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tcg: Add TCG_OPF_BB_EXIT

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Use this to notice the opcodes that exit the TB, which implies
that local temps are really dead and need not be synced.

Previously we so marked the true end of the TB, but that was
immediately overwritten by the la_bb_end invoked by any
TCG_OPF_BB_END opcode, like exit_tb.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2018-11-27 13:45:08 -08:00
parent f65a061c39
commit ae36a246ed
3 changed files with 16 additions and 10 deletions
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7
tcg/tcg-opc.h
View File

@ -191,9 +191,10 @@ DEF(mulsh_i64, 1, 2, 0, IMPL64 | IMPL(TCG_TARGET_HAS_mulsh_i64))
/* QEMU specific */
DEF(insn_start, 0, 0, TLADDR_ARGS * TARGET_INSN_START_WORDS,
TCG_OPF_NOT_PRESENT)
DEF(exit_tb, 0, 0, 1, TCG_OPF_BB_END)
DEF(goto_tb, 0, 0, 1, TCG_OPF_BB_END)
DEF(goto_ptr, 0, 1, 0, TCG_OPF_BB_END | IMPL(TCG_TARGET_HAS_goto_ptr))
DEF(exit_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
DEF(goto_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
DEF(goto_ptr, 0, 1, 0,
TCG_OPF_BB_EXIT | TCG_OPF_BB_END | IMPL(TCG_TARGET_HAS_goto_ptr))
DEF(qemu_ld_i32, 1, TLADDR_ARGS, 1,
TCG_OPF_CALL_CLOBBER | TCG_OPF_SIDE_EFFECTS)

5
tcg/tcg.c
View File

@ -2424,6 +2424,7 @@ static void liveness_pass_1(TCGContext *s)
int nb_temps = s->nb_temps;
TCGOp *op, *op_prev;
/* ??? Should be redundant with the exit_tb that ends the TB. */
la_func_end(s, nb_globals, nb_temps);
QTAILQ_FOREACH_REVERSE_SAFE(op, &s->ops, TCGOpHead, link, op_prev) {
@ -2612,7 +2613,9 @@ static void liveness_pass_1(TCGContext *s)
}
/* if end of basic block, update */
if (def->flags & TCG_OPF_BB_END) {
if (def->flags & TCG_OPF_BB_EXIT) {
la_func_end(s, nb_globals, nb_temps);
} else if (def->flags & TCG_OPF_BB_END) {
la_bb_end(s, nb_globals, nb_temps);
} else if (def->flags & TCG_OPF_SIDE_EFFECTS) {
la_global_sync(s, nb_globals);

14
tcg/tcg.h
View File

@ -1030,20 +1030,22 @@ typedef struct TCGArgConstraint {
/* Bits for TCGOpDef->flags, 8 bits available. */
enum {
/* Instruction exits the translation block. */
TCG_OPF_BB_EXIT = 0x01,
/* Instruction defines the end of a basic block. */
TCG_OPF_BB_END = 0x01,
TCG_OPF_BB_END = 0x02,
/* Instruction clobbers call registers and potentially update globals. */
TCG_OPF_CALL_CLOBBER = 0x02,
TCG_OPF_CALL_CLOBBER = 0x04,
/* Instruction has side effects: it cannot be removed if its outputs
are not used, and might trigger exceptions. */
TCG_OPF_SIDE_EFFECTS = 0x04,
TCG_OPF_SIDE_EFFECTS = 0x08,
/* Instruction operands are 64-bits (otherwise 32-bits). */
TCG_OPF_64BIT = 0x08,
TCG_OPF_64BIT = 0x10,
/* Instruction is optional and not implemented by the host, or insn
is generic and should not be implemened by the host. */
TCG_OPF_NOT_PRESENT = 0x10,
TCG_OPF_NOT_PRESENT = 0x20,
/* Instruction operands are vectors. */
TCG_OPF_VECTOR = 0x20,
TCG_OPF_VECTOR = 0x40,
};
typedef struct TCGOpDef {