2 files changed, 67 insertions, 0 deletions
diff --git a/build/cargo-linker b/build/cargo-linker
new file mode 100755
index 0000000000..898e21d482
--- /dev/null
+++ b/build/cargo-linker
@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+
+# If you want to use a custom linker with Cargo, Cargo requires that you
+# specify it in Cargo.toml or via the matching environment variable.
+# Passing extra options to the linker is possible with Cargo via
+# RUSTFLAGS='-C link-args', but testing showed that doing this reliably
+# was difficult.
+#
+# Our solution to these problems is to use this wrapper script.  We pass
+# in the LD and the LDFLAGS to use via environment variables.
+#
+# * MOZ_CARGO_WRAP_LD is equivalent to CC on Unix-y platforms, and CC
+#   frequently has additional arguments in addition to the compiler
+#   itself.
+#
+# * MOZ_CARGO_WRAP_LDFLAGS contains space-separated arguments to pass,
+#   and not quoting it ensures that each of those arguments is passed
+#   as a separate argument to the actual LD.
+#
+# * In rare cases, we also need MOZ_CARGO_WRAP_LD_CXX, which is the
+#   equivalent of CXX, when linking C++ code. Usually, this should
+#   simply work by the use of CC and -lstdc++ (added by cc-rs).
+#   However, in the case of sanitizer runtimes, there is a separate
+#   runtime for C and C++ and linking C++ code with the C runtime can
+#   fail if the requested feature is in the C++ runtime only (bug 1747298).
+
+import os
+import sys
+
+# This is not necessarily run with a virtualenv python, so add
+# the necessary directory for the shellutil module.
+base_dir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
+sys.path.insert(0, os.path.join(base_dir, "python", "mozbuild"))
+from mozbuild.shellutil import split
+
+
+SANITIZERS = {
+    "asan": "address",
+    "hwasan": "hwaddress",
+    "lsan": "leak",
+    "msan": "memory",
+    "tsan": "thread",
+}
+
+use_clang_sanitizer = os.environ.get("MOZ_CLANG_NEWER_THAN_RUSTC_LLVM")
+wrap_ld = os.environ["MOZ_CARGO_WRAP_LD"]
+args = split(os.environ["MOZ_CARGO_WRAP_LDFLAGS"])
+for arg in sys.argv[1:]:
+    if arg in ["-lc++", "-lstdc++"]:
+        wrap_ld = os.environ["MOZ_CARGO_WRAP_LD_CXX"]
+    elif use_clang_sanitizer and arg.endswith("san.a"):
+        # When clang is newer than rustc's LLVM, we replace rust's sanitizer
+        # runtimes with clang's.
+        filename = os.path.basename(arg)
+        prefix, dot, suffix = filename[:-2].rpartition(".")
+        if (
+            prefix.startswith("librustc-")
+            and prefix.endswith("_rt") and dot == "."
+        ):
+            args.append(f"-fsanitize={SANITIZERS[suffix]}")
+            continue
+    args.append(arg)
+
+wrap_ld = split(wrap_ld)
+os.execvp(wrap_ld[0], wrap_ld + args)
diff --git a/build/cargo-linker.bat b/build/cargo-linker.bat
new file mode 100644
index 0000000000..36ab80dac3
--- /dev/null
+++ b/build/cargo-linker.bat
@@ -0,0 +1,2 @@
+@echo off
+%MOZ_CARGO_WRAP_LD% %MOZ_CARGO_WRAP_LDFLAGS% %*