[LTO] onfig::addSaveTemps: clear ResolutionFile upon an error

[MaskRay]

Summary

Otherwise ld.lld -save-temps will crash when writing to ResolutionFile.

llvm-lto2 -save-temps does not crash because it exits immediately.

[evgeny777]

LGTM

[hoyFB]

lld/test/ELF/lto/resolution-err.ll

6

The chmod is an issue when the test is run on a server without root access. Do you have an suggestion how to make it work? Thanks.

[MaskRay]

lld/test/ELF/lto/resolution-err.ll

6

Quote https://pubs.opengroup.org/onlinepubs/9699919799/utilities/chmod.html

Only a process whose effective user ID matches the user ID of the file, or a process with appropriate privileges, shall be permitted to change the file mode bits of a file.

The user ID of %t.resolution.txt is the current effective user ID. The current effective user ID can chmod -w the file. See llvm/test/tools/llvm-objcopy/ELF/mirror-permissions-unix.test for another example.

Is that not the case on your system?

[MaskRay]

lld/test/ELF/lto/resolution-err.ll

6

Or do you mean with root access?

This is so uncommon that I think maybe you should just disable the test internally.

[hoyFB]

lld/test/ELF/lto/resolution-err.ll

6

Thanks for the quick response! Let me take a deeper look into our file system. The test fails on our remote server with ld.lld run printing nothing which basically means the resolution file is either not created or is not write-protected.

lld/test/ELF/lto/resolution-err.ll

+; UNSUPPORTED: system-windows
+; REQUIRES: shell
+; RUN: llvm-as %s -o %t.bc
+; RUN: touch %t.resolution.txt
+; RUN: chmod -w %t.resolution.txt
+; RUN: not ld.lld -save-temps %t.bc -o %t 2>&1 | FileCheck %s
+; RUN: rm -f %t.resolution.txt
+
+; CHECK: error: {{[Pp]}}ermission denied{{$}}
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @_start() {
+  ret void
+}

llvm/lib/LTO/LTOBackend.cpp

 
 Error Config::addSaveTemps(std::string OutputFileName,
                            bool UseInputModulePath) {
   ShouldDiscardValueNames = false;
 
   std::error_code EC;
   ResolutionFile = std::make_unique<raw_fd_ostream>(
       OutputFileName + "resolution.txt", EC, sys::fs::OpenFlags::OF_Text);
-  if (EC)
+  if (EC) {
+    ResolutionFile.reset();
     return errorCodeToError(EC);
+  }
 
   auto setHook = [&](std::string PathSuffix, ModuleHookFn &Hook) {
     // Keep track of the hook provided by the linker, which also needs to run.
     ModuleHookFn LinkerHook = Hook;
     Hook = [=](unsigned Task, const Module &M) {
       // If the linker's hook returned false, we need to pass that result
       // through.
       if (LinkerHook && !LinkerHook(Task, M))