// 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 "source/opt/inline_pass.h"
#include <unordered_set>
#include <utility>
#include "source/cfa.h"
#include "source/util/make_unique.h"
// Indices of operands in SPIR-V instructions
static const int kSpvFunctionCallFunctionId = 2;
static const int kSpvFunctionCallArgumentId = 3;
static const int kSpvReturnValueId = 0;
static const int kSpvLoopMergeContinueTargetIdInIdx = 1;
namespace spvtools {
namespace opt {
uint32_t InlinePass::AddPointerToType(uint32_t type_id,
SpvStorageClass storage_class) {
uint32_t resultId = context()->TakeNextId();
if (resultId == 0) {
return resultId;
}
std::unique_ptr<Instruction> type_inst(
new Instruction(context(), SpvOpTypePointer, 0, resultId,
{{spv_operand_type_t::SPV_OPERAND_TYPE_STORAGE_CLASS,
{uint32_t(storage_class)}},
{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {type_id}}}));
context()->AddType(std::move(type_inst));
analysis::Type* pointeeTy;
std::unique_ptr<analysis::Pointer> pointerTy;
std::tie(pointeeTy, pointerTy) =
context()->get_type_mgr()->GetTypeAndPointerType(type_id,
SpvStorageClassFunction);
context()->get_type_mgr()->RegisterType(resultId, *pointerTy);
return resultId;
}
void InlinePass::AddBranch(uint32_t label_id,
std::unique_ptr<BasicBlock>* block_ptr) {
std::unique_ptr<Instruction> newBranch(
new Instruction(context(), SpvOpBranch, 0, 0,
{{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {label_id}}}));
(*block_ptr)->AddInstruction(std::move(newBranch));
}
void InlinePass::AddBranchCond(uint32_t cond_id, uint32_t true_id,
uint32_t false_id,
std::unique_ptr<BasicBlock>* block_ptr) {
std::unique_ptr<Instruction> newBranch(
new Instruction(context(), SpvOpBranchConditional, 0, 0,
{{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {cond_id}},
{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {true_id}},
{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {false_id}}}));
(*block_ptr)->AddInstruction(std::move(newBranch));
}
void InlinePass::AddLoopMerge(uint32_t merge_id, uint32_t continue_id,
std::unique_ptr<BasicBlock>* block_ptr) {
std::unique_ptr<Instruction> newLoopMerge(new Instruction(
context(), SpvOpLoopMerge, 0, 0,
{{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {merge_id}},
{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {continue_id}},
{spv_operand_type_t::SPV_OPERAND_TYPE_LOOP_CONTROL, {0}}}));
(*block_ptr)->AddInstruction(std::move(newLoopMerge));
}
void InlinePass::AddStore(uint32_t ptr_id, uint32_t val_id,
std::unique_ptr<BasicBlock>* block_ptr) {
std::unique_ptr<Instruction> newStore(
new Instruction(context(), SpvOpStore, 0, 0,
{{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {ptr_id}},
{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {val_id}}}));
(*block_ptr)->AddInstruction(std::move(newStore));
}
void InlinePass::AddLoad(uint32_t type_id, uint32_t resultId, uint32_t ptr_id,
std::unique_ptr<BasicBlock>* block_ptr) {
std::unique_ptr<Instruction> newLoad(
new Instruction(context(), SpvOpLoad, type_id, resultId,
{{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {ptr_id}}}));
(*block_ptr)->AddInstruction(std::move(newLoad));
}
std::unique_ptr<Instruction> InlinePass::NewLabel(uint32_t label_id) {
std::unique_ptr<Instruction> newLabel(
new Instruction(context(), SpvOpLabel, 0, label_id, {}));
return newLabel;
}
uint32_t InlinePass::GetFalseId() {
if (false_id_ != 0) return false_id_;
false_id_ = get_module()->GetGlobalValue(SpvOpConstantFalse);
if (false_id_ != 0) return false_id_;
uint32_t boolId = get_module()->GetGlobalValue(SpvOpTypeBool);
if (boolId == 0) {
boolId = context()->TakeNextId();
if (boolId == 0) {
return 0;
}
get_module()->AddGlobalValue(SpvOpTypeBool, boolId, 0);
}
false_id_ = context()->TakeNextId();
if (false_id_ == 0) {
return 0;
}
get_module()->AddGlobalValue(SpvOpConstantFalse, false_id_, boolId);
return false_id_;
}
void InlinePass::MapParams(
Function* calleeFn, BasicBlock::iterator call_inst_itr,
std::unordered_map<uint32_t, uint32_t>* callee2caller) {
int param_idx = 0;
calleeFn->ForEachParam(
[&call_inst_itr, ¶m_idx, &callee2caller](const Instruction* cpi) {
const uint32_t pid = cpi->result_id();
(*callee2caller)[pid] = call_inst_itr->GetSingleWordOperand(
kSpvFunctionCallArgumentId + param_idx);
++param_idx;
});
}
bool InlinePass::CloneAndMapLocals(
Function* calleeFn, std::vector<std::unique_ptr<Instruction>>* new_vars,
std::unordered_map<uint32_t, uint32_t>* callee2caller) {
auto callee_block_itr = calleeFn->begin();
auto callee_var_itr = callee_block_itr->begin();
while (callee_var_itr->opcode() == SpvOp::SpvOpVariable) {
std::unique_ptr<Instruction> var_inst(callee_var_itr->Clone(context()));
uint32_t newId = context()->TakeNextId();
if (newId == 0) {
return false;
}
get_decoration_mgr()->CloneDecorations(callee_var_itr->result_id(), newId);
var_inst->SetResultId(newId);
(*callee2caller)[callee_var_itr->result_id()] = newId;
new_vars->push_back(std::move(var_inst));
++callee_var_itr;
}
return true;
}
uint32_t InlinePass::CreateReturnVar(
Function* calleeFn, std::vector<std::unique_ptr<Instruction>>* new_vars) {
uint32_t returnVarId = 0;
const uint32_t calleeTypeId = calleeFn->type_id();
analysis::TypeManager* type_mgr = context()->get_type_mgr();
assert(type_mgr->GetType(calleeTypeId)->AsVoid() == nullptr &&
"Cannot create a return variable of type void.");
// Find or create ptr to callee return type.
uint32_t returnVarTypeId =
type_mgr->FindPointerToType(calleeTypeId, SpvStorageClassFunction);
if (returnVarTypeId == 0) {
returnVarTypeId = AddPointerToType(calleeTypeId, SpvStorageClassFunction);
if (returnVarTypeId == 0) {
return 0;
}
}
// Add return var to new function scope variables.
returnVarId = context()->TakeNextId();
if (returnVarId == 0) {
return 0;
}
std::unique_ptr<Instruction> var_inst(
new Instruction(context(), SpvOpVariable, returnVarTypeId, returnVarId,
{{spv_operand_type_t::SPV_OPERAND_TYPE_STORAGE_CLASS,
{SpvStorageClassFunction}}}));
new_vars->push_back(std::move(var_inst));
get_decoration_mgr()->CloneDecorations(calleeFn->result_id(), returnVarId);
return returnVarId;
}
bool InlinePass::IsSameBlockOp(const Instruction* inst) const {
return inst->opcode() == SpvOpSampledImage || inst->opcode() == SpvOpImage;
}
bool InlinePass::CloneSameBlockOps(
std::unique_ptr<Instruction>* inst,
std::unordered_map<uint32_t, uint32_t>* postCallSB,
std::unordered_map<uint32_t, Instruction*>* preCallSB,
std::unique_ptr<BasicBlock>* block_ptr) {
return (*inst)->WhileEachInId([&postCallSB, &preCallSB, &block_ptr,
this](uint32_t* iid) {
const auto mapItr = (*postCallSB).find(*iid);
if (mapItr == (*postCallSB).end()) {
const auto mapItr2 = (*preCallSB).find(*iid);
if (mapItr2 != (*preCallSB).end()) {
// Clone pre-call same-block ops, map result id.
const Instruction* inInst = mapItr2->second;
std::unique_ptr<Instruction> sb_inst(inInst->Clone(context()));
if (!CloneSameBlockOps(&sb_inst, postCallSB, preCallSB, block_ptr)) {
return false;
}
const uint32_t rid = sb_inst->result_id();
const uint32_t nid = context()->TakeNextId();
if (nid == 0) {
return false;
}
get_decoration_mgr()->CloneDecorations(rid, nid);
sb_inst->SetResultId(nid);
(*postCallSB)[rid] = nid;
*iid = nid;
(*block_ptr)->AddInstruction(std::move(sb_inst));
}
} else {
// Reset same-block op operand.
*iid = mapItr->second;
}
return true;
});
}
bool InlinePass::GenInlineCode(
std::vector<std::unique_ptr<BasicBlock>>* new_blocks,
std::vector<std::unique_ptr<Instruction>>* new_vars,
BasicBlock::iterator call_inst_itr,
UptrVectorIterator<BasicBlock> call_block_itr) {
// Map from all ids in the callee to their equivalent id in the caller
// as callee instructions are copied into caller.
std::unordered_map<uint32_t, uint32_t> callee2caller;
// Pre-call same-block insts
std::unordered_map<uint32_t, Instruction*> preCallSB;
// Post-call same-block op ids
std::unordered_map<uint32_t, uint32_t> postCallSB;
// Invalidate the def-use chains. They are not kept up to date while
// inlining. However, certain calls try to keep them up-to-date if they are
// valid. These operations can fail.
context()->InvalidateAnalyses(IRContext::kAnalysisDefUse);
Function* calleeFn = id2function_[call_inst_itr->GetSingleWordOperand(
kSpvFunctionCallFunctionId)];
// Check for multiple returns in the callee.
auto fi = early_return_funcs_.find(calleeFn->result_id());
const bool earlyReturn = fi != early_return_funcs_.end();
// Map parameters to actual arguments.
MapParams(calleeFn, call_inst_itr, &callee2caller);
// Define caller local variables for all callee variables and create map to
// them.
if (!CloneAndMapLocals(calleeFn, new_vars, &callee2caller)) {
return false;
}
// Create return var if needed.
const uint32_t calleeTypeId = calleeFn->type_id();
uint32_t returnVarId = 0;
analysis::Type* calleeType = context()->get_type_mgr()->GetType(calleeTypeId);
if (calleeType->AsVoid() == nullptr) {
returnVarId = CreateReturnVar(calleeFn, new_vars);
if (returnVarId == 0) {
return false;
}
}
// Create set of callee result ids. Used to detect forward references
std::unordered_set<uint32_t> callee_result_ids;
calleeFn->ForEachInst([&callee_result_ids](const Instruction* cpi) {
const uint32_t rid = cpi->result_id();
if (rid != 0) callee_result_ids.insert(rid);
});
// If the caller is in a single-block loop, and the callee has multiple
// blocks, then the normal inlining logic will place the OpLoopMerge in
// the last of several blocks in the loop. Instead, it should be placed
// at the end of the first block. First determine if the caller is in a
// single block loop. We'll wait to move the OpLoopMerge until the end
// of the regular inlining logic, and only if necessary.
bool caller_is_single_block_loop = false;
bool caller_is_loop_header = false;
if (auto* loop_merge = call_block_itr->GetLoopMergeInst()) {
caller_is_loop_header = true;
caller_is_single_block_loop =
call_block_itr->id() ==
loop_merge->GetSingleWordInOperand(kSpvLoopMergeContinueTargetIdInIdx);
}
bool callee_begins_with_structured_header =
(*(calleeFn->begin())).GetMergeInst() != nullptr;
// Clone and map callee code. Copy caller block code to beginning of
// first block and end of last block.
bool prevInstWasReturn = false;
uint32_t singleTripLoopHeaderId = 0;
uint32_t singleTripLoopContinueId = 0;
uint32_t returnLabelId = 0;
bool multiBlocks = false;
// new_blk_ptr is a new basic block in the caller. New instructions are
// written to it. It is created when we encounter the OpLabel
// of the first callee block. It is appended to new_blocks only when
// it is complete.
std::unique_ptr<BasicBlock> new_blk_ptr;
bool successful = calleeFn->WhileEachInst(
[&new_blocks, &callee2caller, &call_block_itr, &call_inst_itr,
&new_blk_ptr, &prevInstWasReturn, &returnLabelId, &returnVarId,
caller_is_loop_header, callee_begins_with_structured_header,
&calleeTypeId, &multiBlocks, &postCallSB, &preCallSB, earlyReturn,
&singleTripLoopHeaderId, &singleTripLoopContinueId, &callee_result_ids,
this](const Instruction* cpi) {
switch (cpi->opcode()) {
case SpvOpFunction:
case SpvOpFunctionParameter:
// Already processed
break;
case SpvOpVariable:
if (cpi->NumInOperands() == 2) {
assert(callee2caller.count(cpi->result_id()) &&
"Expected the variable to have already been mapped.");
uint32_t new_var_id = callee2caller.at(cpi->result_id());
// The initializer must be a constant or global value. No mapped
// should be used.
uint32_t val_id = cpi->GetSingleWordInOperand(1);
AddStore(new_var_id, val_id, &new_blk_ptr);
}
break;
case SpvOpUnreachable:
case SpvOpKill: {
// Generate a return label so that we split the block with the
// function call. Copy the terminator into the new block.
if (returnLabelId == 0) {
returnLabelId = context()->TakeNextId();
if (returnLabelId == 0) {
return false;
}
}
std::unique_ptr<Instruction> terminator(
new Instruction(context(), cpi->opcode(), 0, 0, {}));
new_blk_ptr->AddInstruction(std::move(terminator));
break;
}
case SpvOpLabel: {
// If previous instruction was early return, insert branch
// instruction to return block.
if (prevInstWasReturn) {
if (returnLabelId == 0) {
returnLabelId = context()->TakeNextId();
if (returnLabelId == 0) {
return false;
}
}
AddBranch(returnLabelId, &new_blk_ptr);
prevInstWasReturn = false;
}
// Finish current block (if it exists) and get label for next block.
uint32_t labelId;
bool firstBlock = false;
if (new_blk_ptr != nullptr) {
new_blocks->push_back(std::move(new_blk_ptr));
// If result id is already mapped, use it, otherwise get a new
// one.
const uint32_t rid = cpi->result_id();
const auto mapItr = callee2caller.find(rid);
labelId = (mapItr != callee2caller.end())
? mapItr->second
: context()->TakeNextId();
if (labelId == 0) {
return false;
}
} else {
// First block needs to use label of original block
// but map callee label in case of phi reference.
labelId = call_block_itr->id();
callee2caller[cpi->result_id()] = labelId;
firstBlock = true;
}
// Create first/next block.
new_blk_ptr = MakeUnique<BasicBlock>(NewLabel(labelId));
if (firstBlock) {
// Copy contents of original caller block up to call instruction.
for (auto cii = call_block_itr->begin(); cii != call_inst_itr;
cii = call_block_itr->begin()) {
Instruction* inst = &*cii;
inst->RemoveFromList();
std::unique_ptr<Instruction> cp_inst(inst);
// Remember same-block ops for possible regeneration.
if (IsSameBlockOp(&*cp_inst)) {
auto* sb_inst_ptr = cp_inst.get();
preCallSB[cp_inst->result_id()] = sb_inst_ptr;
}
new_blk_ptr->AddInstruction(std::move(cp_inst));
}
if (caller_is_loop_header &&
callee_begins_with_structured_header) {
// We can't place both the caller's merge instruction and
// another merge instruction in the same block. So split the
// calling block. Insert an unconditional branch to a new guard
// block. Later, once we know the ID of the last block, we
// will move the caller's OpLoopMerge from the last generated
// block into the first block. We also wait to avoid
// invalidating various iterators.
const auto guard_block_id = context()->TakeNextId();
if (guard_block_id == 0) {
return false;
}
AddBranch(guard_block_id, &new_blk_ptr);
new_blocks->push_back(std::move(new_blk_ptr));
// Start the next block.
new_blk_ptr = MakeUnique<BasicBlock>(NewLabel(guard_block_id));
// Reset the mapping of the callee's entry block to point to
// the guard block. Do this so we can fix up phis later on to
// satisfy dominance.
callee2caller[cpi->result_id()] = guard_block_id;
}
// If callee has early return, insert a header block for
// single-trip loop that will encompass callee code. Start
// postheader block.
//
// Note: Consider the following combination:
// - the caller is a single block loop
// - the callee does not begin with a structure header
// - the callee has multiple returns.
// We still need to split the caller block and insert a guard
// block. But we only need to do it once. We haven't done it yet,
// but the single-trip loop header will serve the same purpose.
if (earlyReturn) {
singleTripLoopHeaderId = context()->TakeNextId();
if (singleTripLoopHeaderId == 0) {
return false;
}
AddBranch(singleTripLoopHeaderId, &new_blk_ptr);
new_blocks->push_back(std::move(new_blk_ptr));
new_blk_ptr =
MakeUnique<BasicBlock>(NewLabel(singleTripLoopHeaderId));
returnLabelId = context()->TakeNextId();
singleTripLoopContinueId = context()->TakeNextId();
if (returnLabelId == 0 || singleTripLoopContinueId == 0) {
return false;
}
AddLoopMerge(returnLabelId, singleTripLoopContinueId,
&new_blk_ptr);
uint32_t postHeaderId = context()->TakeNextId();
if (postHeaderId == 0) {
return false;
}
AddBranch(postHeaderId, &new_blk_ptr);
new_blocks->push_back(std::move(new_blk_ptr));
new_blk_ptr = MakeUnique<BasicBlock>(NewLabel(postHeaderId));
multiBlocks = true;
// Reset the mapping of the callee's entry block to point to
// the post-header block. Do this so we can fix up phis later
// on to satisfy dominance.
callee2caller[cpi->result_id()] = postHeaderId;
}
} else {
multiBlocks = true;
}
} break;
case SpvOpReturnValue: {
// Store return value to return variable.
assert(returnVarId != 0);
uint32_t valId = cpi->GetInOperand(kSpvReturnValueId).words[0];
const auto mapItr = callee2caller.find(valId);
if (mapItr != callee2caller.end()) {
valId = mapItr->second;
}
AddStore(returnVarId, valId, &new_blk_ptr);
// Remember we saw a return; if followed by a label, will need to
// insert branch.
prevInstWasReturn = true;
} break;
case SpvOpReturn: {
// Remember we saw a return; if followed by a label, will need to
// insert branch.
prevInstWasReturn = true;
} break;
case SpvOpFunctionEnd: {
// If there was an early return, we generated a return label id
// for it. Now we have to generate the return block with that Id.
if (returnLabelId != 0) {
// If previous instruction was return, insert branch instruction
// to return block.
if (prevInstWasReturn) AddBranch(returnLabelId, &new_blk_ptr);
if (earlyReturn) {
// If we generated a loop header for the single-trip loop
// to accommodate early returns, insert the continue
// target block now, with a false branch back to the loop
// header.
new_blocks->push_back(std::move(new_blk_ptr));
new_blk_ptr =
MakeUnique<BasicBlock>(NewLabel(singleTripLoopContinueId));
uint32_t false_id = GetFalseId();
if (false_id == 0) {
return false;
}
AddBranchCond(false_id, singleTripLoopHeaderId, returnLabelId,
&new_blk_ptr);
}
// Generate the return block.
new_blocks->push_back(std::move(new_blk_ptr));
new_blk_ptr = MakeUnique<BasicBlock>(NewLabel(returnLabelId));
multiBlocks = true;
}
// Load return value into result id of call, if it exists.
if (returnVarId != 0) {
const uint32_t resId = call_inst_itr->result_id();
assert(resId != 0);
AddLoad(calleeTypeId, resId, returnVarId, &new_blk_ptr);
}
// Copy remaining instructions from caller block.
for (Instruction* inst = call_inst_itr->NextNode(); inst;
inst = call_inst_itr->NextNode()) {
inst->RemoveFromList();
std::unique_ptr<Instruction> cp_inst(inst);
// If multiple blocks generated, regenerate any same-block
// instruction that has not been seen in this last block.
if (multiBlocks) {
if (!CloneSameBlockOps(&cp_inst, &postCallSB, &preCallSB,
&new_blk_ptr)) {
return false;
}
// Remember same-block ops in this block.
if (IsSameBlockOp(&*cp_inst)) {
const uint32_t rid = cp_inst->result_id();
postCallSB[rid] = rid;
}
}
new_blk_ptr->AddInstruction(std::move(cp_inst));
}
// Finalize inline code.
new_blocks->push_back(std::move(new_blk_ptr));
} break;
default: {
// Copy callee instruction and remap all input Ids.
std::unique_ptr<Instruction> cp_inst(cpi->Clone(context()));
bool succeeded = cp_inst->WhileEachInId(
[&callee2caller, &callee_result_ids, this](uint32_t* iid) {
const auto mapItr = callee2caller.find(*iid);
if (mapItr != callee2caller.end()) {
*iid = mapItr->second;
} else if (callee_result_ids.find(*iid) !=
callee_result_ids.end()) {
// Forward reference. Allocate a new id, map it,
// use it and check for it when remapping result ids
const uint32_t nid = context()->TakeNextId();
if (nid == 0) {
return false;
}
callee2caller[*iid] = nid;
*iid = nid;
}
return true;
});
if (!succeeded) {
return false;
}
// If result id is non-zero, remap it. If already mapped, use mapped
// value, else use next id.
const uint32_t rid = cp_inst->result_id();
if (rid != 0) {
const auto mapItr = callee2caller.find(rid);
uint32_t nid;
if (mapItr != callee2caller.end()) {
nid = mapItr->second;
} else {
nid = context()->TakeNextId();
if (nid == 0) {
return false;
}
callee2caller[rid] = nid;
}
cp_inst->SetResultId(nid);
get_decoration_mgr()->CloneDecorations(rid, nid);
}
new_blk_ptr->AddInstruction(std::move(cp_inst));
} break;
}
return true;
});
if (!successful) {
return false;
}
if (caller_is_loop_header && (new_blocks->size() > 1)) {
// Move the OpLoopMerge from the last block back to the first, where
// it belongs.
auto& first = new_blocks->front();
auto& last = new_blocks->back();
assert(first != last);
// Insert a modified copy of the loop merge into the first block.
auto loop_merge_itr = last->tail();
--loop_merge_itr;
assert(loop_merge_itr->opcode() == SpvOpLoopMerge);
std::unique_ptr<Instruction> cp_inst(loop_merge_itr->Clone(context()));
if (caller_is_single_block_loop) {
// Also, update its continue target to point to the last block.
cp_inst->SetInOperand(kSpvLoopMergeContinueTargetIdInIdx, {last->id()});
}
first->tail().InsertBefore(std::move(cp_inst));
// Remove the loop merge from the last block.
loop_merge_itr->RemoveFromList();
delete &*loop_merge_itr;
}
// Update block map given replacement blocks.
for (auto& blk : *new_blocks) {
id2block_[blk->id()] = &*blk;
}
return true;
}
bool InlinePass::IsInlinableFunctionCall(const Instruction* inst) {
if (inst->opcode() != SpvOp::SpvOpFunctionCall) return false;
const uint32_t calleeFnId =
inst->GetSingleWordOperand(kSpvFunctionCallFunctionId);
const auto ci = inlinable_.find(calleeFnId);
return ci != inlinable_.cend();
}
void InlinePass::UpdateSucceedingPhis(
std::vector<std::unique_ptr<BasicBlock>>& new_blocks) {
const auto firstBlk = new_blocks.begin();
const auto lastBlk = new_blocks.end() - 1;
const uint32_t firstId = (*firstBlk)->id();
const uint32_t lastId = (*lastBlk)->id();
const BasicBlock& const_last_block = *lastBlk->get();
const_last_block.ForEachSuccessorLabel(
[&firstId, &lastId, this](const uint32_t succ) {
BasicBlock* sbp = this->id2block_[succ];
sbp->ForEachPhiInst([&firstId, &lastId](Instruction* phi) {
phi->ForEachInId([&firstId, &lastId](uint32_t* id) {
if (*id == firstId) *id = lastId;
});
});
});
}
bool InlinePass::HasNoReturnInStructuredConstruct(Function* func) {
// If control not structured, do not do loop/return analysis
// TODO: Analyze returns in non-structured control flow
if (!context()->get_feature_mgr()->HasCapability(SpvCapabilityShader))
return false;
const auto structured_analysis = context()->GetStructuredCFGAnalysis();
// Search for returns in structured construct.
bool return_in_construct = false;
for (auto& blk : *func) {
auto terminal_ii = blk.cend();
--terminal_ii;
if (spvOpcodeIsReturn(terminal_ii->opcode()) &&
structured_analysis->ContainingConstruct(blk.id()) != 0) {
return_in_construct = true;
break;
}
}
return !return_in_construct;
}
bool InlinePass::HasNoReturnInLoop(Function* func) {
// If control not structured, do not do loop/return analysis
// TODO: Analyze returns in non-structured control flow
if (!context()->get_feature_mgr()->HasCapability(SpvCapabilityShader))
return false;
const auto structured_analysis = context()->GetStructuredCFGAnalysis();
// Search for returns in structured construct.
bool return_in_loop = false;
for (auto& blk : *func) {
auto terminal_ii = blk.cend();
--terminal_ii;
if (spvOpcodeIsReturn(terminal_ii->opcode()) &&
structured_analysis->ContainingLoop(blk.id()) != 0) {
return_in_loop = true;
break;
}
}
return !return_in_loop;
}
void InlinePass::AnalyzeReturns(Function* func) {
if (HasNoReturnInLoop(func)) {
no_return_in_loop_.insert(func->result_id());
if (!HasNoReturnInStructuredConstruct(func))
early_return_funcs_.insert(func->result_id());
}
}
bool InlinePass::IsInlinableFunction(Function* func) {
// We can only inline a function if it has blocks.
if (func->cbegin() == func->cend()) return false;
// Do not inline functions with returns in loops. Currently early return
// functions are inlined by wrapping them in a one trip loop and implementing
// the returns as a branch to the loop's merge block. However, this can only
// done validly if the return was not in a loop in the original function.
// Also remember functions with multiple (early) returns.
AnalyzeReturns(func);
if (no_return_in_loop_.find(func->result_id()) == no_return_in_loop_.cend()) {
return false;
}
if (func->IsRecursive()) {
return false;
}
return true;
}
void InlinePass::InitializeInline() {
false_id_ = 0;
// clear collections
id2function_.clear();
id2block_.clear();
inlinable_.clear();
no_return_in_loop_.clear();
early_return_funcs_.clear();
for (auto& fn : *get_module()) {
// Initialize function and block maps.
id2function_[fn.result_id()] = &fn;
for (auto& blk : fn) {
id2block_[blk.id()] = &blk;
}
// Compute inlinability
if (IsInlinableFunction(&fn)) inlinable_.insert(fn.result_id());
}
}
InlinePass::InlinePass() {}
} // namespace opt
} // namespace spvtools