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Workaround presence of LLVM library in stage0/lib

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This commit works around the newly-introduced LLVM shared library.

This is needed such that llvm-config run from
librustc_llvm's build script can correctly locate it's own LLVM, not the
one in stage0/lib. The LLVM build system uses the DT_RUNPATH/RUNPATH
header within the llvm-config binary, which we want to use, but because
Cargo always adds the host compiler's "libdir" (stage0/lib in our
case) to the dynamic linker's search path, we weren't properly finding
the freshly-built LLVM in llvm/lib. By restoring the environment
variable setting the search path to what bootstrap sees, the problem is
resolved and librustc_llvm correctly links and finds the appropriate
LLVM.

Several run-make-fulldeps tests are also updated with similar handling.
This commit is contained in:
Mark Rousskov 2019-01-21 17:47:57 -07:00
parent b7f030e114
commit 2d21df8a3f
11 changed files with 55 additions and 13 deletions
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9
src/bootstrap/builder.rs
View File

@ -21,7 +21,7 @@
use crate::native;
use crate::test;
use crate::tool;
use crate::util::{add_lib_path, exe, libdir};
use crate::util::{self, add_lib_path, exe, libdir};
use crate::{Build, DocTests, Mode, GitRepo};
pub use crate::Compiler;
@ -791,6 +791,13 @@ pub fn cargo(
.env("CARGO_TARGET_DIR", out_dir)
.arg(cmd);
// See comment in librustc_llvm/build.rs for why this is necessary, largely llvm-config
// needs to not accidentally link to libLLVM in stage0/lib.
cargo.env("REAL_LIBRARY_PATH_VAR", &util::dylib_path_var());
if let Some(e) = env::var_os(util::dylib_path_var()) {
cargo.env("REAL_LIBRARY_PATH", e);
}
if cmd != "install" {
cargo.arg("--target")
.arg(target);

1
src/bootstrap/compile.rs
View File

@ -712,6 +712,7 @@ pub fn build_codegen_backend(builder: &Builder,
if builder.is_rust_llvm(target) && backend != "emscripten" {
cargo.env("LLVM_RUSTLLVM", "1");
}
cargo.env("LLVM_CONFIG", &llvm_config);
if backend != "emscripten" {
let target_config = builder.config.target_config.get(&target);

6
src/bootstrap/util.rs
View File

@ -70,7 +70,11 @@ pub fn dylib_path_var() -> &'static str {
/// Parses the `dylib_path_var()` environment variable, returning a list of
/// paths that are members of this lookup path.
pub fn dylib_path() -> Vec<PathBuf> {
env::split_paths(&env::var_os(dylib_path_var()).unwrap_or_default()).collect()
let var = match env::var_os(dylib_path_var()) {
Some(v) => v,
None => return vec![],
};
env::split_paths(&var).collect()
}
/// `push` all components to `buf`. On windows, append `.exe` to the last component.

19
src/build_helper/lib.rs
View File

@ -23,6 +23,25 @@ macro_rules! t {
};
}
// Because Cargo adds the compiler's dylib path to our library search path, llvm-config may
// break: the dylib path for the compiler, as of this writing, contains a copy of the LLVM
// shared library, which means that when our freshly built llvm-config goes to load it's
// associated LLVM, it actually loads the compiler's LLVM. In particular when building the first
// compiler (i.e., in stage 0) that's a problem, as the compiler's LLVM is likely different from
// the one we want to use. As such, we restore the environment to what bootstrap saw. This isn't
// perfect -- we might actually want to see something from Cargo's added library paths -- but
// for now it works.
pub fn restore_library_path() {
println!("cargo:rerun-if-env-changed=REAL_LIBRARY_PATH_VAR");
println!("cargo:rerun-if-env-changed=REAL_LIBRARY_PATH");
let key = env::var_os("REAL_LIBRARY_PATH_VAR").expect("REAL_LIBRARY_PATH_VAR");
if let Some(env) = env::var_os("REAL_LIBRARY_PATH") {
env::set_var(&key, &env);
} else {
env::remove_var(&key);
}
}
pub fn run(cmd: &mut Command) {
println!("running: {:?}", cmd);
run_silent(cmd);

2
src/librustc_asan/build.rs
View File

@ -8,6 +8,8 @@
fn main() {
if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
build_helper::restore_library_path();
let (native, target) = match sanitizer_lib_boilerplate("asan") {
Ok(native) => native,
_ => return,

2
src/librustc_llvm/build.rs
View File

@ -24,6 +24,8 @@ fn main() {
return;
}
build_helper::restore_library_path();
let target = env::var("TARGET").expect("TARGET was not set");
let llvm_config = env::var_os("LLVM_CONFIG")
.map(PathBuf::from)

2
src/librustc_lsan/build.rs
View File

@ -8,6 +8,8 @@
fn main() {
if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
build_helper::restore_library_path();
let (native, target) = match sanitizer_lib_boilerplate("lsan") {
Ok(native) => native,
_ => return,

2
src/librustc_msan/build.rs
View File

@ -8,6 +8,8 @@
fn main() {
if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
build_helper::restore_library_path();
let (native, target) = match sanitizer_lib_boilerplate("msan") {
Ok(native) => native,
_ => return,

2
src/librustc_tsan/build.rs
View File

@ -8,6 +8,8 @@
fn main() {
if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
build_helper::restore_library_path();
let (native, target) = match sanitizer_lib_boilerplate("tsan") {
Ok(native) => native,
_ => return,

4
src/test/run-make-fulldeps/cross-lang-lto-upstream-rlibs/Makefile
View File

@ -9,7 +9,7 @@ all: staticlib.rs upstream.rs
# Check No LTO
$(RUSTC) staticlib.rs -Z cross-lang-lto -Ccodegen-units=1 -L. -o $(TMPDIR)/staticlib.a
(cd $(TMPDIR); llvm-ar x ./staticlib.a)
(cd $(TMPDIR); $(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-ar x ./staticlib.a)
# Make sure the upstream object file was included
ls $(TMPDIR)/upstream.*.rcgu.o
@ -19,5 +19,5 @@ all: staticlib.rs upstream.rs
# Check ThinLTO
$(RUSTC) upstream.rs -Z cross-lang-lto -Ccodegen-units=1 -Clto=thin
$(RUSTC) staticlib.rs -Z cross-lang-lto -Ccodegen-units=1 -Clto=thin -L. -o $(TMPDIR)/staticlib.a
(cd $(TMPDIR); llvm-ar x ./staticlib.a)
(cd $(TMPDIR); $(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-ar x ./staticlib.a)
ls $(TMPDIR)/upstream.*.rcgu.o

19
src/test/run-make-fulldeps/cross-lang-lto/Makefile
View File

@ -5,8 +5,9 @@
# LLVM bitcode files (as used by linker LTO plugins) when compiling with
# -Z cross-lang-lto.
ASSERT_IS_BITCODE_OBJ=llvm-bcanalyzer # this only succeeds for bitcode files
EXTRACT_OBJS=(cd $(TMPDIR); rm -f ./*.o; llvm-ar x $(1))
# this only succeeds for bitcode files
ASSERT_IS_BITCODE_OBJ=($(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-bcanalyzer $(1))
EXTRACT_OBJS=(cd $(TMPDIR); rm -f ./*.o; $(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-ar x $(1))
BUILD_LIB=$(RUSTC) lib.rs -Copt-level=2 -Z cross-lang-lto=on -Ccodegen-units=1
BUILD_EXE=$(RUSTC) main.rs -Copt-level=2 -Z cross-lang-lto=on -Ccodegen-units=1 --emit=obj
@ -16,31 +17,31 @@ all: staticlib staticlib-fat-lto staticlib-thin-lto rlib exe cdylib rdylib
staticlib: lib.rs
$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib.a
$(call EXTRACT_OBJS, liblib.a)
for file in $(TMPDIR)/liblib.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
for file in $(TMPDIR)/liblib.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
staticlib-fat-lto: lib.rs
$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib-fat-lto.a -Clto=fat
$(call EXTRACT_OBJS, liblib-fat-lto.a)
for file in $(TMPDIR)/liblib-fat-lto.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
for file in $(TMPDIR)/liblib-fat-lto.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
staticlib-thin-lto: lib.rs
$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib-thin-lto.a -Clto=thin
$(call EXTRACT_OBJS, liblib-thin-lto.a)
for file in $(TMPDIR)/liblib-thin-lto.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
for file in $(TMPDIR)/liblib-thin-lto.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
rlib: lib.rs
$(BUILD_LIB) --crate-type=rlib -o $(TMPDIR)/liblib.rlib
$(call EXTRACT_OBJS, liblib.rlib)
for file in $(TMPDIR)/liblib.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
for file in $(TMPDIR)/liblib.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
cdylib: lib.rs
$(BUILD_LIB) --crate-type=cdylib --emit=obj -o $(TMPDIR)/cdylib.o
$(ASSERT_IS_BITCODE_OBJ) $(TMPDIR)/cdylib.o
$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/cdylib.o)
rdylib: lib.rs
$(BUILD_LIB) --crate-type=dylib --emit=obj -o $(TMPDIR)/rdylib.o
$(ASSERT_IS_BITCODE_OBJ) $(TMPDIR)/rdylib.o
$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/rdylib.o)
exe: lib.rs
$(BUILD_EXE) -o $(TMPDIR)/exe.o
$(ASSERT_IS_BITCODE_OBJ) $(TMPDIR)/exe.o
$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/exe.o)