Export ZERO_AR_DATE for macos linker invocations

This commit attempts to improve reproducibility of builds on macOS by
exporting the `ZERO_AR_DATE=1` environment variable for all invocations
of the linker. While it looks like this env var is targeted at just the
`ar` command (which does actually read this) it appears that recent-ish
versions of the linker *also* read this environment variable. This
env var forces the linker to set a deterministic zero value for the
mtime in the N_OSO field of the object file.

Currently it's believe that older versions of the linker will simply
ignore this env var, while newer versions will read it and produce a
deterministic output for compilations with debuginfo.

Closes #47086
Closes #66568
This commit is contained in:
Alex Crichton 2020-05-05 14:25:58 -07:00
parent cb272d5d21
commit afd88f2a33
2 changed files with 12 additions and 2 deletions

View file

@ -2,7 +2,6 @@
# ignore-musl
# ignore-windows
# ignore-macos (rust-lang/rust#66568)
# Objects are reproducible but their path is not.
all: \
@ -21,7 +20,7 @@ sysroot:
rm -rf $(TMPDIR) && mkdir $(TMPDIR)
$(RUSTC) reproducible-build-aux.rs
$(RUSTC) reproducible-build.rs --crate-type rlib --sysroot $(shell $(RUSTC) --print sysroot) --remap-path-prefix=$(shell $(RUSTC) --print sysroot)=/sysroot
cp -r $(shell $(RUSTC) --print sysroot) $(TMPDIR)/sysroot
cp -R $(shell $(RUSTC) --print sysroot) $(TMPDIR)/sysroot
cp $(TMPDIR)/libreproducible_build.rlib $(TMPDIR)/libfoo.rlib
$(RUSTC) reproducible-build.rs --crate-type rlib --sysroot $(TMPDIR)/sysroot --remap-path-prefix=$(TMPDIR)/sysroot=/sysroot
cmp "$(TMPDIR)/libreproducible_build.rlib" "$(TMPDIR)/libfoo.rlib" || exit 1