r282291 - [LTO] Add -flto-jobs=N to control backend parallelism
Teresa Johnson via cfe-commits
cfe-commits at lists.llvm.org
Fri Sep 23 13:38:09 PDT 2016
Author: tejohnson
Date: Fri Sep 23 15:38:09 2016
New Revision: 282291
URL: http://llvm.org/viewvc/llvm-project?rev=282291&view=rev
Log:
[LTO] Add -flto-jobs=N to control backend parallelism
Summary:
Currently, a linker option must be used to control the backend
parallelism of ThinLTO. The linker option varies depending on the
linker (e.g. gold vs ld64). Add a new clang option -flto-jobs=N
to control this.
I've added in the wiring to pass this to the gold plugin. I also
added in the logic to pass this down in the form I understand that
ld64 uses on MacOS, for the darwin target.
Reviewers: mehdi_amini, dexonsmith
Subscribers: mehdi_amini, cfe-commits
Differential Revision: https://reviews.llvm.org/D24826
Added:
cfe/trunk/test/Driver/lto-jobs.c
Modified:
cfe/trunk/include/clang/Driver/Options.td
cfe/trunk/lib/Driver/Tools.cpp
Modified: cfe/trunk/include/clang/Driver/Options.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=282291&r1=282290&r2=282291&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/Options.td (original)
+++ cfe/trunk/include/clang/Driver/Options.td Fri Sep 23 15:38:09 2016
@@ -812,6 +812,11 @@ def flto : Flag<["-"], "flto">, Flags<[C
HelpText<"Enable LTO in 'full' mode">;
def fno_lto : Flag<["-"], "fno-lto">, Group<f_Group>,
HelpText<"Disable LTO mode (default)">;
+def flto_jobs_EQ : Joined<["-"], "flto-jobs=">,
+ Flags<[CC1Option]>, Group<f_Group>,
+ HelpText<"Controls the backend parallelism of -flto=thin (default "
+ "of 0 means the number of threads will be derived from "
+ "the number of CPUs detected)">;
def fthinlto_index_EQ : Joined<["-"], "fthinlto-index=">,
Flags<[CC1Option]>, Group<f_Group>,
HelpText<"Perform ThinLTO importing using provided function summary index">;
Modified: cfe/trunk/lib/Driver/Tools.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=282291&r1=282290&r2=282291&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/Tools.cpp (original)
+++ cfe/trunk/lib/Driver/Tools.cpp Fri Sep 23 15:38:09 2016
@@ -1998,8 +1998,19 @@ static std::string getCPUName(const ArgL
}
}
+static unsigned getLTOParallelism(const ArgList &Args, const Driver &D) {
+ unsigned Parallelism = 0;
+ Arg *LtoJobsArg = Args.getLastArg(options::OPT_flto_jobs_EQ);
+ if (LtoJobsArg &&
+ StringRef(LtoJobsArg->getValue()).getAsInteger(10, Parallelism))
+ D.Diag(diag::err_drv_invalid_int_value) << LtoJobsArg->getAsString(Args)
+ << LtoJobsArg->getValue();
+ return Parallelism;
+}
+
static void AddGoldPlugin(const ToolChain &ToolChain, const ArgList &Args,
- ArgStringList &CmdArgs, bool IsThinLTO) {
+ ArgStringList &CmdArgs, bool IsThinLTO,
+ const Driver &D) {
// Tell the linker to load the plugin. This has to come before AddLinkerInputs
// as gold requires -plugin to come before any -plugin-opt that -Wl might
// forward.
@@ -2032,6 +2043,10 @@ static void AddGoldPlugin(const ToolChai
if (IsThinLTO)
CmdArgs.push_back("-plugin-opt=thinlto");
+ if (unsigned Parallelism = getLTOParallelism(Args, D))
+ CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=jobs=") +
+ std::to_string(Parallelism)));
+
// If an explicit debugger tuning argument appeared, pass it along.
if (Arg *A = Args.getLastArg(options::OPT_gTune_Group,
options::OPT_ggdbN_Group)) {
@@ -7639,7 +7654,7 @@ void cloudabi::Linker::ConstructJob(Comp
options::OPT_t, options::OPT_Z_Flag, options::OPT_r});
if (D.isUsingLTO())
- AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin);
+ AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin, D);
AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
@@ -8060,6 +8075,13 @@ void darwin::Linker::ConstructJob(Compil
getMachOToolChain().addProfileRTLibs(Args, CmdArgs);
+ if (unsigned Parallelism =
+ getLTOParallelism(Args, getToolChain().getDriver())) {
+ CmdArgs.push_back("-mllvm");
+ CmdArgs.push_back(
+ Args.MakeArgString(Twine("-threads=") + std::to_string(Parallelism)));
+ }
+
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (getToolChain().getDriver().CCCIsCXX())
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
@@ -8790,7 +8812,7 @@ void freebsd::Linker::ConstructJob(Compi
Args.AddAllArgs(CmdArgs, options::OPT_r);
if (D.isUsingLTO())
- AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin);
+ AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin, D);
bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
@@ -9623,7 +9645,7 @@ void gnutools::Linker::ConstructJob(Comp
ToolChain.AddFilePathLibArgs(Args, CmdArgs);
if (D.isUsingLTO())
- AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin);
+ AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin, D);
if (Args.hasArg(options::OPT_Z_Xlinker__no_demangle))
CmdArgs.push_back("--no-demangle");
Added: cfe/trunk/test/Driver/lto-jobs.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/lto-jobs.c?rev=282291&view=auto
==============================================================================
--- cfe/trunk/test/Driver/lto-jobs.c (added)
+++ cfe/trunk/test/Driver/lto-jobs.c Fri Sep 23 15:38:09 2016
@@ -0,0 +1,11 @@
+// Confirm that -flto-jobs=N is passed to linker
+
+// RUN: %clang -target x86_64-unknown-linux -### %s -flto=thin -flto-jobs=5 2> %t
+// RUN: FileCheck -check-prefix=CHECK-LINK-THIN-JOBS-ACTION < %t %s
+//
+// CHECK-LINK-THIN-JOBS-ACTION: "-plugin-opt=jobs=5"
+
+// RUN: %clang -target x86_64-apple-darwin13.3.0 -### %s -flto=thin -flto-jobs=5 2> %t
+// RUN: FileCheck -check-prefix=CHECK-LINK-THIN-JOBS2-ACTION < %t %s
+//
+// CHECK-LINK-THIN-JOBS2-ACTION: "-mllvm" "-threads=5"
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