LTO: Redesign the CFI !aliases metadata. #150690
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Created using spr 1.3.6-beta.1
You can test this locally with the following command:git-clang-format --diff HEAD~1 HEAD --extensions h,cpp -- llvm/include/llvm/LTO/LTO.h llvm/lib/LTO/LTO.cpp llvm/lib/Transforms/IPO/LowerTypeTests.cpp llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cppView the diff from clang-format here.diff --git a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
index 5abfa687a..b5dfa6ae7 100644
--- a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
+++ b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
@@ -1138,9 +1138,9 @@ void LowerTypeTestsModule::importFunction(Function *F,
FDecl->setVisibility(Visibility);
Visibility = GlobalValue::HiddenVisibility;
- // Update aliases pointing to this function to also include the ".cfi" suffix,
- // We expect the jump table entry to either point to the real function or an
- // alias. Redirect all other users to the jump table entry.
+ // Update aliases pointing to this function to also include the ".cfi"
+ // suffix, We expect the jump table entry to either point to the real
+ // function or an alias. Redirect all other users to the jump table entry.
for (auto &U : F->uses()) {
if (auto *A = dyn_cast<GlobalAlias>(U.getUser())) {
std::string AliasName = A->getName().str() + ".cfi";
|
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@llvm/pr-subscribers-llvm-transforms @llvm/pr-subscribers-lto Author: Peter Collingbourne (pcc) ChangesWith the current aliases metadata we lose information about which groups In this redesign of the aliases metadata, we stop representing the Fixes #150075. Full diff: https://github.com/llvm/llvm-project/pull/150690.diff 7 Files Affected:
diff --git a/llvm/include/llvm/LTO/LTO.h b/llvm/include/llvm/LTO/LTO.h
index d8e632b5a49d5..290b0ef4e2aa4 100644
--- a/llvm/include/llvm/LTO/LTO.h
+++ b/llvm/include/llvm/LTO/LTO.h
@@ -541,20 +541,21 @@ class LTO {
void addModuleToGlobalRes(ArrayRef<InputFile::Symbol> Syms,
ArrayRef<SymbolResolution> Res, unsigned Partition,
bool InSummary);
-
- // These functions take a range of symbol resolutions [ResI, ResE) and consume
- // the resolutions used by a single input module by incrementing ResI. After
- // these functions return, [ResI, ResE) will refer to the resolution range for
- // the remaining modules in the InputFile.
Error addModule(InputFile &Input, unsigned ModI,
- const SymbolResolution *&ResI, const SymbolResolution *ResE);
+ const SymbolResolution *&ResI,
+ ArrayRef<SymbolResolution> Res);
Expected<RegularLTOState::AddedModule>
- addRegularLTO(BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms,
- const SymbolResolution *&ResI, const SymbolResolution *ResE);
+ addRegularLTO(InputFile &Input, BitcodeModule BM,
+ ArrayRef<InputFile::Symbol> Syms, const SymbolResolution *&ResI,
+ ArrayRef<SymbolResolution> Res);
Error linkRegularLTO(RegularLTOState::AddedModule Mod,
bool LivenessFromIndex);
+ // This function takes a range of symbol resolutions [ResI, ResE) and consume
+ // the resolutions used by a single input module by incrementing ResI. After
+ // these functions return, [ResI, ResE) will refer to the resolution range for
+ // the remaining modules in the InputFile.
Error addThinLTO(BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms,
const SymbolResolution *&ResI, const SymbolResolution *ResE);
diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 73e79c08a56ca..459b6e8b2c803 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -744,7 +744,7 @@ Error LTO::add(std::unique_ptr<InputFile> Input,
const SymbolResolution *ResI = Res.begin();
for (unsigned I = 0; I != Input->Mods.size(); ++I)
- if (Error Err = addModule(*Input, I, ResI, Res.end()))
+ if (Error Err = addModule(*Input, I, ResI, Res))
return Err;
assert(ResI == Res.end());
@@ -753,7 +753,7 @@ Error LTO::add(std::unique_ptr<InputFile> Input,
Error LTO::addModule(InputFile &Input, unsigned ModI,
const SymbolResolution *&ResI,
- const SymbolResolution *ResE) {
+ ArrayRef<SymbolResolution> Res) {
Expected<BitcodeLTOInfo> LTOInfo = Input.Mods[ModI].getLTOInfo();
if (!LTOInfo)
return LTOInfo.takeError();
@@ -782,16 +782,16 @@ Error LTO::addModule(InputFile &Input, unsigned ModI,
bool IsThinLTO = LTOInfo->IsThinLTO && (LTOMode != LTOK_UnifiedRegular);
auto ModSyms = Input.module_symbols(ModI);
- addModuleToGlobalRes(ModSyms, {ResI, ResE},
+ addModuleToGlobalRes(ModSyms, {ResI, Res.end()},
IsThinLTO ? ThinLTO.ModuleMap.size() + 1 : 0,
LTOInfo->HasSummary);
if (IsThinLTO)
- return addThinLTO(BM, ModSyms, ResI, ResE);
+ return addThinLTO(BM, ModSyms, ResI, Res.end());
RegularLTO.EmptyCombinedModule = false;
Expected<RegularLTOState::AddedModule> ModOrErr =
- addRegularLTO(BM, ModSyms, ResI, ResE);
+ addRegularLTO(Input, BM, ModSyms, ResI, Res);
if (!ModOrErr)
return ModOrErr.takeError();
@@ -839,10 +839,9 @@ handleNonPrevailingComdat(GlobalValue &GV,
// Add a regular LTO object to the link.
// The resulting module needs to be linked into the combined LTO module with
// linkRegularLTO.
-Expected<LTO::RegularLTOState::AddedModule>
-LTO::addRegularLTO(BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms,
- const SymbolResolution *&ResI,
- const SymbolResolution *ResE) {
+Expected<LTO::RegularLTOState::AddedModule> LTO::addRegularLTO(
+ InputFile &Input, BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms,
+ const SymbolResolution *&ResI, ArrayRef<SymbolResolution> Res) {
RegularLTOState::AddedModule Mod;
Expected<std::unique_ptr<Module>> MOrErr =
BM.getLazyModule(RegularLTO.Ctx, /*ShouldLazyLoadMetadata*/ true,
@@ -855,13 +854,34 @@ LTO::addRegularLTO(BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms,
if (Error Err = M.materializeMetadata())
return std::move(Err);
- // If cfi.functions is present and we are in regular LTO mode, LowerTypeTests
- // will rename local functions in the merged module as "<function name>.1".
- // This causes linking errors, since other parts of the module expect the
- // original function name.
- if (LTOMode == LTOK_UnifiedRegular)
+ if (LTOMode == LTOK_UnifiedRegular) {
+ // cfi.functions metadata is intended to be used with ThinLTO and may
+ // trigger invalid IR transformations if they are present when doing regular
+ // LTO, so delete it.
if (NamedMDNode *CfiFunctionsMD = M.getNamedMetadata("cfi.functions"))
M.eraseNamedMetadata(CfiFunctionsMD);
+ } else if (NamedMDNode *AliasesMD = M.getNamedMetadata("aliases")) {
+ // Delete aliases entries for non-prevailing symbols on the ThinLTO side of
+ // this input file.
+ std::set<StringRef> Prevailing;
+ for (auto P : zip(Input.symbols(), Res))
+ if (std::get<1>(P).Prevailing && !std::get<0>(P).getIRName().empty())
+ Prevailing.insert(std::get<0>(P).getIRName());
+ std::vector<MDNode *> AliasGroups;
+ for (MDNode *AliasGroup : AliasesMD->operands()) {
+ std::vector<Metadata *> Aliases;
+ for (Metadata *Alias : AliasGroup->operands()) {
+ if (isa<MDString>(Alias) &&
+ Prevailing.count(cast<MDString>(Alias)->getString()))
+ Aliases.push_back(Alias);
+ }
+ if (Aliases.size() > 1)
+ AliasGroups.push_back(MDTuple::get(RegularLTO.Ctx, Aliases));
+ }
+ AliasesMD->clearOperands();
+ for (MDNode *G : AliasGroups)
+ AliasesMD->addOperand(G);
+ }
UpgradeDebugInfo(M);
@@ -899,7 +919,7 @@ LTO::addRegularLTO(BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms,
std::set<const Comdat *> NonPrevailingComdats;
SmallSet<StringRef, 2> NonPrevailingAsmSymbols;
for (const InputFile::Symbol &Sym : Syms) {
- assert(ResI != ResE);
+ assert(ResI != Res.end());
SymbolResolution Res = *ResI++;
assert(MsymI != MsymE);
diff --git a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
index 486205c8a3848..392f3240c0ae8 100644
--- a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
+++ b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
@@ -349,6 +349,7 @@ struct ICallBranchFunnel final
struct ScopedSaveAliaseesAndUsed {
Module &M;
+ std::set<GlobalAlias *> *ExcludedAliases;
SmallVector<GlobalValue *, 4> Used, CompilerUsed;
std::vector<std::pair<GlobalAlias *, Function *>> FunctionAliases;
std::vector<std::pair<GlobalIFunc *, Function *>> ResolverIFuncs;
@@ -377,7 +378,9 @@ struct ScopedSaveAliaseesAndUsed {
Vec.resize(NonFuncBegin - Vec.begin());
}
- ScopedSaveAliaseesAndUsed(Module &M) : M(M) {
+ ScopedSaveAliaseesAndUsed(Module &M,
+ std::set<GlobalAlias *> *ExcludedAliases = nullptr)
+ : M(M), ExcludedAliases(ExcludedAliases) {
// The users of this class want to replace all function references except
// for aliases and llvm.used/llvm.compiler.used with references to a jump
// table. We avoid replacing aliases in order to avoid introducing a double
@@ -396,8 +399,9 @@ struct ScopedSaveAliaseesAndUsed {
for (auto &GA : M.aliases()) {
// FIXME: This should look past all aliases not just interposable ones,
// see discussion on D65118.
- if (auto *F = dyn_cast<Function>(GA.getAliasee()->stripPointerCasts()))
- FunctionAliases.push_back({&GA, F});
+ if (!ExcludedAliases || !ExcludedAliases->count(&GA))
+ if (auto *F = dyn_cast<Function>(GA.getAliasee()->stripPointerCasts()))
+ FunctionAliases.push_back({&GA, F});
}
for (auto &GI : M.ifuncs())
@@ -2137,6 +2141,18 @@ bool LowerTypeTestsModule::lower() {
if (auto Alias = dyn_cast<AliasSummary>(RefGVS.get()))
AddressTaken.insert(Alias->getAliaseeGUID());
}
+ auto IsAddressTaken = [&](GlobalValue::GUID GUID) {
+ if (AddressTaken.count(GUID))
+ return true;
+ auto VI = ExportSummary->getValueInfo(GUID);
+ if (!VI)
+ return false;
+ for (auto &I : VI.getSummaryList())
+ if (auto Alias = dyn_cast<AliasSummary>(I.get()))
+ if (AddressTaken.count(Alias->getAliaseeGUID()))
+ return true;
+ return false;
+ };
for (auto *FuncMD : CfiFunctionsMD->operands()) {
assert(FuncMD->getNumOperands() >= 2);
StringRef FunctionName =
@@ -2153,7 +2169,7 @@ bool LowerTypeTestsModule::lower() {
// have no live references (and are not exported with cross-DSO CFI.)
if (!ExportSummary->isGUIDLive(GUID))
continue;
- if (!AddressTaken.count(GUID)) {
+ if (!IsAddressTaken(GUID)) {
if (!CrossDsoCfi || Linkage != CFL_Definition)
continue;
@@ -2227,6 +2243,44 @@ bool LowerTypeTestsModule::lower() {
}
}
+ struct AliasToCreate {
+ Function *Alias;
+ std::string TargetName;
+ };
+ std::vector<AliasToCreate> AliasesToCreate;
+
+ // Parse alias data to replace stand-in function declarations for aliases
+ // with an alias to the intended target.
+ std::set<GlobalAlias *> ExcludedAliases;
+ if (ExportSummary) {
+ if (NamedMDNode *AliasesMD = M.getNamedMetadata("aliases")) {
+ for (auto *AliasMD : AliasesMD->operands()) {
+ std::vector<Function *> Aliases;
+ for (Metadata *MD : AliasMD->operands()) {
+ auto *MDS = dyn_cast<MDString>(MD);
+ if (!MDS)
+ continue;
+ StringRef AliasName = MDS->getString();
+ if (!ExportedFunctions.count(AliasName))
+ continue;
+ auto *AliasF = M.getFunction(AliasName);
+ if (AliasF)
+ Aliases.push_back(AliasF);
+ }
+
+ if (Aliases.empty())
+ continue;
+
+ for (unsigned I = 1; I != Aliases.size(); ++I) {
+ auto *AliasF = Aliases[I];
+ ExportedFunctions.erase(AliasF->getName());
+ AliasesToCreate.push_back(
+ {AliasF, std::string(Aliases[0]->getName())});
+ }
+ }
+ }
+ }
+
DenseMap<GlobalObject *, GlobalTypeMember *> GlobalTypeMembers;
for (GlobalObject &GO : M.global_objects()) {
if (isa<GlobalVariable>(GO) && GO.isDeclarationForLinker())
@@ -2374,7 +2428,7 @@ bool LowerTypeTestsModule::lower() {
return false;
{
- ScopedSaveAliaseesAndUsed S(M);
+ ScopedSaveAliaseesAndUsed S(M, &ExcludedAliases);
// For each disjoint set we found...
for (const auto &C : GlobalClasses) {
if (!C->isLeader())
@@ -2414,49 +2468,18 @@ bool LowerTypeTestsModule::lower() {
allocateByteArrays();
- // Parse alias data to replace stand-in function declarations for aliases
- // with an alias to the intended target.
- if (ExportSummary) {
- if (NamedMDNode *AliasesMD = M.getNamedMetadata("aliases")) {
- for (auto *AliasMD : AliasesMD->operands()) {
- assert(AliasMD->getNumOperands() >= 4);
- StringRef AliasName =
- cast<MDString>(AliasMD->getOperand(0))->getString();
- StringRef Aliasee = cast<MDString>(AliasMD->getOperand(1))->getString();
-
- if (auto It = ExportedFunctions.find(Aliasee);
- It == ExportedFunctions.end() ||
- It->second.Linkage != CFL_Definition || !M.getNamedAlias(Aliasee))
- continue;
-
- GlobalValue::VisibilityTypes Visibility =
- static_cast<GlobalValue::VisibilityTypes>(
- cast<ConstantAsMetadata>(AliasMD->getOperand(2))
- ->getValue()
- ->getUniqueInteger()
- .getZExtValue());
- bool Weak =
- static_cast<bool>(cast<ConstantAsMetadata>(AliasMD->getOperand(3))
- ->getValue()
- ->getUniqueInteger()
- .getZExtValue());
-
- auto *Alias = GlobalAlias::create("", M.getNamedAlias(Aliasee));
- Alias->setVisibility(Visibility);
- if (Weak)
- Alias->setLinkage(GlobalValue::WeakAnyLinkage);
-
- if (auto *F = M.getFunction(AliasName)) {
- Alias->takeName(F);
- F->replaceAllUsesWith(Alias);
- F->eraseFromParent();
- } else {
- Alias->setName(AliasName);
- }
- }
- }
- }
-
+ for (auto A : AliasesToCreate) {
+ auto *Target = M.getNamedValue(A.TargetName);
+ if (!isa<GlobalAlias>(Target))
+ continue;
+ auto *AliasGA = GlobalAlias::create("", Target);
+ AliasGA->setVisibility(A.Alias->getVisibility());
+ AliasGA->setLinkage(A.Alias->getLinkage());
+ AliasGA->takeName(A.Alias);
+ A.Alias->replaceAllUsesWith(AliasGA);
+ A.Alias->eraseFromParent();
+ }
+
// Emit .symver directives for exported functions, if they exist.
if (ExportSummary) {
if (NamedMDNode *SymversMD = M.getNamedMetadata("symvers")) {
diff --git a/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp b/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
index e276376f21583..019831f550cbd 100644
--- a/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
+++ b/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
@@ -384,6 +384,10 @@ void splitAndWriteThinLTOBitcode(
for (auto &F : M)
if ((!F.hasLocalLinkage() || F.hasAddressTaken()) && HasTypeMetadata(&F))
CfiFunctions.insert(&F);
+ for (auto &A : M.aliases())
+ if (auto *F = dyn_cast<Function>(A.getAliasee()))
+ if (HasTypeMetadata(F))
+ CfiFunctions.insert(&A);
// Remove all globals with type metadata, globals with comdats that live in
// MergedM, and aliases pointing to such globals from the thin LTO module.
@@ -403,12 +407,12 @@ void splitAndWriteThinLTOBitcode(
auto &Ctx = MergedM->getContext();
SmallVector<MDNode *, 8> CfiFunctionMDs;
for (auto *V : CfiFunctions) {
- Function &F = *cast<Function>(V);
+ Function &F = *cast<Function>(V->getAliaseeObject());
SmallVector<MDNode *, 2> Types;
F.getMetadata(LLVMContext::MD_type, Types);
SmallVector<Metadata *, 4> Elts;
- Elts.push_back(MDString::get(Ctx, F.getName()));
+ Elts.push_back(MDString::get(Ctx, V->getName()));
CfiFunctionLinkage Linkage;
if (lowertypetests::isJumpTableCanonical(&F))
Linkage = CFL_Definition;
@@ -428,29 +432,24 @@ void splitAndWriteThinLTOBitcode(
NMD->addOperand(MD);
}
- SmallVector<MDNode *, 8> FunctionAliases;
+ MapVector<Function *, std::vector<GlobalAlias *>> FunctionAliases;
for (auto &A : M.aliases()) {
if (!isa<Function>(A.getAliasee()))
continue;
auto *F = cast<Function>(A.getAliasee());
-
- Metadata *Elts[] = {
- MDString::get(Ctx, A.getName()),
- MDString::get(Ctx, F->getName()),
- ConstantAsMetadata::get(
- ConstantInt::get(Type::getInt8Ty(Ctx), A.getVisibility())),
- ConstantAsMetadata::get(
- ConstantInt::get(Type::getInt8Ty(Ctx), A.isWeakForLinker())),
- };
-
- FunctionAliases.push_back(MDTuple::get(Ctx, Elts));
+ FunctionAliases[F].push_back(&A);
}
if (!FunctionAliases.empty()) {
NamedMDNode *NMD = MergedM->getOrInsertNamedMetadata("aliases");
- for (auto *MD : FunctionAliases)
- NMD->addOperand(MD);
+ for (auto &Alias : FunctionAliases) {
+ std::vector<Metadata *> Elts;
+ Elts.push_back(MDString::get(Ctx, Alias.first->getName()));
+ for (auto *A : Alias.second)
+ Elts.push_back(MDString::get(Ctx, A->getName()));
+ NMD->addOperand(MDTuple::get(Ctx, Elts));
+ }
}
SmallVector<MDNode *, 8> Symvers;
diff --git a/llvm/test/Transforms/LowerTypeTests/Inputs/exported-funcs.yaml b/llvm/test/Transforms/LowerTypeTests/Inputs/exported-funcs.yaml
index 5457e36573bb7..81df2f198f91b 100644
--- a/llvm/test/Transforms/LowerTypeTests/Inputs/exported-funcs.yaml
+++ b/llvm/test/Transforms/LowerTypeTests/Inputs/exported-funcs.yaml
@@ -19,4 +19,12 @@ GlobalValueMap:
15859245615183425489: # guid("internal")
- Linkage: 7 # internal
Live: true
+ 1062103744896965210: # guid("alias1")
+ - Linkage: 4 # weak
+ Live: true
+ Aliasee: 16594175687743574550 # guid("external_addrtaken")
+ 2510616090736846890: # guid("alias2")
+ - Linkage: 0 # weak
+ Live: true
+ Aliasee: 16594175687743574550 # guid("external_addrtaken")
...
diff --git a/llvm/test/Transforms/LowerTypeTests/export-alias.ll b/llvm/test/Transforms/LowerTypeTests/export-alias.ll
index 45b4db63def18..25d34833c82c3 100644
--- a/llvm/test/Transforms/LowerTypeTests/export-alias.ll
+++ b/llvm/test/Transforms/LowerTypeTests/export-alias.ll
@@ -1,21 +1,19 @@
; RUN: opt -S %s -passes=lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/exported-funcs.yaml | FileCheck %s
;
-; CHECK: @alias1 = weak alias [8 x i8], ptr @external_addrtaken
-; CHECK: @alias2 = hidden alias [8 x i8], ptr @external_addrtaken
+; CHECK: @alias1 = alias [8 x i8], ptr @external_addrtaken
+; CHECK: @alias2 = alias [8 x i8], ptr @external_addrtaken
; CHECK-NOT: @alias3 = alias
; CHECK-NOT: @not_present
target triple = "x86_64-unknown-linux"
-!cfi.functions = !{!0, !2, !3}
-!aliases = !{!4, !5, !6}
+!cfi.functions = !{!0, !2, !3, !4}
+!aliases = !{!5, !6}
!0 = !{!"external_addrtaken", i8 0, !1}
!1 = !{i64 0, !"typeid1"}
-!2 = !{!"alias1", i8 1, !1}
-; alias2 not included here, this could happen if the only reference to alias2
-; is in a module compiled without cfi-icall
-!3 = !{!"alias3", i8 1, !1}
-!4 = !{!"alias1", !"external_addrtaken", i8 0, i8 1}
-!5 = !{!"alias2", !"external_addrtaken", i8 1, i8 0}
-!6 = !{!"alias3", !"not_present", i8 0, i8 0}
+!2 = !{!"alias1", i8 0, !1}
+!3 = !{!"alias2", i8 0, !1}
+!4 = !{!"alias3", i8 0, !1}
+!5 = !{!"external_addrtaken", !"alias1", !"alias2"}
+!6 = !{!"not_present", !"alias3"}
diff --git a/llvm/test/Transforms/ThinLTOBitcodeWriter/function-alias.ll b/llvm/test/Transforms/ThinLTOBitcodeWriter/function-alias.ll
index efc04e99f0459..74693c1312b01 100644
--- a/llvm/test/Transforms/ThinLTOBitcodeWriter/function-alias.ll
+++ b/llvm/test/Transforms/ThinLTOBitcodeWriter/function-alias.ll
@@ -7,11 +7,16 @@ define hidden void @Func() !type !0 {
ret void
}
-; CHECK1: !aliases = !{![[A1:[0-9]+]], ![[A2:[0-9]+]], ![[A3:[0-9]+]]}
+; CHECK1: !cfi.functions = !{![[F1:[0-9]+]], ![[F2:[0-9]+]], ![[F3:[0-9]+]], ![[F4:[0-9]+]]}
+; CHECK1: !aliases = !{![[A:[0-9]+]]}
-; CHECK1: ![[A1]] = !{!"Alias", !"Func", i8 1, i8 0}
-; CHECK1: ![[A2]] = !{!"Hidden_Alias", !"Func", i8 1, i8 0}
-; CHECK1: ![[A3]] = !{!"Weak_Alias", !"Func", i8 0, i8 1}
+; CHECK1: ![[F1]] = !{!"Func", i8 0, ![[T:[0-9]+]]}
+; CHECK1: ![[T]] = !{i64 0, !"_ZTSFvvE"}
+; CHECK1: ![[F2]] = !{!"Alias", i8 0, ![[T]]}
+; CHECK1: ![[F3]] = !{!"Hidden_Alias", i8 0, ![[T]]}
+; CHECK1: ![[F4]] = !{!"Weak_Alias", i8 0, ![[T]]}
+;
+; CHECK1: ![[A]] = !{!"Func", !"Alias", !"Hidden_Alias", !"Weak_Alias"}
@Alias = hidden alias void (), ptr @Func
@Hidden_Alias = hidden alias void (), ptr @Func
@Weak_Alias = weak alias void (), ptr @Func
|
Created using spr 1.3.6-beta.1
Created using spr 1.3.6-beta.1
vitalybuka
approved these changes
Jul 30, 2025
There was a problem hiding this comment.
Now ResI pointer looks like don't belong here,
I'd move out ArrayRef change into a separate patch and combine with removal of ResI
#151272
llvm-sync bot
pushed a commit
to arm/arm-toolchain
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Jul 30, 2025
With the current aliases metadata we lose information about which groups of aliases survive symbol resolution. This causes various problems such as #150075 where symbol resolution breaks the link between alias groups. In this redesign of the aliases metadata, we stop representing the individual aliases in !aliases. Instead, the individual aliases are represented in !cfi.functions in the same way as functions, and the alias groups (i.e. groups of symbols with the same address) are stored in !aliases. At symbol resolution time, we filter out all non-prevailing members of !aliases; the resulting set is used by LowerTypeTests to recreate the aliases. With this change it is now possible for a jump table entry to refer to an alias in one of the ThinLTO object files (e.g. if a function is non-prevailing but its alias is prevailing), so instead of deleting them, rename them with the ".cfi" suffix. Fixes #150070. Fixes #150075. Reviewers: teresajohnson, vitalybuka Reviewed By: vitalybuka Pull Request: llvm/llvm-project#150690
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With the current aliases metadata we lose information about which groups
of aliases survive symbol resolution. This causes various problems such
as #150075 where symbol resolution breaks the link between alias groups.
In this redesign of the aliases metadata, we stop representing the
individual aliases in !aliases. Instead, the individual aliases are
represented in !cfi.functions in the same way as functions, and the
alias groups (i.e. groups of symbols with the same address) are stored
in !aliases. At symbol resolution time, we filter out all non-prevailing
members of !aliases; the resulting set is used by LowerTypeTests to
recreate the aliases.
With this change it is now possible for a jump table entry to refer
to an alias in one of the ThinLTO object files (e.g. if a function is
non-prevailing but its alias is prevailing), so instead of deleting them,
rename them with the ".cfi" suffix.
Fixes #150070.
Fixes #150075.