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tcg/sparc: Add tcg_out_jmpl_const for better tail calls 

Due to mapping changes, we now rarely place the code_gen_buffer
near the main executable.  Which means that direct calls will
now rarely be in range.

So, always use indirect calls for tail calls, which allows us to
avoid clobbering %o7, and therefore we need not save and restore it.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-08-05 02:23:05 +03:00
parent c834b8d81b
commit e01d60f211
1 changed files with 23 additions and 14 deletions
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37
tcg/sparc/tcg-target.c.inc
View File

@ -858,6 +858,19 @@ static void tcg_out_addsub2_i64(TCGContext *s, TCGReg rl, TCGReg rh,
tcg_out_mov(s, TCG_TYPE_I64, rl, tmp);
}
static void tcg_out_jmpl_const(TCGContext *s, const tcg_insn_unit *dest,
bool in_prologue, bool tail_call)
{
uintptr_t desti = (uintptr_t)dest;
/* Be careful not to clobber %o7 for a tail call. */
tcg_out_movi_int(s, TCG_TYPE_PTR, TCG_REG_T1,
desti & ~0xfff, in_prologue,
tail_call ? TCG_REG_G2 : TCG_REG_O7);
tcg_out_arithi(s, tail_call ? TCG_REG_G0 : TCG_REG_O7,
TCG_REG_T1, desti & 0xfff, JMPL);
}
static void tcg_out_call_nodelay(TCGContext *s, const tcg_insn_unit *dest,
bool in_prologue)
{
@ -866,10 +879,7 @@ static void tcg_out_call_nodelay(TCGContext *s, const tcg_insn_unit *dest,
if (disp == (int32_t)disp) {
tcg_out32(s, CALL | (uint32_t)disp >> 2);
} else {
uintptr_t desti = (uintptr_t)dest;
tcg_out_movi_int(s, TCG_TYPE_PTR, TCG_REG_T1,
desti & ~0xfff, in_prologue, TCG_REG_O7);
tcg_out_arithi(s, TCG_REG_O7, TCG_REG_T1, desti & 0xfff, JMPL);
tcg_out_jmpl_const(s, dest, in_prologue, false);
}
}
@ -960,11 +970,10 @@ static void build_trampolines(TCGContext *s)
/* Set the retaddr operand. */
tcg_out_mov(s, TCG_TYPE_PTR, ra, TCG_REG_O7);
/* Set the env operand. */
tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O0, TCG_AREG0);
/* Tail call. */
tcg_out_call_nodelay(s, qemu_ld_helpers[i], true);
tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O7, ra);
tcg_out_jmpl_const(s, qemu_ld_helpers[i], true, true);
/* delay slot -- set the env argument */
tcg_out_mov_delay(s, TCG_REG_O0, TCG_AREG0);
}
for (i = 0; i < ARRAY_SIZE(qemu_st_helpers); ++i) {
@ -1006,14 +1015,14 @@ static void build_trampolines(TCGContext *s)
if (ra >= TCG_REG_O6) {
tcg_out_st(s, TCG_TYPE_PTR, TCG_REG_O7, TCG_REG_CALL_STACK,
TCG_TARGET_CALL_STACK_OFFSET);
ra = TCG_REG_G1;
}
} else {
tcg_out_mov(s, TCG_TYPE_PTR, ra, TCG_REG_O7);
/* Set the env operand. */
tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O0, TCG_AREG0);
}
/* Tail call. */
tcg_out_call_nodelay(s, qemu_st_helpers[i], true);
tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O7, ra);
tcg_out_jmpl_const(s, qemu_st_helpers[i], true, true);
/* delay slot -- set the env argument */
tcg_out_mov_delay(s, TCG_REG_O0, TCG_AREG0);
}
}
#endif