1 /*
2 * Copyright 2023 Alyssa Rosenzweig
3 * SPDX-License-Identifier: MIT
4 */
5
6 #include "util/macros.h"
7 #include "agx_builder.h"
8 #include "agx_compile.h"
9 #include "agx_compiler.h"
10
11 /* Lower moves involving memory registers (created when spilling) to concrete
12 * spills and fills.
13 */
14
15 static void
spill_fill(agx_builder * b,agx_instr * I,enum agx_size size,unsigned channels,unsigned component_offset_el)16 spill_fill(agx_builder *b, agx_instr *I, enum agx_size size, unsigned channels,
17 unsigned component_offset_el)
18 {
19 unsigned size_B = agx_size_align_16(size) * 2;
20 enum agx_format format = size_B == 2 ? AGX_FORMAT_I16 : AGX_FORMAT_I32;
21 unsigned format_size_B = size_B == 2 ? 2 : 4;
22
23 unsigned offset_B = component_offset_el * size_B;
24 unsigned effective_chans = size == AGX_SIZE_64 ? (channels * 2) : channels;
25 unsigned mask = BITFIELD_MASK(effective_chans);
26
27 assert(effective_chans <= 4);
28
29 /* Pick off the memory and register parts of the move */
30 agx_index mem = I->dest[0].memory ? I->dest[0] : I->src[0];
31 agx_index reg = I->dest[0].memory ? I->src[0] : I->dest[0];
32
33 assert(mem.type == AGX_INDEX_REGISTER && mem.memory);
34 assert(reg.type == AGX_INDEX_REGISTER && !reg.memory);
35
36 /* Slice the register according to the part of the spill we're handling */
37 if (component_offset_el > 0 || channels != agx_channels(reg)) {
38 reg.value += component_offset_el * agx_size_align_16(reg.size);
39 reg.channels_m1 = channels - 1;
40 }
41
42 /* Calculate stack offset in bytes. IR registers are 2-bytes each. */
43 unsigned stack_offs_B = b->shader->spill_base_B + (mem.value * 2) + offset_B;
44 unsigned stack_offs_end_B = stack_offs_B + (effective_chans * format_size_B);
45
46 assert(stack_offs_end_B <= b->shader->scratch_size_B &&
47 "RA allocates enough scratch");
48
49 /* Emit the spill/fill */
50 if (I->dest[0].memory) {
51 agx_stack_store(b, reg, agx_immediate(stack_offs_B), format, mask);
52 } else {
53 agx_stack_load_to(b, reg, agx_immediate(stack_offs_B), format, mask);
54 }
55 }
56
57 void
agx_lower_spill(agx_context * ctx)58 agx_lower_spill(agx_context *ctx)
59 {
60 agx_foreach_instr_global_safe(ctx, I) {
61 if (I->op != AGX_OPCODE_MOV || (!I->dest[0].memory && !I->src[0].memory))
62 continue;
63
64 enum agx_size size = I->dest[0].size;
65 unsigned channels = agx_channels(I->dest[0]);
66
67 assert(size == I->src[0].size);
68 assert(channels == agx_channels(I->src[0]));
69
70 /* Texture gradient sources can be vec6, and if such a vector is spilled,
71 * we need to be able to spill/fill a vec6. Since stack_store/stack_load
72 * only work up to vec4, we break up into (at most) vec4 components.
73 */
74 agx_builder b = agx_init_builder(ctx, agx_before_instr(I));
75
76 for (unsigned c = 0; c < channels; c += 4) {
77 spill_fill(&b, I, size, MIN2(channels - c, 4), c);
78 }
79
80 agx_remove_instruction(I);
81 }
82 }
83