是否可以从Assembly文件中获取LLVM-IR? [英] Is it possible to get LLVM-IR from Assembly file?

问题描述

我使用命令编译了.S文件:

I compiled .S file using command:

clang-8 -c funcs.s -o funcs.o -emit-llvm

我发现，.o文件是以ELF格式生成的. 预计我会看到llvm-ir格式(结果文件开头带有"BC"字符).

I found, that .o file was generated in ELF format. I was expected to see llvm-ir format (with "BC" characters at the beginning of resulting file).

似乎，Clang忽略了"-emit-llvm"标志.

Seems, Clang ignores "-emit-llvm" flag.

推荐答案

您的问题与

Your question isn't fundamentally different from Is it possible to translate an assembly language to LLVM IR, optimize it and then recompile it to a different architecture?.

asm源文件和二进制可执行文件/目标文件基本上等效于此问题.您仍在尝试将其反编译为LLVM-IR.这很难，而且我不知道是否存在反编译器.

asm source and binary executables / object files are basically equivalent for this problem. You're still trying to decompile to LLVM-IR. This is hard, and I don't know if a decompiler exists.

似乎，Clang忽略了"-emit-llvm"标志.

Seems, Clang ignores "-emit-llvm" flag.

不，它只是不影响您要求它执行的操作中涉及的任何步骤.

No, it just didn't affect any of the steps involved in the operation you asked it to do.

您要求编译器将其编译为.o，所以就这样做了.

You asked your compiler to compile to a .o, so it did so.

如果输入是.c，而输出是.s，则它可以发出LLVM-IR，但是在这种情况下，LLVM-IR并不是组装.s的过程的一部分.到.o.

If the input had been .c and the output a .s, it would have been able to emit LLVM-IR, but in this case LLVM-IR wasn't part of the process of assembling a .s to a .o.

因此，当clang运行时，不存在该程序的LLVM-IR表示，因此没有任何内容可发送.

So no LLVM-IR representation of the program ever existed while clang was running, so there was nothing to emit.

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