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[ThinLTO] Only emit referenced type id records in index files 

Summary:
Currently all type ids are emitted into the index file when it is
written. For distributed ThinLTO, that meant that all type ids were
being duplicated into every single distributed index file, regardless of
whether they were referenced, leading to huge amounts of unnecessary
duplication and size bloat.

Keep track of the type id GUIDs actually referenced by the GV summary
records being emitted, and only emit those type IDs.

Add a new test, and fix test/Assembler/thinlto-summary.ll so that all
type ids are referenced to prevent deletion in that test.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, vitalybuka, llvm-commits

Differential Revision: https://reviews.llvm.org/D49565

llvm-svn: 337503
This commit is contained in:
Teresa Johnson 2018-07-19 22:25:56 +00:00
parent c12c5d421f
commit 0c432b1a70
4 changed files with 109 additions and 7 deletions
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24
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
View File

@ -3353,10 +3353,14 @@ void IndexBitcodeWriter::writeModStrings() {
/// Write the function type metadata related records that need to appear before
/// a function summary entry (whether per-module or combined).
static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
FunctionSummary *FS) {
if (!FS->type_tests().empty())
static void writeFunctionTypeMetadataRecords(
BitstreamWriter &Stream, FunctionSummary *FS,
std::set<GlobalValue::GUID> &ReferencedTypeIds) {
if (!FS->type_tests().empty()) {
Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
for (auto &TT : FS->type_tests())
ReferencedTypeIds.insert(TT);
}
SmallVector<uint64_t, 64> Record;
@ -3368,6 +3372,7 @@ static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
for (auto &VF : VFs) {
Record.push_back(VF.GUID);
Record.push_back(VF.Offset);
ReferencedTypeIds.insert(VF.GUID);
}
Stream.EmitRecord(Ty, Record);
};
@ -3382,6 +3387,7 @@ static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
for (auto &VC : VCs) {
Record.clear();
Record.push_back(VC.VFunc.GUID);
ReferencedTypeIds.insert(VC.VFunc.GUID);
Record.push_back(VC.VFunc.Offset);
Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
Stream.EmitRecord(Ty, Record);
@ -3447,7 +3453,8 @@ void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
NameVals.push_back(ValueID);
FunctionSummary *FS = cast<FunctionSummary>(Summary);
writeFunctionTypeMetadataRecords(Stream, FS);
std::set<GlobalValue::GUID> ReferencedTypeIds;
writeFunctionTypeMetadataRecords(Stream, FS, ReferencedTypeIds);
NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
NameVals.push_back(FS->instCount());
@ -3702,6 +3709,10 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
SmallVector<uint64_t, 64> NameVals;
// Set that will be populated during call to writeFunctionTypeMetadataRecords
// with the type ids referenced by this index file.
std::set<GlobalValue::GUID> ReferencedTypeIds;
// For local linkage, we also emit the original name separately
// immediately after the record.
auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
@ -3753,7 +3764,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
}
auto *FS = cast<FunctionSummary>(S);
writeFunctionTypeMetadataRecords(Stream, FS);
writeFunctionTypeMetadataRecords(Stream, FS, ReferencedTypeIds);
NameVals.push_back(*ValueId);
NameVals.push_back(Index.getModuleId(FS->modulePath()));
@ -3862,6 +3873,9 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
if (!Index.typeIds().empty()) {
for (auto &S : Index.typeIds()) {
// Skip if not referenced in any GV summary within this index file.
if (!ReferencedTypeIds.count(GlobalValue::getGUID(S.first)))
continue;
writeTypeIdSummaryRecord(NameVals, StrtabBuilder, S.first, S.second);
Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
NameVals.clear();

4
llvm/test/Assembler/thinlto-summary.ll
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@ -50,7 +50,7 @@
^20 = gv: (guid: 19, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 8, typeIdInfo: (typeTestAssumeVCalls: (vFuncId: (^27, offset: 16))))))
^21 = gv: (guid: 20, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 5, typeIdInfo: (typeCheckedLoadVCalls: (vFuncId: (^25, offset: 16))))))
^22 = gv: (guid: 21, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 15, typeIdInfo: (typeTestAssumeConstVCalls: (vFuncId: (^27, offset: 16), args: (42), vFuncId: (^27, offset: 24), args: (43))))))
^23 = gv: (guid: 22, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 5, typeIdInfo: (typeCheckedLoadConstVCalls: (vFuncId: (^27, offset: 16), args: (42))))))
^23 = gv: (guid: 22, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 5, typeIdInfo: (typeCheckedLoadConstVCalls: (vFuncId: (^28, offset: 16), args: (42))))))
; Test TypeId summaries:
@ -88,7 +88,7 @@
; CHECK: ^20 = gv: (guid: 19, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 8, typeIdInfo: (typeTestAssumeVCalls: (vFuncId: (^27, offset: 16))))))
; CHECK: ^21 = gv: (guid: 20, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 5, typeIdInfo: (typeCheckedLoadVCalls: (vFuncId: (^25, offset: 16))))))
; CHECK: ^22 = gv: (guid: 21, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 15, typeIdInfo: (typeTestAssumeConstVCalls: (vFuncId: (^27, offset: 16), args: (42), vFuncId: (^27, offset: 24), args: (43))))))
; CHECK: ^23 = gv: (guid: 22, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 5, typeIdInfo: (typeCheckedLoadConstVCalls: (vFuncId: (^27, offset: 16), args: (42))))))
; CHECK: ^23 = gv: (guid: 22, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0), insts: 5, typeIdInfo: (typeCheckedLoadConstVCalls: (vFuncId: (^28, offset: 16), args: (42))))))
; CHECK: ^24 = typeid: (name: "_ZTS1A", summary: (typeTestRes: (kind: allOnes, sizeM1BitWidth: 7), wpdResolutions: ((offset: 0, wpdRes: (kind: branchFunnel)), (offset: 8, wpdRes: (kind: singleImpl, singleImplName: "_ZN1A1nEi")), (offset: 16, wpdRes: (kind: indir, resByArg: (args: (1, 2), byArg: (kind: indir, byte: 2, bit: 3), args: (3), byArg: (kind: uniformRetVal, info: 1), args: (4), byArg: (kind: uniqueRetVal, info: 1), args: (5), byArg: (kind: virtualConstProp))))))) ; guid = 7004155349499253778
; CHECK: ^25 = typeid: (name: "_ZTS1B", summary: (typeTestRes: (kind: inline, sizeM1BitWidth: 0, alignLog2: 1, sizeM1: 2, bitMask: 3, inlineBits: 4))) ; guid = 6203814149063363976
; CHECK: ^26 = typeid: (name: "_ZTS1C", summary: (typeTestRes: (kind: single, sizeM1BitWidth: 0))) ; guid = 1884921850105019584

28
llvm/test/ThinLTO/X86/Inputs/cfi-distributed.ll Normal file
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@ -0,0 +1,28 @@
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-grtev4-linux-gnu"
%struct.B2 = type { %struct.A2 }
%struct.A2 = type { i32 (...)** }
@_ZTV1B2 = constant { [3 x i8*] } { [3 x i8*] [i8* undef, i8* undef, i8* undef] }, !type !0
define void @test2(i8* %b) {
entry:
%0 = bitcast i8* %b to i8**
%vtable2 = load i8*, i8** %0
%1 = tail call i1 @llvm.type.test(i8* %vtable2, metadata !"_ZTS1A2")
br i1 %1, label %cont, label %trap
trap:
tail call void @llvm.trap()
unreachable
cont:
ret void
}
declare i1 @llvm.type.test(i8*, metadata)
declare void @llvm.trap()
!0 = !{i64 16, !"_ZTS1A2"}
!1 = !{i64 16, !"_ZTS1B2"}

60
llvm/test/ThinLTO/X86/cfi-distributed.ll Normal file
View File

@ -0,0 +1,60 @@
; REQUIRES: x86-registered-target
; Test to ensure that only referenced type ID records are emitted into
; each distributed index file.
; RUN: opt -thinlto-bc -o %t1.o %s
; RUN: opt -thinlto-bc -o %t2.o %p/Inputs/cfi-distributed.ll
; RUN: llvm-lto2 run -thinlto-distributed-indexes %t1.o %t2.o \
; RUN: -o %t3 \
; RUN: -r=%t1.o,test,px \
; RUN: -r=%t1.o,_ZTV1B, \
; RUN: -r=%t1.o,_ZTV1B,px \
; RUN: -r=%t1.o,test2, \
; RUN: -r=%t2.o,test2,px \
; RUN: -r=%t2.o,_ZTV1B2, \
; RUN: -r=%t2.o,_ZTV1B2,px
; Since @test calls @test2, the latter should be imported here and the
; first index file should reference both type ids.
; RUN: llvm-dis %t1.o.thinlto.bc -o - | FileCheck %s --check-prefix=INDEX1
; INDEX1: typeid: (name: "_ZTS1A"
; INDEX1: typeid: (name: "_ZTS1A2"
; The second index file, corresponding to @test2, should only contain the
; typeid for _ZTS1A.
; RUN: llvm-dis %t2.o.thinlto.bc -o - | FileCheck %s --check-prefix=INDEX2
; INDEX2-NOT: typeid: (name: "_ZTS1A"
; INDEX2: typeid: (name: "_ZTS1A2"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-grtev4-linux-gnu"
%struct.B = type { %struct.A }
%struct.A = type { i32 (...)** }
@_ZTV1B = constant { [3 x i8*] } { [3 x i8*] [i8* undef, i8* undef, i8* undef] }, !type !0
define void @test(i8* %b) {
entry:
tail call void @test2(i8* %b)
%0 = bitcast i8* %b to i8**
%vtable2 = load i8*, i8** %0
%1 = tail call i1 @llvm.type.test(i8* %vtable2, metadata !"_ZTS1A")
br i1 %1, label %cont, label %trap
trap:
tail call void @llvm.trap()
unreachable
cont:
ret void
}
declare void @test2(i8*)
declare i1 @llvm.type.test(i8*, metadata)
declare void @llvm.trap()
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTS1B"}