mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-11-23 20:20:06 +00:00
34d4294c2c
We have come across a driver bug where and OpUnreachable inside a loop is causing the shader to go into an infinite loop. This commit will try to avoid this bug by turning OpUnreachable instructions that are contained in a loop into branches to the loop merge block. This is not added to "-O" and "-Os" because it should only be used if the driver being targeted has this problem. Fixes #1209.
69 lines
2.3 KiB
C++
69 lines
2.3 KiB
C++
// Copyright (c) 2018 Google 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 "workaround1209.h"
|
|
|
|
#include <list>
|
|
#include <stack>
|
|
|
|
namespace spvtools {
|
|
namespace opt {
|
|
|
|
Pass::Status Workaround1209::Process(ir::IRContext* c) {
|
|
InitializeProcessing(c);
|
|
bool modified = false;
|
|
modified = RemoveOpUnreachableInLoops();
|
|
return (modified ? Status::SuccessWithChange : Status::SuccessWithoutChange);
|
|
}
|
|
|
|
bool Workaround1209::RemoveOpUnreachableInLoops() {
|
|
bool modified = false;
|
|
for (auto& func : *get_module()) {
|
|
std::list<ir::BasicBlock*> structured_order;
|
|
cfg()->ComputeStructuredOrder(&func, &*func.begin(), &structured_order);
|
|
|
|
// Keep track of the loop merges. The top of the stack will always be the
|
|
// loop merge for the loop that immediately contains the basic block being
|
|
// processed.
|
|
std::stack<uint32_t> loop_merges;
|
|
for (ir::BasicBlock* bb : structured_order) {
|
|
if (!loop_merges.empty() && bb->id() == loop_merges.top()) {
|
|
loop_merges.pop();
|
|
}
|
|
|
|
if (bb->tail()->opcode() == SpvOpUnreachable) {
|
|
if (!loop_merges.empty()) {
|
|
// We found an OpUnreachable inside a loop.
|
|
// Replace it with an unconditional branch to the loop merge.
|
|
context()->KillInst(&*bb->tail());
|
|
std::unique_ptr<ir::Instruction> new_branch(
|
|
new ir::Instruction(context(), SpvOpBranch, 0, 0,
|
|
{{spv_operand_type_t::SPV_OPERAND_TYPE_ID,
|
|
{loop_merges.top()}}}));
|
|
context()->AnalyzeDefUse(&*new_branch);
|
|
bb->AddInstruction(std::move(new_branch));
|
|
modified = true;
|
|
}
|
|
} else {
|
|
if (bb->GetLoopMergeInst()) {
|
|
loop_merges.push(bb->MergeBlockIdIfAny());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return modified;
|
|
}
|
|
} // namespace opt
|
|
} // namespace spvtools
|