[midend-BuildCFG]新增BuildCFG优化通道，实现控制流图的构建与分析

src/include/midend/Pass/Optimize/BuildCFG.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include "Pass.h"
+#include "IR.h"
+#include "Instruction.h"
+#include <queue>
+#include <set>
+
+namespace sysy {
+
+class DominatorTreeAnalysisPass;
+class LivenessAnalysisPass;
+
+class BuildCFG : public OptimizationPass {
+public:
+    // Pass的唯一ID，用于PassRegistry
+    static char ID;
+
+    BuildCFG() : OptimizationPass("BuildCFG", Pass::Granularity::Function, Pass::PassKind::Optimization) {}
+
+    // 重载 runOnFunction 方法，实现具体的优化逻辑
+    bool runOnFunction(Function *F, AnalysisManager& AM) override;
+
+    // 提供PassID
+    void *getPassID() const override { return &ID; }
+
+    // 声明Pass的分析使用
+    // BuildCFG不依赖任何分析，但会使其他依赖CFG的分析失效
+    void getAnalysisUsage(std::set<void *> &analysisDependencies,
+                          std::set<void *> &analysisInvalidations) override;
+};
+
+} // namespace sysy