101 lines
4.5 KiB
C++
101 lines
4.5 KiB
C++
#pragma once
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#include "IR.h"
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#include "IRBuilder.h"
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#include "Pass.h"
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namespace sysy {
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// 优化前对SysY IR的预处理，也可以视作部分CFG优化
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// 主要包括删除无用指令、合并基本块、删除空块等
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// 这些操作可以在SysY IR生成时就完成，但为了简化IR生成过程，
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// 这里将其放在SysY IR生成后进行预处理
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// 同时兼容phi节点的处理，可以再mem2reg后再次调用优化
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//TODO: 可增加的CFG优化和方法
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// - 检查基本块跳转关系正确性
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// - 简化条件分支（Branch Simplification），如条件恒真/恒假转为直接跳转
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// - 合并连续的跳转指令（Jump Threading）在合并不可达块中似乎已经实现了
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// - 基本块重排序（Block Reordering），提升局部性
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// 辅助工具类，包含实际的CFG优化逻辑
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// 这些方法可以被独立的Pass调用
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class SysYCFGOptUtils {
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public:
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static bool SysYDelInstAfterBr(Function *func); // 删除br后面的指令
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static bool SysYDelEmptyBlock(Function *func, IRBuilder* pBuilder); // 空块删除
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static bool SysYDelNoPreBLock(Function *func); // 删除无前驱块（不可达块）
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static bool SysYBlockMerge(Function *func); // 合并基本块
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static bool SysYAddReturn(Function *func, IRBuilder* pBuilder); // 添加return指令
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static bool SysYCondBr2Br(Function *func, IRBuilder* pBuilder); // 条件分支转换为无条件分支
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};
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// ======================================================================
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// 独立的CFG优化遍
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// ======================================================================
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class SysYDelInstAfterBrPass : public OptimizationPass {
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public:
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static void *ID; // 唯一ID
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SysYDelInstAfterBrPass() : OptimizationPass("SysYDelInstAfterBrPass", Granularity::Function) {}
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bool runOnFunction(Function *F, AnalysisManager& AM) override;
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void getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const override {
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// 这个优化可能改变CFG结构，使一些CFG相关的分析失效
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// 可以在这里指定哪些分析会失效，例如支配树、活跃变量等
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// analysisInvalidations.insert(DominatorTreeAnalysisPass::ID); // 示例
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}
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void *getPassID() const override { return &ID; }
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};
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class SysYDelEmptyBlockPass : public OptimizationPass {
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private:
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IRBuilder *pBuilder;
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public:
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static void *ID;
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SysYDelEmptyBlockPass(IRBuilder *builder) : OptimizationPass("SysYDelEmptyBlockPass", Granularity::Function), pBuilder(builder) {}
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bool runOnFunction(Function *F, AnalysisManager& AM) override;
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void getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const override {};
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void *getPassID() const override { return &ID; }
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};
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class SysYDelNoPreBLockPass : public OptimizationPass {
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public:
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static void *ID;
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SysYDelNoPreBLockPass() : OptimizationPass("SysYDelNoPreBLockPass", Granularity::Function) {}
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bool runOnFunction(Function *F, AnalysisManager& AM) override;
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void getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const override {};
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void *getPassID() const override { return &ID; }
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};
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class SysYBlockMergePass : public OptimizationPass {
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public:
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static void *ID;
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SysYBlockMergePass() : OptimizationPass("SysYBlockMergePass", Granularity::Function) {}
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bool runOnFunction(Function *F, AnalysisManager& AM) override;
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void getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const override {};
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void *getPassID() const override { return &ID; }
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};
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class SysYAddReturnPass : public OptimizationPass {
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private:
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IRBuilder *pBuilder;
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public:
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static void *ID;
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SysYAddReturnPass(IRBuilder *builder) : OptimizationPass("SysYAddReturnPass", Granularity::Function), pBuilder(builder) {}
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bool runOnFunction(Function *F, AnalysisManager& AM) override;
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void getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const override {};
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void *getPassID() const override { return &ID; }
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};
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class SysYCondBr2BrPass : public OptimizationPass {
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private:
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IRBuilder *pBuilder;
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public:
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static void *ID;
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SysYCondBr2BrPass(IRBuilder *builder) : OptimizationPass("SysYCondBr2BrPass", Granularity::Function), pBuilder(builder) {}
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bool runOnFunction(Function *F, AnalysisManager& AM) override;
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void getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const override {};
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void *getPassID() const override { return &ID; }
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};
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} // namespace sysy
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