[DTrace-devel] [PATCH] Introduce -xdisasm=n option
Eugene Loh
eugene.loh at oracle.com
Wed Apr 8 14:40:07 PDT 2020
On 04/08/2020 08:00 AM, Kris Van Hees wrote:
> In order to prepare for more functionality for the disassembler in
> DTrace, an option is being added to be able to specify a bitmap that
> indicates which disassembly listings the user wishes to have printed
> if '-S' is supplied as command line option.
>
> The default is 1 which indicates that the disassembler listing should
> be printed after program compilation.
>
> The comment describing -xdisasm=n documents two additional bits that
> are not yet implemented:
>
> 2 = disassembler listing after the program is linked
> 3 = disassembler listing right before loading the program
Need a consistent way of talking about these things. Since you call it
a bitmap and because that's what the user will specify (in order to be
able to specify multiple bits with a single argument), best (correct?)
to say the choices are 1, 2, and 4. So, change 3 to 4.
I don't know if calling them 0x1, 0x2, and 0x4 helps readers recognize
these things as masks.
Someday need tests for this option.
> Since the vlaue supplied to -xdisasm is a bitmap, any combination of
vlaue
->
value
More below.
> disassembler listings can be requested.
>
> Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> ---
> libdtrace/dt_cc.c | 30 ++++++++++++++++++------------
> libdtrace/dt_impl.h | 14 ++++++++++++++
> libdtrace/dt_open.c | 1 +
> libdtrace/dt_options.c | 16 +++++++++++++++-
> 4 files changed, 48 insertions(+), 13 deletions(-)
>
> diff --git a/libdtrace/dt_cc.c b/libdtrace/dt_cc.c
> index ab987fc7..c8c6dd0c 100644
> --- a/libdtrace/dt_cc.c
> +++ b/libdtrace/dt_cc.c
> @@ -2184,12 +2184,15 @@ dtrace_program_strcompile(dtrace_hdl_t *dtp, const char *s,
> {
> dtrace_prog_t *rv;
>
> - if ((rv = dt_compile(dtp, DT_CTX_DPROG,
> - spec, NULL, cflags, argc, argv, NULL, s)) != NULL) {
> - if (cflags & DTRACE_C_DIFV)
> - dt_dis_program(dtp, rv, stderr);
> - }
> - return (rv);
> + rv = dt_compile(dtp, DT_CTX_DPROG, spec, NULL, cflags,
> + argc, argv, NULL, s);
> + if (rv == NULL)
> + return NULL;
> +
> + if (cflags & DTRACE_C_DIFV && DT_DISASM(dtp, 1))
> + dt_dis_program(dtp, rv, stderr);
> +
> + return rv;
> }
>
> dtrace_prog_t *
> @@ -2198,12 +2201,15 @@ dtrace_program_fcompile(dtrace_hdl_t *dtp, FILE *fp,
> {
> dtrace_prog_t *rv;
>
> - if ((rv = dt_compile(dtp, DT_CTX_DPROG,
> - DTRACE_PROBESPEC_NAME, NULL, cflags, argc, argv, fp, NULL)) != NULL) {
> - if (cflags & DTRACE_C_DIFV)
> - dt_dis_program(dtp, rv, stderr);
> - }
> - return (rv);
> + rv = dt_compile(dtp, DT_CTX_DPROG, DTRACE_PROBESPEC_NAME, NULL, cflags,
> + argc, argv, fp, NULL);
> + if (rv == NULL)
> + return NULL;
> +
> + if (cflags & DTRACE_C_DIFV && DT_DISASM(dtp, 1))
> + dt_dis_program(dtp, rv, stderr);
> +
> + return rv;
> }
>
> int
> diff --git a/libdtrace/dt_impl.h b/libdtrace/dt_impl.h
> index 536b1745..ca8b7851 100644
> --- a/libdtrace/dt_impl.h
> +++ b/libdtrace/dt_impl.h
> @@ -326,6 +326,7 @@ struct dtrace_hdl {
> uint_t dt_xlatemode; /* dtrace translator linking mode (see below) */
> uint_t dt_stdcmode; /* dtrace stdc compatibility mode (see below) */
> uint_t dt_treedump; /* dtrace tree debug bitmap (see below) */
> + uint_t dt_disasm; /* dtrace disassembler bitmap (see below) */
> uint64_t dt_options[DTRACEOPT_MAX]; /* dtrace run-time options */
> int dt_version; /* library version requested by client */
> int dt_ctferr; /* error resulting from last CTF failure */
> @@ -413,6 +414,19 @@ struct dtrace_hdl {
> */
> #define DT_TREEDUMP_PASS(dtp, p) ((dtp)->dt_treedump & (1 << ((p) - 1)))
>
> +/*
> + * Macro to test whether a given disassembler bit is set in the dt_disasm
> + * bit-vector. If the bit for mode 'm' is set, the D disassembler will be
> + * invoked for that specific mode. The '-S' option must also be supplied in
> + * order for disassembler output to be generated.
> + *
> + * Supported modes are:
> + * 0 Print disassembler listing for each compiled clause.
> + * 1 Print disassembler listing for the final linked program.
> + * 2 Print disassembler listing for the program right before loading.
Instead of 0, 1, and 2, call them 1, 2, and 4 (or even prefix with 0x
per above suggestion if you like).
> + */
> +#define DT_DISASM(dtp, m) ((dtp)->dt_disasm & (1 << ((m) - 1)))
> +
(1 << ((m) - 1)))
becomes simply
(m)
> /*
> * Macros for accessing the cached CTF container and type ID for the common
> * types "int", "string", and <DYN>, which we need to use frequently in the D
> diff --git a/libdtrace/dt_open.c b/libdtrace/dt_open.c
> index 6b0ba71d..ab60a803 100644
> --- a/libdtrace/dt_open.c
> +++ b/libdtrace/dt_open.c
> @@ -709,6 +709,7 @@ dt_vopen(int version, int flags, int *errp,
> dtp->dt_linktype = DT_LTYP_ELF;
> dtp->dt_xlatemode = DT_XL_STATIC;
> dtp->dt_stdcmode = DT_STDC_XA;
> + dtp->dt_disasm = 1;
> dtp->dt_version = version;
> dtp->dt_cdefs_fd = -1;
> dtp->dt_ddefs_fd = -1;
> diff --git a/libdtrace/dt_options.c b/libdtrace/dt_options.c
> index a199cfdb..8c6e0e42 100644
> --- a/libdtrace/dt_options.c
> +++ b/libdtrace/dt_options.c
> @@ -397,6 +397,19 @@ dt_opt_module_path(dtrace_hdl_t *dtp, const char *arg, uintptr_t option)
> return (0);
> }
>
> +/*ARGSUSED*/
> +static int
> +dt_opt_disasm(dtrace_hdl_t *dtp, const char *arg, uintptr_t option)
> +{
> + int m;
> +
> + if (arg == NULL || (m = atoi(arg)) <= 0)
> + return (dt_set_errno(dtp, EDT_BADOPTVAL));
> +
> + dtp->dt_disasm = m;
> + return (0);
> +}
> +
> /*ARGSUSED*/
> static int
> dt_opt_evaltime(dtrace_hdl_t *dtp, const char *arg, uintptr_t option)
> @@ -1032,11 +1045,12 @@ static const dt_option_t _dtrace_ctoptions[] = {
> { "ctypes", dt_opt_ctypes },
> { "ctfpath", dt_opt_ctfa_path },
> { "defaultargs", dt_opt_cflags, DTRACE_C_DEFARG },
> - { "dtypes", dt_opt_dtypes },
> { "debug", dt_opt_debug },
> { "debugassert", dt_opt_debug_assert },
> { "define", dt_opt_cpp_opts, (uintptr_t)"-D" },
> + { "disasm", dt_opt_disasm },
> { "droptags", dt_opt_droptags },
> + { "dtypes", dt_opt_dtypes },
> { "empty", dt_opt_cflags, DTRACE_C_EMPTY },
> { "errtags", dt_opt_cflags, DTRACE_C_ETAGS },
> { "evaltime", dt_opt_evaltime },
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