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Revert "[ThinLTO] Add an auto-hide feature" 

This reverts commit r293970.

After more discussion, this belongs to the linker side and
there is no added value to do it at this level.

llvm-svn: 293993
This commit is contained in:
Mehdi Amini 2017-02-03 07:41:43 +00:00
parent e5f2bfaea9
commit 1380edf4ef
13 changed files with 54 additions and 129 deletions
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4
lld/test/ELF/lto/thin-archivecollision.ll
View File

@ -12,8 +12,8 @@
; RUN: llvm-nm %t | FileCheck %s
; CHECK: T _start
; CHECK: t blah
; CHECK: t foo
; CHECK: T blah
; CHECK: T foo
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-scei-ps4"

10
llvm/include/llvm/IR/ModuleSummaryIndex.h
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@ -126,14 +126,11 @@ public:
/// llvm.global_ctors that the linker does not know about.
unsigned LiveRoot : 1;
/// Indicate if the global value should be hidden.
unsigned AutoHide : 1;
/// Convenience Constructors
explicit GVFlags(GlobalValue::LinkageTypes Linkage,
bool NotEligibleToImport, bool LiveRoot, bool AutoHide)
bool NotEligibleToImport, bool LiveRoot)
: Linkage(Linkage), NotEligibleToImport(NotEligibleToImport),
LiveRoot(LiveRoot), AutoHide(AutoHide) {}
LiveRoot(LiveRoot) {}
};
private:
@ -201,9 +198,6 @@ public:
Flags.Linkage = Linkage;
}
/// Sets the visibility to be autohidden.
void setAutoHide() { Flags.AutoHide = true; }
/// Return true if this global value can't be imported.
bool notEligibleToImport() const { return Flags.NotEligibleToImport; }

2
llvm/include/llvm/IR/ModuleSummaryIndexYAML.h
View File

@ -79,7 +79,7 @@ template <> struct CustomMappingTraits<GlobalValueSummaryMapTy> {
auto &Elem = V[KeyInt];
for (auto &FSum : FSums) {
GlobalValueSummary::GVFlags GVFlags(GlobalValue::ExternalLinkage, false,
false, /* AutoHide */ false);
false);
Elem.push_back(llvm::make_unique<FunctionSummary>(
GVFlags, 0, ArrayRef<ValueInfo>{},
ArrayRef<FunctionSummary::EdgeTy>{}, std::move(FSum.TypeTests)));

8
llvm/include/llvm/LTO/LTO.h
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@ -53,18 +53,12 @@ void thinLTOResolveWeakForLinkerInIndex(
function_ref<void(StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes)>
recordNewLinkage);
/// This enum is used for the returned value of the callback passed to
/// thinLTOInternalizeAndPromoteInIndex, it indicates if a symbol can be made
/// Internal (only referenced from its defining object), Hidden (
/// outside the DSO), or Exported (exposed as public API for the DSO).
enum SummaryResolution { Internal, Hidden, Exported };
/// Update the linkages in the given \p Index to mark exported values
/// as external and non-exported values as internal. The ThinLTO backends
/// must apply the changes to the Module via thinLTOInternalizeModule.
void thinLTOInternalizeAndPromoteInIndex(
ModuleSummaryIndex &Index,
function_ref<SummaryResolution(StringRef, GlobalValue::GUID)> isExported);
function_ref<bool(StringRef, GlobalValue::GUID)> isExported);
namespace lto {

12
llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
View File

@ -190,8 +190,7 @@ computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
// FIXME: refactor this to use the same code that inliner is using.
F.isVarArg();
GlobalValueSummary::GVFlags Flags(F.getLinkage(), NotEligibleForImport,
/* LiveRoot = */ false,
/* AutoHide */ false);
/* LiveRoot = */ false);
auto FuncSummary = llvm::make_unique<FunctionSummary>(
Flags, NumInsts, RefEdges.takeVector(), CallGraphEdges.takeVector(),
TypeTests.takeVector());
@ -208,8 +207,7 @@ computeVariableSummary(ModuleSummaryIndex &Index, const GlobalVariable &V,
findRefEdges(&V, RefEdges, Visited);
bool NonRenamableLocal = isNonRenamableLocal(V);
GlobalValueSummary::GVFlags Flags(V.getLinkage(), NonRenamableLocal,
/* LiveRoot = */ false,
/* AutoHide */ false);
/* LiveRoot = */ false);
auto GVarSummary =
llvm::make_unique<GlobalVarSummary>(Flags, RefEdges.takeVector());
if (NonRenamableLocal)
@ -222,8 +220,7 @@ computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias &A,
DenseSet<GlobalValue::GUID> &CantBePromoted) {
bool NonRenamableLocal = isNonRenamableLocal(A);
GlobalValueSummary::GVFlags Flags(A.getLinkage(), NonRenamableLocal,
/* LiveRoot = */ false,
/* AutoHide */ false);
/* LiveRoot = */ false);
auto AS = llvm::make_unique<AliasSummary>(Flags, ArrayRef<ValueInfo>{});
auto *Aliasee = A.getBaseObject();
auto *AliaseeSummary = Index.getGlobalValueSummary(*Aliasee);
@ -342,8 +339,7 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex(
assert(GV->isDeclaration() && "Def in module asm already has definition");
GlobalValueSummary::GVFlags GVFlags(GlobalValue::InternalLinkage,
/* NotEligibleToImport */ true,
/* LiveRoot */ true,
/* AutoHide */ false);
/* LiveRoot */ true);
CantBePromoted.insert(GlobalValue::getGUID(Name));
// Create the appropriate summary type.
if (isa<Function>(GV)) {

9
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
View File

@ -800,14 +800,13 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
// like getDecodedLinkage() above. Any future change to the linkage enum and
// to getDecodedLinkage() will need to be taken into account here as above.
auto Linkage = GlobalValue::LinkageTypes(RawFlags & 0xF); // 4 bits
bool NotEligibleToImport = ((RawFlags >> 4) & 0x1) || Version < 3;
RawFlags = RawFlags >> 4;
bool NotEligibleToImport = (RawFlags & 0x1) || Version < 3;
// The LiveRoot flag wasn't introduced until version 3. For dead stripping
// to work correctly on earlier versions, we must conservatively treat all
// values as live.
bool LiveRoot = ((RawFlags >> 5) & 0x1) || Version < 3;
bool AutoHide = (RawFlags >> 6) & 0x1;
return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, LiveRoot,
AutoHide);
bool LiveRoot = (RawFlags & 0x2) || Version < 3;
return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, LiveRoot);
}
static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {

8
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
View File

@ -971,13 +971,13 @@ static unsigned getEncodedLinkage(const GlobalValue &GV) {
static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
uint64_t RawFlags = 0;
RawFlags |= Flags.NotEligibleToImport; // bool
RawFlags |= (Flags.LiveRoot << 1);
// Linkage don't need to be remapped at that time for the summary. Any future
// change to the getEncodedLinkage() function will need to be taken into
// account here as well.
RawFlags |= Flags.Linkage; // 4 bits linkage
RawFlags |= (Flags.NotEligibleToImport << 4); // bool
RawFlags |= (Flags.LiveRoot << 5); // bool
RawFlags |= (Flags.AutoHide << 6); // bool
RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
return RawFlags;
}

26
llvm/lib/LTO/LTO.cpp
View File

@ -203,14 +203,11 @@ void llvm::thinLTOResolveWeakForLinkerInIndex(
static void thinLTOInternalizeAndPromoteGUID(
GlobalValueSummaryList &GVSummaryList, GlobalValue::GUID GUID,
function_ref<SummaryResolution(StringRef, GlobalValue::GUID)> isExported) {
function_ref<bool(StringRef, GlobalValue::GUID)> isExported) {
for (auto &S : GVSummaryList) {
auto ExportResolution = isExported(S->modulePath(), GUID);
if (ExportResolution != Internal) {
if (isExported(S->modulePath(), GUID)) {
if (GlobalValue::isLocalLinkage(S->linkage()))
S->setLinkage(GlobalValue::ExternalLinkage);
if (ExportResolution == Hidden)
S->setAutoHide();
} else if (!GlobalValue::isLocalLinkage(S->linkage()))
S->setLinkage(GlobalValue::InternalLinkage);
}
@ -220,7 +217,7 @@ static void thinLTOInternalizeAndPromoteGUID(
// as external and non-exported values as internal.
void llvm::thinLTOInternalizeAndPromoteInIndex(
ModuleSummaryIndex &Index,
function_ref<SummaryResolution(StringRef, GlobalValue::GUID)> isExported) {
function_ref<bool(StringRef, GlobalValue::GUID)> isExported) {
for (auto &I : Index)
thinLTOInternalizeAndPromoteGUID(I.second, I.first, isExported);
}
@ -954,20 +951,11 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
const GlobalValueSummary *S) {
return ThinLTO.PrevailingModuleForGUID[GUID] == S->modulePath();
};
auto isExported = [&](StringRef ModuleIdentifier,
GlobalValue::GUID GUID) -> SummaryResolution {
auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
const auto &ExportList = ExportLists.find(ModuleIdentifier);
if ((ExportList != ExportLists.end() && ExportList->second.count(GUID)) ||
ExportedGUIDs.count(GUID)) {
// We could do better by hiding when a symbol is in
// GUIDPreservedSymbols because it is only referenced from regular LTO
// or from native files and not outside the final binary, but that's
// something the native linker could do as gwell.
if (GUIDPreservedSymbols.count(GUID))
return Exported;
return Hidden;
}
return Internal;
return (ExportList != ExportLists.end() &&
ExportList->second.count(GUID)) ||
ExportedGUIDs.count(GUID);
};
thinLTOInternalizeAndPromoteInIndex(ThinLTO.CombinedIndex, isExported);

58
llvm/lib/LTO/ThinLTOCodeGenerator.cpp
View File

@ -234,16 +234,16 @@ static void optimizeModule(Module &TheModule, TargetMachine &TM,
// Convert the PreservedSymbols map from "Name" based to "GUID" based.
static DenseSet<GlobalValue::GUID>
convertSymbolNamesToGUID(const StringSet<> &NamedSymbols,
computeGUIDPreservedSymbols(const StringSet<> &PreservedSymbols,
const Triple &TheTriple) {
DenseSet<GlobalValue::GUID> GUIDSymbols(NamedSymbols.size());
for (auto &Entry : NamedSymbols) {
DenseSet<GlobalValue::GUID> GUIDPreservedSymbols(PreservedSymbols.size());
for (auto &Entry : PreservedSymbols) {
StringRef Name = Entry.first();
if (TheTriple.isOSBinFormatMachO() && Name.size() > 0 && Name[0] == '_')
Name = Name.drop_front();
GUIDSymbols.insert(GlobalValue::getGUID(Name));
GUIDPreservedSymbols.insert(GlobalValue::getGUID(Name));
}
return GUIDSymbols;
return GUIDPreservedSymbols;
}
std::unique_ptr<MemoryBuffer> codegenModule(Module &TheModule,
@ -554,7 +554,10 @@ void ThinLTOCodeGenerator::preserveSymbol(StringRef Name) {
}
void ThinLTOCodeGenerator::crossReferenceSymbol(StringRef Name) {
CrossReferencedSymbols.insert(Name);
// FIXME: At the moment, we don't take advantage of this extra information,
// we're conservatively considering cross-references as preserved.
// CrossReferencedSymbols.insert(Name);
PreservedSymbols.insert(Name);
}
// TargetMachine factory
@ -617,7 +620,7 @@ void ThinLTOCodeGenerator::promote(Module &TheModule,
Index.collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
// Convert the preserved symbols set from string to GUID
auto GUIDPreservedSymbols = convertSymbolNamesToGUID(
auto GUIDPreservedSymbols = computeGUIDPreservedSymbols(
PreservedSymbols, Triple(TheModule.getTargetTriple()));
// Compute "dead" symbols, we don't want to import/export these!
@ -638,13 +641,11 @@ void ThinLTOCodeGenerator::promote(Module &TheModule,
// Promote the exported values in the index, so that they are promoted
// in the module.
auto isExported = [&](StringRef ModuleIdentifier,
GlobalValue::GUID GUID) -> SummaryResolution {
auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
const auto &ExportList = ExportLists.find(ModuleIdentifier);
if ((ExportList != ExportLists.end() && ExportList->second.count(GUID)) ||
GUIDPreservedSymbols.count(GUID))
return Exported;
return Internal;
return (ExportList != ExportLists.end() &&
ExportList->second.count(GUID)) ||
GUIDPreservedSymbols.count(GUID);
};
thinLTOInternalizeAndPromoteInIndex(Index, isExported);
@ -664,7 +665,7 @@ void ThinLTOCodeGenerator::crossModuleImport(Module &TheModule,
Index.collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
// Convert the preserved symbols set from string to GUID
auto GUIDPreservedSymbols = convertSymbolNamesToGUID(
auto GUIDPreservedSymbols = computeGUIDPreservedSymbols(
PreservedSymbols, Triple(TheModule.getTargetTriple()));
// Compute "dead" symbols, we don't want to import/export these!
@ -738,7 +739,7 @@ void ThinLTOCodeGenerator::internalize(Module &TheModule,
// Convert the preserved symbols set from string to GUID
auto GUIDPreservedSymbols =
convertSymbolNamesToGUID(PreservedSymbols, TMBuilder.TheTriple);
computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple);
// Collect for each module the list of function it defines (GUID -> Summary).
StringMap<GVSummaryMapTy> ModuleToDefinedGVSummaries(ModuleCount);
@ -760,13 +761,11 @@ void ThinLTOCodeGenerator::internalize(Module &TheModule,
return;
// Internalization
auto isExported = [&](StringRef ModuleIdentifier,
GlobalValue::GUID GUID) -> SummaryResolution {
auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
const auto &ExportList = ExportLists.find(ModuleIdentifier);
if ((ExportList != ExportLists.end() && ExportList->second.count(GUID)) ||
GUIDPreservedSymbols.count(GUID))
return Exported;
return Internal;
return (ExportList != ExportLists.end() &&
ExportList->second.count(GUID)) ||
GUIDPreservedSymbols.count(GUID);
};
thinLTOInternalizeAndPromoteInIndex(Index, isExported);
thinLTOInternalizeModule(TheModule,
@ -895,9 +894,7 @@ void ThinLTOCodeGenerator::run() {
// Convert the preserved symbols set from string to GUID, this is needed for
// computing the caching hash and the internalization.
auto GUIDPreservedSymbols =
convertSymbolNamesToGUID(PreservedSymbols, TMBuilder.TheTriple);
auto GUIDCrossRefSymbols =
convertSymbolNamesToGUID(CrossReferencedSymbols, TMBuilder.TheTriple);
computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple);
// Compute "dead" symbols, we don't want to import/export these!
auto DeadSymbols = computeDeadSymbols(*Index, GUIDPreservedSymbols);
@ -919,16 +916,11 @@ void ThinLTOCodeGenerator::run() {
// impacts the caching.
resolveWeakForLinkerInIndex(*Index, ResolvedODR);
auto isExported = [&](StringRef ModuleIdentifier,
GlobalValue::GUID GUID) -> SummaryResolution {
if (GUIDPreservedSymbols.count(GUID))
return Exported;
if (GUIDCrossRefSymbols.count(GUID))
return Hidden;
auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
const auto &ExportList = ExportLists.find(ModuleIdentifier);
if (ExportList != ExportLists.end() && ExportList->second.count(GUID))
return Hidden;
return Internal;
return (ExportList != ExportLists.end() &&
ExportList->second.count(GUID)) ||
GUIDPreservedSymbols.count(GUID);
};
// Use global summary-based analysis to identify symbols that can be

7
llvm/lib/Transforms/IPO/FunctionImport.cpp
View File

@ -644,13 +644,6 @@ void llvm::thinLTOInternalizeModule(Module &TheModule,
return !GlobalValue::isLocalLinkage(Linkage);
};
// Try to auto-hide the symbols.
for (auto &GO : TheModule.global_objects()) {
const auto &GS = DefinedGlobals.find(GO.getGUID());
if (GS != DefinedGlobals.end() && GS->second->flags().AutoHide)
GO.setVisibility(GlobalValue::HiddenVisibility);
}
// FIXME: See if we can just internalize directly here via linkage changes
// based on the index, rather than invoking internalizeModule.
llvm::internalizeModule(TheModule, MustPreserveGV);

6
llvm/test/ThinLTO/X86/Inputs/weak_autohide.ll
View File

@ -1,6 +0,0 @@
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.11.0"
define weak_odr void @weakodrfunc() {
ret void
}

7
llvm/test/ThinLTO/X86/deadstrip.ll
View File

@ -3,7 +3,7 @@
; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t1.bc %t2.bc
; RUN: llvm-lto -exported-symbol=_main -thinlto-action=promote %t1.bc -thinlto-index=%t.index.bc -o - | llvm-lto -exported-symbol=_main -thinlto-action=internalize -thinlto-index %t.index.bc -thinlto-module-id=%t1.bc - -o - | llvm-dis -o - | FileCheck %s
; RUN: llvm-lto -exported-symbol=_main -thinlto-action=promote %t2.bc -thinlto-index=%t.index.bc -o - | llvm-lto -exported-symbol=_main -thinlto-action=internalize -thinlto-index %t.index.bc -thinlto-module-id=%t2.bc - -o - | llvm-dis -o - | FileCheck %s --check-prefix=CHECK2-LTO
; RUN: llvm-lto -exported-symbol=_main -thinlto-action=promote %t2.bc -thinlto-index=%t.index.bc -o - | llvm-lto -exported-symbol=_main -thinlto-action=internalize -thinlto-index %t.index.bc -thinlto-module-id=%t2.bc - -o - | llvm-dis -o - | FileCheck %s --check-prefix=CHECK2
; RUN: llvm-lto -exported-symbol=_main -thinlto-action=run %t1.bc %t2.bc
; RUN: llvm-nm %t1.bc.thinlto.o | FileCheck %s --check-prefix=CHECK-NM
@ -19,7 +19,7 @@
; RUN: -r %t2.bc,_dead_func,pl \
; RUN: -r %t2.bc,_another_dead_func,pl
; RUN: llvm-dis < %t.out.0.3.import.bc | FileCheck %s
; RUN: llvm-dis < %t.out.1.3.import.bc | FileCheck %s --check-prefix=CHECK2-LTO2
; RUN: llvm-dis < %t.out.1.3.import.bc | FileCheck %s --check-prefix=CHECK2
; RUN: llvm-nm %t.out.1 | FileCheck %s --check-prefix=CHECK2-NM
; Dead-stripping on the index allows to internalize these,
@ -34,8 +34,7 @@
; Make sure we didn't internalize @boo, which is reachable via
; llvm.global_ctors
; CHECK2-LTO: define void @boo()
; CHECK2-LTO2: define hidden void @boo()
; CHECK2: define void @boo()
; We should have eventually revoved @baz since it was internalized and unused
; CHECK2-NM-NOT: _baz

24
llvm/test/ThinLTO/X86/weak_autohide.ll
View File

@ -1,24 +0,0 @@
; RUN: opt -module-summary %s -o %t1.bc
; RUN: opt -module-summary %p/Inputs/weak_autohide.ll -o %t2.bc
; RUN: llvm-lto2 %t1.bc %t2.bc -o %t.o -save-temps \
; RUN: -r=%t1.bc,_strong_func,pxl \
; RUN: -r=%t1.bc,_weakodrfunc,pl \
; RUN: -r=%t2.bc,_weakodrfunc,l
; RUN: llvm-dis < %t.o.0.2.internalize.bc | FileCheck %s --check-prefix=AUTOHIDE
; AUTOHIDE: weak_odr hidden void @weakodrfunc
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.11.0"
define weak_odr void @weakodrfunc() #0 {
ret void
}
define void @strong_func() #0 {
call void @weakodrfunc()
ret void
}