO - && ((reg = arm_reg_parse (&str, REG_TYPE_RN)) != FAIL)) - { - cur_reg = reg; - continue; - } - else if (reg == FAIL && rt == REG_TYPE_RN - && ((reg = arm_reg_parse (&str, REG_TYPE_PSEUDO)) != FAIL)) - { - cur_reg = reg; - continue; - } - if (etype == REGLIST_CLRM) { if (reg == REG_SP || reg == REG_PC) @@ -4139,7 +4125,6 @@ s_arm_unwind_fnstart (int ignored ATTRIB unwind.sp_restored = 0; } - /* Parse a handlerdata directive. Creates the exception handling table entry for the function. */ @@ -4297,15 +4282,19 @@ s_arm_unwind_personality (int ignored AT /* Parse a directive saving pseudo registers. */ static void -s_arm_unwind_save_pseudo (long range) +s_arm_unwind_save_pseudo (int regno) { valueT op; - if (range & (1 << 12)) + switch (regno) { + case REG_RA_AUTH_CODE: /* Opcode for restoring RA_AUTH_CODE. */ op = 0xb4; add_unwind_opcode (op, 1); + break; + default: + as_bad (_("Unknown register %d encountered\n"), regno); } } @@ -4375,6 +4364,80 @@ s_arm_unwind_save_core (long range) } } +/* Implement correct handling of .save lists enabling the split into +sublists where necessary, while preserving correct sublist ordering. */ + +static void +parse_dot_save (char **str_p, int prev_reg) +{ + long core_regs = 0; + int reg; + int in_range = 0; + + if (**str_p == ',') + *str_p += 1; + if (**str_p == '}') + { + *str_p += 1; + return; + } + + while ((reg = arm_reg_parse (str_p, REG_TYPE_RN)) != FAIL) + { + if (!in_range) + { + if (core_regs & (1 << reg)) + as_tsktsk (_("Warning: duplicated register (r%d) in register list"), + reg); + else if (reg <= prev_reg) + as_tsktsk (_("Warning: register list not in ascending order")); + + core_regs |= (1 << reg); + prev_reg = reg; + if (skip_past_char(str_p, '-') != FAIL) + in_range = 1; + else if (skip_past_comma(str_p) == FAIL) + first_error (_("bad register list")); + } + else + { + int i; + if (reg <= prev_reg) + first_error (_("bad range in register list")); + for (i = prev_reg + 1; i <= reg; i++) + { + if (core_regs & (1 << i)) + as_tsktsk (_("Warning: duplicated register (r%d) in register list"), + i); + else + core_regs |= 1 << i; + } + in_range = 0; + } + } + if (core_regs) + { + /* Higher register numbers go in higher memory addresses. When splitting a list, + right-most sublist should therefore be .saved first. Use recursion for this. */ + parse_dot_save (str_p, reg); + /* We're back from recursion, so emit .save insn for sublist. */ + s_arm_unwind_save_core (core_regs); + return; + } + /* Handle pseudo-regs, under assumption these are emitted singly. */ + else if ((reg = arm_reg_parse (str_p, REG_TYPE_PSEUDO)) != FAIL) + { + /* Recurse for remainder of input. Note: No assumption is made regarding which + register in core register set holds pseudo-register. It's not considered in + ordering check beyond ensuring it's not sandwiched between 2 consecutive + registers. */ + parse_dot_save (str_p, prev_reg + 1); + s_arm_unwind_save_pseudo (reg); + return; + } + else + as_bad (BAD_SYNTAX); +} /* Parse a directive saving FPA registers. */ @@ -4716,39 +4779,13 @@ s_arm_unwind_save_mmxwcg (void) ignore_rest_of_line (); } -/* Convert range and mask_range into a sequence of s_arm_unwind_core - and s_arm_unwind_pseudo operations. We assume that mask_range will - not have consecutive bits set, or that one operation per bit is - acceptable. */ - -static void -s_arm_unwind_save_mixed (long range, long mask_range) -{ - while (mask_range) - { - long mask_bit = mask_range & -mask_range; - long subrange = range & (mask_bit - 1); - - if (subrange) - s_arm_unwind_save_core (subrange); - - s_arm_unwind_save_pseudo (mask_bit); - range &= ~subrange; - mask_range &= ~mask_bit; - } - - if (range) - s_arm_unwind_save_core (range); -} - /* Parse an unwind_save directive. If the argument is non-zero, this is a .vsave directive. */ static void s_arm_unwind_save (int arch_v6) { - char *peek, *mask_peek; - long range, mask_range; + char *peek; struct reg_entry *reg; bool had_brace = false; @@ -4756,7 +4793,7 @@ s_arm_unwind_save (int arch_v6) as_bad (MISSING_FNSTART); /* Figure out what sort of save we have. */ - peek = mask_peek = input_line_pointer; + peek = input_line_pointer; if (*peek == '{') { @@ -4788,20 +4825,13 @@ s_arm_unwind_save (int arch_v6) case REG_TYPE_PSEUDO: case REG_TYPE_RN: - mask_range = parse_reg_list (&mask_peek, REGLIST_PSEUDO); - range = parse_reg_list (&input_line_pointer, REGLIST_RN); - - if (range == FAIL || mask_range == FAIL) - { - as_bad (_("expected register list")); - ignore_rest_of_line (); - return; - } - - demand_empty_rest_of_line (); - - s_arm_unwind_save_mixed (range, mask_range); - return; + { + if (had_brace) + input_line_pointer++; + parse_dot_save (&input_line_pointer, -1); + demand_empty_rest_of_line (); + return; + } case REG_TYPE_VFD: if (arch_v6) @@ -23993,12 +24023,8 @@ static const struct reg_entry reg_names[ /* XScale accumulator registers. */ REGNUM(acc,0,XSCALE), REGNUM(ACC,0,XSCALE), - /* DWARF ABI defines RA_AUTH_CODE to 143. It also reserves 134-142 for future - expansion. RA_AUTH_CODE here is given the value 143 % 134 to make it easy - for tc_arm_regname_to_dw2regnum to translate to DWARF reg number using - 134 + reg_number should the range 134 to 142 be used for more pseudo regs - in the future. This also helps fit RA_AUTH_CODE into a bitmask. */ - REGDEF(ra_auth_code,12,PSEUDO), + /* AADWARF32 defines RA_AUTH_CODE to 143. */ + REGDEF(ra_auth_code,143,PSEUDO), }; #undef REGDEF #undef REGNUM @@ -27905,7 +27931,6 @@ create_unwind_entry (int have_data) return 0; } - /* Initialize the DWARF-2 unwind information for this procedure. */ void --- a/gas/testsuite/gas/arm/unwind-pacbti-m-readelf.d +++ b/gas/testsuite/gas/arm/unwind-pacbti-m-readelf.d @@ -10,11 +10,11 @@ Unwind section '.ARM.exidx' at offset 0x 0x0 : @0x0 Compact model index: 1 - 0x84 0x00 pop {r14} 0xb4 pop {ra_auth_code} 0x84 0x00 pop {r14} - 0xb4 pop {ra_auth_code} 0xa3 pop {r4, r5, r6, r7} 0xb4 pop {ra_auth_code} + 0x84 0x00 pop {r14} + 0xb4 pop {ra_auth_code} 0xa8 pop {r4, r14} 0xb0 finish --- a/gas/testsuite/gas/arm/unwind-pacbti-m.d +++ b/gas/testsuite/gas/arm/unwind-pacbti-m.d @@ -8,4 +8,4 @@ .*: file format.* Contents of section .ARM.extab: - 0000 (00840281 b40084b4 b0a8b4a3|81028400 b48400b4 a3b4a8b0) 00000000 .* + 0000 (84b40281 84b4a300 b0a8b400|8102b484 00a3b484 00b4a8b0) 00000000 .*