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Handle alignof and _Alignof

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This adds alignof and _Alignof to the C/C++ expression parser, and
adds new tests to test the features.  The tests are written to try to
ensure that gdb's knowledge of alignment rules stays in sync with the
compiler's.

2018-04-30  Tom Tromey  <tom@tromey.com>

	PR exp/17095:
	* NEWS: Update.
	* std-operator.def (UNOP_ALIGNOF): New operator.
	* expprint.c (dump_subexp_body_standard) <case UNOP_ALIGNOF>:
	New.
	* eval.c (evaluate_subexp_standard) <case UNOP_ALIGNOF>: New.
	* c-lang.c (c_op_print_tab): Add alignof.
	* c-exp.y (ALIGNOF): New token.
	(exp): Add "ALIGNOF" production.
	(ident_tokens): Add _Alignof and alignof.

2018-04-30  Tom Tromey  <tom@tromey.com>

	PR exp/17095:
	* gdb.dwarf2/dw2-align.exp: New file.
	* gdb.cp/align.exp: New file.
	* gdb.base/align.exp: New file.
	* lib/gdb.exp (gdb_int128_helper): New proc.
	(has_int128_c, has_int128_cxx): New caching procs.
This commit is contained in:
Tom Tromey 2018-04-20 13:40:29 -06:00
parent 2b4424c35b
commit 007e153034
12 changed files with 444 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
gdb/ChangeLog
View File

@ -1,3 +1,16 @@
2018-04-30 Tom Tromey <tom@tromey.com>
PR exp/17095:
* NEWS: Update.
* std-operator.def (UNOP_ALIGNOF): New operator.
* expprint.c (dump_subexp_body_standard) <case UNOP_ALIGNOF>:
New.
* eval.c (evaluate_subexp_standard) <case UNOP_ALIGNOF>: New.
* c-lang.c (c_op_print_tab): Add alignof.
* c-exp.y (ALIGNOF): New token.
(exp): Add "ALIGNOF" production.
(ident_tokens): Add _Alignof and alignof.
2018-04-30 Tom Tromey <tom@tromey.com>
* i386-tdep.c (i386_type_align): New function.

3
gdb/NEWS
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@ -9,6 +9,9 @@
* 'info proc' now works on running processes on FreeBSD systems and core
files created on FreeBSD systems.
* C expressions can now use _Alignof, and C++ expressions can now use
alignof.
* New commands
set debug fbsd-nat

8
gdb/c-exp.y
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@ -173,7 +173,7 @@ static void c_print_token (FILE *file, int type, YYSTYPE value);
%token <ssym> NAME_OR_INT
%token OPERATOR
%token STRUCT CLASS UNION ENUM SIZEOF UNSIGNED COLONCOLON
%token STRUCT CLASS UNION ENUM SIZEOF ALIGNOF UNSIGNED COLONCOLON
%token TEMPLATE
%token ERROR
%token NEW DELETE
@ -307,6 +307,10 @@ exp : SIZEOF exp %prec UNARY
{ write_exp_elt_opcode (pstate, UNOP_SIZEOF); }
;
exp : ALIGNOF '(' type_exp ')' %prec UNARY
{ write_exp_elt_opcode (pstate, UNOP_ALIGNOF); }
;
exp : exp ARROW name
{ write_exp_elt_opcode (pstate, STRUCTOP_PTR);
write_exp_string (pstate, $3);
@ -2329,6 +2333,8 @@ static const struct token ident_tokens[] =
{"struct", STRUCT, OP_NULL, 0},
{"signed", SIGNED_KEYWORD, OP_NULL, 0},
{"sizeof", SIZEOF, OP_NULL, 0},
{"_Alignof", ALIGNOF, OP_NULL, 0},
{"alignof", ALIGNOF, OP_NULL, FLAG_CXX},
{"double", DOUBLE_KEYWORD, OP_NULL, 0},
{"false", FALSEKEYWORD, OP_NULL, FLAG_CXX},
{"class", CLASS, OP_NULL, FLAG_CXX},

1
gdb/c-lang.c
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@ -751,6 +751,7 @@ const struct op_print c_op_print_tab[] =
{"*", UNOP_IND, PREC_PREFIX, 0},
{"&", UNOP_ADDR, PREC_PREFIX, 0},
{"sizeof ", UNOP_SIZEOF, PREC_PREFIX, 0},
{"alignof ", UNOP_ALIGNOF, PREC_PREFIX, 0},
{"++", UNOP_PREINCREMENT, PREC_PREFIX, 0},
{"--", UNOP_PREDECREMENT, PREC_PREFIX, 0},
{NULL, OP_NULL, PREC_PREFIX, 0}

13
gdb/eval.c
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@ -2667,6 +2667,19 @@ evaluate_subexp_standard (struct type *expect_type,
}
return evaluate_subexp_for_sizeof (exp, pos, noside);
case UNOP_ALIGNOF:
{
struct type *type
= value_type (evaluate_subexp (NULL_TYPE, exp, pos,
EVAL_AVOID_SIDE_EFFECTS));
/* FIXME: This should be size_t. */
struct type *size_type = builtin_type (exp->gdbarch)->builtin_int;
ULONGEST align = type_align (type);
if (align == 0)
error (_("could not determine alignment of type"));
return value_from_longest (size_type, align);
}
case UNOP_CAST:
(*pos) += 2;
type = exp->elts[pc + 1].type;

1
gdb/expprint.c
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@ -850,6 +850,7 @@ dump_subexp_body_standard (struct expression *exp,
case UNOP_PREDECREMENT:
case UNOP_POSTDECREMENT:
case UNOP_SIZEOF:
case UNOP_ALIGNOF:
case UNOP_PLUS:
case UNOP_CAP:
case UNOP_CHR:

1
gdb/std-operator.def
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@ -234,6 +234,7 @@ OP (UNOP_POSTINCREMENT) /* ++ after an expression */
OP (UNOP_PREDECREMENT) /* -- before an expression */
OP (UNOP_POSTDECREMENT) /* -- after an expression */
OP (UNOP_SIZEOF) /* Unary sizeof (followed by expression) */
OP (UNOP_ALIGNOF) /* Unary alignof (followed by expression) */
OP (UNOP_PLUS) /* Unary plus */

9
gdb/testsuite/ChangeLog
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@ -1,3 +1,12 @@
2018-04-30 Tom Tromey <tom@tromey.com>
PR exp/17095:
* gdb.dwarf2/dw2-align.exp: New file.
* gdb.cp/align.exp: New file.
* gdb.base/align.exp: New file.
* lib/gdb.exp (gdb_int128_helper): New proc.
(has_int128_c, has_int128_cxx): New caching procs.
2018-04-27 Tom Tromey <tom@tromey.com>
PR rust/22545:

109
gdb/testsuite/gdb.base/align.exp Normal file
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@ -0,0 +1,109 @@
# Copyright 2018 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 <http://www.gnu.org/licenses/>.
# This file is part of the gdb testsuite
# This tests that C11 _Alignof works in gdb, and that it agrees with
# the compiler.
# The types we're going to test.
set typelist {
char {unsigned char}
short {unsigned short}
int {unsigned int}
long {unsigned long}
{long long} {unsigned long long}
float
double {long double}
}
if {[has_int128_c]} {
# Note we don't check "unsigned __int128" yet because at least gcc
# canonicalizes the name to "__int128 unsigned", and there isn't a
# c-exp.y production for this.
# https://sourceware.org/bugzilla/show_bug.cgi?id=20991
lappend typelist __int128
}
# Create the test file.
set filename [standard_output_file align.c]
set outfile [open $filename w]
# Prologue.
puts -nonewline $outfile "#define DEF(T,U) struct align_pair_ ## T ## _x_ ## U "
puts $outfile "{ T one; U two; }"
puts $outfile "unsigned a_void = _Alignof(void);"
# First emit single items.
foreach type $typelist {
set utype [join [split $type] _]
if {$type != $utype} {
puts $outfile "typedef $type $utype;"
}
puts $outfile "$type item_$utype;"
puts $outfile "unsigned a_$utype\n = _Alignof ($type);"
set utype [join [split $type] _]
}
# Now emit all pairs.
foreach type $typelist {
set utype [join [split $type] _]
foreach inner $typelist {
set uinner [join [split $inner] _]
puts $outfile "DEF ($utype, $uinner);"
set joined "${utype}_x_${uinner}"
puts $outfile "struct align_pair_$joined item_${joined};"
puts $outfile "unsigned a_${joined}"
puts $outfile " = _Alignof (struct align_pair_${joined});"
}
}
# Epilogue.
puts $outfile {
int main() {
return 0;
}
}
close $outfile
standard_testfile $filename
if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug}]} {
return -1
}
if {![runto_main]} {
perror "test suppressed"
return
}
foreach type $typelist {
set utype [join [split $type] _]
set expected [get_integer_valueof a_$utype 0]
gdb_test "print _Alignof($type)" " = $expected"
foreach inner $typelist {
set uinner [join [split $inner] _]
set expected [get_integer_valueof a_${utype}_x_${uinner} 0]
gdb_test "print _Alignof(struct align_pair_${utype}_x_${uinner})" \
" = $expected"
}
}
set expected [get_integer_valueof a_void 0]
gdb_test "print _Alignof(void)" " = $expected"

174
gdb/testsuite/gdb.cp/align.exp Normal file
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@ -0,0 +1,174 @@
# Copyright 2018 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 <http://www.gnu.org/licenses/>.
# This file is part of the gdb testsuite
# This tests that C++ alignof works in gdb, and that it agrees with
# the compiler.
if {[skip_cplus_tests]} { continue }
# The types we're going to test.
set typelist {
char {unsigned char}
short {unsigned short}
int {unsigned int}
long {unsigned long}
{long long} {unsigned long long}
float
double {long double}
empty
bigenum
vstruct
bfstruct
arrstruct
derived
derived2
}
if {[has_int128_cxx]} {
# Note we don't check "unsigned __int128" yet because at least gcc
# canonicalizes the name to "__int128 unsigned", and there isn't a
# c-exp.y production for this.
# https://sourceware.org/bugzilla/show_bug.cgi?id=20991
lappend typelist __int128
}
# Create the test file.
set filename [standard_output_file align.cc]
set outfile [open $filename w]
# Prologue.
puts $outfile {
template<typename T, typename U>
struct align_pair
{
T one;
U two;
};
template<typename T, typename U>
struct align_union
{
T one;
U two;
};
enum bigenum { VALUE = 0xffffffffull };
struct empty { };
struct vstruct { virtual ~vstruct() {} char c; };
struct bfstruct { unsigned b : 3; };
struct arrstruct { short fld[7]; };
unsigned a_int3 = alignof (int[3]);
unsigned a_void = alignof (void);
struct base { char c; };
struct derived : public virtual base { int i; };
struct b2 : public virtual base { char d; };
struct derived2 : public b2, derived { char e; };
}
# First emit single items.
foreach type $typelist {
set utype [join [split $type] _]
puts $outfile "$type item_$utype;"
puts $outfile "unsigned a_$utype\n = alignof ($type);"
puts $outfile "typedef $type t_$utype;"
puts $outfile "t_$utype item_t_$utype;"
}
# Now emit all pairs.
foreach type $typelist {
set utype [join [split $type] _]
foreach inner $typelist {
set uinner [join [split $inner] _]
puts $outfile "align_pair<$type, $inner> item_${utype}_x_${uinner};"
puts $outfile "unsigned a_${utype}_x_${uinner}"
puts $outfile " = alignof (align_pair<$type, $inner>);"
puts $outfile "align_union<$type, $inner> item_${utype}_u_${uinner};"
puts $outfile "unsigned a_${utype}_u_${uinner}"
puts $outfile " = alignof (align_union<$type, $inner>);"
}
}
# Epilogue.
puts $outfile {
int main() {
return 0;
}
}
close $outfile
standard_testfile $filename
if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
{debug nowarnings c++ additional_flags=-std=c++11}]} {
return -1
}
if {![runto_main]} {
perror "test suppressed"
return
}
proc maybe_xfail {type} {
# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69560
# The g++ implementation of alignof is changing to match C11.
if {[is_x86_like_target]
&& [test_compiler_info {gcc-[0-8]-*}]
&& ($type == "double" || $type == "long long"
|| $type == "unsigned long long")} {
setup_xfail *-*-*
}
}
foreach type $typelist {
set utype [join [split $type] _]
set expected [get_integer_valueof a_$utype 0]
maybe_xfail $type
gdb_test "print alignof($type)" " = $expected"
maybe_xfail $type
gdb_test "print alignof(t_$utype)" " = $expected"
maybe_xfail $type
gdb_test "print alignof(typeof(item_$utype))" " = $expected"
foreach inner $typelist {
set uinner [join [split $inner] _]
set expected [get_integer_valueof a_${utype}_x_${uinner} 0]
gdb_test "print alignof(align_pair<${type},${inner}>)" " = $expected"
set expected [get_integer_valueof a_${utype}_u_${uinner} 0]
gdb_test "print alignof(align_union<${type},${inner}>)" " = $expected"
}
}
set expected [get_integer_valueof a_int3 0]
gdb_test "print alignof(int\[3\])" " = $expected"
set expected [get_integer_valueof a_void 0]
gdb_test "print alignof(void)" " = $expected"

83
gdb/testsuite/gdb.dwarf2/dw2-align.exp Normal file
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@ -0,0 +1,83 @@
# Copyright 2018 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 <http://www.gnu.org/licenses/>.
load_lib dwarf.exp
# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
return 0
}
standard_testfile main.c align-dw.S
# Make some DWARF for the test.
set asm_file [standard_output_file $srcfile2]
Dwarf::assemble $asm_file {
global srcdir subdir srcfile
cu {} {
DW_TAG_compile_unit {
{DW_AT_language @DW_LANG_C_plus_plus}
{DW_AT_name dw2-align.c}
{DW_AT_comp_dir /tmp}
} {
declare_labels itype ptype
itype: DW_TAG_base_type {
{DW_AT_byte_size 4 DW_FORM_sdata}
{DW_AT_encoding @DW_ATE_signed}
{DW_AT_name int_4096}
{DW_AT_alignment 4096 DW_FORM_sdata}
}
ptype: DW_TAG_pointer_type {
{DW_AT_byte_size 8 DW_FORM_sdata}
{DW_AT_type :$itype}
{DW_AT_alignment 4096 DW_FORM_sdata}
}
DW_TAG_typedef {
{DW_AT_name ptr_4096}
{DW_AT_type :$ptype}
}
DW_TAG_structure_type {
{DW_AT_name "struct_4096"}
{DW_AT_byte_size 4096 DW_FORM_sdata}
{DW_AT_alignment 4096 DW_FORM_udata}
} {
member {
{name a}
{type :$itype}
{data_member_location 0 data1}
}
}
}
}
}
if { [prepare_for_testing "failed to prepare" ${testfile} \
[list $srcfile $asm_file] {nodebug}] } {
return -1
}
if ![runto_main] {
return -1
}
gdb_test_no_output "set lang c++"
gdb_test "print alignof(int_4096)" " = 4096"
gdb_test "print alignof(ptr_4096)" " = 4096"
gdb_test "print alignof(struct_4096)" " = 4096"

30
gdb/testsuite/lib/gdb.exp
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@ -3003,6 +3003,36 @@ gdb_caching_proc skip_btrace_pt_tests {
return $skip_btrace_tests
}
# A helper that compiles a test case to see if __int128 is supported.
proc gdb_int128_helper {lang} {
set src [standard_temp_file i128[pid].c]
set obj [standard_temp_file i128[pid].o]
verbose -log "checking $lang for __int128"
gdb_produce_source $src {
__int128 x;
int main() { return 0; }
}
set lines [gdb_compile $src $obj object [list nowarnings quiet $lang]]
file delete $src
file delete $obj
set result [expr {!![string match "" $lines]}]
verbose -log "__int128 for $lang result = $result"
return $result
}
# Return true if the C compiler understands the __int128 type.
gdb_caching_proc has_int128_c {
return [gdb_int128_helper c]
}
# Return true if the C++ compiler understands the __int128 type.
gdb_caching_proc has_int128_cxx {
return [gdb_int128_helper c++]
}
# Return whether we should skip tests for showing inlined functions in
# backtraces. Requires get_compiler_info and get_debug_format.