On 3/29/20 12:51 AM, Martin Sebor wrote:
On 3/26/20 3:40 AM, Martin Liška wrote:
Hi.
I'm suggesting to provide a warning when one uses -flto=jobserver
but we can't detect job server for some reason.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed in next stage1?
Thanks,
Martin
gcc/ChangeLog:
2020-03-26 Martin Liska <mli...@suse.cz>
PR driver/94330
* lto-wrapper.c (run_gcc): When using -flto=jobserver,
report warning when the jobserver is not detected.
Sounds like a useful warning. It would be even better if it said why.
jobserver_active_p() returns false under one of at least three distinct
conditions. If the function provided a status string in addition to
the boolean result, the string could be included in the text of
the warning.
As an aside, I'd expect -Wformat-diag to complain about the trailing
period:
+ warning (0, "jobserver is not available.");
Martin
Hello.
I like the suggested improvement, there's updated patch that I've just
tested.
Martin
>From 2efd69ac2282ba42755826d265bae09900e9ce0c Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Thu, 26 Mar 2020 09:57:35 +0100
Subject: [PATCH] Provide warning for missing jobserver.
gcc/ChangeLog:
2020-03-26 Martin Liska <mli...@suse.cz>
PR driver/94330
* lto-wrapper.c (run_gcc): When using -flto=jobserver,
report warning when the jobserver is not detected.
---
gcc/lto-wrapper.c | 39 +++++++++++++++++++++++++--------------
1 file changed, 25 insertions(+), 14 deletions(-)
diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c
index 46a88b233f6..19d0c224dad 100644
--- a/gcc/lto-wrapper.c
+++ b/gcc/lto-wrapper.c
@@ -1236,28 +1236,33 @@ init_num_threads (void)
/* FIXME: once using -std=c++11, we can use std::thread::hardware_concurrency. */
-/* Return true when a jobserver is running and can accept a job. */
+/* Test and return reason why a jobserver cannot be detected. */
-static bool
+static const char *
jobserver_active_p (void)
{
+ #define JS_PREFIX "jobserver is not available: "
+ #define JS_NEEDLE "--jobserver-auth="
+
const char *makeflags = getenv ("MAKEFLAGS");
if (makeflags == NULL)
- return false;
+ return JS_PREFIX "%<MAKEFLAGS%> environment variable is unset";
- const char *needle = "--jobserver-auth=";
- const char *n = strstr (makeflags, needle);
+ const char *n = strstr (makeflags, JS_NEEDLE);
if (n == NULL)
- return false;
+ return JS_PREFIX "%<" JS_NEEDLE "%> is not present in %<MAKEFLAGS%>";
int rfd = -1;
int wfd = -1;
- return (sscanf (n + strlen (needle), "%d,%d", &rfd, &wfd) == 2
- && rfd > 0
- && wfd > 0
- && is_valid_fd (rfd)
- && is_valid_fd (wfd));
+ if (sscanf (n + strlen (JS_NEEDLE), "%d,%d", &rfd, &wfd) == 2
+ && rfd > 0
+ && wfd > 0
+ && is_valid_fd (rfd)
+ && is_valid_fd (wfd))
+ return NULL;
+ else
+ return JS_PREFIX "cannot access %<" JS_NEEDLE "%> file descriptors";
}
/* Execute gcc. ARGC is the number of arguments. ARGV contains the arguments. */
@@ -1473,10 +1478,16 @@ run_gcc (unsigned argc, char *argv[])
auto_parallel = 0;
parallel = 0;
}
- else if (!jobserver && jobserver_active_p ())
+ else
{
- parallel = 1;
- jobserver = 1;
+ const char *jobserver_error = jobserver_active_p ();
+ if (jobserver && jobserver_error != NULL)
+ warning (0, jobserver_error);
+ else if (!jobserver && jobserver_error == NULL)
+ {
+ parallel = 1;
+ jobserver = 1;
+ }
}
if (linker_output)
--
2.26.0
