<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Apr 15, 2016 at 3:38 PM, Davide Italiano via llvm-commits <span dir="ltr"><<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: davide<br>
Date: Fri Apr 15 17:38:10 2016<br>
New Revision: 266484<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=266484&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=266484&view=rev</a><br>
Log:<br>
[LTO] Implement parallel Codegen for LTO using splitCodeGen.<br>
<br>
Parallelism level can be chosen using the new --lto-jobs=K option<br>
where K is the number of threads used for CodeGen. It currently<br>
defaults to 1.<br>
<br>
Added:<br>
lld/trunk/test/ELF/lto/parallel.ll<br>
Modified:<br>
lld/trunk/ELF/Config.h<br>
lld/trunk/ELF/Driver.cpp<br>
lld/trunk/ELF/LTO.cpp<br>
lld/trunk/ELF/LTO.h<br>
lld/trunk/ELF/Options.td<br>
lld/trunk/ELF/SymbolTable.cpp<br>
lld/trunk/test/ELF/basic.s<br>
<br>
Modified: lld/trunk/ELF/Config.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Config.h?rev=266484&r1=266483&r2=266484&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Config.h?rev=266484&r1=266483&r2=266484&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/Config.h (original)<br>
+++ lld/trunk/ELF/Config.h Fri Apr 15 17:38:10 2016<br>
@@ -94,6 +94,7 @@ struct Configuration {<br>
ELFKind EKind = ELFNoneKind;<br>
uint16_t EMachine = llvm::ELF::EM_NONE;<br>
uint64_t EntryAddr = -1;<br>
+ unsigned LtoJobs;<br>
unsigned LtoO;<br>
unsigned Optimize;<br>
};<br>
<br>
Modified: lld/trunk/ELF/Driver.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=266484&r1=266483&r2=266484&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=266484&r1=266483&r2=266484&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/Driver.cpp (original)<br>
+++ lld/trunk/ELF/Driver.cpp Fri Apr 15 17:38:10 2016<br>
@@ -321,6 +321,9 @@ void LinkerDriver::readConfigs(opt::Inpu<br>
Config->LtoO = getInteger(Args, OPT_lto_O, 2);<br>
if (Config->LtoO > 3)<br>
error("invalid optimization level for LTO: " + getString(Args, OPT_lto_O));<br>
+ Config->LtoJobs = getInteger(Args, OPT_lto_jobs, 1);<br>
+ if (Config->LtoJobs == 0)<br>
+ error("number of threads must be > 0");<br>
<br>
Config->ZExecStack = hasZOption(Args, "execstack");<br>
Config->ZNodelete = hasZOption(Args, "nodelete");<br>
<br>
Modified: lld/trunk/ELF/LTO.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.cpp?rev=266484&r1=266483&r2=266484&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.cpp?rev=266484&r1=266483&r2=266484&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/LTO.cpp (original)<br>
+++ lld/trunk/ELF/LTO.cpp Fri Apr 15 17:38:10 2016<br>
@@ -16,6 +16,7 @@<br>
#include "llvm/Analysis/TargetTransformInfo.h"<br>
#include "llvm/Bitcode/ReaderWriter.h"<br>
#include "llvm/CodeGen/CommandFlags.h"<br>
+#include "llvm/CodeGen/ParallelCG.h"<br>
#include "llvm/IR/LegacyPassManager.h"<br>
#include "llvm/Linker/IRMover.h"<br>
#include "llvm/Support/StringSaver.h"<br>
@@ -33,10 +34,13 @@ using namespace lld;<br>
using namespace lld::elf;<br>
<br>
// This is for use when debugging LTO.<br>
-static void saveLtoObjectFile(StringRef Buffer) {<br>
+static void saveLtoObjectFile(StringRef Buffer, unsigned I, bool Many) {<br>
+ SmallString<128> Filename = Config->OutputFile;<br>
+ if (Many)<br>
+ Filename += utostr(I);<br>
+ Filename += ".lto.o";<br>
std::error_code EC;<br>
- raw_fd_ostream OS(Config->OutputFile.str() + ".lto.o", EC,<br>
- sys::fs::OpenFlags::F_None);<br>
+ raw_fd_ostream OS(Filename, EC, sys::fs::OpenFlags::F_None);<br>
check(EC);<br>
OS << Buffer;<br>
}<br>
@@ -136,9 +140,36 @@ static void internalize(GlobalValue &GV)<br>
GV.setLinkage(GlobalValue::InternalLinkage);<br>
}<br>
<br>
+std::vector<std::unique_ptr<InputFile>> BitcodeCompiler::runSplitCodegen() {<br>
+ unsigned NumThreads = Config->LtoJobs;<br>
+ OwningData.resize(NumThreads);<br>
+<br>
+ std::list<raw_svector_ostream> OSs;<br>
+ std::vector<raw_pwrite_stream *> OSPtrs;<br></blockquote><div><br></div><div>Is there any reason you used std::list instead of std::vector? I think std::vector is generally preferred unless you really want to have a linked list.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
+ for (SmallString<0> &Obj : OwningData) {<br>
+ OSs.emplace_back(Obj);<br>
+ OSPtrs.push_back(&OSs.back());<br>
+ }<br>
+<br>
+ splitCodeGen(std::move(Combined), OSPtrs, {},<br>
+ [this]() { return getTargetMachine(); });<br>
+<br>
+ std::vector<std::unique_ptr<InputFile>> ObjFiles;<br>
+ for (SmallString<0> &Obj : OwningData)<br>
+ ObjFiles.push_back(createObjectFile(<br>
+ MemoryBufferRef(Obj, "LLD-INTERNAL-combined-lto-object")));<br>
+<br>
+ if (Config->SaveTemps)<br>
+ for (unsigned I = 0; I < NumThreads; ++I)<br>
+ saveLtoObjectFile(OwningData[I], I, NumThreads > 1);<br>
+<br>
+ return ObjFiles;<br>
+}<br>
+<br>
// Merge all the bitcode files we have seen, codegen the result<br>
// and return the resulting ObjectFile.<br>
-std::unique_ptr<InputFile> BitcodeCompiler::compile() {<br>
+std::vector<std::unique_ptr<InputFile>> BitcodeCompiler::compile() {<br>
+ TheTriple = Combined->getTargetTriple();<br>
for (const auto &Name : InternalizedSyms) {<br>
GlobalValue *GV = Combined->getNamedValue(Name.first());<br>
assert(GV);<br>
@@ -151,26 +182,16 @@ std::unique_ptr<InputFile> BitcodeCompil<br>
std::unique_ptr<TargetMachine> TM(getTargetMachine());<br>
runLTOPasses(*Combined, *TM);<br>
<br>
- raw_svector_ostream OS(OwningData);<br>
- legacy::PassManager CodeGenPasses;<br>
- if (TM->addPassesToEmitFile(CodeGenPasses, OS,<br>
- TargetMachine::CGFT_ObjectFile))<br>
- fatal("failed to setup codegen");<br>
- CodeGenPasses.run(*Combined);<br>
- MB = MemoryBuffer::getMemBuffer(OwningData,<br>
- "LLD-INTERNAL-combined-lto-object", false);<br>
- if (Config->SaveTemps)<br>
- saveLtoObjectFile(MB->getBuffer());<br>
- return createObjectFile(*MB);<br>
+ return runSplitCodegen();<br>
}<br>
<br>
-TargetMachine *BitcodeCompiler::getTargetMachine() {<br>
- StringRef TripleStr = Combined->getTargetTriple();<br>
+std::unique_ptr<TargetMachine> BitcodeCompiler::getTargetMachine() {<br>
std::string Msg;<br>
- const Target *T = TargetRegistry::lookupTarget(TripleStr, Msg);<br>
+ const Target *T = TargetRegistry::lookupTarget(TheTriple, Msg);<br>
if (!T)<br>
fatal("target not found: " + Msg);<br>
TargetOptions Options = InitTargetOptionsFromCodeGenFlags();<br>
Reloc::Model R = Config->Pic ? Reloc::PIC_ : Reloc::Static;<br>
- return T->createTargetMachine(TripleStr, "", "", Options, R);<br>
+ return std::unique_ptr<TargetMachine>(<br>
+ T->createTargetMachine(TheTriple, "", "", Options, R));<br>
}<br>
<br>
Modified: lld/trunk/ELF/LTO.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.h?rev=266484&r1=266483&r2=266484&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.h?rev=266484&r1=266483&r2=266484&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/LTO.h (original)<br>
+++ lld/trunk/ELF/LTO.h Fri Apr 15 17:38:10 2016<br>
@@ -37,20 +37,22 @@ class InputFile;<br>
class BitcodeCompiler {<br>
public:<br>
void add(BitcodeFile &F);<br>
- std::unique_ptr<InputFile> compile();<br>
+ std::vector<std::unique_ptr<InputFile>> compile();<br>
<br>
BitcodeCompiler()<br>
: Combined(new llvm::Module("ld-temp.o", Context)), Mover(*Combined) {}<br>
<br>
private:<br>
- llvm::TargetMachine *getTargetMachine();<br>
+ std::vector<std::unique_ptr<InputFile>> runSplitCodegen();<br>
+ std::unique_ptr<llvm::TargetMachine> getTargetMachine();<br>
<br>
llvm::LLVMContext Context;<br>
std::unique_ptr<llvm::Module> Combined;<br>
llvm::IRMover Mover;<br>
- SmallString<0> OwningData;<br>
+ std::vector<SmallString<0>> OwningData;<br>
std::unique_ptr<MemoryBuffer> MB;<br>
llvm::StringSet<> InternalizedSyms;<br>
+ std::string TheTriple;<br>
};<br>
}<br>
}<br>
<br>
Modified: lld/trunk/ELF/Options.td<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Options.td?rev=266484&r1=266483&r2=266484&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Options.td?rev=266484&r1=266483&r2=266484&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/Options.td (original)<br>
+++ lld/trunk/ELF/Options.td Fri Apr 15 17:38:10 2016<br>
@@ -237,7 +237,9 @@ def G : Separate<["-"], "G">;<br>
// Aliases for ignored options<br>
def alias_version_script_version_script : Joined<["--"], "version-script=">, Alias<version_script>;<br>
<br>
-// Debugging/developer options<br>
+// LTO-related options.<br>
+def lto_jobs : Joined<["--"], "lto-jobs=">,<br>
+ HelpText<"Number of threads to run codegen">;<br>
def disable_verify : Flag<["-"], "disable-verify">;<br>
def mllvm : Separate<["-"], "mllvm">;<br>
def save_temps : Flag<["-"], "save-temps">;<br>
<br>
Modified: lld/trunk/ELF/SymbolTable.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.cpp?rev=266484&r1=266483&r2=266484&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.cpp?rev=266484&r1=266483&r2=266484&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/SymbolTable.cpp (original)<br>
+++ lld/trunk/ELF/SymbolTable.cpp Fri Apr 15 17:38:10 2016<br>
@@ -122,24 +122,27 @@ template <class ELFT> void SymbolTable<E<br>
Lto.reset(new BitcodeCompiler);<br>
for (const std::unique_ptr<BitcodeFile> &F : BitcodeFiles)<br>
Lto->add(*F);<br>
- std::unique_ptr<InputFile> IF = Lto->compile();<br>
- ObjectFile<ELFT> *Obj = cast<ObjectFile<ELFT>>(IF.release());<br>
+ std::vector<std::unique_ptr<InputFile>> IFs = Lto->compile();<br>
<br>
// Replace bitcode symbols.<br>
- llvm::DenseSet<StringRef> DummyGroups;<br>
- Obj->parse(DummyGroups);<br>
- for (SymbolBody *Body : Obj->getNonLocalSymbols()) {<br>
- Symbol *Sym = insert(Body);<br>
- Sym->Body->setUsedInRegularObj();<br>
- if (Sym->Body->isShared())<br>
- Sym->Body->MustBeInDynSym = true;<br>
- if (Sym->Body->MustBeInDynSym)<br>
- Body->MustBeInDynSym = true;<br>
- if (!Sym->Body->isUndefined() && Body->isUndefined())<br>
- continue;<br>
- Sym->Body = Body;<br>
+ for (auto &IF : IFs) {<br>
+ ObjectFile<ELFT> *Obj = cast<ObjectFile<ELFT>>(IF.release());<br>
+<br>
+ llvm::DenseSet<StringRef> DummyGroups;<br>
+ Obj->parse(DummyGroups);<br>
+ for (SymbolBody *Body : Obj->getNonLocalSymbols()) {<br>
+ Symbol *Sym = insert(Body);<br>
+ Sym->Body->setUsedInRegularObj();<br>
+ if (Sym->Body->isShared())<br>
+ Sym->Body->MustBeInDynSym = true;<br>
+ if (Sym->Body->MustBeInDynSym)<br>
+ Body->MustBeInDynSym = true;<br>
+ if (!Sym->Body->isUndefined() && Body->isUndefined())<br>
+ continue;<br>
+ Sym->Body = Body;<br>
+ }<br>
+ ObjectFiles.emplace_back(Obj);<br>
}<br>
- ObjectFiles.emplace_back(Obj);<br>
}<br>
<br>
// Add an undefined symbol.<br>
<br>
Modified: lld/trunk/test/ELF/basic.s<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/basic.s?rev=266484&r1=266483&r2=266484&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/basic.s?rev=266484&r1=266483&r2=266484&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/test/ELF/basic.s (original)<br>
+++ lld/trunk/test/ELF/basic.s Fri Apr 15 17:38:10 2016<br>
@@ -214,3 +214,6 @@ _start:<br>
<br>
# RUN: not ld.lld %t -o %t -m wrong_emul 2>&1 | FileCheck --check-prefix=UNKNOWN_EMUL %s<br>
# UNKNOWN_EMUL: unknown emulation: wrong_emul<br>
+<br>
+# RUN: not ld.lld %t --lto-jobs=0 2>&1 | FileCheck --check-prefix=NOTHREADS %s<br>
+# NOTHREADS: number of threads must be > 0<br>
<br>
Added: lld/trunk/test/ELF/lto/parallel.ll<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/lto/parallel.ll?rev=266484&view=auto" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/lto/parallel.ll?rev=266484&view=auto</a><br>
==============================================================================<br>
--- lld/trunk/test/ELF/lto/parallel.ll (added)<br>
+++ lld/trunk/test/ELF/lto/parallel.ll Fri Apr 15 17:38:10 2016<br>
@@ -0,0 +1,22 @@<br>
+; RUN: llvm-as -o %t.bc %s<br>
+; RUN: ld.lld -m elf_x86_64 --lto-jobs=2 -save-temps -o %t %t.bc -shared<br>
+; RUN: llvm-nm %t0.lto.o | FileCheck --check-prefix=CHECK0 %s<br>
+; RUN: llvm-nm %t1.lto.o | FileCheck --check-prefix=CHECK1 %s<br>
+<br>
+target triple = "x86_64-unknown-linux-gnu"<br>
+<br>
+; CHECK0-NOT: bar<br>
+; CHECK0: T foo<br>
+; CHECK0-NOT: bar<br>
+define void @foo() {<br>
+ call void @bar()<br>
+ ret void<br>
+}<br>
+<br>
+; CHECK1-NOT: foo<br>
+; CHECK1: T bar<br>
+; CHECK1-NOT: foo<br>
+define void @bar() {<br>
+ call void @foo()<br>
+ ret void<br>
+}<br>
<br>
<br>
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</blockquote></div><br></div></div>