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xtensa: gcc: implement MI thunk generation for call0 ABI

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gcc/
	* config/xtensa/xtensa.cc (xtensa_can_output_mi_thunk)
	(xtensa_output_mi_thunk): New functions.
	(TARGET_ASM_CAN_OUTPUT_MI_THUNK)
	(TARGET_ASM_OUTPUT_MI_THUNK): New macro definitions.
	(xtensa_prepare_expand_call): Use fixed register a8 as temporary
	when called with reload_completed set to 1.
This commit is contained in:
Max Filippov 2022-07-14 02:39:59 -07:00
parent 4bdf739f83
commit 0bf60f68ed
1 changed files with 115 additions and 1 deletions
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116
gcc/config/xtensa/xtensa.cc
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@ -191,6 +191,15 @@ static bool xtensa_can_eliminate (const int from ATTRIBUTE_UNUSED,
static HOST_WIDE_INT xtensa_starting_frame_offset (void);
static unsigned HOST_WIDE_INT xtensa_asan_shadow_offset (void);
static bool xtensa_function_ok_for_sibcall (tree, tree);
static bool xtensa_can_output_mi_thunk (const_tree thunk_fndecl ATTRIBUTE_UNUSED,
HOST_WIDE_INT delta ATTRIBUTE_UNUSED,
HOST_WIDE_INT vcall_offset ATTRIBUTE_UNUSED,
const_tree function ATTRIBUTE_UNUSED);
static void xtensa_output_mi_thunk (FILE *file, tree thunk ATTRIBUTE_UNUSED,
HOST_WIDE_INT delta,
HOST_WIDE_INT vcall_offset,
tree function);
static rtx xtensa_delegitimize_address (rtx);
@ -351,6 +360,12 @@ static rtx xtensa_delegitimize_address (rtx);
#undef TARGET_FUNCTION_OK_FOR_SIBCALL
#define TARGET_FUNCTION_OK_FOR_SIBCALL xtensa_function_ok_for_sibcall
#undef TARGET_ASM_CAN_OUTPUT_MI_THUNK
#define TARGET_ASM_CAN_OUTPUT_MI_THUNK xtensa_can_output_mi_thunk
#undef TARGET_ASM_OUTPUT_MI_THUNK
#define TARGET_ASM_OUTPUT_MI_THUNK xtensa_output_mi_thunk
struct gcc_target targetm = TARGET_INITIALIZER;
@ -2173,7 +2188,16 @@ xtensa_prepare_expand_call (int callop, rtx *operands)
addr = gen_sym_PLT (addr);
if (!call_insn_operand (addr, VOIDmode))
XEXP (operands[callop], 0) = copy_to_mode_reg (Pmode, addr);
{
/* This may be called while generating MI thunk when we pretend
that reload is over. Use a8 as a temporary register in that case. */
rtx reg = can_create_pseudo_p ()
? copy_to_mode_reg (Pmode, addr)
: copy_to_suggested_reg (addr,
gen_rtx_REG (Pmode, A8_REG),
Pmode);
XEXP (operands[callop], 0) = reg;
}
}
@ -4983,6 +5007,96 @@ xtensa_function_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED, tree exp ATTRIBUTE_U
return true;
}
static bool
xtensa_can_output_mi_thunk (const_tree thunk_fndecl ATTRIBUTE_UNUSED,
HOST_WIDE_INT delta ATTRIBUTE_UNUSED,
HOST_WIDE_INT vcall_offset ATTRIBUTE_UNUSED,
const_tree function ATTRIBUTE_UNUSED)
{
if (TARGET_WINDOWED_ABI)
return false;
return true;
}
/* Output code to add DELTA to the first argument, and then jump
to FUNCTION. Used for C++ multiple inheritance. */
static void
xtensa_output_mi_thunk (FILE *file, tree thunk ATTRIBUTE_UNUSED,
HOST_WIDE_INT delta,
HOST_WIDE_INT vcall_offset,
tree function)
{
rtx this_rtx;
rtx funexp;
rtx_insn *insn;
int this_reg_no;
rtx temp0 = gen_rtx_REG (Pmode, A9_REG);
const char *fnname = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (thunk));
reload_completed = 1;
if (aggregate_value_p (TREE_TYPE (TREE_TYPE (function)), function))
this_reg_no = 3;
else
this_reg_no = 2;
this_rtx = gen_rtx_REG (Pmode, A0_REG + this_reg_no);
if (delta)
{
if (xtensa_simm8 (delta))
emit_insn (gen_addsi3 (this_rtx, this_rtx, GEN_INT (delta)));
else
{
emit_move_insn (temp0, GEN_INT (delta));
emit_insn (gen_addsi3 (this_rtx, this_rtx, temp0));
}
}
if (vcall_offset)
{
rtx temp1 = gen_rtx_REG (Pmode, A0_REG + 10);
rtx addr = temp1;
emit_move_insn (temp0, gen_rtx_MEM (Pmode, this_rtx));
if (xtensa_uimm8x4 (vcall_offset))
addr = plus_constant (Pmode, temp0, vcall_offset);
else if (xtensa_simm8 (vcall_offset))
emit_insn (gen_addsi3 (temp1, temp0, GEN_INT (vcall_offset)));
else
{
emit_move_insn (temp1, GEN_INT (vcall_offset));
emit_insn (gen_addsi3 (temp1, temp0, temp1));
}
emit_move_insn (temp1, gen_rtx_MEM (Pmode, addr));
emit_insn (gen_add2_insn (this_rtx, temp1));
}
/* Generate a tail call to the target function. */
if (!TREE_USED (function))
{
assemble_external (function);
TREE_USED (function) = 1;
}
funexp = XEXP (DECL_RTL (function), 0);
funexp = gen_rtx_MEM (FUNCTION_MODE, funexp);
insn = emit_call_insn (gen_sibcall (funexp, const0_rtx));
SIBLING_CALL_P (insn) = 1;
insn = get_insns ();
shorten_branches (insn);
assemble_start_function (thunk, fnname);
final_start_function (insn, file, 1);
final (insn, file, 1);
final_end_function ();
assemble_end_function (thunk, fnname);
/* Stop pretending to be a post-reload pass. */
reload_completed = 0;
}
static rtx
xtensa_delegitimize_address (rtx op)
{