From e4ad960a577405c4d0f7593f439ad560fabc9d49 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Mon, 4 Jan 2021 19:34:25 +0100 Subject: [gdb/symtab] Remove superfluous end-of-sequence marker While working on PR26935 I noticed that when running test-case gdb.base/morestack.exp with target board unix/-m32/-fPIE/-pie and ld linker, I get this linetable fragment for morestack.S using readelf -wL: ... CU: ../../../../libgcc/config/i386/morestack.S: Line number Starting address View Stmt 109 0xc9c x ... 838 0xe03 x - 0xe04 636 0 x 637 0x3 x - 0x4 ... but with "maint info line-table" I get: ... INDEX LINE ADDRESS IS-STMT 0 END 0x00000004 Y 1 109 0x00000c9c Y ... 110 838 0x00000e03 Y 111 END 0x00000e04 Y ... So, apparently the entries with addresses 0x0 and 0x3 are filtered out because the addresses are out of range, but the same doesn't happen with the end-of-seq terminator. Fix this by filtering out end-of-seq terminators that do not actually terminate anything. Tested on x86_64-linux. gdb/ChangeLog: 2021-01-04 Tom de Vries * buildsym.c (buildsym_compunit::record_line): Filter out end-of-seq terminators that do not terminate anything. gdb/testsuite/ChangeLog: 2021-01-04 Tom de Vries * gdb.dwarf2/dw2-out-of-range-end-of-seq.exp: New file. --- gdb/ChangeLog | 5 ++ gdb/buildsym.c | 9 ++- gdb/testsuite/ChangeLog | 4 + .../gdb.dwarf2/dw2-out-of-range-end-of-seq.exp | 94 ++++++++++++++++++++++ 4 files changed, 110 insertions(+), 2 deletions(-) create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-out-of-range-end-of-seq.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 0d1c5a8..86a8b48 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2021-01-04 Tom de Vries + + * buildsym.c (buildsym_compunit::record_line): Filter out end-of-seq + terminators that do not terminate anything. + 2021-01-04 Simon Marchi * debug.c (debug_print_depth): New. diff --git a/gdb/buildsym.c b/gdb/buildsym.c index 1d8c579..0f7449f 100644 --- a/gdb/buildsym.c +++ b/gdb/buildsym.c @@ -707,13 +707,18 @@ buildsym_compunit::record_line (struct subfile *subfile, int line, anyway. */ if (line == 0) { + struct linetable_entry *last = nullptr; while (subfile->line_vector->nitems > 0) { - e = subfile->line_vector->item + subfile->line_vector->nitems - 1; - if (e->pc != pc) + last = subfile->line_vector->item + subfile->line_vector->nitems - 1; + if (last->pc != pc) break; subfile->line_vector->nitems--; } + + /* Ignore an end-of-sequence marker marking an empty sequence. */ + if (last == nullptr || last->line == 0) + return; } e = subfile->line_vector->item + subfile->line_vector->nitems++; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 9267579..2e47518 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2021-01-04 Tom de Vries + + * gdb.dwarf2/dw2-out-of-range-end-of-seq.exp: New file. + 2021-01-04 Simon Marchi diff --git a/gdb/testsuite/gdb.dwarf2/dw2-out-of-range-end-of-seq.exp b/gdb/testsuite/gdb.dwarf2/dw2-out-of-range-end-of-seq.exp new file mode 100644 index 0000000..7a32a01 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/dw2-out-of-range-end-of-seq.exp @@ -0,0 +1,94 @@ +# Copyright 2021 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 . + +# Check that an out-of-range DW_LNE_end_sequence is removed from the +# line table. + +load_lib dwarf.exp + +# This test can only be run on targets which support DWARF-2 and use gas. +if {![dwarf2_support]} { + verbose "Skipping $gdb_test_file_name." + return 0 +} + +# The .c files use __attribute__. +if [get_compiler_info] { + return -1 +} +if !$gcc_compiled { + verbose "Skipping $gdb_test_file_name." + return 0 +} + +standard_testfile main.c -dw.S + +set asm_file [standard_output_file $srcfile2] +Dwarf::assemble $asm_file { + declare_labels Llines + global srcdir subdir srcfile + + cu {} { + compile_unit { + {language @DW_LANG_C} + {name $srcfile} + {stmt_list $Llines DW_FORM_sec_offset} + } { + subprogram { + {external 1 flag} + {MACRO_AT_func {main}} + } + } + } + + lines {version 2} Llines { + include_dir "${srcdir}/${subdir}" + file_name "$srcfile" 1 + + program { + {DW_LNE_set_address main_label} + {line 1} + {DW_LNS_copy} + + {DW_LNS_advance_pc 1} + {DW_LNE_end_sequence} + + {DW_LNE_set_address 0} + {line 2} + {DW_LNS_copy} + + {DW_LNS_advance_pc 1} + {DW_LNE_end_sequence} + } + } +} + +if { [prepare_for_testing "failed to prepare" ${testfile} \ + [list $srcfile $asm_file] {nodebug}] } { + return -1 +} + +if ![runto_main] { + return -1 +} + +gdb_test_multiple "maint info line-table" "END with address 1 eliminated" { + -re -wrap "END *0x0*1 Y \r\n.*" { + fail $gdb_test_name + } + -re -wrap "" { + pass $gdb_test_name + } +} -- cgit v1.1