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RISC-V: Fix C ABI for flattened struct with 0-length bitfield.

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gcc/
	PR target/91229
	* config/riscv/riscv.c (riscv_flatten_aggregate_field): New arg
	ignore_zero_width_bit_field_p.  Skip zero size bitfields when true.
	Pass into recursive call.
	(riscv_flatten_aggregate_argument): New arg.  Pass to
	riscv_flatten_aggregate_field.
	(riscv_pass_aggregate_in_fpr_pair_p): New local warned.  Call
	riscv_flatten_aggregate_argument twice, with false and true as last
	arg.  Process result twice.  Compare results and warn if different.
	(riscv_pass_aggregate_in_fpr_and_gpr_p): Likewise.

	gcc/testsuite/
	* gcc.target/riscv/flattened-struct-abi-1.c: New test.
	* gcc.target/riscv/flattened-struct-abi-2.c: New test.

From-SVN: r274215
This commit is contained in:
Jim Wilson 2019-08-08 19:04:56 +00:00 • committed by Jim Wilson
parent 355229f22a
commit e98c3ee971
5 changed files with 113 additions and 16 deletions
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13
gcc/ChangeLog
View file

@ -1,3 +1,16 @@
2019-08-08 Jim Wilson <jimw@sifive.com>
PR target/91229
* config/riscv/riscv.c (riscv_flatten_aggregate_field): New arg
ignore_zero_width_bit_field_p. Skip zero size bitfields when true.
Pass into recursive call.
(riscv_flatten_aggregate_argument): New arg. Pass to
riscv_flatten_aggregate_field.
(riscv_pass_aggregate_in_fpr_pair_p): New local warned. Call
riscv_flatten_aggregate_argument twice, with false and true as last
arg. Process result twice. Compare results and warn if different.
(riscv_pass_aggregate_in_fpr_and_gpr_p): Likewise.
2019-08-08 Martin Liska <mliska@suse.cz>
PR bootstrap/91352

92
gcc/config/riscv/riscv.c
View file

@ -2383,7 +2383,8 @@ typedef struct {
static int
riscv_flatten_aggregate_field (const_tree type,
riscv_aggregate_field fields[2],
int n, HOST_WIDE_INT offset)
int n, HOST_WIDE_INT offset,
bool ignore_zero_width_bit_field_p)
{
switch (TREE_CODE (type))
{
@ -2400,8 +2401,21 @@ riscv_flatten_aggregate_field (const_tree type,
if (!TYPE_P (TREE_TYPE (f)))
return -1;
HOST_WIDE_INT pos = offset + int_byte_position (f);
n = riscv_flatten_aggregate_field (TREE_TYPE (f), fields, n, pos);
/* The C++ front end strips zero-length bit-fields from structs.
So we need to ignore them in the C front end to make C code
compatible with C++ code. */
if (ignore_zero_width_bit_field_p
&& DECL_BIT_FIELD (f)
&& (DECL_SIZE (f) == NULL_TREE
|| integer_zerop (DECL_SIZE (f))))
;
else
{
HOST_WIDE_INT pos = offset + int_byte_position (f);
n = riscv_flatten_aggregate_field (TREE_TYPE (f),
fields, n, pos,
ignore_zero_width_bit_field_p);
}
if (n < 0)
return -1;
}
@ -2414,7 +2428,8 @@ riscv_flatten_aggregate_field (const_tree type,
tree index = TYPE_DOMAIN (type);
tree elt_size = TYPE_SIZE_UNIT (TREE_TYPE (type));
int n_subfields = riscv_flatten_aggregate_field (TREE_TYPE (type),
subfields, 0, offset);
subfields, 0, offset,
ignore_zero_width_bit_field_p);
/* Can't handle incomplete types nor sizes that are not fixed. */
if (n_subfields <= 0
@ -2487,12 +2502,14 @@ riscv_flatten_aggregate_field (const_tree type,
static int
riscv_flatten_aggregate_argument (const_tree type,
riscv_aggregate_field fields[2])
riscv_aggregate_field fields[2],
bool ignore_zero_width_bit_field_p)
{
if (!type || TREE_CODE (type) != RECORD_TYPE)
return -1;
return riscv_flatten_aggregate_field (type, fields, 0, 0);
return riscv_flatten_aggregate_field (type, fields, 0, 0,
ignore_zero_width_bit_field_p);
}
/* See whether TYPE is a record whose fields should be returned in one or
@ -2502,13 +2519,34 @@ static unsigned
riscv_pass_aggregate_in_fpr_pair_p (const_tree type,
riscv_aggregate_field fields[2])
{
int n = riscv_flatten_aggregate_argument (type, fields);
static int warned = 0;
for (int i = 0; i < n; i++)
/* This is the old ABI, which differs for C++ and C. */
int n_old = riscv_flatten_aggregate_argument (type, fields, false);
for (int i = 0; i < n_old; i++)
if (!SCALAR_FLOAT_TYPE_P (fields[i].type))
return 0;
{
n_old = -1;
break;
}
return n > 0 ? n : 0;
/* This is the new ABI, which is the same for C++ and C. */
int n_new = riscv_flatten_aggregate_argument (type, fields, true);
for (int i = 0; i < n_new; i++)
if (!SCALAR_FLOAT_TYPE_P (fields[i].type))
{
n_new = -1;
break;
}
if ((n_old != n_new) && (warned == 0))
{
warning (0, "ABI for flattened struct with zero-length bit-fields "
"changed in GCC 10");
warned = 1;
}
return n_new > 0 ? n_new : 0;
}
/* See whether TYPE is a record whose fields should be returned in one or
@ -2519,16 +2557,38 @@ static bool
riscv_pass_aggregate_in_fpr_and_gpr_p (const_tree type,
riscv_aggregate_field fields[2])
{
unsigned num_int = 0, num_float = 0;
int n = riscv_flatten_aggregate_argument (type, fields);
static int warned = 0;
for (int i = 0; i < n; i++)
/* This is the old ABI, which differs for C++ and C. */
unsigned num_int_old = 0, num_float_old = 0;
int n_old = riscv_flatten_aggregate_argument (type, fields, false);
for (int i = 0; i < n_old; i++)
{
num_float += SCALAR_FLOAT_TYPE_P (fields[i].type);
num_int += INTEGRAL_TYPE_P (fields[i].type);
num_float_old += SCALAR_FLOAT_TYPE_P (fields[i].type);
num_int_old += INTEGRAL_TYPE_P (fields[i].type);
}
return num_int == 1 && num_float == 1;
/* This is the new ABI, which is the same for C++ and C. */
unsigned num_int_new = 0, num_float_new = 0;
int n_new = riscv_flatten_aggregate_argument (type, fields, true);
for (int i = 0; i < n_new; i++)
{
num_float_new += SCALAR_FLOAT_TYPE_P (fields[i].type);
num_int_new += INTEGRAL_TYPE_P (fields[i].type);
}
if (((num_int_old == 1 && num_float_old == 1
&& (num_int_old != num_int_new || num_float_old != num_float_new))
|| (num_int_new == 1 && num_float_new == 1
&& (num_int_old != num_int_new || num_float_old != num_float_new)))
&& (warned == 0))
{
warning (0, "ABI for flattened struct with zero-length bit-fields "
"changed in GCC 10");
warned = 1;
}
return num_int_new == 1 && num_float_new == 1;
}
/* Return the representation of an argument passed or returned in an FPR

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2019-08-08 Jim Wilson <jimw@sifive.com>
PR target/91229
* gcc.target/riscv/flattened-struct-abi-1.c: New test.
* gcc.target/riscv/flattened-struct-abi-2.c: New test.
2019-08-08 Marek Polacek <polacek@redhat.com>
PR c++/79520

9
gcc/testsuite/gcc.target/riscv/flattened-struct-abi-1.c Normal file
View file

@ -0,0 +1,9 @@
/* { dg-do compile } */
/* { dg-options "-march=rv32gc -mabi=ilp32d" } */
struct s1 { int : 0; float f; int i; int : 0; };
void dummy(float, int);
void f(struct s1 s) { /* { dg-warning "flattened struct" } */
dummy(s.f + 1.0, s.i + 1);
}

9
gcc/testsuite/gcc.target/riscv/flattened-struct-abi-2.c Normal file
View file

@ -0,0 +1,9 @@
/* { dg-do compile } */
/* { dg-options "-march=rv32gc -mabi=ilp32d" } */
struct s1 { int : 0; float f; float g; int : 0; };
void dummy(float, float);
void f(struct s1 s) { /* { dg-warning "flattened struct" } */
dummy(s.f + 1.0, s.g + 2.0);
}