[lld] r300089 - [coff] default to multiple parallel ThinLTO jobs

[Bob Haarman via llvm-commits]

Author: inglorion
Date: Wed Apr 12 13:36:13 2017
New Revision: 300089

URL: http://llvm.org/viewvc/llvm-project?rev=300089&view=rev
Log:
[coff] default to multiple parallel ThinLTO jobs

Summary:
lld-link allows the number of parallel ThinLTO jobs to be specified
using /opt:lldltojobs=N. If left unspecified, the implementation
conservatively defaults to 1. This leads to very long link times. This
change makes it so that the default is to automatically set the
parallelism, as we do in the ELF linker.

Reviewers: ruiu, hans

Reviewed By: ruiu, hans

Subscribers: pcc, mehdi_amini, Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D31986

Modified:
    lld/trunk/COFF/Config.h
    lld/trunk/COFF/LTO.cpp

Modified: lld/trunk/COFF/Config.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Config.h?rev=300089&r1=300088&r2=300089&view=diff
==============================================================================
--- lld/trunk/COFF/Config.h (original)
+++ lld/trunk/COFF/Config.h Wed Apr 12 13:36:13 2017
@@ -115,7 +115,7 @@ struct Configuration {
   unsigned LTOOptLevel = 2;
 
   // Used for /opt:lldltojobs=N
-  unsigned LTOJobs = 1;
+  unsigned LTOJobs = 0;
   // Used for /opt:lldltopartitions=N
   unsigned LTOPartitions = 1;
 

Modified: lld/trunk/COFF/LTO.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/LTO.cpp?rev=300089&r1=300088&r2=300089&view=diff
==============================================================================
--- lld/trunk/COFF/LTO.cpp (original)
+++ lld/trunk/COFF/LTO.cpp Wed Apr 12 13:36:13 2017
@@ -73,7 +73,7 @@ static std::unique_ptr<lto::LTO> createL
     checkError(Conf.addSaveTemps(std::string(Config->OutputFile) + ".",
                                  /*UseInputModulePath*/ true));
   lto::ThinBackend Backend;
-  if (Config->LTOJobs != -1u)
+  if (Config->LTOJobs != 0)
     Backend = lto::createInProcessThinBackend(Config->LTOJobs);
   return llvm::make_unique<lto::LTO>(std::move(Conf), Backend,
                                      Config->LTOPartitions);