From: Yichao Yu Date: Wed, 18 May 2022 14:00:00 +0000 (+0100) Subject: [AArch64] Return the regnum for PC (32) on aarch64 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1fe8486103e482bcd6cd74fdbf79a7d2ab9b111f;p=binutils-gdb.git [AArch64] Return the regnum for PC (32) on aarch64 This will allow the unwind info to explicitly specify a different value for the return address from the link register. Such usage, although uncommon, is valid and useful for signal frames. It is also supported by aadwarf64 from ARM (Note 9 in [1]). Ref https://sourceware.org/pipermail/gdb/2022-May/050091.html [1] https://github.com/ARM-software/abi-aa/blob/2022Q1/aadwarf64/aadwarf64.rst#dwarf-register-names Signed-off-by: Luis Machado --- diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c index d0995bb9c48..c3abd3a4256 100644 --- a/gdb/aarch64-tdep.c +++ b/gdb/aarch64-tdep.c @@ -2219,6 +2219,9 @@ aarch64_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg) if (reg == AARCH64_DWARF_SP) return AARCH64_SP_REGNUM; + if (reg == AARCH64_DWARF_PC) + return AARCH64_PC_REGNUM; + if (reg >= AARCH64_DWARF_V0 && reg <= AARCH64_DWARF_V0 + 31) return AARCH64_V0_REGNUM + reg - AARCH64_DWARF_V0; diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h index 057525e68f4..8efacd5de0f 100644 --- a/gdb/aarch64-tdep.h +++ b/gdb/aarch64-tdep.h @@ -34,6 +34,7 @@ struct regset; /* AArch64 Dwarf register numbering. */ #define AARCH64_DWARF_X0 0 #define AARCH64_DWARF_SP 31 +#define AARCH64_DWARF_PC 32 #define AARCH64_DWARF_RA_SIGN_STATE 34 #define AARCH64_DWARF_V0 64 #define AARCH64_DWARF_SVE_VG 46 diff --git a/gdb/testsuite/gdb.arch/aarch64-unwind-pc.S b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.S new file mode 100644 index 00000000000..6cc4f80e349 --- /dev/null +++ b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.S @@ -0,0 +1,48 @@ +/* Copyright 2022 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + + .text + .globl main + .type main,#function +main: + .cfi_startproc + stp x29, x30, [sp, -16]! + .cfi_def_cfa sp, 16 + .cfi_offset x29, 0 + .cfi_offset x30, 8 + bl test_func + ldp x29, x30, [sp], 16 + .cfi_restore x29 + .cfi_restore x30 + .cfi_def_cfa sp, 0 + mov x0, 0 + ret + .cfi_endproc + + .globl test_func +test_func: + .cfi_startproc + // Unwind x30 to a different value + // CFA_val_expression x30 const2u 0x1234 + .cfi_escape 0x16, 30, 0x03, 0x0a, 0x34, 0x12 + // CFA_val_expression pc breg30 0 + .cfi_escape 0x16, 32, 0x02, 0x8e, 0x00 + mov x0, x30 + .cfi_register 32, x0 + mov x30, 0x1234 + ret x0 + .cfi_endproc diff --git a/gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp new file mode 100644 index 00000000000..105b9a9cc3a --- /dev/null +++ b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp @@ -0,0 +1,70 @@ +# Copyright 2022 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# This file is part of the gdb testsuite. + +# Test explicitly unwinding the PC DWARF register on aarch64 + +if {![is_aarch64_target]} then { + verbose "Skipping ${gdb_test_file_name}." + return +} + +standard_testfile .S + +if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } { + return -1 +} + +if ![runto_main] { + return -1 +} + +proc test_reg_vals {} { + gdb_test "p \$pc - &main" "= 8" "p \$pc" + gdb_test "p/x \$x30" "= 0x1234" "p \$x30" +} + +proc test_unwind_pc { inst } { + gdb_test "si" "$inst" "single step" + gdb_test "backtrace" \ + ".*#1.*in main ().*" \ + "backtrace" + gdb_test "up" "in main ().*" "parent frame" + test_reg_vals +} + +# Ready to enter the function +gdb_test "si" "bl test_func" "call site" +# Step through the 3 instructions in the function to make sure that +# we have the same unwind info throughout. +with_test_prefix "1st stepi" { + test_unwind_pc "mov x0, x30" +} +with_test_prefix "2nd stepi" { + test_unwind_pc "mov x30, 0x1234" +} +with_test_prefix "3rd stepi" { + test_unwind_pc "ret x0" +} +# Check again after we returned +with_test_prefix "final" { + # Check that we've stepped out (si prints out the new function name) + gdb_test "si" ".*main *().*" "single step out" + gdb_test "backtrace" \ + "#0\[\t \]+main ().*" \ + "backtrace" + test_reg_vals +}