[PATCH 1/2] AArch64 AAPCS: Empty structs have non zero size in C++
Alan Hayward
Alan.Hayward@arm.com
Mon Jan 21 15:52:00 GMT 2019
Pushed with changes suggested, including all xpass matches.
Alan.
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index b051563937..7c5d74858d 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -1232,6 +1232,14 @@ aapcs_is_vfp_call_or_return_candidate_1 (struct type *type,
return -1;
count += sub_count;
}
+
+ /* Ensure there is no padding between the fields (allowing for empty
+ zero length structs) */
+ int ftype_length = (*fundamental_type == nullptr)
+ ? 0 : TYPE_LENGTH (*fundamental_type);
+ if (count * ftype_length != TYPE_LENGTH (type))
+ return -1;
+
return count;
}
diff --git a/gdb/testsuite/gdb.base/infcall-nested-structs.exp b/gdb/testsuite/gdb.base/infcall-nested-structs.exp
index b04d9aaa84..d7d1e3e00d 100644
--- a/gdb/testsuite/gdb.base/infcall-nested-structs.exp
+++ b/gdb/testsuite/gdb.base/infcall-nested-structs.exp
@@ -24,6 +24,20 @@ if [target_info exists gdb,cannot_call_functions] {
continue
}
+# 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++}
+}
+
+foreach l $lang {
+ set dir "$l"
+ remote_exec host "rm -rf [standard_output_file ${dir}]"
+ remote_exec host "mkdir -p [standard_output_file ${dir}]"
+}
+
+
set int_types { tc ts ti tl tll }
set float_types { tf td tld }
set complex_types { tfc tdc tldc }
@@ -31,6 +45,7 @@ set complex_types { tfc tdc tldc }
set compile_flags {debug}
if [support_complex_tests] {
lappend compile_flags "additional_flags=-DTEST_COMPLEX"
+ lappend compile_flags "additional_flags=-Wno-psabi"
}
# Given N (0..25), return the corresponding alphabetic letter in upper
@@ -44,7 +59,7 @@ proc I2A { n } {
# types of the struct fields within the source. Run up to main.
# Also updates the global "testfile" to reflect the most recent build.
-proc start_nested_structs_test { types } {
+proc start_nested_structs_test { lang types } {
global testfile
global srcfile
global binfile
@@ -53,9 +68,11 @@ proc start_nested_structs_test { types } {
global compile_flags
standard_testfile .c
+ set dir "$lang"
# Create the additional flags
set flags $compile_flags
+ lappend flags $lang
for {set n 0} {$n<[llength ${types}]} {incr n} {
set m [I2A ${n}]
@@ -64,7 +81,7 @@ proc start_nested_structs_test { types } {
append testfile "-" "$t"
}
- set binfile [standard_output_file ${testfile}]
+ set binfile [standard_output_file ${dir}/${testfile}]
if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable "${flags}"] != "" } {
unresolved "failed to compile"
return 0
@@ -99,13 +116,21 @@ proc start_nested_structs_test { types } {
# Assuming GDB is stopped at main within a test binary, run some tests
# passing structures, and reading return value structures.
-proc run_tests {} {
+proc run_tests { lang types } {
global gdb_prompt
foreach {name} {struct_01_01 struct_01_02 struct_01_03 struct_01_04
struct_02_01 struct_02_02 struct_02_03 struct_02_04
struct_04_01 struct_04_02 struct_04_03 struct_04_04
struct_05_01 struct_05_02 struct_05_03 struct_05_04} {
+
+ if { ( $lang == "c++"
+ && ( ( [regexp "struct_01_0(1|2|3)" $name match] && [regexp "^types-(td($|-)|tl(|l)(|-tf|-td|-tld)$)" $types match] )
+ || ( $name == "struct_01_02" && $types == "types-tfc" )
+ || ( $name == "struct_01_04" && [regexp "^types-(tf($|-)|ti(|-tf|-td|-tld)$)" $types match] )
+ || ( $name == "struct_02_01" && [regexp "^types-tf-t(c|s|i)" $types match] ) ) ) } {
+ setup_xfail gdb/24104 "x86_64-*-linux*"
+ }
gdb_test "p/d check_arg_${name} (ref_val_${name})" "= 1"
set refval [ get_valueof "" "ref_val_${name}" "" ]
@@ -113,8 +138,13 @@ proc run_tests {} {
set test "check return value ${name}"
if { ${refval} != "" } {
+
set answer [ get_valueof "" "rtn_str_${name} ()" "XXXX"]
verbose -log "Answer: ${answer}"
+
+ if { ($lang == "c++" && $name == "struct_02_01" && [regexp "^types-(tf-t(c|s|i)|t(c|s|i)-tf)" $types match] ) } {
+ setup_xfail gdb/24104 "x86_64-*-linux*"
+ }
gdb_assert [string eq ${answer} ${refval}] ${test}
} else {
unresolved $test
@@ -125,48 +155,50 @@ proc run_tests {} {
# Set up a test prefix, compile the test binary, run to main, and then
# run some tests.
-proc start_gdb_and_run_tests { types } {
+proc start_gdb_and_run_tests { lang types } {
set prefix "types"
foreach t $types {
append prefix "-" "${t}"
}
- with_test_prefix $prefix {
- if { [start_nested_structs_test $types] } {
- run_tests
+ foreach_with_prefix l $lang {
+ with_test_prefix $prefix {
+ if { [start_nested_structs_test $l $types] } {
+ run_tests $l $prefix
+ }
}
}
}
foreach ta $int_types {
- start_gdb_and_run_tests $ta
+ start_gdb_and_run_tests $lang $ta
}
if [support_complex_tests] {
foreach ta $complex_types {
- start_gdb_and_run_tests $ta
+ start_gdb_and_run_tests $lang $ta
}
}
if ![gdb_skip_float_test] {
foreach ta $float_types {
- start_gdb_and_run_tests $ta
+ start_gdb_and_run_tests $lang $ta
}
foreach ta $int_types {
foreach tb $float_types {
- start_gdb_and_run_tests [list $ta $tb]
+ start_gdb_and_run_tests $lang [list $ta $tb]
}
}
foreach ta $float_types {
foreach tb $int_types {
- start_gdb_and_run_tests [list $ta $tb]
+ start_gdb_and_run_tests $lang [list $ta $tb]
}
foreach tb $float_types {
- start_gdb_and_run_tests [list $ta $tb]
+ start_gdb_and_run_tests $lang [list $ta $tb]
}
}
}
> On 18 Jan 2019, at 10:34, Alan Hayward <Alan.Hayward@arm.com> wrote:
>
> (Thanks, would have pushed, but outstanding question below)…
>
>
>> On 17 Jan 2019, at 17:08, Pedro Alves <palves@redhat.com> wrote:
>>
>> On 01/16/2019 03:57 PM, Alan Hayward wrote:
>>> When gdb.base/infcall-nested-structs.c is complied as C++, the structs
>>> containing empty structs are no longer passed via float arguments.
>>
>> This reads a bit ambiguously. Which is it?
>>
>> #1 - No longer passed by GCC, but GDB still passes.
>> #2 - No longer passed by GDB, but GCC still passes.
>>
>>> This is because structs in C++ have a minimum size of 1. This can then
>>> cause padding in the struct, which is disallowed for AAPCS.
>>
>> Does this "disallowed" mean that structs with padding are
>> not allowed to be passed via float arguments? Took me a while to
>> grok that.
>>
>> It'd be good to clarify the commit log.
>
> I’ll change to:
> When gdb.base/infcall-nested-structs.c is complied as C++, the compiler
> will not pass structs containing empty structs via float arguments.
> This is because structs in C++ have a minimum size of 1, causing padding
> in the struct. The AAPCS does not allow structs with padding to be
> passed in float arguments.
>
>>> +foreach l $lang {
>>> + set dir "$l"
>>> + remote_exec build "rm -rf [standard_output_file ${dir}]"
>>> + remote_exec build "mkdir -p [standard_output_file ${dir}]"
>>
>> I think these should be
>>
>> remote_exec host
>>
>> not "build" ?
>>
>> For remote-host testing, where the compiler and debugger run on the
>> host machine.
>>
>
> This was due to copying from another test - I’ll raise a quick
> patch to fix those up too.
>
>
>> Could you please file a bug for the x86 internal errors, and
>> kfail the test for x86?
>>
>
> Will raise a bug.
>
> The pattern for which tests pass and fail is not that simple.
> Each structure gets tested 49 times on c++ (with different types).
> Eg: For struct_01_01, 17 of them fail, but for struct_01_04 only
> 13 fail.
>
> Is it ok to be over cautious (and have some XPASS results)
> or do we really need a large messy if statement with all the
> exact matches?
>
>
>> Otherwise looks fine to me.
>>
>> Thanks,
>> Pedro Alves
>>
>>> +}
>>> +
>>> +
>>> set int_types { tc ts ti tl tll }
>>> set float_types { tf td tld }
>>> set complex_types { tfc tdc tldc }
>>> @@ -44,7 +58,7 @@ proc I2A { n } {
>>> # types of the struct fields within the source. Run up to main.
>>> # Also updates the global "testfile" to reflect the most recent build.
>>>
>>> -proc start_nested_structs_test { types } {
>>> +proc start_nested_structs_test { lang types } {
>>> global testfile
>>> global srcfile
>>> global binfile
>>> @@ -53,9 +67,11 @@ proc start_nested_structs_test { types } {
>>> global compile_flags
>>>
>>> standard_testfile .c
>>> + set dir "$lang"
>>>
>>> # Create the additional flags
>>> set flags $compile_flags
>>> + lappend flags $lang
>>>
>>> for {set n 0} {$n<[llength ${types}]} {incr n} {
>>> set m [I2A ${n}]
>>> @@ -64,7 +80,7 @@ proc start_nested_structs_test { types } {
>>> append testfile "-" "$t"
>>> }
>>>
>>> - set binfile [standard_output_file ${testfile}]
>>> + set binfile [standard_output_file ${dir}/${testfile}]
>>> if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable "${flags}"] != "" } {
>>> unresolved "failed to compile"
>>> return 0
>>> @@ -125,48 +141,50 @@ proc run_tests {} {
>>> # Set up a test prefix, compile the test binary, run to main, and then
>>> # run some tests.
>>>
>>> -proc start_gdb_and_run_tests { types } {
>>> +proc start_gdb_and_run_tests { lang types } {
>>
>>> set prefix "types"
>>>
>>> foreach t $types {
>>> append prefix "-" "${t}"
>>> }
>>>
>>> - with_test_prefix $prefix {
>>> - if { [start_nested_structs_test $types] } {
>>> - run_tests
>>> + foreach_with_prefix l $lang {
>>> + with_test_prefix $prefix {
>>> + if { [start_nested_structs_test $l $types] } {
>>> + run_tests
>>> + }
>>> }
>>> }
>>> }
>>>
>>> foreach ta $int_types {
>>> - start_gdb_and_run_tests $ta
>>> + start_gdb_and_run_tests $lang $ta
>>> }
>>>
>>> if [support_complex_tests] {
>>> foreach ta $complex_types {
>>> - start_gdb_and_run_tests $ta
>>> + start_gdb_and_run_tests $lang $ta
>>> }
>>> }
>>>
>>> if ![gdb_skip_float_test] {
>>> foreach ta $float_types {
>>> - start_gdb_and_run_tests $ta
>>> + start_gdb_and_run_tests $lang $ta
>>> }
>>>
>>> foreach ta $int_types {
>>> foreach tb $float_types {
>>> - start_gdb_and_run_tests [list $ta $tb]
>>> + start_gdb_and_run_tests $lang [list $ta $tb]
>>> }
>>> }
>>>
>>> foreach ta $float_types {
>>> foreach tb $int_types {
>>> - start_gdb_and_run_tests [list $ta $tb]
>>> + start_gdb_and_run_tests $lang [list $ta $tb]
>>> }
>>>
>>> foreach tb $float_types {
>>> - start_gdb_and_run_tests [list $ta $tb]
>>> + start_gdb_and_run_tests $lang [list $ta $tb]
>>> }
>>> }
>>> }
>>>
>>
>
More information about the Gdb-patches
mailing list