From 3bd0f5c4d9924be476bdcf6a3d77d7b212d22523 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Wed, 4 Sep 2024 10:07:19 +0200 Subject: [PATCH] [gdb/testsuite] Fix gdb.dwarf2/dw2-lines.exp on arm-linux With test-case gdb.dwarf2/dw2-lines.exp on arm-linux, I run into: ... (gdb) break bar_label^M Breakpoint 2 at 0x4004f6: file dw2-lines.c, line 29.^M (gdb) continue^M Continuing.^M ^M Breakpoint 2, bar () at dw2-lines.c:29^M 29 foo (2);^M (gdb) PASS: $exp: cv=2: cdw=32: lv=2: ldw=32: continue to breakpoint: foo \(1\) ... The pass is incorrect because the continue lands at line 29 with "foo (2)" instead of line line 27 with "foo (1)". A minimal version is: ... $ gdb -q -batch dw2-lines.cv-2-cdw-32-lv-2-ldw-32 -ex "b bar_label" Breakpoint 1 at 0x4f6: file dw2-lines.c, line 29. ... where: ... 000004ec : 4ec: b580 push {r7, lr} 4ee: af00 add r7, sp, #0 000004f0 : 4f0: 2001 movs r0, #1 4f2: f7ff fff1 bl 4d8 000004f6 : 4f6: 2002 movs r0, #2 4f8: f7ff ffee bl 4d8 ... So, how does this happen? In short: - skip_prologue_sal calls arm_skip_prologue with pc == 0x4ec, - thumb_analyze_prologue returns 0x4f2 (overshooting by 1 insn, PR tdep/31981), and - skip_prologue_sal decides that we're mid-line, and updates to 0x4f6. However, this is a test-case about .debug_line info, so why didn't arm_skip_prologue use the line info to skip the prologue? The answer is that the line info starts at bar_label, not at bar. Fixing that allows us to work around PR tdep/31981. Likewise in gdb.dwarf2/dw2-line-number-zero.exp. Instead, add a new test-case gdb.arch/skip-prologue.exp that is dedicated to checking quality of architecture-specific prologue analysis, without being written in an architecture-specific way. If fails on arm-linux for both marm and mthumb: ... FAIL: gdb.arch/skip-prologue.exp: f2: $bp_addr == $prologue_end_addr (skipped too much) FAIL: gdb.arch/skip-prologue.exp: f4: $bp_addr == $prologue_end_addr (skipped too much) ... and passes for: - x86_64-linux for {m64,m32}x{-fno-PIE/-no-pie,-fPIE/-pie} - aarch64-linux. Tested on arm-linux. --- gdb/testsuite/gdb.arch/skip-prologue.c | 54 +++++++++++++ gdb/testsuite/gdb.arch/skip-prologue.exp | 76 +++++++++++++++++++ .../gdb.dwarf2/dw2-line-number-zero.exp | 8 ++ gdb/testsuite/gdb.dwarf2/dw2-lines.c | 2 +- gdb/testsuite/gdb.dwarf2/dw2-lines.exp | 4 + 5 files changed, 143 insertions(+), 1 deletion(-) create mode 100644 gdb/testsuite/gdb.arch/skip-prologue.c create mode 100644 gdb/testsuite/gdb.arch/skip-prologue.exp diff --git a/gdb/testsuite/gdb.arch/skip-prologue.c b/gdb/testsuite/gdb.arch/skip-prologue.c new file mode 100644 index 00000000000..08ceacb6aa8 --- /dev/null +++ b/gdb/testsuite/gdb.arch/skip-prologue.c @@ -0,0 +1,54 @@ +/* Copyright 2024 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 . */ + +void +f1 (void) +{ + asm ("f1_prologue_end: .globl f1_prologue_end"); +} + +int +f2 (int a) +{ + asm ("f2_prologue_end: .globl f2_prologue_end"); + return a; +} + +void +f3 (void) +{ + asm ("f3_prologue_end: .globl f3_prologue_end"); + f1 (); +} + +int +f4 (int a) +{ + asm ("f4_prologue_end: .globl f4_prologue_end"); + return f2 (a); +} + +int +main (void) +{ + f1 (); + f2 (0); + f3 (); + f4 (0); + + return 0; +} diff --git a/gdb/testsuite/gdb.arch/skip-prologue.exp b/gdb/testsuite/gdb.arch/skip-prologue.exp new file mode 100644 index 00000000000..89d2225151a --- /dev/null +++ b/gdb/testsuite/gdb.arch/skip-prologue.exp @@ -0,0 +1,76 @@ +# Copyright 2024 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 . + +# Test-case that checks architecture-specific prologue analyzers. + +standard_testfile + +if { [prepare_for_testing "failed to prepare" $testfile $srcfile \ + {nodebug}] } { + return -1 +} + +proc do_test { f } { + set bp_addr "" + gdb_test_multiple "break $f" "" { + -re -wrap "Breakpoint $::decimal at ($::hex)" { + set bp_addr $expect_out(1,string) + pass $gdb_test_name + } + } + + if { $bp_addr == "" } { + return + } + + set prologue_end_addr "" + gdb_test_multiple "p /x &${f}_prologue_end" "" { + -re -wrap " = ($::hex)" { + set prologue_end_addr $expect_out(1,string) + pass $gdb_test_name + } + } + + if { $prologue_end_addr == "" } { + return + } + + set test {$bp_addr == $prologue_end_addr} + if { [expr $test] } { + pass $test + } elseif { $bp_addr < $prologue_end_addr } { + # We'll allow this. For instance, amd64 has a prologue + # analyzer that doesn't skip the 3rd instruction here, which saves an + # argument register to stack: + # + # 00000000004004ae : + # 4004ae: 55 push %rbp + # 4004af: 48 89 e5 mov %rsp,%rbp + # 4004b2: 89 7d fc mov %edi,-0x4(%rbp) + # 00000000004004b5 : + # + pass "$test (skipped less than possible)" + } elseif { $bp_addr > $prologue_end_addr } { + fail "$test (skipped too much)" + } else { + fail "$test" + } +} + +foreach f { f1 f2 f3 f4 } { + with_test_prefix $f { + do_test $f + } +} diff --git a/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp b/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp index c510de42037..9124aff1dad 100644 --- a/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp +++ b/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp @@ -56,6 +56,10 @@ Dwarf::assemble $asm_file { file_name "$srcfile" 1 program { + DW_LNE_set_address $bar1_start + line 25 + DW_LNS_copy + DW_LNE_set_address bar1_label line 27 DW_LNS_copy @@ -76,6 +80,10 @@ Dwarf::assemble $asm_file { DW_LNE_end_sequence + DW_LNE_set_address $bar2_start + line 39 + DW_LNS_copy + DW_LNE_set_address bar2_label line 41 DW_LNS_copy diff --git a/gdb/testsuite/gdb.dwarf2/dw2-lines.c b/gdb/testsuite/gdb.dwarf2/dw2-lines.c index 67c98fecf02..221d7b95bc3 100644 --- a/gdb/testsuite/gdb.dwarf2/dw2-lines.c +++ b/gdb/testsuite/gdb.dwarf2/dw2-lines.c @@ -22,7 +22,7 @@ foo (int x) void bar (void) -{ +{ /* bar: */ asm ("bar_label: .globl bar_label"); foo (1); asm ("bar_label_2: .globl bar_label_2"); diff --git a/gdb/testsuite/gdb.dwarf2/dw2-lines.exp b/gdb/testsuite/gdb.dwarf2/dw2-lines.exp index 9617782749b..4814f493a76 100644 --- a/gdb/testsuite/gdb.dwarf2/dw2-lines.exp +++ b/gdb/testsuite/gdb.dwarf2/dw2-lines.exp @@ -88,6 +88,10 @@ proc test_1 { _cv _cdw64 _lv _ldw64 {_string_form ""}} { # to set the current file explicitly. DW_LNS_set_file $diridx + DW_LNE_set_address $bar_start + line [line_for bar] + DW_LNS_copy + DW_LNE_set_address bar_label line [line_for bar_label] DW_LNS_copy