From fedb4b0a9f0540bc98f955c2d0d52a536ec4588c Mon Sep 17 00:00:00 2001
From: Lixuanwang <xlwmail@nudt.edu.cn>
Date: Fri, 18 Jul 2025 18:48:38 +0800
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---
 src/RISCv64Backend.cpp | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/RISCv64Backend.cpp b/src/RISCv64Backend.cpp
index 25012d4..22be499 100644
--- a/src/RISCv64Backend.cpp
+++ b/src/RISCv64Backend.cpp
@@ -1348,6 +1348,7 @@ RISCv64CodeGen::RegAllocResult RISCv64CodeGen::register_allocation(Function* fun
     int current_stack_offset = 0;
     std::set<AllocaInst*> allocas_in_func;
 
+    // 收集函数中的所有 AllocaInst
     for (const auto& bb_ptr : func->getBasicBlocks()) {
         for (const auto& inst_ptr : bb_ptr->getInstructions()) {
             if (auto alloca = dynamic_cast<AllocaInst*>(inst_ptr.get())) {
@@ -1356,10 +1357,28 @@ RISCv64CodeGen::RegAllocResult RISCv64CodeGen::register_allocation(Function* fun
         }
     }
 
+    // 为每个 AllocaInst 计算栈空间并分配偏移量
     for (auto alloca : allocas_in_func) {
-        int size = 4; // 假设 i32 或 float, 依旧是4字节
+        int total_size = 4; // 基本元素大小（int 或 float）
+        auto dims = alloca->getDims();
+        if (!dims.empty()) {
+            int num_elements = 1;
+            for (const auto& dim_use : dims) {
+                Value* dim_value = dim_use->getValue();
+                if (auto const_dim = dynamic_cast<ConstantValue*>(dim_value)) {
+                    if (const_dim->isInt()) {
+                        num_elements *= const_dim->getInt();
+                    } else {
+                        throw std::runtime_error("数组维度必须是整数");
+                    }
+                } else {
+                    throw std::runtime_error("数组维度必须是编译时常量");
+                }
+            }
+            total_size *= num_elements;
+        }
         alloc_result.stack_map[alloca] = current_stack_offset;
-        current_stack_offset += size;
+        current_stack_offset += total_size;
     }
     // RV64 修改: 为保存的 ra 和 s0 (各8字节) 预留16字节空间
     alloc_result.stack_size = current_stack_offset + 16;