The current code generation for -mflat uses 3 insn patterns
which emit up two three insns (sort of) emulating the save
instruction.
The problem is that the unwind info is only produced at the
end of any pattern, leaving a 1 or 2 insn hole for which the
unwind info is not correct.
I tried to figure out why things had been done in this
slightly convoluted manner and failed. It seems to me that
this is easily represented with the individual instructions.
A comment indicated that there had been problems with the
copy to %o7 being deleted. Elsewhere we have successfully
used a naked USE pattern to keep such things from being
deleted.
Unfortunately, I can't seem to get -mflat to bootstrap on
gcc62 (as sparc-linux, not sparc64) either before or after
this patch, so I'm not sure what sort of pre-requisite I'm
missing in order to be able to test it...
Comments?
r~
commit 7c9f3f4fa56b6603007d254afad18c47009bc5af
Author: Richard Henderson <r...@twiddle.net>
Date: Mon Jun 20 16:42:14 2011 -0700
sparc: Fix -mflat unwind info.
The old definition left a 2 instruction hole in which
unwind info was out-of-date.
diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c
index e50d2f1..7d83dd6 100644
--- a/gcc/config/sparc/sparc.c
+++ b/gcc/config/sparc/sparc.c
@@ -4617,39 +4617,6 @@ emit_save_register_window (rtx increment)
return insn;
}
-/* Generate a create_flat_frame_1 insn. */
-
-static rtx
-gen_create_flat_frame_1 (rtx increment)
-{
- if (TARGET_ARCH64)
- return gen_create_flat_frame_1di (increment);
- else
- return gen_create_flat_frame_1si (increment);
-}
-
-/* Generate a create_flat_frame_2 insn. */
-
-static rtx
-gen_create_flat_frame_2 (rtx increment)
-{
- if (TARGET_ARCH64)
- return gen_create_flat_frame_2di (increment);
- else
- return gen_create_flat_frame_2si (increment);
-}
-
-/* Generate a create_flat_frame_3 insn. */
-
-static rtx
-gen_create_flat_frame_3 (rtx increment)
-{
- if (TARGET_ARCH64)
- return gen_create_flat_frame_3di (increment);
- else
- return gen_create_flat_frame_3si (increment);
-}
-
/* Generate an increment for the stack pointer. */
static rtx
@@ -4793,7 +4760,6 @@ sparc_flat_expand_prologue (void)
{
HOST_WIDE_INT size;
rtx insn;
- int i;
sparc_leaf_function_p = optimize > 0 && current_function_is_leaf;
@@ -4811,103 +4777,64 @@ sparc_flat_expand_prologue (void)
if (size == 0)
; /* do nothing. */
- else if (frame_pointer_needed)
+ else
{
- if (size <= 4096)
- {
- if (return_addr_reg_needed_p (sparc_leaf_function_p))
- insn = emit_insn (gen_create_flat_frame_1 (GEN_INT (-size)));
- else
- insn = emit_insn (gen_create_flat_frame_2 (GEN_INT (-size)));
- RTX_FRAME_RELATED_P (insn) = 1;
- for (i=0; i < XVECLEN (PATTERN (insn), 0); i++)
- RTX_FRAME_RELATED_P (XVECEXP (PATTERN (insn), 0, i)) = 1;
- }
- else
- {
- rtx reg = gen_rtx_REG (Pmode, 1), note;
- emit_move_insn (reg, GEN_INT (-size));
- if (return_addr_reg_needed_p (sparc_leaf_function_p))
- {
- insn = emit_insn (gen_create_flat_frame_1 (reg));
- note
- = gen_rtx_PARALLEL (VOIDmode,
- gen_rtvec
- (3, copy_rtx
- (XVECEXP (PATTERN (insn), 0, 0)),
- gen_stack_pointer_inc
- (GEN_INT (-size)),
- copy_rtx
- (XVECEXP (PATTERN (insn), 0, 2))));
- }
- else
- {
- insn = emit_insn (gen_create_flat_frame_2 (reg));
- note
- = gen_rtx_PARALLEL (VOIDmode,
- gen_rtvec
- (2, copy_rtx
- (XVECEXP (PATTERN (insn), 0, 0)),
- gen_stack_pointer_inc
- (GEN_INT (-size))));
- }
+ rtx size_int_rtx, size_rtx;
+
+ size_rtx = size_int_rtx = GEN_INT (-size);
- RTX_FRAME_RELATED_P (insn) = 1;
- add_reg_note (insn, REG_FRAME_RELATED_EXPR, note);
- for (i=0; i < XVECLEN (note, 0); i++)
- RTX_FRAME_RELATED_P (XVECEXP (note, 0, i)) = 1;
- }
- }
- else if (return_addr_reg_needed_p (sparc_leaf_function_p))
- {
if (size <= 4096)
+ insn = emit_insn (gen_stack_pointer_inc (size_int_rtx));
+ else if (size <= 8192 && !frame_pointer_needed)
{
- insn = emit_insn (gen_create_flat_frame_3 (GEN_INT (-size)));
+ insn = emit_insn (gen_stack_pointer_inc (GEN_INT (-4096)));
RTX_FRAME_RELATED_P (insn) = 1;
- for (i=0; i < XVECLEN (PATTERN (insn), 0); i++)
- RTX_FRAME_RELATED_P (XVECEXP (PATTERN (insn), 0, i)) = 1;
+ insn = emit_insn (gen_stack_pointer_inc (GEN_INT (4096 - size)));
}
else
{
- rtx reg = gen_rtx_REG (Pmode, 1), note;
- emit_move_insn (reg, GEN_INT (-size));
- insn = emit_insn (gen_create_flat_frame_3 (reg));
- note
- = gen_rtx_PARALLEL (VOIDmode,
- gen_rtvec
- (2, gen_stack_pointer_inc (GEN_INT (-size)),
- copy_rtx
- (XVECEXP (PATTERN (insn), 0, 1))));
- RTX_FRAME_RELATED_P (insn) = 1;
- add_reg_note (insn, REG_FRAME_RELATED_EXPR, note);
- for (i=0; i < XVECLEN (note, 0); i++)
- RTX_FRAME_RELATED_P (XVECEXP (note, 0, i)) = 1;
+ size_rtx = gen_rtx_REG (Pmode, 1);
+ emit_move_insn (size_rtx, size_int_rtx);
+ insn = emit_insn (gen_stack_pointer_inc (size_rtx));
+ add_reg_note (insn, REG_CFA_ADJUST_CFA,
+ gen_stack_pointer_inc (size_int_rtx));
}
- }
- else
- {
- if (size <= 4096)
- insn = emit_insn (gen_stack_pointer_inc (GEN_INT (-size)));
- else if (size <= 8192)
+ RTX_FRAME_RELATED_P (insn) = 1;
+
+ if (frame_pointer_needed)
{
- insn = emit_insn (gen_stack_pointer_inc (GEN_INT (-4096)));
+ insn = emit_insn (gen_rtx_SET (VOIDmode, hard_frame_pointer_rtx,
+ gen_rtx_MINUS (Pmode,
+ stack_pointer_rtx,
+ size_rtx)));
RTX_FRAME_RELATED_P (insn) = 1;
- insn = emit_insn (gen_stack_pointer_inc (GEN_INT (4096 - size)));
+
+ add_reg_note (insn, REG_CFA_ADJUST_CFA,
+ gen_rtx_SET (VOIDmode, hard_frame_pointer_rtx,
+ plus_constant (stack_pointer_rtx,
+ size)));
+
+ /* Make sure nothing is scheduled until after the frame
+ is established. */
+ emit_insn (gen_blockage ());
}
- else
+
+ if (return_addr_reg_needed_p (sparc_leaf_function_p))
{
- rtx reg = gen_rtx_REG (Pmode, 1);
- emit_move_insn (reg, GEN_INT (-size));
- insn = emit_insn (gen_stack_pointer_inc (reg));
- add_reg_note (insn, REG_FRAME_RELATED_EXPR,
- gen_stack_pointer_inc (GEN_INT (-size)));
- }
+ rtx i7 = gen_rtx_REG (Pmode, INCOMING_RETURN_ADDR_REGNUM);
+ rtx o7 = gen_rtx_REG (Pmode, RETURN_ADDR_REGNUM);
- RTX_FRAME_RELATED_P (insn) = 1;
- }
+ insn = emit_move_insn (o7, i7);
+ RTX_FRAME_RELATED_P (insn) = 1;
- /* Make sure nothing is scheduled until after the frame is established. */
- emit_insn (gen_blockage ());
+ add_reg_note (insn, REG_CFA_REGISTER,
+ gen_rtx_SET (VOIDmode, o7, i7));
+
+ /* Prevent this instruction from ever being considered dead,
+ even if this function has no epilogue. */
+ emit_insn (gen_rtx_USE (VOIDmode, o7));
+ }
+ }
if (frame_pointer_needed)
{
diff --git a/gcc/config/sparc/sparc.md b/gcc/config/sparc/sparc.md
index 017b689..2c8d306 100644
--- a/gcc/config/sparc/sparc.md
+++ b/gcc/config/sparc/sparc.md
@@ -6287,39 +6287,6 @@
"save\t%%sp, %0, %%sp"
[(set_attr "type" "savew")])
-;; For the "create flat frame" insns, we need to use special insns
-;; because %fp cannot be clobbered until after the frame is established (so
-;; that it contains the live register window save area) and %i7 changed with
-;; a simple move as it is a fixed register and the move would be eliminated.
-
-(define_insn "create_flat_frame_1<P:mode>"
- [(set (reg:P 30) (reg:P 14))
- (set (reg:P 14) (plus:P (reg:P 14)
- (match_operand:P 0 "arith_operand" "rI")))
- (set (reg:P 31) (reg:P 15))]
- "TARGET_FLAT"
- "add\t%%sp, %0, %%sp\n\tsub\t%%sp, %0, %%fp\n\tmov\t%%o7, %%i7"
- [(set_attr "type" "multi")
- (set_attr "length" "3")])
-
-(define_insn "create_flat_frame_2<P:mode>"
- [(set (reg:P 30) (reg:P 14))
- (set (reg:P 14) (plus:P (reg:P 14)
- (match_operand:P 0 "arith_operand" "rI")))]
- "TARGET_FLAT"
- "add\t%%sp, %0, %%sp\n\tsub\t%%sp, %0, %%fp"
- [(set_attr "type" "multi")
- (set_attr "length" "2")])
-
-(define_insn "create_flat_frame_3<P:mode>"
- [(set (reg:P 14) (plus:P (reg:P 14)
- (match_operand:P 0 "arith_operand" "rI")))
- (set (reg:P 31) (reg:P 15))]
- "TARGET_FLAT"
- "add\t%%sp, %0, %%sp\n\tmov\t%%o7, %%i7"
- [(set_attr "type" "multi")
- (set_attr "length" "2")])
-
(define_expand "epilogue"
[(return)]
""
