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[ColdFire 55/63] Add support for vcall_offset thunks
This patch makes m68k_output_mi_thunk hnour vcall_offset. It was
easier to do this in rtl than by writing assembly directly, so the
patch converts the entire function to use rtl.
The main difficulty is in using a call-clobbered PIC register for the
duration of the thunk. I've used the same PIC_OFFSET_TABLE_REGNUM trick
that x86 and MIPS use.
Richard
gcc/
* config/m68k/m68k.h (PIC_OFFSET_TABLE_REGNUM): Use the REGNO
of pic_offset_table_rtx if reload_completed.
(CONDITIONAL_REGISTER_USAGE): Use PIC_REG instead of
PIC_OFFSET_TABLE_REGNUM.
* config/m68k/m68k.c (TARGET_ASM_CAN_OUTPUT_MI_THUNK): Always
return true.
(m68k_save_reg): Use PIC_REG instead of PIC_OFFSET_TABLE_REGNO.
(m68k_output_mi_thunk): Rewrite to use RTL. Honor vcall_offset.
Index: gcc/config/m68k/m68k.h
===================================================================
--- gcc/config/m68k/m68k.h 2007-01-09 16:12:15.000000000 +0000
+++ gcc/config/m68k/m68k.h 2007-01-09 16:12:15.000000000 +0000
@@ -316,7 +316,10 @@ #define MAX_LIBRARY_ID 255
#define FIRST_PSEUDO_REGISTER 25
/* All m68k targets (except AmigaOS) use %a5 as the PIC register */
-#define PIC_OFFSET_TABLE_REGNUM (flag_pic ? 13 : INVALID_REGNUM)
+#define PIC_OFFSET_TABLE_REGNUM \
+ (!flag_pic ? INVALID_REGNUM \
+ : reload_completed ? REGNO (pic_offset_table_rtx) \
+ : PIC_REG)
/* 1 for registers that have pervasive standard uses
and are not available for the register allocator.
@@ -383,9 +386,8 @@ #define CONDITIONAL_REGISTER_USAGE \
if (TEST_HARD_REG_BIT (x, i)) \
fixed_regs[i] = call_used_regs[i] = 1; \
} \
- if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM) \
- fixed_regs[PIC_OFFSET_TABLE_REGNUM] \
- = call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1; \
+ if (flag_pic) \
+ fixed_regs[PIC_REG] = call_used_regs[PIC_REG] = 1; \
}
/* On the m68k, ordinary registers hold 32 bits worth;
Index: gcc/config/m68k/m68k.c
===================================================================
--- gcc/config/m68k/m68k.c 2007-01-09 15:53:34.000000000 +0000
+++ gcc/config/m68k/m68k.c 2007-01-09 20:10:07.000000000 +0000
@@ -191,7 +191,7 @@ #define TARGET_ASM_UNALIGNED_SI_OP TARGE
#undef TARGET_ASM_OUTPUT_MI_THUNK
#define TARGET_ASM_OUTPUT_MI_THUNK m68k_output_mi_thunk
#undef TARGET_ASM_CAN_OUTPUT_MI_THUNK
-#define TARGET_ASM_CAN_OUTPUT_MI_THUNK default_can_output_mi_thunk_no_vcall
+#define TARGET_ASM_CAN_OUTPUT_MI_THUNK hook_bool_tree_hwi_hwi_tree_true
#undef TARGET_DEFAULT_TARGET_FLAGS
#define TARGET_DEFAULT_TARGET_FLAGS MASK_STRICT_ALIGNMENT
@@ -742,7 +742,7 @@ m68k_initial_elimination_offset (int fro
static bool
m68k_save_reg (unsigned int regno, bool interrupt_handler)
{
- if (flag_pic && regno == PIC_OFFSET_TABLE_REGNUM)
+ if (flag_pic && regno == PIC_REG)
{
/* We need to restore the PIC register on exceptional returns. */
if (current_function_calls_eh_return)
@@ -4050,59 +4050,93 @@ m68k_coff_asm_named_section (const char
static void
m68k_output_mi_thunk (FILE *file, tree thunk ATTRIBUTE_UNUSED,
- HOST_WIDE_INT delta,
- HOST_WIDE_INT vcall_offset ATTRIBUTE_UNUSED,
+ HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
tree function)
{
- rtx xops[1];
- const char *fmt;
+ rtx this_slot, offset, addr, mem, insn;
- if (delta > 0 && delta <= 8)
- asm_fprintf (file, (MOTOROLA
- ? "\taddq.l %I%d,4(%Rsp)\n"
- : "\taddql %I%d,%Rsp@(4)\n"),
- (int) delta);
- else if (delta < 0 && delta >= -8)
- asm_fprintf (file, (MOTOROLA
- ? "\tsubq.l %I%d,4(%Rsp)\n"
- : "\tsubql %I%d,%Rsp@(4)\n"),
- (int) -delta);
- else if (TARGET_COLDFIRE)
- {
- /* ColdFire can't add/sub a constant to memory unless it is in
- the range of addq/subq. So load the value into %d0 and
- then add it to 4(%sp). */
- if (delta >= -128 && delta <= 127)
- asm_fprintf (file, (MOTOROLA
- ? "\tmoveq.l %I%wd,%Rd0\n"
- : "\tmoveql %I%wd,%Rd0\n"),
- delta);
- else
- asm_fprintf (file, (MOTOROLA
- ? "\tmove.l %I%wd,%Rd0\n"
- : "\tmovel %I%wd,%Rd0\n"),
- delta);
- asm_fprintf (file, (MOTOROLA
- ? "\tadd.l %Rd0,4(%Rsp)\n"
- : "\taddl %Rd0,%Rsp@(4)\n"));
+ /* Pretend to be a post-reload pass while generating rtl. */
+ no_new_pseudos = 1;
+ reload_completed = 1;
+ reset_block_changes ();
+ allocate_reg_info (FIRST_PSEUDO_REGISTER, true, true);
+
+ /* The "this" pointer is stored at 4(%sp). */
+ this_slot = gen_rtx_MEM (Pmode, plus_constant (stack_pointer_rtx, 4));
+
+ /* Add DELTA to THIS. */
+ if (delta != 0)
+ {
+ /* Make the offset a legitimate operand for memory addition. */
+ offset = GEN_INT (delta);
+ if ((delta < -8 || delta > 8)
+ && (TARGET_COLDFIRE || USE_MOVQ (delta)))
+ {
+ emit_move_insn (gen_rtx_REG (Pmode, D0_REG), offset);
+ offset = gen_rtx_REG (Pmode, D0_REG);
+ }
+ emit_insn (gen_add3_insn (copy_rtx (this_slot),
+ copy_rtx (this_slot), offset));
}
- else
- asm_fprintf (file, (MOTOROLA
- ? "\tadd.l %I%wd,4(%Rsp)\n"
- : "\taddl %I%wd,%Rsp@(4)\n"),
- delta);
-
- xops[0] = DECL_RTL (function);
-
- gcc_assert (MEM_P (xops[0])
- && symbolic_operand (XEXP (xops[0], 0), VOIDmode));
- xops[0] = XEXP (xops[0], 0);
-
- fmt = m68k_symbolic_jump;
- if (m68k_symbolic_jump == NULL)
- fmt = "move.l %%a1@GOT(%%a5), %%a1\n\tjmp (%%a1)";
- output_asm_insn (fmt, xops);
+ /* If needed, add *(*THIS + VCALL_OFFSET) to THIS. */
+ if (vcall_offset != 0)
+ {
+ /* Set the static chain register to *THIS. */
+ emit_move_insn (static_chain_rtx, this_slot);
+ emit_move_insn (static_chain_rtx, gen_rtx_MEM (Pmode, static_chain_rtx));
+
+ /* Set ADDR to a legitimate address for *THIS + VCALL_OFFSET. */
+ addr = plus_constant (static_chain_rtx, vcall_offset);
+ if (!m68k_legitimate_address_p (Pmode, addr, true))
+ {
+ emit_insn (gen_rtx_SET (VOIDmode, static_chain_rtx, addr));
+ addr = static_chain_rtx;
+ }
+
+ /* Load the offset into %d0 and add it to THIS. */
+ emit_move_insn (gen_rtx_REG (Pmode, D0_REG),
+ gen_rtx_MEM (Pmode, addr));
+ emit_insn (gen_add3_insn (copy_rtx (this_slot),
+ copy_rtx (this_slot),
+ gen_rtx_REG (Pmode, D0_REG)));
+ }
+
+ /* Jump to the target function. Use a sibcall if direct jumps are
+ allowed, otherwise load the address into a register first. */
+ mem = DECL_RTL (function);
+ if (!sibcall_operand (XEXP (mem, 0), VOIDmode))
+ {
+ gcc_assert (flag_pic);
+
+ if (!TARGET_SEP_DATA)
+ {
+ /* Use the static chain register as a temporary (call-clobbered)
+ GOT pointer for this function. We can use the static chain
+ register because it isn't live on entry to the thunk. */
+ REGNO (pic_offset_table_rtx) = STATIC_CHAIN_REGNUM;
+ emit_insn (gen_load_got (pic_offset_table_rtx));
+ }
+ legitimize_pic_address (XEXP (mem, 0), Pmode, static_chain_rtx);
+ mem = replace_equiv_address (mem, static_chain_rtx);
+ }
+ insn = emit_call_insn (gen_sibcall (mem, const0_rtx));
+ SIBLING_CALL_P (insn) = 1;
+
+ /* Run just enough of rest_of_compilation. */
+ insn = get_insns ();
+ split_all_insns_noflow ();
+ final_start_function (insn, file, 1);
+ final (insn, file, 1);
+ final_end_function ();
+
+ /* Clean up the vars set above. */
+ reload_completed = 0;
+ no_new_pseudos = 0;
+
+ /* Restore the original PIC register. */
+ if (flag_pic)
+ REGNO (pic_offset_table_rtx) = PIC_REG;
}
/* Worker function for TARGET_STRUCT_VALUE_RTX. */