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[backend-O1]RISCv64ISel对-O1新增专门的处理逻辑

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CGH0S7
2025-08-19 22:42:30 +08:00
parent ef68235446
commit 33388496d5
1 changed files with 101 additions and 0 deletions
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101
src/backend/RISCv64/RISCv64ISel.cpp
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@ -1311,6 +1311,7 @@ void RISCv64ISel::selectNode(DAGNode* node) {
auto gep = dynamic_cast<GetElementPtrInst*>(node->value);
auto result_vreg = getVReg(gep);
if (optLevel == 0) {
// --- Step 1: 获取基地址 (此部分逻辑正确，保持不变) ---
auto base_ptr_node = node->operands[0];
auto current_addr_vreg = getNewVReg(gep->getType());
@ -1417,6 +1418,106 @@ void RISCv64ISel::selectNode(DAGNode* node) {
final_mv->addOperand(std::make_unique<RegOperand>(current_addr_vreg));
CurMBB->addInstruction(std::move(final_mv));
break;
} else {
// 对于-O1时的处理逻辑
// --- Step 1: 获取基地址 ---
auto base_ptr_node = node->operands[0];
auto base_ptr_val = base_ptr_node->value;
// last_step_addr_vreg 保存上一步计算的结果。
// 它首先被初始化为GEP的初始基地址。
unsigned last_step_addr_vreg;
if (auto alloca_base = dynamic_cast<AllocaInst*>(base_ptr_val)) {
last_step_addr_vreg = getNewVReg(gep->getType());
auto frame_addr_instr = std::make_unique<MachineInstr>(RVOpcodes::FRAME_ADDR);
frame_addr_instr->addOperand(std::make_unique<RegOperand>(last_step_addr_vreg));
frame_addr_instr->addOperand(std::make_unique<RegOperand>(getVReg(alloca_base)));
CurMBB->addInstruction(std::move(frame_addr_instr));
} else if (auto global_base = dynamic_cast<GlobalValue*>(base_ptr_val)) {
last_step_addr_vreg = getNewVReg(gep->getType());
auto la_instr = std::make_unique<MachineInstr>(RVOpcodes::LA);
la_instr->addOperand(std::make_unique<RegOperand>(last_step_addr_vreg));
la_instr->addOperand(std::make_unique<LabelOperand>(global_base->getName()));
CurMBB->addInstruction(std::move(la_instr));
} else {
// 对于函数参数或来自其他指令的指针，直接获取其vreg。
// 这个vreg必须被保护，不能在计算中被修改。
last_step_addr_vreg = getVReg(base_ptr_val);
}
// --- Step 2: 遵循LLVM GEP语义迭代计算地址 ---
Type* current_type = gep->getBasePointer()->getType()->as<PointerType>()->getBaseType();
for (size_t i = 0; i < gep->getNumIndices(); ++i) {
Value* indexValue = gep->getIndex(i);
unsigned stride = getTypeSizeInBytes(current_type);
if (stride != 0) {
// --- 为当前索引和步长生成偏移计算指令 ---
auto offset_vreg = getNewVReg(Type::getIntType());
unsigned index_vreg;
if (auto const_index = dynamic_cast<ConstantValue*>(indexValue)) {
index_vreg = getNewVReg(Type::getIntType());
auto li = std::make_unique<MachineInstr>(RVOpcodes::LI);
li->addOperand(std::make_unique<RegOperand>(index_vreg));
li->addOperand(std::make_unique<ImmOperand>(const_index->getInt()));
CurMBB->addInstruction(std::move(li));
} else {
index_vreg = getVReg(indexValue);
}
if (stride == 1) {
auto mv = std::make_unique<MachineInstr>(RVOpcodes::MV);
mv->addOperand(std::make_unique<RegOperand>(offset_vreg));
mv->addOperand(std::make_unique<RegOperand>(index_vreg));
CurMBB->addInstruction(std::move(mv));
} else {
auto size_vreg = getNewVReg(Type::getIntType());
auto li_size = std::make_unique<MachineInstr>(RVOpcodes::LI);
li_size->addOperand(std::make_unique<RegOperand>(size_vreg));
li_size->addOperand(std::make_unique<ImmOperand>(stride));
CurMBB->addInstruction(std::move(li_size));
auto mul = std::make_unique<MachineInstr>(RVOpcodes::MULW);
mul->addOperand(std::make_unique<RegOperand>(offset_vreg));
mul->addOperand(std::make_unique<RegOperand>(index_vreg));
mul->addOperand(std::make_unique<RegOperand>(size_vreg));
CurMBB->addInstruction(std::move(mul));
}
// --- 关键修复点 ---
// 创建一个新的vreg来保存本次加法的结果。
unsigned current_step_addr_vreg = getNewVReg(gep->getType());
// 执行 add current_step, last_step, offset
// 这确保了 last_step_addr_vreg (输入) 永远不会被直接修改。
auto add = std::make_unique<MachineInstr>(RVOpcodes::ADD);
add->addOperand(std::make_unique<RegOperand>(current_step_addr_vreg));
add->addOperand(std::make_unique<RegOperand>(last_step_addr_vreg));
add->addOperand(std::make_unique<RegOperand>(offset_vreg));
CurMBB->addInstruction(std::move(add));
// 本次的结果成为下一次计算的输入。
last_step_addr_vreg = current_step_addr_vreg;
}
// --- 为下一次迭代更新类型 ---
if (auto array_type = current_type->as<ArrayType>()) {
current_type = array_type->getElementType();
} else if (auto ptr_type = current_type->as<PointerType>()) {
current_type = ptr_type->getBaseType();
}
}
// --- Step 3: 将最终计算出的地址存入GEP的目标虚拟寄存器 ---
auto final_mv = std::make_unique<MachineInstr>(RVOpcodes::MV);
final_mv->addOperand(std::make_unique<RegOperand>(result_vreg));
final_mv->addOperand(std::make_unique<RegOperand>(last_step_addr_vreg));
CurMBB->addInstruction(std::move(final_mv));
break;
}
}
default: