[LLVMbugs] [Bug 3897] New: Can't execute *.bc with lli on Cygwin

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=3897

           Summary: Can't execute *.bc with lli on Cygwin
           Product: libraries
           Version: 2.5
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Backend: X86
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: vmi at nifty.com
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=2767)
 --> (http://llvm.org/bugs/attachment.cgi?id=2767)
llvm-2.5 patch for cygwin

There are two problems.

1> lli test/ExecutionEngine/hello.bc 

ERROR: Program used external function 'puts' which could not be resolved!
Aborted

The following problem occurs when the above problem is solved:

2> lli test/ExecutionEngine/hello.bc

assertion "Inserted && "Pass registered multiple times!"" failed: file
"Pass.cpp", line 149


1st problem:

- dlopen(0, ...) is not correctly executed.

----------------------------------------------------------------------
#include <stdio.h>
#include <dlfcn.h>
int main(void) {
  void *d;
  int (*f1)(const char *);
  int (*f2)(const char *);
  d = dlopen(0, RTLD_LAZY|RTLD_GLOBAL);
  f1 = dlsym(d, "puts");
  f2 = dlsym(0, "puts");
  printf("dlopen = %p\nputs(1) = %p\nputs(2) = %p\n", d, f1, f2);
  if (f1 != 0) f1("Run puts(1).");
  if (f2 != 0) f2("Run puts(2).");
  return 0;
}
----------------------------------------------------------------------

  * Linux (Debian Lenny x64)
    dlopen = 0x7f4d2b17c000
    puts(1) = 0x7f4d2aa711c0
    puts(2) = 0x7f4d2aa711c0
    Run puts(1).
    Run puts(2).

  * Cygwin on Windows XP:
    dlopen = 0x400000
    puts(1) = 0x0
    puts(2) = 0x610969b4
    Run puts(2).

  I patched to lib/System/DynamicLibrary.cpp. (see attached file)


2nd problem:

If run on Cygwin (or MinGW?), the following code is executed:

[lib/Target/X86/X86ISelDAGToDAG.cpp]
----------------------------------------------------------------------
/// EmitSpecialCodeForMain - Emit any code that needs to be executed only in
/// the main function.
void X86DAGToDAGISel::EmitSpecialCodeForMain(MachineBasicBlock *BB,
                                             MachineFrameInfo *MFI) {
  const TargetInstrInfo *TII = TM.getInstrInfo();
  if (Subtarget->isTargetCygMing())
    BuildMI(BB, DebugLoc::getUnknownLoc(),
            TII->get(X86::CALLpcrel32)).addExternalSymbol("__main");
}
----------------------------------------------------------------------

However, this brings the following results when execute *.bc with lli:

1) Before executing main of lli, execute __main -> do_do_global_ctors ->
constructors of global variables -> ... -> RegisterPass at lib/VMCore/Pass.cpp

2) When executting main of *.bc, re-execute __main -> do_do_global_ctors ->
constructors of global variables -> ... -> RegisterPass at lib/VMCore/Pass.cpp ->
assert!!

I think that I should not execute __main.

I patched to lib/Target/X86/X86ISelDAGToDAG.cpp. (see attached file)


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