From 3b1bafde9c11cd1f57a5043fd952799fc4766d3e Mon Sep 17 00:00:00 2001
From: rain2133 <1370973498@qq.com>
Date: Sun, 3 Aug 2025 13:45:13 +0800
Subject: [PATCH] =?UTF-8?q?[midend]=E5=B0=86alloca=E5=A3=B0=E6=98=8E?=
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---
 src/midend/Pass/Pass.cpp       |  4 ++++
 src/midend/SysYIRGenerator.cpp | 27 +++++++++++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/midend/Pass/Pass.cpp b/src/midend/Pass/Pass.cpp
index 3c91c00..5f74334 100644
--- a/src/midend/Pass/Pass.cpp
+++ b/src/midend/Pass/Pass.cpp
@@ -108,6 +108,10 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
         printPasses();
       }
 
+      this->clearPasses();
+      this->addPass(&DCE::ID); 
+      this->run();
+
       if (DEBUG) std::cout << "--- Custom optimization sequence finished ---\n";
     }
 
diff --git a/src/midend/SysYIRGenerator.cpp b/src/midend/SysYIRGenerator.cpp
index 16f9423..882c7db 100644
--- a/src/midend/SysYIRGenerator.cpp
+++ b/src/midend/SysYIRGenerator.cpp
@@ -586,7 +586,18 @@ std::any SysYIRGenerator::visitConstDecl(SysYParser::ConstDeclContext *ctx) {
 
     // 显式地为局部常量在栈上分配空间
     // alloca 的类型将是指针指向常量类型，例如 `int*` 或 `int[2][3]*`
+    // 将 alloca 全部集中到entry函数中
+    // 记录当前位置
+    BasicBlock *curBB = builder.getBasicBlock();
+    auto curPos =builder.getPosition();
+    Function *currentFunction = builder.getBasicBlock()->getParent();
+    BasicBlock *entryBB = currentFunction->getEntryBlock();
+    // 在terminator前插入
+    auto entryPos = entryBB->terminator();
+    builder.setPosition(entryBB, entryPos);
     AllocaInst *alloca = builder.createAllocaInst(Type::getPointerType(variableType), name);
+    // 恢复当前位置
+    builder.setPosition(curBB, curPos);
 
     ArrayValueTree *root = std::any_cast<ArrayValueTree *>(constDef->constInitVal()->accept(this));
     ValueCounter values;
@@ -743,8 +754,20 @@ std::any SysYIRGenerator::visitVarDecl(SysYParser::VarDeclContext *ctx) {
 
     // 对于数组，alloca 的类型将是指针指向数组类型，例如 `int[2][3]*`
     // 对于标量，alloca 的类型将是指针指向标量类型，例如 `int*`
-    AllocaInst* alloca =
-        builder.createAllocaInst(Type::getPointerType(variableType), name);
+
+    BasicBlock *curBB = builder.getBasicBlock();
+    auto curPos =builder.getPosition();
+    Function *currentFunction = builder.getBasicBlock()->getParent();
+    BasicBlock *entryBB = currentFunction->getEntryBlock();
+    // 在terminator前插入
+    auto entryPos = entryBB->terminator();
+    builder.setPosition(entryBB, entryPos);
+    AllocaInst *alloca = builder.createAllocaInst(Type::getPointerType(variableType), name);
+    // 恢复当前位置
+    builder.setPosition(curBB, curPos);
+
+    // AllocaInst* alloca =
+    //     builder.createAllocaInst(Type::getPointerType(variableType), name);
 
     if (varDef->initVal() != nullptr) {
       ValueCounter values;