r350949 - [LTO] Add option to enable LTOUnit splitting, and disable unless needed
Teresa Johnson via cfe-commits
cfe-commits at lists.llvm.org
Fri Jan 11 10:32:08 PST 2019
Author: tejohnson
Date: Fri Jan 11 10:32:07 2019
New Revision: 350949
URL: http://llvm.org/viewvc/llvm-project?rev=350949&view=rev
Log:
[LTO] Add option to enable LTOUnit splitting, and disable unless needed
Summary:
Adds a new -f[no]split-lto-unit flag that is disabled by default to
control module splitting during ThinLTO. It is automatically enabled
for -fsanitize=cfi and -fwhole-program-vtables.
The new EnableSplitLTOUnit codegen flag is passed down to llvm
via a new module flag of the same name.
Depends on D53890.
Reviewers: pcc
Subscribers: ormris, mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D53891
Added:
cfe/trunk/test/Driver/split-lto-unit.c
Modified:
cfe/trunk/include/clang/Basic/CodeGenOptions.def
cfe/trunk/include/clang/Driver/Options.td
cfe/trunk/include/clang/Driver/SanitizerArgs.h
cfe/trunk/lib/CodeGen/BackendUtil.cpp
cfe/trunk/lib/Driver/SanitizerArgs.cpp
cfe/trunk/lib/Driver/ToolChains/Clang.cpp
cfe/trunk/lib/Frontend/CompilerInvocation.cpp
cfe/trunk/test/CodeGen/thinlto-distributed-cfi-devirt.ll
cfe/trunk/test/CodeGen/thinlto-distributed-cfi.ll
cfe/trunk/test/CodeGenCXX/no-lto-unit.cpp
cfe/trunk/test/CodeGenCXX/type-metadata-thinlto.cpp
Modified: cfe/trunk/include/clang/Basic/CodeGenOptions.def
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/CodeGenOptions.def?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/CodeGenOptions.def (original)
+++ cfe/trunk/include/clang/Basic/CodeGenOptions.def Fri Jan 11 10:32:07 2019
@@ -116,6 +116,10 @@ CODEGENOPT(PrepareForThinLTO , 1, 0) ///
///< compile step.
CODEGENOPT(LTOUnit, 1, 0) ///< Emit IR to support LTO unit features (CFI, whole
///< program vtable opt).
+CODEGENOPT(EnableSplitLTOUnit, 1, 0) ///< Enable LTO unit splitting to support
+ /// CFI and traditional whole program
+ /// devirtualization that require whole
+ /// program IR support.
CODEGENOPT(IncrementalLinkerCompatible, 1, 0) ///< Emit an object file which can
///< be used with an incremental
///< linker.
Modified: cfe/trunk/include/clang/Driver/Options.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/Options.td (original)
+++ cfe/trunk/include/clang/Driver/Options.td Fri Jan 11 10:32:07 2019
@@ -1776,6 +1776,11 @@ def fwhole_program_vtables : Flag<["-"],
HelpText<"Enables whole-program vtable optimization. Requires -flto">;
def fno_whole_program_vtables : Flag<["-"], "fno-whole-program-vtables">, Group<f_Group>,
Flags<[CoreOption]>;
+def fsplit_lto_unit : Flag<["-"], "fsplit-lto-unit">, Group<f_Group>,
+ Flags<[CoreOption, CC1Option]>,
+ HelpText<"Enables splitting of the LTO unit.">;
+def fno_split_lto_unit : Flag<["-"], "fno-split-lto-unit">, Group<f_Group>,
+ Flags<[CoreOption]>;
def fforce_emit_vtables : Flag<["-"], "fforce-emit-vtables">, Group<f_Group>,
Flags<[CC1Option]>,
HelpText<"Emits more virtual tables to improve devirtualization">;
Modified: cfe/trunk/include/clang/Driver/SanitizerArgs.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/SanitizerArgs.h?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/SanitizerArgs.h (original)
+++ cfe/trunk/include/clang/Driver/SanitizerArgs.h Fri Jan 11 10:32:07 2019
@@ -81,6 +81,7 @@ class SanitizerArgs {
bool requiresPIE() const;
bool needsUnwindTables() const;
+ bool needsLTO() const;
bool linkCXXRuntimes() const { return LinkCXXRuntimes; }
bool hasCrossDsoCfi() const { return CfiCrossDso; }
bool hasAnySanitizer() const { return !Sanitizers.empty(); }
Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/BackendUtil.cpp?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/BackendUtil.cpp (original)
+++ cfe/trunk/lib/CodeGen/BackendUtil.cpp Fri Jan 11 10:32:07 2019
@@ -814,6 +814,8 @@ void EmitAssemblyHelper::EmitAssembly(Ba
if (!ThinLinkOS)
return;
}
+ TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
+ CodeGenOpts.EnableSplitLTOUnit);
PerModulePasses.add(createWriteThinLTOBitcodePass(
*OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
} else {
@@ -824,12 +826,15 @@ void EmitAssemblyHelper::EmitAssembly(Ba
!CodeGenOpts.DisableLLVMPasses &&
llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
llvm::Triple::Apple);
- if (EmitLTOSummary && !TheModule->getModuleFlag("ThinLTO"))
- TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
+ if (EmitLTOSummary) {
+ if (!TheModule->getModuleFlag("ThinLTO"))
+ TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
+ TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
+ CodeGenOpts.EnableSplitLTOUnit);
+ }
- PerModulePasses.add(
- createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
- EmitLTOSummary));
+ PerModulePasses.add(createBitcodeWriterPass(
+ *OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
}
break;
@@ -1054,6 +1059,8 @@ void EmitAssemblyHelper::EmitAssemblyWit
if (!ThinLinkOS)
return;
}
+ TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
+ CodeGenOpts.EnableSplitLTOUnit);
MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
: nullptr));
} else {
@@ -1064,11 +1071,14 @@ void EmitAssemblyHelper::EmitAssemblyWit
!CodeGenOpts.DisableLLVMPasses &&
llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
llvm::Triple::Apple);
- if (EmitLTOSummary && !TheModule->getModuleFlag("ThinLTO"))
- TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
-
- MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
- EmitLTOSummary));
+ if (EmitLTOSummary) {
+ if (!TheModule->getModuleFlag("ThinLTO"))
+ TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
+ TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
+ CodeGenOpts.EnableSplitLTOUnit);
+ }
+ MPM.addPass(
+ BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
}
break;
Modified: cfe/trunk/lib/Driver/SanitizerArgs.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/SanitizerArgs.cpp?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/SanitizerArgs.cpp (original)
+++ cfe/trunk/lib/Driver/SanitizerArgs.cpp Fri Jan 11 10:32:07 2019
@@ -207,6 +207,8 @@ bool SanitizerArgs::needsUnwindTables()
return Sanitizers.Mask & NeedsUnwindTables;
}
+bool SanitizerArgs::needsLTO() const { return Sanitizers.Mask & NeedsLTO; }
+
SanitizerArgs::SanitizerArgs(const ToolChain &TC,
const llvm::opt::ArgList &Args) {
SanitizerMask AllRemove = 0; // During the loop below, the accumulated set of
Modified: cfe/trunk/lib/Driver/ToolChains/Clang.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains/Clang.cpp?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/ToolChains/Clang.cpp (original)
+++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp Fri Jan 11 10:32:07 2019
@@ -5226,6 +5226,17 @@ void Clang::ConstructJob(Compilation &C,
CmdArgs.push_back("-fwhole-program-vtables");
}
+ bool RequiresSplitLTOUnit = WholeProgramVTables || Sanitize.needsLTO();
+ bool SplitLTOUnit =
+ Args.hasFlag(options::OPT_fsplit_lto_unit,
+ options::OPT_fno_split_lto_unit, RequiresSplitLTOUnit);
+ if (RequiresSplitLTOUnit && !SplitLTOUnit)
+ D.Diag(diag::err_drv_argument_not_allowed_with)
+ << "-fno-split-lto-unit"
+ << (WholeProgramVTables ? "-fwhole-program-vtables" : "-fsanitize=cfi");
+ if (SplitLTOUnit)
+ CmdArgs.push_back("-fsplit-lto-unit");
+
if (Arg *A = Args.getLastArg(options::OPT_fexperimental_isel,
options::OPT_fno_experimental_isel)) {
CmdArgs.push_back("-mllvm");
Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original)
+++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Fri Jan 11 10:32:07 2019
@@ -907,6 +907,7 @@ static bool ParseCodeGenArgs(CodeGenOpti
Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << S;
}
Opts.LTOUnit = Args.hasFlag(OPT_flto_unit, OPT_fno_lto_unit, false);
+ Opts.EnableSplitLTOUnit = Args.hasArg(OPT_fsplit_lto_unit);
if (Arg *A = Args.getLastArg(OPT_fthinlto_index_EQ)) {
if (IK.getLanguage() != InputKind::LLVM_IR)
Diags.Report(diag::err_drv_argument_only_allowed_with)
Modified: cfe/trunk/test/CodeGen/thinlto-distributed-cfi-devirt.ll
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/thinlto-distributed-cfi-devirt.ll?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/thinlto-distributed-cfi-devirt.ll (original)
+++ cfe/trunk/test/CodeGen/thinlto-distributed-cfi-devirt.ll Fri Jan 11 10:32:07 2019
@@ -4,7 +4,7 @@
; It additionally enables -fwhole-program-vtables to get more information in
; TYPE_IDs of GLOBALVAL_SUMMARY_BLOCK.
-; RUN: opt -thinlto-bc -o %t.o %s
+; RUN: opt -thinlto-bc -thinlto-split-lto-unit -o %t.o %s
; FIXME: Fix machine verifier issues and remove -verify-machineinstrs=0. PR39436.
; RUN: llvm-lto2 run -thinlto-distributed-indexes %t.o \
Modified: cfe/trunk/test/CodeGen/thinlto-distributed-cfi.ll
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/thinlto-distributed-cfi.ll?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/thinlto-distributed-cfi.ll (original)
+++ cfe/trunk/test/CodeGen/thinlto-distributed-cfi.ll Fri Jan 11 10:32:07 2019
@@ -2,7 +2,7 @@
; Backend test for distribute ThinLTO with CFI.
-; RUN: opt -thinlto-bc -o %t.o %s
+; RUN: opt -thinlto-bc -thinlto-split-lto-unit -o %t.o %s
; RUN: llvm-lto2 run -thinlto-distributed-indexes %t.o \
; RUN: -o %t2.index \
Modified: cfe/trunk/test/CodeGenCXX/no-lto-unit.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/no-lto-unit.cpp?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/no-lto-unit.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/no-lto-unit.cpp Fri Jan 11 10:32:07 2019
@@ -2,6 +2,8 @@
// RUN: llvm-dis -o - %t | FileCheck %s
// RUN: %clang_cc1 -flto=thin -flto-unit -fno-lto-unit -triple x86_64-unknown-linux -fvisibility hidden -emit-llvm-bc -o %t %s
// RUN: llvm-dis -o - %t | FileCheck %s
+// RUN: llvm-bcanalyzer -dump %t | FileCheck %s --check-prefix=NOLTOUNIT
+// NOLTOUNIT: <FLAGS op0=0/>
// CHECK-NOT: !type
class A {
Modified: cfe/trunk/test/CodeGenCXX/type-metadata-thinlto.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/type-metadata-thinlto.cpp?rev=350949&r1=350948&r2=350949&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/type-metadata-thinlto.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/type-metadata-thinlto.cpp Fri Jan 11 10:32:07 2019
@@ -1,5 +1,7 @@
-// RUN: %clang_cc1 -flto=thin -flto-unit -triple x86_64-unknown-linux -fvisibility hidden -emit-llvm-bc -o %t %s
+// RUN: %clang_cc1 -flto=thin -flto-unit -fsplit-lto-unit -triple x86_64-unknown-linux -fvisibility hidden -emit-llvm-bc -o %t %s
// RUN: llvm-modextract -o - -n 1 %t | llvm-dis | FileCheck %s
+// RUN: llvm-modextract -b -o - -n 1 %t | llvm-bcanalyzer -dump | FileCheck %s --check-prefix=LTOUNIT
+// LTOUNIT: <FLAGS op0=8/>
// CHECK: @_ZTV1A = linkonce_odr
class A {
Added: cfe/trunk/test/Driver/split-lto-unit.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/split-lto-unit.c?rev=350949&view=auto
==============================================================================
--- cfe/trunk/test/Driver/split-lto-unit.c (added)
+++ cfe/trunk/test/Driver/split-lto-unit.c Fri Jan 11 10:32:07 2019
@@ -0,0 +1,10 @@
+// RUN: %clang -target x86_64-unknown-linux -### %s -flto=thin 2>&1 | FileCheck --check-prefix=NOUNIT %s
+// RUN: %clang -target x86_64-unknown-linux -### %s -flto=thin -fsplit-lto-unit 2>&1 | FileCheck --check-prefix=UNIT %s
+// RUN: %clang -target x86_64-unknown-linux -### %s -flto=thin -fno-split-lto-unit 2>&1 | FileCheck --check-prefix=NOUNIT %s
+// RUN: %clang -target x86_64-unknown-linux -### %s -flto=thin -fno-split-lto-unit -fwhole-program-vtables 2>&1 | FileCheck --check-prefix=ERROR1 %s
+// RUN: %clang -target x86_64-unknown-linux -### %s -flto=thin -fno-split-lto-unit -fsanitize=cfi 2>&1 | FileCheck --check-prefix=ERROR2 %s
+
+// UNIT: "-fsplit-lto-unit"
+// NOUNIT-NOT: "-fsplit-lto-unit"
+// ERROR1: error: invalid argument '-fno-split-lto-unit' not allowed with '-fwhole-program-vtables'
+// ERROR2: error: invalid argument '-fno-split-lto-unit' not allowed with '-fsanitize=cfi'
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