From 78344df7b5d7d7fcf6aa7945b8c4b56bcc9388ce Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Tue, 21 Jul 2020 11:21:50 +0100 Subject: [PATCH] gdb/disassembly: Update to handle non-statement addresses After the introduction of support for non-statement addresses in the line table, the output for 'disassemble /m' can be broken in some cases. With the /m format disassembly GDB associates a set of addresses with each line, these addresses are then sorted and printed for each line. When the non-statement support was added GDB was incorrectly told to ignore non-statement instructions, and not add these to the result table. This means that these instructions are completely missing from the output. This commit removes the code that caused non-statement lines to be ignored. A result of this change is that GDB will now potentially include new line numbers in the 'disassemble /m' output, lines that previously were only in the line table as non-statement lines will now appear in the disassembly output. This feels like an improvement though. gdb/ChangeLog: * disasm.c (do_mixed_source_and_assembly_deprecated): Don't exclude non-statement entries. gdb/testsuite/ChangeLog: * gdb.dwarf2/dw2-disasm-over-non-stmt.exp: New file. --- gdb/ChangeLog | 5 + gdb/disasm.c | 6 - gdb/testsuite/ChangeLog | 4 + .../gdb.dwarf2/dw2-disasm-over-non-stmt.exp | 206 ++++++++++++++++++ 4 files changed, 215 insertions(+), 6 deletions(-) create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-disasm-over-non-stmt.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 7ba156188a6..c400d234f5f 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2020-07-23 Andrew Burgess + + * disasm.c (do_mixed_source_and_assembly_deprecated): Don't + exclude non-statement entries. + 2020-07-22 Kevin Buettner * NEWS (New commands): Mention new command diff --git a/gdb/disasm.c b/gdb/disasm.c index 143ba2f59b9..e45c8400689 100644 --- a/gdb/disasm.c +++ b/gdb/disasm.c @@ -376,12 +376,6 @@ do_mixed_source_and_assembly_deprecated if (le[i].line == le[i + 1].line && le[i].pc == le[i + 1].pc) continue; /* Ignore duplicates. */ - /* Ignore non-statement line table entries. This means we print the - source line at the place where GDB would insert a breakpoint for - that line, which seems more intuitive. */ - if (le[i].is_stmt == 0) - continue; - /* Skip any end-of-function markers. */ if (le[i].line == 0) continue; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 06bafcebc9d..c9502eeedf7 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2020-07-23 Andrew Burgess + + * gdb.dwarf2/dw2-disasm-over-non-stmt.exp: New file. + 2020-07-22 Sandra Loosemore * lib/gdb.exp (gdb_wrapper_file, gdb_wrapper_flags): diff --git a/gdb/testsuite/gdb.dwarf2/dw2-disasm-over-non-stmt.exp b/gdb/testsuite/gdb.dwarf2/dw2-disasm-over-non-stmt.exp new file mode 100644 index 00000000000..6df275f1b11 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/dw2-disasm-over-non-stmt.exp @@ -0,0 +1,206 @@ +# Copyright 2020 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 . + +# Create an example function that contains both addresses marked as +# statements and addresses marked as non-statements, and then +# disassemble the function. +# +# Of particular interest is how 'disassemble /m' handles the +# non-statement addresses, we want to ensure that these addresses are +# included in the disassembly output. For completeness we test both +# 'disassemble /m' and 'disassemble /s'. + +load_lib dwarf.exp + +# This test can only be run on targets which support DWARF-2 and use gas. +if {![dwarf2_support]} { + return 0 +} + +# The .c files use __attribute__. +if [get_compiler_info] { + return -1 +} +if !$gcc_compiled { + return 0 +} + +# Reuse many of the test source files from dw2-inline-header-1.exp. +standard_testfile dw2-inline-header-lbls.c dw2-inline-header.S \ + dw2-inline-header.c + +set asm_file [standard_output_file $srcfile2] +Dwarf::assemble $asm_file { + global srcdir subdir srcfile srcfile3 + declare_labels lines_label + + get_func_info main + + cu {} { + compile_unit { + {producer "gcc" } + {language @DW_LANG_C} + {name ${srcfile3}} + {low_pc 0 addr} + {stmt_list ${lines_label} DW_FORM_sec_offset} + } { + subprogram { + {external 1 flag} + {MACRO_AT_func {main}} + } + } + } + + lines {version 2 default_is_stmt 1} lines_label { + include_dir "${srcdir}/${subdir}" + file_name "$srcfile3" 1 + + program { + {DW_LNE_set_address $main_start} + {DW_LNS_advance_line 15} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_2} + {DW_LNS_negate_stmt} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_3} + {DW_LNS_advance_line 1} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_4} + {DW_LNS_negate_stmt} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_5} + {DW_LNS_negate_stmt} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_6} + {DW_LNS_advance_line 1} + {DW_LNS_negate_stmt} + {DW_LNS_copy} + + {DW_LNE_set_address $main_end} + {DW_LNS_copy} + {DW_LNE_end_sequence} + } + } +} + +if { [prepare_for_testing "failed to prepare" ${testfile} \ + [list $srcfile $asm_file] {nodebug} ] } { + return -1 +} + +if ![runto_main] { + return -1 +} + +# Global lines array, maps lines numbers to the list of addresses +# associated with that line in the debug output. +array set lines {} + +# Look in the global LINES array and check that the disassembly for +# line LINENUM includes the address of LABEL. +proc check_disassembly_results { linenum label } { + global lines + + set address [get_hexadecimal_valueof "&${label}" "__unknown__"] + set testname "check_disassembly_results $linenum $label" + if {![info exists lines($linenum)]} { + fail "$testname (no disassembly for $linenum)" + return + } + + # Use a loop to compare the addresses as the addresses extracted + # from the disassembly output can be padded with zeros, while the + # address of the label will not be padded. + set addrs $lines($linenum) + foreach a $addrs { + if { $a == $address } { + pass $testname + return + } + } + fail $testname +} + +foreach_with_prefix opt { m s } { + # Disassemble 'main' and split up the disassembly output. We + # build an associative array, for each line number store the list + # of addresses that were part of its disassembly output. + # + # LINENUM is the line we are currently collecting the disassembly + # addresses for, and ADDRS is the list of addresses collected for + # this line. + set linenum -1 + set addrs {} + + # Clear the global associative array used to hold the results. + unset lines + array set lines {} + + gdb_test_multiple "disassemble /${opt} main" "" { + -re "Dump of assembler code for function main:\r\n" { + exp_continue + } + + -re "^\[^\r\n\]+${srcfile3}:" { + exp_continue + } + + -re "^(\\d+)\\s+\[^\r\n\]+\r\n" { + if { $linenum != -1 } { + set lines($linenum) $addrs + set addrs {} + } + set linenum $expect_out(1,string) + exp_continue + } + + -re "^(?:=>)?\\s*($hex)\\s*\[^\r\n\]+\r\n" { + set address $expect_out(1,string) + lappend addrs $address + exp_continue + } + + -re "^\\s*\r\n" { + exp_continue + } + + -re "^End of assembler dump\\.\r\n" { + if { $linenum != -1 } { + set lines($linenum) $addrs + set linenum -1 + set addrs {} + } + exp_continue + } + + -re "^$gdb_prompt $" { + # All done. + } + } + + # Now check that each label we expect to be associated with each line + # shows up in the disassembly output. + check_disassembly_results 16 "line_label_1" + check_disassembly_results 16 "line_label_2" + check_disassembly_results 17 "line_label_3" + check_disassembly_results 17 "line_label_4" + check_disassembly_results 17 "line_label_5" + check_disassembly_results 18 "line_label_6" +} -- 2.30.2