llvm ir 没有按预期运行

Question

我有以下 llvm ir 并且花了一天中最好的时间尝试调试它我似乎无法处理它。当我的 windows 机器上运行时，该程序只是在循环中冻结（带有）段错误。

; standard declaration etc
%gen__list__0 = type { i8*, i64, i64 }
%const_array_offset = type { i64, i64 }
; other declaration etc
@gbl_constant_59 = common constant [20 x i8] c"aaaaaaaaaaaaaaaaaaaa", align 
; more function declarations etc

define internal %gen__list__0 @gen__fun__elevate12(%const_array_offset*) {
entry:
  %1 = alloca %gen__list__0
  %2 = getelementptr %const_array_offset, %const_array_offset* %0, i32 0, i32 0
  %3 = load i64, i64* %2
  %4 = getelementptr %const_array_offset, %const_array_offset* %0, i32 0, i32 1
  %5 = load i64, i64* %4
  %6 = sub i64 %5, %3
  %7 = mul i64 %6, i64 2
  %8 = getelementptr %gen__list__0, %gen__list__0* %1, i32 0, i32 0
  %9 = getelementptr %gen__list__0, %gen__list__0* %1, i32 0, i32 1
  %10 = getelementptr %gen__list__0, %gen__list__0* %1, i32 0, i32 2
  store i64 %6, i64* %9
  store i64 %7, i64* %10
  %11 = mul i64 ptrtoint (i8* getelementptr (i8, i8* null, i32 1) to i64), %7
  %12 = call i8* @malloc(i64 %11)
  store i8* %12, i8** %8
  %13 = getelementptr %gen__list__0, %gen__list__0* %1, i32 0, i32 0
  %14 = load i8*, i8** %13
  %15 = getelementptr i8, i8* %14, i64 %6
  %16 = getelementptr [20 x i8], [20 x i8]* @gbl_constant_59, i32 0, i64 %3
  %17 = alloca i8*
  store i8* %16, i8** %17
  %18 = alloca i8*
  store i8* %14, i8** %18
  br label %bb2

bb2:                                              ; preds = %bb3, %entry
  %19 = load i8*, i8** %18
  %20 = icmp ne i8* %19, %15
  br i1 %20, label %bb3, label %bb4

bb3:                                              ; preds = %bb2
  %21 = load i8*, i8** %17
  %22 = getelementptr i8, i8* %21, i32 1
  store i8* %22, i8** %17
  %23 = load i8*, i8** %18
  %24 = getelementptr i8, i8* %23, i32 1
  store i8* %24, i8** %18
  br label %bb2

bb4:                                              ; preds = %bb2
  %25 = load %gen__list__0, %gen__list__0* %1
  ret %gen__list__0 %25
}

感谢所有帮助纠正此问题 out/where it/I 可能出错了。

循环简单地实现了

c++ 风格的伪代码，用于实现这种循环

for(iterator it = begin; it != end; ++it) {
     //code in loop - atm blank
}

Answer 1

问题是通过llc放代码发现的。显然，标有公共链接的常量只能有一个零初始值设定项。要拥有一个没有零初始值设定项的全局常量，如此处 @gbl_constant_59 的情况，您需要声明该常量为内部或外部。

llvm ir 没有按预期运行

llvm ir not behaving as expected

compiler-construction

code-generation

llvm

llvm-ir