From 137c886e9a624f68cba212ebdb156298957c25c4 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Fri, 30 Sep 2022 05:47:54 +0200 Subject: [PATCH] [gdb/c++] Print destructor the same for gcc and clang Consider the test-case contained in this patch. With g++ (7.5.0) we have for "ptype A": ... type = class A { public: int a; A(void); ~A(); } ... and with clang++ (13.0.1): ... type = class A { public: int a; A(void); ~A(void); } ... and we observe that the destructor is printed differently. There's a difference in debug info between the two cases: in the clang case, there's one artificial parameter, but in the g++ case, there are two, and these similar cases are handled differently in cp_type_print_method_args. This is due to this slightly convoluted bit of code: ... i = staticp ? 0 : 1; if (nargs > i) { while (i < nargs) ... } else if (varargs) gdb_printf (stream, "..."); else if (language == language_cplus) gdb_printf (stream, "void"); ... The purpose of "i = staticp ? 0 : 1" is to skip the printing of the implicit this parameter. In commit 5f4d1085085 ("c++/8218: Destructors w/arguments"), skipping of other artificial parameters was added, but using a different method: rather than adjusting the potential loop start, it skips the parameter in the loop. The observed difference in printing is explained by whether we enter the loop: - in the clang case, the loop is not entered and we print "void". - in the gcc case, the loop is entered, and nothing is printed. Fix this by rewriting the code to: - always enter the loop - handle whether arguments need printing in the loop - keep track of how many arguments are printed, and use that after the loop to print void etc. such that we have the same for both gcc and clang: ... A(void); ~A(void); ... Note that I consider the discussion of whether we want to print: - A(void) / ~A(void), or - A() / ~A() out-of-scope for this patch. Tested on x86_64-linux. --- gdb/c-typeprint.c | 59 +++++++++++++--------- gdb/testsuite/gdb.base/ptype-offsets.exp | 2 +- gdb/testsuite/gdb.cp/print-method-args.cc | 38 ++++++++++++++ gdb/testsuite/gdb.cp/print-method-args.exp | 38 ++++++++++++++ gdb/testsuite/gdb.cp/templates.exp | 4 +- 5 files changed, 113 insertions(+), 28 deletions(-) create mode 100644 gdb/testsuite/gdb.cp/print-method-args.cc create mode 100644 gdb/testsuite/gdb.cp/print-method-args.exp diff --git a/gdb/c-typeprint.c b/gdb/c-typeprint.c index 3a611cdac5d..23e8a5a4d6f 100644 --- a/gdb/c-typeprint.c +++ b/gdb/c-typeprint.c @@ -273,35 +273,44 @@ cp_type_print_method_args (struct type *mtype, const char *prefix, language_cplus, DMGL_ANSI); gdb_puts ("(", stream); - /* Skip the class variable. We keep this here to accommodate older - compilers and debug formats which may not support artificial - parameters. */ - i = staticp ? 0 : 1; - if (nargs > i) + int printed_args = 0; + for (i = 0; i < nargs; ++i) { - while (i < nargs) + if (i == 0 && !staticp) { - struct field arg = args[i++]; - - /* Skip any artificial arguments. */ - if (FIELD_ARTIFICIAL (arg)) - continue; - - c_print_type (arg.type (), "", stream, 0, 0, language, flags); - - if (i == nargs && varargs) - gdb_printf (stream, ", ..."); - else if (i < nargs) - { - gdb_printf (stream, ", "); - stream->wrap_here (8); - } + /* Skip the class variable. We keep this here to accommodate older + compilers and debug formats which may not support artificial + parameters. */ + continue; } + + struct field arg = args[i]; + /* Skip any artificial arguments. */ + if (FIELD_ARTIFICIAL (arg)) + continue; + + if (printed_args > 0) + { + gdb_printf (stream, ", "); + stream->wrap_here (8); + } + + c_print_type (arg.type (), "", stream, 0, 0, language, flags); + printed_args++; + } + + if (varargs) + { + if (printed_args == 0) + gdb_printf (stream, "..."); + else + gdb_printf (stream, ", ..."); + } + else if (printed_args == 0) + { + if (language == language_cplus) + gdb_printf (stream, "void"); } - else if (varargs) - gdb_printf (stream, "..."); - else if (language == language_cplus) - gdb_printf (stream, "void"); gdb_printf (stream, ")"); diff --git a/gdb/testsuite/gdb.base/ptype-offsets.exp b/gdb/testsuite/gdb.base/ptype-offsets.exp index e80d876fa32..eb41bafb3e6 100644 --- a/gdb/testsuite/gdb.base/ptype-offsets.exp +++ b/gdb/testsuite/gdb.base/ptype-offsets.exp @@ -104,7 +104,7 @@ gdb_test "ptype /oTM struct abc" \ "/* 48 | 2 */ my_int_type field9;" \ "" \ " abc(void);" \ -" ~abc();" \ +" ~abc(void);" \ "" \ " typedef short my_int_type;" \ "/* XXX 6-byte padding */" \ diff --git a/gdb/testsuite/gdb.cp/print-method-args.cc b/gdb/testsuite/gdb.cp/print-method-args.cc new file mode 100644 index 00000000000..98be8286aeb --- /dev/null +++ b/gdb/testsuite/gdb.cp/print-method-args.cc @@ -0,0 +1,38 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright (C) 2022 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 . */ + +class A { +public: + int a; + + A() { + this->a = 3; + } + ~A() { + a = 0; + } +}; + +int +main (void) +{ + A a; + + return a.a; +} diff --git a/gdb/testsuite/gdb.cp/print-method-args.exp b/gdb/testsuite/gdb.cp/print-method-args.exp new file mode 100644 index 00000000000..7773e041e21 --- /dev/null +++ b/gdb/testsuite/gdb.cp/print-method-args.exp @@ -0,0 +1,38 @@ +# Copyright (C) 2022 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 . + +# This file is part of the gdb testsuite. + +# This test checks that a constructor and destructor are printed the same. + +if { [skip_cplus_tests] } { continue } + +standard_testfile .cc + +if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug c++}]} { + return -1 +} + +set re \ + [multi_line \ + "type = class A {" \ + " public:" \ + " int a;" \ + "" \ + " A\\(void\\);" \ + " ~A\\(void\\);" \ + "}"] + +gdb_test "ptype A" $re diff --git a/gdb/testsuite/gdb.cp/templates.exp b/gdb/testsuite/gdb.cp/templates.exp index 27c9bbc1c7e..d3ede5a5fb6 100644 --- a/gdb/testsuite/gdb.cp/templates.exp +++ b/gdb/testsuite/gdb.cp/templates.exp @@ -68,7 +68,7 @@ proc test_ptype_of_templates {} { # The destructor has an argument type. kfail "gdb/8218" "ptype T5" } - -re "type = class T5 \{${ws}public:${ws}static int X;${ws}int x;${ws}int val;${ws}T5\\(int\\);${ws}T5\\((T5 const|const T5) ?&\\);${ws}~T5\\(\\);${ws}static void \\* operator new\\((size_t|unsigned( int| long|))\\);${ws}static void operator delete\\(void ?\\*\\);${ws}int value\\((void|)\\);${ws}\}\r\n$gdb_prompt $" { + -re "type = class T5 \{${ws}public:${ws}static int X;${ws}int x;${ws}int val;${ws}T5\\(int\\);${ws}T5\\((T5 const|const T5) ?&\\);${ws}~T5\\(void\\);${ws}static void \\* operator new\\((size_t|unsigned( int| long|))\\);${ws}static void operator delete\\(void ?\\*\\);${ws}int value\\((void|)\\);${ws}\}\r\n$gdb_prompt $" { pass "ptype T5" } } @@ -108,7 +108,7 @@ proc test_ptype_of_templates {} { # The destructor has an argument type. kfail "gdb/8218" "ptype t5i" } - -re "type = class T5 \{${ws}public:${ws}static int X;${ws}int x;${ws}int val;${ws}T5\\(int\\);${ws}T5\\((T5 const|const T5) ?&\\);${ws}~T5\\(\\);${ws}static void \\* operator new\\((size_t|unsigned( int| long|))\\);${ws}static void operator delete\\(void ?\\*\\);${ws}int value\\((void|)\\);${ws}\}\r\n$gdb_prompt $" { + -re "type = class T5 \{${ws}public:${ws}static int X;${ws}int x;${ws}int val;${ws}T5\\(int\\);${ws}T5\\((T5 const|const T5) ?&\\);${ws}~T5\\(void\\);${ws}static void \\* operator new\\((size_t|unsigned( int| long|))\\);${ws}static void operator delete\\(void ?\\*\\);${ws}int value\\((void|)\\);${ws}\}\r\n$gdb_prompt $" { pass "ptype t5i" } }