| Issue |
91381
|
| Summary |
How to pass arguments to a linking pass?
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
kdsjZh
|
## version of clang
clang 17.0.6 (from apt)
## Question
I'm working on a LTO pass, which have to be loaded on LTO. And I want to pass one argument to this LTO pass.
I tried to use mllvm, which previously works `clang -flto --ld-path=ld.lld -Wl,--load-pass-plugin=mypass.so -Wl,-mllvm,myarg1=argval test.c -o test`, but the lld report an error `-mllvm: ld.lld: Unknown command line argument xxx`.
What I want to know is how to give a myarg1 to the mypass.so, while lld is linking?
## Prior Discussion
I see two issues might be related, but fail to address my question.
In #56137, the folks suggest using ` -Xclang -load -Xclang lib.so ` and `-Xclang -fpass-plugin=lib.so`, which is loading the pass during compilation, while my case requires the pass work in the linking stage.
#63604, still, they need to give arguments for pass work in the compilation stage, while my scenario the pass is working in linking stage, which requires giving argument to the ld.lld.
## Reproduce
To test this issue, download and compile latest AFL++ (github.com/AFLplusplus/AFLplusplus), `NO_NYX=1 make source-only`, and use clang to test any simple program in the following command:
```
clang -flto --ld-path=ld.lld -Wl,--load-pass-plugin=SanitizerCoverageLTO.so -Wl,-mllvm,-lto-coverage-level=1 helloworld.c -o helloworld
```
Here the -lto-coverage-trace-pc is a `cl::opt` that can takes an interger as argument
```c
static cl::opt<int> ClCoverageLevel(
"lto-coverage-level",
cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
"3: all blocks and critical edges"),
cl::Hidden, cl::init(3));
```
What I want is using clang to achieve something similar to
```
opt -load-pass-plugin=./SanitizerCoverageLTO.so -lto-coverage-level=1 helloworld.o -o testhelloworld.o
```
Thanks!
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