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Fix NixOS patching #84071

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Merged
merged 1 commit into from
Apr 11, 2021
Merged

Fix NixOS patching #84071

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89 changes: 41 additions & 48 deletions src/bootstrap/bootstrap.py
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Original file line number Diff line number Diff line change
Expand Up @@ -429,7 +429,7 @@ def download_toolchain(self, stage0=True, rustc_channel=None):
lib_dir = "{}/lib".format(bin_root)
for lib in os.listdir(lib_dir):
if lib.endswith(".so"):
self.fix_bin_or_dylib(os.path.join(lib_dir, lib), rpath_libz=True)
self.fix_bin_or_dylib(os.path.join(lib_dir, lib))
with output(self.rustc_stamp(stage0)) as rust_stamp:
rust_stamp.write(key)

Expand Down Expand Up @@ -477,10 +477,10 @@ def download_toolchain(self, stage0=True, rustc_channel=None):
if self.program_out_of_date(self.llvm_stamp(), llvm_sha + str(llvm_assertions)):
self._download_ci_llvm(llvm_sha, llvm_assertions)
for binary in ["llvm-config", "FileCheck"]:
self.fix_bin_or_dylib(os.path.join(llvm_root, "bin", binary), rpath_libz=True)
self.fix_bin_or_dylib(os.path.join(llvm_root, "bin", binary))
for lib in os.listdir(llvm_lib):
if lib.endswith(".so"):
self.fix_bin_or_dylib(os.path.join(llvm_lib, lib), rpath_libz=True)
self.fix_bin_or_dylib(os.path.join(llvm_lib, lib))
with output(self.llvm_stamp()) as llvm_stamp:
llvm_stamp.write(llvm_sha + str(llvm_assertions))

Expand Down Expand Up @@ -548,7 +548,7 @@ def _download_ci_llvm(self, llvm_sha, llvm_assertions):
match="rust-dev",
verbose=self.verbose)

def fix_bin_or_dylib(self, fname, rpath_libz=False):
def fix_bin_or_dylib(self, fname):
"""Modifies the interpreter section of 'fname' to fix the dynamic linker,
or the RPATH section, to fix the dynamic library search path

Expand Down Expand Up @@ -583,56 +583,49 @@ def fix_bin_or_dylib(self, fname, rpath_libz=False):
# Only build `.nix-deps` once.
nix_deps_dir = self.nix_deps_dir
if not nix_deps_dir:
nix_deps_dir = ".nix-deps"
if not os.path.exists(nix_deps_dir):
os.makedirs(nix_deps_dir)

nix_deps = [
# Needed for the path of `ld-linux.so` (via `nix-support/dynamic-linker`).
"stdenv.cc.bintools",

# Needed as a system dependency of `libLLVM-*.so`.
"zlib",

# Needed for patching ELF binaries (see doc comment above).
"patchelf",
]

# Run `nix-build` to "build" each dependency (which will likely reuse
# the existing `/nix/store` copy, or at most download a pre-built copy).
# Importantly, we don't rely on `nix-build` printing the `/nix/store`
# path on stdout, but use `-o` to symlink it into `stage0/.nix-deps/$dep`,
# ensuring garbage collection will never remove the `/nix/store` path
# (which would break our patched binaries that hardcode those paths).
for dep in nix_deps:
try:
subprocess.check_output([
"nix-build", "<nixpkgs>",
"-A", dep,
"-o", "{}/{}".format(nix_deps_dir, dep),
])
except subprocess.CalledProcessError as reason:
print("warning: failed to call nix-build:", reason)
return

#
# Importantly, we create a gc-root called `.nix-deps` in the `build/`
# directory, but still reference the actual `/nix/store` path in the rpath
# as it makes it significantly more robust against changes to the location of
# the `.nix-deps` location.
#
# bintools: Needed for the path of `ld-linux.so` (via `nix-support/dynamic-linker`).
# zlib: Needed as a system dependency of `libLLVM-*.so`.
# patchelf: Needed for patching ELF binaries (see doc comment above).
nix_deps_dir = "{}/{}".format(self.build_dir, ".nix-deps")
nix_expr = '''
with (import <nixpkgs> {});
symlinkJoin {
name = "rust-stage0-dependencies";
paths = [
zlib
patchelf
stdenv.cc.bintools
];
}
'''
try:
subprocess.check_output([
"nix-build", "-E", nix_expr, "-o", nix_deps_dir,
])
except subprocess.CalledProcessError as reason:
print("warning: failed to call nix-build:", reason)
return
self.nix_deps_dir = nix_deps_dir

patchelf = "{}/patchelf/bin/patchelf".format(nix_deps_dir)
patchelf_args = []

if rpath_libz:
# Patch RPATH to add `zlib` dependency that stems from LLVM
dylib_deps = ["zlib"]
rpath_entries = [
# Relative default, all binary and dynamic libraries we ship
# appear to have this (even when `../lib` is redundant).
"$ORIGIN/../lib",
] + ["{}/{}/lib".format(nix_deps_dir, dep) for dep in dylib_deps]
patchelf_args += ["--set-rpath", ":".join(rpath_entries)]
patchelf = "{}/bin/patchelf".format(nix_deps_dir)
rpath_entries = [
# Relative default, all binary and dynamic libraries we ship
# appear to have this (even when `../lib` is redundant).
"$ORIGIN/../lib",
os.path.join(os.path.realpath(nix_deps_dir), "lib")
]
patchelf_args = ["--set-rpath", ":".join(rpath_entries)]
if not fname.endswith(".so"):
# Finally, set the corret .interp for binaries
bintools_dir = "{}/stdenv.cc.bintools".format(nix_deps_dir)
with open("{}/nix-support/dynamic-linker".format(bintools_dir)) as dynamic_linker:
with open("{}/nix-support/dynamic-linker".format(nix_deps_dir)) as dynamic_linker:
patchelf_args += ["--set-interpreter", dynamic_linker.read().rstrip()]

try:
Expand Down