52 lines
1.9 KiB
C++
52 lines
1.9 KiB
C++
#include "CalleeSavedHandler.h"
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#include <set>
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#include <vector>
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#include <algorithm>
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#include <iterator>
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namespace sysy {
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char CalleeSavedHandler::ID = 0;
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bool CalleeSavedHandler::runOnFunction(Function *F, AnalysisManager& AM) {
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// This pass works on MachineFunction level, not IR level
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return false;
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}
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void CalleeSavedHandler::runOnMachineFunction(MachineFunction* mfunc) {
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StackFrameInfo& frame_info = mfunc->getFrameInfo();
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const std::set<PhysicalReg>& used_callee_saved = frame_info.used_callee_saved_regs;
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if (used_callee_saved.empty()) {
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frame_info.callee_saved_size = 0;
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frame_info.callee_saved_regs_to_store.clear();
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return;
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}
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// 1. 计算被调用者保存寄存器所需的总空间大小
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// s0 总是由 PEI Pass 单独处理，这里不计入大小，但要确保它在列表中
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int size = 0;
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std::set<PhysicalReg> regs_to_save = used_callee_saved;
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if (regs_to_save.count(PhysicalReg::S0)) {
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regs_to_save.erase(PhysicalReg::S0);
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}
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size = regs_to_save.size() * 8; // 每个寄存器占8字节 (64-bit)
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frame_info.callee_saved_size = size;
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// 2. 创建一个有序的、需要保存的寄存器列表，以便后续 Pass 确定地生成代码
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// s0 不应包含在此列表中，因为它由 PEI Pass 特殊处理
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std::vector<PhysicalReg> sorted_regs(regs_to_save.begin(), regs_to_save.end());
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std::sort(sorted_regs.begin(), sorted_regs.end(), [](PhysicalReg a, PhysicalReg b){
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return static_cast<int>(a) < static_cast<int>(b);
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});
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frame_info.callee_saved_regs_to_store = sorted_regs;
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// 3. 更新栈帧总大小。
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// 这是初步计算，PEI Pass 会进行最终的对齐。
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frame_info.total_size = frame_info.locals_size +
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frame_info.spill_size +
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frame_info.callee_saved_size;
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}
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} // namespace sysy
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