mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-11-30 23:10:05 +00:00
f0ca96d12c
When we determine the liveness of an insert, we have to ignore the debug instruction (it must not have any impact on the decision).
265 lines
10 KiB
C++
265 lines
10 KiB
C++
// Copyright (c) 2018 The Khronos Group Inc.
|
|
// Copyright (c) 2018 Valve Corporation
|
|
// Copyright (c) 2018 LunarG Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
#include "source/opt/dead_insert_elim_pass.h"
|
|
|
|
#include "source/opt/composite.h"
|
|
#include "source/opt/ir_context.h"
|
|
#include "source/opt/iterator.h"
|
|
#include "spirv/1.2/GLSL.std.450.h"
|
|
|
|
namespace spvtools {
|
|
namespace opt {
|
|
|
|
namespace {
|
|
|
|
const uint32_t kTypeVectorCountInIdx = 1;
|
|
const uint32_t kTypeMatrixCountInIdx = 1;
|
|
const uint32_t kTypeArrayLengthIdInIdx = 1;
|
|
const uint32_t kTypeIntWidthInIdx = 0;
|
|
const uint32_t kConstantValueInIdx = 0;
|
|
const uint32_t kInsertObjectIdInIdx = 0;
|
|
const uint32_t kInsertCompositeIdInIdx = 1;
|
|
|
|
} // anonymous namespace
|
|
|
|
uint32_t DeadInsertElimPass::NumComponents(Instruction* typeInst) {
|
|
switch (typeInst->opcode()) {
|
|
case SpvOpTypeVector: {
|
|
return typeInst->GetSingleWordInOperand(kTypeVectorCountInIdx);
|
|
} break;
|
|
case SpvOpTypeMatrix: {
|
|
return typeInst->GetSingleWordInOperand(kTypeMatrixCountInIdx);
|
|
} break;
|
|
case SpvOpTypeArray: {
|
|
uint32_t lenId =
|
|
typeInst->GetSingleWordInOperand(kTypeArrayLengthIdInIdx);
|
|
Instruction* lenInst = get_def_use_mgr()->GetDef(lenId);
|
|
if (lenInst->opcode() != SpvOpConstant) return 0;
|
|
uint32_t lenTypeId = lenInst->type_id();
|
|
Instruction* lenTypeInst = get_def_use_mgr()->GetDef(lenTypeId);
|
|
// TODO(greg-lunarg): Support non-32-bit array length
|
|
if (lenTypeInst->GetSingleWordInOperand(kTypeIntWidthInIdx) != 32)
|
|
return 0;
|
|
return lenInst->GetSingleWordInOperand(kConstantValueInIdx);
|
|
} break;
|
|
case SpvOpTypeStruct: {
|
|
return typeInst->NumInOperands();
|
|
} break;
|
|
default: { return 0; } break;
|
|
}
|
|
}
|
|
|
|
void DeadInsertElimPass::MarkInsertChain(
|
|
Instruction* insertChain, std::vector<uint32_t>* pExtIndices,
|
|
uint32_t extOffset, std::unordered_set<uint32_t>* visited_phis) {
|
|
// Not currently optimizing array inserts.
|
|
Instruction* typeInst = get_def_use_mgr()->GetDef(insertChain->type_id());
|
|
if (typeInst->opcode() == SpvOpTypeArray) return;
|
|
// Insert chains are only composed of inserts and phis
|
|
if (insertChain->opcode() != SpvOpCompositeInsert &&
|
|
insertChain->opcode() != SpvOpPhi)
|
|
return;
|
|
// If extract indices are empty, mark all subcomponents if type
|
|
// is constant length.
|
|
if (pExtIndices == nullptr) {
|
|
uint32_t cnum = NumComponents(typeInst);
|
|
if (cnum > 0) {
|
|
std::vector<uint32_t> extIndices;
|
|
for (uint32_t i = 0; i < cnum; i++) {
|
|
extIndices.clear();
|
|
extIndices.push_back(i);
|
|
std::unordered_set<uint32_t> sub_visited_phis;
|
|
MarkInsertChain(insertChain, &extIndices, 0, &sub_visited_phis);
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
Instruction* insInst = insertChain;
|
|
while (insInst->opcode() == SpvOpCompositeInsert) {
|
|
// If no extract indices, mark insert and inserted object (which might
|
|
// also be an insert chain) and continue up the chain though the input
|
|
// composite.
|
|
//
|
|
// Note: We mark inserted objects in this function (rather than in
|
|
// EliminateDeadInsertsOnePass) because in some cases, we can do it
|
|
// more accurately here.
|
|
if (pExtIndices == nullptr) {
|
|
liveInserts_.insert(insInst->result_id());
|
|
uint32_t objId = insInst->GetSingleWordInOperand(kInsertObjectIdInIdx);
|
|
std::unordered_set<uint32_t> obj_visited_phis;
|
|
MarkInsertChain(get_def_use_mgr()->GetDef(objId), nullptr, 0,
|
|
&obj_visited_phis);
|
|
// If extract indices match insert, we are done. Mark insert and
|
|
// inserted object.
|
|
} else if (ExtInsMatch(*pExtIndices, insInst, extOffset)) {
|
|
liveInserts_.insert(insInst->result_id());
|
|
uint32_t objId = insInst->GetSingleWordInOperand(kInsertObjectIdInIdx);
|
|
std::unordered_set<uint32_t> obj_visited_phis;
|
|
MarkInsertChain(get_def_use_mgr()->GetDef(objId), nullptr, 0,
|
|
&obj_visited_phis);
|
|
break;
|
|
// If non-matching intersection, mark insert
|
|
} else if (ExtInsConflict(*pExtIndices, insInst, extOffset)) {
|
|
liveInserts_.insert(insInst->result_id());
|
|
// If more extract indices than insert, we are done. Use remaining
|
|
// extract indices to mark inserted object.
|
|
uint32_t numInsertIndices = insInst->NumInOperands() - 2;
|
|
if (pExtIndices->size() - extOffset > numInsertIndices) {
|
|
uint32_t objId = insInst->GetSingleWordInOperand(kInsertObjectIdInIdx);
|
|
std::unordered_set<uint32_t> obj_visited_phis;
|
|
MarkInsertChain(get_def_use_mgr()->GetDef(objId), pExtIndices,
|
|
extOffset + numInsertIndices, &obj_visited_phis);
|
|
break;
|
|
// If fewer extract indices than insert, also mark inserted object and
|
|
// continue up chain.
|
|
} else {
|
|
uint32_t objId = insInst->GetSingleWordInOperand(kInsertObjectIdInIdx);
|
|
std::unordered_set<uint32_t> obj_visited_phis;
|
|
MarkInsertChain(get_def_use_mgr()->GetDef(objId), nullptr, 0,
|
|
&obj_visited_phis);
|
|
}
|
|
}
|
|
// Get next insert in chain
|
|
const uint32_t compId =
|
|
insInst->GetSingleWordInOperand(kInsertCompositeIdInIdx);
|
|
insInst = get_def_use_mgr()->GetDef(compId);
|
|
}
|
|
// If insert chain ended with phi, do recursive call on each operand
|
|
if (insInst->opcode() != SpvOpPhi) return;
|
|
// Mark phi visited to prevent potential infinite loop. If phi is already
|
|
// visited, return to avoid infinite loop.
|
|
if (visited_phis->count(insInst->result_id()) != 0) return;
|
|
visited_phis->insert(insInst->result_id());
|
|
|
|
// Phis may have duplicate inputs values for different edges, prune incoming
|
|
// ids lists before recursing.
|
|
std::vector<uint32_t> ids;
|
|
for (uint32_t i = 0; i < insInst->NumInOperands(); i += 2) {
|
|
ids.push_back(insInst->GetSingleWordInOperand(i));
|
|
}
|
|
std::sort(ids.begin(), ids.end());
|
|
auto new_end = std::unique(ids.begin(), ids.end());
|
|
for (auto id_iter = ids.begin(); id_iter != new_end; ++id_iter) {
|
|
Instruction* pi = get_def_use_mgr()->GetDef(*id_iter);
|
|
MarkInsertChain(pi, pExtIndices, extOffset, visited_phis);
|
|
}
|
|
}
|
|
|
|
bool DeadInsertElimPass::EliminateDeadInserts(Function* func) {
|
|
bool modified = false;
|
|
bool lastmodified = true;
|
|
// Each pass can delete dead instructions, thus potentially revealing
|
|
// new dead insertions ie insertions with no uses.
|
|
while (lastmodified) {
|
|
lastmodified = EliminateDeadInsertsOnePass(func);
|
|
modified |= lastmodified;
|
|
}
|
|
return modified;
|
|
}
|
|
|
|
bool DeadInsertElimPass::EliminateDeadInsertsOnePass(Function* func) {
|
|
bool modified = false;
|
|
liveInserts_.clear();
|
|
visitedPhis_.clear();
|
|
// Mark all live inserts
|
|
for (auto bi = func->begin(); bi != func->end(); ++bi) {
|
|
for (auto ii = bi->begin(); ii != bi->end(); ++ii) {
|
|
// Only process Inserts and composite Phis
|
|
SpvOp op = ii->opcode();
|
|
Instruction* typeInst = get_def_use_mgr()->GetDef(ii->type_id());
|
|
if (op != SpvOpCompositeInsert &&
|
|
(op != SpvOpPhi || !spvOpcodeIsComposite(typeInst->opcode())))
|
|
continue;
|
|
// The marking algorithm can be expensive for large arrays and the
|
|
// efficacy of eliminating dead inserts into arrays is questionable.
|
|
// Skip optimizing array inserts for now. Just mark them live.
|
|
// TODO(greg-lunarg): Eliminate dead array inserts
|
|
if (op == SpvOpCompositeInsert) {
|
|
if (typeInst->opcode() == SpvOpTypeArray) {
|
|
liveInserts_.insert(ii->result_id());
|
|
continue;
|
|
}
|
|
}
|
|
const uint32_t id = ii->result_id();
|
|
get_def_use_mgr()->ForEachUser(id, [&ii, this](Instruction* user) {
|
|
if (user->IsOpenCL100DebugInstr()) return;
|
|
switch (user->opcode()) {
|
|
case SpvOpCompositeInsert:
|
|
case SpvOpPhi:
|
|
// Use by insert or phi does not initiate marking
|
|
break;
|
|
case SpvOpCompositeExtract: {
|
|
// Capture extract indices
|
|
std::vector<uint32_t> extIndices;
|
|
uint32_t icnt = 0;
|
|
user->ForEachInOperand([&icnt, &extIndices](const uint32_t* idp) {
|
|
if (icnt > 0) extIndices.push_back(*idp);
|
|
++icnt;
|
|
});
|
|
// Mark all inserts in chain that intersect with extract
|
|
std::unordered_set<uint32_t> visited_phis;
|
|
MarkInsertChain(&*ii, &extIndices, 0, &visited_phis);
|
|
} break;
|
|
default: {
|
|
// Mark inserts in chain for all components
|
|
MarkInsertChain(&*ii, nullptr, 0, nullptr);
|
|
} break;
|
|
}
|
|
});
|
|
}
|
|
}
|
|
// Find and disconnect dead inserts
|
|
std::vector<Instruction*> dead_instructions;
|
|
for (auto bi = func->begin(); bi != func->end(); ++bi) {
|
|
for (auto ii = bi->begin(); ii != bi->end(); ++ii) {
|
|
if (ii->opcode() != SpvOpCompositeInsert) continue;
|
|
const uint32_t id = ii->result_id();
|
|
if (liveInserts_.find(id) != liveInserts_.end()) continue;
|
|
const uint32_t replId =
|
|
ii->GetSingleWordInOperand(kInsertCompositeIdInIdx);
|
|
(void)context()->ReplaceAllUsesWith(id, replId);
|
|
dead_instructions.push_back(&*ii);
|
|
modified = true;
|
|
}
|
|
}
|
|
// DCE dead inserts
|
|
while (!dead_instructions.empty()) {
|
|
Instruction* inst = dead_instructions.back();
|
|
dead_instructions.pop_back();
|
|
DCEInst(inst, [&dead_instructions](Instruction* other_inst) {
|
|
auto i = std::find(dead_instructions.begin(), dead_instructions.end(),
|
|
other_inst);
|
|
if (i != dead_instructions.end()) {
|
|
dead_instructions.erase(i);
|
|
}
|
|
});
|
|
}
|
|
return modified;
|
|
}
|
|
|
|
Pass::Status DeadInsertElimPass::Process() {
|
|
// Process all entry point functions.
|
|
ProcessFunction pfn = [this](Function* fp) {
|
|
return EliminateDeadInserts(fp);
|
|
};
|
|
bool modified = context()->ProcessEntryPointCallTree(pfn);
|
|
return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
|
|
}
|
|
|
|
} // namespace opt
|
|
} // namespace spvtools
|