Gimli cannot parse multiple units in aarch64

[liutao-liu]

As shown in the following figure, when there are multiple units, Gimli parses only the first unit from the ELF file.

[philipc]

gimli definitely can parse multiple units, so you'll need to give more information on how to reproduce the problem you are seeing.

[philipc]

Can you provide an example file?

[liutao-liu]

My running environment: aarch64 + ubuntu 20.04 TSL Gimli version:0.28.1

The example in simple_line.rs attempt to parse all units in an object file. Then i run the example in simple_line.rs to parse my object. This object has two units, but simple_line.rs can only parse the first unit, as shown in the following figure.

My a.out comes out like this: test1.c

int func(){
    return 10;
}

test2.c

int main(int argc, char** argv)
{
  int ret = 1;
  return ret;
}

Compiling test1.c and test2.c using clang-16:

./clang+llvm-16.0.0-aarch64-linux-gnu/bin/clang -c -gdwarf-4 -emit-llvm test1.c -S -o test1.ll
./clang+llvm-16.0.0-aarch64-linux-gnu/bin/clang -c -gdwarf-4 -emit-llvm test2.c -S -o test2.ll
./clang+llvm-16.0.0-aarch64-linux-gnu/bin/llvm-link -o test.ll test1.ll test2.ll
./clang+llvm-16.0.0-aarch64-linux-gnu/bin/clang test.ll -c -o a.out

[philipc]

Please attach the binary a.out so that I can reproduce the issue.

[liutao-liu]

Sorry, I can't offer a.out. The example I've given is simple, and you can compile it very quickly by following the steps above. The problem can also be reproduced in the x86 environment.

[philipc]

It's simple to add the file to this issue, but okay, I'll have to wait until next week to look at it then.

[liutao-liu]

It's simple to add the file to this issue, but okay, I'll have to wait until next week to look at it then.

I don't have permission to upload files.

[philipc]

The problem is that you are building a relocatable object file, and the simple_line example does not process relocations, so various references in the DWARF are read as zeroes. If you build an executable then it works fine: clang test.ll -o a.out Alternatively, the dwarfdump example does process relocations.