From: "dsmith at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug translator/21173] New: odd translator behavior with overloaded functions
Date: Thu, 16 Feb 2017 19:01:00 -0000 [thread overview]
Message-ID: <bug-21173-6586@http.sourceware.org/bugzilla/> (raw)
https://sourceware.org/bugzilla/show_bug.cgi?id=21173
Bug ID: 21173
Summary: odd translator behavior with overloaded functions
Product: systemtap
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: translator
Assignee: systemtap at sourceware dot org
Reporter: dsmith at redhat dot com
Target Milestone: ---
Since bug #18431, the translator supports overloaded functions (2 functions
with the same name but different parameters). However, in certain situations,
this isn't acting correctly.
Here's a test script:
====
function foo:long(a:long, b:long)
{
return (a + b)
}
function foo:string(a:long, b:string, c:long)
{
return sprintf("%s %d", b, a + c)
}
probe begin
{
println(__inode_vfsmount(1))
println(foo(1, 2, 3))
}
====
====
stap --compatible=2.9 -vp4 ../src/test.stp
Pass 1: parsed user script and 465 library scripts using
135824virt/44664res/7380shr/37236data kb, in 240usr/50sys/293real ms.
WARNING: Eliding unused function 'foo': identifier 'foo' at
../src/test.stp:1:10
source: function foo:long(a:long, b:long)
^
semantic error: unknown type in dereference: operator '&' at
/usr/local/share/systemtap/tapset/linux/dentry.stp:93:24
source: head = &sb->s_mounts
^
Pass 2: analyzed script: 1 probe, 8 functions, 3 embeds, 0 globals using
285440virt/195264res/8548shr/186852data kb, in 1830usr/320sys/2167real ms.
Pass 2: analysis failed. [man error::pass2]
=====
There are at least 3 problems with that translator output:
- It doesn't warn/error on the fact the 'foo' function variants has 2 different
return values.
- Somehow this causes @cast() type errors to appear elsewhere.
- It doesn't realize that there is no overload that takes 3 longs.
It is possible the translator found the error earlier, but its message was
suppressed and it incidentally resulted in shortcuting some other processing
leading the @cast() or whatever to never be attempted.
Note that if the 'foo' function call is fixed to call either function
correctly, the script compiles just fine without any @cast-type errors. Also
note that I found this while debugging a systemtap.stress/tapset_functions.exp
failure.
--
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next reply other threads:[~2017-02-16 19:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-16 19:01 dsmith at redhat dot com [this message]
2017-02-20 18:37 ` [Bug translator/21173] " dsmith at redhat dot com
2017-02-20 18:41 ` dsmith at redhat dot com
2017-02-20 21:16 ` dsmith at redhat dot com
2017-02-20 22:47 ` dsmith at redhat dot com
2020-11-14 18:43 ` fche at redhat dot com
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