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digitalmars.D.bugs - [Issue 21120] New: Inconsistent mangling of __init symbol


          Issue ID: 21120
           Summary: Inconsistent mangling of __init symbol
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: johanengelen weka.io

File three.d:
module one.two.three;

StructTemplate!B instatiation;

struct B

struct StructTemplate(Opts)
    void foo()

template someTemplate(T) {
    pragma(msg, "_D" ~ T.mangleof[1..$] ~ "6__initZ");
    pragma(mangle, "_D" ~ T.mangleof[1..$] ~ "6__initZ")
    extern immutable typeof(T.init) initializer;

    void someTemplate()
        auto ptr = &initializer;

 dmd -of=/tmp/wrongmangle.o -c three.d
output: _D3one3two5three__T14StructTemplateTSQBjQBiQBh1BZQBe6__initZ
 nm /tmp/wrongmangle.o | grep ".*StructTemplate.*__initZ"
outputs: 0000000000000270 S __D3one3two5three__T14StructTemplateTS3oneQBjQBi1BZQBf6__initZ U __D3one3two5three__T14StructTemplateTSQBjQBiQBh1BZQBe6__initZ 00000000000001b8 S __D60TypeInfo_S3one3two5three__T14StructTemplateTSQBjQBiQBh1BZQBe6__initZ As you can see there is an undefined symbol: the one that we defined using pragma(mangle). The mangling is just slightly off to what the compiler defines. Note that the defined symbol `__D3one3two5three__T14StructTemplateTS3oneQBjQBi1BZQBf6__initZ` contains "one" twice. Somehow, the repeated identifier detection/encoding does not work. It _does_ work for the TypeInfo symbol (and all other symbols related to `StructTemplate!B`. This inconsistency between `T.mangleof` and the init symbol mangling is a blocker for implementing a druntime hack to access the init symbol similar to this article: http://dpldocs.info/this-week-in-d/Blog.Posted_2020_07_27.html#zero-runtime-classes --
Aug 05 2020