SPIRV-Tools/source/opt/eliminate_dead_functions_util.cpp
alan-baker 5d2bc6f064
Fix removal of dependent non-semantic instructions (#5122)
Fixes #5121

* If the non-semantic info instructions depended on other moved
  instructions the def/use manager would get corrupted.
2023-02-24 01:10:35 +00:00

69 lines
2.5 KiB
C++

// Copyright (c) 2019 Google LLC
//
// 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 "eliminate_dead_functions_util.h"
namespace spvtools {
namespace opt {
namespace eliminatedeadfunctionsutil {
Module::iterator EliminateFunction(IRContext* context,
Module::iterator* func_iter) {
bool first_func = *func_iter == context->module()->begin();
bool seen_func_end = false;
std::unordered_set<Instruction*> to_kill;
(*func_iter)
->ForEachInst(
[context, first_func, func_iter, &seen_func_end,
&to_kill](Instruction* inst) {
if (inst->opcode() == spv::Op::OpFunctionEnd) {
seen_func_end = true;
}
// Move non-semantic instructions to the previous function or
// global values if this is the first function.
if (seen_func_end && inst->opcode() == spv::Op::OpExtInst) {
assert(inst->IsNonSemanticInstruction());
if (to_kill.find(inst) != to_kill.end()) return;
std::unique_ptr<Instruction> clone(inst->Clone(context));
// Clear uses of "inst" to in case this moves a dependent chain of
// instructions.
context->get_def_use_mgr()->ClearInst(inst);
context->AnalyzeDefUse(clone.get());
if (first_func) {
context->AddGlobalValue(std::move(clone));
} else {
auto prev_func_iter = *func_iter;
--prev_func_iter;
prev_func_iter->AddNonSemanticInstruction(std::move(clone));
}
inst->ToNop();
} else if (to_kill.find(inst) == to_kill.end()) {
context->CollectNonSemanticTree(inst, &to_kill);
context->KillInst(inst);
}
},
true, true);
for (auto* dead : to_kill) {
context->KillInst(dead);
}
return func_iter->Erase();
}
} // namespace eliminatedeadfunctionsutil
} // namespace opt
} // namespace spvtools