Hi!
crtbegin.o is miscompiled on powerpc64-linux with -mminimal-toc (and likely
many other sources). The problem is that when flag_pic is 0, the
shrink-wrapping code doesn't consider register r30 being set up by the
prologue, so instructions that use r30 (TOC_REGISTER) can be considered
usable even without an earlier prologue that computes it.
Unfortunately the generic code adds just a couple of selected registers
to set_up_by_prologue regset, and I don't see without a target hook a way
to add further registers to the hard regset.
So, this patch implements such a hook and uses it on rs6000 to indicate that
r30 is computed by the prologue if the prologue does that.
Bootstrapped/regtested on powerpc64-linux (with -mminimal-toc in
CFLAGS/CXXFLAGS/etc., which previously failed to bootstrap) and on
x86_64-linux and i686-linux. Ok for trunk?
2012-01-17 Jakub Jelinek <ja...@redhat.com>
PR bootstrap/51872
* hard-reg-set.h (struct hard_reg_set_container): New type.
* target.h (struct hard_reg_set_container): Forward declare.
* target.def (set_up_by_prologue): New target hook.
* doc/tm.texi (TARGET_SET_UP_BY_PROLOGUE): Document it.
* function.c (thread_prologue_and_epilogue_insns): Change
set_up_by_prologue HARD_REG_SET into struct hard_reg_set_container.
Call targetm.set_up_by_prologue on it.
* config/rs6000/rs6000.c (rs6000_set_up_by_prologue): New function.
(TARGET_SET_UP_BY_PROLOGUE): Redefine to it.
--- gcc/hard-reg-set.h.jj 2011-11-28 17:58:04.000000000 +0100
+++ gcc/hard-reg-set.h 2012-01-16 17:27:35.837610779 +0100
@@ -54,6 +54,14 @@ typedef HARD_REG_ELT_TYPE HARD_REG_SET[H
#endif
+/* HARD_REG_SET wrapped into a structure, to make it possible to
+ use HARD_REG_SET even in APIs that should not include
+ hard-reg-set.h. */
+struct hard_reg_set_container
+{
+ HARD_REG_SET set;
+};
+
/* HARD_CONST is used to cast a constant to the appropriate type
for use with a HARD_REG_SET. */
--- gcc/target.h.jj 2011-06-17 11:02:19.000000000 +0200
+++ gcc/target.h 2012-01-16 17:28:13.348394331 +0100
@@ -92,6 +92,7 @@ extern bool target_default_pointer_addre
struct stdarg_info;
struct spec_info_def;
+struct hard_reg_set_container;
/* The struct used by the secondary_reload target hook. */
typedef struct secondary_reload_info
--- gcc/target.def.jj 2011-12-27 11:39:49.000000000 +0100
+++ gcc/target.def 2012-01-16 19:51:00.171464193 +0100
@@ -2644,6 +2644,14 @@ DEFHOOK
void, (bitmap regs),
hook_void_bitmap)
+/* Fill in additional registers set up by prologue into a regset. */
+DEFHOOK
+(set_up_by_prologue,
+ "This hook should add additional registers that are computed by the prologue\
+ to the hard regset for shrink-wrapping optimization purposes.",
+ void, (struct hard_reg_set_container *),
+ NULL)
+
/* Determine the type of unwind info to emit for debugging. */
DEFHOOK
(debug_unwind_info,
--- gcc/doc/tm.texi.jj 2011-12-27 11:39:47.000000000 +0100
+++ gcc/doc/tm.texi 2012-01-16 19:51:59.000000000 +0100
@@ -4959,6 +4959,10 @@ TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_R
FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_SET_UP_BY_PROLOGUE (struct
hard_reg_set_container *@var{})
+This hook should add additional registers that are computed by the prologue to
the hard regset for shrink-wrapping optimization purposes.
+@end deftypefn
+
@node Stack Smashing Protection
@subsection Stack smashing protection
@cindex stack smashing protection
--- gcc/doc/tm.texi.in.jj 2011-12-27 11:39:47.000000000 +0100
+++ gcc/doc/tm.texi.in 2012-01-16 19:51:38.531284609 +0100
@@ -4906,6 +4906,8 @@ TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_R
FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.
@end deftypefn
+@hook TARGET_SET_UP_BY_PROLOGUE
+
@node Stack Smashing Protection
@subsection Stack smashing protection
@cindex stack smashing protection
--- gcc/function.c.jj 2012-01-13 21:47:35.000000000 +0100
+++ gcc/function.c 2012-01-16 17:42:49.485331902 +0100
@@ -5899,7 +5899,7 @@ thread_prologue_and_epilogue_insns (void
&& nonempty_prologue && !crtl->calls_eh_return)
{
HARD_REG_SET prologue_clobbered, prologue_used, live_on_edge;
- HARD_REG_SET set_up_by_prologue;
+ struct hard_reg_set_container set_up_by_prologue;
rtx p_insn;
VEC(basic_block, heap) *vec;
basic_block bb;
@@ -5939,18 +5939,22 @@ thread_prologue_and_epilogue_insns (void
vec = VEC_alloc (basic_block, heap, n_basic_blocks);
- CLEAR_HARD_REG_SET (set_up_by_prologue);
- add_to_hard_reg_set (&set_up_by_prologue, Pmode, STACK_POINTER_REGNUM);
- add_to_hard_reg_set (&set_up_by_prologue, Pmode, ARG_POINTER_REGNUM);
+ CLEAR_HARD_REG_SET (set_up_by_prologue.set);
+ add_to_hard_reg_set (&set_up_by_prologue.set, Pmode,
+ STACK_POINTER_REGNUM);
+ add_to_hard_reg_set (&set_up_by_prologue.set, Pmode, ARG_POINTER_REGNUM);
if (frame_pointer_needed)
- add_to_hard_reg_set (&set_up_by_prologue, Pmode,
+ add_to_hard_reg_set (&set_up_by_prologue.set, Pmode,
HARD_FRAME_POINTER_REGNUM);
if (pic_offset_table_rtx)
- add_to_hard_reg_set (&set_up_by_prologue, Pmode,
+ add_to_hard_reg_set (&set_up_by_prologue.set, Pmode,
PIC_OFFSET_TABLE_REGNUM);
if (stack_realign_drap && crtl->drap_reg)
- add_to_hard_reg_set (&set_up_by_prologue, GET_MODE (crtl->drap_reg),
+ add_to_hard_reg_set (&set_up_by_prologue.set,
+ GET_MODE (crtl->drap_reg),
REGNO (crtl->drap_reg));
+ if (targetm.set_up_by_prologue)
+ targetm.set_up_by_prologue (&set_up_by_prologue);
/* We don't use a different max size depending on
optimize_bb_for_speed_p because increasing shrink-wrapping
@@ -5968,7 +5972,7 @@ thread_prologue_and_epilogue_insns (void
if (NONDEBUG_INSN_P (insn))
{
if (requires_stack_frame_p (insn, prologue_used,
- set_up_by_prologue))
+ set_up_by_prologue.set))
{
if (bb == entry_edge->dest)
goto fail_shrinkwrap;
--- gcc/config/rs6000/rs6000.c.jj 2012-01-13 21:47:35.000000000 +0100
+++ gcc/config/rs6000/rs6000.c 2012-01-16 18:01:04.615010096 +0100
@@ -1227,6 +1227,7 @@ static bool rs6000_cannot_force_const_me
static bool rs6000_legitimate_constant_p (enum machine_mode, rtx);
static bool rs6000_save_toc_in_prologue_p (void);
static void rs6000_code_end (void) ATTRIBUTE_UNUSED;
+static void rs6000_set_up_by_prologue (struct hard_reg_set_container *);
/* Hash table stuff for keeping track of TOC entries. */
@@ -1392,6 +1393,9 @@ static const struct attribute_spec rs600
#define TARGET_ASM_ASSEMBLE_VISIBILITY rs6000_assemble_visibility
#endif
+#undef TARGET_SET_UP_BY_PROLOGUE
+#define TARGET_SET_UP_BY_PROLOGUE rs6000_set_up_by_prologue
+
#undef TARGET_HAVE_TLS
#define TARGET_HAVE_TLS HAVE_AS_TLS
@@ -27903,6 +27907,19 @@ rs6000_code_end (void)
current_function_decl = NULL;
}
+/* Add r30 to hard reg set if the prologue sets it up and it is not
+ pic_offset_table_rtx. */
+
+static void
+rs6000_set_up_by_prologue (struct hard_reg_set_container *set)
+{
+ if (!TARGET_SINGLE_PIC_BASE
+ && TARGET_TOC
+ && TARGET_MINIMAL_TOC
+ && get_pool_size () != 0)
+ add_to_hard_reg_set (&set->set, Pmode, RS6000_PIC_OFFSET_TABLE_REGNUM);
+}
+
struct gcc_target targetm = TARGET_INITIALIZER;
#include "gt-rs6000.h"
Jakub
