Rollup merge of rust-lang#64166 - infinity0:master, r=alexcrichton

Better way of conditioning the sanitizer builds

Previously the build would take the presence of the LLVM_CONFIG envvar to
mean that the sanitizers should be built, but this is a common envvar that
could be set for reasons unrelated to the rustc sanitizers.

This commit adds a new envvar RUSTC_BUILD_SANITIZERS and uses it instead.

This PR or similar will be necessary in order to work correctly with rust-lang/compiler-builtins#296

src/bootstrap/compile.rs

@@ -212,6 +212,7 @@ pub fn std_cargo(builder: &Builder<'_>,
  emscripten: false,
  });
  cargo.env("LLVM_CONFIG", llvm_config);
+ cargo.env("RUSTC_BUILD_SANITIZERS", "1");
  }
 
  cargo.arg("--features").arg(features)

src/librustc_asan/build.rs

@@ -4,6 +4,9 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+ if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+ return;
+ }
  if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
  build_helper::restore_library_path();
 

src/librustc_lsan/build.rs

@@ -4,6 +4,9 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+ if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+ return;
+ }
  if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
  build_helper::restore_library_path();
 

src/librustc_msan/build.rs

@@ -4,6 +4,9 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+ if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+ return;
+ }
  if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
  build_helper::restore_library_path();
 

src/librustc_tsan/build.rs

@@ -4,6 +4,9 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+ if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+ return;
+ }
  if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
  build_helper::restore_library_path();