Bug 19548 – [REG 2.080] Missing reference to _D6object__T14__switch_errorZQrFNaNbNiNfAyamZv

Since 2.080 the following code, compiled in debug mode, doesn't link anymore: import std.stdio, std.bitmanip; void main() { int i; final switch (i) { case 0: {} } writef(""); } The output from the linker (bfd or gold) is: function _Dmain: error: undefined reference to '_D6object__T14__switch_errorZQrFNaNbNiNfAyamZv' Compiling the same program with -allinst, -release or -O works.

Reduced a bit further import std.stdio, std.bitmanip; void main() { final switch (0) { } writef(""); }

The linker error is different for me if I add -debug to the mix when compiling :D --- foo.o:foo.d:_D76TypeInfo_S3std3uni__T13InversionListTSQBcQBb8GcPolicyZQBh__T9IntervalsTAkZQo6__initZ: error: undefined reference to '_D6object__T10RTInfoImplVAmA2i32i8Z4datayG2m' foo.o:foo.d:_D48TypeInfo_S3std3uni__T8CowArrayTSQwQu8GcPolicyZQz6__initZ: error: undefined reference to '_D6object__T10RTInfoImplVAmA2i16i2Z4datayG2m' --- Also as the behavior is different for `-checkaction=C`, I presume it runs into this: https://github.com/dlang/dmd/blob/92408ea7b43f9636a5e5b0426d7c6ffd73576ca2/src/dmd/statementsem.d#L2596 Specifically CallExp needs to be a DotTemplateInstanceExp. So this should be a good start: --- diff --git a/src/dmd/statementsem.d b/src/dmd/statementsem.d index cd7ac9aca..3cb3f01c4 100644 --- a/src/dmd/statementsem.d +++ b/src/dmd/statementsem.d @@ -2602,16 +2602,16 @@ else } else { - Expression sl = new IdentifierExp(ss.loc, Id.empty); - sl = new DotIdExp(ss.loc, sl, Id.object); - sl = new DotIdExp(ss.loc, sl, Id.__switch_error); + Expression objectId = new IdentifierExp(ss.loc, Id.object); Expressions* args = new Expressions(); args.push(new StringExp(ss.loc, cast(char*) ss.loc.filename)); args.push(new IntegerExp(ss.loc.linnum)); - sl = new CallExp(ss.loc, sl, args); - sl.expressionSemantic(sc); + auto tiargs = new Objects(); + auto dt = new DotTemplateInstanceExp(ss.loc, objectId, Id.__switch_error, tiargs); + Expression sl = new CallExp(ss.loc, dt, args); + sl = sl.expressionSemantic(sc); s = new SwitchErrorStatement(ss.loc, sl); } --- However, it still doesn't trigger the instantiation.

PR: https://github.com/dlang/dmd/pull/9211

(In reply to Seb from comment #3) > PR: https://github.com/dlang/dmd/pull/9211 Please ignore this PR. While I think it's on a good track, it still doesn't fix the instantiation problem and the test wasn't testing the linking.

Shouldn't this be marked as critical or something? You hit this issue quite randomly depending on which part of std you use. Can you mark something as a regression AND critical?

I triggered this bug today some code. Works in -release mode for DMD and LDC2 only. GDC is fine. The created object files for DMD and LDC2 do NOT directly link against the symbol '_D6object__T14__switch_errorZQrFNaNbNiNfAyamZv'. So the missing symbol must be referenced by some of the libraries linked against the object.

I triggered this bug today some code. Works in -release mode for DMD and LDC2 only. GDC is fine. The created object files for DMD and LDC2 do NOT directly link against the symbol '_D6object__T14__switch_errorZQrFNaNbNiNfAyamZv'. So the missing symbol must be referenced by some of the libraries linked against the object.

I cannot reproduce this. The filed code snippet compiles successfully for both -release and -debug. Closing as WORKSFORME. Please reopen if the issue is not fixed.