From: Pedro Alves <pedro@palves.net>
To: Simon Marchi <simark@simark.ca>, gdb-patches@sourceware.org
Subject: [PATCH v3] enum_flags to_string (was: Re: [PATCH v2 07/29] Thread options & clone events (core + remote))
Date: Fri, 28 Oct 2022 12:08:46 +0100 [thread overview]
Message-ID: <6b91f8f6-d3b5-c44b-297c-ce1c3a1c80f6@palves.net> (raw)
In-Reply-To: <acdc943e-695f-a36d-059a-6b935a45d0f1@palves.net>
On 2022-10-28 11:26 a.m., Pedro Alves wrote:
> Some self review. :-)
>
> On 2022-10-27 8:55 p.m., Pedro Alves wrote:
>
>>
>> static std::string
>> to_string (some_flags flags)
>> {
>> #define CASE(X) { X, #X }
>> static constexpr test_flags::string_map_element mapping[] = {
>> CASE (SOME_FLAG1),
>> CASE (SOME_FLAG2),
>> CASE (SOME_FLAG3),
>> };
>> #undef CASE
>>
>> return flags.to_string (mapping);
>> }
>
> I was looking at this again, and noticed I named the macro "CASE". That's just
> because that style of macro is typically used in a switch/case, my first approach
> used one. That isn't what's being done in the end, so better rename it. And while doing that,
> I realized that you don't even need to name the array or its type. Like so:
>
> static std::string
> to_string (some_flags flags)
> {
> #define MAP_ENUM_FLAG(X) { X, #X }
> return flags.to_string ({
> MAP_ENUM_FLAG (SOME_FLAG1),
> MAP_ENUM_FLAG (SOME_FLAG3),
> });
> #undef MAP_ENUM_FLAG
> }
>
> But then, every enum_flags to_string implementation will end up defining/undefining that
> same macro, so might as well put it in gdbsupport/enum-flags.h, resulting in:
>
> static std::string
> to_string (test_flags flags)
> {
> return flags.to_string ({
> MAP_ENUM_FLAG (FLAG1),
> MAP_ENUM_FLAG (FLAG3),
> });
> }
Bah, I now looked at the generated code at -O2, and with the unnamed array, the compiler
emits code to manually compose a temporary array on the stack at every call...
3rd time's a charm?
-- >8 --
From 0fe3edef69360c6795ab6811c4f3cba06159a50d Mon Sep 17 00:00:00 2001
From: Pedro Alves <pedro@palves.net>
Date: Tue, 25 Oct 2022 15:39:37 +0100
Subject: [PATCH] enum_flags to_string
This commit introduces shared infrastructure that can be used to
implement enum_flags -> to_string functions. With this, if we want to
support converting a given enum_flags specialization to string, we
just need to implement a function that provides the enumerator->string
mapping, like so:
enum some_flag
{
SOME_FLAG1 = 1 << 0,
SOME_FLAG2 = 1 << 1,
SOME_FLAG3 = 1 << 2,
};
DEF_ENUM_FLAGS_TYPE (some_flag, some_flags);
static std::string
to_string (some_flags flags)
{
static constexpr some_flags::string_mapping mapping[] = {
MAP_ENUM_FLAG (SOME_FLAG1),
MAP_ENUM_FLAG (SOME_FLAG2),
MAP_ENUM_FLAG (SOME_FLAG3),
};
return flags.to_string (mapping);
}
.. and then to_string(SOME_FLAG2 | SOME_FLAG3) produces a string like
"0x6 [SOME_FLAG2 SOME_FLAG3]".
If we happen to forget to update the mapping array when we introduce a
new enumerator, then the string representation will pretty-print the
flags it knows about, and then the leftover flags in hex (one single
number). For example, if we had missed mapping SOME_FLAG2 above, we'd
end up with:
to_string(SOME_FLAG2 | SOME_FLAG3) => "0x6 [SOME_FLAG2 0x4]");
Other than in the unit tests included, no actual usage of the
functionality is added in this commit.
Change-Id: I835de43c33d13bc0c95132f42c3f97318b875779
---
gdb/unittests/enum-flags-selftests.c | 24 ++++++++++++
gdbsupport/enum-flags.h | 57 ++++++++++++++++++++++++++++
2 files changed, 81 insertions(+)
diff --git a/gdb/unittests/enum-flags-selftests.c b/gdb/unittests/enum-flags-selftests.c
index f52fc7220a1..ef43ba23cdf 100644
--- a/gdb/unittests/enum-flags-selftests.c
+++ b/gdb/unittests/enum-flags-selftests.c
@@ -374,6 +374,20 @@ enum test_uflag : unsigned
DEF_ENUM_FLAGS_TYPE (test_flag, test_flags);
DEF_ENUM_FLAGS_TYPE (test_uflag, test_uflags);
+/* to_string enumerator->string mapping function used to test
+ enum_flags::to_string. This intentionally misses mapping one
+ enumerator (FLAG2). */
+
+static std::string
+to_string (test_flags flags)
+{
+ static constexpr test_flags::string_mapping mapping[] = {
+ MAP_ENUM_FLAG (FLAG1),
+ MAP_ENUM_FLAG (FLAG3),
+ };
+ return flags.to_string (mapping);
+}
+
static void
self_test ()
{
@@ -581,6 +595,16 @@ self_test ()
SELF_CHECK (ok);
}
+
+ /* Check string conversion. */
+ {
+ SELF_CHECK (to_string (0) == "0x0 []");
+ SELF_CHECK (to_string (FLAG1) == "0x2 [FLAG1]");
+ SELF_CHECK (to_string (FLAG1 | FLAG3) == "0xa [FLAG1 FLAG3]");
+ SELF_CHECK (to_string (FLAG1 | FLAG2 | FLAG3) == "0xe [FLAG1 FLAG3 0x4]");
+ SELF_CHECK (to_string (FLAG2) == "0x4 [0x4]");
+ SELF_CHECK (to_string (test_flag (0xff)) == "0xff [FLAG1 FLAG3 0xf5]");
+ }
}
} /* namespace enum_flags_tests */
diff --git a/gdbsupport/enum-flags.h b/gdbsupport/enum-flags.h
index cd500f55ff3..911f3fd7890 100644
--- a/gdbsupport/enum-flags.h
+++ b/gdbsupport/enum-flags.h
@@ -130,6 +130,17 @@ class enum_flags
typedef E enum_type;
typedef typename enum_underlying_type<enum_type>::type underlying_type;
+ /* For to_string. Maps one enumerator of E to a string. */
+ struct string_mapping
+ {
+ E flag;
+ const char *str;
+ };
+
+ /* Convenience for to_string implementations, to build a
+ string_mapping array. */
+#define MAP_ENUM_FLAG(ENUM_FLAG) { ENUM_FLAG, #ENUM_FLAG }
+
public:
/* Allow default construction. */
constexpr enum_flags ()
@@ -183,6 +194,52 @@ class enum_flags
/* Binary operations involving some unrelated type (which would be a
bug) are implemented as non-members, and deleted. */
+ /* Convert this object to a std::string, using MAPPING as
+ enumerator-to-string mapping array. This is not meant to be
+ called directly. Instead, enum_flags specializations should have
+ their own to_string function wrapping this one, thus hidding the
+ mapping array from callers. */
+
+ template<size_t N>
+ std::string
+ to_string (const string_mapping (&mapping)[N]) const
+ {
+ enum_type flags = raw ();
+ std::string res = hex_string (flags);
+ res += " [";
+
+ bool need_space = false;
+ for (const auto &entry : mapping)
+ {
+ if ((flags & entry.flag) != 0)
+ {
+ /* Do op~ in the underlying type, because if enum_type's
+ underlying type is signed, op~ won't be defined for
+ it. */
+ flags &= (enum_type) ~(underlying_type) entry.flag;
+
+ if (need_space)
+ res += " ";
+ res += entry.str;
+
+ need_space = true;
+ }
+ }
+
+ /* If there were flags not included in the mapping, print them as
+ a hex number. */
+ if (flags != 0)
+ {
+ if (need_space)
+ res += " ";
+ res += hex_string (flags);
+ }
+
+ res += "]";
+
+ return res;
+ }
+
private:
/* Stored as enum_type because GDB knows to print the bit flags
neatly if the enum values look like bit flags. */
base-commit: 508ccf9b3e1db355037a4a1c9004efe0d6d3ffbf
--
2.36.0
next prev parent reply other threads:[~2022-10-28 11:08 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 22:24 [PATCH v2 00/29] Step over thread clone and thread exit Pedro Alves
2022-07-13 22:24 ` [PATCH v2 01/29] displaced step: pass down target_waitstatus instead of gdb_signal Pedro Alves
2022-07-20 20:21 ` Simon Marchi
2022-07-13 22:24 ` [PATCH v2 02/29] linux-nat: introduce pending_status_str Pedro Alves
2022-07-20 20:38 ` Simon Marchi
2022-07-13 22:24 ` [PATCH v2 03/29] gdb/linux: Delete all other LWPs immediately on ptrace exec event Pedro Alves
2022-07-21 0:45 ` Simon Marchi
2022-07-13 22:24 ` [PATCH v2 04/29] Step over clone syscall w/ breakpoint, TARGET_WAITKIND_THREAD_CLONED Pedro Alves
2022-07-21 1:35 ` Simon Marchi
2022-10-17 18:54 ` Pedro Alves
2022-10-18 12:40 ` [PATCH] Don't explicitly set clone child ptrace options (was: Re: [PATCH v2 04/29] Step over clone syscall w/ breakpoint, TARGET_WAITKIND_THREAD_CLONED) Pedro Alves
2022-10-28 14:50 ` Simon Marchi
2022-12-12 20:13 ` [PATCH v2 04/29] Step over clone syscall w/ breakpoint, TARGET_WAITKIND_THREAD_CLONED Pedro Alves
2022-07-13 22:24 ` [PATCH v2 05/29] Support clone events in the remote protocol Pedro Alves
2022-07-21 2:25 ` Simon Marchi
2022-12-12 20:14 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 06/29] Avoid duplicate QThreadEvents packets Pedro Alves
2022-07-21 2:30 ` Simon Marchi
2022-12-12 20:14 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 07/29] Thread options & clone events (core + remote) Pedro Alves
2022-07-21 3:14 ` Simon Marchi
2022-10-27 19:55 ` [PATCH] enum_flags to_string (was: Re: [PATCH v2 07/29] Thread options & clone events (core + remote)) Pedro Alves
2022-10-28 10:26 ` [PATCH v2] " Pedro Alves
2022-10-28 11:08 ` Pedro Alves [this message]
2022-10-28 15:59 ` [PATCH v3] " Simon Marchi
2022-10-28 18:23 ` Pedro Alves
2022-10-31 12:47 ` Simon Marchi
2022-11-07 17:26 ` [PATCH v5] " Pedro Alves
2022-11-07 18:29 ` Simon Marchi
2022-11-08 14:56 ` Pedro Alves
2022-12-12 20:15 ` [PATCH v2 07/29] Thread options & clone events (core + remote) Pedro Alves
2022-07-13 22:24 ` [PATCH v2 08/29] Thread options & clone events (native Linux) Pedro Alves
2022-07-21 12:38 ` Simon Marchi
2022-12-12 20:16 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 09/29] Thread options & clone events (Linux GDBserver) Pedro Alves
2022-07-21 13:11 ` Simon Marchi
2022-12-12 20:16 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 10/29] gdbserver: Hide and don't detach pending clone children Pedro Alves
2022-07-13 22:24 ` [PATCH v2 11/29] Remove gdb/19675 kfails (displaced stepping + clone) Pedro Alves
2022-07-13 22:24 ` [PATCH v2 12/29] Add test for stepping over clone syscall Pedro Alves
2022-07-13 22:24 ` [PATCH v2 13/29] all-stop/synchronous RSP support thread-exit events Pedro Alves
2022-07-13 22:24 ` [PATCH v2 14/29] gdbserver/linux-low.cc: Ignore event_ptid if TARGET_WAITKIND_IGNORE Pedro Alves
2022-07-13 22:24 ` [PATCH v2 15/29] Introduce GDB_TO_EXIT thread option, fix step-over-thread-exit Pedro Alves
2022-07-13 22:24 ` [PATCH v2 16/29] Implement GDB_TO_EXIT support for Linux GDBserver Pedro Alves
2022-07-13 22:24 ` [PATCH v2 17/29] Implement GDB_TO_EXIT support for native Linux Pedro Alves
2022-07-21 15:26 ` Simon Marchi
2022-12-12 20:17 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 18/29] gdb: clear step over information on thread exit (PR gdb/27338) Pedro Alves
2022-07-21 18:12 ` Simon Marchi
2022-12-12 20:18 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 19/29] stop_all_threads: (re-)enable async before waiting for stops Pedro Alves
2022-07-21 18:21 ` Simon Marchi
2022-12-12 20:18 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 20/29] gdbserver: Queue no-resumed event after thread exit Pedro Alves
2022-07-13 22:24 ` [PATCH v2 21/29] Don't resume new threads if scheduler-locking is in effect Pedro Alves
2022-07-14 5:28 ` Eli Zaretskii
2022-07-21 18:49 ` Simon Marchi
2022-12-12 20:19 ` Pedro Alves
2022-07-13 22:24 ` [PATCH v2 22/29] Report thread exit event for leader if reporting thread exit events Pedro Alves
2022-07-13 22:24 ` [PATCH v2 23/29] Ignore failure to read PC when resuming Pedro Alves
2022-07-13 22:24 ` [PATCH v2 24/29] gdb/testsuite/lib/my-syscalls.S: Refactor new SYSCALL macro Pedro Alves
2022-07-13 22:24 ` [PATCH v2 25/29] Testcases for stepping over thread exit syscall (PR gdb/27338) Pedro Alves
2022-07-13 22:24 ` [PATCH v2 26/29] Document remote clone events, and QThreadOptions packet Pedro Alves
2022-07-14 5:27 ` Eli Zaretskii
2022-07-13 22:24 ` [PATCH v2 27/29] inferior::clear_thread_list always silent Pedro Alves
2022-07-13 22:24 ` [PATCH v2 28/29] Centralize "[Thread ...exited]" notifications Pedro Alves
2022-07-13 22:24 ` [PATCH v2 29/29] Cancel execution command on thread exit, when stepping, nexting, etc Pedro Alves
2022-07-21 19:28 ` [PATCH v2 00/29] Step over thread clone and thread exit Simon Marchi
2022-10-03 13:46 ` Tom de Vries
2022-10-03 18:37 ` Tom de Vries
2022-12-12 20:20 ` Pedro Alves
2022-12-12 20:19 ` Pedro Alves
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