================
@@ -1070,8 +1084,138 @@ void InstrProfiling::maybeSetComdat(GlobalVariable *GV,
Function *Fn,
GV->setLinkage(GlobalValue::InternalLinkage);
}
-GlobalVariable *InstrProfiling::setupProfileSection(InstrProfInstBase *Inc,
- InstrProfSectKind IPSK) {
+static inline bool shouldRecordVTableAddr(GlobalVariable *GV) {
+ if (!profDataReferencedByCode(*GV->getParent()))
+ return false;
+
+ if (!GV->hasLinkOnceLinkage() && !GV->hasLocalLinkage() &&
+ !GV->hasAvailableExternallyLinkage())
+ return true;
+
+ // This avoids the profile data from referencing internal symbols in
+ // COMDAT.
+ if (GV->hasLocalLinkage() && GV->hasComdat())
+ return false;
+
+ return true;
+}
+
+// FIXME: Does symbollic relocation from 'getFuncAddrForProfData' matter here?
+static inline Constant *getVTableAddrForProfData(GlobalVariable *GV) {
+ auto *Int8PtrTy = Type::getInt8PtrTy(GV->getContext());
+
+ // Store a nullptr in __profvt_ if a real address shouldn't be used.
+ if (!shouldRecordVTableAddr(GV))
+ return ConstantPointerNull::get(Int8PtrTy);
+
+ return ConstantExpr::getBitCast(GV, Int8PtrTy);
+}
+
+/// Get the name of a profiling variable for a particular variable.
+static std::string getVarName(GlobalVariable *GV, StringRef Prefix) {
+ StringRef Name = getPGOName(*GV);
+ return (Prefix + Name).str();
+}
+
+void InstrProfiling::getOrCreateVTableProfData(GlobalVariable *GV) {
+ assert(!DebugInfoCorrelate &&
+ "Value profiling is not supported with lightweight instrumentation");
+ if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
+ return;
+
+ if (GV->getName().starts_with("llvm.") ||
+ GV->getName().starts_with("__llvm") ||
+ GV->getName().starts_with("__prof"))
+ return;
+
+ // VTableProfData already created
+ auto It = VTableDataMap.find(GV);
+ if (It != VTableDataMap.end() && It->second)
+ return;
+
+ GlobalValue::LinkageTypes Linkage = GV->getLinkage();
+ GlobalValue::VisibilityTypes Visibility = GV->getVisibility();
+
+ // This is to keep consistent with per-function profile data
+ // for correctness.
+ if (TT.isOSBinFormatXCOFF()) {
+ Linkage = GlobalValue::InternalLinkage;
+ Visibility = GlobalValue::DefaultVisibility;
+ }
+
+ LLVMContext &Ctx = M->getContext();
+ Type *DataTypes[] = {
+#define INSTR_PROF_VTABLE_DATA(Type, LLVMType, Name, Init) LLVMType,
+#include "llvm/ProfileData/InstrProfData.inc"
+ };
+
+ auto *DataTy = StructType::get(Ctx, ArrayRef(DataTypes));
+
+ // Used by INSTR_PROF_VTABLE_DATA MACRO
+ Constant *VTableAddr = getVTableAddrForProfData(GV);
+ StringRef VTableName = GV->getName();
+ StringRef PGOVTableName = getPGOName(*GV);
+ // Record the length of the vtable. This is needed since vtable pointers
+ // loaded from C++ objects might be from the middle of a vtable definition.
+ uint32_t VTableSizeVal =
+ M->getDataLayout().getTypeAllocSize(GV->getValueType());
+
+ Constant *DataVals[] = {
+#define INSTR_PROF_VTABLE_DATA(Type, LLVMType, Name, Init) Init,
+#include "llvm/ProfileData/InstrProfData.inc"
+ };
+
+ auto *Data =
+ new GlobalVariable(*M, DataTy, false /* constant */, Linkage,
+ ConstantStruct::get(DataTy, DataVals),
+ getVarName(GV, getInstrProfVTableVarPrefix()));
+
+ Data->setVisibility(Visibility);
+ Data->setSection(getInstrProfSectionName(IPSK_vtab, TT.getObjectFormat()));
+ Data->setAlignment(Align(8));
+
+ const bool NeedComdat = needsComdatForCounter(*GV, *M);
+
+ // GV is the data structure to record vtable information.
+ // Place the global variable for per-vtable profile data in a comdat group
+ // if the associated vtable definition is a COMDAT. This makes sure only one
+ // copy of the variable for the vtable will be emitted after linking.
+ auto MaybeSetComdat = [&](GlobalVariable *GV, StringRef GroupName) {
+ bool UseComdat = (NeedComdat || TT.isOSBinFormatELF());
+ if (UseComdat) {
+ // Create a new comdat group using the name of the global variable as
+ // opposed to using the comdat group of the vtable.
+ Comdat *C = M->getOrInsertComdat(GroupName);
+ // For ELF, when not using COMDAT, put the vtable profile data into a
+ // nodeduplicate COMDAT which is lowered to a zero-flag zero group.
+ // This allows -z -start-top-gc to discard the entire group when the
----------------
snehasish wrote:
s/start-top-gc/start-stop-gc
https://github.com/llvm/llvm-project/pull/66825
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