176 lines
6.5 KiB
Diff
176 lines
6.5 KiB
Diff
From f469e8ce11672e26feb5ba6f9a134275fcfd5b4f Mon Sep 17 00:00:00 2001
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From: Sergio Durigan Junior <sergiodj@redhat.com>
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Date: Fri, 21 Aug 2015 18:13:46 -0400
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Subject: [PATCH 1/4] Improve error reporting when handling SystemTap SDT
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probes
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This patch improves the error reporting when handling SystemTap SDT
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probes. "Handling", in this case, mostly means "parsing".
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On gdb/probe.h, only trivial changes on functions' comments in order
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to explicitly mention that some of them can throw exceptions. This is
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just to make the API a bit more clear.
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On gdb/stap-probe.c, I have s/internal_error/error/ on two functions
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that are responsible for parsing specific bits of the probes'
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arguments: stap_get_opcode and stap_get_expected_argument_type. It is
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not correct to call internal_error on such situations because it is
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not really GDB's fault if the probes have malformed arguments. I also
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improved the error reported on stap_get_expected_argument_type by also
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including the probe name on it.
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Aside from that, and perhaps most importantly, I added a check on
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stap_get_arg to make sure that we don't try to extract an argument
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from a probe that has no arguments. This check issues an
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internal_error, because it really means that GDB is doing something it
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shouldn't.
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Although it can be considered almost trivial, and despite the fact
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that I am the maintainer for this part of the code, I am posting this
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patch for review. I will wait a few days, and if nobody has anything
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to say, I will go ahead and push it.
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gdb/ChangeLog:
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2015-09-01 Sergio Durigan Junior <sergiodj@redhat.com>
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* probe.h (struct probe_ops) <get_probe_argument_count,
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evaluate_probe_argument, enable_probe, disable_probe>: Mention in
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the comment that the function can throw an exception.
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(get_probe_argument_count): Likewise.
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(evaluate_probe_argument): Likewise.
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* stap-probe.c (stap_get_opcode): Call error instead of
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internal_error.
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(stap_get_expected_argument_type): Likewise. Add argument
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'probe'. Improve error message by mentioning the probe's name.
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(stap_parse_probe_arguments): Adjust call to
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stap_get_expected_argument_type.
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(stap_get_arg): Add comment. Assert that 'probe->args_parsed' is
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not zero. Call internal_error if GDB requests an argument but the
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probe has no arguments.
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---
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gdb/ChangeLog | 17 +++++++++++++++++
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gdb/probe.h | 20 ++++++++++++++------
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gdb/stap-probe.c | 29 ++++++++++++++++++++++-------
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3 files changed, 53 insertions(+), 13 deletions(-)
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Index: gdb-7.9.1/gdb/probe.h
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===================================================================
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--- gdb-7.9.1.orig/gdb/probe.h
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+++ gdb-7.9.1/gdb/probe.h
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@@ -70,7 +70,8 @@ struct probe_ops
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CORE_ADDR (*get_probe_address) (struct probe *probe,
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struct objfile *objfile);
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- /* Return the number of arguments of PROBE. */
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+ /* Return the number of arguments of PROBE. This function can
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+ throw an exception. */
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unsigned (*get_probe_argument_count) (struct probe *probe,
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struct frame_info *frame);
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@@ -82,7 +83,8 @@ struct probe_ops
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int (*can_evaluate_probe_arguments) (struct probe *probe);
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/* Evaluate the Nth argument from the PROBE, returning a value
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- corresponding to it. The argument number is represented N. */
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+ corresponding to it. The argument number is represented N.
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+ This function can throw an exception. */
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struct value *(*evaluate_probe_argument) (struct probe *probe,
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unsigned n,
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@@ -246,7 +248,9 @@ extern struct cmd_list_element **info_pr
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extern CORE_ADDR get_probe_address (struct probe *probe,
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struct objfile *objfile);
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-/* Return the argument count of the specified probe. */
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+/* Return the argument count of the specified probe.
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+
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+ This function can throw an exception. */
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extern unsigned get_probe_argument_count (struct probe *probe,
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struct frame_info *frame);
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@@ -258,7 +262,9 @@ extern unsigned get_probe_argument_count
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extern int can_evaluate_probe_arguments (struct probe *probe);
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/* Evaluate argument N of the specified probe. N must be between 0
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- inclusive and get_probe_argument_count exclusive. */
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+ inclusive and get_probe_argument_count exclusive.
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+
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+ This function can throw an exception. */
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extern struct value *evaluate_probe_argument (struct probe *probe,
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unsigned n,
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Index: gdb-7.9.1/gdb/stap-probe.c
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===================================================================
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--- gdb-7.9.1.orig/gdb/stap-probe.c
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+++ gdb-7.9.1/gdb/stap-probe.c
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@@ -313,9 +313,8 @@ stap_get_opcode (const char **s)
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break;
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default:
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- internal_error (__FILE__, __LINE__,
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- _("Invalid opcode in expression `%s' for SystemTap"
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- "probe"), *s);
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+ error (_("Invalid opcode in expression `%s' for SystemTap"
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+ "probe"), *s);
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}
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return op;
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@@ -326,7 +325,8 @@ stap_get_opcode (const char **s)
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static struct type *
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stap_get_expected_argument_type (struct gdbarch *gdbarch,
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- enum stap_arg_bitness b)
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+ enum stap_arg_bitness b,
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+ const struct stap_probe *probe)
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{
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switch (b)
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{
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@@ -361,8 +361,8 @@ stap_get_expected_argument_type (struct
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return builtin_type (gdbarch)->builtin_uint64;
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default:
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- internal_error (__FILE__, __LINE__,
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- _("Undefined bitness for probe."));
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+ error (_("Undefined bitness for probe '%s'."),
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+ probe->p.name);
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break;
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}
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}
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@@ -1172,7 +1172,8 @@ stap_parse_probe_arguments (struct stap_
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else
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arg.bitness = STAP_ARG_BITNESS_UNDEFINED;
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- arg.atype = stap_get_expected_argument_type (gdbarch, arg.bitness);
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+ arg.atype = stap_get_expected_argument_type (gdbarch, arg.bitness,
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+ probe);
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expr = stap_parse_argument (&cur, arg.atype, gdbarch);
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@@ -1278,12 +1279,26 @@ stap_is_operator (const char *op)
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return ret;
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}
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+/* Return argument N of probe PROBE.
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+
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+ If the probe's arguments have not been parsed yet, parse them. If
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+ there are no arguments, throw an exception (error). Otherwise,
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+ return the requested argument. */
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+
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static struct stap_probe_arg *
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stap_get_arg (struct stap_probe *probe, unsigned n, struct gdbarch *gdbarch)
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{
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if (!probe->args_parsed)
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stap_parse_probe_arguments (probe, gdbarch);
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+ gdb_assert (probe->args_parsed);
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+ if (probe->args_u.vec == NULL)
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+ internal_error (__FILE__, __LINE__,
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+ _("Probe '%s' apparently does not have arguments, but \n"
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+ "GDB is requesting its argument number %u anyway. "
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+ "This should not happen. Please report this bug."),
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+ probe->p.name, n);
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+
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return VEC_index (stap_probe_arg_s, probe->args_u.vec, n);
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}
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