gdb: Handle alignment for C++ structures with static members

In 'type_align' when computing the alignment of a structure we should
not consider the alignment of static structure members, these are
usually stored outside of the structure and therefore don't have any
impact on the structures alignment requirements.

I've extended the existing alignment calculating test to compile in
both C and C++ now so that we can create structures with static
members.

gdb/ChangeLog:

	* gdbtypes.c (type_align): Don't consider static members when
	computing structure alignment.

gdb/testsuite/ChangeLog:

	* gdb.base/align.exp: Extend to compile in both C and C++, and add
	tests for structs with static members.
This commit is contained in:
Andrew Burgess 2019-02-22 22:04:53 +00:00
parent 5561fc304f
commit bf9a735e23
4 changed files with 154 additions and 67 deletions

View File

@ -1,3 +1,8 @@
2019-02-27 Andrew Burgess <andrew.burgess@embecosm.com>
* gdbtypes.c (type_align): Don't consider static members when
computing structure alignment.
2019-02-27 Andrew Burgess <andrew.burgess@embecosm.com>
* arc-tdep.c (arc_type_align): Provide alignment for basic types,

View File

@ -3039,15 +3039,18 @@ type_align (struct type *type)
}
for (unsigned i = 0; i < TYPE_NFIELDS (type); ++i)
{
ULONGEST f_align = type_align (TYPE_FIELD_TYPE (type, i));
if (f_align == 0)
if (!field_is_static (&TYPE_FIELD (type, i)))
{
/* Don't pretend we know something we don't. */
align = 0;
break;
ULONGEST f_align = type_align (TYPE_FIELD_TYPE (type, i));
if (f_align == 0)
{
/* Don't pretend we know something we don't. */
align = 0;
break;
}
if (f_align > align)
align = f_align;
}
if (f_align > align)
align = f_align;
}
}
break;

View File

@ -1,3 +1,8 @@
2019-02-27 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.base/align.exp: Extend to compile in both C and C++, and add
tests for structs with static members.
2019-02-26 Tom Tromey <tromey@adacore.com>
* gdb.python/py-value.exp (test_value_from_buffer): Check for

View File

@ -15,8 +15,15 @@
# This file is part of the gdb testsuite
# This tests that C11 _Alignof works in gdb, and that it agrees with
# the compiler.
# This tests that C11 _Alignof and C++11 alignof works in gdb, and
# that it agrees with the compiler.
# Only test C++ if we are able. Always use C.
if { [skip_cplus_tests] || [get_compiler_info "c++"] } {
set lang {c}
} else {
set lang {c c++}
}
# The types we're going to test.
@ -38,72 +45,139 @@ if {[has_int128_c]} {
lappend typelist __int128
}
# Create the test file.
# Build source file for testing alignment handling of language LANG.
# Returns the name of the newly created source file.
proc prepare_test_source_file { lang } {
global typelist
set filename [standard_output_file align.c]
set outfile [open $filename w]
# Create the test file.
# 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;"
if { $lang == "c++" } {
set suffix "cpp"
set align_func "alignof"
} else {
set suffix "c"
set align_func "_Alignof"
}
puts $outfile "$type item_$utype;"
puts $outfile "unsigned a_$utype\n = _Alignof ($type);"
set utype [join [split $type] _]
set filename [standard_output_file "$lang/align.$suffix"]
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; }"
if { $lang == "c++" } {
puts -nonewline $outfile "#define DEF_WITH_STATIC(T,U) struct align_pair_static_ ## T ## _x_ ## U "
puts $outfile "{ static T one; U two; }"
}
if { $lang == "c" } {
puts $outfile "unsigned a_void = ${align_func} (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;"
if { $lang == "c" } {
puts $outfile "unsigned a_$utype\n = ${align_func} ($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 " = ${align_func} (struct align_pair_${joined});"
if { $lang == "c++" } {
puts $outfile "DEF_WITH_STATIC ($utype, $uinner);"
set joined "${utype}_x_${uinner}"
puts $outfile "struct align_pair_static_$joined item_static_${joined};"
puts $outfile "unsigned a_static_${joined}"
puts $outfile " = ${align_func} (struct align_pair_static_${joined});"
}
}
}
# Epilogue.
puts $outfile {
int main() {
return 0;
}
}
close $outfile
return $filename
}
# 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});"
# Run the alignment test for the language LANG.
proc run_alignment_test { lang } {
global testfile srcfile typelist
global subdir
set filename [prepare_test_source_file $lang]
standard_testfile $filename
if {[prepare_for_testing "failed to prepare" "$lang/$testfile" $srcfile {debug}]} {
return -1
}
if {![runto_main]} {
perror "test suppressed"
return
}
if { $lang == "c++" } {
set align_func "alignof"
} else {
set align_func "_Alignof"
}
foreach type $typelist {
set utype [join [split $type] _]
if { $lang == "c" } {
set expected [get_integer_valueof a_$utype 0]
gdb_test "print ${align_func}($type)" " = $expected"
}
foreach inner $typelist {
set uinner [join [split $inner] _]
set expected [get_integer_valueof a_${utype}_x_${uinner} 0]
gdb_test "print ${align_func}(struct align_pair_${utype}_x_${uinner})" \
" = $expected"
if { $lang == "c++" } {
set expected [get_integer_valueof a_static_${utype}_x_${uinner} 0]
gdb_test "print ${align_func}(struct align_pair_static_${utype}_x_${uinner})" \
" = $expected"
}
}
}
if { $lang == "c" } {
set expected [get_integer_valueof a_void 0]
gdb_test "print ${align_func}(void)" " = $expected"
}
}
# Epilogue.
puts $outfile {
int main() {
return 0;
}
# Create nested 'c' and 'c++' directories within this tests directory.
foreach l $lang {
set dir "$l"
remote_exec host "rm -rf [standard_output_file ${dir}]"
remote_exec host "mkdir -p [standard_output_file ${dir}]"
}
close $outfile
standard_testfile $filename
if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug}]} {
return -1
# Now run the test for each language.
foreach_with_prefix l $lang {
run_alignment_test $l
}
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"