[PATCH 1/7] Fix function argument and return value locations

Hannes Domani
2020-05-25T18:57:33Z

Fixes these testsuite fails on Windows:
FAIL: gdb.base/callfuncs.exp: p t_float_complex_values(fc1, fc2)
FAIL: gdb.base/callfuncs.exp: p t_float_complex_many_args(fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4)
FAIL: gdb.base/callfuncs.exp: noproto: p t_float_complex_values(fc1, fc2)
FAIL: gdb.base/callfuncs.exp: noproto: p t_float_complex_many_args(fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4)
FAIL: gdb.base/call-sc.exp: p/c fun(); call call-sc-tld
FAIL: gdb.base/call-sc.exp: advance to fun for return; return call-sc-tld
FAIL: gdb.base/call-sc.exp: zed L for return; return call-sc-tld
FAIL: gdb.base/call-sc.exp: return foo; return call-sc-tld
FAIL: gdb.base/call-sc.exp: return foo; synchronize pc to main() for 'call-sc-tld'
FAIL: gdb.base/call-sc.exp: return foo; synchronize pc to main() for 'call-sc-tld'
FAIL: gdb.base/call-sc.exp: advance to fun for finish; return call-sc-tld
FAIL: gdb.base/call-sc.exp: zed L for finish; return call-sc-tld
FAIL: gdb.base/call-sc.exp: finish foo; return call-sc-tld (the program is no longer running)
FAIL: gdb.base/call-sc.exp: value foo finished; return call-sc-tld

For function arguments (callfuncs.exp), only TYPE_CODE_COMPLEX was
missing in the types passed via XMM registers.

For return values, there were a lot more issues:
- TYPE_CODE_DECFLOAT is NOT returned via XMM0.
- long double is NOT returned via XMM0.
- but __int128 IS returned via XMM0.
- the comments for TYPE_CODE_FLT state that __m128, __m128i and __m128d are
returned by XMM0, and this is correct, but it doesn't actually check for
them, because they are TYPE_CODE_ARRAY with TYPE_VECTOR

So I had to add TYPE_CODE_DECFLOAT to the arguments passed via XMM register,
but I had to remove it from the values returned via XMM0 register.

gdb/ChangeLog:

2020-05-25 Hannes Domani <ssbssa@yahoo.de>

* amd64-windows-tdep.c (amd64_windows_passed_by_xmm_register):
Add TYPE_CODE_COMPLEX.
(amd64_windows_return_value): Fix types returned via XMM0.

gdb/testsuite/ChangeLog:

2020-05-25 Hannes Domani <ssbssa@yahoo.de>

* gdb.base/call-sc.c: Fix return struct on stack test case.
* gdb.base/call-sc.exp: Likewise.
---
gdb/amd64-windows-tdep.c | 23 ++++++++++++++++++-----
gdb/testsuite/gdb.base/call-sc.c | 6 +++++-
gdb/testsuite/gdb.base/call-sc.exp | 13 +++++++++++++
3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/gdb/amd64-windows-tdep.c b/gdb/amd64-windows-tdep.c
index 487dfd45fc..db9845203f 100644
--- a/gdb/amd64-windows-tdep.c
+++ b/gdb/amd64-windows-tdep.c
@@ -77,7 +77,8 @@ static int
amd64_windows_passed_by_xmm_register (struct type *type)
{
return ((type->code () == TYPE_CODE_FLT
- || type->code () == TYPE_CODE_DECFLOAT)
+ || type->code () == TYPE_CODE_DECFLOAT
+ || type->code () == TYPE_CODE_COMPLEX)
&& (TYPE_LENGTH (type) == 4 || TYPE_LENGTH (type) == 8));
}

@@ -299,17 +300,29 @@ amd64_windows_return_value (struct gdbarch *gdbarch, struct value *function,
switch (type->code ())
{
case TYPE_CODE_FLT:
- case TYPE_CODE_DECFLOAT:
- /* __m128, __m128i, __m128d, floats, and doubles are returned
- via XMM0. */
- if (len == 4 || len == 8 || len == 16)
+ /* floats, and doubles are returned via XMM0. */
+ if (len == 4 || len == 8)
regnum = AMD64_XMM0_REGNUM;
break;
+ case TYPE_CODE_ARRAY:
+ /* __m128, __m128i and __m128d are returned via XMM0. */
+ if (TYPE_VECTOR (type) && len == 16)
+ {
+ enum type_code code = TYPE_TARGET_TYPE (type)->code ();
+ if (code == TYPE_CODE_INT || code == TYPE_CODE_FLT)
+ {
+ regnum = AMD64_XMM0_REGNUM;
+ break;
+ }
+ }
+ /* fall through */
default:
/* All other values that are 1, 2, 4 or 8 bytes long are returned
via RAX. */
if (len == 1 || len == 2 || len == 4 || len == 8)
regnum = AMD64_RAX_REGNUM;
+ else if (len == 16 && type->code () == TYPE_CODE_INT)
+ regnum = AMD64_XMM0_REGNUM;
break;
}

diff --git a/gdb/testsuite/gdb.base/call-sc.c b/gdb/testsuite/gdb.base/call-sc.c
index ba80576ac3..eb140cd9cf 100644
--- a/gdb/testsuite/gdb.base/call-sc.c
+++ b/gdb/testsuite/gdb.base/call-sc.c
@@ -35,6 +35,7 @@ typedef t T;
#endif

T foo = '1', L;
+T init = '9';

T fun()
{
@@ -55,7 +56,10 @@ int main()
{
int i;

- Fun(foo);
+ /* Use a different initial value then is later used in the
+ "value foo returned" test, so in case the struct is then returned
+ on the stack, it doesn't have the correct value by accident. */
+ Fun(init);

/* An infinite loop that first clears all the variables and then
calls the function. This "hack" is to make re-testing easier -
diff --git a/gdb/testsuite/gdb.base/call-sc.exp b/gdb/testsuite/gdb.base/call-sc.exp
index 719000435a..9697c5ac24 100644
--- a/gdb/testsuite/gdb.base/call-sc.exp
+++ b/gdb/testsuite/gdb.base/call-sc.exp
@@ -291,6 +291,19 @@ proc test_scalar_returns { } {
fail "${test}"
}
}
+ -re " = 57 .*${gdb_prompt} $" {
+ if $return_value_unknown {
+ # The struct return case.
+ # The return value is stored on the stack, and since GDB
+ # didn't override it, it still has value that was stored
+ # there in the earlier Foo(init) call.
+ pass "${test}"
+ } else {
+ # This contradicts the above claim that GDB knew
+ # the location of the return-value.
+ fail "${test}"
+ }
+ }
-re ".*${gdb_prompt} $" {
if $return_value_unimplemented {
# What a suprize. The architecture hasn't implemented
--
2.26.2