diff options
Diffstat (limited to 'src/bootstrap/bin')
| -rw-r--r-- | src/bootstrap/bin/rustc.rs | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs index ca86aeb8100..28c8a75a13a 100644 --- a/src/bootstrap/bin/rustc.rs +++ b/src/bootstrap/bin/rustc.rs @@ -181,6 +181,33 @@ fn main() { cmd.arg("-C").arg(format!("debug-assertions={}", debug_assertions)); } + // Build all crates in the `std` facade with `-Z emit-stack-sizes` to add stack usage + // information. + // + // When you use this `-Z` flag with Cargo you get stack usage information on all crates + // compiled from source, and when you are using LTO you also get information on pre-compiled + // crates like `core` and `std`, even if they were not compiled with `-Z emit-stack-sizes`. + // However, there's an exception: `compiler_builtins`. This crate is special and doesn't + // participate in LTO because it's always linked as a separate object file. For this reason + // it's impossible to get stack usage information about `compiler-builtins` using + // `RUSTFLAGS` + Cargo, or `cargo rustc`. + // + // To make the stack usage information of all crates under the `std` facade available to + // Cargo based stack usage analysis tools, in both LTO and non-LTO mode, we compile them + // with the `-Z emit-stack-sizes` flag. The `RUSTC_EMIT_STACK_SIZES` var helps us apply this + // flag only to the crates in the `std` facade. The `-Z` flag is known to currently work + // with targets that produce ELF files so we limit its use flag to those targets. + // + // NOTE(japaric) if this ever causes problem with an LLVM upgrade or any PR feel free to + // remove it or comment it out + if env::var_os("RUSTC_EMIT_STACK_SIZES").is_some() + && (target.contains("-linux-") + || target.contains("-none-eabi") + || target.ends_with("-none-elf")) + { + cmd.arg("-Zemit-stack-sizes"); + } + if let Ok(s) = env::var("RUSTC_CODEGEN_UNITS") { cmd.arg("-C").arg(format!("codegen-units={}", s)); } |