Lib.rs

• cargo-disassemble Easily disassemble your Rust project

** Usage cargo-disassemble attempts to emulate the command-line interface of other cargo subcommands. Notice that the function argument is optional - not including it will disassemble all functions in the current crate.

#+BEGIN_SRC text USAGE: cargo-disassemble [FLAGS] [OPTIONS] [function]

FLAGS: --all-features Enable all features --everything Include functions not defined by the current crate -h, --help Prints help information --intel Emit intel-flavored x86 ASM --no-default-features Enable no_default features --optimize Optimize the binary as much as possible --release Compile in release mode -V, --version Prints version information

OPTIONS: --features Features to enable, if any

ARGS: The name of the function to be decompiled #+END_SRC ** Example Given the function:

#+BEGIN_SRC rust #[inline(never)] fn is_branch_label(line: &str) -> bool { line.starts_with(".LBB") } #+END_SRC

we can disassemble the optimized version of is_branch_label with the following command:

#+BEGIN_SRC shell $ cargo disassemble is_branch_label --release --optimize --intel #+END_SRC

which will yield this result:

#+BEGIN_SRC asm cargo_disassemble::is_branch_label cmp rsi, 4 je .LBB66_4 cmp rsi, 5 jb .LBB66_3 cmp byte ptr [rdi + 4], -65 jle .LBB66_3 .LBB66_4: push rbp mov rbp, rsp sub rsp, 16 mov qword ptr [rbp - 16], rdi mov qword ptr [rbp - 8], rsi mov al, 1 lea rcx, [rip + .Lbyte_str.1e] cmp rdi, rcx lea rsp, [rsp + 16] pop rbp je .LBB66_6 cmp dword ptr [rdi], 1111641134 je .LBB66_6 .LBB66_3: xor eax, eax ret #+END_SRC ** Caveats When compiling in release mode, rustc will often aggressively inline smaller functions. Because inlined functions typically don't have a freestanding copy in the final binary, they may not be disassembled. Adding the #[inline(never)] attribute to a function will ensure it's included, but may also change the code within the function.