SPIRV-Tools/source/opt/interp_fixup_pass.cpp
Greg Fischer 9d1b572884
spirv-opt: (WIP) Eliminate Dead Input Component Pass (#4720)
This adds the --eliminate-dead-input-components pass which currently
removes trailing unused components from input arrays.

Fixes #4532
2022-03-22 20:50:52 -06:00

125 lines
4.1 KiB
C++

// Copyright (c) 2021 The Khronos Group Inc.
// Copyright (c) 2021 Valve Corporation
// Copyright (c) 2021 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/interp_fixup_pass.h"
#include <set>
#include <string>
#include "ir_builder.h"
#include "source/opt/ir_context.h"
#include "type_manager.h"
namespace spvtools {
namespace opt {
namespace {
// Input Operand Indices
static const int kSpvVariableStorageClassInIdx = 0;
// Folding rule function which attempts to replace |op(OpLoad(a),...)|
// by |op(a,...)|, where |op| is one of the GLSLstd450 InterpolateAt*
// instructions. Returns true if replaced, false otherwise.
bool ReplaceInternalInterpolate(IRContext* ctx, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
uint32_t glsl450_ext_inst_id =
ctx->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
assert(glsl450_ext_inst_id != 0);
uint32_t ext_opcode = inst->GetSingleWordInOperand(1);
uint32_t op1_id = inst->GetSingleWordInOperand(2);
Instruction* load_inst = ctx->get_def_use_mgr()->GetDef(op1_id);
if (load_inst->opcode() != SpvOpLoad) return false;
Instruction* base_inst = load_inst->GetBaseAddress();
USE_ASSERT(base_inst->opcode() == SpvOpVariable &&
base_inst->GetSingleWordInOperand(kSpvVariableStorageClassInIdx) ==
SpvStorageClassInput &&
"unexpected interpolant in InterpolateAt*");
uint32_t ptr_id = load_inst->GetSingleWordInOperand(0);
uint32_t op2_id = (ext_opcode != GLSLstd450InterpolateAtCentroid)
? inst->GetSingleWordInOperand(3)
: 0;
Instruction::OperandList new_operands;
new_operands.push_back({SPV_OPERAND_TYPE_ID, {glsl450_ext_inst_id}});
new_operands.push_back(
{SPV_OPERAND_TYPE_EXTENSION_INSTRUCTION_NUMBER, {ext_opcode}});
new_operands.push_back({SPV_OPERAND_TYPE_ID, {ptr_id}});
if (op2_id != 0) new_operands.push_back({SPV_OPERAND_TYPE_ID, {op2_id}});
inst->SetInOperands(std::move(new_operands));
ctx->UpdateDefUse(inst);
return true;
}
class InterpFoldingRules : public FoldingRules {
public:
explicit InterpFoldingRules(IRContext* ctx) : FoldingRules(ctx) {}
protected:
virtual void AddFoldingRules() override {
uint32_t extension_id =
context()->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
if (extension_id != 0) {
ext_rules_[{extension_id, GLSLstd450InterpolateAtCentroid}].push_back(
ReplaceInternalInterpolate);
ext_rules_[{extension_id, GLSLstd450InterpolateAtSample}].push_back(
ReplaceInternalInterpolate);
ext_rules_[{extension_id, GLSLstd450InterpolateAtOffset}].push_back(
ReplaceInternalInterpolate);
}
}
};
class InterpConstFoldingRules : public ConstantFoldingRules {
public:
InterpConstFoldingRules(IRContext* ctx) : ConstantFoldingRules(ctx) {}
protected:
virtual void AddFoldingRules() override {}
};
} // namespace
Pass::Status InterpFixupPass::Process() {
bool changed = false;
// Traverse the body of the functions to replace instructions that require
// the extensions.
InstructionFolder folder(
context(),
std::unique_ptr<InterpFoldingRules>(new InterpFoldingRules(context())),
MakeUnique<InterpConstFoldingRules>(context()));
for (Function& func : *get_module()) {
func.ForEachInst([&changed, &folder](Instruction* inst) {
if (folder.FoldInstruction(inst)) {
changed = true;
}
});
}
return changed ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
} // namespace opt
} // namespace spvtools