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[memprof] Refactor readMemProf (NFC) #149663

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Jul 20, 2025
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[memprof] Refactor readMemProf (NFC) #149663

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130 changes: 70 additions & 60 deletions llvm/lib/Transforms/Instrumentation/MemProfUse.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -361,6 +361,74 @@ static void addVPMetadata(Module &M, Instruction &I,
}
}

static void
handleAllocSite(Instruction &I, CallBase *CI,
ArrayRef<uint64_t> InlinedCallStack, LLVMContext &Ctx,
OptimizationRemarkEmitter &ORE, uint64_t MaxColdSize,
const std::set<const AllocationInfo *> &AllocInfoSet,
std::map<std::pair<uint64_t, unsigned>, AllocMatchInfo>
&FullStackIdToAllocMatchInfo) {
// We may match this instruction's location list to multiple MIB
// contexts. Add them to a Trie specialized for trimming the contexts to
// the minimal needed to disambiguate contexts with unique behavior.
CallStackTrie AllocTrie(&ORE, MaxColdSize);
uint64_t TotalSize = 0;
uint64_t TotalColdSize = 0;
for (auto *AllocInfo : AllocInfoSet) {
// Check the full inlined call stack against this one.
// If we found and thus matched all frames on the call, include
// this MIB.
if (stackFrameIncludesInlinedCallStack(AllocInfo->CallStack,
InlinedCallStack)) {
NumOfMemProfMatchedAllocContexts++;
uint64_t FullStackId = 0;
if (ClPrintMemProfMatchInfo || recordContextSizeInfoForAnalysis())
FullStackId = computeFullStackId(AllocInfo->CallStack);
auto AllocType = addCallStack(AllocTrie, AllocInfo, FullStackId);
TotalSize += AllocInfo->Info.getTotalSize();
if (AllocType == AllocationType::Cold)
TotalColdSize += AllocInfo->Info.getTotalSize();
// Record information about the allocation if match info printing
// was requested.
if (ClPrintMemProfMatchInfo) {
assert(FullStackId != 0);
FullStackIdToAllocMatchInfo[std::make_pair(FullStackId,
InlinedCallStack.size())] = {
AllocInfo->Info.getTotalSize(), AllocType};
}
}
}
// If the threshold for the percent of cold bytes is less than 100%,
// and not all bytes are cold, see if we should still hint this
// allocation as cold without context sensitivity.
if (TotalColdSize < TotalSize && MinMatchedColdBytePercent < 100 &&
TotalColdSize * 100 >= MinMatchedColdBytePercent * TotalSize) {
AllocTrie.addSingleAllocTypeAttribute(CI, AllocationType::Cold, "dominant");
return;
}

// We might not have matched any to the full inlined call stack.
// But if we did, create and attach metadata, or a function attribute if
// all contexts have identical profiled behavior.
if (!AllocTrie.empty()) {
NumOfMemProfMatchedAllocs++;
// MemprofMDAttached will be false if a function attribute was
// attached.
bool MemprofMDAttached = AllocTrie.buildAndAttachMIBMetadata(CI);
assert(MemprofMDAttached == I.hasMetadata(LLVMContext::MD_memprof));
if (MemprofMDAttached) {
// Add callsite metadata for the instruction's location list so that
// it simpler later on to identify which part of the MIB contexts
// are from this particular instruction (including during inlining,
// when the callsite metadata will be updated appropriately).
// FIXME: can this be changed to strip out the matching stack
// context ids from the MIB contexts and not add any callsite
// metadata here to save space?
addCallsiteMetadata(I, InlinedCallStack, Ctx);
}
}
}

static void readMemprof(Module &M, Function &F,
IndexedInstrProfReader *MemProfReader,
const TargetLibraryInfo &TLI,
Expand Down Expand Up @@ -554,66 +622,8 @@ static void readMemprof(Module &M, Function &F,
if (AllocInfoIter != LocHashToAllocInfo.end() &&
// Only consider allocations which support hinting.
isAllocationWithHotColdVariant(CI->getCalledFunction(), TLI)) {
// We may match this instruction's location list to multiple MIB
// contexts. Add them to a Trie specialized for trimming the contexts to
// the minimal needed to disambiguate contexts with unique behavior.
CallStackTrie AllocTrie(&ORE, MaxColdSize);
uint64_t TotalSize = 0;
uint64_t TotalColdSize = 0;
for (auto *AllocInfo : AllocInfoIter->second) {
// Check the full inlined call stack against this one.
// If we found and thus matched all frames on the call, include
// this MIB.
if (stackFrameIncludesInlinedCallStack(AllocInfo->CallStack,
InlinedCallStack)) {
NumOfMemProfMatchedAllocContexts++;
uint64_t FullStackId = 0;
if (ClPrintMemProfMatchInfo || recordContextSizeInfoForAnalysis())
FullStackId = computeFullStackId(AllocInfo->CallStack);
auto AllocType = addCallStack(AllocTrie, AllocInfo, FullStackId);
TotalSize += AllocInfo->Info.getTotalSize();
if (AllocType == AllocationType::Cold)
TotalColdSize += AllocInfo->Info.getTotalSize();
// Record information about the allocation if match info printing
// was requested.
if (ClPrintMemProfMatchInfo) {
assert(FullStackId != 0);
FullStackIdToAllocMatchInfo[std::make_pair(
FullStackId, InlinedCallStack.size())] = {
AllocInfo->Info.getTotalSize(), AllocType};
}
}
}
// If the threshold for the percent of cold bytes is less than 100%,
// and not all bytes are cold, see if we should still hint this
// allocation as cold without context sensitivity.
if (TotalColdSize < TotalSize && MinMatchedColdBytePercent < 100 &&
TotalColdSize * 100 >= MinMatchedColdBytePercent * TotalSize) {
AllocTrie.addSingleAllocTypeAttribute(CI, AllocationType::Cold,
"dominant");
continue;
}

// We might not have matched any to the full inlined call stack.
// But if we did, create and attach metadata, or a function attribute if
// all contexts have identical profiled behavior.
if (!AllocTrie.empty()) {
NumOfMemProfMatchedAllocs++;
// MemprofMDAttached will be false if a function attribute was
// attached.
bool MemprofMDAttached = AllocTrie.buildAndAttachMIBMetadata(CI);
assert(MemprofMDAttached == I.hasMetadata(LLVMContext::MD_memprof));
if (MemprofMDAttached) {
// Add callsite metadata for the instruction's location list so that
// it simpler later on to identify which part of the MIB contexts
// are from this particular instruction (including during inlining,
// when the callsite metadata will be updated appropriately).
// FIXME: can this be changed to strip out the matching stack
// context ids from the MIB contexts and not add any callsite
// metadata here to save space?
addCallsiteMetadata(I, InlinedCallStack, Ctx);
}
}
handleAllocSite(I, CI, InlinedCallStack, Ctx, ORE, MaxColdSize,
AllocInfoIter->second, FullStackIdToAllocMatchInfo);
continue;
}

Expand Down
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