From FEDORA_PATCHES Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Fri, 23 Apr 2021 11:28:48 -0600 Subject: gdb-gdb27743-psymtab-imported-unit.patch ;; Backport "Fix crash when expanding partial symtabs with DW_TAG_imported_unit" ;; (Tom Tromey, gdb/27743) From e7d77ce0c408e7019f9885b8be64c9cdb46dd312 Mon Sep 17 00:00:00 2001 Subject: [PATCH] Fix crash when expanding partial symtabs with DW_TAG_imported_unit PR gdb/27743 points out a gdb crash when expanding partial symtabs, where one of the compilation units uses DW_TAG_imported_unit. The bug is that partial_map_expand_apply expects only to be called for the outermost psymtab. However, filename searching doesn't (and probably shouldn't) guarantee this. The fix is to walk upward to find the outermost CU. A new test case is included. It is mostly copied from other test cases, which really sped up the effort. This bug does not occur on trunk. There, psym_map_symtabs_matching_filename is gone, replaced by psymbol_functions::expand_symtabs_matching. When this find a match, it calls psymtab_to_symtab, which does this same upward walk. Tested on x86-64 Fedora 32. I propose checking in this patch on the gdb-10 branch, and just the new test case on trunk. gdb/ChangeLog 2021-04-23 Tom Tromey PR gdb/27743: * psymtab.c (partial_map_expand_apply): Expand outermost psymtab. gdb/testsuite/ChangeLog 2021-04-23 Tom Tromey PR gdb/27743: * gdb.dwarf2/imported-unit-bp.exp: New file. * gdb.dwarf2/imported-unit-bp-main.c: New file. * gdb.dwarf2/imported-unit-bp-alt.c: New file. diff --git a/gdb/psymtab.c b/gdb/psymtab.c --- a/gdb/psymtab.c +++ b/gdb/psymtab.c @@ -127,9 +127,10 @@ static struct compunit_symtab *psymtab_to_symtab (struct objfile *objfile, { struct compunit_symtab *last_made = objfile->compunit_symtabs; - /* Shared psymtabs should never be seen here. Instead they should - be handled properly by the caller. */ - gdb_assert (pst->user == NULL); + /* We may see a shared psymtab here, but we want to expand the + outermost symtab. */ + while (pst->user != nullptr) + pst = pst->user; /* Don't visit already-expanded psymtabs. */ if (pst->readin_p (objfile)) diff --git a/gdb/testsuite/gdb.dwarf2/imported-unit-bp-alt.c b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-alt.c new file mode 100644 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-alt.c @@ -0,0 +1,50 @@ +/* Copyright 2020-2021 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 . */ + +/* Used to insert labels with which we can build a fake line table. */ +#define LL(N) asm ("line_label_" #N ": .globl line_label_" #N) + +volatile int var; +volatile int bar; + +/* Generate some code to take up some space. */ +#define FILLER do { \ + var = 99; \ +} while (0) + +int +func (void) +{ /* func prologue */ + asm ("func_label: .globl func_label"); + LL (1); // F1, Ln 16 + FILLER; + LL (2); // F1, Ln 17 + FILLER; + LL (3); // F2, Ln 21 + FILLER; + LL (4); // F2, Ln 22 // F1, Ln 18, !S + FILLER; + LL (5); // F1, Ln 19 !S + FILLER; + LL (6); // F1, Ln 20 + FILLER; + LL (7); + FILLER; + return 0; /* func end */ +} + +#ifdef WITHMAIN +int main () { return 0; } +#endif diff --git a/gdb/testsuite/gdb.dwarf2/imported-unit-bp-main.c b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-main.c new file mode 100644 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-main.c @@ -0,0 +1,24 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2004-2021 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 . */ + +extern int func (void); + +int +main() +{ + return func (); +} diff --git a/gdb/testsuite/gdb.dwarf2/imported-unit-bp.exp b/gdb/testsuite/gdb.dwarf2/imported-unit-bp.exp new file mode 100644 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/imported-unit-bp.exp @@ -0,0 +1,128 @@ +# Copyright 2020-2021 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 . + +# Test that "break /absolute/file:line" works ok with imported CUs. + +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 +} + +standard_testfile imported-unit-bp-alt.c .S imported-unit-bp-main.c + +set build_options {nodebug optimize=-O1} + +set asm_file [standard_output_file $srcfile2] +Dwarf::assemble $asm_file { + global srcdir subdir srcfile srcfile + global build_options + declare_labels lines_label callee_subprog_label cu_label + + get_func_info func "$build_options additional_flags=-DWITHMAIN" + + cu {} { + compile_unit { + {language @DW_LANG_C} + {name ""} + } { + imported_unit { + {import %$cu_label} + } + } + } + + cu {} { + cu_label: compile_unit { + {producer "gcc"} + {language @DW_LANG_C} + {name ${srcfile}} + {comp_dir "/tmp"} + {low_pc 0 addr} + {stmt_list ${lines_label} DW_FORM_sec_offset} + } { + callee_subprog_label: subprogram { + {external 1 flag} + {name callee} + {inline 3 data1} + } + subprogram { + {external 1 flag} + {name func} + {low_pc $func_start addr} + {high_pc "$func_start + $func_len" addr} + } { + } + } + } + + lines {version 2 default_is_stmt 1} lines_label { + include_dir "/tmp" + file_name "$srcfile" 1 + + program { + {DW_LNE_set_address line_label_1} + {DW_LNS_advance_line 15} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_2} + {DW_LNS_advance_line 1} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_3} + {DW_LNS_advance_line 4} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_4} + {DW_LNS_advance_line 1} + {DW_LNS_copy} + + {DW_LNS_advance_line -4} + {DW_LNS_negate_stmt} + {DW_LNS_copy} + + {DW_LNE_set_address line_label_5} + {DW_LNS_advance_line 1} + {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 line_label_7} + {DW_LNE_end_sequence} + } + } +} + +if { [prepare_for_testing "failed to prepare" ${testfile} \ + [list $srcfile $asm_file $srcfile3] $build_options] } { + return -1 +} + +gdb_reinitialize_dir /tmp + +# Using an absolute path is important to see the bug. +gdb_test "break /tmp/${srcfile}:19" "Breakpoint .* file $srcfile, line .*"