Date: Sun, 05 Jan 2003 17:24:58 +0100 From: Poul-Henning Kamp <phk@freebsd.org> To: current@freebsd.org Subject: Calling gcc created constructors in the kernel... Message-ID: <7797.1041783898@critter.freebsd.dk>
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I want to get --test-coverage and --profile-arcs working for the
kernel in order to give us better statistical tools.
Unfortunately, GCC now uses construcorts to string the counters into
a list, and we don't call constructors in the kernel.
Would it be evil to do that ?
I've managed to get it working with the following patch, a modified
version of kernbb(8) and the standard GCC::gcov binary.
Any objections to me committing this ?
Is there a better way to get the start and end of the .ctors section ?
Poul-Henning
Index: conf/ldscript.i386
===================================================================
RCS file: /home/ncvs/src/sys/conf/ldscript.i386,v
retrieving revision 1.6
diff -u -r1.6 ldscript.i386
--- conf/ldscript.i386 11 Oct 2002 19:38:04 -0000 1.6
+++ conf/ldscript.i386 5 Jan 2003 13:50:12 -0000
@@ -65,10 +65,14 @@
CONSTRUCTORS
}
.data1 : { *(.data1) }
+ _start_ctors = .;
+ PROVIDE (start_ctors = .);
.ctors :
{
*(.ctors)
}
+ _stop_ctors = .;
+ PROVIDE (stop_ctors = .);
.dtors :
{
*(.dtors)
Index: kern/subr_prof.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_prof.c,v
retrieving revision 1.55
diff -u -r1.55 subr_prof.c
--- kern/subr_prof.c 1 Oct 2002 13:15:11 -0000 1.55
+++ kern/subr_prof.c 5 Jan 2003 13:53:38 -0000
@@ -78,6 +78,7 @@
}
#endif /* GUPROF */
+
/*
* Update the histograms to support extending the text region arbitrarily.
* This is done slightly naively (no sparse regions), so will waste slight
@@ -157,6 +158,7 @@
uintfptr_t tmp_addr;
#endif
+ tcov_init();
/*
* Round lowpc and highpc to multiples of the density we're using
* so the rest of the scaling (here and in gprof) stays in ints.
@@ -531,3 +533,24 @@
}
stopprofclock(p);
}
+
+#if 1
+typedef void (*ctor_t)(void);
+extern ctor_t _start_ctors, _stop_ctors;
+
+static void
+tcov_init(void *foo __unused)
+{
+ ctor_t *p, q;
+
+ printf("_start_ctors %p %p\n", _start_ctors, &_start_ctors);
+ printf("_stop_ctors %p %p\n", _stop_ctors, &_stop_ctors);
+ for (p = &_start_ctors; p < &_stop_ctors; p++) {
+ printf(" ctor %p %p\n", p, *p);
+ q = *p;
+ q();
+ }
+}
+
+SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_SECOND, tcov_init, NULL)
+#endif
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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