On Jun 26, 2010, at 12:24 PM, Richard Sandiford wrote:
> GCC has a fair number of global variables that cache target-dependent
> data. This makes it difficult to switch between subtargets on the fly,
> such as when switching between a MIPS16 and a non-MIPS16 function.
>
> Our current approach is to call target_reinit each time we make such
> a switch. This function goes off and redoes a fair chunk of the target
> initialisation process, and although it works (or least worked) pretty well,
> it is very slow.
>
> * doc/tm.texi (SWITCHABLE_TARGET): Document.
> * Makefile.in (target_globals_def): New variable.
> (target_globals_h): Likewise.
> (TARGET_GLOBALS_H): Likewise.
> (OBJS-common): Add target-globals.o.
> (gtype-desc.o): Depend on $(TARGET_GLOBALS_H).
> (target-globals.o): New rule.
> ($(target_globals_h)): Likewise.
> (s-target-globals): Likewise.
> (GTFILES): Add $(target_globals_h).
> (build/gentarget-globals.o): New rule.
> * defaults.h (SWITCHABLE_TARGET): Define.
> * gengtype.c (open_base_files): Add target-globals.h to the
> include list.
> * target-globals.def: New file.
> * gentarget-globals.c: Likewise.
> * target-globals.c: Likewise.
First, thanks for the work. I have a switchable port, I seem to be seeing:
../../gcc/gcc/target-globals.c: In function ‘target_globals*
save_target_globals()’:
../../gcc/gcc/target-globals.c:69:33: error: ‘ggc_alloc_target_globals’ was not
declared in this scope
make: *** [target-globals.o] Error 1
after the switch to C++. I was wondering if your switchable target port
compiles post the switch to C++? Before the switch, I saw a C warning for
using ggc_alloc_target_globals undeclared.
With:
diff --git a/gcc/target-globals.c b/gcc/target-globals.c
index e679f21..4e33359 100644
--- a/gcc/target-globals.c
+++ b/gcc/target-globals.c
@@ -65,6 +65,7 @@ struct target_globals *
save_target_globals (void)
{
struct target_globals *g;
+ extern struct target_globals *ggc_alloc_target_globals (void);
g = ggc_alloc_target_globals ();
g->flag_state = XCNEW (struct target_flag_state);
my port again compiles. Certainly I hate block scoped external function
declarations, it is wrong... could you decide where it goes and drop in that
line someplace? Thanks.
