[LLVMdev] gfortran: patch, question

Michael McCracken michael.mccracken at gmail.com
Fri Sep 1 12:43:48 PDT 2006

On 9/1/06, Chris Lattner <sabre at nondot.org> wrote:
> On Fri, 1 Sep 2006, Michael McCracken wrote:
> > I wanted to know if I should submit patches with comments around them
> > like the "APPLE LOCAL LLVM" ones that mark the LLVM-only changes to
> > the tree. I'd like to make it as easy as possible to apply these, so
> > let me know any rules I should be following.
> Don't worry about them.  The rules for use are finicky and they are easy
> to add.  I'll add them to any patches.  Thanks!

OK, thanks - I'll just keep my patches clean and let you worry about
the markers.


> This is crashing because make_decl_rtl is an RTL backend specific
> function.  I haven't looked at the callsite but you probably want
> something like this:
> #ifndef ENABLE_LLVM
>      make_decl_rtl (olddecl);
> #else
>      make_decl_llvm (olddecl);
> #endif
> make_decl_rtl is also sometimes called implicitly by "DECL_RTL".  Any uses
> of DECL_RTL need to be replaced with DECL_LLVM.  If you have questions on
> a particular use, I'd be happy to help.

OK, that makes sense. I should have been able to figure that out myself, huh :\
There are only a few cases of make_decl_rtl in the fortran code, so I
replaced them all as you suggested. It seemed straightforward in each

I've attached a patch for the changes to the make_decl_rtl callsites,
at the end.

Now f951 doesn't crash when compiling, but still can't compile the
libgfortran files. It now finds some syntax errors in a generated file
that's part of the intrinsics library.

It does compile a very simple test program. It generates
reasonable-looking LLVM code, except for using "MAIN__" instead of
"main" for the main procedure. I suspect that may be solved by
libgfortran once that's working. After editing that, the simple
example runs in lli up to the linking errors where the libgfortran
routines are called.

I'm looking into the errors, and I'll update the list on any progress.

Index: gcc/fortran/f95-lang.c
--- gcc/fortran/f95-lang.c      (revision 160)
+++ gcc/fortran/f95-lang.c      (working copy)
@@ -713,7 +713,11 @@
   TREE_PUBLIC (decl) = 1;
   if (library_name)
     SET_DECL_ASSEMBLER_NAME (decl, get_identifier (library_name));
+#ifndef ENABLE_LLVM
   make_decl_rtl (decl);
+  make_decl_llvm (decl);
   pushdecl (decl);
   DECL_BUILT_IN_CLASS (decl) = class;
   DECL_FUNCTION_CODE (decl) = function_code;
Index: gcc/fortran/trans-decl.c
--- gcc/fortran/trans-decl.c    (revision 160)
+++ gcc/fortran/trans-decl.c    (working copy)
@@ -1334,7 +1334,11 @@

   /* Create RTL for function definition.  */
+#ifndef ENABLE_LLVM
   make_decl_rtl (fndecl);
+  make_decl_llvm (fndecl);

   init_function_start (fndecl);

@@ -2472,8 +2476,11 @@
   current_function_decl = fndecl;

   rest_of_decl_compilation (fndecl, 1, 0);
+#ifndef ENABLE_LLVM
   make_decl_rtl (fndecl);
+  make_decl_llvm (fndecl);

   init_function_start (fndecl);


Michael McCracken
UCSD CSE PhD Candidate
research: http://www.cse.ucsd.edu/~mmccrack/
misc: http://michael-mccracken.net/wp/

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