[LLVMbugs] [Bug 9644] New: Adding dummy argument to Fortran external routines call breaks interop with other languages

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=9644

           Summary: Adding dummy argument to Fortran external routines
                    call breaks interop with other languages
           Product: new-bugs
           Version: trunk
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: maemarcus at gmail.com
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=6407)
 --> (http://llvm.org/bugs/attachment.cgi?id=6407)
test case source code

There is an openmpi configure test that writes a Fortran program sending two
sequential pointers of logical type to external function in C. The test is
expected to compute the size of type by difference between two addresses. But
instead of 2 args Fortran part sends 3, starting with 0.

Please see a test case in attachment.

1) Compile:

[dmikushin at tesla-cmc szlogical]$ make
./cgen-gfortran -g -c main.f90
./cgen-gcc -g -c size.c
dragonegg-gfortran main.o size.o -o szlogical

Note cgen-* scripts are implementing the compilation pipeline, looping the llvm
C backend: Source -> emit IR -> llc -> gcc

2) Run debugger:

[dmikushin at tesla-cmc szlogical]$ gdb ./szlogical 

(gdb) b size_
Breakpoint 1 at 0x400724: file size.c.bc.c, line 167.
(gdb) r
Starting program:
/home/dmikushin/Programming/kernelgen/tests/public/szlogical/szlogical 

Breakpoint 1, size_ (llvm_cbe_a=0x0, llvm_cbe_b=0x7fffffffdf50 "x\v`") at
size.c.bc.c:167
167      llvm_cbe_alloca_20_point = ((unsigned int )0u);
Missing separate debuginfos, use: debuginfo-install glibc-2.13-1.x86_64
libgcc-4.5.1-4.fc14.x86_64 libgfortran-4.5.1-4.fc14.x86_64
(gdb) f 0
#0  size_ (llvm_cbe_a=0x0, llvm_cbe_b=0x7fffffffdf50 "x\v`") at size.c.bc.c:167
167      llvm_cbe_alloca_20_point = ((unsigned int )0u);
(gdb) list
162      unsigned char *llvm_cbe_tmp__1;
163      unsigned char *llvm_cbe_tmp__2;
164      unsigned int llvm_cbe_ssa_20_point;
165      unsigned int llvm_cbe_tmp__3;
166    
167      llvm_cbe_alloca_20_point = ((unsigned int )0u);
168      *(&llvm_cbe_a_addr) = llvm_cbe_a;
169      *(&llvm_cbe_b_addr) = llvm_cbe_b;
170      llvm_cbe_tmp__1 = *(&llvm_cbe_b_addr);
171      llvm_cbe_tmp__2 = *(&llvm_cbe_a_addr);
(gdb) f 1
#1  0x0000000000400689 in MAIN__ (vararg_dummy_arg=0) at main.f90.bc.c:172
172      size_(0 /*dummy arg*/, ((&(*(((unsigned int *)(&llvm_cbe_memtmp)))))),
((&(((unsigned int *)(&llvm_cbe_memtmp)))[((signed long long )1ull)])));
(gdb) list
167      unsigned int llvm_cbe_alloca_20_point;
168      unsigned int llvm_cbe_ssa_20_point;
169    
170      llvm_cbe_alloca_20_point = ((unsigned int )0u);
171      llvm_cbe_ssa_20_point = ((unsigned int )0u);
172      size_(0 /*dummy arg*/, ((&(*(((unsigned int *)(&llvm_cbe_memtmp)))))),
((&(((unsigned int *)(&llvm_cbe_memtmp)))[((signed long long )1ull)])));
173      return;
174    }

3) The unexpected result: size_ function is called with 3 arguments, while it
actually accepts only 2, and everything gets corrupted.

4) Even simpler single language test has the same problem:

program fsize
external size
logical x(2)
call size(x(1),x(2))
end

subroutine size(X,Y)
end

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