[LLVMbugs] [Bug 14299] New: Incorrect codegen for static local with address of local label in constructor

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=14299

             Bug #: 14299
           Summary: Incorrect codegen for static local with address of
                    local label in constructor
           Product: clang
           Version: trunk
          Platform: Macintosh
        OS/Version: MacOS X
            Status: NEW
          Severity: normal
          Priority: P
         Component: LLVM Codegen
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: a.bataev at gmx.com
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


clang generates incorrect code for the following code:

struct VirtualBase {
  VirtualBase() {}
};

struct Mike : virtual VirtualBase {
  Mike();
};

Mike::Mike() {
    static void *ouch =&&x;
    goto *ouch;
     x:;
}

struct Dave : virtual Mike {
  Dave() {}
};

int main()
{
  Mike *m = new Mike();
  VirtualBase *v = new Dave;
  Mike *m2 = new Mike();
  return 0;
}

clang++ -S -emit-llvm -o - test.cpp

Some excerpts from the generated code:
...
@_ZZN4MikeC1EvE4ouch = internal global i8* blockaddress(@_ZN4MikeC2Ev, %x),
align 8
...
define void @_ZN4MikeC1Ev(%struct.Mike* %this) unnamed_addr uwtable ssp align 2
{
...

  %2 = load i8** @_ZZN4MikeC1EvE4ouch, align 8
  br label %indirectgoto

x:                                                ; preds = %indirectgoto
  ret void

indirectgoto:                                     ; preds = %entry
  %indirect.goto.dest = phi i8* [ %2, %entry ]
  indirectbr i8* %indirect.goto.dest, [label %x]
}
...
define void @_ZN4MikeC2Ev(%struct.Mike* %this, i8** %vtt) unnamed_addr nounwind
uwtable ssp align 2 {
...

  %2 = load i8** @_ZZN4MikeC1EvE4ouch, align 8
  br label %indirectgoto

x:                                                ; preds = %indirectgoto
  ret void

indirectgoto:                                     ; preds = %entry
  %indirect.goto.dest = phi i8* [ %2, %entry ]
  indirectbr i8* %indirect.goto.dest, [label %x]
}

There is a branch to the code in @_ZN4MikeC2Ev from @_ZN4MikeC1Ev happens.

Building an executable and running the test
clang++ test.cpp
./a.out
Bus error: 10

Alexey Bataev
Software Engineer
Intel Compiler Team
Intel Corp.

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