[DTrace-devel] [PATCH v3 21/61] Promote integers to 64 bits when loaded
Kris Van Hees
kris.van.hees at oracle.com
Thu Aug 4 12:26:31 UTC 2022
On Wed, Aug 03, 2022 at 07:12:10PM -0400, eugene.loh--- via DTrace-devel wrote:
> From: Eugene Loh <eugene.loh at oracle.com>
>
> DTrace internally implements integers with 64-bit registers. This
> makes the manipulation of integers of different sizes simpler, by
> avoiding a number of typecast operations. But DTrace has also
> loaded integers without promoting them appropriately. E.g.,
> ((short)0xffff) has been treated as 0xffff rather than -1.
>
> Promote integers to 64 bits when loading.
Promote signed integers...
since BPF already ensures that higher order bits are 0 when you load an
integer that is less than 64 bits wide.
> Add tests. Specifically, typecasting should typically not be needed.
> Therefore, operations such as x=y and x+y (of different types) should
> work properly if integers are correctly represented in 64-bit registers.
Since you specifically mention typecasting should typically not be needed,
naming the function dt_cg_typecast_64() seems a bit odd. I owuld suggest
we name this dt_cg_promote() since that is what it is doing. I think we
can leave off a _64 suffix since it is a promotion to native size.
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
> ---
> libdtrace/dt_cg.c | 16 ++++
> test/unittest/arithmetic/tst.cast-add.d | 116 ++++++++++++++++++++++++
> test/unittest/arithmetic/tst.cast-add.r | 37 ++++++++
> test/unittest/arithmetic/tst.cast-imp.d | 112 +++++++++++++++++++++++
> test/unittest/arithmetic/tst.cast-imp.r | 43 +++++++++
> 5 files changed, 324 insertions(+)
> create mode 100644 test/unittest/arithmetic/tst.cast-add.d
> create mode 100644 test/unittest/arithmetic/tst.cast-add.r
> create mode 100644 test/unittest/arithmetic/tst.cast-imp.d
> create mode 100644 test/unittest/arithmetic/tst.cast-imp.r
>
> diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
> index 4dc939fb..f77e239b 100644
> --- a/libdtrace/dt_cg.c
> +++ b/libdtrace/dt_cg.c
> @@ -2144,6 +2144,20 @@ dt_cg_ldsize(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type, ssize_t *ret_size)
> return ldstw[size];
> }
>
> +/*
> + * Generate code for typecast and promotion to 64 bits.
> + */
> +static void
> +dt_cg_typecast_64(const dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> +{
> + int n = sizeof(uint64_t) * NBBY - dt_node_type_size(dnp) * NBBY;
> +
> + if (n == 0)
> + return;
> + emit(dlp, BPF_ALU64_IMM(BPF_LSH, dnp->dn_reg, n));
> + emit(dlp, BPF_ALU64_IMM((dnp->dn_flags & DT_NF_SIGNED) ? BPF_ARSH : BPF_RSH, dnp->dn_reg, n));
> +}
How about:
/*
* Generate code to promote signed scalars (size < 64 bits) to native register
* size (64 bits).
*/
static void
dt_cg_promote(const dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
{
int n;
if (!(dnp->dn_flags & DT_NF_SIGNED))
return;
n = (sizeof(uint64_t) - dt_node_type_size(dnp)) * NBBY;
if (n == 0)
return;
emit(dlp, BPF_ALU64_IMM(BPF_LSH, dnp->dn_reg, n));
emit(dlp, BPF_ALU64_IMM(BPF_ARSH, dnp->dn_reg, n));
}
> +
> static void
> dt_cg_load_var(dt_node_t *dst, dt_irlist_t *dlp, dt_regset_t *drp)
> {
> @@ -2176,6 +2190,7 @@ dt_cg_load_var(dt_node_t *dst, dt_irlist_t *dlp, dt_regset_t *drp)
> (size & (size - 1)) == 0);
>
> emit(dlp, BPF_LOAD(ldstw[size], dst->dn_reg, dst->dn_reg, idp->di_offset));
> + dt_cg_typecast_64(dst, dlp, drp);
> }
>
> return;
> @@ -2216,6 +2231,7 @@ dt_cg_load_var(dt_node_t *dst, dt_irlist_t *dlp, dt_regset_t *drp)
> emit(dlp, BPF_JUMP(lbl_done));
> emitl(dlp, lbl_notnull,
> BPF_LOAD(ldstw[size], dst->dn_reg, BPF_REG_0, 0));
> + dt_cg_typecast_64(dst, dlp, drp);
> dt_regset_free(drp, BPF_REG_0);
>
> emitl(dlp, lbl_done,
> diff --git a/test/unittest/arithmetic/tst.cast-add.d b/test/unittest/arithmetic/tst.cast-add.d
> new file mode 100644
> index 00000000..c3a4d90d
> --- /dev/null
> +++ b/test/unittest/arithmetic/tst.cast-add.d
> @@ -0,0 +1,116 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Integers are promoted correctly for mixed-type adds.
> + * The .r results file can be generated by copying this file
> + * to a .c file and compiling the resulting C program.
> + *
> + * SECTION: Types, Operators, and Expressions/Arithmetic Operators
> + */
> +/* @@runtest-opts: -qC -DUSE_AS_D_SCRIPT */
> +
> +#ifndef USE_AS_D_SCRIPT
> +#include <stdio.h>
> +#endif
> +
> +signed char c;
> +short s;
> +int i;
> +long long l;
> +unsigned char C;
> +unsigned short S;
> +unsigned int I;
> +unsigned long long L;
> +
> +#ifdef USE_AS_D_SCRIPT
> +#define FMT " %d"
> +#define USE_FMT(f)
> +#else
> +char *fmt;
> +#define FMT fmt
> +#define USE_FMT(f) fmt = f;
> +#endif
> +
> +#define TEST(x, y) \
> + x = -2; y = -3; printf(FMT, x + y); printf(FMT, y + x); \
> + x = -2; y = +3; printf(FMT, x + y); printf(FMT, y + x); \
> + x = +2; y = -3; printf(FMT, x + y); printf(FMT, y + x); \
> + x = +2; y = +3; printf(FMT, x + y); printf(FMT, y + x); printf("\n");
> +
> +#ifdef USE_AS_D_SCRIPT
> +BEGIN
> +#else
> +int main(int c_unused, char *v_unused)
> +#endif
> +{
> + /* cast to signed char */
> + USE_FMT(" %hhd");
> + TEST(c, c)
> +
> + /* cast to unsigned char */
> + USE_FMT(" %hhu");
> + TEST(C, c)
> + TEST(C, C)
> +
> + /* cast to short */
> + USE_FMT(" %hd");
> + TEST(s, c)
> + TEST(s, C)
> + TEST(s, s)
> +
> + /* cast to unsigned short */
> + USE_FMT(" %hu");
> + TEST(S, c)
> + TEST(S, C)
> + TEST(S, s)
> + TEST(S, S)
> +
> + /* cast to int */
> + USE_FMT(" %d");
> + TEST(i, c)
> + TEST(i, C)
> + TEST(i, s)
> + TEST(i, S)
> + TEST(i, i)
> +
> + /* cast to unsigned int */
> + USE_FMT(" %u");
> + TEST(I, c)
> + TEST(I, C)
> + TEST(I, s)
> + TEST(I, S)
> + TEST(I, i)
> + TEST(I, I)
> +
> + /* cast to long long */
> + USE_FMT(" %lld");
> + TEST(l, c)
> + TEST(l, C)
> + TEST(l, s)
> + TEST(l, S)
> + TEST(l, i)
> + TEST(l, I)
> + TEST(l, l)
> +
> + /* cast to unsigned long long */
> + USE_FMT(" %llu");
> + TEST(L, c)
> + TEST(L, C)
> + TEST(L, s)
> + TEST(L, S)
> + TEST(L, i)
> + TEST(L, I)
> + TEST(L, l)
> + TEST(L, L)
> +
> +#ifdef USE_AS_D_SCRIPT
> + exit (0);
> +#else
> + return 0;
> +#endif
> +}
> diff --git a/test/unittest/arithmetic/tst.cast-add.r b/test/unittest/arithmetic/tst.cast-add.r
> new file mode 100644
> index 00000000..778b88e0
> --- /dev/null
> +++ b/test/unittest/arithmetic/tst.cast-add.r
> @@ -0,0 +1,37 @@
> + -6 -6 6 6 -6 -6 6 6
> + 251 251 1 1 255 255 5 5
> + 250 250 6 6 250 250 6 6
> + -5 -5 1 1 -1 -1 5 5
> + 251 251 1 1 255 255 5 5
> + -6 -6 6 6 -6 -6 6 6
> + 65531 65531 1 1 65535 65535 5 5
> + 251 251 1 1 255 255 5 5
> + 65531 65531 1 1 65535 65535 5 5
> + 65530 65530 6 6 65530 65530 6 6
> + -5 -5 1 1 -1 -1 5 5
> + 251 251 1 1 255 255 5 5
> + -5 -5 1 1 -1 -1 5 5
> + 65531 65531 1 1 65535 65535 5 5
> + -6 -6 6 6 -6 -6 6 6
> + 4294967291 4294967291 1 1 4294967295 4294967295 5 5
> + 251 251 1 1 255 255 5 5
> + 4294967291 4294967291 1 1 4294967295 4294967295 5 5
> + 65531 65531 1 1 65535 65535 5 5
> + 4294967291 4294967291 1 1 4294967295 4294967295 5 5
> + 4294967290 4294967290 6 6 4294967290 4294967290 6 6
> + -5 -5 1 1 -1 -1 5 5
> + 251 251 1 1 255 255 5 5
> + -5 -5 1 1 -1 -1 5 5
> + 65531 65531 1 1 65535 65535 5 5
> + -5 -5 1 1 -1 -1 5 5
> + 4294967291 4294967291 1 1 4294967295 4294967295 5 5
> + -6 -6 6 6 -6 -6 6 6
> + 18446744073709551611 18446744073709551611 1 1 18446744073709551615 18446744073709551615 5 5
> + 251 251 1 1 255 255 5 5
> + 18446744073709551611 18446744073709551611 1 1 18446744073709551615 18446744073709551615 5 5
> + 65531 65531 1 1 65535 65535 5 5
> + 18446744073709551611 18446744073709551611 1 1 18446744073709551615 18446744073709551615 5 5
> + 4294967291 4294967291 1 1 4294967295 4294967295 5 5
> + 18446744073709551611 18446744073709551611 1 1 18446744073709551615 18446744073709551615 5 5
> + 18446744073709551610 18446744073709551610 6 6 18446744073709551610 18446744073709551610 6 6
> +
> diff --git a/test/unittest/arithmetic/tst.cast-imp.d b/test/unittest/arithmetic/tst.cast-imp.d
> new file mode 100644
> index 00000000..dbce9893
> --- /dev/null
> +++ b/test/unittest/arithmetic/tst.cast-imp.d
> @@ -0,0 +1,112 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Integers are typecast correctly. (implicit)
> + * The .r results file can be generated by copying this file
> + * to a .c file and compiling the resulting C program.
> + *
> + * SECTION: Types, Operators, and Expressions/Arithmetic Operators
> + */
> +/* @@runtest-opts: -qC -DUSE_AS_D_SCRIPT */
> +
> +#ifndef USE_AS_D_SCRIPT
> +#include <stdio.h>
> +#endif
> +
> +signed char c, c0;
> +short s, s0;
> +int i, i0;
> +long long l, l0;
> +unsigned char C, C0;
> +unsigned short S, S0;
> +unsigned int I, I0;
> +unsigned long long L, L0;
> +
> +#ifdef USE_AS_D_SCRIPT
> +#define FMT "%d %d %d %d %d %d %d %d\n"
> +#else
> +#define FMT "%hhd %hd %d %lld %hhu %hu %u %llu\n"
> +#endif
> +
> +#define TEST(x) \
> + c = (x); s = (x); i = (x); l = (x); \
> + C = (x); S = (x); I = (x); L = (x); \
> + printf(FMT, c, s, i, l, C, S, I, L)
> +
> +#ifdef USE_AS_D_SCRIPT
> +BEGIN
> +#else
> +int main(int c_unused, char **v_unused)
> +#endif
> +{
> + /* from scalar */
> + TEST(-2);
> + TEST(0xfffffffffffffffe);
> + TEST(0xfffffffe);
> + TEST(0xfffe);
> + TEST(0xfe);
> + TEST(2);
> + TEST(0x55);
> + TEST(0x5555);
> + TEST(0x55555555);
> + TEST(0x5555555555555555);
> +
> + /* from signed char */
> + c0 = -2; TEST(c0);
> + c0 = 0xfe; TEST(c0);
> + c0 = 2; TEST(c0);
> + c0 = 0x55; TEST(c0);
> +
> + /* from short */
> + s0 = -2; TEST(s0);
> + s0 = 0xfffe; TEST(s0);
> + s0 = 2; TEST(s0);
> + s0 = 0x5555; TEST(s0);
> +
> + /* from int */
> + i0 = -2; TEST(i0);
> + i0 = 0xfffffffe; TEST(i0);
> + i0 = 2; TEST(i0);
> + i0 = 0x55555555; TEST(i0);
> +
> + /* from long long */
> + l0 = -2; TEST(l0);
> + l0 = 0xfffffffffffffffe; TEST(l0);
> + l0 = 2; TEST(l0);
> + l0 = 0x5555555555555555; TEST(l0);
> +
> + /* from unsigned char */
> + C0 = -2; TEST(C0);
> + C0 = 0xfe; TEST(C0);
> + C0 = 2; TEST(C0);
> + C0 = 0x55; TEST(C0);
> +
> + /* from unsigned short */
> + S0 = -2; TEST(S0);
> + S0 = 0xfffe; TEST(S0);
> + S0 = 2; TEST(S0);
> + S0 = 0x5555; TEST(S0);
> +
> + /* from unsigned int */
> + I0 = -2; TEST(I0);
> + I0 = 0xfffffffe; TEST(I0);
> + I0 = 2; TEST(I0);
> + I0 = 0x55555555; TEST(I0);
> +
> + /* from unsigned long long */
> + L0 = -2; TEST(L0);
> + L0 = 0xfffffffffffffffe; TEST(L0);
> + L0 = 2; TEST(L0);
> + L0 = 0x5555555555555555; TEST(L0);
> +
> +#ifdef USE_AS_D_SCRIPT
> + exit (0);
> +#else
> + return 0;
> +#endif
> +}
> diff --git a/test/unittest/arithmetic/tst.cast-imp.r b/test/unittest/arithmetic/tst.cast-imp.r
> new file mode 100644
> index 00000000..0ae3e3f1
> --- /dev/null
> +++ b/test/unittest/arithmetic/tst.cast-imp.r
> @@ -0,0 +1,43 @@
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +-2 -2 -2 4294967294 254 65534 4294967294 4294967294
> +-2 -2 65534 65534 254 65534 65534 65534
> +-2 254 254 254 254 254 254 254
> +2 2 2 2 2 2 2 2
> +85 85 85 85 85 85 85 85
> +85 21845 21845 21845 85 21845 21845 21845
> +85 21845 1431655765 1431655765 85 21845 1431655765 1431655765
> +85 21845 1431655765 6148914691236517205 85 21845 1431655765 6148914691236517205
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +2 2 2 2 2 2 2 2
> +85 85 85 85 85 85 85 85
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +2 2 2 2 2 2 2 2
> +85 21845 21845 21845 85 21845 21845 21845
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +2 2 2 2 2 2 2 2
> +85 21845 1431655765 1431655765 85 21845 1431655765 1431655765
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +2 2 2 2 2 2 2 2
> +85 21845 1431655765 6148914691236517205 85 21845 1431655765 6148914691236517205
> +-2 254 254 254 254 254 254 254
> +-2 254 254 254 254 254 254 254
> +2 2 2 2 2 2 2 2
> +85 85 85 85 85 85 85 85
> +-2 -2 65534 65534 254 65534 65534 65534
> +-2 -2 65534 65534 254 65534 65534 65534
> +2 2 2 2 2 2 2 2
> +85 21845 21845 21845 85 21845 21845 21845
> +-2 -2 -2 4294967294 254 65534 4294967294 4294967294
> +-2 -2 -2 4294967294 254 65534 4294967294 4294967294
> +2 2 2 2 2 2 2 2
> +85 21845 1431655765 1431655765 85 21845 1431655765 1431655765
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +-2 -2 -2 -2 254 65534 4294967294 18446744073709551614
> +2 2 2 2 2 2 2 2
> +85 21845 1431655765 6148914691236517205 85 21845 1431655765 6148914691236517205
> +
> --
> 2.18.4
>
>
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