diff options
| -rw-r--r-- | src/bootstrap/src/core/build_steps/compile.rs | 29 | ||||
| -rw-r--r-- | src/bootstrap/src/core/builder/tests.rs | 8 |
2 files changed, 19 insertions, 18 deletions
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs index 09bb2e35bda..9d29b1320b1 100644 --- a/src/bootstrap/src/core/build_steps/compile.rs +++ b/src/bootstrap/src/core/build_steps/compile.rs @@ -1323,7 +1323,7 @@ pub fn rustc_cargo_env( builder: &Builder<'_>, cargo: &mut Cargo, target: TargetSelection, - build_stage: u32, + _build_stage: u32, ) { // Set some configuration variables picked up by build scripts and // the compiler alike @@ -1379,18 +1379,24 @@ pub fn rustc_cargo_env( cargo.rustflag("--cfg=llvm_enzyme"); } - // Note that this is disabled if LLVM itself is disabled or we're in a check - // build. If we are in a check build we still go ahead here presuming we've - // detected that LLVM is already built and good to go which helps prevent - // busting caches (e.g. like #71152). + // These conditionals represent a tension between three forces: + // - For non-check builds, we need to define some LLVM-related environment + // variables, requiring LLVM to have been built. + // - For check builds, we want to avoid building LLVM if possible. + // - Check builds and non-check builds should have the same environment if + // possible, to avoid unnecessary rebuilds due to cache-busting. + // + // Therefore we try to avoid building LLVM for check builds, but only if + // building LLVM would be expensive. If "building" LLVM is cheap + // (i.e. it's already built or is downloadable), we prefer to maintain a + // consistent environment between check and non-check builds. if builder.config.llvm_enabled(target) { - let building_is_expensive = + let building_llvm_is_expensive = crate::core::build_steps::llvm::prebuilt_llvm_config(builder, target, false) .should_build(); - // `top_stage == stage` might be false for `check --stage 1`, if we are building the stage 1 compiler - let can_skip_build = builder.kind == Kind::Check && builder.top_stage == build_stage; - let should_skip_build = building_is_expensive && can_skip_build; - if !should_skip_build { + + let skip_llvm = (builder.kind == Kind::Check) && building_llvm_is_expensive; + if !skip_llvm { rustc_llvm_env(builder, cargo, target) } } @@ -1407,6 +1413,9 @@ pub fn rustc_cargo_env( /// Pass down configuration from the LLVM build into the build of /// rustc_llvm and rustc_codegen_llvm. +/// +/// Note that this has the side-effect of _building LLVM_, which is sometimes +/// unwanted (e.g. for check builds). fn rustc_llvm_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetSelection) { if builder.config.is_rust_llvm(target) { cargo.env("LLVM_RUSTLLVM", "1"); diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs index e71edbb8bc5..97e7e512ce1 100644 --- a/src/bootstrap/src/core/builder/tests.rs +++ b/src/bootstrap/src/core/builder/tests.rs @@ -1298,7 +1298,6 @@ mod snapshot { ctx.config("check") .path("compiler") .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> [check] rustc 0 <host> -> cranelift 1 <host> [check] rustc 0 <host> -> gcc 1 <host> @@ -1312,7 +1311,6 @@ mod snapshot { ctx.config("check") .path("rustc") .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> "); } @@ -1332,7 +1330,6 @@ mod snapshot { .path("compiler") .stage(1) .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> [check] rustc 0 <host> -> cranelift 1 <host> [check] rustc 0 <host> -> gcc 1 <host> @@ -1464,7 +1461,6 @@ mod snapshot { .paths(&["library", "compiler"]) .args(&args) .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> [check] rustc 0 <host> -> cranelift 1 <host> [check] rustc 0 <host> -> gcc 1 <host> @@ -1478,7 +1474,6 @@ mod snapshot { ctx.config("check") .path("miri") .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> [check] rustc 0 <host> -> Miri 1 <host> "); @@ -1499,7 +1494,6 @@ mod snapshot { .path("miri") .stage(1) .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> [check] rustc 0 <host> -> Miri 1 <host> "); @@ -1552,7 +1546,6 @@ mod snapshot { ctx.config("check") .path("rustc_codegen_cranelift") .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> [check] rustc 0 <host> -> cranelift 1 <host> [check] rustc 0 <host> -> gcc 1 <host> @@ -1566,7 +1559,6 @@ mod snapshot { ctx.config("check") .path("rust-analyzer") .render_steps(), @r" - [build] llvm <host> [check] rustc 0 <host> -> rustc 1 <host> [check] rustc 0 <host> -> rust-analyzer 1 <host> "); |