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[nfc][pgo] const-ify some APIs in InstrProfSymtab (#153284)

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The main reason some `const` - sounding APIs weren't const was because their state is lazily updated (ensuring ordering).
This commit is contained in:
Mircea Trofin 2025-08-13 18:08:08 +02:00 committed by GitHub
parent 0045bfca9c
commit 7efceca079
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3 changed files with 31 additions and 25 deletions
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50
llvm/include/llvm/ProfileData/InstrProf.h
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@ -526,24 +526,27 @@ private:
// so it doesn't use a StringSet for function names.
StringSet<> VTableNames;
// A map from MD5 keys to function name strings.
std::vector<std::pair<uint64_t, StringRef>> MD5NameMap;
mutable std::vector<std::pair<uint64_t, StringRef>> MD5NameMap;
// A map from MD5 keys to function define. We only populate this map
// when build the Symtab from a Module.
std::vector<std::pair<uint64_t, Function *>> MD5FuncMap;
mutable std::vector<std::pair<uint64_t, Function *>> MD5FuncMap;
// A map from MD5 to the global variable. This map is only populated when
// building the symtab from a module. Use separate container instances for
// `MD5FuncMap` and `MD5VTableMap`.
// TODO: Unify the container type and the lambda function 'mapName' inside
// add{Func,VTable}WithName.
DenseMap<uint64_t, GlobalVariable *> MD5VTableMap;
mutable DenseMap<uint64_t, GlobalVariable *> MD5VTableMap;
// A map from function runtime address to function name MD5 hash.
// This map is only populated and used by raw instr profile reader.
AddrHashMap AddrToMD5Map;
mutable AddrHashMap AddrToMD5Map;
AddrIntervalMap::Allocator VTableAddrMapAllocator;
// This map is only populated and used by raw instr profile reader.
AddrIntervalMap VTableAddrMap;
bool Sorted = false;
// "dirty" flag for the rest of the mutable state. lookup APIs (like
// getFunction) need the mutable state to be sorted.
mutable bool Sorted = false;
static StringRef getExternalSymbol() { return "** External Symbol **"; }
@ -565,8 +568,10 @@ private:
// If the symtab is created by a series of calls to \c addFuncName, \c
// finalizeSymtab needs to be called before looking up function names.
// This is required because the underlying map is a vector (for space
// efficiency) which needs to be sorted.
inline void finalizeSymtab();
// efficiency) which needs to be sorted. The API is `const` because it's part
// of the implementation detail of `const` APIs that need to first ensure this
// property of ordering on the other mutable state.
inline void finalizeSymtab() const;
public:
InstrProfSymtab() : VTableAddrMap(VTableAddrMapAllocator) {}
@ -676,24 +681,25 @@ public:
}
/// Return a function's hash, or 0, if the function isn't in this SymTab.
LLVM_ABI uint64_t getFunctionHashFromAddress(uint64_t Address);
LLVM_ABI uint64_t getFunctionHashFromAddress(uint64_t Address) const;
/// Return a vtable's hash, or 0 if the vtable doesn't exist in this SymTab.
LLVM_ABI uint64_t getVTableHashFromAddress(uint64_t Address);
LLVM_ABI uint64_t getVTableHashFromAddress(uint64_t Address) const;
/// Return function's PGO name from the function name's symbol
/// address in the object file. If an error occurs, return
/// an empty string.
LLVM_ABI StringRef getFuncName(uint64_t FuncNameAddress, size_t NameSize);
LLVM_ABI StringRef getFuncName(uint64_t FuncNameAddress,
size_t NameSize) const;
/// Return name of functions or global variables from the name's md5 hash
/// value. If not found, return an empty string.
inline StringRef getFuncOrVarName(uint64_t ValMD5Hash);
inline StringRef getFuncOrVarName(uint64_t ValMD5Hash) const;
/// Just like getFuncOrVarName, except that it will return literal string
/// 'External Symbol' if the function or global variable is external to
/// this symbol table.
inline StringRef getFuncOrVarNameIfDefined(uint64_t ValMD5Hash);
inline StringRef getFuncOrVarNameIfDefined(uint64_t ValMD5Hash) const;
/// True if Symbol is the value used to represent external symbols.
static bool isExternalSymbol(const StringRef &Symbol) {
@ -701,11 +707,11 @@ public:
}
/// Return function from the name's md5 hash. Return nullptr if not found.
inline Function *getFunction(uint64_t FuncMD5Hash);
inline Function *getFunction(uint64_t FuncMD5Hash) const;
/// Return the global variable corresponding to md5 hash. Return nullptr if
/// not found.
inline GlobalVariable *getGlobalVariable(uint64_t MD5Hash);
inline GlobalVariable *getGlobalVariable(uint64_t MD5Hash) const;
/// Return the name section data.
inline StringRef getNameData() const { return Data; }
@ -748,7 +754,7 @@ Error InstrProfSymtab::create(const FuncNameIterRange &FuncIterRange,
return Error::success();
}
void InstrProfSymtab::finalizeSymtab() {
void InstrProfSymtab::finalizeSymtab() const {
if (Sorted)
return;
llvm::sort(MD5NameMap, less_first());
@ -758,14 +764,14 @@ void InstrProfSymtab::finalizeSymtab() {
Sorted = true;
}
StringRef InstrProfSymtab::getFuncOrVarNameIfDefined(uint64_t MD5Hash) {
StringRef ret = getFuncOrVarName(MD5Hash);
if (ret.empty())
StringRef InstrProfSymtab::getFuncOrVarNameIfDefined(uint64_t MD5Hash) const {
StringRef Ret = getFuncOrVarName(MD5Hash);
if (Ret.empty())
return InstrProfSymtab::getExternalSymbol();
return ret;
return Ret;
}
StringRef InstrProfSymtab::getFuncOrVarName(uint64_t MD5Hash) {
StringRef InstrProfSymtab::getFuncOrVarName(uint64_t MD5Hash) const {
finalizeSymtab();
auto Result = llvm::lower_bound(MD5NameMap, MD5Hash,
[](const std::pair<uint64_t, StringRef> &LHS,
@ -775,7 +781,7 @@ StringRef InstrProfSymtab::getFuncOrVarName(uint64_t MD5Hash) {
return StringRef();
}
Function* InstrProfSymtab::getFunction(uint64_t FuncMD5Hash) {
Function *InstrProfSymtab::getFunction(uint64_t FuncMD5Hash) const {
finalizeSymtab();
auto Result = llvm::lower_bound(MD5FuncMap, FuncMD5Hash,
[](const std::pair<uint64_t, Function *> &LHS,
@ -785,7 +791,7 @@ Function* InstrProfSymtab::getFunction(uint64_t FuncMD5Hash) {
return nullptr;
}
GlobalVariable *InstrProfSymtab::getGlobalVariable(uint64_t MD5Hash) {
GlobalVariable *InstrProfSymtab::getGlobalVariable(uint64_t MD5Hash) const {
return MD5VTableMap.lookup(MD5Hash);
}

2
llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp
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@ -519,7 +519,7 @@ Error InstrProfSymtab::create(SectionRef &Section) {
return Error::success();
}
StringRef InstrProfSymtab::getFuncName(uint64_t Pointer, size_t Size) {
StringRef InstrProfSymtab::getFuncName(uint64_t Pointer, size_t Size) const {
if (Pointer < Address)
return StringRef();
auto Offset = Pointer - Address;

4
llvm/lib/ProfileData/InstrProf.cpp
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@ -684,13 +684,13 @@ Error InstrProfSymtab::addFuncWithName(Function &F, StringRef PGOFuncName,
return Error::success();
}
uint64_t InstrProfSymtab::getVTableHashFromAddress(uint64_t Address) {
uint64_t InstrProfSymtab::getVTableHashFromAddress(uint64_t Address) const {
// Given a runtime address, look up the hash value in the interval map, and
// fallback to value 0 if a hash value is not found.
return VTableAddrMap.lookup(Address, 0);
}
uint64_t InstrProfSymtab::getFunctionHashFromAddress(uint64_t Address) {
uint64_t InstrProfSymtab::getFunctionHashFromAddress(uint64_t Address) const {
finalizeSymtab();
auto It = partition_point(AddrToMD5Map, [=](std::pair<uint64_t, uint64_t> A) {
return A.first < Address;