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Enable WPD without lto #141777

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3 changes: 2 additions & 1 deletion clang/lib/CodeGen/CGVTables.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1359,7 +1359,8 @@ void CodeGenModule::EmitVTableTypeMetadata(const CXXRecordDecl *RD,
// Emit type metadata on vtables with LTO or IR instrumentation.
// In IR instrumentation, the type metadata is used to find out vtable
// definitions (for type profiling) among all global variables.
if (!getCodeGenOpts().LTOUnit && !getCodeGenOpts().hasProfileIRInstr())
if (!getCodeGenOpts().LTOUnit && !getCodeGenOpts().hasProfileIRInstr() &&
!getCodeGenOpts().WholeProgramVTables)
return;

CharUnits ComponentWidth = GetTargetTypeStoreSize(getVTableComponentType());
Expand Down
8 changes: 6 additions & 2 deletions clang/lib/Driver/ToolChains/Clang.cpp
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Expand Up @@ -7970,8 +7970,12 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
IsDeviceOffloadAction ? D.getLTOMode() : D.getOffloadLTOMode();
auto OtherIsUsingLTO = OtherLTOMode != LTOK_None;

if ((!IsUsingLTO && !OtherIsUsingLTO) ||
(IsPS4 && !UnifiedLTO && (D.getLTOMode() != LTOK_Full)))
if (!IsUsingLTO && !OtherIsUsingLTO && !UnifiedLTO) {
if (Arg *A = Args.getLastArg(options::OPT_O_Group))
if (!A->getOption().matches(options::OPT_O0))
CmdArgs.push_back("-fwhole-program-vtables");
} else if ((!IsUsingLTO && !OtherIsUsingLTO) ||
(IsPS4 && !UnifiedLTO && (D.getLTOMode() != LTOK_Full)))
D.Diag(diag::err_drv_argument_only_allowed_with)
<< "-fwhole-program-vtables"
<< ((IsPS4 && !UnifiedLTO) ? "-flto=full" : "-flto");
Expand Down
3 changes: 3 additions & 0 deletions llvm/lib/Passes/PassBuilderPipelines.cpp
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Expand Up @@ -1295,6 +1295,9 @@ PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
MPM.addPass(GlobalOptPass());
MPM.addPass(GlobalDCEPass());

if (Phase == ThinOrFullLTOPhase::None && Level != OptimizationLevel::O0)
MPM.addPass(WholeProgramDevirtPass(nullptr, nullptr));

return MPM;
}

Expand Down
83 changes: 50 additions & 33 deletions llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
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Expand Up @@ -60,7 +60,9 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/ModuleSummaryAnalysis.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/TypeMetadataUtils.h"
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/Bitcode/BitcodeWriter.h"
Expand Down Expand Up @@ -209,7 +211,8 @@ static cl::opt<WPDCheckMode> DevirtCheckMode(
cl::values(clEnumValN(WPDCheckMode::None, "none", "No checking"),
clEnumValN(WPDCheckMode::Trap, "trap", "Trap when incorrect"),
clEnumValN(WPDCheckMode::Fallback, "fallback",
"Fallback to indirect when incorrect")));
"Fallback to indirect when incorrect")),
cl::init(WPDCheckMode::Fallback));

namespace {
struct PatternList {
Expand Down Expand Up @@ -804,6 +807,12 @@ PreservedAnalyses WholeProgramDevirtPass::run(Module &M,
return PreservedAnalyses::all();
return PreservedAnalyses::none();
}
if (!ExportSummary) {
ProfileSummaryInfo PSI(M);
std::optional<ModuleSummaryIndex> Index;
Index.emplace(buildModuleSummaryIndex(M, nullptr, &PSI));
ExportSummary = Index.has_value() ? &Index.value() : nullptr;
}
if (!DevirtModule(M, AARGetter, OREGetter, LookupDomTree, ExportSummary,
ImportSummary)
.run())
Expand All @@ -814,8 +823,10 @@ PreservedAnalyses WholeProgramDevirtPass::run(Module &M,
// Enable whole program visibility if enabled by client (e.g. linker) or
// internal option, and not force disabled.
bool llvm::hasWholeProgramVisibility(bool WholeProgramVisibilityEnabledInLTO) {
return (WholeProgramVisibilityEnabledInLTO || WholeProgramVisibility) &&
!DisableWholeProgramVisibility;
if (WholeProgramVisibilityEnabledInLTO)
return (WholeProgramVisibilityEnabledInLTO || WholeProgramVisibility) &&
!DisableWholeProgramVisibility;
return true;
}

static bool
Expand Down Expand Up @@ -1099,9 +1110,9 @@ bool DevirtModule::tryFindVirtualCallTargets(

// We cannot perform whole program devirtualization analysis on a vtable
// with public LTO visibility.
if (TM.Bits->GV->getVCallVisibility() ==
GlobalObject::VCallVisibilityPublic)
return false;
// if (TM.Bits->GV->getVCallVisibility() ==
// GlobalObject::VCallVisibilityPublic)
// return false;

Function *Fn = nullptr;
Constant *C = nullptr;
Expand Down Expand Up @@ -1342,26 +1353,28 @@ bool DevirtModule::trySingleImplDevirt(
// If the only implementation has local linkage, we must promote to external
// to make it visible to thin LTO objects. We can only get here during the
// ThinLTO export phase.
if (TheFn->hasLocalLinkage()) {
std::string NewName = (TheFn->getName() + ".llvm.merged").str();

// Since we are renaming the function, any comdats with the same name must
// also be renamed. This is required when targeting COFF, as the comdat name
// must match one of the names of the symbols in the comdat.
if (Comdat *C = TheFn->getComdat()) {
if (C->getName() == TheFn->getName()) {
Comdat *NewC = M.getOrInsertComdat(NewName);
NewC->setSelectionKind(C->getSelectionKind());
for (GlobalObject &GO : M.global_objects())
if (GO.getComdat() == C)
GO.setComdat(NewC);
}
}

TheFn->setLinkage(GlobalValue::ExternalLinkage);
TheFn->setVisibility(GlobalValue::HiddenVisibility);
TheFn->setName(NewName);
}
// if (TheFn->hasLocalLinkage()) {
// std::string NewName = (TheFn->getName() + ".llvm.merged").str();

// // Since we are renaming the function, any comdats with the same name
// must
// // also be renamed. This is required when targeting COFF, as the comdat
// name
// // must match one of the names of the symbols in the comdat.
// if (Comdat *C = TheFn->getComdat()) {
// if (C->getName() == TheFn->getName()) {
// Comdat *NewC = M.getOrInsertComdat(NewName);
// NewC->setSelectionKind(C->getSelectionKind());
// for (GlobalObject &GO : M.global_objects())
// if (GO.getComdat() == C)
// GO.setComdat(NewC);
// }
// }

// TheFn->setLinkage(GlobalValue::ExternalLinkage);
// TheFn->setVisibility(GlobalValue::HiddenVisibility);
// TheFn->setName(NewName);
// }
if (ValueInfo TheFnVI = ExportSummary->getValueInfo(TheFn->getGUID()))
// Any needed promotion of 'TheFn' has already been done during
// LTO unit split, so we can ignore return value of AddCalls.
Expand Down Expand Up @@ -2321,6 +2334,9 @@ bool DevirtModule::run() {

Function *TypeTestFunc =
Intrinsic::getDeclarationIfExists(&M, Intrinsic::type_test);
if (!TypeTestFunc)
TypeTestFunc =
Intrinsic::getDeclarationIfExists(&M, Intrinsic::public_type_test);
Function *TypeCheckedLoadFunc =
Intrinsic::getDeclarationIfExists(&M, Intrinsic::type_checked_load);
Function *TypeCheckedLoadRelativeFunc = Intrinsic::getDeclarationIfExists(
Expand Down Expand Up @@ -2443,13 +2459,14 @@ bool DevirtModule::run() {
.WPDRes[S.first.ByteOffset];
if (tryFindVirtualCallTargets(TargetsForSlot, TypeMemberInfos,
S.first.ByteOffset, ExportSummary)) {

if (!trySingleImplDevirt(ExportSummary, TargetsForSlot, S.second, Res)) {
DidVirtualConstProp |=
tryVirtualConstProp(TargetsForSlot, S.second, Res, S.first);

tryICallBranchFunnel(TargetsForSlot, S.second, Res, S.first);
}
trySingleImplDevirt(ExportSummary, TargetsForSlot, S.second, Res);
// Following features are not needed for the case of enabling WPD without
// lto. if (!trySingleImplDevirt(ExportSummary, TargetsForSlot, S.second,
// Res)) { DidVirtualConstProp |=
// tryVirtualConstProp(TargetsForSlot, S.second, Res, S.first);

// tryICallBranchFunnel(TargetsForSlot, S.second, Res, S.first);
// }

// Collect functions devirtualized at least for one call site for stats.
if (RemarksEnabled || AreStatisticsEnabled())
Expand Down
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