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author | Richard Henderson <richard.henderson@linaro.org> | 2022-10-31 09:22:59 +1100 |
---|---|---|
committer | Richard Henderson <richard.henderson@linaro.org> | 2023-02-04 06:19:42 -1000 |
commit | 313bdea84d2912fdbb139e746bd9346b3d85ebdc (patch) | |
tree | ece6023111f149e77828df532aa11a1fd688428e /tcg | |
parent | 6a6d772e30d62e209587ef341df243e9789f5a9f (diff) | |
download | qemu-313bdea84d2912fdbb139e746bd9346b3d85ebdc.zip qemu-313bdea84d2912fdbb139e746bd9346b3d85ebdc.tar.gz qemu-313bdea84d2912fdbb139e746bd9346b3d85ebdc.tar.bz2 |
tcg: Add TCG_CALL_{RET,ARG}_BY_REF
These will be used by some hosts, both 32 and 64-bit, to pass and
return i128. Not yet used, because allocation is not yet enabled.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'tcg')
-rw-r--r-- | tcg/tcg-internal.h | 3 | ||||
-rw-r--r-- | tcg/tcg.c | 135 |
2 files changed, 135 insertions, 3 deletions
diff --git a/tcg/tcg-internal.h b/tcg/tcg-internal.h index 6e50aeb..2ec1ea0 100644 --- a/tcg/tcg-internal.h +++ b/tcg/tcg-internal.h @@ -36,6 +36,7 @@ */ typedef enum { TCG_CALL_RET_NORMAL, /* by registers */ + TCG_CALL_RET_BY_REF, /* for i128, by reference */ } TCGCallReturnKind; typedef enum { @@ -44,6 +45,8 @@ typedef enum { TCG_CALL_ARG_EXTEND, /* for i32, as a sign/zero-extended i64 */ TCG_CALL_ARG_EXTEND_U, /* ... as a zero-extended i64 */ TCG_CALL_ARG_EXTEND_S, /* ... as a sign-extended i64 */ + TCG_CALL_ARG_BY_REF, /* for i128, by reference, first */ + TCG_CALL_ARG_BY_REF_N, /* ... by reference, subsequent */ } TCGCallArgumentKind; typedef struct TCGCallArgumentLoc { @@ -104,8 +104,7 @@ static void tcg_out_ld(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg1, static bool tcg_out_mov(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg); static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg ret, tcg_target_long arg); -static void tcg_out_addi_ptr(TCGContext *s, TCGReg, TCGReg, tcg_target_long) - __attribute__((unused)); +static void tcg_out_addi_ptr(TCGContext *s, TCGReg, TCGReg, tcg_target_long); static void tcg_out_exit_tb(TCGContext *s, uintptr_t arg); static void tcg_out_goto_tb(TCGContext *s, int which); static void tcg_out_op(TCGContext *s, TCGOpcode opc, @@ -683,6 +682,38 @@ static void layout_arg_normal_n(TCGCumulativeArgs *cum, cum->arg_slot += n; } +static void layout_arg_by_ref(TCGCumulativeArgs *cum, TCGHelperInfo *info) +{ + TCGCallArgumentLoc *loc = &info->in[cum->info_in_idx]; + int n = 128 / TCG_TARGET_REG_BITS; + + /* The first subindex carries the pointer. */ + layout_arg_1(cum, info, TCG_CALL_ARG_BY_REF); + + /* + * The callee is allowed to clobber memory associated with + * structure pass by-reference. Therefore we must make copies. + * Allocate space from "ref_slot", which will be adjusted to + * follow the parameters on the stack. + */ + loc[0].ref_slot = cum->ref_slot; + + /* + * Subsequent words also go into the reference slot, but + * do not accumulate into the regular arguments. + */ + for (int i = 1; i < n; ++i) { + loc[i] = (TCGCallArgumentLoc){ + .kind = TCG_CALL_ARG_BY_REF_N, + .arg_idx = cum->arg_idx, + .tmp_subindex = i, + .ref_slot = cum->ref_slot + i, + }; + } + cum->info_in_idx += n; + cum->ref_slot += n; +} + static void init_call_layout(TCGHelperInfo *info) { int max_reg_slots = ARRAY_SIZE(tcg_target_call_iarg_regs); @@ -718,6 +749,14 @@ static void init_call_layout(TCGHelperInfo *info) case TCG_CALL_RET_NORMAL: assert(info->nr_out <= ARRAY_SIZE(tcg_target_call_oarg_regs)); break; + case TCG_CALL_RET_BY_REF: + /* + * Allocate the first argument to the output. + * We don't need to store this anywhere, just make it + * unavailable for use in the input loop below. + */ + cum.arg_slot = 1; + break; default: qemu_build_not_reached(); } @@ -796,6 +835,9 @@ static void init_call_layout(TCGHelperInfo *info) case TCG_CALL_ARG_NORMAL: layout_arg_normal_n(&cum, info, 128 / TCG_TARGET_REG_BITS); break; + case TCG_CALL_ARG_BY_REF: + layout_arg_by_ref(&cum, info); + break; default: qemu_build_not_reached(); } @@ -811,7 +853,39 @@ static void init_call_layout(TCGHelperInfo *info) assert(cum.info_in_idx <= ARRAY_SIZE(info->in)); /* Validate the backend has enough argument space. */ assert(cum.arg_slot <= max_reg_slots + max_stk_slots); - assert(cum.ref_slot <= max_stk_slots); + + /* + * Relocate the "ref_slot" area to the end of the parameters. + * Minimizing this stack offset helps code size for x86, + * which has a signed 8-bit offset encoding. + */ + if (cum.ref_slot != 0) { + int ref_base = 0; + + if (cum.arg_slot > max_reg_slots) { + int align = __alignof(Int128) / sizeof(tcg_target_long); + + ref_base = cum.arg_slot - max_reg_slots; + if (align > 1) { + ref_base = ROUND_UP(ref_base, align); + } + } + assert(ref_base + cum.ref_slot <= max_stk_slots); + + if (ref_base != 0) { + for (int i = cum.info_in_idx - 1; i >= 0; --i) { + TCGCallArgumentLoc *loc = &info->in[i]; + switch (loc->kind) { + case TCG_CALL_ARG_BY_REF: + case TCG_CALL_ARG_BY_REF_N: + loc->ref_slot += ref_base; + break; + default: + break; + } + } + } + } } static int indirect_reg_alloc_order[ARRAY_SIZE(tcg_target_reg_alloc_order)]; @@ -1740,6 +1814,8 @@ void tcg_gen_callN(void *func, TCGTemp *ret, int nargs, TCGTemp **args) switch (loc->kind) { case TCG_CALL_ARG_NORMAL: + case TCG_CALL_ARG_BY_REF: + case TCG_CALL_ARG_BY_REF_N: op->args[pi++] = temp_arg(ts); break; @@ -4411,6 +4487,27 @@ static void load_arg_normal(TCGContext *s, const TCGCallArgumentLoc *l, } } +static void load_arg_ref(TCGContext *s, int arg_slot, TCGReg ref_base, + intptr_t ref_off, TCGRegSet *allocated_regs) +{ + TCGReg reg; + int stk_slot = arg_slot - ARRAY_SIZE(tcg_target_call_iarg_regs); + + if (stk_slot < 0) { + reg = tcg_target_call_iarg_regs[arg_slot]; + tcg_reg_free(s, reg, *allocated_regs); + tcg_out_addi_ptr(s, reg, ref_base, ref_off); + tcg_regset_set_reg(*allocated_regs, reg); + } else { + reg = tcg_reg_alloc(s, tcg_target_available_regs[TCG_TYPE_PTR], + *allocated_regs, 0, false); + tcg_out_addi_ptr(s, reg, ref_base, ref_off); + tcg_out_st(s, TCG_TYPE_PTR, reg, TCG_REG_CALL_STACK, + TCG_TARGET_CALL_STACK_OFFSET + + stk_slot * sizeof(tcg_target_long)); + } +} + static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op) { const int nb_oargs = TCGOP_CALLO(op); @@ -4434,6 +4531,16 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op) case TCG_CALL_ARG_EXTEND_S: load_arg_normal(s, loc, ts, &allocated_regs); break; + case TCG_CALL_ARG_BY_REF: + load_arg_stk(s, loc->ref_slot, ts, allocated_regs); + load_arg_ref(s, loc->arg_slot, TCG_REG_CALL_STACK, + TCG_TARGET_CALL_STACK_OFFSET + + loc->ref_slot * sizeof(tcg_target_long), + &allocated_regs); + break; + case TCG_CALL_ARG_BY_REF_N: + load_arg_stk(s, loc->ref_slot, ts, allocated_regs); + break; default: g_assert_not_reached(); } @@ -4465,6 +4572,19 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op) save_globals(s, allocated_regs); } + /* + * If the ABI passes a pointer to the returned struct as the first + * argument, load that now. Pass a pointer to the output home slot. + */ + if (info->out_kind == TCG_CALL_RET_BY_REF) { + TCGTemp *ts = arg_temp(op->args[0]); + + if (!ts->mem_allocated) { + temp_allocate_frame(s, ts); + } + load_arg_ref(s, 0, ts->mem_base->reg, ts->mem_offset, &allocated_regs); + } + tcg_out_call(s, tcg_call_func(op), info); /* Assign output registers and emit moves if needed. */ @@ -4481,6 +4601,15 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op) ts->mem_coherent = 0; } break; + + case TCG_CALL_RET_BY_REF: + /* The callee has performed a write through the reference. */ + for (i = 0; i < nb_oargs; i++) { + TCGTemp *ts = arg_temp(op->args[i]); + ts->val_type = TEMP_VAL_MEM; + } + break; + default: g_assert_not_reached(); } |