Thread overview
[Issue 19937] object._d_assert_fail linker error if compiling with -checkaction=context
Jun 03, 2019
JR
Aug 03, 2019
Seb
Aug 03, 2019
Seb
June 03, 2019
https://issues.dlang.org/show_bug.cgi?id=19937

--- Comment #1 from JR <zorael@gmail.com> ---
Apologies, I should mention Manjaro/Arch x86_64, dmd v2.086.0 from official repositories.

--
August 03, 2019
https://issues.dlang.org/show_bug.cgi?id=19937

Seb <greeenify@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |greeenify@gmail.com

--- Comment #2 from Seb <greeenify@gmail.com> ---
Demangled:

---
checkaction.o:checkaction.d:function const pure nothrow @nogc @trusted bool
std.uni.Trie!(std.uni.BitPacked!(bool, 1uL).BitPacked, dchar, 1114112uL,
std.uni.sliceBits!(13uL, 21uL).sliceBits, std.uni.sliceBits!(8uL,
13uL).sliceBits, std.uni.sliceBits!(0uL,
8uL).sliceBits).Trie.opIndex!().opIndex(dchar): error: undefined reference to
'pure nothrow @nogc @safe immutable(char)[] object._d_assert_fail!("<", ulong,
ulong)._d_assert_fail(ulong, ulong)'
---


Code generated from DMD looks like this:

```
inout pure nothrow @nogc @system BitPacked!(bool, 1LU) opIndex(ulong idx)
                        in
                        {
                                assert(idx < this.limit, _d_assert_fail(idx,
this.limit));
                        }
                        do
                        {
                                {
                                        {
                                                assert(idx < this.limit,
_d_assert_fail(idx, this.limit));
                                        }
                                }
                                return this.ptr.opIndex(this.ofs + idx);
                        }
```


...


```
_d_assert_fail!("<", ulong, ulong)
{
        pure nothrow @nogc @safe string _d_assert_fail(ulong a, ulong b)
        {
                import core.internal.dassert : invertCompToken,
miniFormatFakeAttributes, pureAlloc;
                string valA = miniFormatFakeAttributes(a);
                string valB = miniFormatFakeAttributes(b);
                enum string token = ">=";
                const const(ulong) totalLen = valA.length + 2LU + valB.length +
2LU;
                char[] buffer = cast(char[])pureAlloc(totalLen)[0..totalLen];
                ulong n = valA.length;
                buffer[0..n] = cast(const(char[]))valA;
                buffer[n++] = ' ';
                buffer[n..n + 2LU] = ">=";
                n += 2LU;
                buffer[n++] = ' ';
                buffer[n..n + valB.length] = cast(const(char[]))valB;
                return delegate () => cast(string)buffer();
        }

}
```

but it doesn't appear in the object file:

```
$ nm bar.o | grep assert_fail | ddemangle
0000000000000000 W pure nothrow @nogc @trusted immutable(char)[]
object._d_assert_fail!("<", uint, uint)._d_assert_fail(uint, uint).__lambda3()
0000000000000000 W pure nothrow @nogc @safe immutable(char)[]
object._d_assert_fail!("<", uint, uint)._d_assert_fail(uint, uint)
                 U pure nothrow @nogc @safe immutable(char)[]
object._d_assert_fail!("<", ulong, ulong)._d_assert_fail(ulong, ulong)
0000000000000000 W pure nothrow @nogc @trusted immutable(char)[]
object._d_assert_fail!(">=", uint, uint)._d_assert_fail(uint, uint).__lambda3()
0000000000000000 W pure nothrow @nogc @safe immutable(char)[]
object._d_assert_fail!(">=", uint, uint)._d_assert_fail(uint, uint)
```

DMD probably thinks that this assertion was already instantiated in Phobos (and thus should be part of the object file), but it is not as Phobos was build without -checkaction=context.

--
August 03, 2019
https://issues.dlang.org/show_bug.cgi?id=19937

--- Comment #3 from Seb <greeenify@gmail.com> ---
BTW a workaround is to do force the instantiation e.g. with the following hack:

```
cat << EOF > workaround.d
void test(ulong x, ulong y){
    assert(x < y);
}
EOF
```

```
dmd -checkaction=context -c workaround.d
dmd -checkaction=context workaround.o checkaction.d
```

--
February 24
https://issues.dlang.org/show_bug.cgi?id=19937

Mathias LANG <pro.mathias.lang@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pro.mathias.lang@gmail.com

--- Comment #4 from Mathias LANG <pro.mathias.lang@gmail.com> ---
I'm seeing this with anything that involves Vibe.d as well, with DMD v2.090.1.

--
February 24
https://issues.dlang.org/show_bug.cgi?id=19937

Mathias LANG <pro.mathias.lang@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Hardware|x86_64                      |All
                 OS|Linux                       |All
           Severity|enhancement                 |major

--
February 24
https://issues.dlang.org/show_bug.cgi?id=19937

--- Comment #5 from Mathias LANG <pro.mathias.lang@gmail.com> ---
@Seb: Thanks for the pointer. Unfortunately in the Vibe.d case it is nastier,
because the symbol takes a `ref` and a non-ref. Turns out `assert(x > y)` and
`assert(x > 0)` will generate different symbol (the former's second argument is
`ref` while the later is not, being a rvalue).

--
April 10
https://issues.dlang.org/show_bug.cgi?id=19937

Bastiaan Veelo <Bastiaan@Veelo.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |Bastiaan@Veelo.net

--- Comment #6 from Bastiaan Veelo <Bastiaan@Veelo.net> ---
Assuming Seb's assessment of phobos being compiled without `-checkaction=context` is the root cause, here is another test case:

```
import std;
void main()
{
  wchar[] c;
  c.toUTF8;
}
```

Compiling this with `-checkaction=context` produces
```
Error 42: Symbol Undefined
__D4core8internal7dassert__T24miniFormatFakeAttributesTkZQBdFNaNbNiNfKxkZAya
```

The link error vanishes if the argument `-debug` or `-release` is added, or if the import is changed into `import std.utf;`. This happens for DMD64 D Compiler v2.091.0-dirty on Windows, couldn't reproduce this on run.dlang.io.

Bastiaan.

--