llvm-project/lld/Common/Reproduce.cpp
Nico Weber 83e60f5a55 [lld/mac] Add --reproduce option
This adds support for ld.lld's --reproduce / lld-link's /reproduce:
flag to the MachO port. This flag can be added to a link command
to make the link write a tar file containing all inputs to the link
and a response file containing the link command. This can be used
to reproduce the link on another machine, which is useful for sharing
bug report inputs or performance test loads.

Since the linker is usually called through the clang driver and
adding linker flags can be a bit cumbersome, setting the env var
`LLD_REPRODUCE=foo.tar` triggers the feature as well.

The file response.txt in the archive can be used with
`ld64.lld.darwinnew $(cat response.txt)` as long as the contents are
smaller than the command-line limit, or with `ld64.lld.darwinnew
@response.txt` once D92149 is in.

The support in this patch is sufficient to create a tar file for
Chromium's base_unittests that can link after unpacking on a different
machine.

Differential Revision: https://reviews.llvm.org/D92274
2020-11-30 08:40:21 -05:00

67 lines
2.2 KiB
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//===- Reproduce.cpp - Utilities for creating reproducers -----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "lld/Common/Reproduce.h"
#include "llvm/Option/Arg.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
using namespace lld;
using namespace llvm;
using namespace llvm::sys;
// Makes a given pathname an absolute path first, and then remove
// beginning /. For example, "../foo.o" is converted to "home/john/foo.o",
// assuming that the current directory is "/home/john/bar".
// Returned string is a forward slash separated path even on Windows to avoid
// a mess with backslash-as-escape and backslash-as-path-separator.
std::string lld::relativeToRoot(StringRef path) {
SmallString<128> abs = path;
if (fs::make_absolute(abs))
return std::string(path);
path::remove_dots(abs, /*remove_dot_dot=*/true);
// This is Windows specific. root_name() returns a drive letter
// (e.g. "c:") or a UNC name (//net). We want to keep it as part
// of the result.
SmallString<128> res;
StringRef root = path::root_name(abs);
if (root.endswith(":"))
res = root.drop_back();
else if (root.startswith("//"))
res = root.substr(2);
path::append(res, path::relative_path(abs));
return path::convert_to_slash(res);
}
// Quote a given string if it contains a space character.
std::string lld::quote(StringRef s) {
if (s.contains(' '))
return ("\"" + s + "\"").str();
return std::string(s);
}
// Converts an Arg to a string representation suitable for a response file.
// To show an Arg in a diagnostic, use Arg::getAsString() instead.
std::string lld::toString(const opt::Arg &arg) {
std::string k = std::string(arg.getSpelling());
if (arg.getNumValues() == 0)
return k;
std::string v;
for (size_t i = 0; i < arg.getNumValues(); ++i) {
if (i > 0)
v.push_back(' ');
v += quote(arg.getValue(i));
}
if (arg.getOption().getRenderStyle() == opt::Option::RenderJoinedStyle)
return k + v;
return k + " " + v;
}