SPIRV-Tools/source/opt/local_single_block_elim_pass.cpp
GregF c8c86a0d36 Opt: Have "size" passes process full entry point call tree.
Includes code to deal correctly with OpFunctionParameter. This
is needed by opaque propagation which may not exhaustively inline
entry point functions.

Adds ProcessEntryPointCallTree: a method to do work on the
functions in the entry point call trees in a deterministic order.
2017-08-18 10:16:01 -04:00

236 lines
7.5 KiB
C++

// Copyright (c) 2017 The Khronos Group Inc.
// Copyright (c) 2017 Valve Corporation
// Copyright (c) 2017 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 "local_single_block_elim_pass.h"
#include "iterator.h"
namespace spvtools {
namespace opt {
namespace {
const uint32_t kStoreValIdInIdx = 1;
} // anonymous namespace
bool LocalSingleBlockLoadStoreElimPass::HasOnlySupportedRefs(uint32_t ptrId) {
if (supported_ref_ptrs_.find(ptrId) != supported_ref_ptrs_.end())
return true;
analysis::UseList* uses = def_use_mgr_->GetUses(ptrId);
assert(uses != nullptr);
for (auto u : *uses) {
SpvOp op = u.inst->opcode();
if (IsNonPtrAccessChain(op) || op == SpvOpCopyObject) {
if (!HasOnlySupportedRefs(u.inst->result_id())) return false;
} else if (op != SpvOpStore && op != SpvOpLoad && op != SpvOpName &&
!IsNonTypeDecorate(op))
return false;
}
supported_ref_ptrs_.insert(ptrId);
return true;
}
bool LocalSingleBlockLoadStoreElimPass::LocalSingleBlockLoadStoreElim(
ir::Function* func) {
// Perform local store/load and load/load elimination on each block
bool modified = false;
for (auto bi = func->begin(); bi != func->end(); ++bi) {
var2store_.clear();
var2load_.clear();
pinned_vars_.clear();
for (auto ii = bi->begin(); ii != bi->end(); ++ii) {
switch (ii->opcode()) {
case SpvOpStore: {
// Verify store variable is target type
uint32_t varId;
ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
if (!IsTargetVar(varId))
continue;
if (!HasOnlySupportedRefs(varId))
continue;
// Register the store
if (ptrInst->opcode() == SpvOpVariable) {
// if not pinned, look for WAW
if (pinned_vars_.find(varId) == pinned_vars_.end()) {
auto si = var2store_.find(varId);
if (si != var2store_.end()) {
def_use_mgr_->KillInst(si->second);
}
}
var2store_[varId] = &*ii;
}
else {
assert(IsNonPtrAccessChain(ptrInst->opcode()));
var2store_.erase(varId);
}
pinned_vars_.erase(varId);
var2load_.erase(varId);
} break;
case SpvOpLoad: {
// Verify store variable is target type
uint32_t varId;
ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
if (!IsTargetVar(varId))
continue;
if (!HasOnlySupportedRefs(varId))
continue;
// Look for previous store or load
uint32_t replId = 0;
if (ptrInst->opcode() == SpvOpVariable) {
auto si = var2store_.find(varId);
if (si != var2store_.end()) {
replId = si->second->GetSingleWordInOperand(kStoreValIdInIdx);
}
else {
auto li = var2load_.find(varId);
if (li != var2load_.end()) {
replId = li->second->result_id();
}
}
}
if (replId != 0) {
// replace load's result id and delete load
ReplaceAndDeleteLoad(&*ii, replId);
modified = true;
}
else {
if (ptrInst->opcode() == SpvOpVariable)
var2load_[varId] = &*ii; // register load
pinned_vars_.insert(varId);
}
} break;
case SpvOpFunctionCall: {
// Conservatively assume all locals are redefined for now.
// TODO(): Handle more optimally
var2store_.clear();
var2load_.clear();
pinned_vars_.clear();
} break;
default:
break;
}
}
// Go back and delete useless stores in block
// TODO(greg-lunarg): Consider moving DCE into separate pass
for (auto ii = bi->begin(); ii != bi->end(); ++ii) {
if (ii->opcode() != SpvOpStore)
continue;
if (IsLiveStore(&*ii))
continue;
DCEInst(&*ii);
}
}
return modified;
}
void LocalSingleBlockLoadStoreElimPass::Initialize(ir::Module* module) {
module_ = module;
// Initialize Target Type Caches
seen_target_vars_.clear();
seen_non_target_vars_.clear();
// Clear collections
supported_ref_ptrs_.clear();
// TODO(greg-lunarg): Reuse def/use from previous passes
def_use_mgr_.reset(new analysis::DefUseManager(consumer(), module_));
// Start new ids with next availablein module
next_id_ = module_->id_bound();
// Initialize extensions whitelist
InitExtensions();
};
bool LocalSingleBlockLoadStoreElimPass::AllExtensionsSupported() const {
// If any extension not in whitelist, return false
for (auto& ei : module_->extensions()) {
const char* extName = reinterpret_cast<const char*>(
&ei.GetInOperand(0).words[0]);
if (extensions_whitelist_.find(extName) == extensions_whitelist_.end())
return false;
}
return true;
}
Pass::Status LocalSingleBlockLoadStoreElimPass::ProcessImpl() {
// Assumes logical addressing only
if (module_->HasCapability(SpvCapabilityAddresses))
return Status::SuccessWithoutChange;
// Do not process if module contains OpGroupDecorate. Additional
// support required in KillNamesAndDecorates().
// TODO(greg-lunarg): Add support for OpGroupDecorate
for (auto& ai : module_->annotations())
if (ai.opcode() == SpvOpGroupDecorate)
return Status::SuccessWithoutChange;
// If any extensions in the module are not explicitly supported,
// return unmodified.
if (!AllExtensionsSupported())
return Status::SuccessWithoutChange;
// Collect all named and decorated ids
FindNamedOrDecoratedIds();
// Process all entry point functions
ProcessFunction pfn = [this](ir::Function* fp) {
return LocalSingleBlockLoadStoreElim(fp);
};
bool modified = ProcessEntryPointCallTree(pfn, module_);
FinalizeNextId(module_);
return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
LocalSingleBlockLoadStoreElimPass::LocalSingleBlockLoadStoreElimPass()
: next_id_(0) {}
Pass::Status LocalSingleBlockLoadStoreElimPass::Process(ir::Module* module) {
Initialize(module);
return ProcessImpl();
}
void LocalSingleBlockLoadStoreElimPass::InitExtensions() {
extensions_whitelist_.clear();
extensions_whitelist_.insert({
"SPV_AMD_shader_explicit_vertex_parameter",
"SPV_AMD_shader_trinary_minmax",
"SPV_AMD_gcn_shader",
"SPV_KHR_shader_ballot",
"SPV_AMD_shader_ballot",
"SPV_AMD_gpu_shader_half_float",
"SPV_KHR_shader_draw_parameters",
"SPV_KHR_subgroup_vote",
"SPV_KHR_16bit_storage",
"SPV_KHR_device_group",
"SPV_KHR_multiview",
"SPV_NVX_multiview_per_view_attributes",
"SPV_NV_viewport_array2",
"SPV_NV_stereo_view_rendering",
"SPV_NV_sample_mask_override_coverage",
"SPV_NV_geometry_shader_passthrough",
"SPV_AMD_texture_gather_bias_lod",
"SPV_KHR_storage_buffer_storage_class",
// SPV_KHR_variable_pointers
// Currently do not support extended pointer expressions
"SPV_AMD_gpu_shader_int16",
"SPV_KHR_post_depth_coverage",
"SPV_KHR_shader_atomic_counter_ops",
});
}
} // namespace opt
} // namespace spvtools