From da2b2fdf57a96f7a5b6b153e94afb747e212b17f Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Wed, 13 Nov 2013 11:10:55 -0700 Subject: [PATCH] handle an unspecified return address column Debugging PR 16155 further, I found that the DWARF unwinder found the function in question, but thought it had no registers saved (fs->regs.num_regs == 0). It seems to me that if a frame does not specify the return address column, or if the return address column is explicitly marked as DWARF2_FRAME_REG_UNSPECIFIED, then we should set the "undefined_retaddr" flag and let the DWARF unwinder gracefully stop. This patch implements that idea. With this patch the backtrace works properly: (gdb) bt #0 0x0000007fb7ed485c in nanosleep () from /lib64/libc.so.6 #1 0x0000007fb7ed4508 in sleep () from /lib64/libc.so.6 #2 0x00000000004008bc in thread_function (arg=0x4) at threadapply.c:73 #3 0x0000007fb7fad950 in start_thread () from /lib64/libpthread.so.0 #4 0x0000007fb7f0956c in clone () from /lib64/libc.so.6 2013-11-22 Tom Tromey PR backtrace/16155: * dwarf2-frame.c (dwarf2_frame_cache): Set undefined_retaddr if the return address column is unspecified. 2013-11-22 Tom Tromey * gdb.dwarf2/dw2-bad-cfi.c: New file. * gdb.dwarf2/dw2-bad-cfi.exp: New file. * gdb.dwarf2/dw2-bad-cfi.S: New file. --- gdb/ChangeLog | 6 + gdb/dwarf2-frame.c | 4 + gdb/testsuite/ChangeLog | 6 + gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.S | 216 +++++++++++++++++++++++++++++++ gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.c | 28 ++++ gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.exp | 42 ++++++ 6 files changed, 302 insertions(+) create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.S create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.c create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 1260b5c..0b8683d 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,4 +1,10 @@ 2013-11-22 Tom Tromey + + PR backtrace/16155: + * dwarf2-frame.c (dwarf2_frame_cache): Set undefined_retaddr if + the return address column is unspecified. + +2013-11-22 Tom Tromey Pedro Alves PR backtrace/16155 diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c index c4f8771..f185ca6 100644 --- a/gdb/dwarf2-frame.c +++ b/gdb/dwarf2-frame.c @@ -1245,6 +1245,10 @@ incomplete CFI data; unspecified registers (e.g., %s) at %s"), if (fs->retaddr_column < fs->regs.num_regs && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED) cache->undefined_retaddr = 1; + else if (fs->retaddr_column >= fs->regs.num_regs + || (fs->regs.reg[fs->retaddr_column].how + == DWARF2_FRAME_REG_UNSPECIFIED)) + cache->undefined_retaddr = 1; do_cleanups (old_chain); discard_cleanups (reset_cache_cleanup); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 0135ece..74a1e06 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2013-11-22 Tom Tromey + + * gdb.dwarf2/dw2-bad-cfi.c: New file. + * gdb.dwarf2/dw2-bad-cfi.exp: New file. + * gdb.dwarf2/dw2-bad-cfi.S: New file. + 2013-11-22 Pedro Alves PR 16155 diff --git a/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.S b/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.S new file mode 100644 index 0000000..9a97889 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.S @@ -0,0 +1,216 @@ +# This file was created by running dw2-bad-cfi.c +# through 'gcc -g -dA -S', and then hand-editing +# the CFI in "callee" to suit. + + .file "dw2-bad-cfi.c" + .text +.Ltext0: + .globl callee + .type callee, @function +callee: +.LFB0: + .file 1 "dw2-bad-cfi.c" + # dw2-bad-cfi.c:20 + .loc 1 20 0 + .cfi_startproc +# BLOCK 2 seq:0 +# PRED: ENTRY (fallthru) + pushq %rbp +/* + .cfi_def_cfa_offset 16 + .cfi_offset 6, -16 +*/ + movq %rsp, %rbp +/* .cfi_def_cfa_register 6 */ + # dw2-bad-cfi.c:21 + .loc 1 21 0 + popq %rbp +/* .cfi_def_cfa 7, 8 */ + # Our little lies. + .cfi_undefined 6 + .cfi_return_column 6 +# SUCC: EXIT [100.0%] + ret + .cfi_endproc +.LFE0: + .size callee, .-callee + .globl main + .type main, @function +main: +.LFB1: + # dw2-bad-cfi.c:25 + .loc 1 25 0 + .cfi_startproc +# BLOCK 2 seq:0 +# PRED: ENTRY (fallthru) + pushq %rbp + .cfi_def_cfa_offset 16 + .cfi_offset 6, -16 + movq %rsp, %rbp + .cfi_def_cfa_register 6 + # dw2-bad-cfi.c:26 + .loc 1 26 0 + call callee + # dw2-bad-cfi.c:27 + .loc 1 27 0 + movl $0, %eax + # dw2-bad-cfi.c:28 + .loc 1 28 0 + popq %rbp + .cfi_def_cfa 7, 8 +# SUCC: EXIT [100.0%] + ret + .cfi_endproc +.LFE1: + .size main, .-main +.Letext0: + .section .debug_info,"",@progbits +.Ldebug_info0: + .long 0x67 # Length of Compilation Unit Info + .value 0x4 # DWARF version number + .long .Ldebug_abbrev0 # Offset Into Abbrev. Section + .byte 0x8 # Pointer Size (in bytes) + .uleb128 0x1 # (DIE (0xb) DW_TAG_compile_unit) + .long .LASF0 # DW_AT_producer: "GNU C 4.7.2 20121109 (Red Hat 4.7.2-8) -mtune=generic -march=x86-64 -g" + .byte 0x1 # DW_AT_language + .long .LASF1 # DW_AT_name: "dw2-bad-cfi.c" + .long .LASF2 # DW_AT_comp_dir: "/home/tromey/gnu/gdb/devel/binutils-gdb/gdb/testsuite/gdb.dwarf2" + .quad .Ltext0 # DW_AT_low_pc + .quad .Letext0 # DW_AT_high_pc + .long .Ldebug_line0 # DW_AT_stmt_list + .uleb128 0x2 # (DIE (0x2d) DW_TAG_subprogram) + # DW_AT_external + .long .LASF3 # DW_AT_name: "callee" + .byte 0x1 # DW_AT_decl_file (dw2-bad-cfi.c) + .byte 0x13 # DW_AT_decl_line + # DW_AT_prototyped + .quad .LFB0 # DW_AT_low_pc + .quad .LFE0 # DW_AT_high_pc + .uleb128 0x1 # DW_AT_frame_base + .byte 0x9c # DW_OP_call_frame_cfa + # DW_AT_GNU_all_call_sites + .uleb128 0x3 # (DIE (0x46) DW_TAG_subprogram) + # DW_AT_external + .long .LASF4 # DW_AT_name: "main" + .byte 0x1 # DW_AT_decl_file (dw2-bad-cfi.c) + .byte 0x18 # DW_AT_decl_line + # DW_AT_prototyped + .long 0x63 # DW_AT_type + .quad .LFB1 # DW_AT_low_pc + .quad .LFE1 # DW_AT_high_pc + .uleb128 0x1 # DW_AT_frame_base + .byte 0x9c # DW_OP_call_frame_cfa + # DW_AT_GNU_all_tail_call_sites + .uleb128 0x4 # (DIE (0x63) DW_TAG_base_type) + .byte 0x4 # DW_AT_byte_size + .byte 0x5 # DW_AT_encoding + .ascii "int\0" # DW_AT_name + .byte 0 # end of children of DIE 0xb + .section .debug_abbrev,"",@progbits +.Ldebug_abbrev0: + .uleb128 0x1 # (abbrev code) + .uleb128 0x11 # (TAG: DW_TAG_compile_unit) + .byte 0x1 # DW_children_yes + .uleb128 0x25 # (DW_AT_producer) + .uleb128 0xe # (DW_FORM_strp) + .uleb128 0x13 # (DW_AT_language) + .uleb128 0xb # (DW_FORM_data1) + .uleb128 0x3 # (DW_AT_name) + .uleb128 0xe # (DW_FORM_strp) + .uleb128 0x1b # (DW_AT_comp_dir) + .uleb128 0xe # (DW_FORM_strp) + .uleb128 0x11 # (DW_AT_low_pc) + .uleb128 0x1 # (DW_FORM_addr) + .uleb128 0x12 # (DW_AT_high_pc) + .uleb128 0x1 # (DW_FORM_addr) + .uleb128 0x10 # (DW_AT_stmt_list) + .uleb128 0x17 # (DW_FORM_sec_offset) + .byte 0 + .byte 0 + .uleb128 0x2 # (abbrev code) + .uleb128 0x2e # (TAG: DW_TAG_subprogram) + .byte 0 # DW_children_no + .uleb128 0x3f # (DW_AT_external) + .uleb128 0x19 # (DW_FORM_flag_present) + .uleb128 0x3 # (DW_AT_name) + .uleb128 0xe # (DW_FORM_strp) + .uleb128 0x3a # (DW_AT_decl_file) + .uleb128 0xb # (DW_FORM_data1) + .uleb128 0x3b # (DW_AT_decl_line) + .uleb128 0xb # (DW_FORM_data1) + .uleb128 0x27 # (DW_AT_prototyped) + .uleb128 0x19 # (DW_FORM_flag_present) + .uleb128 0x11 # (DW_AT_low_pc) + .uleb128 0x1 # (DW_FORM_addr) + .uleb128 0x12 # (DW_AT_high_pc) + .uleb128 0x1 # (DW_FORM_addr) + .uleb128 0x40 # (DW_AT_frame_base) + .uleb128 0x18 # (DW_FORM_exprloc) + .uleb128 0x2117 # (DW_AT_GNU_all_call_sites) + .uleb128 0x19 # (DW_FORM_flag_present) + .byte 0 + .byte 0 + .uleb128 0x3 # (abbrev code) + .uleb128 0x2e # (TAG: DW_TAG_subprogram) + .byte 0 # DW_children_no + .uleb128 0x3f # (DW_AT_external) + .uleb128 0x19 # (DW_FORM_flag_present) + .uleb128 0x3 # (DW_AT_name) + .uleb128 0xe # (DW_FORM_strp) + .uleb128 0x3a # (DW_AT_decl_file) + .uleb128 0xb # (DW_FORM_data1) + .uleb128 0x3b # (DW_AT_decl_line) + .uleb128 0xb # (DW_FORM_data1) + .uleb128 0x27 # (DW_AT_prototyped) + .uleb128 0x19 # (DW_FORM_flag_present) + .uleb128 0x49 # (DW_AT_type) + .uleb128 0x13 # (DW_FORM_ref4) + .uleb128 0x11 # (DW_AT_low_pc) + .uleb128 0x1 # (DW_FORM_addr) + .uleb128 0x12 # (DW_AT_high_pc) + .uleb128 0x1 # (DW_FORM_addr) + .uleb128 0x40 # (DW_AT_frame_base) + .uleb128 0x18 # (DW_FORM_exprloc) + .uleb128 0x2116 # (DW_AT_GNU_all_tail_call_sites) + .uleb128 0x19 # (DW_FORM_flag_present) + .byte 0 + .byte 0 + .uleb128 0x4 # (abbrev code) + .uleb128 0x24 # (TAG: DW_TAG_base_type) + .byte 0 # DW_children_no + .uleb128 0xb # (DW_AT_byte_size) + .uleb128 0xb # (DW_FORM_data1) + .uleb128 0x3e # (DW_AT_encoding) + .uleb128 0xb # (DW_FORM_data1) + .uleb128 0x3 # (DW_AT_name) + .uleb128 0x8 # (DW_FORM_string) + .byte 0 + .byte 0 + .byte 0 + .section .debug_aranges,"",@progbits + .long 0x2c # Length of Address Ranges Info + .value 0x2 # DWARF Version + .long .Ldebug_info0 # Offset of Compilation Unit Info + .byte 0x8 # Size of Address + .byte 0 # Size of Segment Descriptor + .value 0 # Pad to 16 byte boundary + .value 0 + .quad .Ltext0 # Address + .quad .Letext0-.Ltext0 # Length + .quad 0 + .quad 0 + .section .debug_line,"",@progbits +.Ldebug_line0: + .section .debug_str,"MS",@progbits,1 +.LASF3: + .string "callee" +.LASF1: + .string "dw2-bad-cfi.c" +.LASF2: + .string "/home/tromey/gnu/gdb/devel/binutils-gdb/gdb/testsuite/gdb.dwarf2" +.LASF4: + .string "main" +.LASF0: + .string "GNU C 4.7.2 20121109 (Red Hat 4.7.2-8) -mtune=generic -march=x86-64 -g" + .ident "GCC: (GNU) 4.7.2 20121109 (Red Hat 4.7.2-8)" + .section .note.GNU-stack,"",@progbits diff --git a/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.c b/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.c new file mode 100644 index 0000000..f5b415b --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.c @@ -0,0 +1,28 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2013 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 . */ + +void +callee (void) +{ +} + +int +main(void) +{ + callee (); + return 0; +} diff --git a/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.exp b/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.exp new file mode 100644 index 0000000..12b1275 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/dw2-bad-cfi.exp @@ -0,0 +1,42 @@ +# Copyright 2013 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 . + +load_lib dwarf.exp + +standard_testfile .S + +# This test can only be run on targets which support DWARF-2 and use gas. +if ![dwarf2_support] { + return 0 +} + +# This test can only be run on x86-64 targets. +if {![istarget x86_64-*] || ![is_lp64_target]} { + return 0 +} + +if {[prepare_for_testing "$testfile.exp" "$testfile" $srcfile {nodebug}]} { + return -1 +} + +if ![runto_main] { + return -1 +} + +gdb_breakpoint "callee" +gdb_continue_to_breakpoint "callee" + +# This test ensures that the backtrace does not go past "callee". +gdb_test "bt" ".*callee .. at [file rootname $srcfile]\\.c:\[0-9\]*" -- 2.7.4