[lld] r296702 - ELF: Add ThinLTO caching support.
Peter Collingbourne via llvm-commits
llvm-commits at lists.llvm.org
Wed Mar 1 18:36:33 PST 2017
On Wed, Mar 1, 2017 at 3:31 PM, Sean Silva <chisophugis at gmail.com> wrote:
>
>
> On Wed, Mar 1, 2017 at 3:00 PM, Peter Collingbourne via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: pcc
>> Date: Wed Mar 1 17:00:10 2017
>> New Revision: 296702
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=296702&view=rev
>> Log:
>> ELF: Add ThinLTO caching support.
>>
>> This patch adds an option named --thinlto-cache-dir, which specifies the
>> path to a directory in which to cache native object files for ThinLTO
>> incremental builds.
>>
>> Differential Revision: https://reviews.llvm.org/D30509
>>
>> Added:
>> lld/trunk/test/ELF/lto/Inputs/cache.ll
>> lld/trunk/test/ELF/lto/cache.ll
>> Modified:
>> lld/trunk/ELF/Config.h
>> lld/trunk/ELF/Driver.cpp
>> lld/trunk/ELF/LTO.cpp
>> lld/trunk/ELF/LTO.h
>> lld/trunk/ELF/Options.td
>>
>> Modified: lld/trunk/ELF/Config.h
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Config.h?
>> rev=296702&r1=296701&r2=296702&view=diff
>> ============================================================
>> ==================
>> --- lld/trunk/ELF/Config.h (original)
>> +++ lld/trunk/ELF/Config.h Wed Mar 1 17:00:10 2017
>> @@ -86,6 +86,7 @@ struct Configuration {
>> llvm::StringRef OptRemarksFilename;
>> llvm::StringRef SoName;
>> llvm::StringRef Sysroot;
>> + llvm::StringRef ThinLTOCacheDir;
>> std::string RPath;
>> std::vector<VersionDefinition> VersionDefinitions;
>> std::vector<llvm::StringRef> AuxiliaryList;
>>
>> Modified: lld/trunk/ELF/Driver.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp
>> ?rev=296702&r1=296701&r2=296702&view=diff
>> ============================================================
>> ==================
>> --- lld/trunk/ELF/Driver.cpp (original)
>> +++ lld/trunk/ELF/Driver.cpp Wed Mar 1 17:00:10 2017
>> @@ -583,6 +583,7 @@ void LinkerDriver::readConfigs(opt::Inpu
>> Config->Sysroot = getString(Args, OPT_sysroot);
>> Config->Target1Rel = getArg(Args, OPT_target1_rel, OPT_target1_abs,
>> false);
>> Config->Target2 = getTarget2(Args);
>> + Config->ThinLTOCacheDir = getString(Args, OPT_thinlto_cache_dir);
>> Config->ThinLTOJobs = getInteger(Args, OPT_thinlto_jobs, -1u);
>> Config->Threads = getArg(Args, OPT_threads, OPT_no_threads, true);
>> Config->Trace = Args.hasArg(OPT_trace);
>>
>> Modified: lld/trunk/ELF/LTO.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.cpp?re
>> v=296702&r1=296701&r2=296702&view=diff
>> ============================================================
>> ==================
>> --- lld/trunk/ELF/LTO.cpp (original)
>> +++ lld/trunk/ELF/LTO.cpp Wed Mar 1 17:00:10 2017
>> @@ -18,6 +18,7 @@
>> #include "llvm/ADT/StringRef.h"
>> #include "llvm/ADT/Twine.h"
>> #include "llvm/IR/DiagnosticPrinter.h"
>> +#include "llvm/LTO/Caching.h"
>> #include "llvm/LTO/Config.h"
>> #include "llvm/LTO/LTO.h"
>> #include "llvm/Object/SymbolicFile.h"
>> @@ -142,11 +143,24 @@ std::vector<InputFile *> BitcodeCompiler
>> std::vector<InputFile *> Ret;
>> unsigned MaxTasks = LTOObj->getMaxTasks();
>> Buff.resize(MaxTasks);
>> + Files.resize(MaxTasks);
>>
>> - checkError(LTOObj->run([&](size_t Task) {
>> - return llvm::make_unique<lto::NativeObjectStream>(
>> - llvm::make_unique<raw_svector_ostream>(Buff[Task]));
>> - }));
>> + // The --thinlto-cache-dir option specifies the path to a directory in
>> which
>> + // to cache native object files for ThinLTO incremental builds. If a
>> path was
>> + // specified, configure LTO to use it as the cache directory.
>> + lto::NativeObjectCache Cache;
>> + if (!Config->ThinLTOCacheDir.empty())
>> + Cache = lto::localCache(Config->ThinLTOCacheDir,
>> + [&](size_t Task, StringRef Path) {
>> + Files[Task] =
>> check(MemoryBuffer::getFile(Path));
>> + });
>> +
>> + checkError(LTOObj->run(
>> + [&](size_t Task) {
>> + return llvm::make_unique<lto::NativeObjectStream>(
>> + llvm::make_unique<raw_svector_ostream>(Buff[Task]));
>> + },
>> + Cache));
>>
>> for (unsigned I = 0; I != MaxTasks; ++I) {
>> if (Buff[I].empty())
>> @@ -160,5 +174,10 @@ std::vector<InputFile *> BitcodeCompiler
>> InputFile *Obj = createObjectFile(MemoryBufferRef(Buff[I],
>> "lto.tmp"));
>> Ret.push_back(Obj);
>> }
>> +
>> + for (std::unique_ptr<MemoryBuffer> &File : Files)
>> + if (File)
>> + Ret.push_back(createObjectFile(*File));
>> +
>> return Ret;
>> }
>>
>> Modified: lld/trunk/ELF/LTO.h
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.h?rev=
>> 296702&r1=296701&r2=296702&view=diff
>> ============================================================
>> ==================
>> --- lld/trunk/ELF/LTO.h (original)
>> +++ lld/trunk/ELF/LTO.h Wed Mar 1 17:00:10 2017
>> @@ -49,6 +49,7 @@ public:
>> private:
>> std::unique_ptr<llvm::lto::LTO> LTOObj;
>> std::vector<SmallString<0>> Buff;
>> + std::vector<std::unique_ptr<MemoryBuffer>> Files;
>> };
>> }
>> }
>>
>> Modified: lld/trunk/ELF/Options.td
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Options.td
>> ?rev=296702&r1=296701&r2=296702&view=diff
>> ============================================================
>> ==================
>> --- lld/trunk/ELF/Options.td (original)
>> +++ lld/trunk/ELF/Options.td Wed Mar 1 17:00:10 2017
>> @@ -392,4 +392,6 @@ def opt_remarks_filename: S<"opt-remarks
>> def opt_remarks_with_hotness: F<"opt-remarks-with-hotness">,
>> HelpText<"Include hotness informations in the optimization remarks
>> file">;
>> def save_temps: F<"save-temps">;
>> +def thinlto_cache_dir: J<"thinlto-cache-dir=">,
>> + HelpText<"Path to ThinLTO cached object file directory">;
>> def thinlto_jobs: J<"thinlto-jobs=">, HelpText<"Number of ThinLTO jobs">;
>>
>> Added: lld/trunk/test/ELF/lto/Inputs/cache.ll
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/lto/
>> Inputs/cache.ll?rev=296702&view=auto
>> ============================================================
>> ==================
>> --- lld/trunk/test/ELF/lto/Inputs/cache.ll (added)
>> +++ lld/trunk/test/ELF/lto/Inputs/cache.ll Wed Mar 1 17:00:10 2017
>> @@ -0,0 +1,10 @@
>> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>> +target triple = "x86_64-unknown-linux-gnu"
>> +
>> +define i32 @main() {
>> +entry:
>> + call void (...) @globalfunc()
>> + ret i32 0
>> +}
>> +
>> +declare void @globalfunc(...)
>>
>> Added: lld/trunk/test/ELF/lto/cache.ll
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/lto/
>> cache.ll?rev=296702&view=auto
>> ============================================================
>> ==================
>> --- lld/trunk/test/ELF/lto/cache.ll (added)
>> +++ lld/trunk/test/ELF/lto/cache.ll Wed Mar 1 17:00:10 2017
>> @@ -0,0 +1,15 @@
>> +; RUN: opt -module-hash -module-summary %s -o %t.o
>> +; RUN: opt -module-hash -module-summary %p/Inputs/cache.ll -o %t2.o
>> +
>> +; RUN: rm -Rf %t.cache && mkdir %t.cache
>> +; RUN: ld.lld --thinlto-cache-dir=%t.cache -o %t3.o %t2.o %t.o
>>
>
> I find this a bit confusing. The argument to `-o` is a .o file, but -r is
> not passed.
>
Renamed to %t3 in r296728.
> Also, there doesn't seem to be a definition of _start in any of the input
> files?
>
I believe that we will accept an undefined entry symbol in executables with
a warning (that is what bfd and gold do). I don't know how important it is
to accept that, though. Rui, Rafael?
For now I've renamed the main symbol to _start.
Thanks,
--
--
Peter
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