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tcg: Split out tcg_out_goto_tb

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The INDEX_op_goto_tb opcode needs no register allocation.
Split out a dedicated helper function for it.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-11-26 17:14:05 -08:00
parent becc452a36
commit cf7d6b8e98
11 changed files with 199 additions and 173 deletions
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49
tcg/arm/tcg-target.c.inc
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@ -1939,6 +1939,31 @@ static void tcg_out_exit_tb(TCGContext *s, uintptr_t arg)
tcg_out_epilogue(s);
}
static void tcg_out_goto_tb(TCGContext *s, int which)
{
/* Indirect jump method */
intptr_t ptr, dif, dil;
TCGReg base = TCG_REG_PC;
qemu_build_assert(!TCG_TARGET_HAS_direct_jump);
ptr = get_jmp_target_addr(s, which);
dif = tcg_pcrel_diff(s, (void *)ptr) - 8;
dil = sextract32(dif, 0, 12);
if (dif != dil) {
/*
* The TB is close, but outside the 12 bits addressable by
* the load. We can extend this to 20 bits with a sub of a
* shifted immediate from pc. In the vastly unlikely event
* the code requires more than 1MB, we'll use 2 insns and
* be no worse off.
*/
base = TCG_REG_R0;
tcg_out_movi32(s, COND_AL, base, ptr - dil);
}
tcg_out_ld32_12(s, COND_AL, TCG_REG_PC, base, dil);
set_jmp_reset_offset(s, which);
}
static void tcg_out_op(TCGContext *s, TCGOpcode opc,
const TCGArg args[TCG_MAX_OP_ARGS],
const int const_args[TCG_MAX_OP_ARGS])
@ -1947,29 +1972,6 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
int c;
switch (opc) {
case INDEX_op_goto_tb:
{
/* Indirect jump method */
intptr_t ptr, dif, dil;
TCGReg base = TCG_REG_PC;
qemu_build_assert(!TCG_TARGET_HAS_direct_jump);
ptr = get_jmp_target_addr(s, args[0]);
dif = tcg_pcrel_diff(s, (void *)ptr) - 8;
dil = sextract32(dif, 0, 12);
if (dif != dil) {
/* The TB is close, but outside the 12 bits addressable by
the load. We can extend this to 20 bits with a sub of a
shifted immediate from pc. In the vastly unlikely event
the code requires more than 1MB, we'll use 2 insns and
be no worse off. */
base = TCG_REG_R0;
tcg_out_movi32(s, COND_AL, base, ptr - dil);
}
tcg_out_ld32_12(s, COND_AL, TCG_REG_PC, base, dil);
set_jmp_reset_offset(s, args[0]);
}
break;
case INDEX_op_goto_ptr:
tcg_out_b_reg(s, COND_AL, args[0]);
break;
@ -2259,6 +2261,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
case INDEX_op_mov_i32: /* Always emitted via tcg_out_mov. */
case INDEX_op_call: /* Always emitted via tcg_out_call. */
case INDEX_op_exit_tb: /* Always emitted via tcg_out_exit_tb. */
case INDEX_op_goto_tb: /* Always emitted via tcg_out_goto_tb. */
default:
tcg_abort();
}