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[interp] Squash multiple call args moves into single opcode #52242

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Merged
BrzVlad merged 3 commits into from
May 14, 2021
Merged

[interp] Squash multiple call args moves into single opcode #52242

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c13831e
[interp] Replace multiplication and division by 1 with simple mov
BrzVlad Apr 30, 2021
b6d7053
[interp] Skip emitting redundant branch to next basic block
BrzVlad Apr 30, 2021
397c998
[interp] Squash multiple call args moves into single opcode
BrzVlad Apr 30, 2021
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[interp] Squash multiple call args moves into single opcode 
Some vars cannot be used directly as an argument to another call. In this case, the var offset allocator generates new intermediary vars. For methods with a lot of parameters, we can end up with quite a lot of these stores.

As an example, for the following method:
```
public static void MethodPartial (int a, int b, object c, object d)
{
	MethodFull (a, b, c, d, 12523);
}
```

Before:
```
IR_0000: ldc.i8         [72 <- nil], 12523
IR_0006: mov.4          [40 <- 0],
IR_0009: mov.4          [48 <- 8],
IR_000c: mov.8          [56 <- 16],
IR_000f: mov.8          [64 <- 24],
IR_0012: call           [32 <- 40], 0
IR_0016: ret.void       [nil <- nil],
```

After:
```
IR_0000: ldc.i8         [72 <- nil], 12523
IR_0006: mov.8.4        [nil <- nil], 40 <- 0, 48 <- 8, 56 <- 16, 64 <- 24
IR_000f: call           [32 <- 40], 0
IR_0013: ret.void       [nil <- nil]
```
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@BrzVlad
BrzVlad committed May 4, 2021
commit 397c998039f1570135de6ba145f12cc7d98a631e
19 changes: 19 additions & 0 deletions src/mono/mono/mini/interp/interp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6576,6 +6576,25 @@ MINT_IN_CASE(MINT_BRTRUE_I8_SP) ZEROP_SP(gint64, !=); MINT_IN_BREAK;
MINT_IN_BREAK;
}

MINT_IN_CASE(MINT_MOV_8_2)
LOCAL_VAR (ip [1], guint64) = LOCAL_VAR (ip [2], guint64);
LOCAL_VAR (ip [3], guint64) = LOCAL_VAR (ip [4], guint64);
ip += 5;
MINT_IN_BREAK;
MINT_IN_CASE(MINT_MOV_8_3)
LOCAL_VAR (ip [1], guint64) = LOCAL_VAR (ip [2], guint64);
LOCAL_VAR (ip [3], guint64) = LOCAL_VAR (ip [4], guint64);
LOCAL_VAR (ip [5], guint64) = LOCAL_VAR (ip [6], guint64);
ip += 7;
MINT_IN_BREAK;
MINT_IN_CASE(MINT_MOV_8_4)
LOCAL_VAR (ip [1], guint64) = LOCAL_VAR (ip [2], guint64);
LOCAL_VAR (ip [3], guint64) = LOCAL_VAR (ip [4], guint64);
LOCAL_VAR (ip [5], guint64) = LOCAL_VAR (ip [6], guint64);
LOCAL_VAR (ip [7], guint64) = LOCAL_VAR (ip [8], guint64);
ip += 9;
MINT_IN_BREAK;

MINT_IN_CASE(MINT_LOCALLOC) {
int len = LOCAL_VAR (ip [2], gint32);
gpointer mem = frame_data_allocator_alloc (&context->data_stack, frame, ALIGN_TO (len, MINT_VT_ALIGNMENT));
Expand Down
6 changes: 6 additions & 0 deletions src/mono/mono/mini/interp/mintops.def
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Expand Up @@ -108,6 +108,12 @@ OPDEF(MINT_MOV_4, "mov.4", 3, 1, 1, MintOpNoArgs)
OPDEF(MINT_MOV_8, "mov.8", 3, 1, 1, MintOpNoArgs)
OPDEF(MINT_MOV_VT, "mov.vt", 4, 1, 1, MintOpShortInt)

// These opcodes represent multiple moves stacked together. They have multiple src and dst
// but they are not represented here. They are generated by the var offset allocator.
OPDEF(MINT_MOV_8_2, "mov.8.2", 5, 0, 0, MintOpPair2)
OPDEF(MINT_MOV_8_3, "mov.8.3", 7, 0, 0, MintOpPair3)
OPDEF(MINT_MOV_8_4, "mov.8.4", 9, 0, 0, MintOpPair4)

OPDEF(MINT_LDLOCA_S, "ldloca.s", 3, 1, 0, MintOpUShortInt)

OPDEF(MINT_LDIND_I1, "ldind.i1", 3, 1, 1, MintOpNoArgs)
Expand Down
7 changes: 6 additions & 1 deletion src/mono/mono/mini/interp/mintops.h
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Expand Up @@ -24,7 +24,10 @@ typedef enum
MintOpClassToken,
MintOpTwoShorts,
MintOpShortAndInt,
MintOpShortAndShortBranch
MintOpShortAndShortBranch,
MintOpPair2,
MintOpPair3,
MintOpPair4
} MintOpArgType;

#define OPDEF(a,b,c,d,e,f) a,
Expand Down Expand Up @@ -74,6 +77,8 @@ typedef enum {
#define MINT_CALL_ARGS 2
#define MINT_CALL_ARGS_SREG -2

#define MINT_MOV_PAIRS_MAX 4

extern unsigned char const mono_interp_oplen[];
extern int const mono_interp_op_dregs [];
extern int const mono_interp_op_sregs [];
Expand Down
74 changes: 63 additions & 11 deletions src/mono/mono/mini/interp/transform.c
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Expand Up @@ -1411,6 +1411,14 @@ dump_interp_ins_data (InterpInst *ins, gint32 ins_offset, const guint16 *data, g
target = ins_offset + *(gint16*)(data + 1);
g_string_append_printf (str, " %u, IR_%04x", *(guint16*)data, target);
}
case MintOpPair2:
g_string_append_printf (str, " %u <- %u, %u <- %u", data [0], data [1], data [2], data [3]);
break;
case MintOpPair3:
g_string_append_printf (str, " %u <- %u, %u <- %u, %u <- %u", data [0], data [1], data [2], data [3], data [4], data [5]);
break;
case MintOpPair4:
g_string_append_printf (str, " %u <- %u, %u <- %u, %u <- %u, %u <- %u", data [0], data [1], data [2], data [3], data [4], data [5], data [6], data [7]);
break;
default:
g_string_append_printf (str, "unknown arg type\n");
Expand Down Expand Up @@ -7650,6 +7658,12 @@ emit_compacted_instruction (TransformData *td, guint16* start_ip, InterpInst *in
for (int i = size - 1; i < (jit_call2_size - 1); i++)
*ip++ = MINT_NIY;
#endif
} else if (opcode >= MINT_MOV_8_2 && opcode <= MINT_MOV_8_4) {
// This instruction is not marked as operating on any vars, all instruction slots are
// actually vas. Resolve their offset
int num_vars = mono_interp_oplen [opcode] - 1;
for (int i = 0; i < num_vars; i++)
*ip++ = td->locals [ins->data [i]].offset;
} else {
if (mono_interp_op_dregs [opcode])
*ip++ = td->locals [ins->dreg].offset;
Expand Down Expand Up @@ -9146,7 +9160,11 @@ interp_alloc_offsets (TransformData *td)
if (ins->flags & INTERP_INST_FLAG_CALL) {
int *call_args = ins->info.call_args;
if (call_args) {
int pair_sregs [MINT_MOV_PAIRS_MAX];
int pair_dregs [MINT_MOV_PAIRS_MAX];
int num_pairs = 0;
int var = *call_args;

while (var != -1) {
if (td->locals [var].flags & INTERP_LOCAL_FLAG_GLOBAL ||
td->locals [var].flags & INTERP_LOCAL_FLAG_NO_CALL_ARGS) {
Expand All @@ -9155,17 +9173,27 @@ interp_alloc_offsets (TransformData *td)
int new_var = create_interp_local (td, td->locals [var].type);
td->locals [new_var].call = ins;
td->locals [new_var].flags |= INTERP_LOCAL_FLAG_CALL_ARGS;
int opcode = get_mov_for_type (mint_type (td->locals [var].type), FALSE);
InterpInst *new_inst = interp_insert_ins_bb (td, bb, ins->prev, opcode);
interp_ins_set_dreg (new_inst, new_var);
interp_ins_set_sreg (new_inst, var);
if (opcode == MINT_MOV_VT)
new_inst->data [0] = td->locals [var].size;
// The arg of the call is no longer global
*call_args = new_var;
// Also update liveness for this instruction
foreach_local_var (td, new_inst, ins_index, set_var_live_range);
ins_index++;

int mt = mint_type (td->locals [var].type);
if (mt != MINT_TYPE_VT && num_pairs < MINT_MOV_PAIRS_MAX) {
pair_sregs [num_pairs] = var;
pair_dregs [num_pairs] = new_var;
num_pairs++;
// The arg of the call is no longer global
*call_args = new_var;
} else {
int opcode = get_mov_for_type (mt, FALSE);
InterpInst *new_inst = interp_insert_ins_bb (td, bb, ins->prev, opcode);
interp_ins_set_dreg (new_inst, new_var);
interp_ins_set_sreg (new_inst, var);
if (opcode == MINT_MOV_VT)
new_inst->data [0] = td->locals [var].size;
// The arg of the call is no longer global
*call_args = new_var;
// Also update liveness for this instruction
foreach_local_var (td, new_inst, ins_index, set_var_live_range);
ins_index++;
}
} else {
// Flag this var as it has special storage on the call args stack
td->locals [var].call = ins;
Expand All @@ -9174,6 +9202,30 @@ interp_alloc_offsets (TransformData *td)
call_args++;
var = *call_args;
}
if (num_pairs > 0) {
int i;
for (i = 0; i < num_pairs; i++) {
set_var_live_range (td, pair_sregs [i], ins_index);
set_var_live_range (td, pair_dregs [i], ins_index);
}
if (num_pairs == 1) {
int mt = mint_type (td->locals [pair_sregs [0]].type);
int opcode = get_mov_for_type (mt, FALSE);
InterpInst *new_inst = interp_insert_ins_bb (td, bb, ins->prev, opcode);
interp_ins_set_dreg (new_inst, pair_dregs [0]);
interp_ins_set_sreg (new_inst, pair_sregs [0]);
} else {
// Squash together multiple moves to the param area into a single opcode
int opcode = MINT_MOV_8_2 + num_pairs - 2;
InterpInst *new_inst = interp_insert_ins_bb (td, bb, ins->prev, opcode);
int k = 0;
for (i = 0; i < num_pairs; i++) {
new_inst->data [k++] = pair_dregs [i];
new_inst->data [k++] = pair_sregs [i];
}
}
ins_index++;
}
}
}
// Set live_start and live_end for every referenced local that is not global
Expand Down