&& REGNO (frame_reg_rtx) != cr_save_regno
&& !(using_static_chain_p && cr_save_regno == 11))
{
- rtx set;
-
cr_save_rtx = gen_rtx_REG (SImode, cr_save_regno);
START_USE (cr_save_regno);
- insn = emit_insn (gen_movesi_from_cr (cr_save_rtx));
- RTX_FRAME_RELATED_P (insn) = 1;
- /* Now, there's no way that dwarf2out_frame_debug_expr is going
- to understand '(unspec:SI [(reg:CC 68) ...] UNSPEC_MOVESI_FROM_CR)'.
- But that's OK. All we have to do is specify that _one_ condition
- code register is saved in this stack slot. The thrower's epilogue
- will then restore all the call-saved registers.
- We use CR2_REGNO (70) to be compatible with gcc-2.95 on Linux. */
- set = gen_rtx_SET (VOIDmode, cr_save_rtx,
- gen_rtx_REG (SImode, CR2_REGNO));
- add_reg_note (insn, REG_FRAME_RELATED_EXPR, set);
+ emit_insn (gen_movesi_from_cr (cr_save_rtx));
}
/* Do any required saving of fpr's. If only one or two to save, do
rtx addr = gen_rtx_PLUS (Pmode, frame_reg_rtx,
GEN_INT (info->cr_save_offset + frame_off));
rtx mem = gen_frame_mem (SImode, addr);
- /* See the large comment above about why CR2_REGNO is used. */
- rtx magic_eh_cr_reg = gen_rtx_REG (SImode, CR2_REGNO);
/* If we didn't copy cr before, do so now using r0. */
if (cr_save_rtx == NULL_RTX)
{
- rtx set;
-
START_USE (0);
cr_save_rtx = gen_rtx_REG (SImode, 0);
- insn = emit_insn (gen_movesi_from_cr (cr_save_rtx));
- RTX_FRAME_RELATED_P (insn) = 1;
- set = gen_rtx_SET (VOIDmode, cr_save_rtx, magic_eh_cr_reg);
- add_reg_note (insn, REG_FRAME_RELATED_EXPR, set);
- }
- insn = emit_move_insn (mem, cr_save_rtx);
+ emit_insn (gen_movesi_from_cr (cr_save_rtx));
+ }
+
+ /* Saving CR requires a two-instruction sequence: one instruction
+ to move the CR to a general-purpose register, and a second
+ instruction that stores the GPR to memory.
+
+ We do not emit any DWARF CFI records for the first of these,
+ because we cannot properly represent the fact that CR is saved in
+ a register. One reason is that we cannot express that multiple
+ CR fields are saved; another reason is that on 64-bit, the size
+ of the CR register in DWARF (4 bytes) differs from the size of
+ a general-purpose register.
+
+ This means if any intervening instruction were to clobber one of
+ the call-saved CR fields, we'd have incorrect CFI. To prevent
+ this from happening, we mark the store to memory as a use of
+ those CR fields, which prevents any such instruction from being
+ scheduled in between the two instructions. */
+ rtx crsave_v[9];
+ int n_crsave = 0;
+ int i;
+
+ crsave_v[n_crsave++] = gen_rtx_SET (VOIDmode, mem, cr_save_rtx);
+ for (i = 0; i < 8; i++)
+ if (save_reg_p (CR0_REGNO + i))
+ crsave_v[n_crsave++]
+ = gen_rtx_USE (VOIDmode, gen_rtx_REG (CCmode, CR0_REGNO + i));
+
+ insn = emit_insn (gen_rtx_PARALLEL (VOIDmode,
+ gen_rtvec_v (n_crsave, crsave_v)));
END_USE (REGNO (cr_save_rtx));
- rs6000_frame_related (insn, frame_reg_rtx, sp_off - frame_off,
- NULL_RTX, NULL_RTX);
+ /* Now, there's no way that dwarf2out_frame_debug_expr is going to
+ understand '(unspec:SI [(reg:CC 68) ...] UNSPEC_MOVESI_FROM_CR)',
+ so we need to construct a frame expression manually. */
+ RTX_FRAME_RELATED_P (insn) = 1;
+
+ /* Update address to be stack-pointer relative, like
+ rs6000_frame_related would do. */
+ addr = gen_rtx_PLUS (Pmode, gen_rtx_REG (Pmode, STACK_POINTER_REGNUM),
+ GEN_INT (info->cr_save_offset + sp_off));
+ mem = gen_frame_mem (SImode, addr);
+
+ /* We still cannot express that multiple CR fields are saved in the
+ CR save slot. By convention, we use a single CR regnum to represent
+ the fact that all call-saved CR fields are saved. We use CR2_REGNO
+ to be compatible with gcc-2.95 on Linux. */
+ rtx set = gen_rtx_SET (VOIDmode, mem, gen_rtx_REG (SImode, CR2_REGNO));
+ add_reg_note (insn, REG_FRAME_RELATED_EXPR, set);
}
/* Update stack and set back pointer unless this is V.4,
projects / thirdparty / gcc.git / commitdiff
